Kalimar Light Meter - Photo courtesy of B's Camera Collection Pages!
Analog Hand-held Light Meters for Photographers
by Robert Monaghan
Analog Hand-held Light Meters for Photographers
by Robert Monaghan
Related Local Links:
Weston Light Meters - History, Sources, Repairs
EV Exposure Value System
Film Reciprocity Failure
Related Links:
Review of Zone VI Pentax Digital Spot and Sekonic L-508 Light Meters
(Paul Butzi)
Minolta
(Europe)
Gossen (Germany)
Sekonic
Sekonic L-508 and modified Zone VI Pentax Digital Spot (Paul Butzi)
B&H
PhotoVideo Light Meter Pages
Weston Euromaster II
meter
Weston Master Site
Weston Euromaster Meter (source in U.K.)
Ultimate Exposure
Computer
Why
Your Light Meter Lies to You (18% grey..)
Review of Zone VI modified Pentax Digital Spot and Sekonic L-508 Meters
Light Reading Techniques
for Hand Held Meters by Heinz Richter
Exposure Guide
(Paper) (Black Cat Mfg)
Exposure Meters and
Spectra Meters etc.
Weston Meters
Gallery
Exposure Settings From
Charts [2/2001]
Simon Spaans' Meter
Collection (1100+) [updated 8/2002]
Grey Cards
Incident vs. Reflective Meters
Weston & Sekonic
Meter Manuals (courtesy of Richard Urmonas) [5/2002]
Bob Shell's NECCC Metering Talk Notes
[8/2002]
Steve Hoffman's
Metering and Exposure Pages [8/2002]
Zone System and Lightmeters (Ken Rockwell) [9/2002]
Norwood Director Story (+new cells..) (John Desq) [9/2003]
Many photographers like the Weston Master series (III and up through the
latest Euro-masters) of selenium light meters as a battery independent,
accurate meter for daylight metering. These Weston meters are also easily
adapted to the Zone system for direct readout of exposure based on the
Zone system. Such meters often sell on EBAY auctions for $20 US and
up.
Other photographic authors and users recommend the Gossen Luna Pro (or in
Europe, the Lunasix series) and the various successors of either cadmium
sulfide or silicon sensor meters. While these meters use batteries, they
are much more accurate in low light levels, including the claim of being
able to meter exposures even in moonlight (hence, Luna Pro as a name).
These meters also feature a number of accessories for use with view
camera ground glass backs, microscopes, spotmeter attachments, and other
accessories that turn them into a light metering system.
The older Gossen Luna Pro series analog light meters used mercury
batteries which are not readily available in the USA due to new
anti-mercury pollution laws (but we supply sources online in links below).
The later Gossen professional light meters use more standardized batteries
(9 volt, silver cell batteries, etc.) that are still readily available.
Not everyone knows about these battery related issues, so older Luna Pro
meters often sell for prices (e.g., circa $100 US) that are close to
prices for much later digital as well as analog light meters with current
battery setups. Many photographers swear by their Luna Pro and related
light meters and make a place for them in their carry-around camera
bags.
What about the hundreds of other older analog light meters out there? We
will look at the types of light meters below, effects of different sensor
types, the battery problem issues, and specific models and features such
as incident light metering options in the remainder of this article. You
can get some very good buys in used analog meters and receive a useful
tool for your photography for surprisingly little money.
While they are a great value for the professional photographer,
especially in the studio, we won't focus more on them here. Instead, I
recommend that you refer to current photo dealers pages for more
information. B&H PhotoVideo has an excellent light
meter page listing dozens of mostly digital meters from Gossen,
Minolta, Pentax, Quantum, Polaris, Soligor, Sekonic, Sheperd, and Wein.
My major focus here is on those older analog light meters such as the
Gossen Luna Pro and Weston Master series that remain popular with serious
amateur photographers.
A handheld light meter is much less intrusive than sticking your 35mm SLR
camera in someone's face to get a light meter reading. Handheld light
meters can also be modified for zone system use (see below). Many
handheld meters make it easy to estimate under-exposure and over-exposure
limits for different types of film too.
The biggest benefit of most hand-held analog light meters is the ability to
offer an incident light meter reading mode. Personally, I find incident
light metering superior to the reflected light metering used in most 35mm
SLR and medium format camera metering systems.
Unfortunately, there are lots of situations where the world isn't grey,
but mostly white or mostly black. Moreover, sometimes you really want to
properly expose a subject that isn't like or isn't lighted like the rest
of the scene. To some extent, you can bracket and use the +/- 2 EV
exposure offset or ASA/ISO dial offset techniques to vary the actual
exposure (e.g., for backlighting and
other tricky lighting situations).
Today's more expensive electronic cameras now offer a whole series of
metering options, ranging from an overall averaging option to segmented
matrix metering to a spotmeter option (see below). Some manufacturers use
in-camera computers and databases to meter the scene by many matrix light
sensors and pick their best guess for what the scene should be exposed so
as to produce the best results. While results in tricky lighting
situations are improved, the best results are likely to come from a
photographer using the light meter and past experience to set the
exposure to meet one's photographic goals. A handheld light meter can be
one tool in making this process easier and more accurate.
Why is incident light metering a useful feature? Suppose you want to
properly meter a black cat sitting in a coal bin? Or the same black cat
sitting on a child's lap, with the child wearing a bright white dress or
jacket. Your reflected light meter will try to turn the black on black
situation into an average 18% grey image, which will be quite wrong. For
the cat in the lap, you are likely to either over-expose (if you meter
the black cat) or under-expose (if you meter the white dress).
But with an incident light meter reading, you don't have to worry about
either situation. The incident light meter reading will be based on the
amount of light incident on the scene, and produce an exposure that will
keep the black on black scene or the black on white scene reasonably
exposed. At best, you can hedge your bets by bracketing a stop or so,
depending on your film.
Most selenium cell meters have a dual range setup to handle the full
range of daylight situations from bright daylight to their dimmest
settings. This dual range system may use a baffle or blocking material to
reduce the amount of light reaching the selenium sensor. Other setups
used a different resistor selected by a high/low switch to make their
meter respond to both bright and dim lighting situations.
The poor dim light sensitivity of the older selenium meters is not much
of a problem if you use relatively slow films in typical daylight
situations. But films have become much faster in the last 40 or so years,
and many cameras can take photos in light that is much too dim to be
metered accurately by most selenium cell light meters. Still, these
selenium light
meters work fine for most daylight and indoor scenes, and provide a
battery independent light meter option.
One place where such battery independence can be of real value is in cold weather shooting. Battery powered meters in
cameras and handheld meters (e.g., CdS or SBC battery powered light
meters) can be adversely impacted by cold weather and give erroneous
readings.
Another benefit of selenium meters is their light sensitivity curve,
which more closely matches that of film than some other sensors. Selenium
meters are also relatively fast responding to major shifts in light levels,
compared to their cadmium sulfide (CdS) meter cousins. Finally, they are
often quite inexpensive on the used market since they are often older models.
Over time, some selenium meters have eroded the moisture proofing
originally provided to the selenium cell, absorbed moisture, and become
less accurate. Selenium is a poisonous element, and while it is not
especially dangerous encased in the meter, there are some minor concerns
that you can absorb some selenium from touching the cells directly - so
don't touch them directly. Actually, it is more likely that the acids on
your fingers would etch and harm the selenium cell than the reverse. But
in any case, don't touch is a good recommendation.
So far as I know, there are still a few selenium based light meters being
made in Western countries such as Germany, with a variant of the Weston
Euro-master VI being a major example. However, it is very difficult to
get a replacement selenium cell element for a broken meter for most brands.
Quality Light Metric - 6922 Hollywood Blvd, Suite 210, Hollywood, Calif.
90028 (323)467-2265 - is the only service I know that specializes in
light meter repairs (especially the Weston meters).
All cadmium sulfide (CdS) meters require a battery for operation. In the
past, this battery has been a mercury battery to take advantage of the
inherent constant voltage output curve of those batteries. Today, this
fact represents a possible problem for users and buyers of older CdS
meters. In the USA, new laws have made it harder to get mercury batteries
such as the once popular PX625 series often used to power light meters
and camera gear. You can still get such batteries from non-USA sources in Canada
and overseas.
One of the key problems to be aware of in using cadmium sulfide based
light meters is delays in reaching a final correct setting. This problem
is especially noticeable as you go from very bright lighting to a dimly
lighted room or subject. In these cases, it can take many seconds for the
meter to drop to its final correct reading (as in ten or twenty seconds
plus). Going from dim to bright light is not a problem. But you need to
remember this trick, and allow time for the meter needle to reach its
final value. If you don't, then you may greatly underexpose the dimly
lighted scene due to this meter reading error.
Like the selenium meter, the SBC light sensor generates a tiny amount of
electricity when its PN junction is hit by light. The principle is
similar to the silicon
cells used in solar powered calculators and similar devices. But since
the cell is tiny in size, the amount of electricity generated is equally
tiny,
and too little to power the meter. So like CdS meters, most SBC meters
require a separate battery for powering the meter's electronics and readouts.
Silicon based sensors have a huge advantage over the previous cadmium
sulfide based meters. If you expose a CdS meter to a bright light source,
it may take several tens of seconds or minutes for the cell to return to
its maximum sensitivity to dim light. Silicon based sensors don't have
this CdS "memory" problem, and respond rapidly and accurately to changes
in light intensity. So if you do elect to buy and use a CdS meter, keep
in mind this potential problem when going from bright to darker metering
situations. By buying a SBC silicon sensor meter, you can have instant
response and not worry about having to wait for accurate meter readings.]
In fact, most silicon based sensors are so fast responding that they can
easily be used to measure the light from short duration electronic strobe
flashes down to a few ten-thousandths of a second! In lower cost SBC
light meters, the electronics don't offer this feature due to the cost.
But the higher end modern digital light meters often offer both ambient
and flash meter readings.
The more modern digital flash meters do lots more tricks, but cost more
too. One trick is the ability to accumulate light from many flash
exposures. Where a lot of light is needed, and the available flash power
is insufficient, studio photographers will darken their studios and make
multiple exposures to "paint" light onto the subject as desired. The
accumulating feature of some digital flash metering models makes this
simple to meter accurately.
Color temperature meters usually work by having several light sensors,
covered by carefully chosen filters (e.g., red and blue). The output of
these sensors goes to electronics (such as a bridge circuit) where they
are used to vary a readout (e.g., an analog meter pointer). The scale of
the meter is calibrated in color temperature units (typically degrees
Kelvin) up to about 10,000 degrees (the color temperature of open shade
with clear skylight lighting).
So what? Given the color temperature, and the type of film in use, you
can precisely determine which color filter will provide the best results.
For example, an overcast sky (7,000 degree Kelvin) requires a #85B filter
when using tungsten lighting films balanced for 3,200 degrees Kelvin. But
for daylight balanced color films (5,500 degrees Kelvin), you need to use
a 81C warming filter.
For more on color temperature conversion and filters to use, see our Filters FAQ and associated tables. In
general, few amateur photographers use color temperature meters, but many
studio photographers swear by (and at) them when trying to balance
different light sources on location shots.
Spotmeters are very handy for situations where you can't walk up to a
distant subject to take an incident light meter reading or a reflected
meter reading. A moose is standing in a clearing in front of a dark,
barely lighted forest background. You can't just walk up to the moose to
take a meter reading. So you take a spot meter reading of the moose, and
expose for the moose, letting the forest background go to dark shadows.
If you metered with a regular area meter in most cameras, you would get
an over-exposure that would turn the moose into a white ghost in front
of an average grey (18%) forest.
Most hand-held spotmeters are one degree meters, meaning they measure a
circle corresponding to roughly one degree in width (out of 360 degrees
in a circle). Some analog and digital meters have an accessory spot meter
attachment that converts their area averaging meters to read a smaller
field such as 10 or 15 degrees. So be sure to check which kind of spot
meter coverage you are buying, and that you need.
For obvious reasons, a spotmeter can be very handy for studying a scene
and breaking it up into zones. But there are a few analog meters which
are also very popular with zone system users. The Weston Master series
(esp. III through V) are inexpensive meters which are readily used with
zone systems. Many zone users adapt them with a taped on scale that
converts the analog meter reading directly into corresponding zones.
Earlier light meters sometimes employed archaic scales tied to particular
film types or manufacturer product lines, such as the H&D and Schneiner
speed scales. Edward Faraday Weston's invention
of the Weston Exposure Meter (patented October 1935) was the first of many
sealed selenium cell meters from the Weston Corporation. These early
Weston series of selenium meters used the Weston scale, which had the
advantage of being independent of both film type (curve) and manufacturer.
The Weston scale was evidently very popular with photographers, and was
adopted (with an offset) as the American standard for rating film speeds.
Fortunately for users, the Weston scale is simply offset one step from the
ASA/ISO scale familiar to photographers in the USA. So Weston 50
corresponds to ASA 64, Weston 64 corresponds to ASA 80, and so on.
You may also find older meters rated in footcandles, which can be
converted to exposure index (effectively, ASA/ISO ratings) using a
formula in posting on EV page. Light measured in
LUX is also
related to footcandles (as is "candelas"), but are
more commonly encountered today in video cameras where such low light
level units help differentiate low light performance. These units
tend to be linear (double the light, double the units), while some
popular photographic film rating scales (e.g., DIN) tend to compress
the scale (e.g., logarithmic related rather than linear scales).
If you have some European light meters, film, or cameras, they may use
the DIN (Deutsches Industries) number instead of ASA/ISO ratings. For
many cameras and films made in the Soviet Empire and post-Soviet
countries, other film scales such as GOST are popular. Here is
a table from a posting that relates these systems.
|
|
While reciprocity failure impacts both the ultra-fast exposure and longer
exposure ends of the time scale, we usually encounter it in exposures
longer than one second. Moonlight and night-time
exposures require special guides to provide additional exposure times
needed to adjust for this lower film sensitivity to longer light
exposures.
Our Moonlight and night-time exposure page
has some guides for starting exposures for various film speeds and
typical photographic situations. I find these recommended ratings
surprisingly accurate and useful, whether I am shooting downtown store
windows by night or at a night-time circus show. Fireworks and longer
night-time landscape exposures by moonlight are also described on these
pages. I mention these local resources since it is often impossible to
meter some scenes, especially at night and with high contrast situations.
So these guides provide good starting points - and bracket from there!
Besides the useful information on meter type (reflected and incident
light), you can see which meters required an accessory incident light
attachment (which might not be included in the kit you buy?). Moreover,
about half the meters didn't offer an incident light capability, which is
a strike against them in my book. Finally, the price of the meter in 1953
dollars is some indication of the quality of construction and features.
Most of these meters sell for less than they did new, albeit in 1999
dollarettes. To restate these 1953 prices in today's dollars, multiply
by about 7 using our Consumer Price Index
table.
| Name of Meter | Manufacturer | Reflected Light | Incident Light | price | Notes |
| Actino C | Weigand, Germany | Yes | $24.50 | ||
| Bertram Amateur | Bertram, Germany | Yes | $14.95 | ||
| Bertram Chrolon | Bertram, Germany | Yes | $24.50 | ||
| Bertram Chrostar | Bertram, Germany | Yes | $24.95 | ||
| Dejur Dual Professional | Dejur-Amsco Corp | Yes | Yes | $26.95 | |
| Dejur 5B | Dejur-Amsco Corp | Yes | $15.95 | price includes case | |
| G.E. DW-68 | General Electric Co. Cleveland | Yes | Yes | $24.50 | (6 multiplier masks for bright light $1.50) |
| GE PR-1 | General Electric Co. Cleveland | Yes | Yes | $32.50 | incident light attachment included |
| G.E. PR-30 Mascot | General Electric Co. Cleveland | Yes | Yes | $15.95 | |
| Ideal | Federal Instrument Corp. | Yes | $9.95 | price includes case | |
| Ikophot 1A | Carl Zeiss Opton, Germany | Yes | Yes | $28.00 | incident light attachment included |
| Leica Meter | Metrawatt, Germany (E. Leitz) | Yes | Yes | $24.00 | price includes case |
| Minirex II | Rex, Germany (Saul Bower Inc) | Yes | $9.95 | ||
| Minox | Minox, ermany | Yes | $21.45 | ||
| Norwood Director | Director Products Corp NY | Yes | Yes | $32.95 | photogrid reflected light attachment included |
| Patrol Delux | Warren Mechanisms NY | Yes | $16.50 | wristwatch style | |
| Patrol Aristocrat | Warren Mechanisms NY | Yes | $24.00 | wristwatch style | |
| Polaroid - G.E. | Polaroid Corp, Cambridge MA | Yes | $14.25 | ||
| Prize (formerly Prix) | Dorner, Germany | Yes | Yes | $12.95 | incident light attachment and case included |
| Pullin | Pullin, Great Britain | Yes | $14.95 | ||
| Sixtomat | Gossen, Germany (Kling P.C.) | Yes | $25.00 | ||
| Sixtomat I | Gossen, Germany (Kling P.C.) | Yes | Yes | $28.50 | |
| Skan SM-3 Quick | G-M Labs Inc., Chicago IL | Yes | $17.50 | ||
| Skan SM-4 Viewfinder | G-M Labs Inc., Chicago IL | Yes | Yes | $24.50 | incident light attachment included |
| Swiss Lux II | Hilba, Switzerland (Karl Heitz Inc) | Yes | Yes | $19.95 | price includes case |
| Tower Meter | Sears Roebuck Co., Chicago IL | Yes | $10.95 | ||
| Weston Cadet | Weston Elec. Instru. Corp. Newark | Yes | Yes | $19.95 | |
| Weston Master II | Weston Elec. Instru. Corp. Newark | Yes | Yes | $29.95 | invercone incident light attachment ($2.50) |
| Weston Master II Cine | Weston Elec. Instru. Corp. Newark | Yes | Yes | $29.95 | " " - special model for cine (movie) use |
| Source: Modern Photography August 1953, p.77-109, On the Button by Charles Hellman, p.108 Exposure Meters Table | |||||
| Name | price | type | speeds | f/stops | notes |
| Bewi Boy | 21.95 | selenium | 4-1/1000 | 1.4-22 | ASA 25-400 |
| Bewi Quick | 32.95 | selenium | 2 min-1/1000 | 1.4-22 | asa 12-3200 |
| Bewi Super L | 64.95 | CdS | 1 hr-1/1000 | 1-45 | asa 12-3200, incident light converter |
| Bower CM-1 | 14.95 | CdS | 30-1/2000 | 1-32 | asa 6-3200 |
| Bower CP-3 | 20.95 | selenium | 1-1/1000 | 1-32 | asa 12-3200 |
| Bower 85 | 17.95 | selenium | 60-1/2000 | 1-32 | asa 6-12,000 |
| Gossen C-mate | 49.95 | CdS | 15min-1/200 | 1.4-22 | asa 6-3200, incident light converter |
| gossen Luna Pro | 124.95 | CdS | 8hrs - 1/400 | 1-90 | asa 6-25000, incident light converter |
| gossen pilot-2 | 39.95 | selenium | 4 min-1/1000 | 1.4-22 | asa 6-3200, incident light converter |
| gossen scout-2 | 29.95 | selenium | 60-1/1000 | 1.4-22 | asa 6-3200, incident light converter |
| gossen super pilot | 74.95 | CdS | 2 hrs-1/1000 | 1-45 | asa 6-12500, incident light converter |
| Hanimax PR 125 | 18.95 | selenium | 1-1/1000 | 1-32 | asa 6-12,000 |
| Hanimax PR-135 | 24.95 | CdS | 2min-1/8000 | 1.4-45 | asa 6-12,000, pushbutton |
| hanimax PR-140 | 21.95 | CdS | 8-1/1000 | 1-32 | asa 6-12,000 |
| kalimar A-1 | 15 | selenium | 60-1/1000 | 1-32 | asa 3-3200, incident attachment (not built-in) |
| kalimar CdS-31 | 30 | CdS | 8min-1/8000 | 1-32 | asa 6-12000, incident light converter |
| Kalimar K433 Zone | 32 | CdS | 8min-1/8000 | 0.7-45 | asa 1.5-12,500, incident light converter |
| lentar pr-66 | 22 | CdS | 8min-1/1000 | 1-32 | asa 6-12,000, pushbutton |
| sekonic autolumi L86 | 17 | selenium | 8min-1/2000 | 1-32 | asa 6-12,000 |
| sekonic apex L-218 | 75 | CdS | 30min-1/400 | 1-64 | asa 6-12,000; incident light converter |
| sekonic marine II L16 | 130 | CdS | 1/1/2000 | 1-64 | asa 6-12,000 underwater meter |
| sekonic microlite L96 | 45 | CdS | 16-1/2000 | 1-32 | asa 6-12,000 |
| soligor auto meter | 14.5 | selenium | 30-1/2000 | 1-32 | asa 3-3200 |
| soligor selector | 22.5 | CdS | 30-1/2000 | 1-32 | asa 6-6400 |
| soligor UF | 21 | CdS | 30-1/2000 | 1-32 | asa 6-6400 |
| vivitar 24 | 21.95 | CdS | 2hrs-1/8000 | 1-64 | asa 6-6400 |
| vivitar 30 | 15.95 | selenium | 15min-1/800 | 1-64 | asa 6-25,000 |
| vivitar 43 | 29.95 | CdS | 8hrs-1/8000 | 1-64 | asa 6-25,000, incident light converter |
Notes: the more expensive meters tend to have built-in incident light
attachments, for measuring ambient light directly (e.g., small diffusion
cone). The CdS meters require a battery, but have larger ranges in low light.
Price can be a useful index to quality both within and between brands.
The PR-1 has a dual sensitivity scale to cover the full range from bright
daylight to dimmer indoor lighting. You set a series of dials to your film
ASA rating and rotate the main dial until an indicator needle matches the
light meter pointer. A very handy feature is a push-button that freezes
the meter reading when you release the button. This feature makes it easy
to take a reading by pressing and releasing the button, then adjusting the
dial to get an exact reading. There are brackets on the indicator needle
and the dials to show under-exposure and over-exposure brackets. While you
can also do various plate film and cine (movie) film exposure
calculations, few users will need most of these scales.
Today, I use this meter as a low cost backup
battery-independent light meter for daylight use. It provides both
incident and reflected light meter readings, thanks to the attachment. I
can use it in cold weather photography too.
Finally, using this meter and my older medium format and 35mm SLR cameras
gives me a deja-vu or nostalgic "blast from the past" photographic
experience. I can better appreciate and emulate the techniques of past
masters such as Edward Weston while using similar equipment and techniques.
From: [email protected] (Richard Knoppow)
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Testing Accuracy of Light Meters
Date: Sat, 29 May 1999
"Chris Newman" [email protected] wrote:
>How does one test the accuracy of a hand held light meter. I know how to >check for correct film exposure but that takes into account any >peculiarities in lens aperture and shutter speed. Is there any way to know >how accurate just the meter is. > >Chris Newman
About the only practical way is to compare it to a known good meter.
Selenium cell meters should be checked at both ends of the scale since
they tend to become non-linear with age and will often read right for
low ligh but low for stronger light. A reflected light meter can be
checked against an incident meter by using an 18% gray card although
there are some errors that can creep in. A good deal of care is
required in comparing meters with different shapes of light diffusers
or reflected light meters with different acceptance angles.
I am able to get agreement among several meters of various ages,
among them a Luna-Pro (my standard), a Sekonik L-28c, a General
Electric PR-1, the TTL meter in my Nikon F-1 and the meter on a
Rolleiflex 2.8E. I have a couple of other old Selenium meters which
have the common non-linearity reading low for bright sunlight (by a
stop or more) but right in low level light.
---
Richard Knoppow
Los Angeles, Ca.
[email protected]
From Rollei Mailing List:
Date: Wed, 18 Aug 1999
From: Pablo Kolodny [email protected]
Subject: Re: [Rollei] 1st roll on a Rollei
"Kotsinadelis, Peter (Peter)" wrote:
> Mark, > > Buy a good meter, preferably new. I was taken by someone wwhen I purchased > used some time back. My favorite meter is the Sekonic L-508. Very good. I > also have the L-328F which is a backup for me. I don't use it as much as > the 508 though which is my preference.
Peter, I think that a Gossen Lunassix 3 would work great and make save
money in comparison with the "fashion" L-508. I do use a Lunasix 3 with
"tele" accesory attached after using Minoltas Flashmeter IV, Autometer
IIIF, Autometer IVF and so...even used and still own a Gossen Ultra Spot
but Luna "feels" better than others. Btw, I saw there�s a new one Lunasix
3/Pro made in black, somedy I�ll go for it...too.
Pablo K
rec.photo.equipment.large-format
From: David M [email protected]
[1] Re: Gossen Repairs
Date: Fri Oct 22 09:39:02 CDT 1999
Bogen Photo Corp
565 E Cresent Ave
Ramsey, NJ 07446-0506
attn: Service/Repair
From Rollei List:
Date: Wed, 08 Sep 1999
From: Richard Lahrson [email protected]
Subject: Re: [Rollei] OT: Weston Meters Invercone
cbabing3 wrote:
> I suspect they're still being made, if this link is still current. I've > been tempted to order one just because the first meter I ever used was my > father's Weston (don't remember which number) from the '40s. > http://www.megatron.co.uk/euromaster2/index.html
Greetings!
The Weston Master II and III are, for me, more useful, because the
needle's scale is marked in candles-per-square-foot. Later model's dropped
this, starting with the V model, I think (may need correction here).
If your film speed is 125, simply take the square root as the f/stop,
in this case f/11 and the reciprocal of the candles-per-square-foot reading
is the shutter speed: e.g. 200 candles-per-square-foot is 1/200 of a second.
Lots of big words for a simple idea! It is very quick, and avoids using
the meter's dial.
Have a happy,
Rich Lahrson
[email protected]
From Rollei Mailing List:
Date: Wed, 08 Sep 1999
From: "G. Lehrer" [email protected]
Subject: Re: [Rollei] OT: Weston Meters Invercone
...
Kip
The current price in dollars would be the price in Sterling times the
exchange rate plus shipping and duty, which would bring it to over $300.
The best bet is to buy a used Weston Master II, III, or V and send it to
Quality Light Metric for service.
The Euromaster is just about identical to the Weston Master V which was
made in England. Not that there is anything wrong with things made in
Scotland. My wife was.
Jerry
From Rollei Mailing List:
Date: Wed, 08 Sep 1999
From: Richard Knoppow [email protected]
Subject: Re: [Rollei] OT: Weston Meters
At 10:12 AM 9/8/99 +0200, you wrote:
>> from Jerrt :
>> So far my Weston Master III and V have had NO battery
>> problems. (Selenium photo-voltaic cells)
>
>An off-topic question about Weston Meters : I have one but lost the
>"invercone" incident light diffusor ; does anybody on this list has an
>idea about where I could get another one ? thanks,
>--
>Emmanuel BIGLER
>[email protected]
I see Invercones occasionally at local camera shows. There are at two
versions for different meters and they are not interchangable.
----
Richard Knoppow
Los Angeles,Ca.
[email protected]
From Rollei Mailing List:
Date: Thu, 9 Sep 1999
From: [email protected]
Subject: Re: [Rollei] OT: Weston Meters Invercone
WESTON METERS, INVERCONE
Thanks everybody on his list to provide me information a bout Weston
Meters and Invercone. This is a summary of the answers (received more
than 10), useful to people searching this list's archives in the
future :
-1- Weston Meters, a famous selenium cell for photographic use, is to
date (1999/9/9 : no bug until now on my computer)
manufactured in England by :
Megatron Limited
165 Marlborough Road, London N19 4NE, (England)
Tel: 0171 272 3739 (int +44 171 272 3739)
Fax: 0171 272 5975 (int +44 171 272 5975)
http://www.megatron.co.uk/euromaster2/index.html
-2- for spare parts or repair in the US you may try :
Quality Light Metric,
6922 Hollywood Blvd # 210, Los Angeles, CA 90028 (USA)
(323) 467-2265
Attn: George Milton
-3- It is possible to find spare invercones from used equipment
dealers ; but since the equipment is available as new, it might be
possible also to buy a new one from the manufacturer.
-4- For people like me who lost the invercone, you may also ;-)
purchase a used (or even a new) Weston complete, keep invercone #2
for metering with meter #1, and keep the spare meter #2 in your
fridge (with your stock film). In case next time, for example, you
would forget your meter#1 on the top of Mount Whitney, keep the
invercone in your pocket, and realize it when drinking a nice cold
beer back to Lone Pine, CA (just to remember nice places where my
Rolleiflex has been, but I had no Weston Meter at the time).
------------
I'm really amazed by the efficiency of this list and would be glad to
help the people next time in return of this valuable service.
--
Emmanuel BIGLER [email protected]
From Rollei Mailing List:
Date: Fri, 10 Sep 1999
From: Richard Knoppow [email protected]
Subject: Re: [Rollei] OT: Weston Meters Invercone
>This is great I am psyched! Anyone use this it looks great. How important is the >invercone you need it for incident readings? Tips on calibrating my Weston >Master II?
The invercone is needed only for incident readings. Its a pretty good
light integrator with about the right directional properties.
The Weston meter was intended for reflected light readings. Along about
1947 Don Norwood introduced his Director meter based on many years of work
developing an incident light meter. It became very popular, especially in
the motion picture industry. The Norwood Director popularized incident
readings and the other manufacturers had to catch up. Weston's answer was
the Invercone. It is essentially an inverted sphere with similar
integration characteristis. That is, the reading is dependent on angle, as
it is with a sphere. This is not true for some other adaptors, particularly
the ones supplied by General Electric for their meters.
The Norwood meter is still around as the Sekonic Studio Master, IMHO a
very good meter and needs no battery. It has a grid fitting which allows it
to make reflected light readings but its not as good at that as the Weston.
The Spectra Combi meter is also based on the Norwood design. His original
meter was essentially the Spectra meter, the smaller Director coming out
perhaps a year later.
A meter can be calibrated by comparing it to a known good one by reading
a flat even surface.
Selenium cells age. At some point they become non-linear. As a result
they may read correctly for low light levels but not for high levels. The
meter must be checked at both ends of the meter scale using a single
attenuator setting. Damaged selenium cells will be found to read low for
high intensities, the error being on the order of a stop. This can not be
corrected by setting adjusting the film speed setting since the error is
not constant but varies with light level. The only cure is to replace the
cell.
Weston cells seem to be tougher than others. Part of Weston's patent was
a method of manufacturing and sealing the cell which protected it from
moisture. Moisture and heat are the enemies of selenium cells. I have a
Weston Master II which seems to be just fine. The Weston speed settings can
be used for ISO speeds, just use the next lower number on the scale. My
meter tends toward under exposure, probably reflecting a correction factor
included in the original Weston film ratings.
BTW, Weston introduced probably the first _independant_ speed rating
system. Prior to the Weston system several sytems were used, each of which
could be cheated in some way. Ratings were supplied by manufacturers and
tended to exagerate speed. The Weston numbers were determined by Weston for
use with the meter and were quite reliable.
Some care in making reflected light readings must be employed with the
Weston meter since it has a very wide angle of acceptance and may give
false readings on distant views where it will see a lot of sky. With some
practice it is a very reliable meter.
If you are interested primarily in incident readings I suggest you also
look at the Sekonic meter. Its a better meter for incident light work. I
don't know what the price of the current Weston is but unless it is much
cheaper I think the nod must go to the Sekonic here. For mostly reflected
light work the Weston is superior.
----
Richard Knoppow
Los Angeles,Ca.
[email protected]
From Rollei Mailing List:
Date: Sun, 24 Oct 1999
From: "G. Lehrer" [email protected]
Subject: [Rollei] Zone System and the Rollei
RUGers
Knowing of my interest in Ansel Adams Zone System, a number of you have
inquirerd of me as to a source of information more complete and
applicable than Adams works which are scattered thru at least FOUR
books.
My suggestion has been, and is now, find a copy of Minor White's book "The
New Zone System Manual", which pulls it all together. It is the only book
which shows how to bring all the variations of the photographic process
under control.
I will admit that this book is hard to find. I have loaned my only copy to
a few people and have only gotten raves. (Guys, I didn't write it!) I am
trying to find another copy or two. No, I don't know what they are worth.
Minor White uses a Weston Ranger 9 meter in his illustrations, so you
don't really need a 2degree spotmeter to work along
I'll let you know if I can find some more of these books. I'd appreciate
if you did the same.
Jerry
From Rollei Mailing List:
Date: Sun, 24 Oct 1999
From: Curtis & Linda Croulet [email protected]
Subject: Re: [Rollei] Zone System and the Rollei
I don't have the "*New* Zone System Manual," but I have White's
"Zone System Manual New Revised Edition" (Morgan & Morgan,
1968). White's Zone System scale is is shorter than Adams'. For
White, minimum possible density is Zone I ("The blackest black
that a print can be made to yield"), not Zone 0 as in Adams ("Total
black in print"), and White's maximum is Zone IX ("...pure white of
the paper base"), whereas for Adams Zone IX still has tonality.
From Rollei Mailing List:
Date: Wed, 6 Oct 1999
From: Paul Benjamin Newland [email protected]
Subject: [Rollei] OT: Gossen Light Meter Calibration
Greetings...
I'm in the processes of trying to calibrate a Gossen CdS Super
Pilot meter and I need some advice.
I purchased this meter on ebay to use with my Rolleicord. The
seller told me it was in great condition. When I got it I
found that the battery was dead and corroded. I cleaned it
up, put in a new mercury battery, and then found that the meter
read about 2 stops low on the high range and about one stop low on
the low range. I contacted the seller, telling him of my problems,
and asked how did he determined that the meter was in "great
condition"? In the end, we agreed that we'd call it even if he
rebated me all but $12 on the purchase price of the meter. At
that point I had a working but inaccurate meter for $12.
I then called Gossen to see about getting it calibrated and they
told me that they no longer worked on this meter and it was not
repairable or recalibratable.
Being the tinkering sort, I took the cover off the meter to peek
around a bit. The mechanics are very interesting but I found
that the electronics seem to be surprisingly simple. I didn't
fully disassemble the meter but it looks like it's just a simple
series circuit with a single point calibration. I could be wrong
about this since I didn't look on the bottom side of the PC board,
but in checking all the circuit nodes with a ohm meter (low voltage,
low current, suitable for checking sensative meter movements
without harm) , it looks like the circuit is as follows.
batt
test
switch
---------|-----CdS-------
| | nc |
| | |
| --><---Reostat----|
+ no R3 |
BATT |
1.35V Reostat
- Coarse R1
| |
| |
| Reostat
| Fine R2
| |
| |
-------------------------
My guess is that the calibration routine is as follows....
1. Set R2 to mid scale.
2. Place meter in known flux density of light
(maybe EV12 at 100 ASA would be a good value).
3. Adjust R1 to get meter to indicate as close as possible to
EV12.
4. Adjust R2 to get meter to be dead-on EV12.
5. Press batt test button and adjust R3 to indicate
middle of "batt OK" range.
6. Compare this newly adjusted meter to known good meter in light
values from EV 5 to EV 20. If it is within 1/3 stop then it's
OK to use.
End
Does this seem reasonable. Anything I'm overlooking here?
Any and all advice is welcome.
Paul
From Rollei Mailing List:
Date: Tue, 21 Sep 1999
From: "Thomas A. Frank" [email protected]
Subject: Re: [Rollei] Exposure meters
>RUGers > >To get back to non-personal subjects, Have any of you ever heard of ,or >know of a Weston Master VI (that's 6) Meter? I always thought that the >Master V, which phased into the Euromaster, was the last Master. Please >help me out on this.
Weston Master 6 (arabic, not roman, numeral), aka the Model 560.
I have one sitting right here on the table.
What would you like to know about it?
FWIW, I bought it from Quality Light Metric, although that was a LONG
time ago.
Tom Frank
Thomas A. Frank (KA2CDK)
rec.photo.equipment.35mm
From: [email protected] (HRphoto)
[1] Re: Light Meter Basics
Date: Sat Oct 30 13:22:40 CDT 1999
>Any recommendations on any books, sources, etc. on the basics of light >metering, i.e. E numbers, incident and reflected light, etc? Looking to get >a >good understanding of light meter operation, before buying one
Go to; http://www.f32.com
and see under articles "Light Reading Techniques with Hand Held
Lightmeters."
Heinz
HRphotography
http://hometown.aol.com/hrphoto/myhomepage/business.html
From Rollei Mailing List:
Date: Thu, 02 Mar 2000
From: Marc James Small [email protected]
Subject: Re: [Rollei] Meters - innie or outie?
Craig Roberts wrote:
>Internal meters, no matter how exalted the brand, seem to have a much >shorter and more troubled life than their host camera bodies. When buying >an older camera, whether it be a Leica, Rollei or whatever, I'd rather >obtain one without a trouble-prone meter.
This is a myth. A grand and glorious myth, but a myth for the all of it.
First, there are no Leica RF's older than 16 years with internal meters,
and parts for these will be available for aeons. Second, for the
selenium-metered Rollei TLR's, repairs are simple and inexpensive and
generally consist of cleaning the electrical contacts. Third, selenium
meters most closely match the response pattern of chemical films and,
despite their weakness, are thus preferable to later metering chemistries.
I have Pre-War Contax III's whose meters match my most modern meters
accurately and, on occasion, outperform them.
I do agree that, if you use your camera as a hammer for errant nails, a
selenium meter, with its rather delicate mechanical linkages, is not for
you. But, for those of us who attempt, however errantly, to keep from
using our cameras as basketballs, a selenium inbuilt meter can be most
wonderful.
Marc
[email protected]
From Rollei Mailing List:
Date: Mon, 6 Mar 2000
From: [email protected]
Subject: Re: selenium cells Re: [Rollei] OFF TOPIC selenium cells
> are selenium cells for meters still being manufactured? by whom?
Gossen fabricates the Bix, a cheap (~US$50) model
Sekonic has a selenium cell also.
And the Weston is still manufactured in the UK as dicussed last year
on his list.
> the issue of selenium (a poisonous metal) and limited number of new > cameras using such cells (vs SBC silicon cells etc) would suggest a > dwindling stock?
I guess this is not the issue. Otherwise, as previoulsly mentioned all
fluorescent tubes which contain mercury would be discontinued. And
also to fabricate Silicon devices you need arsine gas wich is so
poisonous that you'd better never think of a possible accident in the
Silicon Valley.
Simply selenium cells need to be big to be as "sensitive" as an
amplified silicon cell. So impossible wih selenium cells to even
imagine an equivalent of a modern multi-zone TTL meterering system.
And also to the best of my knowledge there has never been such a thing
like a selenium flash-meter probably due to the *slow* response time
of the cell (?? to be checked with specialists of the technical
history of photography)
> the general posts I have seen suggest the main problem is corrosion > of contacts, moisture attacking the cells, and aging of glue used to > mount them (to a yellow color) which effects the cell performance.
A severe drawback in the old times when cameras could live (and still
live : the RUG list is there to prove it every day) for 50 years or
more ; but what about the liquid crystal display of most modern 35mm
SLR's which will die within ~5 to 10 years ;-);-). Try to use such a
camera wihout the LCD panel...
--
Emmanuel BIGLER
[email protected]
Date: Fri, 31 Dec 1999
From: [email protected] (William Wright)
Newsgroups: rec.photo.misc
Subject: Re: How (un)accurate are lightmeters?
This discussion prompted me to read the ANSI spec for meters. I don't
know how any (if any) manufacturers promise to meet the ANSI spec, but
at least it provides a point of reference.
ANSI re-wrote their spec in 1974. Prior to 1974, the spec stated
clearly that the allowable tolerance was plus or minus 1/3 step when the
needle is in the "central area" of the dial, and the allowable tolerance
was plus or minus 1/2 step when the needle is outside the central area.
With digital meters that don't have a needle or dial, I suppose the
meter was considered to always be in the 'central area' of the 'dial.'
So prior to 1974, two meters would fail ANSI's spec if they measured
more than 2/3 step apart in the central portion of the dial, or 1 step
apart if the illumination forced the needle to either edge of the dial.
I'm relieved to see this because the concept of two meters being _2_
steps apart and still be called "within tolerance" seems inappropriate
to me.
The new spec (1974) doesn't declare a specific tolerance. It merely
defines how the tolerance is to be measured. Perhaps this indicates
that modern manufacturing methods are too varied for ANSI to agree on
what is 'acceptable' these days.
I don't know..... if anyone here has good solid knowledge about this,
I'd be interested to hear more about it.
Date: Fri, 31 Dec 1999
From: "Nicholas O. Lindan" [email protected]
Newsgroups: rec.photo.misc,rec.photo.technique.misc
Subject: Re: How (un)accurate are lightmeters?
[email protected] wrote:
> Accuracy and repeatability of lightmeters?
Is pretty bloody awful. Agreed.
Because of the great range of light they must be able to measure (17-20
stops or 130,000 - 1,000,000 : 1) lightmeters incorporate logarithmic
elements, usually simple diode or diode/transistor circuits, that
are not terribly accurate. Older units take the log in the meter
mechanics. They can usually hit the right answer by a factor of 2,
or about a stop.
Better meters, especially modern digital meters, do much better.
The best use V/F converters with variable integration times and
take the log in software. However, dark current error can be
significant if the light source is not chopped in sync. with the
measurement. I know of no photographic light meter that does this.
Stanford Research will be glad to sell you a lock-in amp, chopper,
detector and converter for 10 grand or so.
A decent light meter can be made for not a whole lot of money.
It is just that nobody has bothered.
--
Nicholas O. Lindan, Cleveland, Ohio [email protected]
From Rollei Mailing List:
Date: Mon, 3 Jan 2000
From: Bob Parsons [email protected]
Subject: Re: [Rollei] Filter exposure compensation
Rich Lahrson asked:
> I've just bought the Pentax Digital Spotmeter. I was under the > impression that something was altered to the meter which made it Zone > VI modified. Is this true? Or is the modification the addition of > a set of filters with some instructions and a 'zone dial' added to > the meter's calculator? Could you tell us which filters were offered > with the Zone VI modified meter? > > I'd appreciate hearing about this. Zone VI was Fred Picker's > equipment company. I had one of their print washers at one time. > I think Calumet handles the Zone VI products today.
Rich,
According to Calumet's web site www.calumetphoto.com the Zone VI meter has
the following modifications: step down baffles to reduce flare; broad
spectrum infrared coating to reduce reflections; infrared, ultraviolet and
visual range filters to match the meter's spectral response to film;
improved photo cell and calibration to within 1/6 stop linearity. All
these modifications are internal, there are no external filters to add.
In addition the meter has a stick on scale marked with zones making it
easy to place a reading on any zone. The scale is on the body behind the
EV ring. The modified meter looks identical to the regular one except for
the added zone scale and a sticker on the side saying it's been modified.
You can easily make your own zone scale, it has markings from Z1 to
Z8 spaced the same as the full stop values on the EV ring. The scale
is aligned with Z5 centered on the red mark on the TV/IRE scale.
In use, you measure the part of the subject you want to base the exposure
on, decide which on which zone to place it and set the measured EV
against that zone on the zone scale. You then read the speed aperture
combinations from the calculator. Once you have pegged a measured
EV to a zone in this way you can measure the EV of any part of the scene
and with reference to the zone scale instantly see which zone it lies on.
In Ansel Adams book The Negative (1997), the Zone System chapter
has a photo of a Pentax digital meter with a home made zone scale and
a full explanation of its use.
I wonder just how much difference the Zone VI modifications make in
practice, the unmodified meter has an excellent reputation. I believe the
now out of print book "Controls in Black and White Photograpy" by Dr. J
Richard Henry has a section comparing several spot meters including
the original and modified Pentax.
Bob Parsons. [email protected]
Date: Fri, 05 Nov 1999
From: [email protected] (Sheldon D. Stokes)
Newsgroups: rec.photo.equipment.35mm
Subject: Re: Old Weston Meter Readings vs ASA numbers?
[email protected] (ArlenPar) wrote:
> I have an old Weston Master II light meter and forgot the conversion factors to > get to today's ASA rating system. > > Does anyone the equivalent ASA numbers?
yes I do, this is out of the "photographic lab handbook"
ASA Weston 3 2.5 4 3 5 4 6 5 8 6 10 8 12 10 16 12 20 16 25 20 32 24 40 32 50 40 64 50 80 64 100 80 125 100 160 125 200 160 250 200 320 250 400 320 500 400 640 500 800 640 1000 800 1250 1000 1600 1250 2000 1600 2500 2000 3200 2500
Sheldon
From Rollei Mailing List:
Date: Wed, 22 Mar 2000
From: John Jensen [email protected]
Subject: RE: [Rollei] OT Screws
I don't know about the Master II but mine is the Master III. Many, many
years ago I sent it to Weston for servicing. I think I dropped it and the
meter pins came out of their bushings. After I received it from Weston I
noticed the oval sticker on the backside showed screwheads exposed (where
they were not exposed before). The position of the screws is under the
oval label sticker. very close to the edge (by the edge of the meter).
Check and see if there are screws there on yours. I just undid mine and
screws about 5/8 inch long came out and the back came off.
Let us know what you find.
John Jensen
....
Well, does anyone know what sort of
screwdriver/socket it is that Weston used on their Master II, holding the
whole assembly together? Or of some kind of homemade approach to get the
case apart without a saw or hammer?
Thanks, paul
From Rollei Mailing List:
Date: Wed, 22 Mar 2000
From: [email protected]
Subject: Re: [Rollei] OT Screws
John
My Weston Master II and III apparently have the clipped -head screws
holding the halves together. All my other Masters (IV, V, and Euromaster
require that the calculater dial be removed to take the case halves apart.
I really don't recommend that you do this casually. Send it to Quality
Light Metric.
Jerry
[Ed. note: we have many notes on light meter replacement batteries at:
Photo Battery Pages]
From Rollei Mailing List:
Date: Tue, 31 Aug 1999
From: Marc James Small [email protected]
Subject: Re: [Rollei] Batteries for Old Gossen Light Meters
At 08:31 AM 8/31/1999 -0700, Dave Wyman wrote:
>Does anyone know where and/or how I can get batteries that work for an >old Gossen Lunasix and a Luna Pro? I'd like to use them with a Rollei >that doesn't have a light meter.
These meters take the now-difficult-to-get mercury cells. BUT, if you
travel to your village camera emporium and pick up a Bogen 4145 kit for
under $20, your woes will be solved, as this adapts PX76 silver-oxide
cells to work the Gossen meters.
I have such a kit but haven't used it. But, then, I almost never use a
meter if the camera doesn't have an inbuilt one.
Marc
[Ed. Note: I agree about the Gossen Luna Pro F meter based on my own
experience, also price often under $100 and even $75 US used...]
From ROllei Mailing List:
Date: Fri, 29 Oct 1999
From: Godfrey DiGiorgi [email protected]
Subject: [Rollei] re: sekonic meter
The L508 is a magnificent meter but I find it bulky and awkward to carry.
I chose the Sekonic L328 model. It's much simpler, has a rotating incident
head which is very convenient, and has a 5 degree spot attachment that you
don't need to carry all the time if you don't want it. It's also a lot
smaller. I like it a lot and it's very accurate and easy to use.
The other meter I'd buy if I needed a second is a Gossen Luna Pro F, which
has the best analog readout I've ever used, and has various attachments
available for tremendous flexibility.
godfrey
Date: Fri, 29 Oct 1999
From: Logan McMinn [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Incident metering still needs correction?
In incident metering, you are not actually taking a meter reading of a
subject. The subject isn't a factor at all. What you are doing is
using the meter's dome in place of the subject to collect and integrate
the light which will fall on the subject when you make the exposure.
The dome is intentionally hemispherical -- a three dimensional
substitute for the actual subject. If the subject is strongly side lit,
then the dome should be held so that it, too, is strongly side lit. The
same is true for front lighting, back lighting, whatever.
Now that you have used the meter to determine the exposure setting, if
you "correct" it because your subject is light or dark, you are
defeating the whole concept of incident reading. Once you have
determined the correct exposure setting, then if you put a dark object
in front of the camera, it will be rendered as a dark area on the
resulting print or slide. If you put a light colored object in front of
the camera, it will be rendered as a light-colored object in the print.
You should only correct your exposure if that is not what you want, but
most of the time, it is exactly what you want.
Harry Kiesel wrote:
> If I take an incident light meter reading of a subject, do I still > have to correct for the fact that meters assume an average 18% gray?
From Rollei Mailing List:
Date: Sat, 30 Oct 1999
From: "Sheldon D. Stokes" [email protected]
Subject: Re: [Rollei] re: L508
>I'm not sure why everyone seems to think these meters won't be around in 10 >years? I have already had my L508 since the very day that it came out and >have used it frequently without any problems under some pretty tough >conditions... these babies were built to last...
True, I've got a weston IV that's well over 20 years old now. But that is
a very simple selenium cell and galvinometer movement. Not much to go
wrong over time.
The modern meters have a lot more electronics, and that could be a
problem. Elecrolytic capacitors tend to dry out or leak over time changing
their values. Carbon comp resistors also drift over time and temperature.
I also refurbish vacuum tube audio gear (my other hobby), and I've seen a
lot of old dried out caps in 20-50 year old gear.
Now with the sekonic meters, there's absolutely no reason for them to use
carbon comp resistors, they would most certainly be metal films, good for
longer than you are. The only risk is some power supply decoupling caps
that could go after a lot of years. But given that the meter uses a 1.5
volt supply, I'd bet there isn't even any electrolytic caps in there
either.
When I get my 408, you can be sure I'll take it apart, if anybody is
interested, I'll comment about the quality of the insides, and my
guestimates of longevity. I am hoping for the 408 as a christmas present
from my wife (I may buy it for her to give to me).
Sheldon
Date: Mon, 27 Mar 2000 11:27:01 -0500
From: Marc James Small
Roland Schregle wrote:
The older sequence is quite close to the modern one, and therefore
conversions aren't a problem.
The maximum difference is 1/5 stop. Most modern B&W films can accomodate
at least 3 stops overexposure and 2 underexposure, most modern
colour-print emulsions can accomodate 2 stops either way, and most modern
chromes can take at least 1/3 stop either way.
So, simply meter and shoot.
Marc
[email protected]
From Rollei Mailing List:
you wrote:
The magnet is part of the meter. A meter is a small electric motor. The
type in the Weston light meter is known as a D'Arsonval movement, one of
the most sensitive and accurate types. It has a coil of very fine wire
through which the current from the Selenium cell flows. The current in the
coil reacts with the magnet, rotating the coil around its pivot and moves
the pointer which is attached to the coil.
The stronger the magnetic field, the more sensitive the meter.
The meters in Selenium cell light meters must be very sensitive if the
meter is to be linear.
The magnets in these meters have a slightly eccentric pole pieces (the
part near the coil) in order to shape the scale.
Its very important in working on meter movements to avoid getting iron
filings into them. You would be surprized how plentiful little chips of
magnetic metal are. Its like getting dust on a negative. Once a bit of
metal gets into the meter movement it may be painfully difficult to get it
out again.
Weston was mainly in the electric meter business and made very high
quality ones.
----
Newsgroups: rec.photo.equipment.medium-format
Getting some "funky" low-range overexposure with your Luna-Pro?
If you have a Luna-Pro (older style) with the Gossen battery converter,
you need to change your silver batteries regularly. I had mine in
place for four years (since I had the meter rebuilt), and recently
discovered that on the low-range it was a stop off. Changing the batteries
brought it back on target.
Moral of the story - Luna-Pro is very sensitive to minute voltage changes,
so watch your battery age.
Note: The battery checker is not capable of detecting this - mine was well
into the red (OK) zone, and has been forever.
------------
Date: Wed, 22 Sep 1999
Access to the nuts holding both halves of the meter together is by
removing the setting dial on the face.(one large screw) Underneath are
two special nuts that usually require a small spanner wrench to remove.
Most dead Westons usually have a dead cell making repairs an exercise
in futility for the average person..
[Ed. note: the most often recommended light meter repair folks on the
WWW:]
Hi Guys -
Thanks for a great site. There is a new address for Quality Light
Metric in Hollywood, CA.
It is: 7060 Hollywood Blvd. Suite 415, Hollywood, CA 90028
Thanks again,
Paul White
From: [email protected]
[email protected] wrote:
I found a possibility:
http://www.johndesq.com/2000/exposure.htm
[update: use http://www.westonmaster.com ]
Hope this is of some help. You might try e-mailing the page master
directly, too.
From: [email protected]
[email protected] wrote:
Phil,
This is too wierd. I JUST got off the phone with Quality and will be
sending out my Euro-Master, Master V and Ranger 9 for repair/conversion
tomorrow. Ansel Adams in "Camera and Lens" says the Ranger 9 has an
angle of 18 degrees. FWIW the cell is NOT the part you look through.
They are adjacent to each other, about 2.5 inches apart. Presumably
they are corrected for parallax. I saw one recently for $75.00. Would
you be interested? If I can find it again I can send you the address.
I like the fact that the Westons can be used as incident meter as well
and the dial design is very useful. On the Master V you can read c/ft
square directly off the needle range 16 = 1600, 15 = 800, 14 = 400, 13
= 200 etc. Small, light and, except for the 9 fits right in a shirt
pocket.
The Euro Master is available new from John DesQ in the Netherlands (?)
More than you want to pay though I think.
Not that I'm aware of but you could do like I did and use a search
engine for "Weston Master V" etc. Google worked fine for me as did
Altavista. Personally I am not interested in anything older than a V.
It's not that the II and III are bad, they aren't. But you do have to
allow for the conversion of Weston Index #'s to ASA and they are by no
means spot meters.
Only thing I could think of would be the Gossen Luna Pro with the
variable angle attachment. I think that gets you down to 15 and 7
degrees angle of view? But you'd have to be lucky to get both of 'em
for $100.00. Norman McGrath used to use that meter until he upgraded.
I think it's more due to them being on the rare side, just not that
many made. However, they are swell.
From Rollei Mailing List:
you wrote:
The domes and accessories for the current meters fit all the previous
Sekonik meters but don't fit the original Director meter. The same for the
cells. Quality Light Metric told me they can replace the cells in original
Norwood meters by adapting the later ones but it is a painful job and they
will try to talk you out of it.
A word to the wise: Dont' keep the accessories in the pocket in the
meter case, they get lost too easily.
BTW, Don Norwood's original design became the Spectra meter, later the
Spectra
Combi. He shortly after designed the smaller version known as the
Director.
The current Sekonic Studio Deluxe is virtually identical and an
excellent meter. If you want a backup non-battery meter it would be my
choice over the current version of the Weston.
----
From hasselblad Mailing List:
[email protected] writes:
Any small light meters that can be
adapted to attach to the body of the
Hassie in some way, other than the meter
knob?
The Gossen Pilot 2 is a currently-made selenium-cell meter of tiny
proportions and there is a flash-shoe attachment available for it as an
option for under $10. It can be mounted in a prism accessory shoe, or the
shoe that slides onto the side rail of the 500-series. A small,
lightweight meter such as that, the Scout 3, or the Sekonic 158 (selenium)
or 188 (CdS) can also be attached to the lens hood of the 80 or longer
with self-stick velcro (I suggest a "cap keeper"-type lanyard be attached
also, just in case the meter gets knocked off its perch). I've done this
with a Gossen Luna-Pro Digital F, which is about the largest meter I'd
recommend for this application. Also, there is a meter made by Cosina
along with the "new" Voigtlaender rangefinders call the VC (you can view
it at www.cameraquest.com) which is a tiny modern LED affair made to go in
the flash shoe of an older Leica. They're about $200, though.
From ROllei Mailing List;
Both Marflex and Harry Fleenor have meters for the F models. They are
still
available factory new and cost about 150 bucks. Installation adds another
20-30 bucks, but if you have two hands and a good pair of eyes, you can do
the work yourself as it is not complicated. You just need to remember that
you must change both the meter body and the cell, as they are matched.
-_______________
From: "M. Reichmann" [email protected]
A review of the extremely versatile Sekonic L508 II meter and a tutorial
on how to use an incident light meter have now been posted to The Luminous
Landscape.
Both articles can now be found at
http://www.luminous-landscape.com/meters.htm
Michael Reichmann
www.luminous-landscape.com
The Web's most comprehensive site devoted to the art and technique of
landscape photography.
Sekonic L508 II Review and Incident Metering Tutorial
[Ed. note: Mr. Grabowski is a noted contributor to many rec.photo
groups!]
greg kerr [email protected] wrote:
My only comment is it won't be long before you don't use the grey
card, with the incident capabilities of the IIIF you will need the
card far less. An Autometer II F is what got me hooked on hand held
meters, I used this with a separate carrying case for some time. I've
had no experience with the IIIf but imagine it's similar to the II F I
used, which worked great. To this day, though I use Seconic meters
now I am hooked on hand held metering and rarely consider in camera
meter readings if I'm using a camera with a meter in it at all.
Incident metering rules in 90% of what I do , you may well find your
keeper rate to go up in regards to exposure from this worth while
investment you've made.
David Grabowski
From Leica Mailing List:
Jesse Hellman wrote:
The Gossen Luna-Pro Digital is probably the best handheld meter available
today.
Instant on. When it is off, you can take a reading as if it were on. It
turns on, takes a reading and displays the result. In a fraction of a
second. Other meters (Sekonic digital for instance - unless they've
changed recently) require a power-on cycle that tests the display and who
knows what else. Then after it is done (it takes its sweet time,) you can
then take a reading.
A "full" analog scale under the digital reading so you can instantly see
the digital reading in terms of where it lies on your f/stop ring. This
itself is worth the price of admission.
Hold the read button down and point the meter in various directions and
the analog scale will display the entire range you have scanned while
retaining the original reading the digital display and while the read
button is pushed, the "current" value is blinked on the analog scale.
Great for determining dynamic range and determining how to actually expose
for a complicated scene.
It will read a filter and set itself to automatically correct the exposure
reading for that filter for all subsequent readings. A couple of button
pushes will cancel out the stored filter correction.
And this is just the beginning of what it will do.
And it is small, thin, and the reflected reading is at only 25 degrees
which is more selective than most meters.
Go to http://www.bogenphoto.com/gossen_lunastar.htm to learn more.
I actually own a Gossen Luna Star F2, which has exactly the same
electronics and features, but is a different (larger) package and is meant
for mainly incident use. I like the intuitive and quick operation of the
F2 so much that I am going to buy a Luna-Pro for outdoor work.
Mark Rabiner has a Luna-Pro and can second everything I said.
Jim
From Rollei Mailing List;
you wrote:
Check the meter at both ends of the scale, that is for both dim and
bright light with the light attenuator in the same setting.
Selenium cells become non-linear with age or if moisture can leak
through the seals. The symptom is that they read OK for relatively dim
light but read low for bright light. If the error were constant at all
light levels it would be no problem, but it varies with the amount of
light striking the cell.
I don't know what the actual chemical change in the cell is that
produces this effect. Selenium cells are sensitive to excessive heat and
to moisture. The cells are sealed against moisture in manufacture but the
seal can break down with age. Some cells seem to last forever. I have an
old Weston Master II, made when Weston was still using Weston speeds,
which is perfectly accurate. I have some other Selenium meters of about
the same age or less, which are useless. It seems to be very individual.
The meter in my 2.8E seems to be pretty accurate, I've shot color with
it and the exposures were OK. It does not quite agree with my Luna Pro but
the differences are small.
Be careful comparing reflected light meters, the angle of view can
affect the readings and give the illusion of an error where there is none.
----
[Ed. note: Thanks to Simon for this handy tip! ...]
Hi Robert
You might like to add to the "Weston Light Meters - History, Current
Sources, Repairs" page that scans of the manual are available at
regards
From Rollei Mailing List:
You again Bob!
I would love to see that booklet. I kind of got into making light
meters for a while and had some fun with it. The cds cells are a decent
match in their response for our eyes, not perfect,a little biased toward
longer wavelengths with a little heel into the short ones too, but
pretty close. Turns out that the relationship between the resistance
change and light intensity is logarithmic. If you are within ten
percent on the resistance, you are probably within one tenth of a stop.
I have an acquaintance at a shop who lets me use one of the really nice
meters to calibrate with, and you can get them very very close.
Gene
From Rollei Mailing List:
Converting to CdS is not worth the bother.
The CdS cell has a response which is basically:
R = A . L ^(-B)
Where R is the resistance,
Now to linearise the CdS cell is not an easy task. A range of log /
antilog circuits exist. These are generally based on the current/ voltage
relationship of a PN junction which is temperature sensitive, so a
temperature compensated circuit should be used.
What you are trying to do is make the CdS response match (exactly match)
the Selenium meter.
Now ideally the Selenium cell would be operated as a current source so
I = C . L
However this is not the way the Rolleiflex (and other cameras) use it.
Instead they are using it as a voltage source. In this case
V = D . log ( E . L)
where C, D, E are constants.
So in short, get a hand held meter. They are cheap, accurate, and useful.
Leave the Rollei alone, you might wreck it.
Richard Urmonas
Date: Wed, 10 Jan 2001
Tim O'Connor wrote:
Obvious refinement:
Get a "snap on" lens cap, and make a hole in that for the
ping pong ball. Easy to mount, and lower cost as well (I
think).
Or, frost (sandblast, paint with opaque white paint) a UV
filter.
Or, point the camera towards the light and subtract two f
stops. Don't aim at the sun, tho' - makes nasty holes in
cloth shutters.
--
Date: Wed, 10 Jan 2001
or just get a piece of white plastic and hold it in front of the lens. i
saw adams do that in a video, but with a pentax meter, instead of an slr.
bob
Date: Wed, 10 Jan 2001
ambient light measurements can't be simulated with a reflected light meter
(even a spotmeter), and mostly eliminates many metering hassles and
decisions, so much preferred by many of us (esp. in handheld meters etc)
others have used a free coffee lid (frosted plastic) from 7/11 stores etc.
about the right size...
also thanks to Dante S., I have learned of a plastic variant that has a
rubber oring pair that instantly zip in and out of a filter thread, so you
don't have to screw the adapter in, just pop it in/out
finally, the Wallace Expo disk is another nifty plastic adapter for series
VII threads (IIRC) which can be used to convert for ambient light readings
(and preflashing in darkroom see
http://www.smu.edu/~rmonagha/mf/preflashing.html)
regards bobm
[Ed. note: possible source of selenium meter cells?]
[1] The super ikonta B allowed 11 exposures per 120 roll.
The BX model allowed 12. From what I have read, the
12 frames on the BX may have been a mistake; the
advance mechanism never had the precision of a
Rollei, and overlapping frames could be a problem
even when new.
[2] I have never dealt with, and have no connection to:
http://www.goldenapple.com/wwr/
However, they advertise meter cells for the Super BX.
From Rollei Mailing List;
Don't worry : hand-held meters are alive and well, even if your local
store does not stock them (does your local store stock second-hand
Rolleicords ? ;-)
To have an idea of the offer you can check this 100% Europe-oriented
list of web sites :
http://www.gossen-photo.de/uk/produkte/index.htm Gossen meters, Germany
http://www.megatron.co.uk/euromaster2/index.html for the
Weston-selenium-classical
There are of course several other brands including Russian/Ukrainian.
Any good mail order shop in Northern America will supply a wide range
of exposure meters. Selenium meters are still on the market. There are
even some very small ones. Whatever the technology inside (selenium,
CdS, Silicon) I would in any case recommend to buy a meter equiped
with a white diffusing attachment to allow incident light reading.
Those shaped like a half sphere sliding aside when not in use
(impossible to lose) are nice. Beware if you buy a second hand
non-selenium meter that they might require a kind of mercury battery
gradually phased out of the western market. The RUG list in this case
will provide you with all the information to solve this widely
discussed 'mercury' problem.
I myself have a Weston ; eventually I bought a Gossen meter for flash
metering.
--
From Rollei Mailing List;
[email protected] wrote:
For oldish selenium cell meters Bob Schwalberg once told me
that if they fail there's a good chance the problem is the connection
wires. By pushing your thumb on the cell and turning slightly
you can clean the contacts with friction. Sometimes the meter
begins to work again. In your case it worked. Ed
From Rollei Mailing List:
[email protected] wrote:
Let's see. In bright sunlight it's f/16 at the reciprocal of the
film speed. Tri-X Pan would be 1/400 sec. 1/500 is close enough.
Then, shutter speed is longer and aperture wider as the sun goes
down and/ or the clouds appear. Etc. A handy guide is the Harris
Memory Meter from Bob Harris, an ex-Kodak guy. P.O. box X,
Rochester, N.Y. 14617. Bob was a classmate of mine at RIT back
in the 1950s. I'm not sure what he sells the guide for. Haven't
seen him in years. Ed
From Contax Mailing List;
Back in the 70s Topcon made a really nice incident dome which was mounted
on a filter ring and screwed into your lens so you could use the camera
meter for incident metering. I haven't seen one in years.
There is a man who makes them now, but his are flat like ordinary filters.
This works, but isn't ideal.
Bob
From Leica Mailing List;
When photographing BLACK, what you are photographing is the reflections
off of the surface of the black object. Otherwise there is no detail to
photograph. Black is black. Zone zero. When you look at black, you only
see the reflections off of the black object. If it coated with soot, well,
it will be tough to see and tough to photograph. Soot does not reflect
much light. But a shiny black cat coat does.
If the cat has a shiny coat, you will be photographing the shine, not the
black. The black will be just that. Black. Clear film (neg) black film
(pos). Zone 0.
So, when metering a black cat (the cat, not the background,) your
reflected meter will be fooled and will give you an 18% gray (zone 5) cat.
This is not what you want. You want a "black" cat.
Read the black cat and stop down 1-1/2 to 2 stops. This will keep the cat
black and record the reflections (shine) off of the coat. Simply reset the
ASA dial on your M6 to a higher film speed.
Do not open-up. The meter produced 18% gray cat, will turn white.
If you use flash, the flash will produce some reflections. But you should
set the ASA on the auto flash dial to a stop or two higher than the film
ASA in the camera. Same on the camera dial for TTL flash.
Keep the cat black. Don't let your reflected meter or reflected reading
flash be fooled. Stop down via ASA control.
An incident meter will produce a pretty good exposure as it is reading the
light falling on the cat, not the cat. So it is not fooled by the black.
It will put the black cat in the black part of the gamma curve (probably
zone 1) and allow the reflections (shine - zone 6 or 7)) to be recorded on
the film. Some reflections may be specular zone 10 (really shiny cat.) An
incident meter will put everything where it is supposed to be as it is
blind to subject failure. So will/is an incident flash meter. Gossen Luna
Star F2 or Gossen Luna Pro Digital-F.
Just like reflected meters are fooled by snow scenes, they are fooled by
black scenes. Open up for white, close down for black.
Jim
From Hasselblad Mailing List;
[email protected] wrote:
I have numerous meters. Pentax Digital Spot modified by Zone VI. A Sekonic
Studio Deluxe (my batteryless backup), a Gossen Luna Star F (wonderful
incident and flash meter), and a Gossen Luna-Pro Digital (no flash). The
two Gossen meters have exactly the same display and features as well as
use. But the Luna-Pro Digital is easier to carry, has a 25 degree
reflected capability, and incident capability albeit not as convenient as
the Luna-Star-F. Both meters give exactly the same incident reading under
identical circumstances. But the Luna-Pro is much better at reflected
readings.
My Hasselblad 203FE has a built-in meter that also agrees with the
Luna-Pro reflected readings. But the prism meter on my 503CW is not very
good with respect to my other meters. There is sometimes up to 1.5 stops
difference.
I've personally found the Gossen Luna-Pro Digital meter to be the best all
around versatile and accurate meter available.
Jim
From Hasselblad Mailing List;
Note : in the US the Lunasix F is sold under another name : Luna-Pro.
I myself have the Lunasix F.
'F vs. 'Pro : probably no difference in terms of reliability. Ease of
use : both use the same "slide rule" control dial plus the
"zeroing+memory" measurement. Probably the most practical system if
you like analog read-outs.
The 'F is substantially cheaper than the 'Pro ; in the 'F you get both
ambient *plus* flash in the same unit as standard. And you can add to
the 'F: tele (a kind of "wide" spot-meter), repro, darkroom,
microscope, fibre-optic attachments common to various Gossen meters.
On the 'Pro you have to buy the flash-meter attachment extra.
As an amateur, my Lunasix F serves 110% ;-) of my tasks. I do not miss
the spot feature (I mostly use incident light readings) and I know can
eventually buy the tele attachment. I can hardly believe that you'll
find a difference at the ordinary user level between CdS and Si-SBC
except for very low light levels, that kind of long exposures used for
astronomy or microscopy.
Second-hand Lunasix F models turn up frequently in excellent condition
in the the 150 Euro range of prices. My understanding is that people
are moving to meters with digital readout LCD displays for various
reasons, so it might be a good opportunity to buy a Lunasix F now. To
be complete I should mention that the classical CdS Lunasix
(non-flash) is less interesting, IMHO, since there is no possibility
to add a flash meter, and it does not use the zeroing measurement but
a more "antique" system of 2 scales like in the Weston.
If you get a 'F or a 'Pro, being myself an ever-ready-case addict, I
would recommend to try and find the folding hard leather case,
'old-style' which opens like a Rollei-TLR ever-ready case, and is much
more practical than the soft leather zipped pouch now supplied as
standard.
--
FRom Hasselblad Mailing List:
kwow wrote:
The Lunasix-F does not use a CDS cell. It has a Silicon Blue cell, the
same as is in the Profisix.
There is absolutely no difference in build-quality or reliability between
the two. They differ in as far as:
a) the Lunasix F does flash as well, the Profisix needs an attachment to
do that;
b) the Profisix takes more attachments, and the ones that will not fit the
Lunasix F as well (Profi-Flash, Profi-Spot, Profi-Color, Profi-Flex
(though there is a Flex attachment that will fit the Lunasix F) and
Profi-Lux) are plugged directly into the Profisix's electronics, so no
dialing in of correction factors is required;
and finally c) the Profisix is a bit more sensitive: it meters down to EV
-4 while the Lunasix F stops at EV -1 (at ISO 100).
From Rangefinder Mailing List;
Lee Lockwood wrote:
Did you mean an 18% gray card?
The rule I've heard is "meter off your hand, then add a stop" because
the hand reflects about one stop *more* than what reflectance meters
expect.
However, I read on a site recently that meters are calibrated for 13%
and *not* 18% as is commonly believed. So a caucasian reflecting twice
that would have about 26% reflectance, about matching the 28% quoted
above.
Bottom line: A meter calibrated to 28% and a corresponding gray card
should match caucasians well.
Like you, I use a Seconic to avoid this whole issue.
Also, I've simply memorized the EV's for common light-situations,
and rarely meter at all. Here's a list:
The ones with '*' are those I use most often.
Mark, who needs to get back to work
From Hasselblad Mailing List;
Bill Grimwood wrote:
I replaced my Gossen Luna Pro F with a compact and light Gossen Luna Pro
digital. Loved it but then got the Gossen Luna Pro F which looks just like
it but does flash also. A light meter should be light!
It weighs 8.5 ounces with it's one AA battery. No weird batteries!
Having a meter which does not weigh down a top pocket and has: SBC Silicon
Photodiode Ambient compact lightweight low light reading ev -2.5 to +18 at
ISO 100 angle of coverage is 25 degrees reflected and 180 incident is
really nice.
Works in low light night situations unlike a spot meter or a Selenium
meter but will also do flash.
Sometimes ill take a reading off what seems like a good middle grey and
then turn around and flip the incident dome over the sensor and check it
against the incident reading. Satisfying as it is often a match up!
When i use it with the hasselblads I use it often in EV mode! LOVE that!
I also have a Pilot 2 Selenium Meter which will fit on a hot shoe and has
the same insides I'm pretty sure as the meter in my meter knob which i use
more often. But both i don't trust so much for indoors it is only good
down to ev +5 if that. I add a stop to those lower light readings and they
come out OK. The knob only gives you EV numbers. But the pilot does not
have EV (the old ones did).
I put the meter knob on when I'm taking off all day with just a camera
with a lens, usually the 80 as the 50 is just too darn heavy! ANd the
folding finder which is also not too heavy.
Mark Rabiner
Date: 18 Jun 2001
These may be of interest to some of you.
Chart 1: Shutter Speeds at EV & Aperture
http://users.ev1.net/~dbdors/Photography/ev_table.html
They are available as downloadable Excel spreadsheets or Text files here:
http://users.ev1.net/~dbdors/Photography/Photography.html
May the Light be with you.
-----
From rangefinder mailing list:
Date: Fri, 21 Sep 2001
From: "Jeffery Smith" [email protected]
Subject: RE: [RF List] Light Meters [Was: Speaking of Kievs]
Subject: RE: [RF List] Light Meters [Was: Speaking of Kievs]
I just buzzed around Adorama, and they have a "Black Cat" light meter
for $18.95 and some other "house brand" Ador meters.
Anyone ever see one of these?
...
From Camera Fixing Mailing List:
Date: Tue, 29 Jan 2002
From: Ron Schwarz [email protected]
Subject: Re: [camera-fix] Weston Master iV Fix
> Then I placed it under the sun for a short while to "energize" the CdS cell.
Weston Master meters use selenium photocells. A cadmium sulfide photocell
is photoresistive (it needs a battery, and its resistance varies according
to the amount of light falling on its surface). A selenium photocell on
the other hand operates by converting light to electricity. The more light
that falls on it, the more electricity it will create. I would recommend
against leaving it in full sunlight, because you are forcing its maximum
output into the delicate magnet wire in the galvanometer. If there is
enough current (i.e., enough light) over a long enough period of time, it
is possible to damage the meter movement.
As to the practice of "energizing/rejuvenating" cadmium sulfide cells, the
jury is out, and the majority of the techs I've heard from do not give it
any credence.
The biggest killer of selenium photocells is humidity. Weston coated their
cells, which is why you'll sometimes find examples pushing 70 years old
still working fine with the original cells. You'll also find relatively
new models (i.e., Master V) with dead cells, most likely due to flaws in
the surface coating that allowed atmospheric moisture to get in and ruin
the selenium layer.
From Rollei Mailing List:
Date: Wed, 30 Jan 2002
From: Ron Schwarz [email protected]
Subject: Re: [camera-fix] Weston Master iV Fix
> I have two Master II and you have given me the spur to try fixing
>mine. Any more words of wisdom regarding the Weston's?
The early models use a variety of proprietary reverse-spline-head screws.
In practice that means *carefully* cutting a slot to allow you to use a
standard driver bit to remove and replace them.
> Does anyone have a clue where to buy the "Invercones" for these?
Ebay, or perhaps Megatron.
From: william martin [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Light Meters: Incident vs. Reflective
Date: Tue, 12 Mar 2002
"Q.G. de Bakker" [email protected] wrote:
> william martin wrote:
>
> > Ansel Adams encouraged polaroid shots to preview exposure and composition
> results.
>
> Did he? Composition results i can understand, but exposure...?
Yes, he did. He was very enthusiastic about it.
> I have been using polaroid for a long time, and think it is a dreadfull
> method of checking exposure. I can't think what good the "master of subtle
> tones" may have seen in this...
I've always found Polaroid film to have pretty good tonal values, and found
the method useful for fine-tuning my exposure. I wouldn't use it as a
substitue for a good meter, but it can pick up a lot of the little hot spots
and too-dense shadow areas that many people tend not to see, for some
reason, when they look at a scene. Adams, though, also used it ( he said ) even
for portrait work. I've never tried that.
Incidentally, I once found an interesting "variation" of the zone system on the
web somewhere. Wish I could remember the guy's name, I forgot to
bookmark the URL, and he did absolutely beautiful B&W work, capturing very
subtle tones. His method was simple: measure "the" key element in
a scene with a spotmeter. If that element was supposed to be light gray,
increase the exposure 1 stop. If it was to be a highlight, increase 2 stops.
Going the other way, if it was to be a light, detailed shadow, decrease 1 stop,
and decrease 2 stops for a dark shadow with some detail. No
processing compensation, and once you select the key element, let everything
else just fall where it may. Sounds too simplistic, but if his work
reflects the method, he sure got nice results. I have a feeling he must have
done a lot of compensation during the printing phase, but he didn't say
that. His discussion was mainly about using the in-camera spotmeter on the
Pentax cameras. Someday I'll try his method, but haven't so far. What it
made me think is that maybe we "guild the lily" by following the zone system
approach too closely, i.e, maybe there's a lot more detail in the zone
system than can be accomodated by the film/developing/printing/ etc. Looking at
it another way, maybe the zone system as, written down, is
overkill? I do know that I leave out a big chunk of it -- I don't calbrate the
film speed for my cameras and lenses. I almost always start with the film
manufacturer's specifications and make changes that I feel are necessary, based
on the results. I feel like Kodak, Ilford, Agfa, et. al. spend millions
of dollars doing research to determine the characteristics of their films, and
I'm not likely to improve their results appreciably by doing my own
experiments with the money I'm willing to spend on it. What the heck, it saves
me money and I'm satisfied with my results, so .....
From: "roland.rashleigh-berry" [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Light Meters: Incident vs. Reflective
Date: Fri, 8 Mar 2002
An incident light meter is better than a reflected light meter because it
measures light falling onto your subject rather than light reflected off it
and this gives a better exposure reading. If you use reflected light then
the light reading is affected by the tone of your subject. A white subject
will reflect much more light than a black subject and so the light reading
for the white subject will be higher and yet if they are both under the same
lighting conditions then the exposure should be about the same. With an
incident light meter you don't have this problem.
"DarrenH" [email protected] wrote
> How exactly does an incident light meter differ from a reflected light
> meter, and what are the advantages/disadvantages?
>
> I appreciate you input...thanks! D
From: [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Light Meters: Incident vs. Reflective
Date: Fri, 08 Mar 2002
"roland.rashleigh-berry" [email protected] wrote:
>An incident light meter is better than a reflected light meter because it
>measures light falling onto your subject rather than light reflected off it
>and this gives a better exposure reading.
On the other hand, an incident light meter can't tell you what the contrast
range of your subject is. You might get perfectly exposed midtones but
completely blown highlights and no shadow details.
I wouldn't classify either type as being "better." They're different.
An incident meter reads the light falling on it (and presumably falling on
your subject.) A reflected meter measures the light reflected off your
subject. Guess what you're photographing? The light reflected off the
subject. Not the light falling on it. :)
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Light Meters: Incident vs. Reflective
From: "Tom Thackrey" (no email)
Date: Fri, 8 Mar 2002
"DarrenH" [email protected] wrote:
> How exactly does an incident light meter differ from a reflected light
> meter, and what are the advantages/disadvantages?
Incident meters measure the light source. Used properly, this means the
light falling on the subject. The reflectivity of the subject is not a
factor in the meter reading so you don't have to adjust the exposure because
the subject is lighter or darker than average. The disadvantages are that
you may not be able to get to a place where you can measure the light
falling on the subject and you many want to know the range of values
reflected by the subject(s).
Reflected meters measure the light reflected by the subject. All in camera
light meters are reflected meters. The main disadvantage is that they
require that you adjust their readings when the subject is darker or lighter
than average. For example an uncorrected exposure of a snow scene will come
out gray instead of white, likewise a black cat on a black background will
also come out gray. Used properly, that is measuring the light reflected by
the various elements of a scene and deciding how you want to capture those
values, a reflected meter can give you the best possible exposure value for
a scene.
Date: Fri, 08 Mar 2002
From: Gordon Moat [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Light Meters: Incident vs. Reflective
Just to add to the great comments, here is a nice visual display of this
comparison:
http://www.sekonic.com/BenefitsOfIncident.html
A picture can be worth a thousand words, but how many words are worth a
thousand pictures?
Ciao!
Gordon Moat
Alliance Graphique Studio
http://www.allgstudio.com
From: Bj�rn Nilsson [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Need advise for starters.
Date: Thu, 07 Feb 2002
What Roland is refering to as "no light meter at all" would be the
"sunny 16" rule. I.e. during the "full light" hours of the day, the
exposure would be 1/film ISO at f/16 when the unclouded sun lights the
subject. If it is very cloudy and you cannot see the sun at all it
would be 1/film ISO at f/5.6. You have to work out the in betweens
yourself. A good way of determing this is to look at the sharpness of
the shadows. A sharp shadow means f/16 while a fuzzy shadow means more
like f/8. If you hardly can see any shadow at all it is f/5.6.
Anyhow, trying to work without a light meter is very good pratice, as
it makes you look at the light. After all, the light is the main
source of everything we do in photography. But this doesn't say that a
light meter isn't needed. I just want to point out that trying assess
the light *before* picking up the meter may give you better pictures,
as this made you take a closer look at the subject.
Before deciding on a light meter, think about your photographic future
for a while. If you think that you possibly want to do some more
elaborate lightning in a studio, you should maybe consider a meter
with flash metering capability. Else almost any decent meter with
incident (opal sphere) metering will do. Metering the light that hits
the subject is easier than metering the reflected light from something
"middle gray". Normally you just turn your back to the camera and
press the meter button for a correct value. On many meters you switch
the metering modes by simply sliding the opal sphere over the metering
cell.
//Bj�rn
...
From rollei mailing list:
Date: Fri, 12 Apr 2002
From: Laurence Cuffe [email protected]
To: [email protected]
Subject: Re: [Rollei] Incident Only Meters
Date sent: Thu, 11 Apr 2002
From: Bob Shell [email protected]
Subject: Re: [Rollei] Incident Only Meters
To: [email protected]
>John Hicks at [email protected] wrote:
>
>> I remember that from Topcon a couple decades ago but nothing since.
>
>Me too. I had one of the Topcon ones at one time. I haven't seen a
>properly hemispherical one since, although using a hobbyist's vacuum forming
>machine you could certainly make them. Scale modelers use these machines to
>make clear cockpit canopies and other things. Just find some translucent
>white plastic, cut a ball in half to make your mold, and go to it.
>
>Bob
Would it be naive of me to suggest a table tennis ball and a craft
knife as a solution?
all the best
Laurence Cuffe
From rollei mailing list:
Date: Fri, 12 Apr 2002
From: Richard Knoppow [email protected]
Subject: Re: [Rollei] Incident Only Meters
you wrote:
>I looked to the Sekonic L 398. Looks nice with the large dome. I guess that
>the EV range is limited due to the limited sensitivity of the Selen cell?
>
>Is there a difference in performance on the use of meters for incident
>light which have different sizes of the domes?
>
>I.e. the large dome of the Sekonic and the small of the Gossen?
>
>
>Dirk
I have both meters. The readings are the same, I mean exactly the same. I
use the Gossen Luna Pro as a standard to check other meters. I also have a
couple of older meters which are in good condition, a GE PR-1 with the
incident light adaptor, a Weston Master II, and a GE DW-68. All argree
within reasonable error.
The PR-1 is the least sensive, the Sekonic just a little more and the
Weston the most sensitive of the Selenium meters.
I also have a Sangamo-Weston meter but its cell is flat and it isn't
worth what it costs for a new cell.
I also have an original Norwood Director. In perfect cosmetic condition
but its cell is also flat and would be quite expensive to replace since the
Sekonic cells are not interchangible.
BTW, the Sekonic and the Luna-Pro give me identical reflected light
readings. The Weston is tricky since it has a very wide angle of
acceptance. I've also come to the conclusion that Weston had a safety
factor in its speed system. The weston meter tends to underexpose. BTW the
setting for Weston Speeds is one number less than the ISO speed. I.e., for
film rated ISO-100 set the Weston scale for 80.
Another suggestion from bitter experience: Don't keep the Sekonic
accessory fittings in the case. The pocket in the cases I've seen are not
very secure and the parts will fall out and get lost. All are available but
are expensive.
----
Richard Knoppow
Los Angeles, CA, USA
[email protected]
From rollei mailing list:
Date: Fri, 12 Apr 2002
From: Bob Shell [email protected]
Subject: Re: [Rollei] Incident Only Meters
Laurence Cuffe at [email protected] wrote:
> Would it be nieve of me to suggest a table tennis ball and a craft
> knife as a solution?
> all the best
Well, the story goes that this is exactly what Don Norwood did when he
invented the incident meter.
I was thinking you would want a larger diameter hemisphere if you were going
to screw it onto a lens for TTL incident metering. I have heard of people
using styrofoam cups, as well.
Bob
From rollei mailing list:
Date: Fri, 12 Apr 2002
From: [email protected]
Subject: Re: Re: [Rollei] Incident Only Meters
you wrote:
>I looked to the Sekonic L 398. Looks nice with the large dome. I guess that
>the EV range is limited due to the limited sensitivity of the Selen cell?
>
>Is there a difference in performance on the use of meters for incident
>light which have different sizes of the domes?
>
>I.e. the large dome of the Sekonic and the small of the Gossen?
I use both. There seems to be no real difference in results between the
small and large domes. The Sekonic is more versatile and easier to use as an
incident meter, IMHO. The Luna Pro is more sensitive under low light
conditions. However, the Sekonic usually reads as little available light in
which I am likely to be making photographs, anyway.
Allen Zak
From rollei mailing list:
Date: Fri, 12 Apr 2002
From: Bob Shell [email protected]
Subject: Re: [Rollei] Incident v. reflective
Kotsinadelis, Peter (Peter) at [email protected] wrote:
> In answer to your first paragraph it depends on what film you are using.
> Velvia is not ISO 50 but between ISO 32 - 40. When I set my ambient meter
> I set it as ISO32 and its works perfect. For my camera ISO40.
> I too did this once using the ISO50 with ambient meter and pictures were
> dark.
Velvia is, in fact, ISO 50. There are very strict standards and procedures
for determining ISO speeds. The fact that many photographers like the
results better when they rate it at 40 or 32 does not change that. When you
set your camera to a number other than the rated ISO number that is not an
ISO speed but an EI, Exposure Index.
> The .5 stops difference can be attributed to the gray card. Although all
> claim 18% I have seen a slight variance between alleged gray cards.
>
The Kodak Gray Card is manufactured to incredibly tight standards and is
precisely 17.8something in reflectance. I don't recall the exact number,
but they have it specced very precisely. The only time a Kodak Gray Card
will have a different reflectance is if it has faded from being left exposed
to light. It is a good practice to replace them ever few years.
I'm not sure what .5 stop difference you are speaking of above, but the
difference between a gray card and standard reflectance to which meters are
calibrated is .5 stop, the difference between 12.5% reflectance and 18%.
This is why the Gray Card instructions tell you to make a half stop
correction from your reading off the card.
> Last, the 1/3 stop for reflective meters is consistent with what I have
> found as well. It may seem odd but perhaps the camera makers are
> adjusting the meter to be slightly more overexposed. For this reason
> when I am not with meter I use a variation of the Sunny 16 rule.
> I set the shutter to the next higher speed for a given ISO and use F11.
> The reason for this is that is allows for about a 1/3 - 2/3 overexposure
> compared to the Sunny 16 rule. It also accounts for shadows.
>
Generally point and shoot and low end SLRs are set to overexpose on the
theory that they are being used with color negative film. Pro cameras are
usually set up for proper exposure on transparency film.
> Even meters side by side can give slightly different readings. I have a
> Sekonic L328F and L508. Side by side in the same light the difference
> between the two can be 1 to 2 tenths of a stop. Now before someone says
> I need to have them calibrated, let me say I already did just that.
> Apparently there is a slight tolerance when adjusting them.
Yes there is an adjustment tolerance, but you should never see more than
about a tenth of a stop difference.
Bob
From rollei mailing list:
Date: Sat, 13 Apr 2002
From: Bob Shell [email protected]
Subject: Re: [Rollei] Incident v. reflective
[email protected] at [email protected] wrote:
> I read in most literature, that the factory calibration should be for 18%,
> so there are the grey cards with 18% for compatibility. However, Bob, I
> must mention I did NOT read your book.
Most literature is just plain WRONG about this.
>
> It is really the first time that a hear about the compensation needed for
> the 18 % grey card. However, I am a fist time grey card user....
> Again the question: Could it be that the "half step compensation" is
> already calculated within the calibration of my Rolleis and that it is not
> for the Gossen?
I was hired by Kodak. I wrote the instructions for the Kodak Gray Card.
The standard of 12.5% for meters has been in place since the 1950s.
Bob
From rollei mailing list:
Date: Fri, 12 Apr 2002
From: "R. Peters" [email protected]
Subject: [Rollei] Incident meter dome for any TLR
There was an article in (maybe) Popular Photography probably 20 years ago
about making a "Topcon" style incident meter dome for any SLR. In most US
Grocery stores, Nylon Stockings for women are sold under the "L'eggs" brand
in an "egg-like" plastic container made in 2 parts. Half of that L'eggs
container makes a Jim-Dandy Incident light meter dome when glued into a
49mm (or whatever) to 67mm step up ring. The author said it worked
great. But never got around to making one. Maybe it was the thought
of going into a grocery store to buy a pair of womens' nylon stockings!
bob
From rollei mailing list:
Date: Sat, 13 Apr 2002 13:15:47 -0700
From: Richard Knoppow
From rollei mailing list:
Date: Wed, 10 Apr 2002
From: Richard Knoppow [email protected]
Subject: Re: [Rollei] Incident Only Meters
you wrote:
>Hi Folks!
>
> I was just reading in Norman Sanders 'Photographic Tone Control'
>about cutting out a graycard and putting it in the lenscap for
>the handtype spotmeters and using the meter to read the greycard
>cap to simulate incidence lightreadings. I'll try it since I've got
>the Pentax Digital Spotmeter but no incident. But, is it really
>the same as a good incident meter. I've seen some of the
>Hollywood type incident meters they used to use and maybe
>still do, I forget the brand name, but they have different
>accessories available for them. These are incident only
>meters. Anyone use these type of meters or have used them?
...
The meter you mean is probably the Spectra-Combi. It is actually the
original of the Norwood Director meter and works the same way. The Norwood
meter is currently made by Sekonic.
The Spectra version is larger, in a square case with a larger photo-cell.
The original had only a Selenium cell but later a semiconductor cell, I
think Cds, was added for low light level capability. The name Combi is for
the type with both types of cells.
The meter has three fittings for the photo-cell. A hemispherical
diffuser, a flat diffuser, and a perforated disc. The hemispherical
diffuser is used for most readings. It is pointed at the camera from the
subject position. Supposedly, the light striking it will integrate in the
same way as the light striking the subject.
The flat disc is used for incident readings of single sources. Its useful
in determing lighting ratios since measurements can be made without turning
the lights on and off.
The perforated disk is used for reflected light readings, mostly to
determine subject contrast.
The meter has a slot for light attenuators. The Spectra meter came with a
set of slides for various film speeds and shutter speeds to make the scale
direct reading in f/stops. Normally, it has a high and a low range using a
single slide which is either in or out.
The Norwood Director and current Sekonic meter works the same way. I
believe Sekonic offers a set of slides for direct reading, at least they
used to.
The Sekonic meter is a good one for general use, quite accurate. It also
operates without batteries so makes a good backup to other meters or
built-in meters.
I can make out a good argument on both sides regarding reflected light
vs: incident light measurements. Both systems make assumptions about the
reflectivity of the subject and contrast of the scene. One must have some
idea of what the reproduced scene is supposed to look like. Either type of
meter may give a false indication of exposure where ligting or scene
contrast is extremely high or low. The use of a meter which allows actual
measurement of lighting and brightness ratios is quite useful even if the
Zone System is not being used. For instance, suppose I am shooting a very
low key scene. I may want to base the exposure on the highlights I want
detail in even though they may be a small part of an otherwise dark scene.
A reflected light meter will try to expose for the bulk of the scene and
far overexpose it. The incident meter will give a more reasonable value,
provided its used at the subject position. I can get an accurate reading
with either type of meter by means of the technique of using it.
----
Richard Knoppow
Los Angeles, CA, USA
[email protected]
Date: Thu, 11 Apr 2002
From: Bob Shell [email protected]
To: [email protected]
Subject: Re: [Rollei] Incident Only Meters
Rich Lahrson at [email protected] wrote:
> I was just reading in Norman Sanders 'Photographic Tone Control'
> about cutting out a graycard and putting it in the lenscap for
> the handtype spotmeters and using the meter to read the greycard
> cap to simulate incidence lightreadings. I'll try it since I've got
> the Pentax Digital Spotmeter but no incident. But, is it really
> the same as a good incident meter. I've seen some of the
> Hollywood type incident meters they used to use and maybe
> still do, I forget the brand name, but they have different
> accessories available for them. These are incident only
> meters. Anyone use these type of meters or have used them?
You could cut out a piece of Gray Card as described. If you angle it
correctly and make the necessary half stop correction it should give you the
same results as an incident meter in most cases.
Hollywood types use Spectra and Sekonic meters, incident meters with big
domes.
I use incident metering almost all the time.
I'm co-author of The Hand Exposure Meter Book, which is the only current
book on the subject. I also wrote the instructions for the Kodak Gray Card
when it was revised in 1999.
Bob
From rollei mailing list:
Date: Thu, 11 Apr 2002
From: Bob Shell [email protected]
Subject: Re: [Rollei] Incident Only Meters
John Hicks at [email protected] wrote:
> Just buy a Wallace Expo-Disc that fits the spotmeter; they're available
> from B&H etc. It's a diffuser disc that transmits 18%.
>
> John Hicks
> [email protected]
And doesn't work!
It's flat. If your subject is flat, it will work just fine. If your
subject isn't flat, then it doesn't work. You need a dome for proper
integrated readings, like the ones Topcon used to make in filter rings to
fit on their SLR lenses.
I argued with George Wallace about this, as did Roger Hicks, and we both
came to the conclusion that he simply did not understand metering or
sensitometry.
Unfortunately, we can't ever bring him around on this since he died last
year.
Bob
From rollei mailing list:
Date: Thu, 11 Apr 2002
From: Bob Shell [email protected]
Subject: Re: [Rollei] Incident Only Meters
Jerry Lehrer at [email protected] wrote:
> Yes, but a while back I saw a diffuser hemi-sphere that came in
> screw-in filter sizes that claimed to be far superior to the disc
> type. Unfortunately I lost their web site due to a computer change.
> Does anyone know where I can locate that source?
I'd like to know that, too. A hemisphere is the proper shape since
the diffuser acts as a surrogate subject. I remember back in the 70s
Topcon had them for use on the Super D cameras. Since the camera had
a meter readout on top as well as in the viewfinder, this made the camera
into a very convenient incident meter. Hasselblad has a prism finder with a
small incident dome on it, which is said to work well.
But flat diffusers, like the Wallace thing, are only good for photographers
who live in Flatland.
Bob
From rollei mailing list:
Date: Thu, 11 Apr 2002
From: John Hicks [email protected]
Subject: Re: [Rollei] Incident Only Meters
you wrote:
>But now my problem:
This is _normal_! There are manufacturing tolerances, adjustment
tolerances, different opinions about what a meter should be calibrated to etc.
Here's how I deal with it. Bear in mind that there may be differences of
opinion but my calibration methods result in the same density on film,
which is what counts.
First of all, all incident-light meters are adjusted to read Sunny f16.
That's 1/EI @f16 for full sunshine with the meter held vertically (cell
pointed straight forward) but oriented in the direction of the sun. That's
here in a temperate area; if you're in the far north or the tropics you'd
probably need to use a different standard.
Second, all reflected-light meters are adjusted to Sunny f16 reading a
Wallace Expo-Disc aimed toward the sun in the same conditions. The
Expo-Disc is a flat diffuser disc that fits over a lens, meter cell etc and
transmits 18%
There's some debate over whether 18% or 13% is or should be the standard
but in this case that's immaterial; film exposed according to either type
of meter reading results in the same density, within a reasonable error.
If a meter has an adjustment screw (_not_ a zeroing screw) then the meter
is adjusted directly for Sunny f16; if not then the EI setting is changed
until Sunny f16 is indicated. That is, if the assumed EI is 1/125 @f16 for
an EI 125 film and the meter needs to be set to EI 80 in order for it to
read 1/125 @f16, then in the future all EI settings on that meter are given
a +2/3 stop correction factor, or vice-versa if the reading is off in the
other direction.
The point is that we don't care what each meter says in comparison to
others when they're set to a manufacturer's-designated EI setting because
we've now developed a correction factor for each meter _so they all say the
same thing_.
John Hicks
[email protected]
From rollei mailing list:
Date: Thu, 11 Apr 2002
From: Bob Shell [email protected]
Subject: Re: [Rollei] Incident Only Meters
John Hicks at [email protected] wrote:
> I remember that from Topcon a couple decades ago but nothing since.
Me too. I had one of the Topcon ones at one time. I haven't seen a
properly hemispherical one since, although using a hobbyist's vacuum forming
machine you could certainly make them. Scale modelers use these machines to
make clear cockpit canopies and other things. Just find some translucent
white plastic, cut a ball in half to make your mold, and go to it.
Bob
From rollei mailing list:
Date: Mon, 23 Oct 2000
From: [email protected]
Subject: Re: [Rollei] White Plastic over meter?
>From Jon, about the white Rollei TLR diffuser :
> ....Or is the mechanism for latching on to the camera something
> special, not to be duplicated?
No. Simply clip-on, very simple. The R-TLR diffuser will clip on all
R-TLRs equipped with a selenium meter either the un-coupled (E, T)
model or the coupled F model. When I do color slides with my R-T I
always switch to incident light reading with the diffuser to avoid
misreadings. But on the long term it might be a real challenge not to
loose this small item. Being an "ever-ready-caser" I keep the diffuser
at the right place in the front panel and up to now I never lost it.
So in fact any kind of soft or semi-soft white plastic with similar
diffusion/absorption properties will do the job. Hard plastic would
probably break too easily. But be careful to block any extra light
that could come on the side. So one should probably machine the inside
of a home-made plastic block like the real one to allow enough space
for the honeycomb cells without light leaks on the side.
-- Emmanuel BIGLER [email protected]
From nikon mailing list:
Date: Tue, 30 Apr 2002
From: "macthevorlon" [email protected]
Subject: Re: Color Slide Film (and not only)
>From memory:
FM/FM2/FM2n:
+ only: 1 f/stop or more overexposed, count clicks.
+ and barely 0: 1 f/stop overexposed.
0 and barely +: 1/5th f/stop overexposed.
0: in middle of deadband, proper exposure, 18% gray.
0 and barely -: 1/5th f/stop under exposed
- and barely 0: 1 f/stop underexposed.
- only: 1 f/stop or more underexposed, count clicks.
Mac
From rollei mailing list:
Date: Tue, 21 Nov 2000
From: Richard Knoppow [email protected]
Subject: Re: [Rollei] lens dust
you wrote:
>Hello all,
>
>I've been on a quest to find a cheap and useable Rollei TLR Planar/Xenotar on
>Ebay. Although a lot of stuff on E-bay is junk, I figured that something
>worthwhile must show up at some point. I've already sent back cameras twice
>due to defects. The latest I have acquired is a 3.5F type II Xenotar. It is
>in very good shape, with an excellent case and a plastic cap. The lenses are
>scratch free... but... the problem is that there is a lot of dust in the
>taking lens... throughout (not just on outer or inner surface). Also, the
>speeds are a bit off, as can be expected with these old cameras, as is the
>light meter.
>
>I have a few questions regarding this camera. 1. Will the dust in the lens
>interfere with picture quality? I've shot a test roll which looks okay,
>though there are dust specs on the negatives - would these be a result of the
>dust in the lens, or other dust in the camera, etc? Also, how difficult and
>costly is it to have the lenses cleaned out if I already plan to have a CLA
>done on the camera. Finally, regarding the light meter... is there any
way to
>repair or recaliborate it?
>
>Thanks in advance for any advice,
> David
The question about dust _inside_ a lens is: where did it come from?
This may be anti-reflection paint from the inside of the cell flaking off
or it may be some kind of fungus. You may be able to tell more by examining
the lens with a loupe and small flashlight.
Most lenses are fairly easy to open for cleaning. If the glass is OK
paint or actual dust can be blown out and the surfaces cleaned with lens
cleaner. Don't worry about centering, its done automatically by the design
of the lens mounting. The elements are sandwitched between two rings
which contact the glass only near the edges. Because the surfaces are
spherical this arrangement will automatically center the lens.
Mostly lenses have threaded retaining rings on the front. Often they do
not have slots or dots. These are removed by friction using a tube of the
right diameter with double-stick tape on the edges. Some Schneider lenses
have tiny set screws to hold the cell together. I've seen this on Rollei
finder lenses made by Schneider. It is sometimes hard to find them.
Cleaning the shutter is made more difficult because it needs to be
removed from the camera for a proper cleaning. In any case a fair amount of
disassembly is needed simply to get to it. Its better to send the thing to
H.Fleenor and get it overhauled. This is something that needs to be done
once in twenty years so its really not expensive. Harry can clean the lens
as well as tune up the camera. Good non-out-gassing flat paint doesn't seem
to be available anymore. The best I've found is Krylon Ultra-Flat Black
paint. It comes in spray cans but you can spray some into a bottle and
brush it on. It also works on element edges. Because it outgasses it needs
to be thoroughly dried (preferably baked at 150F) before assembling into
sealed areas. This is, BTW, a good anti-reflection paint for touching up
camera interiors.
The Rollei light meter uses a Selenium cell. They tend to loose
sensitivity in a non-linear fashion when they get old. Some cells last
seemingly forever, others seem to go quickly. Heat and moisture are the
enemies. The cells are supposed to be sealed to prevent moisture from
entering but the seals don't last forever. Because the fall-off is
non-linear the meter may seem to read right for low light levels and be one
or more stops low at high levels. The only fix is ot replace the cell. The
non-linear characteristic prevents simply adjusting the film speed ot
compensate.
My impression from this list is that the cells used in Rollei cameras
were made by Gossen and are no longer available.
If the meter doesn't work at all it may actually be fixable. That might
be an oxidized solder joint or contact somewhere, or a stuck meter due to
dirt in the bearings. Usually, when the cell goes bad it doesn't die, it
just gets inaccurate.
I don't know exactly what goes into making a Selenium cell. They were the
standard cell for lightmeters until transistor amplifiers became available
allowing the use of Cadmium disulfide and other variable resistance cells.
My point is that I wonder if there is anyone who could make cells for
Rolleis at a reasonable price. I am sure such information would be welcome
here.
----
Richard Knoppow
Los Angeles,Ca.
[email protected]
From Hasselblad Mailing List:
Date: Sun, 19 May 2002
From: Charles [email protected]
Subject: Re: [HUG] Light Meter
The analog Gossen LunaPro-F aka in the US as LunaSix-F
(with the cheap spot-meter attachment) has the advantage
of displaying an EV scale like that of the lens. Someone
on this list recommended it to me a while back and I now
say a prayer for them every night.
You can also get a cheap enlarger attachment for b/w printing
- a really nifty paper saver.
--
Charles MTgnin
http://www.theblueplanet.org
From Hasselblad Mailing List:
Date: Sun, 19 May 2002
From: Rick Rorie [email protected]
Subject: Re: [HUG] Light Meter
I couldn't agree more on the Gossen Luna-Pro F.
I've been using one for the last 16 years, and I couldn't have abused it
any worse if I hit it with a hammer daily. I like the fact that it gives
EV readings, and the flash exposures it recommends are spot-on.
-------------------------------
Rick Rorie
[email protected]
[Ed. note: I use the Luna-Pro F and both older analog and digital Pentax 1/21 spot-meters]
From hasselblad mailing list:
Date: Sun, 19 May 2002
From: Jim Brick [email protected]
Subject: Re: [HUG] Light Meter
As a "spot meter" goes, the Pentax Digital spot meter has the longest
history and best reputation. It can be purchased with a modification that
renders it insensitive to the color that it is looking at. This is
important because having a reflected reading that reads differently for
different colors is giving you skewed information.
I purchased a Pentax Digital spot meter perhaps twenty years ago and sent
it to Zone VI for modification. It is a marvelous meter. My daughter, who
is a photography minor in college, learned on this meter. She got married,
and moved out of the house last year, so my only hope of ever seeing my
meter again was to get her one. I found a "new" Zone VI calibrated (now
Calumet,) Pentax Digital spot meter on eBay, and got it for half of dealer
net price. We both now have our favorite meters.
If you want a spot meter, this is the one!
IMHO,
:)
Jim
From hasselblad mailing list:
Date: Sun, 19 May 2002
From: David Gerhardt [email protected]
Subject: Re: [HUG] Light Meter
"Ken Martin" [email protected] wrote:
> This may be inappropriate for this list, if so please accept my apology.
> This question is being driven by my recent purchase of Hasselblad
> equipment. Since this equipment does not have a built in light meter, I
> am planning a purchase of a spot meter. This equipment will be used
> primary for nature and outdoor photography. Any suggestions would be
> appreciated.
>
> Ken
Ken-
Over the years, I've used (and "accumulated") various brands, and models of
meters; primarily for use with my old 500c/m, or newer 203FE. These
included:
- Hasselblad "advance knob" meter (small & inconspicuous, but not very
"selective" or good in low light)
- Pentax Digital Spot meter (very accurate, includes "EV" settings for older
Hasselblad lenses... Unfortunately it was ONLY a spot meter. So I always
ended up carrying an additional meter as well)
- Gossen Luna Pro (Good accuracy {except at scale "switch-over"}, good
sensitivity, includes EV, mine took the old mercury cells)
- Sekonic Zoom Master L-508 (My favorite, overall. Takes a single "AA"
battery {no hunting for special "cells"}, includes a robust "incident" meter
"ball" that rotates for metering convenience, 1 degree-to- 4 degree zoom
"reflective" meter that allows you "TTL" accuracy for measurement & framing,
displays exposure in "shutter speed/aperture" or "EV", and includes a large,
legible Digital Display {with backlighting} for making readings under any
lighting situations. Moisture resistant, includes sophisticated
cord/cordless flash measurement, memory/averaging, tripod socket, PC socket,
programmable for 2 separate film speeds...)
As you can probably tell, I've "found happiness" with the L-508! Now I only
carry the single meter, and can do flash/incident/reflective readings.
Sekonic has an even newer version (L-608) that is more expensive (~$700),
and has features that may, or may not be of interest to the average
Hasselblad user (whoever that is). When I bought my L-508, I paid about
$400, and got a free book (Bob Shell) on exposure metering.
Any way, my recommendation would be an L-508 (even if you HAVE a meter in
your camera, like the 203FE). You'll have it a long time.
--
David Gerhardt
[email protected]
From Hasselblad mailing list:
From hasselblad mailing list:
Date: Sun, 19 May 2002
From: Jim Brick [email protected]
Subject: Re: [HUG] Light Meter
Dr. Elliot Puritz wrote:
>Jim: Regarding the Pentax modified meter; do you mean that the dial is
>modified, or that the entire meter is modified? I note that on Ebay often
>the seller will say "dial modified" and not comment on the meter itself with
>regards to what the meter "sees".
>
>TIA,
>
>Elliot
The meter internals. What it sees, and new reflection baffling. They also
put a zone system sticker on the meter dial.
Jim
From hasselblad mailing list:
Date: Mon, 20 May 2002
From: Rei Shinozuka [email protected]
Subject: Re: [HUG] Light Meter
FYI, from a 1991 zone vi catalog, here's what they listed as the
zone vi modifications to the pentax digital spot meter:
1. installation of superior photo-electric cells
2. installation of a series of step-down baffles to eliminate flare
3. installation of a broad-spectrum (ultra-black) infra-red absorbent
coating to eliminate reflections
4. design and installation of 4 corrective filters: the infra-red, ultra-
violet, and visual range packs are required to match the meter's
spectral response to the spectral response of the film. The filter
packs are not replacements; no existing meter contains _any_ corrective
filtration.
5. design and construction of tools and test equipment with which we can
calibrate your meter to within 1/6 stop of linearity over their range.
> From: Patrick Bartek [email protected]
>
> Jim Brick wrote:
> > Dr. Elliot Puritz wrote:
> > >Jim: Regarding the Pentax modified meter; do you mean that the dial
> > > is modified, or that the entire meter is modified? I note that on
> > > Ebay often the seller will say "dial modified" and not comment on
> > > the meter itself with regards to what the meter "sees".
> > >
> > >TIA,
> > >
> > >Elliot
> >
> > The meter internals. What it sees, and new reflection baffling. They
> > also put a zone system sticker on the meter dial.
>
> In addition to light baffles to reduce flare, a Zone VI modified meter
> had color correction filters added to balance the light sensitive cell
> to more closely match the color response of panchromatic film. The
> meter was also adjusted for linearity and calibrated.
>
> --
> Patrick Bartek
> NoLife Polymath Group
> [email protected]
--
Rei Shinozuka [email protected]
Ridgewood, New Jersey
From hasselblad mailing list:
Date: Mon, 20 May 2002
From: Jim Brick [email protected]
Subject: Re: [HUG] Light Meter
David Gerhardt wrote:
>- Pentax Digital Spot meter (very accurate, includes "EV" settings for older
>Hasselblad lenses...
David,
The number that you read in a Pentax Digital spot meter, even though
labeled "EV," is N-O-T an EV number. It is a "Light Value" number to be
used only on the meter itself.
If you set the meter ASA to 100, then the number actually matches a real EV
number and can be used on a Hasselblad. But at any other ASA, it is NOT an
EV number and CANNOT be used on a Hasselblad or any other camera that has
an EV scale.
Pentax did a disservice by labeling the number that the meter displays as
EV. It is NOT an EV number so never use it as such.
Jim
From hasselblad mailing list:
Date: Mon, 20 May 2002
From: Charles [email protected]
Subject: Re: [HUG] Light Meter
You use this attachment on the LunaPro-F (and other Gossen meters)
to measure the amount of light incident on the paper. Once calibrated
for the paper, it reduces the need to make test strips as you can zero
in on base exposure immediately. They cost about $25 used.
If you get one, make sure you tell the salesperson which meter it's for
(I think the LunaPro-F takes the SBC attachment, etc...).
I just don't know anything about density wedges.
Charles
From rollei mailing list:
Date: Mon, 27 May 2002
From: Richard Knoppow [email protected]
Subject: Re: [Rollei] Rollei 3.5 E Xenotar
you wrote:
>Jan
>
>I recommend that you keep using your hand-held Weston. if it is accurate.
>Unless new cells are available for the built-in or add-on Rollei meters
>they may be inaccurate.
>
>Maxwell screens are supposed to be the brightest, but I am wary of
>any screens that have the Fresnel element on the upper surface. Frankly,
>I like the Rolleiclear screen with RF prism.
>
>Please don't expect any offers of a Panorama Head until Friday (Marc's Law).
>
>Jerry
I second Jerry on keeping the Weston.
The main failure of Selenium cell meters is a loss of bright light
sensitivity. You can check the Weston easily. Set up a white card,
preferably large enough to fill the meter's viewing window. Illuminate it
so that it reads 50 on the _Low_ scale. Check the _High_ scale, it should
read exactly 50. If the cell is damaged the low reading will be higher.
What happens is that the high brightness sensitivity of the meter is
diminshed by a stop or more. The loss is non-linear so can not be
compensated for by simply changing film speed.
Weston cells seem to be among the most rugged. Selenium cells are damaged
by heat and by moisture. Weston had a patented method of making the cells
that resulted in better moisture sealing than others. Unfortunately, it
doesn't give it any greater resistance to heat. If the meter has ever been
over heated the cell will have lost sensitivity. The same technique of
reading the same actual light level on two ranges for checking works for
all Selenium meters, including the one in Rolleiflex's.
Since the Master II is calibrated for Weston speeds use the next _lower_
setting to the ISO speed index. i.e., for ISO-100 film set the speed to
Weston 80.
The main caution in using the Weston meter is to beware of the very wide
viewing angle. Its easy to get too much sky light when used outdoors.
For general use you might find the exposures are closer if the "C"
setting on the calculator is used instead of the pointer. My Weston tends
to underexpose by a stop. I think this is an artifact of a safety factor
Weston used in its speed ratings. According to foot candle measurements the
meter is dead on.
If you wan't a new non-battery meter I recommend the Sekonic version of
the old Norwood Director (I've forgotten its current model number). Its
very accurate, and versitile. The only shortcoming is the lack of very low
light sensitivity.
Weston meters are still made in England by Sangamo. They have a web site
but I don't have the URL handy. I think the current version is too
expensive.
----
Richard Knoppow
Los Angeles, CA, USA
[email protected]
From rollei mailing list:
Date: Mon, 27 May 2002
From: Jerry Lehrer [email protected]
Subject: Re: [Rollei] Rollei 3.5 E Xenotar & Meters
Richard
The currently available English made Westons are called Euromaster
and are about $250. Good meter but overpriced,in my opinion.
The longest lasting and toughest Weston Master is the original Master
1, made before WW 2. I have never seen a bad one, but almost every
Master II or III has been erratic or totally bad. They can be repaired
by Quality Light Metric in your city.
I have five Master 1's in my collection, all are spot-on! No, make that
four, I gave one to Jan Boettcher when he visited me in La Jolla last
month.
...
From rollei mailing list:
Date: Tue, 28 May 2002 10:58:51 +0200 (CEST)
From: [email protected]
Reply to: [email protected]
To: [email protected]
Subject: Re: [Rollei] [off-topic] Weston Meters, new ones and service
From Richard K.
> Weston meters are still made in England by...
Megatron Ltd
Unit 24F1, N17 Studios
784-788 High Road Tottenham
London N17 0DA, England
Tel: +44 (0)20 8365 9797
Fax: +44 (0)20 8808 6186
email: [email protected]
> They have a web site...
http://www.megatron.co.uk
http://www.megatron.co.uk/euromaster2/index.html
Info :
- I had a Weston V renewed and re-calibrated by Megatron. No problem.
Re-started for another 20 years.
- Megatron is one of the last manufacturers of high quality selenium
cells.
- I recently purchased a small Gossen Sixtino II (as it is called in
Europe, the commercial name is Pilot II in Northern America). And
..ahem... where did Gossen-Germany get the selenium cell ? (guess
;-);-))
I like the Sixtino-Pilot very much as the faithful companion of my
meter-less cameras. For example I do not trust any longer the built-in
selenium cell of my 1963 Bessamatic, so I keep the Sixtino-Pilot
handy. You switch to incident light raeding with a Gossen-style
roller-blind in a snap, a one-hand operation. No battery. Always ready
to go evenin cold weather. For the next 20 years to come ;-);-) like
any Rollei TLR recently serviced.
--
Emmanuel BIGLER
[email protected]
From: Lisa Horton [email protected]
Newsgroups: rec.photo.equipment.35mm
Subject: Here's your small light cheap good Incident meter! :)
Date: Tue, 02 Jul 2002
http://www.bogenphoto.com/product/templates/itemalone.php3?itemid=1861
For anyone who's been reading the threads on incident metering and
wondering if maybe you should check it out, here's something for you.
Gossen, a leader in light meters, is coming out with a new model
that's very small, very light, relatively inexpensive and will even
mount on your hot shoe. It reads both reflected and incident and if
it's like other Gossen products, will be a quality item.
Could be nice too for those who wouldn't mind something smaller than a
big Sekonic or Minolta meter in their bag for backup and/or double
checking.
Lisa
From: "tlianza" [email protected]
Newsgroups: sci.engr.color,sci.optics
Subject: Re: how to change regular camera values to lux?
Date: Sat, 27 Jul 2002
With the proper equation your camera would be quite capable of reporting an
estimate of the illuminance in the focal plane of the camera which would be
related to the luminance (NOT ILLUMINANCE) of the field of view. If you
are, infact, a student then go to the library and take out a good book that
describes radiometry and photometry. I would recommend Warren Smith, Modern
Optical Engineering. The light meter equation is NOT so easy to find so let
me repeat it here for you.
The calibration of reflected lightmeter relies upon a manufacturers
selection of calibration constant as per ISO specification is
2720-1974(R1994).
The ISO light meter equation for a reflected light meter is as follows
K1 = Ef *t*S/ A^2
Ef = illuminance in lux/m^2 at the film plane
t = exposure time in seconds
S = linear film speed ( old terminology ASA not DIN)
A = f#
The value of K1
10.6 > K1 >= 13.4
The value of K1 is a matter of choice by the manufacturer of the
camera/meter . The reason for the range is that method of determining film
speed (S) is not the same for all film types, hence, there are subjective
reason to "tune" the exposure to the anticipated use of the meter (negative
film, transparency, electronic sensor) . So the illuminance in the film
plane Ef can be determined from the following relationship:
Ef = (K1 * A^2) / ( t * S)
Having said all of this, understand that the question you asked illustrates
a lack of understanding of the process. You need very specific information
about the reflectance of the scene before you can estimate illuminance. In
the photographic world, a typical target is an 18% Gray card. This is a
DIFFUSE paper card whose reflectance is 18% . The illuminance (E scene)
striking that card (which is what I understand you to be trying to measure)
causes it to reflect light and hence become a source of luminance (B
scene). For a diffuse reflector, the following equation holds:
E = B * pi / R. where E has the units lux/m2 and B has the units
(lumen/m2-str); R is the reflectance of the gray card . If you are really
savvy, you might ask why it's not 2*pi, but that's another story.
Solving for the luminance we get
Bscene = Escene * Rscene / pi.
Assuming your lens is focused to infinity and the gray card completely fills
the field of view, there is a relationship to determine the relationship of
the illuminance in the film plane (Ef) in the meter equation to the
luminance (Bscene) of the reflected object. Now go to the library and find
that relationship out and post the result of your learning experience in
this group or send it to me. Hopefully you will find the answer quite
entertaining . Take a day or two to solve it, and if you can't write me off
list and I'll send you the answer. In the mean time, lets let some other
readers solve this riddle from this point. While we are on the topic of
photometric units, please excuse this small nit (don't pardon the pun): the
plural of LUX is LUX.
--
Tom Lianza
Technical Director
Sequel Imaging Inc.
25 Nashua Rd.
Londonderry, NH 03053
[email protected]
"tal carmon" [email protected] wrote:
>
> i would like to use a regular camera light meter as lux meter
> in order to do this, i need the lookup table which will convert camera
> values to luxes
>
> e.g.
>
> if my camera tells me that i should set parameters to:
> f# = 16
> exposure time = 1/60 sec
> Asa = 100
>
> how much luxes are in my field of view???
From: [email protected] (OVNIRUCO1)
Newsgroups: rec.photo.equipment.medium-format
Date: 01 Aug 2002
Subject: Followup: Small lightmeter
Thanks to all who responded to my post asking for recommendations on a small
lightmeter. A Gossen Digisix fits my needs perfectly. It is very small and
lightweight....mummy shaped, with maximum dimensions of 2" x 3" and about 1
inch thick. The meter runs on a small 3V lithium, and stays on constantly (It
can also be used as a timer, a clock, an alarm, and a thermometer.) In the
lightmeter mode, press a button and the EV is displayed for the ISO displayed.
Set the EV into the dial and read all the possibilities. All for about $110.
--Ruco
[Ed. note: Mr. Shell is a co-author of a book on light metering (Sekonic..)
and offers seminars and talks in this and related photo techniques etc.]
Date: Sun, 21 Jul 2002
From: Bob Shell [email protected]
Subject: My metering lecture now up on site and one space still open
Hi All,
I just put up the metering talk I presented at the NECCC annual conference
in Amherst, MA, last week. You can click through from the main page to the
What's New 7 Free page, or you can use this direct link to view it.
http://www.bobshell.com/cgi/bobstalk.pl
Just a reminder: I still have room for one more photographer for the
workshop coming up this weekend on the 27th and 28th.
Best wishes,
Bob
[Ed. note: notes on a low cost flash meter/light meter from Bill Cameta Camera 8/2002]
Quantum Calcu-Flash Digital Flash Meter Ser.#203465- Utilizes Blue Enhanced
Silicon Photodiode For Flash And Continuous Integrated Light Measurements
Of Incident And Reflected Light- Two Digit L.E.D. Readout Of Light Value In
1/3 EV Increments, (00 To 44)- Light Sensing Trigger And Manual Push Button
Trigger- Flash Measuring Range Incident Light 2.2 to 3,500,000 Lux-Sec./
Reflected Light 0.96-Measuring Range (Continuous Light At ASA 100) Ev 6 to
Ev 26 For Incident light/ Ev 9.3 To Ev 23.3 For Reflected Light- ASA Range
0.05 To 800,000- Shutter speed Range 1/2000 to 1/2 Sec.- Fstop Range f1.0
To f181- Foot Candle Range 0.4 to 800- Size: 4 x 2 3/4 x 1 1/4 Inches-
Weight: 4.5 oz.- Supplied With Batteries And Neck Strap (Mint-) $59.
[n.b. presumably long sold by the time you read this, just for spec's and info ;-)]
From medium format mailing list:
Date: Fri, 9 Aug 2002
From: [email protected]
Subject: Re: [medium-format] Light meter
Bijan, although I've never owned one myself, I've read that the older
selenium meters weren't as sensitive as the newer CDS/battery-powered ones.
They seem to be useful outdoors, but not in.
The old Gossen Luna Pro's are good meters; but took mercury batteries. Gossen
does sell an adaptor/voltage regulator for I believe $20 that allows the use
of 1.5 volt alkaline button cells in these older meters. And they're MUCH
more sensitive than selenium. Check their web site. Prices range all over the
map. The Gossen Luna Six is supposedly the same meter, but was only sold
outside the US. I've seen them for $50-$65 US on eBay.
I spent $150 US to get a Luna Pro S, which takes a 9-volt "transistor radio"
style batter. I later found a Minolta Autometer III on eBay for $70 that
takes standard 6-volt photo cells, and does flash as well as incident.
I've seen new CDS meters that ran for around $50 from Calumet, B&H, etc. The
older Weston Masters that use a selenium cell seem to go for $10-25 US, but
are impossible to fix, often inaccurate, and use a different light scale than
our modern meters. Someone else mentioned the Gossen Pilot; they also made a
Super Pilot that was CDS, but I have no experience with either.
Be careful of buying meters on eBay, unless the seller warrants the
instrument. There are a lot of people selling dead meters on that forum
because they found one in the attic and don't know what battery to put in or
how to test it. A new meter for a Gossen runs about $65 just for parts.
Good luck!
Date: Tue, 9 Jul 2002 21:54:51 +0200
From: "Simon A. Spaans"
from rollei mailing list;
Date: Thu, 22 Aug 2002
From: Richard Knoppow [email protected]
Subject: Re: [Rollei] Using EV on Rolleicord
you wrote:
>Hi Anthony!
>
> I use the Weston as a backup meter to the Pentax Digital Spot. I
>prefer the Pentax for it's quick operation as it displays in the finder
>the EV number. My favorite Rolleiflexes are the T and the earlier
>EVS models. So, with the Pentax meter, you can bypass the exposure
>meter dial altogether and transfer the number directly to the camera.
>It's the same with the Hassle or the Rollei SLRs and others as well.
>And, of course, spot meters offer the known advantages.
>
> If you can't afford one, you can replace the Weston for $20 to $30.
>It's a great meter. I'm looking for the cone diffuser for mine for incident
>readings.
>
>Cheers,
>
>Rich Lahrson
>Berkeley, California
>[email protected]
>
>Anthony Gal wrote:
A caution, check Selenium cell meters like the Weston for degradaton of
the cell. This is easily done by checing at a light level which can be read
on both the lower and upper end of the scale by changing the light
attenuator. Set it for light which reads near the top of the scale for the
low light setting. When read on the high-light setting the reading should
be the same. If it reads higher on the high-light setting it indicates the
cell is bad.
Selenium cells rarely fail completely. Rather, they become non-linear,
loosing sensitivity for the higher intensities. Since the error is not
constant with reading there is no way to compensat for it. Typically it is
a stop or more.
I think, but don't know for certain, that its caused by a change in the
internal resistance of the cell.
Ideally, a Selenium cell should be used with a meter with zero internal
resistance. Such a meter could be made electronically but practical
magnetic meters must have some internal resistance. The meter is
compromised between linearity and sensitivity. Weston, and probably other
meters, have shaped pole pieces to introduce a specific non-linear curve to
the scale to compensate for the cell/meter combination. If the cell changes
the compensation is no longer correct and the meter becomes inaccurate.
There is no fix for this but replacement of the cell. It can be done but
used Westons are cheap enough and plentiful enough to make replacement of
the whole meter more economical.
Complete failure is usualy caused by a crystalized solder connection. Not
hard to fix other than some meters are hard to get open.
----
Richard Knoppow
Los Angeles, CA, USA
[email protected]
From: "UrbanVoyeur" [email protected]
Newsgroups: rec.photo.equipment.35mm
Subject: Re: 35mm, slide film, and the zone system
Date: Mon, 16 Sep 2002
Ye, you can use the zone system with slide film.
The "expose for shadows, etc.. " is only a partial, quickie application of
the Zone system.
Two use the zone system with slides, you should apply a slightly fuller,
more rigorous zone system.
I use the Z system with all my slide shooting. Here's what I've found:
- Fuji Provia Films can represent 5-10 zones depending on exposure &
processing. 7-9 is normal.
- You have to familiarize yourself with the effects of push (n+1, etc) and
pull (n-1, etc) processing
- Each lab/film combination is different. For that reason I limit the number
of films I use regularly (2 - provia 100 & 400 F) and the number of labs (1
main, 1 backup)
Here's what works for me:
- Use a spot meter- I prefer the Zone VI modified Pentax Digital.
- Meter the areas of key detail interest and decide what zones to place them
in.
- Fresh USA film
- Pro labs.
Here's where it gets tricky:
If I shoot film and process normal, I know I have 7-9 zones to play with. I
will pick the one key high area and one key low area, and decide what zones
I want them to be in. Everything else falls where it will.
If I am shooting people on the street, I will meter the face or skin of
interest, and place it in a zone based on my perception of their skin tone -
usually Zone 4-5 for dark skin, and zone 6-7 for light skin. Everything else
falls where it will.
If I don't have time to meter, I judge relative to my skin. My palm meters
the same as a grey card. In summer (now) the back of my hand is two stops
below that, in winter it is one stop below. Everyone I see gets placed
accordingly. How high I place them depends on the level of detail I want and
how much other detail I have to hold in the scene. Your mileage may vary
:-).
If I am pushing the film to a higher speed, I know that I have only 5-7
zones, and I generally place Zone 7 and let the rest fall where it will.
Sometimes I bump 7 into 8 or beyond (blowout) to capture low end detail,
still realizing only 5-7 zones will fit on the film.
If I am shooting outdoors with oodles of light, a slow film, and a wide
range say 10-12 zones, I may pull the film, realizing that I lowering
overall contrast and expanding my range to 10 (sometimes 11) compressed
zones. I meter my lows and highs, then place my lowest area important
area - Zone 3 or 4 so that the highest area of interest falls not higher
than zone 8.
Again, this depends on knowing you films, meter and labs. It takes time,
three cards gray, white & black ( or better a color target), and some
film.
--
J
www.urbanvoyeur.com
"Eric Cohen" [email protected] wrote ...
> Greetings,
>
> I am trying to figure out how to deal with contasty scenes when
> shooting color slide film. I know if I were shooting B&W print film I
> could use the zone system -- expose for the shadows and alter
> developing time to bring out the highlights. My understanding is that
> slide film can only capture 5 stops and that what ends up on the slide
> is all I get; I don't have the option of N -1 with slide film? Or does
> the zone system work with slide film?
>
> Are there other methods for capturing a wide range of tones on slides?
> The other techniques I am familiar with are graduated-neuteral density
> filters, polarizers, and smart flashes. Anything I am missing?
>
> As an FYI, I am now trying to deal with street scenes that have lots
> of contrast. I invariably end up with sections that are either too
> dark, too light, or both. What options do I have or do I just need to
> figure out a way to use the contrast in the pic?
>
> All thoughts and comments are most welcome!
>
> Eric
From: [email protected] (Lance Morgan)
Newsgroups: rec.photo.equipment.35mm
Subject: Re: 35mm, slide film, and the zone system
Date: 16 Sep 2002
....
We must use different Provia 100 & 400s! The most I've been able to capture
is 5 to 5 1/2 zones. One might add a stop or so for subjective differences
in the interpretation of capturing detail. Higher ISO's generally
offer a bit more dynamic range (depending on stock, sometimes up to
1/2 to 1 stop more).Tony's suggestion was good - also making accurate
inference to the limited zone/stop range abilities of printing on
photo paperFilm can be pulled or pre-fogged/flashed to increase
dynamic range, but, in general, the slight gains aren't worth itEric -
you're on the right track (btw, what slide film/s are you currently
using?). You need to either add or block light to decrease contrast;
selectively compose so the scene can be captured by the film's dynamic
range, w/particular emphasis on accurately placing the tonality of the
most important highlight(s); experiment with some higher ISO slide
films; switch to color print film for ~ 7 stops of dynamic range;
switch to B&W film for ~10 stops; or don't shoot because the scene it
too contrasty
Rgds,LM
From: "UrbanVoyeur" [email protected]
Newsgroups: rec.photo.equipment.35mm
Subject: Re: 35mm, slide film, and the zone system
Date: Mon, 16 Sep 2002
I think a lot has to do with where you place your middle values and where
you get the film processed. And using a color corrected spot meter helps.
With Provia 100 & Provia 400 a 7 stop difference between detail in the highs
and details in the lows is standard for me with shot at the rated speed and
processed normal. If I place my middles carefully in relation to my high, I
can hold detail across 8 1/2 to 9 stops with Provia 100. That does not mean
however that I can get a decent scan or print with detail across the whole
range ... :-)
But if it is important to get 8 zones, I will pull the Provia 100 and shoot
it at a slower speed.
For me, the higher ISO films have a shorter range, and the higher the speed
I shoot at, the smaller the range. When I shoot Provia 400 F @ 400 and
process normal, I get a 7 stop (zone) range of detail. When I shoot it at
800 and process N+1, I get 5-6 zones. At 1600 and N+2, I get 4-5 zones,
sometimes just 3 depending on where I place the middles in relation to the
highs.
With color neg, normal for me is 8-9 zones with most Fuji film. I can expand
the range to 10-11 with pulling. B&W is typically 10-12 zones, depending on
processing and film.
I have seen others get 14 zones or more on B&W film using large and medium
format, but one was a former student/assistant/printer of Ansel Adams, and
other was a photo professor with 30 years experience. I personally have
never been able to get more than 12 zones, and that was using Efke 20 & 50
film, and a modified D-76 and printed on graded fiber with quite a bit of
work (2 bath developers, toning, cold light head, etc.)
Your mileage may vary.
--
J
www.urbanvoyeur.com
Date: Mon, 16 Sep 2002
From: "Mxsmanic" [email protected]
Newsgroups: rec.photo.equipment.35mm
Subject: Re: 35mm, slide film, and the zone system
"Eric Cohen" [email protected] a Tcrit
> My understanding is that slide film can only
> capture 5 stops and that what ends up on the slide
> is all I get; I don't have the option of N -1
> with slide film? Or does the zone system work
> with slide film?
The Zone System works best with black and white film.
However, you don't need a "system" to expose correctly. Just spot-meter
your scene, and if it spans more stops than you can put on film (five stops
or so for slides, as you observe), decide where you want details to be
retained, and expose for those. Try to make sure that the most important
details in the scene fall within the 5-stop range based on your chosen
exposure. I do this for night shots routinely, and the results are superb.
For example, shooting slides at night, I'll spot-meter the brightest parts
of the scene in which I want to hold detail, then count down 2.5 stops or so
and expose at that setting. If there are both important shadows and
highlights, and they are more than five stops apart (and at night, they are
sometimes 6-8 stops apart), I try to pick a middle ground, and accept that
I'll lose detail in both. (Some of this can be recovered with a good scan
and Photoshop, but it's easy to overdo, so you have to be careful.)
> Are there other methods for capturing a wide
> range of tones on slides?
There aren't any methods for capturing a wide range on slides. Slides
aren't intended for that. Slides reproduce density differences in
approximately real-life magnitude; which means that they cannot reproduce
more than a couple of stops realistically. This is a consequence of the
fact that they are intended for direct projection, and so they must look
good as is (there is no printing step to compensate with).
> The other techniques I am familiar with are
> graduated-neuteral density filters, polarizers,
> and smart flashes. Anything I am missing?
Multiple exposures and compositing in Photoshop. Very time-consuming, but
occasionally useful. More trouble than it is worth most of the time,
especially if you expose the original with care.
> As an FYI, I am now trying to deal with street
> scenes that have lots of contrast. I invariably
> end up with sections that are either too
> dark, too light, or both. What options do I
> have or do I just need to figure out a way to
> use the contrast in the pic?
If the contrast in the original scene exceeds five stops or so, you'll have
to resign yourself to either losing part of the shadows or blowing some of
the highlights; you can't have detail in both (on slide film). You can
meter to hold the detail in one or the other, however. If the contrast is
five stops or less (actually as much as six or seven, since you may not need
as much detail in highlights and shadows, anyway), you can carefully meter
to fit it all right over the range of the film, with good results.
If you consistently need more than five stops, shoot negative film. If you
need the largest possible range, shoot black and white, which can handle 11
stops or so if properly exposed and developed (most films).
From: "Q.G. de Bakker" [email protected]
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Should I buy this Gossen Profisix? (OT)
Date: Sat, 21 Sep 2002
[email protected] wrote:
> [...] In any case, don�t care too much about
> dust and wear - these Gossen gems seem to live forever (or nearly so). Once, a
> Gossen representative told me that this is a real problem for his company...
No they don't live forever.
I went through a brace of Lunasix F and Profisix meters. After a while (2-3
years; will perhaps depend on use) they all developed the same problem: an
erratic but very frequent short circuit in the electronics somewhere,
causing the needle to swing violently to the right. Putting pressure on the
meter's housing in some spots would induce the same symptoms, pressing it in
other places would subdue the same.
The variable resistor in the upper part has three metal filaments sticking
out below. They have to make contact with three counterparts in the lower
half: just touching, no plug, or other secure contact. Movement (like
turning the dial operating the resistor, or pressing both upper and lower
halves of the housing) could perhaps break that contact, so i made a
permanent contact by soldering some wire leads from one to the other.And lo
and behold, it seemed to do the trick. But no... after a very short while
the problem returned. Noone appeared to be able to repair them permanently,
so the only thing to do was get another meter.
I have heard about the same thing happening from other people using Lunasix
F or Profisix meters too. A pitty since they are great meters, while they
last.
I have replaced them by the second version (not marked as such; differing
from the first version in that it can display EVs, where the first version
displays something like cd/s^2) of the Gossen Mastersix. A truly perfect
meter, though a bit big compared to modern day meters.
By the way, the Profisix and Lunasix F have always cost exactly the same,
and still do. The Lunasix F offers flash metering capability which the
Profisix lacks. But the Profisix can be used with a full set (more than were
available for the Lunasix meters, now severely reduced in number) of
attachments, and is more sensitive. Difficult choice.
Date: Thu, 19 Sep 2002
From: Lassi [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Shooting with digital to preview exposure
...
> Sure, but then again, I've been taught the "extended" sunny 16 rule -
> open up some more if you don't get the light directly on (most of) the
> subject ...
"THE ULTIMATE EXPOSURE COMPUTER", http://www.fredparker.com/ultexp1.htm,
and scroll close to the bottom.
-- Lassi
From: [email protected] (RD)
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Shooting with digital to preview exposure
Date: Thu, 19 Sep 2002
"Jeff" [email protected] wrote:
>I forgot
>the meter at home, so I decided to use the sunny 16 for my shots. F11 at
>1/125 would have been ideal under open sky condition, but half of my shots
>had treed scenery with lots of shadows. Those shots are definitely
>underexposed by at least 1 stop.
But the Sunny 16 rule is only the starting point:
Close 1 Stop
Bright Sunny day, scene over snow or light sand
Sunny 16 - Reciprocal of ASA @ f/16
Bright sunny day, *hard shadows*
Open 3 stops shooting into shade
Open 1 Stop
Bright hazy sun, *weak shadows*
Open 3 more stops shooting into shade
Open 2 Stops
Cloudy but bright, *no shadows*
Open 3 more stops shooting into shade
Open 3 Stops
Heavy overcast, medium grey sky
Open 3 more stops shooting into shade
Memorize this list and you'll be able to identify most outdoor shots
from EV16 to EV9. The Ultimate Exposure Computer site that I mentioned
earlier (and someone else here has also mentioned in response to your
post) has descriptions of additional EVs, such as those you might
encounter indoors, or at night.
Incidentally, I have a 35mm with excellent multi-zone metering. It
ruined one of my favorite shots a few years ago. The smallish subject,
completely in the shade, is badly underexposed due to lighter (but
relatively unimportant) surroundings. I know now that using Sunny 16
and opening 3 stops would have taken a perfect picture.
JL
From camera fix mailing list:
Date: Tue, 22 Oct 2002
From: "Vincent" [email protected]
Subject: Re: Solder difficulty
Dear Pat, Jon, and Roland, This problem will continue to hound this
forum. The problem with trying to solder to a connector or wire that
has become corroded from battery leakage is you are no longer
soldering to the original pure metal that was there in the beginning.
The alkaline compounds that leaked from the battery and caused the
corrosion, have changed the composition of the copper in the wire, if
it went that far, and deep into the metal pores of the battery
chamber. Of course you have been able to solder it with acid core
solder, as it uses hydrochloric acid as a flux, but this might just
prove to be not only overkill, but if it gets into anything else in
the camera the eventual undoing of the repair. The reason it will not
solder in a normal manner with electronic solder, is because the
materials have become something entirely different because of the
chemical reactions to the alkaline compounds. Replacing the wire is
of course a necessary course, as the alkaline compounds will continue
migrating through chemical reaction, till the whole wire is no longer
copper, but some sort of oxide of copper. As to the battery box and
its contact, perhaps if the damage is not too severe, then a soak in
some white vinegar(a milder acid)as this could neutralize the
alkaline compounds. If this doesn't work, then replacing the battery
box seems to be a better choice. One other choice is to try using Sta-
Brite soft silver solder. The flux that comes with it is also a
milder acid compound, and would probably neutralize the alkalines in
the metal tab that you need to solder to, and the acid compound in it
could then be neutralized with another milder acid such as white
vinegar, and then finally washed with distilled water and alcohol. I
know I have told this story somewhere before, but years ago I spilled
some battery acid on a brand new down vest while working on my truck.
Everyone knows what will happen to such a garment if you put it in
water, and wash it. It will become mush. Instead I bought two gallons
of white vinegar, and soaked the vest overnight, and the next day I
washed it normally. The result was there was absolutely no damage to
the fabric of the vest, and the dye where the hydrochloric acid had
spilled onto the vest was just a little shade lighter, hardly
noticable unless you knew. I wore that vest for the next four years
with no ill effects from that accident. The lesson I learned of
course is to dilute strong acid with a weaker acid before putting
water on it to flush out the acids, as the water acts as a catalyst
to the strong acid, the very reason we add water to acid core
batteries. I hope this long post helps all of you, as this is quite a
common problem encountered by all technicians. Good Luck!!! Vincent
From camera fix mailing list:
Date: Tue, 22 Oct 2002
From: [email protected]
Subject: Re: Re: Solder difficulty
[email protected] writes:
The result was there was absolutely no damage to
the fabric of the vest, and the dye where the hydrochloric acid had
spilled onto the vest was just a little shade lighter, hardly
noticable unless you knew.
Yes, it is very true that if one is going to use acid core flux, one must
take great caution so as not to allow any of the flux to contact any metallic
components in the vacinity of the soldering operation. One must devise ways
of protecting adjacent parts.
As far as copper wire that has become completely decomposed by mercury
outgassing, of course the only alternative is to replace the wire. This
usually involves some degree of disassembly.
Automotive battery acid is usually sulfuric acid, and is probably of a much
higher Baume than the hydrochloric acid found in solder fluxes.
I do believe that, especially on some Japanese cameras, that some electical
terminals are flashed with an alloy that is rosin core solder compatible, and
if that flash is destroyed in any way, the base alloy underneath will not be
very friendly with rosin core solder. I have noticed this on some parts that
have not been exposed to the devastation of mercury battery outgassing.
I have also noticed that on the Minolta Hi Matic E and F cameras, the black
wire connected to the battery box almost always decomposes and has to be
replaced.
The problem always seems to be most severe on the black wire. I think the
decomposition might be caused by a reaction between the plastic insulation or
the black dye used in the insulation and the copper wire.
But then Minolta evidently did not use a very good grade of copper wire on
these cameras, and on several other models.
Comments?
Roland F. Harriston
From camera fix mailing list:
Date: Wed, 23 Oct 2002
From: "falllake2000" [email protected]
Subject: Re: Solder difficulty
--
Greetings,
The contact you are tring to fix is stainless steel and is very hard
to re attach the wire to,
You need to order some "conductive exopy glue' and bond this together.
Try a google search and you will be successful. A small 2 part tube
set will cost you around $25.00 including shipping.
E-mail me back if interested and I'll look up the place I get mine. I
have fixed these great old K-1000s this way and it works great.
Regards, Dave
From camera fix mailing list:
Date: Wed, 23 Oct 2002
From: "falllake2000" [email protected]
Subject: Re: Solder difficulty
Conductive epoxy additional info
I got this information from the "National Camera Inc" Technical
Training manual on K-1000, page 19. and have been very successful
using this stuff on the K-1000s in my Photography lab. (My computer
repair friends use it for repair on circuit boards.)
A good on line source is;
http://www.web-tronics.com/2400.html
regards, Dave
From camera fix mailing list:
Date: Wed, 23 Oct 2002
From: Jim Brokaw [email protected]
Subject: Re: Solder difficulty
This has been an interesting thread on soldering difficulties... I've
learned some things and I think I'm going to look for some (mild, I hope)
acid-core solder.
I encountered difficulties soldering to a selenium cell from an old light
meter. I used conductive epoxy, but it wasn't very satisfactory either, if
you pulled the wire it came right off. Then the connection wasn't very good
either, I can't tell if I scraped it clean or down to the substrate (no
current flow then).
How about any suggestions or help on soldering (or somehow connecting) to
selenium cells and solar cells in general. I took a solar cell out of a
cheap solar-powered calculator to use in place of the selenium cell, and it
appears to be glass with the flat-ribbon leads glued onto it... I need to
connect some regular wires to it instead... how?
onnect some regular wires to it instead... how?
--
Jim Brokaw
Tim Engel at [email protected] wrote:
> Pat,
>
> The contacts are usually either nickel plated or stainless steel, neither
> one of which is easy to solder. Lead/tin solder won't work. Use silver
> solder, a good silver solder flux, and higher temperature than you would
> normally use for lead/tin. Apply a heat sink clamp to the contact between
> the plastic housing and the end of the contact where you will be soldering.
> Cut off the old, contaminated end of the wire. Strip and pre-tin the
> conductor. Pre-tin the contact. Then solder the wire to the contact.
>
> Regards,
> Tim Engel
From: "Robert Chiasson" [email protected]
To: [email protected]
Subject: Re: [Russiancamera] Selium meter material???
Date: Tue, 26 Nov 2002
That would be Megatron:
http://www.megatron.co.uk/homepage.html
They sell standard sized photocells, plus will cut one to size for a fee.
Let us know how you make out, I've been thinking of getting a cell for my
Retina cut.
------
Robert
Date: Tue, 26 Nov 2002
To: Russiancamera-user [email protected]
Subject: Re: [Russiancamera] Selium meter material???
From: "Steve K." [email protected]
A place ont the 'net American Science and Surplus has solar cells for sale
too, they are not specifically toted as being selenium cells, but they might
work?
Here's the address:
http://www.sciplus.com/category.cfm?category=136
This should take you right to the solar cell page. Lots of other goodies too!
Steve K. (Iggymo)
Date: Sun, 1 Dec 2002
From: Godfrey DiGiorgi [email protected]
To: [email protected]
Subject: Re: [HUG] Motorized
Long as we're talkin' about gray cards, a good approximation of an 18%
Neutral Gray card is the clear blue sky on a cloudless day. Just point
a reflective meter up there away from the sun and take a reading.
Godfrey
> Forget the grey card. Just learn to recognize medium tone. It's really
> not that hard...
Date: Sun, 01 Dec 2002
From: Tom Christiansen [email protected]
To: [email protected]
Subject: Re: [HUG] Motorized
you wrote:
>Long as we're talkin' about gray cards, a good approximation of an 18%
>Neutral Gray card is the clear blue sky on a cloudless day. Just point a
>reflective meter up there away from the sun and take a reading.
I'd say the sky near the horizon is probably 2/3~1 stop brighter than
medium. The deep blue sky at zenith is medium. So is lush green grass.
Tom
from rangefinder mailing list:
Date: Thu, 26 Dec 2002
From: Jim Williams [email protected]
Subject: Re: [RF List] cDs vs. Silicon light meters
Douglas Anthony Cooper wrote:
> I've heard conflicting reports regarding silicon vs. cDs light meters. I've
> just taken possession of an old Pentax Honeywell one-degree spot meter,
> which has a CdS cell, and seems to meter at a very low EV. Now I'd always
> heard that the Gossen SBC (Silicon Blue Cell) was the champion at low light
> levels, but I just looked up a usenet post from a guy who *designs* light
> meters, and he insists that the cDs has a greater range, if you give it
> proper time to settle. Sometimes they can indicate 8-hour exposures;
A CdS cell works for light metering because it's a resistor, the
resistance of which varies in response to light. It has high "dark
resistance" -- bright light = low resistance; dim light = high
resistance. You can make a very simple CdS light meter (as I often did
as a kid) simply by hooking a meter movement, the cell, and a battery
together in series -- calibrate the meter's dial markings against a
known exposure meter, make a chart, and you can use it to determine
exposure values, at least over a limited range. Essentially even the
most sophisticated CdS meter is nothing more than this simple type of
circuit: all the additional components are just for calibration,
battery checking, etc.
This high-dark-resistance behavior means that up to a point, you can
make a CdS meter as sensitive as you want just by pushing more voltage
through it. If the homemade meter in the example above wouldn't measure
light as dim as I wanted, I could simply hook up more batteries until I
could get the meter needle off the peg. This would make the meter TOO
sensitive to read higher light levels -- the meter needle would bang
against the top of the scale when the higher light level made the
cell's resistance drop -- but this could be solved by switching an
extra fixed resistor into the circuit, making a 'dual-range' meter.
You couldn't actually push on this process indefinitely, though, to
increase a CdS-cell meter as far as you wanted. The reason is that the
cell's response isn't perfectly linear: A specific change in the amount
of light on the cell would produce a corresponding change in its
resistance over the "fat part" of its range, but in really dim
conditions the consistency of this relationship would drop off. That's
why there's a minimum readable light level in any type of CdS meter --
the circuit might still be responding below that level, but the
readings you'd get wouldn't be reliable.
Another big drawback to CdS metering is the cell's "memory effect" --
if the cell has just been flooded with bright light, it'll take a few
moments for it to settle down and give an accurate reading at a low
light level. This is why the instructions for dual-range CdS meters
usually suggest that in borderline light conditions, you start out
trying to get a reading on the bright-light range before switching to
the low-light range. A related problem is that a CdS cell can take
several seconds to acclimate itself to low light levels, so when taking
a reading in really dim light you'll often notice the needle will
"creep" for a few moments before it settles on a reading.
Silicon photocell meters work differently from CdS -- instead of
providing a varying resistance to current supplied by a battery, they
actually produce a tiny trickle of current from the light falling on
the cell. This current is far too weak to drive a meter readout
directly, but it can be amplified to produce a usable reading. This
approach wasn't practical for camera use until the development of
highly linear, low-noise amplifiers packaged on an IC chip; once those
became widely available, camera manufacturers could take advantage of
the silicon cell more readily. Most manufacturers seem to consider the
silicon cell's advantages of nearly instant response and freedom from
memory effect to be preferable, even though the CdS cell still has an
edge in absolute low-light sensitivity.
From rangefinder mailing list:
Date: Thu, 26 Dec 2002
From: Winfried Buechsenschuetz [email protected]
Subject: RE: cDs vs. Silicon light meters
Jim Williams wrote:
> Silicon photocell meters work differently from CdS -- instead of
> providing a varying resistance to current supplied by a battery, they
> actually produce a tiny trickle of current from the light falling on
> the cell.
That's true but most lightmeters use the change in reverse current of
silicon cells. They work similar to other diodes and have a very small
current flowing when the voltage applied is reversed. This current
increases when light hits the junction of ANY diode. Silicon cells have
a large junction area which will collect more light - and, of course, no
opaque housing/coating.
Date: Sun, 9 Feb 2003
From: Ron Seals [email protected]
To: [email protected], [email protected]
Subject: Re: [HUG] Need Hassy meter help
Tom,
Have you seen the new Gossen Digisix meter. Ideal for wearing around your
neck or clipping to your camera and only about $110 US new. I have not yet
used one but want to get one soon. My other meters are too big to keep near
constantly. The Digisix is a clock, timer, thermometer and accurate meter.
Sounds great.
Ron
[Ed. note: thanks to John for making this resource page available!]
Date: Mon, 17 Feb 2003
From: "John D. esq" [email protected]
To: [email protected]
Subject: New NEW..NEW
Robert,
This might be interesting checkit out
The story of Norwood Director
http://www.johndesq.com/director
--
Regards,
John D. esq
JOHN D. PHOTOGRAPHY
From Rangefinder mailing list:
Date: Sat, 14 Dec 2002
From: [email protected]
Subject: Re: [RF List] selenium source..
[email protected] writes:
> It is possible to cut them to size, I used a dremel with the fiber
> cutting wheel on it, and my best gas mask- just in case.. Sanding the
> cut edge made sure the cell didn't short itself..
OOPs! I just cut mine to size with a pair of aviation shears (tin snips).
The are not brittle like silicon cells. The selenium coating is deposited on
a rather soft metal subatrate that cuts quite easily with tin snips. I'm
referring to the ones I got from
Electronic Gold Mine, although it is my understanding that all Se cells are
constructed in much the same manner.
Look at this URL;
http://www.megatron.co.uk/selenium/
Roland F. Harriston
From Rangefinder mailing list:
Date: Sat, 14 Dec 2002
From: [email protected]
Subject: Re: [RF List] selenium source..
[email protected] writes:
> Selenium or silicon???
>
The good thing about selenium is that its spectral response is much like the
human eye, so it responded visible light the way we see it. A very good
characteristic for photographic light meters. Silicon has better V/I
characteristics, but its spectral response is unlike the human eye. So
silicon "blue silicon" was developed to bring silicon's response closer to
the human eye and make it suitable for photgraphic useage.
Also, selenium's photovoltaic qualities die off after a while, especially if
it is constantly exposed to light. This is why everyone is looking for new
selenium cells for their "classic" light meters. But, I have three old GE
meters that are as accurate today as they were when I purchased them back in
the 60's. They stay in their boxes most of the time, however. Silicon seems
to go on forever without much output change even when subjected to high
temperatures as is the case with silicon solar panels installed rooftops.
So that's why its so hard to find clean, fresh, active selenium devices these days.
It's just not used any more. Silicon rectifier diodes even replaced the old
selenium rectifiers in electronic equipment many, many years ago.
HTH
Roland F. Harriston
From rangefinder mailing list:
Date: Sat, 14 Dec 2002
From: clint stephenson [email protected]
Subject: RE: DR summicron
I should read the rest of the answers to this thread before posting
this- but I did find a cheap source of raw selenium photocells- the best
I can deduce (i ordered several bags of them to keep zeints alive) is
that they are from a GE factory..
2 bucks for a bag of three, they have been handled sort of without care,
so it may pay to order many-
To put things in perspective, the replacement cell for a gossen pilot 2
was 14 dollars, plus about that much again for shipping and handling.
But my sweet little pilot lives again!
oh yeah- the link--
http://sales.goldmine-elec.com/prodinfo.asp?prodid=3190
Ron Schwarz wrote:
> clint stephenson said:
> >The selenium may be dirty or tired- I think there is a calibration screw
> >somewhere in the meter
>
> Does anyone know of a domestic (US) supplier of selenium photocells? I
> used to be able to pick up "blanks" that I'd cut to size, but I haven't
> been able to find any recently. Radio Shack used to sell them, and IIRC so
> did Edmund, and that outfit that was affiliated with Natcam. (That probably
> dates me.)
>
> I've purchased Weston cells from Metrocom in the UK, but I had to order
> quite a few to make it economical, and Sekonic cells (the type for their
> Studio series) are available from the importer, but I'd like to find a US
> supplier for easy ordering of small quantities of "generic" photocell
> material that I can cut to size. I realize that silicon blanks are readily
> available, but I don't consider them to be an acceptable solution for a
> variety of reasons.
From rangefinder mailing list:
Date: Sat, 14 Dec 2002
From: clint stephenson [email protected]
Subject: selenium source..
This is just to refer readers using a new title to my post aboveunder dr
summicron about a cheap us source of selenium cells--
http://sales.goldmine-elec.com/prodinfo.asp?prodid=3190
It is possible to cut them to size, I used a dremel with the fiber
cutting wheel on it, and my best gas mask- just in case.. Sanding the
cut edge made sure the cell didn't short itself..
If these seem too crude, gossen still sells the cells, perhaps the
replacement for their cheap scout 3 would serve to fix contax/kiev for
example..
I think also that adorama makes a house brand selenium meter- maybe the
parts for that meter would serve as generic replacements too..
From rangefinder mailing list:
Date: Sat, 14 Dec 2002
From: [email protected]
Subject: Re: [RF List] Selenium Cells From Electronic Goldmine
[email protected] writes:
> http://sales.goldmine-elec.com/prodinfo.asp?prodid=3190
I have ordered several packages of these cells over the years and have found
that they are really quite old, and corroded and scratched in some cases.
Some of them exhibited virtually no output while others were good and useable.
This is just to inform everyone that this is very, very old stock and that
you never know what the condition of the cells will be. This way, you won't
be disappointed.
I buy a lot of electronic parts from Goldmine, and they are a good, reputable
source for most currently manufactured electronic items.
BTW: You might log on to (join) the Argus Collector's Group (ACG) and find a
chap named Dave of Las Vegas. He seems to have a source of selenium cells. I
have never gotten any from him, but I have read on that list that he uses
them to repair Argus light meters.
That is, before they kicked off the list!
DON'T MENTION MY NAME. If you want him to respond. He and I got into a
pissing contest a while back and we have mutually declared each other
"persona non grata".
HTW
Roland F. Harriston
from rangefinder mailing list:
Date: Sun, 15 Dec 2002
From: clint stephenson [email protected]
Subject: RE: selenium source..
There's this-
http://www.xs4all.nl/~tomtiger/zenrep/meter.html
using a modern cell that looks like what would come out of a
calculator..
from rangefinder mailing list:
Date: Sun, 15 Dec 2002
From: [email protected]
Subject: Re: [RF List] selenium source..
[email protected] writes:
> I think the current output of small silicon photodiodes or photo cells
> will be too small to drive a meter
I think this is correct. The current output from silicon junction device
equivalent in size to the CdS element in a modern camera meter may not be
enough to move the galvanometer. So. a larger junction would have to be used.
Real estate (space) in most modern cameras might preclude the use of a
silicon junction device on this basis alone. So cameras use CdS
photoresistive sensing elements in the light meter, and they require an EMF.
I think the Pentax ME uses "blue silicon" photoresistive cells. I can't think
of any other camera that uses silicon in the photoresistive mode.
Some people have replaced CdS cells with a chunk of a silicon solar cell. As
W.B states, you can get the meter to swing back and forth, but I know that
ordinary silicon responds to visible light differently vis-a-vis the human
eye and the spectral response of color films. The output of the silicon chip
can be reduced by painting over a portion of the active surface with a black
felt marker pen. The output of a silicon cell is much greater than the
selenium it would replace, area-for-area.
I have heard about some people getting an old GE DW 67 or 68 light meter with
a still-active selenium cell and cutting that cell down to fit into another
meter or camrera. It seems, for some reason, that the cells used in these old
GE meters seem to stay active longer than some other brands . My old GE DW
67, 68 and PR1 meters are still very accurate even to this day. Perhaps the
cells GE used were fabricated with less contamination than some others.
Impurities and contamination are the bugaboos of semiconductor fabrication
because they tend to degrade the performance of the device over the years.
HTH
Roland F. Harriston
from rangefinder mailing list:
Date: Sun, 15 Dec 2002
From: "Sheldon Strauss" [email protected]
Subject: Re: [RF List] selenium source..
Modern cameras use silicom blue cells low output isn't a problem because the
output drives the camera's computer and doesn't have move needle on a meter.
CDS cells were used in the sixies are varible resistors that sensitive to
light but produce no current of their own, which why cameras and meter that
use them have batteries. The first camera to use the silicon blue cells was
the Fujica ST701 after its introduction every manufacturer jumped on the
bandwagon and started using in their more expensive cameras.
from rangefinder mailing list:
Date: Mon, 16 Dec 2002
From: Winfried Buechsenschuetz [email protected]
Subject: RE: Silicon Blue Cells In Modern Cameras
[email protected] wrote:
> I think the silicon blue cells are photoresistive devices, functioning like
> the older CdS cells, but with faster response times, stability etc.
That's more or less correct. Silicon cells (whether they are blue or
not) can be operated in two modes:
- photovoltaic mode, i.e. they generate a current when exposed to light
- reverse current mode. The junction in the silicon photo cells are
similar to that of an ordinary diode. Both junctions do not work
ideally, i.e. there is some leakage current flowing 'the other way'
which does no harm in most applications (it's around 1 uA or even less).
But this reverse current will change when the junction is exposed to
light (ever wondered why early transistors had a glass case painted
black from outside?). In this mode, they behave somewhat similar to CdS
photoresistors, but they are more sensitive and much faster. I tried to
test shutter speeds with a CdS photoresistor but their rise and fall
times are absolutely too slow for this application. With a standard
phototransistor I had no problems. While CdS photoresistors have a rise
time of tens of milliseconds (or even more in case of very low light)
silicon photodiodes and transistors react in less than one millisecond.
There is also a difference in color (or spectral) sensitivity between
photodetectors. Selenium cells have a spectral response close to that of
panchromatic film. CdS cells are somewhat more sensitive to the blue
region, if I recall it correctly. Most silicon photocells have their
maximum in the red or infrared range and must be 'forced' to a rather
flat spectral response by adding blue filters which in many cases are
integrated, hence the name 'silicon blue cell'.
> I did read something a long time ago about silicon blue cells performing at
> less than optimum at extremely low temperatures, but I'm not sure that it is
> a significant degradation.
Silicon photodiodes are semiconductors, i.e. they conduct current under
certain condition. One of them is temperature. All semiconductors are
temperature sensitive (I am not talking about the operating temperature
limit), and the reverse current of silicon photodiodes is also affected
by temperature. It takes quite a few effort from designers to make
measurement circuitry working stable under various temperature
conditions. (BTW even in the battery test circuit of the Canonet
QL17-GIII there is a thermistor to compensate thermal effects of the
transistor used.)
from rangefinder mailing list:
Date: Mon, 16 Dec 2002
From: BRIAN SWEENEY [email protected]
Subject: Re: [RF List] selenium source..
I checked some data sheets and did some checking on Silicon Solar Cells
and Silicon Phot Diodes used for calibration. I found some articles on
Selenium and CDS spectral curves on Photo.net by Ed Scott at
"http://www.photo.net/photo/edscott/pss00020.htm" (Gotta learn some
HTML).
Long Story Short: Silicon Photo-Diodes are sensitive far past visible
light to about 1.1u. Selenium drops down by 4 f-stops in sensitivity by
the time it hits Near-IR at 0.7u. Work is done in Solar cells to get a
flat response, as that generates the most electricity. Silicon CCD's in
Digital cameras use Blue-Green filters or Hot-Mirror filters to cut out
IR.
Photo-Metric filters using Silicon Detectors use a Blue-Green filter,
one suitable is a Schott BG-39 filter, available from Edmunds. These
filters, and Hot-Mirror filters are not cheap. Placed in front of a
Silicon Photo-Voltaic cell, they should match up with the visible
spectrum as seen by the eye. BUT not all Silicon Based Solar cells are
created equal, and spectral response can change. A hot mirror filter
cuts off everything above 0.7u, leaving just visible.
The 1998 Perdiodic Table in our Lab lists Selenium as used for
leight-meters, solar cells, and Dandruff shampoo. It is Element 34.
Bromine, listed as used in photographic film, is element 35.
Coincidence? Yeah, Silicon was listed for Solar Cells. I should have
read that column too.
I bought a Silicon Solar Cell from Radio Shack today, So I will play
with it. We should have some Photometric filters at work; they come with
the Silicon Detectors that we use and NOBODY wants them as we work with
IR. I need to find the "island of misfit optics toys" in the lab.
I asked my boss if we had any silicon photovoltaic cells. He said "what
do you mean, all silicon detectors will work as photovoltaic cells."
Brian Sweeney
Brian Sweeney wrote:
> > > Selenium or silicon???
> > >
> > The good thing about selenium is that its spectral response is much like the
> > human eye, so it responded visible light the way we see it. A very good
> > characteristic for photographic light meters. Silicon has better V/I
> > characteristics, but its spectral response is unlike the human eye. So
> > silicon "blue silicon" was developed to bring silicon's response closer to
> > the human eye and make it suitable for photgraphic useage.
From: Leonard Evens [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Light Meter
Date: Tue, 18 Feb 2003
lvc wrote:
> I want a spot meter to use for zone system work with a Mamiya 645. The
> Pentax meters seem to be the most common in the zone system books. Is there
> any advantage of the Pentax Digital Spotmeter over the Spotmeter V other
> than size and the digital read out? Will the Minolta Spotmeter work as
> well? Which one should I purchase?
>
> Vanessa
>
>
I have the old Petax spotmeter that was the predecessor of the Spotmeter
V. It still functions more or less, but I recently replaced it with a
Pentax Digital Spotmeter for reasons too complicated to explain.
You mention the weight, and that is a non trivial concern. The digital
meter is considerably lighter and it also takes up less space, which can
make a difference if you are carrying everything on your back.
As I see it, the main advantage of the digital version is that it is
more robust and less likely to be damaged by rough treatment since there
are no moving parts. On the other hand, it only reads in thirds of a
stop, whereas the analog meter reads continuously. Also, the analog
meter has a slightly larger viewing field. It is also about $100 less
expensive.
I am very happy with my digital meter, and all told I would recommend
you get that one both because it is lighter and smaller and has no
moving parts.
There are some cheaper copies of the Petax meters, made by Soligor or
sold by Adorama under its name. Also there are several other digital
meters which you will see recommended. I looked at several of those
digital meters, but I didn't like any of them. I like the fact that the
Pentax gives you an EV readings which you put on a dial to determine
f-stop/speed combinations. It makes it easy to make Zone System
placements. Meters in which everything is displayed on a digital
readout seem to me harder to use that way.
--
Leonard Evens [email protected]
From: "Brian Ellis" [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Light Meter
Date: Tue, 18 Feb 2003
I've owned both the Minolta Spotmeter F and the Pentax digital spot meter.
IIn my opinion the Pentax is much better for zone system work. The Minolta
is a more elaborate meter, it has more features of one sort or another and
if you want and can use the various features then it's an excellent meter.
But if all you want is a meter for is zone system work then the bells and
whistles at best are unnecessary and at worst get in the way and make the
meter more complicated to use. More importantly, even the basic readouts
aren't very good for zone system work because they simply tell you the f
stop or shutter speed and you have to mentally calculate the zones from
there. The Pentax digital meter is ideal for zone system work. You buy a
little zone sticker for $5 from Calumet, put it on the meter, and then all
you have to do is take readings and look at the sticker to see on what zone
everything you read will fall.
I much prefer the Pentax digital to the analog, partly because of the
smaller size and weight but mostly because you have to take the analog away
from your eye every time you take a reading to see what the reading is,
which to me is very inconvenient when you're metering multiple areas in a
scene. With the digital, the read out is in the viewer so you can take
readings all around the scene without ever having to take the meter away
from your eye. But I've never used the analog meter, just played around with
one a couple times and that was some years back, so maybe there are some
advantages to it vs. the digital that I don't know about.
...
From: Leonard Evens [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Light Meter
Date: Tue, 18 Feb 2003
Brian Ellis wrote:
> I've owned both the Minolta Spotmeter F and the Pentax digital spot meter.
> IIn my opinion the Pentax is much better for zone system work. The Minolta
> is a more elaborate meter, it has more features of one sort or another and
> if you want and can use the various features then it's an excellent meter.
> But if all you want is a meter for is zone system work then the bells and
> whistles at best are unnecessary and at worst get in the way and make the
> meter more complicated to use. More importantly, even the basic readouts
> aren't very good for zone system work because they simply tell you the f
> stop or shutter speed and you have to mentally calculate the zones from
> there. The Pentax digital meter is ideal for zone system work. You buy a
> little zone sticker for $5 from Calumet, put it on the meter, and then all
> you have to do is take readings and look at the sticker to see on what zone
> everything you read will fall.
The Zone VI sticker that Calumet sells is worth the price. But the last
time I was at Calumet, they didn't have one in stock. I made my own and
taped it to the meter. It has the roman numerals indicating the zone,
but it doesn't have the little patches of gray. If you look in The
Negative by Ansel Adams, you will see a picture of something similar
that he did. The window on the digital meter showing the exposure
values only allows placement for zones II through VIII, but it is easy
enough to extrapolate to the remaining zones. There is a corresponding
Zone VI sticker for the analog meter, or you can make your own, and you
can match all the zones with exposure values.
>
> I much prefer the Pentax digital to the analog, partly because of the
> smaller size and weight but mostly because you have to take the analog away
> from your eye every time you take a reading to see what the reading is,
> which to me is very inconvenient when you're metering multiple areas in a
> scene.
I also prefer the digital meter for the reasons you give, but I'm not
sure I understand the bit about taking your eye away. My old Pentax
analog shows the exposure value in the viewfinder, and the Pentax V
meter I looked at recently does the same thing. As far as I can see,
the two Pentax spotmeters work essentially the same way. The only
difference is that with the digital meter you read a number plus some
number of dots (zero to two) to indicate thirds of stops, and with the
analog meter you look at a needle against a scale of exposure values and
estimate where it is in between two integer values to estimate fractions
of a stop. In principle you can get more finely tuned readings from the
analog meter. For example, with the digital meter you will never get a
reading half a stop off from an integer value. But in practice it
doesn't really make any difference. You usually scan the region you are
checking, and if an area really were one half stop off, the reading
would fluctuate between one third and two thirds stops. In any event,
reading to one third of a stop means you are always within one sixth of
a stop of the true value. Visually estimating the position of the
needle with the analog meter is likely also to yield a slight error, and
in any case, it is silly to try to take readings to such precision.
There is also a psychological difference between using the analog and
digital viewfinders. In the former you see the needle and as you look
at different parts of the scene you can estimate visually the distance
in exposure values (stops) between them. With the digital meter you see
one number and some number of dots and as you look at different parts of
the scene you have to remember the numbers and subtract. Many people
have difficulty with fractions. But if you are using the zone system,
you need to translate the values to the dial anyway, and after you do
that you see everything visually in front of you. So it doesn't really
make much difference.
> With the digital, the read out is in the viewer so you can take
> readings all around the scene without ever having to take the meter away
> from your eye. But I've never used the analog meter, just played around with
> one a couple times and that was some years back, so maybe there are some
> advantages to it vs. the digital that I don't know about.
>
> [email protected] wrote
--
Leonard Evens [email protected]
Date: Tue, 18 Feb 2003
From: Tony Terlecki [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Light Meter
...
made my own stickers and printed them on inkjet labels. Worked a
treat. If anyone owns a Pentax Digital Spotmeter and wants to download
my images and print them off for their own personal use then here they are:
http://homepages.nildram.co.uk/~tigger/photography/pentax.stickers.html
--
Tony Terlecki
[email protected]
From: [email protected] (SAcapts2001)
Newsgroups: rec.photo.equipment.medium-format
Date: 19 Feb 2003
Subject: Re: Flash meter true needs
>1- 1 degree to 4 degree zoom spot meter (OK, the zoom feature isn't worth a
>lot of extra money but I have used it to good advantage a few times)
>2- Incident light meter (non-flash meter mode)
>3- Flash meter
> a- Can trigger flash via PC connection on meter
> b- Can meter flash triggered via another means (camera etc.)
>4- F-stop, Time (shutter speed) and EV modes
>5- Memory to save several readings (with all visible on the scale)
>6- Average several readings
>7- Uses normal 'AA' batteries available anywhere!! (This is _really_ a big
>deal when you are miles from the nearest camera store.)
>
>Probably more stuff I have forgotten/never used.
Thanks Sherman...this is exactly the info I needed to hear from a user. 2-6 of
your list are available on the 358. It does not have spot or "AA" batteries,
but does allow for a radio triggering module, as in the 608.
Found this comparrison chart on the Sekonic site:
http://www.sekonic.com/Products/608_358.htm
It helped to put two side by side. I have spot metering in my Mamiya which has
worked quite well...but then again I've never had a separate meter available
which would allow me to leave my camera stationary to get the readings. Just
not sure it would be worth the extra $400. I want to get what I need and WILL
need, but can't afford to blow the money without reason.
From: Leonard Evens [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Pentax spotmeter; calibration?
Date: Wed, 19 Feb 2003
[email protected] wrote:
> I've got an old Pentax spotmeter. One of the two batteries
> in it died (anybody know a source for 640A alkalines?). As
> I was trying to open the case to see what batteries were
> needed, I very stupidly turned what appears to be a
> calibration screw. :-(
>
> I'd appreciate pointers or references on re-calibrating this
> meter; the general procedure ought to be easy enough but I
> only see one calibration screw--does that affect both of the
> ranges on this meter? Are there any tricks, tips, or secrets
> about this I should know? TIA.
Can you describe the meter in more detail?
I think you may have one of the original Pentax meters like mine. If
so, one of the batteries was supposed to be a mercury battery, and it is
a real hassle figuring out what to do for replacements. The other is
just a standard 9 v alkaline battery. What I did was get a Wein 1.35 v
battery (MRB625). (You can find such batteries in large photosupply
stores like Helix, Calumet, B&H, etc.) This is roughly the right
voltage, but it is not large enough to fill the battery compartment. I
rigged up a holder with a coil of copper wire to fill up the space, and
it works in a fashion. But the batteries get used up pretty quickly,
and there is no good warning that the battery is no longer working. The
readings are just off. I looked around for a non mercury replacement
that was the right voltage and fit properly in the compartment, but I
couldn't find one. You can find alkaline batteries which are the right
size, but the voltages are way off. If you use the Wein battery you
should check the meter against a good standard for different EV
readings. You will probably find you need some corrections , perhaps up
to half a stop, for some parts of the range.
I suspect the screw you turned was the screw for zeroing the ammeter.
If so, what you do is remove the 9V battery, look through the meter and
turn the screw until the meter needle points at the zero point, which
should be a big dot on the left. Except for that there shouldn't be any
other calibration.
You are supposed to check the status of the 9V battery by pressing the
battery check buttom. To check the status of the other battery, you are
supposed to focus on a spot which readers 10 with the low light setting
and see if it also reads 10 on the high light setting. But if you use a
replacement battery, as I said, that may no longer work. That is, it
will satisfy the test, but the readings for high values will be way off.
I finally got tired of fiddling with mine and got myself a Pentax
digital spotmeter.
--
Leonard Evens [email protected]
From camera fix mailing list:
Date: Tue, 22 Apr 2003
From: Jon Goodman [email protected]
Subject: Re: Selenium meter cells
It is my understanding humidity and breaks, cracks or
flaws in the cell's glazing is the main culprit.
Exposure to light causes breakdown, but I believe it
would happen more slowly. I think it is principally a
matter of how well the cell was sealed when it was
made. I have some over 50 years old that still work
accurately (I've found Gossen to be among the most
long-lasting), and I have some made about 15 years ago
that barely work at all. I'd say use the camera and
enjoy it while it is working. I wouldn't store it in
direct sunlight, but I wouldn't do this with any
camera for a lot of reasons.
Jon
From camera fix mailing list:
Date: Tue, 29 Apr 2003
From: Manfred Mornhinweg [email protected]
Subject: CdS cells
Hi all!
Replacing CdS cells with generic spares is possible, but will usually
require some selection. The basic curve is a characteristic of CdS, and
will be pretty close for any cell, but the absolute resistance for a
given light level is VERY different for individual cells. Even cells
from the same batch have great variations. So it may be best to buy a
variety of them, a fair number of each kind, and then select the best
cell, or the best series/parallel combination of several cells, to
replace the original one.
I just checked at RS-components. They have two sizes of CDs cells
available.
The smaller one measures 4.2 by 3.6mm, and is rated for 5 kiloohm
typical at 100 lux, 20 to 100 kiloohm at 10 lux, and 20 megaohm
(essentially open circuit) in darkness. It costs 1 Euro in single
quantity.
The other cell is about twice as large. The ratings are 400 Ohm at 1000
lux (note the other was rated at 100 lux), 9 kiloohm typical at 10 lux,
and about 1 megaohm in darkness.
It can be quite a test of patience to come up with a fitting cell for a
given meter, or with a combination of cells that provides the correct
resistance. But it CAN be done.
Any resistors added to the circuit will cause a deviation from the clean
CdS curve, and thus will cause meter nonlinearity. So this should be
avoided.
I remember when I was a 12-year old newcomer to photography, proud owner
of a box camera with plastic lens, and built my own lightmeter based on
a large CdS cell and a VU-meter, powered by an AA carbon-zinc battery.
Alkalines were not yet around. Booh, I'm old! :-) The meter was VERY
sensitive, so that I had to cover the cell with one or more layers of
gray insulating tape to arrive at a usable sensitivity. I added or
removed layers to set the range.
Cheers,
Manfred.
Visit my hobby homepage!
http://www.qsl.net/xq2fod
From: Leonard Evens [email protected]
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Honeywell Pentax analog 1/21 spotmeter schematic & battery types?
Date: Tue, 29 Apr 2003
MVD@MVD wrote:
> Looking for schematic and battery types (a manual wouldn't hurt either)for
> Honeywell Pentax 1/21 degree analog spotmeter.
>
> Thanks
>
> Murray
I have a Honeywell Pentax 1/21 spotmeter. I can send you a copy of the
manual, such as it is, if you want, but I can tell you it doesn't have
much information in it. I've never seen a schematic anywhere.
The unit used a mercury battery for the high range and such batteries
aren't made anymore. In fact, I think it is impossible to find a
battery which matches the voltage exactly, but a 1.35 volt Silver Oxide
battery will come close. You can buy such batteries made by Wein at
good photo supply stores. Unfortunately, the Wein battery is not large
enough to fill the space. I solved that problem by using a coil of
copper wire to provide continuity. I also constructed a plastic holder
to hold the battery in place with the coil. The major problem using it
with this battery is that the readings aren't quite right, particularly
in the middle of the high range. Another problem is that when the
battery runs out, there is no particular warning; it just stops giving
accurate readings. The unit uses an ordinary 9 volt battery for the
low range, and the battery check tells you whether that battery is okay.
To test the high range battery you are supposed to center it on
something which reads 10 in the low setting and see if it reads 10 in
the high setting. Unfortunately, it doesn't obviously fail this test
when the battery is low.
I can give you additional information if you need it.
I finally gave up trying to fiddle with the meter and bought myself a
Pentax Digital Spotmeter.
--
Leonard Evens [email protected]
From: Joseph Codispoti [[email protected]]
Sent: Thu 5/8/2003
To: [email protected]
Subject: Re: [HUG] Spot Metering
Howard Blumenthal wrote:
>Roughly 2/3 of my images are currently exposed properly; the remaining 1/3
>are typically one (mostly) or two (sometimes) stops off, probably because
>of the meter.
Howard,
Taking a meter reading is only half of the battle. Especially for spot
metering, the reading has to interpreted or tailored to the scene.
Especially where in the scene a spot meter is pointed is the most important
factor.
Take a look at my primer on meter reading at:
http://www.clearsightusa.com/technotes.html
Joe
From: Colyn [email protected]
Newsgroups: rec.photo.equipment.large-format;,rec.photo.equipment.medium-format
Subject: Re: Weston Ranger 9 Light Meter
Date: Tue, 20 May 2003
Marv Soloff [email protected] wrote:
>Have acquired a mint condition Weston Ranger 9 meter. This is the
>Weston with the CDS cell and a battery. Problem is, the battery, a
>mercury V14 (2.7 volts) is history. The Wein cell is expensive and
>clumsy, using two LR44's is not an option without rewiring the meter.
>Question: has anyone converted the circuit to take two MS75s or LR44s
>and how did you do it?
>
>Regards,
The best way to convert this meter is to get 2 schottky diodes p/n
NTE582. Open the meter to gain access to the battery wire and unsolder
it from the battery housing.
Determine where to place the diodes and solder one end to the battery
terminal noting the placement of the band on the diode. Solder the
next diode in series with the first one and solder the wire to the
other end.
Re-assemble and test. If you get no meter action unsolder from the
battery terminal and wire and reverse installation.
For a better explaination check out my page at
http://www.colyngoodson.com/minolta.htm
From: [email protected] (Dld2419)
Newsgroups: rec.photo.equipment.35mm
Date: 14 Jun 2003
Subject: Re: Gossen Luna Pro Light Meter
Try this site:
http://members.fortunecity.com/canoneos/manuals/gossenlunaprof.html
From: "R.W. Behan" [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Gossen Luna Pro Light MEter
Date: Sat, 14 Jun 2003
Yes, I can, Don. The screw adjusts the meter needle to the "zero" position.
To test for correct "zero" setting, remove the batteries from the meter.
Then press the range selector toggle. The needle should move to a black
line all the way to the left of the numbered scale divisions. If it doesn't
settle there, use that screw on the back of the meter to adjust it. But as
you move the screw, hold down the range selector toggle. (I get this
information not from my geriatric memory, but from the old yellowed owner's
manual I have somehow managed to keep.) Hope this helps.
Cheers,
Dick Behan
"Don" [email protected] wrote
> Can anyone tell me what the adjustment screw is for on the back of a Gossen
> Luna Pro meter? How is this to be set. I do not have \a manual for this
> meter so your help is appreciated.
> Thanks
> Don
From: "dr bob" [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: testing ;-) Re: Are used MF...
Date: Sun, 15 Jun 2003
"Bob Monaghan" [email protected] wrote
>
> I'm not sure you have to have an "in-camera" spotmeter, I find both my
> digital and analog spotmeters quite adequate despite not being "in-camera";-)
> And many handheld meters with ambient/reflected/flash metering
> capabilities also have spotmeter attachments, for those who need or want
> them.
>
> my suspicion is that we would agree on the underlying premise, that with
> both a spotmeter and a handheld ambient light meter, you need to know how
> to use them and when to apply them. There are lots of cases where each
> would be the tool of choice, but not the other ;-) Both the spotmeter and
> the ambient light meter require the photographer to point and apply them
> properly...
>
> my comment on the complex matrix metering modes related to them being
> better "guesses" by the software lookup table based on a software
> engineer's best guess of what the subject really is and what is important
> in it, to select the "best guess" exposure settings. The reason so many of
> us use spotmeters and handheld meters is there are many times when those
> "best guesses" may not be as good as we'd like ;-)
>
> grins bobm
> --
In every class I give in "general photography", that is: how to
get out from under the restrictions of the point-and-shoot, all automatic,
digital syndrome, I am still amazed at the general ignorance of the effects
of light and subject - even in the case of serious film and digital
students. About 90% of the class are surprised to learn that their light
meters, whether on camera; TTL or hand-held; color or b&w; film or digital;
operate on the basis of yielding a middle gray (18% reflectance). Most of
these students, after comprehending the effects of light meter usage go on
to much improved results.
In my personal work, I use a hand-held spot meter extensively
because it allows better control of the negative and subsequently in
producing the final print. However I rely heavily on my combination
reflection / incident meter in many cases. I find the built-in meters
useful only when on a tour bus or other P&S activities. At ant rate, I
would never use in-camera metering as a fundamental specification in
selecting camera gear except in photojournalism and candid work, of which I
have little need.
Photography should be enjoyable. For some, automatic operation
gets them out of the "drudgery" of thinking. For others that is the better
part of photography. The same thoughts go for conventional versus digital
photography - I love the smell of fixer in the morning. It smells like ...
creativity.
Truly, dr bob.
From: [email protected] (Steve Gombosi)
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Slowest ASA film ever?
Date: 3 Jul 2003
Roman J. Rohleder [email protected] wrote:
>BTW2, if anyone has a formula to calculate the EV-spektrum from the
>candela-notation... ;-)
By definition (ANSI PH 3.49-1971 (R 1976) "American National
Standard for General Purpose Photographic Exposure Meters (Photoelectric
Type"):
EV = log2 (B*S/K),
where B = field luminance in candelas/sq. meter
S = ISO/ANSI film speed
K = 12.5 (K is a conversion constant which varies according to
the units used for B).
Steve
From: Roman J. Rohleder [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Slowest ASA film ever?
Date: Thu, 03 Jul 2003
Karen Nakamura [email protected] schrieb:
>Was there really an ASA 0.8 film *ever*? Or was this for wet plate
>emulsions?
It�s not just for film. I recently received a soviet Lightmeter, type
Rapri 3201 (Radiopribor), made in Mai 1990, sold in the hot Moscow
summer of August 1990.
The dial goes down to 1,6 ISO/ASA/GOST, it responds to lighting
situations between 0,5 and 5000 candela/m2.
The reason? It was intended to be used in the darkroom as well as a
classic photographic spotmeter. The manual gives instructions to
measure contrast, gradation, exposure time with any enlarger.
For the film. I recently read Willi Beutlers "Meine
Dunkelkammer-Praxis" ("My darkroom practice" - Beutler is the man
behind Tetenal Neofin and "Beutler Developer") - he wrote that he used
films like "Fliegerfilm" and "Perutz Spezial" in the prewar times.
They were rated at 15-17� Scheiner, about 7�DIN, 4-5 ISO/ASA.
BTW, if anyone has ever stumbled across such a lightmeter, please mail
me.
BTW2, if anyone has a formula to calculate the EV-spektrum from the
candela-notation... ;-)
>Karen
>
>p.s. I'm using the term "ASA" in lieu of ISO for historical correctness.
Gruss, Roman
From: "Wes J" [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Minolta Flash Meter IV Problem
Date: Thu, 18 Sep 2003
YES!! It works after doing what you said! Hurray, and thanks.
"John Stafford" [email protected] wrote
> Wes J wrote:
> > I have a Minolta Flash Meter IV which doesn't seem to do incident metering
> > accurately. When I use the spherical diffuser for incident readings, I get
> > at least three or four stops brighter reading than when using the 5 degree
> > spot attachment for a reflected light reading off a gray card.
>
> It's a known problem. Take off the attachment (5 degree or incident) and
> push the pin in and let it out smartly a few times. If that doesn't
> work, sell it on Ebay - or is that where you got it?
From manual minolta mailing list
Date: Thu, 6 Nov 2003
From: [email protected]
Subject: Re: CdS cells for an SRT
[email protected] writes:
My question is, does anyone know if CdS cells with a
characteristic similar to the ones in the SRT are still produced, and
if so where I can obtain them?
Check out Radio Shack #276-1657.
From: John D. esq [[email protected]]
Sent: Sun 10/19/2003
To: Monaghan, Robert
Subject: New cells for Norwood Brockway
Robert,
i want you to visit :
http://www.johndesq.com/director
And see if we are really the number 1 resource on the Norwoods etc.
We can supply new cells also
--
Regards,
John D. esq
Our Portal: http://www.johndesq.com
From: John Halliwell [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Educating Stacey
Date: Fri, 24 Oct 2003
Stacey [email protected] writes
>Yep, didn't realize the newer 6x4.5's have a spot meter. It still takes some
>user skill to make them work but the tools are there. I'm sure in full auto
>exposure mode they would be a disaster as well?
Depends on the metering built into the camera. The first test I read
between the Pentax 645n (not nii), Contax 645 & Mamiya 645AF (not AFD)
showed a massive difference between 'auto' exposure. Only the Pentax had
full 'matrix' (evaluative) metering, and was considered vastly superior
to the 'full auto' modes on the others (Mamiya had their average, spot
or spot/average metering, Contax just spot or centre-weighted IIRC).
Making the Pentax superb for grab shots, when you just don't have time
to mess about. Not surprising since Pentax 35mm kit had been developing
and using it for over a decade. From memory it uses two separate 6
segment meter patterns, one over the whole frame, the other over just
the central portion.
I mainly use a handheld, and where I have in-camera metering check the
two to make sure both seem sensible for the meter technique used. But
matrix can be extremely useful when things are moving quickly.
--
John
From: "Mark A" [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Pentax Spotmeter/Zone System
Date: Tue, 20 Jan 2004
"Lunaray" [email protected] wrote ...
> I have a good understanding of "The Zone System" though I've never really
> put it to use. I want to change that though and that's why I'm looking at spot
> meters!
>
> I'll probably get either the Pentax digital meter, or their analog model.
> There are several listed on eBay and a couple of them were described as
> having a "Zone VI" modification; what exactly does this mean? How does this
> differ from just buying the stick-on "Zone Dials"?
>
> I couldn't find any mention of a modification on Pentax's web site, nor do
> any of the on-line
> camera stores mention it; is this some kind of a 3rd party modification and
> is it worth the few extra dollars?
>
> Thanks all, for my continuing education!
> --
> Ray
Calumet Photo (who purchased Zone VI Studios, the originator of the modified
Pentax and Soligors) recently stopped selling the modified Pentax spot
meters (they still sell the stock ones). They are NOT modified by Pentax.
The person who supposedly did the mods for Calumet is Richard Ritter, a
former Zone VI employee. http://www.lg4mat.net/index.html He may be able to
do a mod if you really want one.
The mods included using a better sensor and improved the baffles to
eliminate flare. But over the years, Pentax has improved their meters, and
according to some who have compared a modified meter with a stock meter,
there is no real difference anymore.
Calumet still sells some Zone Dials for $3.00 for some models. The Zone Dial
does not mean it is modified, it just makes it easy to see the difference
between Zone V (where most meters are calibrated) and the other zones
without doing any math in your head. Some people make their own dials. Go to
the Calumet photo web site and you can see the dials.
From: "David J. Littleboy" [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Spotmeters (beginner questions)
Date: Mon, 19 Jan 2004
"Lunaray" [email protected] wrote:
> First of all, I know very little about "spot-meters"! Having said that, the
> ones that I've seen that intrigue me, are the ones with a viewfinder; tell
> me, do the good ones allow you to adjust the size of the spot you're
> measuring, and how does the film-format and focal length of the lens you're
> using come into play?
There are ones that allow you to adjust, but I can't imagine that being
useful. (Mine's a 1-degree fixed angle.) The object of the game is to get as
accurate a reading as possible, and that's pretty much inversely
proportional to the angle.
With respect to focal length, I find that 1 degree is a very small spot for
even my longest lens (150mm in 645).
> Am I making it too complicated? Are they a valuable
> tool? Any thoughts, recommendations?
If you know how to use a spotmeter, it's a very valuable tool. And the basic
concept is quite simple. If you really know nothing about spotmetering, the
books advertised at:
http://www.spotmetering.com/
provide a painfully repetitious, bang it into your head at any cost,
introduction. After that, it's zone system time. If you have a digital P&S
with a spot meter, you can try out the stuff in those books immediately.
Lots of fun. If you are as much a beginner to spot metering as I was 3 years
ago, I highly reccomend doing just that. It got me started.
I bought the Pentax digital spotmeter, and it's a real pleasure to use.
However, it's only a spotmeter, it doesn't do anything other than give you a
reading on how bright the spot you are pointing it at is. The other
spotmeters do a lot more.
David J. Littleboy
Tokyo, Japan
>Can anyone here suggest some system for transferring exposure times
>from a modern meter to a Rolleiflex with non-linear times?
1 second = 1 second
1/2 second = 1/2 second
1/5 second = 1/4 second (20% difference)
1/10 second = 1/8 second (20% difference)
1/25 second = 1/30 second (16 2/3% difference)
1/50 second = 1/60 second (16 2/3% difference)
1/100 second = 1/125 second (20% difference)
1/125 second = 1/125 second
1/250 second = 1/250 second
1/500 second = 1/500 second
Date: Wed, 05 Apr 2000
From: Richard Knoppow [email protected]
Subject: Re: [Rollei] OT Screws
>Paul,
> I ripped my II apart, only to find that all the
>screws in mine are single-slotted. Interesting how the
>technology of that day was configured. I was kinda
>surprised when I stuck a screwdriver inside next to
>the meter pivot area and felt the tug from a magnet.
>That was when I discovered that there was a magnet all
>around the pivot point of the read-out needle. I
>suppose this was to provide "drag" or "damping" for
>the needle. At any rate, it was educational even if I
>couldn't figure out everything about it. When I get
>time, I'll do a total strip-down and see what size the
>meter cell is. Then, if it is worth it, I'll see about
>replacing it.
>
>Jon
>from Deepinaharta, Georgia
Richard Knoppow
Los Angeles,Ca.
[email protected]
Date: Fri, 11 Jun 1999
From: Dante Stella [email protected]
Subject: Luna-Pro Advisory
Dante Stella
From: "jupton" [email protected]
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Fixing Weston meters
Date: Fri, 14 Apr 2000
From: Paul White [email protected]
To: [email protected]
Subject: Quality Light Metric
Paul White, Photographer
Pensacola, FL
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Weston meters
Date: Mon, 08 May 2000
> Hi folks,
> Two questions to any of you out there:
>
> 1) Is there any sort of web page describing the myriad of Weston models
> out there? Looking at Ebay gives me a headache.
Newsgroups:
rec.photo.equipment.medium-format,rec.photo.equipment.large-format,rec.photo.equ
ipment.35mm
Subject: Re: Weston meters
Date: Tue, 02 May 2000
> I know the venerable Weston Ranger 9 is a 9 degree semi-spot meter,
> and when they come up for sale, they seem to be < $100.
> 1) Is there any sort of web page describing the myriad of Weston models
> out there? Looking at Ebay gives me a headache.
> 2) Anyone want to recommend an inexpensive (<$100) semi-spot meter,
> either new or used? From my reading, this is probably a moot question,
> but I thought I'd ask anyhow.
> 3) Weston Ranger 9's don't seem to come up much for sale. Is this
> because they are particularly valuable/useful to the cheapo Zone person?
Date: Tue, 20 Jun 2000
From: Richard Knoppow [email protected]
Subject: Re: [Rollei] Light Meters...
>In a message dated 00-06-19 10:42:55 EDT, you write:
> --- Bob Shell [email protected] wrote:
> > No, Sekonic bought the design, not the company.
> > They still
> > make the meter which has undergone only small
> > refinements
> > over the years.
>
> Please, please tell me where Norwood is currently
> located. I would really like to get hold of another
> Director or whatever derivative they make these days.
>
> Jon
> from Deepinaharta, Georgia
>
>Can you get replacement selenium cells and domes from Sekonic?
Richard Knoppow
Los Angeles,Ca.
[email protected]
Date: Sun, 18 Jun 2000
From: [email protected]
Subject: Re: WLF vs PME45 (formerly PME45)
Date: Tue, 27 Jun 2000
From: [email protected]
Subject: Re: [Rollei] Rollei Meters
Andrei D. Calciu (VA-4270)
Newsgroups: rec.photo.equipment.medium-format
Date: Sun, 09 Jul 2000
Subject: Sekonic L508 II Review and Incident Metering Tutorial
From: [email protected] (David Grabowski)
Newsgroups: rec.photo.equipment.medium-format
Date: Thu, 22 Jun 2000
Subject: Re: Minolta Auto Meter IIIF
>Picked up a used Minolta Auto Meter IIIF for a psalm. Both the meters on
>my YashicaMat 124G and my Nikon F90x seem to be very accurate but for
>those rare difficult situations I wanted a hand held unit as an
>alternative to my gray card. So far the IIIF seems dead on. Anyone
>familiar with this model. What's your opinion.
Date: Sat, 16 Sep 2000
From: Jim Brick [email protected]
Subject: [Leica] Re: .....meter....
>Gossen Luna-Pro Digital. Extremely thin, so you can even put it in a
>shirt pocket. Easy to read, incident and reflected.
>
>Jesse
Date: Thu, 26 Oct 2000
From: Richard Knoppow [email protected]
Subject: Re: [Rollei] 2.8D w/ meter?
>I have a 2.8D, it has a meter and a diffusing screen that fits in the case.
>Have had it just over a month, took it on a cruise where I used my Luna Pro.
>Now that I understand how the meter works, I'll test it for accuracy.
>
>Gary
Richard Knoppow
Los Angeles,Ca.
[email protected]
Date: Sat, 28 Oct 2000
From: Simon Freidin [email protected]
To: [email protected]
Subject: Re: Weston Light Meters - History, Current Sources, Repairs
Simon
Date: Mon, 27 Nov 2000
From: Gene Johnson [email protected]
Subject: Re: [Rollei] Zone system, cheap light meter.
Date: Wed, 29 Nov 2000
From: Richard Urmonas [email protected]
Subject: Re: [Rollei] TLR meter update
A and B are constants (B about 0.7 to 0.9 for typical CdS
materials)
L is the illumination
[email protected]
From: Anders Svensson [email protected]
Newsgroups: rec.photo.equipment.35mm
Subject: Re: the ol' 1/2 a ping pong ball on the UV filter trick...
> I came across an article in an Australian mag called the 'Photographic
> Trader'. Basically it involved making a cheap incident
> light meter by glueing 1/2 a white ping pong ball on to a UV filter and
> screwing the filter onto a camera lens. The area
> surrounding the ball and the filter is painted black.
>
> In the end its probably bit of a hassle to muck about taking off lenses fiddling about with filters, but it might be a fun way
> to play with exposure, assuming you have the bits handy :-)
Anders Svensson
mail: [email protected]
From: "jw&a" [email protected]
Newsgroups: rec.photo.equipment.35mm
Subject: Re: the ol' 1/2 a ping pong ball on the UV filter trick...
south carolina
To: [email protected]
Newsgroups: rec.photo.equipment.35mm
Subject: Re: the ol' 1/2 a ping pong ball on the UV filter trick...
* Robert Monaghan
From Rollei Mailing LIst:
Date: Wed, 28 Feb 2001
From: IMRE KARAFIATH [email protected]
Subject: [Rollei] Re: [OT: Super Ikonta B issues]
>> 12 exposures instead of 11
>Er, yeah. I never understood that one...but I am sure it can easily be
>'upgraded' to make for 12 exposures...
Date: Wed, 28 Feb 2001
From: [email protected]
Subject: Re: [Rollei] Wanted: Light meter
>From Finn :
> ..... I am having a hard time finding a light meter.... None of the
> camera stores around here has one.
Emmanuel BIGLER
[email protected]
Date: Wed, 28 Feb 2001
From: Edward Meyers [email protected]
Subject: Re: [Rollei] OT: Bronica 645 vs. Super Ikonta
> Wow! I looked again and guess what? The METER WORKS! Pressing the front of
> the cell seems to have done the trick! Thanks, Arthur
Date: Wed, 28 Feb 2001
From: Edward Meyers [email protected]
Subject: Re: [Rollei] OT: Bronica 645 vs. Super Ikonta
> There's only one "state of the art" exposure meter-- your brain. Arthur
Date: Thu, 15 Mar 2001
From: Bob Shell [email protected]
Subject: Re: [CONTAX] Lens Cover/Incident Meter
> From: "Stephen Woolfenden" [email protected]
> Organization: Circulation & Management Services
> Date: Thu, 15 Mar 2001
> Subject: Re: [CONTAX] Lens Cover/Incident Meter
>
> I've recently heard of a translucent lens cover that "converts" a camera
> meter into an incident light meter. Does anybody know about this?
>
> I seem to recall years ago reading something of a gadget that did this - but
> as Roger says , a tupperware top , or something similar , would do the job .
> Suggest you run some tests first though!
> Steve
Date: Fri, 04 May 2001
From: Jim Brick [email protected]
Subject: [Leica] Re: Black Cat or black anything
Date: Wed, 11 Apr 2001
From: Jim Brick [email protected]
Subject: Re: exposure meter
>I recently bought a Hasselblad outfit (503CW 50,80,120)with PME51 prism.
I shoot mostly nature and landscape and have used 35mm for years. I spot
meter almost everything. Am I better off selling the PME51 and buying a
PME45, or should I keep the PME51 and buy a handheld spot meter? Money,
while always a concern, will take a back seat to ease of use and accuracy
here. I would appreciate your thoughts.
>Ed Post
>[email protected]
Date: Thu, 21 Jun 2001
From: [email protected]
Subject: Re: Gossen meter
> I would like to seek advice for ... Regards Ow..
>
> the difference of the ProfiSix-SBC and the Lunasix-F in terms of
> reliability and ease of use.
> So far, I am only aware that Profi-Six is a more comprehensive
> system with spot metering and flash add-ons and besides that it is
> using the silicon blue cell (sbc) as compare to cds of the Lunasix.
Emmanuel BIGLER
[email protected]
Date: Thu, 21 Jun 2001
From: "Q.G. de Bakker" [email protected]
Subject: Re: Gossen meter
> I would like to seek advice for the difference of the ProfiSix-SBC and
> the Lunsix-F in terms of reliability and ease of use.
>
> So far, I am only aware that Profi-Six is a more comprehension system
> with spot metering and flash add-ons and besides that it is using the
> silicon blue cell (sbc) as compare to cds of the Lunasix.
Date: Thu, 12 Jul 2001
From: Mark Overton [email protected]
Subject: Re: [RF List] Incident metering
> A reflected light meter (such as the type you have inside your SLR, or
> in some cases rangefinder cameras) gives you a reading of the light
> being reflected from the subject. An incident light meter gives you the
> equivalent of what a reflected light meter would register if the subject
> were a 28% gray card.
> The latter was determined by movie studios (which more or less invented
> the incident light meter) to be an ideal reading for a caucasian flesh
> tone, such as that of the face of a movie actor or actress, so that
> exposures could be kept constant from one shot to the next. This later
> became the standard for photo studio photographers.
* 15 - Direct sun (clear shadows)
14 - Hazy sun (soft shadows)
13 - Cloudy bright (no shadows)
* 12 - Open shade, heavy overcast
11 - Shade of overhang, inside car (light upholstery)
9 - Floodlit night arena sports, colored-light stage, bright grocery store
8 - Inside bright store, well-lit ice rink
* 7 - Offices & stores
Date: Thu, 19 Jul 2001
From: Mark Rabiner [email protected]
Subject: Re: light meter
> I recently had my light meter stolen. I have used a Gossen Luna Pro SBC for
> years. Now I need to replace it and am not sure what to buy. I do not need
> a lot of whistles and bells, just a dependable easy to use hand held meter.
>
> What should I buy?
>
> Thanks
>
> Bill Grimwood
From: [email protected] (dan)
Newsgroups: rec.photo.equipment.35mm
Subject: FYI: Exposure Value System Charts
Chart 2: EV at Shutter Speeds & Aperture
dan
To: [email protected]>
From: "Mitch Winkle" [email protected]>
Date: Thu, 3 Jan 2002
Subject: Re: [medium-format] Re: oops...Weston Light meter
Interesting...there is also a little remembered technique by which the
older meters, like the Master II, can be used to set the
aperature/shutter speed combination withough consulting the tiny numbers
on the dial.
The older meters use a scale which reads in cp/ft squared (if I remember
the units correctly). One may use the square root of the film speed as
the anchor aperature and the reciprocal of the light meter reading is
the shutter speed. That sets the EV and then you slide the scale as
depth of field or action require. A nice feature.
Mitch Winkle [o]
[email protected]
AC4IY
----- Original Message -----
From: "stevegangi" [email protected]>
To: [email protected]>
Sent: Wednesday, January 02, 2002
Subject: [medium-format] Re: oops...Weston Light meter
I have the instructions for the Weston Master II Model 735
Universal. It does not give the conversion chart, but I found it on
the web once while doing a Google search for "Weston Master" and it
was so easy to remember that I didn't need to write it down. As I
use a lot of TMax 100 at an E.I of 100 (too lazy and too many cameras
lens/shutter combinations to bother testing every one for it's own
"personal speed"), all I do is set the "speed" on the meter to the
next slower speed (80). For black and white, the U and O postions
give an 8 Zone spread. For color, the A and C positions give a 3
Zone spread (good for shooting slide film and Polaroids). In
addition, I have tiny stickers on the meter to mark Zones 3 and 7,
just like I put on my spotmeter.
From: "maf" [email protected]>
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Hassy prism meter finders
Date: Wed, 3 Oct 2001
Denny is correct (cannot meter correctly through the lens to compensate for
many filters) when using B&W film. This is particularly true for orange and
red filters.. Here is a quote from Ilford on their film data sheets:
"With some automatic exposure cameras, the correction given for deep red and
orange filters can produce negatives under exposed by as much as 1 1/2
stops."
Also consider that TMAX 100 film has a much different blue sensitivity than
other films (even other Kodak films) and is like taking pictures with a
medium yellow filter even when no filter is being used. Therefore, no meter
(unless it had switch based on what exact film brand you are using) could
expose correctly for both TMAX 100 and Ilford Delta 100.
Another significant factor is the nature of the light. Where I live in
Colorado, there is much more blue light than most other places, and
minus-blue filters (yellow, orange, and red) require a higher filter factor,
especially if one needs to obtain any detail in the shadow areas. So the
best way is to do your own testing for filter factors. But if you go on a
trip to Colorado (or other similar geography) you might want to give a 1/2
stop more exposure (on a bright sunny day) than normal (plus the filter
factor) and cut your development a bit. Obviously, none of the above advice
applies to color film.
"k8do" [email protected]> wrote...
>
> Actually, meters don't see the world like film does, so that is an
> innaccurate way to adjust exposure... I simply apply the correction factor
> for the filter on the taking lens to the meter setting... i.e. a filter
> factor of 2X means that 100 speed film is set for 50 on the meter... Or a
> red filter with a 4X factor means that the meter is set for 25 speed...
>
> Denny
>
> "Q.G. de Bakker" [email protected]> wrote
> > radiojohn wrote:
> >
> > > Then there is the Rollei 2.8 GX with a TTL meter in the TOP lens!
> >
> > Silly thing to do, isn't it?
> > Every time you want to make an exposure when using a filter you need to
> put
> > the filter on the top lens first to meter, than transfer it back down to
> the
> > taking lens. Over and over again.
From: "Wayne Sircoulomb" [email protected]>
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Bronica SQAi
Date: Sat, 13 Oct 2001
35mm camera meters were biased to overexpose by one half to one f-stop.
Kodachrome slide film's speed was set so the latitude allowed about two
stops of over exposure and only a half atop under exposure. Kodak wanted to
rate the film higher so that it would sell better. To allow the
photographer better use of the latitude, 35mm TTL meters were calibrated to
overexpose 1 stop. When tested against a hand held or spot meter on an 18%
gray card all the Nikons I have used in the last 25 years have exhibited
this tendancy. I expect Olympus cameras were biased the same. I believe
that Ansel Adams wrote about this in one of his five classic books on
photography. When you use negative film you also got good results because
the latitude was so wide compared to slide film. Hand held meters do not
have this bias, but many medium format photographers test each type of film
they use to match it to their particular equipment.
Wayne
"k8do" [email protected]> wrote
> I used an OM2 for 20 years.... It did not matter what the film was, BW /
> Ektachrome / etc., the exposures were right on (if I did my part)...
>
> Denny
>
> "T P" please.reply@newsgroup> wrote
> > Karen Nakamura [email protected]> wrote:
> > >
> > > The other problem with TTL/OTF flash systems is that the reflectance Off
> > > The Film depends greatly upon the film brand and type being used. Just
> > > look at the leaders of some different films, there's at least a 1 stop
> > > difference between the lightest and darkest. So you have to calibrate
> > > your flash TTL to the film you're using.
> >
> > Hi Karen,
> >
> > If this were true, no-one would be using TTL auto flash!
> >
> > When Olympus developed their 35mm OTF metering (both ambient and flash)
> > in the 1970s, they found that the reflectance values of nearly all the
> > 35mm emulsions they tested were within 1/3 stop. That was before OTF
> > metering was in common use, and I suggest most of the newer emulsions
> > have had OTF metering very much in mind at the design stage.
> >
> > --
> > Best regards,
> > TP
Date: Tue, 23 Oct 2001)
From: Edward Meyers [email protected]>
To: Erwin Puts [email protected]>
Subject: Re: Newsletter #30
As far as I know, some of the European meters are calibrated
for a 20 percent, not 18 percent gray.
2. you don't mention the 120 rollfilm problems. Beginning of the
roll the film is held flatter than the end of the roll. Also,
If the film is held in a (hasselblad..for example) roll holder
where the bend for the next exposure is held for some time before
advancing, there will be a non-flat condition causing an eneven
sharpness throughout the frame. Rollfilm holders which don't
have this pre-exposure bend hold film flatter and better...usually.
Ed
From: [email protected]
Date: Thu, 10 Jan 2002
To: [email protected]
Subject: Re: [Rollei] metering with 3.5F tlr
> Defective cell. This is the usual symptom. This seems to happen
> eventually to all Selenium cells. I don't know the actual cause of the
> change although Selenium cells are not tolerant of heat or of moisture. The
> cell is usually sealed when made but the seal can break down with time
> letting some moisture in causing the cell to fail.
According to my friend in the semiconductor industry, the failure
mechanism is corrosion / failure of the front metalisation.
Richard
Date: Mon, 05 Nov 2001
To: [email protected]
From: Richard Knoppow [email protected]>
Subject: Re: [Rollei] Rolleiflex Exposure Chart Error?
you wrote:
>
>--- Rich Lahrson [email protected]> wrote:
>> Now, is this only true on the T? Do other
>> models show the
>> correct progression?
>
>Rich,
> I suspect what you are seeing is the progression
>chart of the "old" ASA. There were two such, one
>supplanting the other, with less of a "fudge factor"
>built into the film speeds of the latter. It had been
>assumed that the user was less than ideally
>experienced in the use of meters and in how to apply
>the film speed properly, therefore, most films were
>under-rated in speed to insure that the films didn't
>end up under-exposed (a very common occurence, back
>then). The change-over, as I recall, was sometime in
>the early '50s or so, and I am sure Rollei wasn't
>about to recall all their unsold cameras to change the
>plates, sooo, most, if not all made with the old ASA
>charts got to market even long after the change. Has
>anyone explored this correlation before? If so, does
>it coincide with the accepted serial number
>progression, specifically, the time of the change and
>the accepted date of camera/lens manufacture? It would
>be interesting to see if they agree. Of course, it
>could just be a collosal waste of time and energy,
>too.
>Just some idle noodling.
>
>Jon
>from Deepinaharta, Georgia
The first ASA speed system was an adaptation of the Kodak system worked
out by Lloyd A. Jones of Kodak labs. Speeds in Kodak numbers were published
by Kodak beginning about 1940.
Jones system was based on long research on how much exposure was needed
for an "excellent print". Some very large double blind tests were done to
judge what consitituted an excellent print.
Jones system was based on a a minimum gradient in the toe. This point was
measured on the basis of the toe contrast rather than on a fixed minimum
density. The minimum was the point where the gradient or gamma of the tow
was 1/3rd that of the average gradient over a log 1.5 density range. So,
the system took into account the shape and extent of the toe region.
This tended to set exposure at a level where adequate shadow detail was
produced at a minimum exposure.
The reason for setting minimum exposure was that grain is reduced and
sharpness is increased over negatives with greater exposure. Jones found
that increasing exposure from this point had little or no effect on tonal
rendition up to very large overexposure.
When the Kodak system was adopted by the ASA a 2.5X safety factor was
included. The reason given in Kodak literature is that it was to compensate
for underdevelopment in photofinishing plants, evidently very a very common
problem at the time. Probably the idea was that, since overexposure by this
much had no effect on print quality, it would insure that an image was
gotten by amateur photographers. This system was adopted by the ASA in
about 1943 and modified somewhat in 1946. The safety factor tended to
result in excessively dense negatives. Kodak's literature of the time
specifies that speed can be doubled without loss of quality when exposure
and processing is done carefully.
Kodak speeds do not have the safety factor. Old Kodak speeds translate
into modern speeds by dividing by two, and into the old ASA speeds by
deviding by four.
The Jones minimum usable gradient method of speed measurement is very
difficult to do reliably. In about 1958 the ASA adopted the DIN method of
speed measurement. This is essentially the system in current use.
The DIN system is based on a fixed minimum density (Log 0.1 above fog and
base density) and is based on a fixed gamma. The 1958 system had an 1.5X
safety factor effectively doubling the speeds of all films.
The ASA did a survey of films made at that time to determine the
difference in measureed speed between the DIN system and the Kodak system.
They decided that the differences were too small to warrent the substantial
additional difficulty of the Kodak system measurements.
Since that time there have been a number of changes in the ASA, later ISO
system. The original specified a developer, the formula for which was
included in the standard. The current version does not specify a developer.
The manuacturer can use any developer desired but it must be specified with
the resulting speeds.
Since the ISO system is based on a fixed average gradient it is not valid
for other degrees of contrast. The speed will be found to go down when the
film is developed to a lower contrast and to go up when developed to higher
contrast.
This system is used only for B&W negative films for still cameras.
Reversal film, color film, motion picture films, all have separate standards.
Its interesting that c.1946 there were a lot of "magic" developers
advertised which claimed to increase film speed by two stops.Well, they
did, but so would any good developer. Based on the original ASA speed they
could double or quadriple speed because the film was already a stop faster
than the speed indicated plus all films have about a one stop underexposure
latitude from the speed without a safety factor. All of these developers
disappeared quickly after the second ASA system, without the large safety
factor, was adopted.
Now, progression the original ASA speed, Kodak speeds, Weston speeds,
General Electric speeds, are all arithmetic so the numbers are the same.
ASA or current ISO speeds can be used on old meters by knowing the off-set
to use on the calculator. For Weston meters use the next lower number, for
old GE meters use the next highest number. GE adopted the ASA method in
1946 so even their older meters work on it. Weston continued to use their
own method for some time, don't have a date. I think the Weston Master III
is the first one with ASA speeds.
Older meters with ASA speeds use current ISO speeds, the correction is in
the speed number not the calulator. However, its easy enough to check using
the "sunny 16" rule.
The DIN sytem can be expressed in either arithmetic or log values. Log
values are common in Europe, arithmetic values in the USA and UK.
There have been a very large number of speed measuring methods proposed
and actually used over something over a century. The first reliable meters
used small bits of printing out paper. The exposure was made for a fixed
time and the paper compared with a standard chart. The next step was the
photoelectric meter, introduced about 1931. There is some controversey over
who exactly marketed the very first but the first one to become popular was
the Weston c.1935. Probably because Weston also introduced a workable speed
measuring method along with the meter and supplied the film speeds
themselves rather than relying on the manufacturers. These meters were easy
to use and had logical calculators. However they were rather expensive so
it took some time, and cheaper models, for them to become wide spread in
use.
----
Richard Knoppow
Los Angeles, CA, USA
[email protected]
From: Richard Urmonas [email protected]>
To: [email protected]
Subject: Re: [Rollei] Meter calibration; was metering with 3.5F tlr
Date: Fri, 11 Jan 2002
> I was wondering if there are any
> electronics inside the meter. I have read that each meter and cell came as
> set which are matched together. The most obvious way to do this is to
> change the response of the needle of the meter to match the current that
> the cell gives. If this is correct than it should be possible to adjust the
> meter electronics again to (partly) meet the different I-EV response of the
> defective cell.
Generally Selenium cell meters do not have any electronics inside. I am not
familiar with the exact circuit of the Rolleiflex design, but generally there
are three "variables" in the circuit. A resistor in series with the cell, a
resistor in parallel with the meter movement, and an adjustable shunt which
varies the sensitivity of the movement. A rollei may not have all of these.
(OK a fourth variable if you fiddle the zero setting of the meter movement).
A good selenium cell has an output current which is linear with light level
over most of its range. The meter will be set up to use this. As the cell
fails the most obvious symptom is the loss of output at high light levels.
It is relatively easy to make the meter read correctly at two points (low
light and lets choose "open shade"). However this will result in incorrect
readings at all other points. By using the three "variables" you could
possibly, if you are lucky, keep the error to a reasonable limit. Is it
worth the effort? NO! Remeber that a week or month or year later the cell
will have degraded further and so you would need to do it all again.
As for matched sets of cell and meter, it depends how Gossen designed it.
--
Richard Urmonas
[email protected]
Date: Wed, 14 Nov 2001
From: Charles Clemens [email protected]>
To: [email protected]
Subject: Diffusor for Gossen Pilot light Meter
Some (I hope) helpful information. The Gossen Pilot and Pilot 2 (also
known in Europe as the "Sixtino 2") are wonderful incident meters. As
they age about the first thing to fail seems to be the white plastic
sliding diffusor screen one uses to switch between incident and
reflected modes. It cracks or splits at it's joints. These can be
ordered from Gossen/Bogen parts department at 201-818-9500 for a mere
$2.00 each (plus $5.00 S&H) and are easy to self install.
--
Charles Clemens
[email protected]
Date: Thu, 10 Jan 2002
From: Jerry Lehrer [email protected]>
Subject: Re: [Rollei] Meter calibration; was metering with 3.5F tlr
To: [email protected]
Richard
Yes, the Weston Euromaster is still being
made in England. Most likely by Sangamo
Electric, who made a lot of the Weston
meters sold in Europe. Those meters can
be identified by their white meter faces. The
US meters have black faces. (Useless trivia,
isn't it?)
Westons of certain models are very long
lived. I have two original Weston Master
715's, probably made in the late '30s, which
are spot on in calibration. I would assume
that the cells are well sealed against humidity.
Jerry Lehrer
Richard Knoppow wrote:
>you wrote:
> >I'm told the russians are still making selenium cell meter variants,
> >presumably they also have huge warehouses full of parts for them too? ;-)
> >
> >and what about the chinese? Surely they have the right technology to help us?
> >
> >grins ;-) bobm
> >
> Isn't a version of the Weston still made in England? These are Selenium
> meters. Weston had a patent on cell construction. Old Weston meters seem to
> hold up better than other brands.
> ----
> Richard Knoppow
> Los Angeles, CA, USA
> [email protected]
Date: Thu, 10 Jan 2002
To: [email protected]
From: Richard Knoppow [email protected]>
Subject: Re: [Rollei] Meter calibration; was metering with 3.5F tlr
you wrote:
>> I was wondering if there are any
>> electronics inside the meter. I have read that each meter and cell came as
>> set which are matched together. The most obvious way to do this is to
>> change the response of the needle of the meter to match the current that
>> the cell gives. If this is correct than it should be possible to adjust the
>> meter electronics again to (partly) meet the different I-EV response of the
>> defective cell.
>
>Generally Selenium cell meters do not have any electronics inside. I am not
>familiar with the exact circuit of the Rolleiflex design, but generally there
>are three "variables" in the circuit. A resistor in series with the cell, a
>resistor in parallel with the meter movement, and an adjustable shunt which
>varies the sensitivity of the movement. A rollei may not have all of these.
>(OK a fourth variable if you fiddle the zero setting of the meter movement).
>
>A good selenium cell has an output current which is linear with light level
>over most of its range. The meter will be set up to use this. As the cell
>fails the most obvious symptom is the loss of output at high light levels.
>It is relatively easy to make the meter read correctly at two points (low
>light and lets choose "open shade"). However this will result in incorrect
>readings at all other points. By using the three "variables" you could
>possibly, if you are lucky, keep the error to a reasonable limit. Is it
>worth the effort? NO! Remeber that a week or month or year later the cell
>will have degraded further and so you would need to do it all again.
>
>As for matched sets of cell and meter, it depends how Gossen designed it.
>
>--
>Richard Urmonas
>[email protected]
A Selenium cell has linear _current_ output. For its light reading to be
exactly linear the meter must have zero input resistance. Possible with
electronic meters. The meters used on practical Selenium meters were
compromised between sensitivity and low resistance. The scale was
linearised by using shaped pole pieces in the meter.
I think part of what happens to meters which are damaged is an increase
in internal resistance. A series resistance causes compression of the
output as it increases.
----
Richard Knoppow
Los Angeles, CA, USA
[email protected]
From: [email protected]
Subject: Re: [Rollei] OT Weston Selenium meter is made by Megatron, England
To: [email protected]
Date: Fri, 11 Jan 2002
From Jerry Lehrer:
> ....Yes, the Weston Euromaster is still being made in
> England....by....
MEGATRON
Megatron Limited
165 Marlborough Road, London N19 4NE, UK
Tel: +44 (0) 20 7272 3739
Fax: +44 (0) 20 7272 5975
http://www.megatron.co.uk/homepage.html
http://www.megatron.co.uk/euromaster2/index.html
I had a Weston V repaired by them in 2000. They exchanged the selenium
cell, kept the meter and box and recalibrated the instrument:
re-started for another 20 years or so ;-)
BTW I'm sure you could ask Megatron, UK to rebuild a selenium cell for
a Rollei if you supply the defective one. The do produce a
comprehensive line of selenium meters. The price they would eventually
ask for a Rollei cell is another story.
--
Emmanuel BIGLER
[email protected]>
From: [email protected]
Subject: Re: [Rollei] slight OT custom-made selenium cell, Megatron, UK
To: [email protected]
Date: Fri, 11 Jan 2002
about selenium cells by Megatron, UK:
http://www.megatron.co.uk/stock-listing/index2.html
"Special Sizes and Shapes can be cut to order; minimum price (for 1) =A31=
8.00"
Sounds like a good starting point to rebuild a Rollei selenium cell,
if Gossen does not want to continue the service, isn't it ?
--=20
Emmanuel BIGLER
[email protected]>
Date: Fri, 11 Jan 2002
From: Sven Keller [email protected]>
To: [email protected]
Subject: Re: [Rollei] slight OT custom-made selenium cell, Megatron, UK
Emmanuel,
this is a nice web site with some good information - quite the opposite to
www.gossen.de.
I have called Gossen this morning and tried to talk them into accepting an
order for 5,000 Rolleiflex selenium cells but they refused.
Instead they told me that the only remaining German manufacturer of selenium
cells (whom they got the Rolleiflex cells from at the time) has long quit
business. Gossen still make two selenium meters, one (the Bisix) about to be
discontinued because the Japanese supplier of the cells stopped making them.
The cells for the other one (Sixtino) they get from .... Megatron.
If I understand correctly what Megatron writes they produve cells with two
different sensitivities (0.07 and 0.03 mA/Lux/sqcm). So even if they are able
and willing to make a cell that one could fiddle into a R'flex meter cell
housing we would first need to obtain information regarding the sensitivity of
the Rollei meter instrument to carry on.
... this becomes complicated.
Sven Keller
> about selenium cells by Megatron, UK:
>
> http://www.megatron.co.uk/stock-listing/index2.html
>
> "Special Sizes and Shapes can be cut to order; minimum price (for 1)
> =A318.00"
>
> Sounds like a good starting point to rebuild a Rollei selenium cell,
> if Gossen does not want to continue the service, isn't it ?
>
> --
> Emmanuel BIGLER
> [email protected]>
Date: Sat, 12 Jan 2002
From: Rich Lahrson [email protected]>
To: [email protected]
Subject: Re: [Rollei] slight OT custom-made selenium cell, Megatron, UK
Hi Todd,
I've seen one of these 'new' old stock complete meters for the F on
eBay sell for about $225. So, that's what people will pay, and there ar=
e
only a handful who want one.
Cheers, Rich Lahrson
[email protected]
Todd Belcher wrote:
> Actually, I bought a few of those - it was about 10 years ago and I was told
> they were new "old stock" of leftovers that Rollei, not Gossen, had lying
> around. They were found in a storageroom or something to that effect and
> Rollei offered them to Club Rollei.
>
> todd
>
> Didn't Gossen supply Club Rollei with a run of F series selenium cells five
> years back or so? Or is this another example of Ian Paker, well,
> Parkerizing?
>
> Marc
>
> [email protected]
Date: Sat, 12 Jan 2002
To: [email protected]
From: "[email protected]" [email protected]>
Subject: [Rollei] custom-made selenium cell, Engineering Tasks
It should be possible to replace the selenium cell by a CdS or Sii cell,=20
place the neeed batterie inside the huge available space in the mirror=20
housing and keep using the original meter.
Only the linearity of the systems shal to be matched maaybe by some=20
lectronic components. But that shoudl be an easy task.
Who will be the fist one to carry out tests with a Si cell to fix to the=20
original meter?
Dirk
you wrote:
>Hi Todd,
>
> I've seen one of these 'new' old stock complete meters for the F on
>eBay sell for about $225. So, that's what people will pay, and there are
>only a handful who want one.
>
> Cheers,
>
>
>Rich
>Lahrson
>
>[email protected]
>
>Todd Belcher wrote:
>
> > Actually, I bought a few of those - it was about 10 years ago and I was
> told
> > they were new "old stock" of leftovers that Rollei, not Gossen, had lying
> > around. They were found in a storageroom or something to that effect and
> > Rollei offered them to Club Rollei.
> >
> > todd
> >
> > Didn't Gossen supply Club Rollei with a run of F series selenium cells five
> > years back or so? Or is this another example of Ian Paker, well,
> > Parkerizing?
> >
> > Marc
> >
> > [email protected]
From: [email protected]
Subject: Re: [Rollei] OT selenium cells, no batteries
To: [email protected]
Date: Mon, 14 Jan 2002
From Richard K.:
> ....also makes Selenium meters...a very useful meter, BTW, either as
> a main or as a backup. Needs no batteries.
... and a selenium meter, at least according to Megatron, works fine
even in extreme cold weather ; my understanding is that the
current/voltage characteristics does not change so much that the meter
becomes useless in a polar expedition. However modern lithium cells
also work fine in cold weather.
--
Emmanuel BIGLER
[email protected]>
To: [email protected]
From: Mark Overton [email protected]>
Date: Mon, 14 Jan 2002
Subject: Re: [camera-fix] Walz Envoy M35
Charles Monroe wrote:
>
> You might try
>
> Quality Light Metric
> 7095 Hollywood Blvd., Rm. 550
> Hollywood, CA 90028
>
> 1-323-467-2265
>
> They do have the selenium cells for the old Weston
> Master II light meters and they may have others.
I'll add that Selenium cells can easily be cut down to size with
a hacksaw, as long as you don't cut off the part with the front
connector. I've done it.
Mark Overton
Date: Wed, 09 Jan 2002
To: [email protected]
From: Richard Knoppow [email protected]>
Subject: Re: [Rollei] metering with 3.5F tlr
you wrote:
>My 3.5F's meter is non-linear, about a stop low in bright light.
Defective cell. This is the usual symptom. This seems to happen
eventually to all Selenium cells. I don't know the actual cause of the
change although Selenium cells are not tolerant of heat or of moisture. The
cell is usually sealed when made but the seal can break down with time
letting some moisture in causing the cell to fail.
----
Richard Knoppow
Los Angeles, CA, USA
[email protected]
From: Lassi [email protected]>
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Cheap Light meter
Date: Mon, 07 Jan 2002
Xochitl wrote:
>
> "Q.G. de Bakker" [email protected]> wrote
> > Leonard Evens wrote:
> >
> > > I got a Weston meter about 1965. By 1980, it no longer produced
> > > accurate results. Moreover, I subsequently learned that such behavior
> > > was to be expected with a selenium meter. I don't remember the
> > > mechanism whereby such a meter loses sensitivity. I thought it was
> > > fundamental, but it could have something to do with the way it is
> > > manufactured, and there could be ways to prevent it that were introduced
> > > later.
> > > [...]
> >
> > Selenium cells life forever, without any change. That is, as long as they
> > are perfectly sealed.
> > The sealing however can, and very often will, get damaged, if not
> > mechanicaly then by corrosion.
>
> The meter on my Rolleiflex 3.5F is still totally accurate. I bought it
> from someone who kept in the dark for 20 years!
Keeping it in the dark helps. The problem is ultraviolet, which tends to
cause problems to selenium crystals. When selenium was used in the solar
panels of satellites, it was supposed to lose about 2% of its power
annually (IIRC). Satellites orbit in a harsh radiation environment when
compared to light meters, but the phenomenon is the same.
Since the cell loses its sensitivity linearly, and film sensitivity is
logarithmic, the meters have an in-built lin/log-converter. For example,
in Zeiss Ikophot it is a mechanical gizmo. Keeping the calibration curve
meaningful is a major problem.
-- Lassi
To: [email protected]
From: Ron Schwarz [email protected]>
Date: Wed, 05 Dec 2001
Subject: Re: [camera-fix] Re: (silicon cells) Digest Number 174
you wrote:
>Everett wrote:
>> Radio Shack sells a silicon solar cel that will work cat# 276-124 can be
>> cut on three sides to fit. the soldering is trickey and the output is
>> little higher but it will work! What the heck! The meter will have to be
>> calabrated anyway!
>
>Have you figured out a way to cut silicon cells? When I tried it, it
>broke into pieces like a thin piece of glass.
They *are* glass! You could probably cut them with a glass cutter--
carefully.
Silicon cells use a glass substrate, unless they're the newer (and lower
efficiency, but cheaper to make) amorphous silicon cells, which IIRC are
usually "printed" on sheet metal.
Are you sure someone is suggesting silicon to replace selenium? The output
is much higher, the spectral curves are quite different (selenium is a
better match for photographic applications than anything else, i.e. CdS,
etc.), and I suspect the illumination/output curve is different too.
"Silicon Blue" photocells used in modern cameras use a *tiny* chip of a
silicon cell, with a filter to correct its spectral sensitivity, and, an
amplifier to read the cell's output. The cell is used as a signal rather
than a power source. (Selenium cells are used as a power source to
directly drive a galvanometer; Silicon "blue" cells are used as a signal
source to drive an amplifier input, and CdS cells are a variable
resistance, to vary the amount of current sent to a galvanometer from a
battery.)
/end_tiresome_tutorial (G)
To: [email protected]
From: [email protected]
Date: Wed, 5 Dec 2001
Subject: Re: [camera-fix] Re: (silicon cells) Digest Number 174
[email protected] writes:
> I didn't realize that silicon's color-response was so different
As I understand it, silicon cells are treated to alter the response. The
treated cells are call "blue silicon cells".
Sometimes it is possible to paint over portions of the cell with a "Sharpie"
black marking pen to reduce the output. As you undoubtedly know, most
rangefinder cameras that have the cell mounted in the lens mount have a
rotating ring with varying size "apertures" to increase or decrease the
output of CDS cells. Blocking out a portion of the cell with black ink would
have the same effect. And if I recall correctly Thomas Tomosy mentions the
marking pen trick in one of his camera repair books.
To: [email protected]
From: "camfix55" [email protected]>
Date: Thu, 06 Dec 2001
Subject: [camera-fix] Re: (silicon cells) Digest Number 174
--- In camera-fix@y..., Mark Overton mark@s...> wrote:
> Yes, Everett suggested using silicon cells from Shadio Rack (I love that :-).
> I didn't realize that silicon's color-response was so different. But higher
> output is something I could fix with a resistor-divider, so that's okay.
>
> I've heard that Selenium is either less or more sensitive (can't remember
> which) to red than the human eye; is that your understanding? I've heard
> that Selenium can be off as much as 2 stops under tungsten light. So I was
> surprised to see how closely Megatron's Selenium curve matched the CIE
> observer.
>
> Mark Overton
>
> -----
>
> Ron Schwarz:
> >
> > you wrote:
> > >Everett wrote:
> > >> Radio Shack sells a silicon solar cel that will work cat# 276-124 can be
> > >> cut on three sides to fit. the soldering is trickey and the output is
> > >> little higher but it will work! What the heck! The meter will have to be
> > >> calabrated anyway!
> > >
> > >Have you figured out a way to cut silicon cells? When I tried it, it
> > >broke into pieces like a thin piece of glass.
> >
> > They *are* glass! You could probably cut them with a glass cutter--
> > carefully.
> >
> > Silicon cells use a glass substrate, unless they're the newer (and lower
> > efficiency, but cheaper to make) amorphous silicon cells, which IIRC are
> > usually "printed" on sheet metal.
> >
> > Are you sure someone is suggesting silicon to replace selenium? The output
> > is much higher, the spectral curves are quite different (selenium is a
> > better match for photographic applications than anything else, i.e. CdS,
> > etc.), and I suspect the illumination/output curve is different too.
> > "Silicon Blue" photocells used in modern cameras use a *tiny* chip of a
> > silicon cell, with a filter to correct its spectral sensitivity, and, an
> > amplifier to read the cell's output. The cell is used as a signal rather
> > than a power source. (Selenium cells are used as a power source to
> > directly drive a galvanometer; Silicon "blue" cells are used as a signal
> > source to drive an amplifier input, and CdS cells are a variable
> > resistance, to vary the amount of current sent to a galvanometer from a
> > battery.)
> >
> > /end_tiresome_tutorial g>
> >
Hi group;
I use a Dremel tool with a diamond wheel to cut the silicone photo cells. yes the selenium is sensitive to different colors but we are talking about a technoligy thats been arround before color film. I don't think we could find two people in this group that can agree on whats "blue" I survived in the printing business for over thirty years by looking at the size of a dot on color seperationes. I am color blind! The latest greatest superwhatumaycallit light meter is still limited due to the fact that we are converting light into electricity. The nice thing about B+ is that we can adjust it to get what you or I think is blue. Electricity is also color blind!
Nuff said Everett
To: [email protected]
From: Ron Schwarz [email protected]>
Date: Fri, 07 Dec 2001
Subject: Re: [camera-fix] Weston III
>My Mother's Weston Master III has a few probs. The needle does not settle
>on the
>0 position, it resides at about 25/1.6. Also in comparison to my Nikon F90,
>the Weston read
>200 and the Nikon 400 today. Is the scale in LUX? It doesn't say on the
meter.
Have you tried adjusting the zero-setting screwhead on the back? (It's not
really a screw, it has an off-center pin on the other side.) If you can't
get the range you need, you should be able to turn the hairspring on the
*front* part of the jeweled galvanometer movement. Be careful -- if you
make the meter too "tight" (or loose) by working both hairsprings toward or
away from each other, you'll change the meter's linearity.
One other possiblilty, which I've seen all too frequently over the years is
a tiny piece of metal "dust" -- sometimes it's a near-microscopic chip of
alnico that breaks off the magnet, sometimes it's just a random ferrous
metal filing that comes from God knows where. Anyway, what happens is that
it'll lodge itself (via magnetism) on the solid metal "drum" that the
galvanometer windings float over, and when the thin frame that holds the
windings touches the metal filing, the meter binds.
You can remove it (if you can see it) if you have a *very* steady hand, and
a needle, or toothpick, or very fine tipped tweezers, or something along
those lines.
Do *not* try to blow it out with compressed air of dust-off. The meter
movements are *very* delicate, and trust me, you do *not* want to have to
spend some quality time untangling the flat hairsprings or resoldering the
microscopic magnet wire in the coil. (Reserve those tricks for times you
*really* need them, like when someone drops a meter, or the coil burns out,
and you're getting *paid* to go through that kind of hell. g>)
To: [email protected]
From: Ron Schwarz [email protected]>
Date: Wed, 12 Dec 2001
Subject: [camera-fix] CDS Cell regeneration
I received the following from the Rangfinder List. I hadn't heard of this
trick before, I thought I'd pass it along here. There were two followups,
one from a guy who said he'd heard of it (Yepp. I've heard it mentioned a
few times. "Just put the camera/lightmeter in the sun for a few hours..."),
and the other said a tech tried it on his Oly XA to no avail.
Even if it only works in certain scenarios, it could be a godsend when
working with older "Parts NLA" equipment.
Along those lines, I think it should be possible to replace quite a few CdS
cells with "generic" off the shelf components. The main considerations
would be size and resistance characteristics. Off the shelf components are
available in a wide range of sizes and resistances, so I'd think the main
thing would be to gather up a list of resistance ranges of the cells used
in cameras and meters. I don't know how easy it would be to get that info,
I suppose if nothing else, people could measure the resistance of
known-good cells from cameras.
I'm musing on the above because I remember seeing a fair number of bad CdS
cells back when I was in the repair trade, and back then it wasn't too hard
to order replacements from the mfgrs. 9 times out of 10, they'd fail by
getting leakage, and show a "baseline" light level even in pitch darkness.
If anyone tries the technique described below, please report whether or not
it fixes 'em.
=============================================================================
To: [email protected]
From: "Robert J. Howard" [email protected]>
Subject: [RF List] CDS Cell regeneration
Date: Sun, 9 Dec 2001
Just had a CLA on my Leica CL I recently purchased. The light meter was
responding slowly. The technician said the CDS cell was weak and he
regenerated it my shinning a bright light on it for 3 days. He did not
replace it as he thought the parts might not be available. It seems to work
fine now. He recommended that I do the same, but for a brief period of
time if I let the camera sit up for more than a few weeks.
Anyone ever heard of this "fix"?
Robert Howard
To: [email protected]
From: "camfix55" [email protected]>
Date: Sat, 29 Dec 2001
Subject: [camera-fix] Re: (silicone cells) digest #174
Hi Group;
My loving wife was kind enough to buy me the "Nikon Camera Repair Handbook" for my birthday.
On page 126 Thomas Tomsey wrote "Radio Shack and Edmund Scientific carry silicon solar cells that might be a usable substitute for selenium. Electric and optical performance is close to that of selenium. The color response is actually better, i.e., closer to that of the human eye."
It is of great comfort to me in my old age to find at least one other person who can agree with some of my suggestions that some in this group find humorous.
Best wishes to all for a happy and sucessful new year! Everett
From rangefinder mailing list:
Date: Sun, 9 Dec 2001
From: "Robert J. Howard" [email protected]
Subject: CDS Cell regeneration
Just had a CLA on my Leica CL I recently purchased. The light meter was
responding slowly. The technician said the CDS cell was weak and he
regenerated it my shinning a bright light on it for 3 days. He did not
replace it as he thought the parts might not be available. It seems to
work fine now. He recommended that I do the same, but for a brief period
of time if I let the camera sit up for more than a few weeks.
Anyone ever heard of this "fix"?
Robert Howard
Date: Tue, 13 Nov 2001
To: [email protected]
From: Henry Posner/B&H Photo-Video [email protected]>
Subject: [Nikon] Re: measuring light
you wrote:
>IOW, if the average scene has a reflectivity of 18%, why
>manufacturers wouldn't calibrate meters to 18% gray?
Because while the average outdoor scene may approximate 18%, the average
indoor scene is closer to 12%. Can't have both. Anecdotes say that it was
Ansel Adams who drove Kodak to make the first standardized gray card 18%
instead of 12% so it would better conform to Zone V in his much-vaunted
Zone System.
--
regards,
Henry Posner
Director of Sales and Training
B&H Photo-Video, and Pro-Audio Inc.
http://www.bhphotovideo.com
Date: Wed, 24 Oct 2001
To: [email protected]
From: Henry Posner/B&H Photo-Video [email protected]
Subject: [Nikon] Re: F5 metering - 12% or 18%?
you wrote:
>I never discovered the source for the 18% gray
I have an article from the April, 1990 issue of Photomethods written by
William G. Hyzer, P.E. which discusses this in some detail. Photomethods is
now PEI and if they give me permission to reproduce their copyright
article, I will do so. The article does reference Kodak's 1960 publication
# E75, Color Photography Outdoors, and points out that 12% is average
outdoor reflectance, but 18% for indoor scenes.
As I said, if permitted, I will reproduce the article in its entirety.
Also, at http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=000TFP Tom
Johnston, in a long0ish conversation on this same topic, references
additional articles: Exposure Metering Myths, DCCT, Jan/Feb 1992. And, TECH
TALK, Photomethods, August 1991.
--
regards,
Henry Posner
Director of Sales and Training
B&H Photo-Video, and Pro-Audio Inc.
http://www.bhphotovideo.com
From nikon mailing list:
Date: Thu, 30 Aug 2001
From: John Albino [email protected]
Subject: Re: expo/disc by George Wallace
Sebastianwrote:
>Maybe can someone tell me how it is with this device... I was at
>http://www.expodisc.com/ but there is no enough information for me.
>Can I use it instead hand light meter, or spot meter?
>What else I can do with it???
>It is very interesting...
What the Expo/Disc does is effectively to turn your camera's built-in
reflected light meter into an incident meter. It does so in the same
essential manner that many hand-held reflected light meters perform
incident readings -- by placing a calibrated semi-translucent "object" over
the meter's sensing cell.
Reflected meters as old and as classic as the early Weston Master series
used to come with a whitish plastic device which fitted over the sensor
cell and then the meter was used as an incident meter.
An "incident meter" is called that because it measures the light falling
onto it from a light source (light "incidence") rather than being reflected
back from a subject.
The Expo/Disc fits onto the front of a camera lens. The camera then is
placed in the subject's position (or similar light) and pointed back,
either at the light source or at the eventual taking position of the photo.
(Whether pointed at the light source or the camera taking position is
mostly a matter of technique and personal calibrations and needs.)
Although the description on the web site is pretty Spartan, it does
describe several uses of the Expo/Disc, perhaps the most exotic of which is
the "flashing" of film in order to increase tonal range. Flashing is a very
old technique not much used any more. It also used to be used to increase
the effective speed of film for old-time "available darkness" shooting.
There are both pre- and post-flashing techniques. Essentially, the film is
exposed to a brief (extremely brief) "flash" of pure light which can either
pre-sensitize the film for additional effective film speed, or increase the
threshold of a film's characteristic curves to spread out the tonal range,
thus allowing for the ability to capture a more contrasty scene than
normally possible. Although lots of experimentation is necessary to achieve
one's personal goals, once established it can be an effective technique. I
personally have not made much use of it, and only used it enough many years
ago to understand the basics of how it worked, but not to become any kind
of "expert" with the technique.
Also described on the Expo/Disc page is probably the simplest use of the
device -- as a "Sunny-16" checker. Any well-calibrated incident meter
should be much more consistent with Sunny-16 than a reflected meter, since
the reflected meter will have many variables introduced into the metering
(including what the meter is pointing at, both color and reflectivity-wise).
As a tool, the Expo/Disc is not that expensive, and certainly could make an
interesting "toy" to play with for a different understanding of exposure
and how one's camera metering system really works. For all practical
purposes Matrix Metering would be useless, and probably prone to wrong
readings, if used with such a device. Spot metering also probably wouldn't
work well. I'd guess the broadest-reading in-camera meter would gain the
best results, although, like most everything photographic, actual
individual testing and calibration techniques would lead to the best
results.
I've never personally used an Expo/Disc, but (long before I ever heard of
the device) tried to make something similar back in the '60s, and found
that if one spent enough time and effort, such a technique could produce
very good results.
--
John Albino
mailto:[email protected]
From nikon mailing list:
Date: Thu, 30 Aug 2001
From: Ron Schwarz [email protected]
Subject: Re: expo/disc by George Wallace
>I've never personally used an Expo/Disc, but (long before I ever heard of
>the device) tried to make something similar back in the '60s, and found
>that if one spent enough time and effort, such a technique could produce
>very good results.
IIRC Topcon sold something like that, but dome shaped, back in the '60s for
use with their cutting edge TTL SLR.
From nikon mailing list:
Date: Thu, 30 Aug 2001
From: John Albino [email protected]
Subject: Re: expo/disc by George Wallace
Ron Schwarz wrote:
>IIRC Topcon sold something like that, but dome shaped, back in the '60s for
>use with their cutting edge TTL SLR.
I kind of remember that. The Topcon was the very first TTL SLR, and was
really a very strong beast. I think what killed it was that Nikon had a
much more complete system, and ultimately that proved more important than
"who was first."
Also, if I, too, recall correctly, one of the photo magazines at the time
had an article or two on making your own in-camera incident meter by using
half a ping-pong ball on the lens.
Something else I experimented with at the time was making my own
pseudo-TTK meter by trying to calibrate my Gossen Luna-Pro with taking a
reading
through the viewfinder of my (plain-prism) Nikon F. This was before Nikon
came out with a TTL prism, which I couldn't have afforded, anyway, since I
already had busted the bankroll getting my F. g> Anyway, the Luna-Pro
certainly was sensitive enough, and indeed I could make it work, but it
wasn't very effective since it wasn't really very feasible for hand-held
readings. The camera pretty much needed to be mounted on a tripod, and it
took some time to take the pseudo-TTL reading, and if I had that much time
available I could just as easily gone right up to the subject and taken a
direct reading. {g}
--
John Albino
mailto:[email protected]
From nikon mailing list:
Date: Thu, 30 Aug 2001
From: [email protected]
Subject: Re: Wallace Expo-disc
[email protected] writes:
Maybe can someone tell me how it is with this device... I was at
http://www.expodisc.com/ but there is no enough information for me.
Can I use it instead hand light meter, or spot meter?
What else I can do with it??? >>
As I recall, it is/was available in various popular filter thread sizes - you
just screwed it to the filter thread and bingo - an incident cone. I think
the supposed advantages of having it on various focal length lenses are
somewhat overstated, though.
Being translucent, it serves virtually no other photographic purpose, however
I do recall an Expo-Discus Olympic trial in the warehouse at Jessops' old HQ.
These little buggers fly about 50' when you get the knack.
Kind regards
Peter
From nikon mailing list:
Date: Thu, 30 Aug 2001
From: Rich Evans [email protected]
Subject: Re: expo/disc by George Wallace
by placing a calibrated semi-translucent "object" over the meter's sensing cell
WOW!! Now I know what I can use all those transluscent Nikon body caps for!
;-)
Regards,
Rich
From nikon mailing list:
Date: Thu, 30 Aug 2001
From: "Stu Turk" [email protected]
Subject: Re: expo/disc by George Wallace
----- Original Message -----
From: John Albino [email protected]
> Also, if I, too, recall correctly, one of the photo magazines at the time
> had an article or two on making your own in-camera incident meter by using
> half a ping-pong ball on the lens.
Wonder if a square of diffused or milk-white plastic slipped into a
filter holder would work?
From nikon mailing list:
Date: Thu, 30 Aug 2001
From: [email protected]
Subject: Re: expo/disc by George Wallace
I understand a styrafoam cup works about the same when held in
front of the lens.
GeoW
From nikon mailing list:
Date: Thu, 30 Aug 2001
From: Nikon Cameras [email protected]
Subject: Re: expo/disc by George Wallace
If anyone has access to the filter kits sold by Honeywell for the Strobonar
"potato masher" type of strobes (or can find one set in the back of some photo
store that sold these 1960-70 units), you can take the opal covered egg-shaped
filter and epoxy it to a Nikon snap-on lens shade. This will give you an
equivalent incident light meter for a Nikon camera. I used to use this until
the snap-on lens hood fell off and was lost. It came in a kit of several
filters (red, orange, etc) but you want the opal-colored wide-angle diffuser
one. I own a Weston Master V with incident cone attachment that is 40 years
old and is still going strong. You can also get some opal-colored plexiglas at
some do-it-yourself centers or some art-supply centers, cut it to size (52mm,
62mm, 72mm, etc.) and attach this to a filter with the glass removed using
epoxy.
From leica mailing list:
Date: Sun, 9 Dec 2001
From: "Robert J. Howard" [email protected]
Subject: Regenerating CL CDS cells
Just had a CLA on my Leica CL I recently purchased. The light meter was
responding slowly. The technician said the CDS cell was weak and he
regenerated it my shinining a bright light on it for 3 days. He did not
replace it as he thought the parts might not be available. It seems to work
fine now. He recomended that I do the same, but for a brief period of time
if I let the camera sit up for more than a few weeks.
Anyone ever heard of this "fix"?
Robert Howard
Page started on October 20, 1999