See these links for related medium format cameras
and resources,
including an extensive series of postings articles on camera repair
at the bottom of the MF Articles page.
rec.photo.equipment.medium-format
From: [email protected] (Mark Langer)
[1] Re: People using old folders?
Date: Wed Apr 15 1998
JCPERE ([email protected]) wrote: > An Ansco Speedex Special with Apotar lens recently sold for around $68 on Ebay. > I think any Ansco with a Solinar lens will sell for $100+ ( I have never seen > one on Ebay). Looks like a lot of interest in these cameras. Hold on to yours > as soon Ansco's will be selling for Bessa 11 prices.
The Solinar ones do come up on ebay, but rarely. Prices on ebay have been
escalating wildly. I sell cameras on ebay, but usually buy them
elsewhere. I've been getting $50 -$60 for Agfa/Anscos with Apotars on
ebay, but they are readily available for much less. They are not hard to
find for $10-$15 if they need a little work. An e-mail buddy put a "WTB"
ad on several internet newsgroups, and was swamped with bargain Agfa/Ansco
folders in excellent condition. I pick mine up at yard sales and from
small town photo dealers. Recently got an Isolette III with f3.5 Solinar
at a camera show in Montreal for the equivalent of $30 US without any
haggling.
What makes so many Agfa/Anscos cheap is that they invariably have the
rangefinder or the lens focus frozen by dried lubricant, which on the
Agfa/Anscos dries to a bilious green. Frozen focus can be fixed by
spraying Radio Shack Electrical Contact Cleaner generously all around the
focus ring, wrapping the lens with some fabric, carefully tightening a
wrench around it and carefully turning. If it doesn't move, keep
repeating the treatment with the contact cleaner. Once it is moving
freely, get the focus ring off (you have to remove the tiny screws around
the circumference), and clean up all the dried goo with a solvent and a
q-tip. You may want to calibrate the focus by using a piece of ground glass
or even waxed paper at the film plane and focusing the lens at infinity.
When an object at least 1/2 mile away is in sharp focus on the ground
glass, replace the focus ring so that it indicates infinity and tighten up
the screws.
For the rangefinder, unscrew the top of the camera. The rangefinder
mechanism is in a box, which you are unlikely to have to tamper with.
Unscrew the little rangefinder adjustment wheel on the back of this box
and clean out all the goo. Point the camera to an object at least 1/2
mile away and focus the rangefinder on it. Screw the wheel back on,
making sure that the infinity mark is pointing straight up. Bingo, your
rangefinder is accurate and perfectly calibrated to your lens.
Agfa/Anscos are also prone to light leaks on the bellows. Patch these
with a mixture of fabric glue and black pigment (easily available at art
supply stores). Thin with water to get an even consistency. Let it dry
for a few hours before refolding bellows.
About an hour or two of work can return most non-functional Agfa/Anscos to
good working order, and turn a $10-$15 investment into a really good camera.
Mark
Mark Langer
Email address: [email protected]
rec.photo.equipment.large-format
From: [email protected] (Richard Knoppow)
[1] Re: HELP: Lubricating older cameras
Date: Thu Apr 30 1998
nwester [email protected] wrote:
>I recently purchased two post war European medium format folding >cameras. They are both extremely compact and cute. To focus these >cameras the lens mount holding the front element rotates inside a >housing which then screws into the shutter. The grease in the threads of >these mounts had turned to glue and it took considerable effort to get >them apart. Any ideas on the type of grease to use? Lighter fluid >cleaned them up but I think I need something thicker. I am now >recalibrating the focus and would like to finish this project and start >shooting. >Thanks, Craig Wester
Microtool lists a helical grease that sounds like the right stuff.
Their product number is 744. Their web page is:
http://www.micro-tools.com You might check with them to see if this
is indeed a suitable grease.
---
Richard Knoppow
Los Angeles, Ca.
[email protected]
Date: Wed, 04 Aug 1999
From: [email protected] (Lyndon Fletcher)
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Repairing the focus on an Agfa Isolette I
Barbarosa [email protected]
wrote:
>Is this the right forum to discuss repairing an old 6x6 camera from the >50's? > >I just bought an Agfa Isolette through eBay and the camera seems is >great shape except for one thing. The focusing mechanism is jammed >pretty thoroughly. As the camera is only worth about $30, taking it to >a repair shop doesn't seem economic. Does anyone have any thoughts on >how I might go about repairing this myself? > > B
Ok,
The lubricant has hardened. This is what you do about it.
First, the lense is not supposed to unscrew. If someone tells you that
that is the way the camera focuses then ignore them because it isn't
true. The screw thread is just there to hold the lense on it is not a
Helical focussing thread. This is good because it means there is only
one start point. As a result lenses can be removed without having to
setup the focus again.
1) Remove the lense by unscrewing it.
2) Turn it over and lay it on it's front element.
3) You will see that the aluminium dial for adjusting the focus is
concave at the back. Fill this channel with contact cleaner being
carefull not to get any on the rear element of the lense.
4) Wait a couple of hours.
5) Holding the treads in one hand and the aluminium focus collar in
the other, try to twist them in opposite directions. After a couple og
hours soaking they should move with a bit of effort.
6)Work them until they are free.
7) Using a q tip smear a little grease around the inside of the
aluminium channel. Work the focus as before and wipe away the excess.
8) replace the lense.
Lyndon
From: Struan Gray [email protected]
Newsgroups: rec.photo.equipment.medium-format
Date: 19 Jul 2000
Subject: Re: Adjusting scale focus of an old folder
Robert Monaghan, [email protected] writes:
> if you use the laser distance measuring gizmos > ($40+) you may be amazed at how accurate your > lenses are
I've been having fun with laser pointers recently, in an attempt
to come up with a focussing scheme which will work with oddball
homebrew lenses on systems with no reflex viewing or distance scales.
If you can get hold of a focussing screen with a microprism patch
(or a piece of glass embossed with the right pattern) put that on the
film rails and shine a laser pointer through it and out of the lens.
The microprisms split the laser into four (or more) beams, diverging
from a single point in the focal plane. When the lens is correctly
focussed on an object the four beams combine to form a single spot.
At any other distance you get four individual spots. (If your 35 mm
SLR has a microprism patch you can test this by shining the laser
pointer in through the viewfinder).
Another option is to get one of those pointers with screw-on
diffractive elements that produce shapes and patterns. If you can
find some way of ensuring that the diffractive element is at the focal
plane this works even better than the microprism technique. Edmund
Scientific have 'pattern generators' listed in their online optics
catalogue, but no details (my paper catalogue is too old). *If* this
is what I think it is (the diffractive element in sheet form), a piece
of this at the film plane will do the job nicely.
If you can't do either of those, you can use plain ground glass at
the film plane and shine the laser pointer onto it. The lens casts a
(somewhat dim) image of the front aperture of the laser pointer onto
the object. It's harder to see clearly, but you can adjust that image
so that it is as sharp as possible. This works well enough for
close-focussing indoors, but isn't ideal elsewhere.
Finally, how to set infinity? Just shine the laser pointer in
through the front of the lens and put a piece of ground glass or paper
at the film plane. Focus until the spot at the film plane is as sharp
as possible. Often the pointer is too bright and scatter confuses the
issue. If you put a polariser on the front of the lens you can tune
the brightness of the beam by rotating either the filter or the
pointer.
*Don't* go looking into laser beams, especially the Class III
strength pointers.
Have fun.
Struan
[Ed. note: thanks to Michael Gudzinowicz for sharing these tips!..]
From: [email protected] (Michael Gudzinowicz)
Newsgroups: rec.photo.equipment.medium-format
Date: 19 Jul 2000
Subject: Re: Adjusting scale focus of an old folder
Tan
Tracing paper is hit or miss (about 1:99 odds).
They are quite accurate assuming no one has adjusted them, and the folder
standards have not been damaged or worn.
Occasionally, for moody portraits in low light. You don't need a soft
focus lens or filter with the lens at wide apertures. Corners are sharp @
f/16.
I posted these instructions for setting focusing scales some time ago:
Rwh56 [email protected] writes:
The following knife edge method which is used for accurate focusing on
stars can be used to check and set the infinity position of the Nettar.
If you open the camera back and check the film path, you will probably see
two inner rails upon which the film rests, and two outer rails which
contact the pressure plate. Cut a small sheet of plexiglass so that it can
rest on the two outer rails in the position of the pressure plate. In the
center of the plexi along the lens axis, glue an exposed/developed film
chip (black; emulsion up; _very_ thin superglue layer) which has an edge
that has been cut at an angle so the emulsion "overhangs" the plexi to
form a knife edge. (For medium format, add paper backing for 120 film.)
The plexi is placed on the film rails with the film/emulsion facing the
lens. A high power loupe is focused on the cut edge of the emulsion which
is in the position of film held by the pressure plate. The observer moves
their eye from side to side, and when the stars are in focus the image is
sharply cut by the knife edge. When not in focus, the knife cuts through
the "cone" of rays at some point from the apex, and the transition isn't
sharp.
You may not need to use the knife edge for routine focus adjustment.
Instead, a piece of plexiglass can be placed on the inner rails or frame
which contact the emulsion, and a loupe can be focused on the plexi
surface nearest the lens. Alternatively, ground glass may be used, or
glass or plexi with a coat of clear _matte_ wood sealer. The paper you've
tried does not have rigid tolerances.
Also, check focus on nearby objects at the distances and f/stops you'd
normally use to take photos (focus may shift as the lens is stopped down).
Another email reply which might clarify the method:
I forgot that I had ever posted this, but the method seems familiar.
If you don't develop your film and have backing paper lying
around, you can cut a small piece from the tapered edge of
the film leader, and put tape on the roll to keep it light
tight until you use it.
You can use either. The requirements are that the glue layers
are thin - Superglue seems to work if is kept away from the edge
where focus is tested (no beads/drops).
What you want to do is to cut the film with a razor blade or
matte cutter at a 45 degree angle to the emulsion. Then
the angled edge of emulsion surface hangs over the glass
where the film plane would be.
I've modified your diagram below.
You should use a high power loupe which you can focus on the
apex of knife edge of the film - focus is critical.
When the trees are in the same plane of focus, if you move your
eye from side to side, the position of the trees will not move relative
to the edge. If you were to use distant lights or stars (this method
is commonly used in astrophotography to set focus), then when you
view the image from different angles as above, the stars are sharply
cut off. If they are out of focus, the edge cuts through the cone
rather than the apex of the bundle of rays forming the image, so
the transistion isn't as sharp.
From: Struan Gray [email protected]
Robert Monaghan, [email protected] writes:
This is essentially the same as imaging the aperture of the laser
pointer: in both cases you create a pattern of light behind the lens
and then go looking for the conjugate point onto which it's focussed.
As you said, the problem is making sure the source image is at the
same place that the emulsion will be once you stop dicking about and
start taking photos. Michael Gudzinowicz has re-posted his knife-edge
jig for finding the focal plane which uses a dimensionally-stable
piece of plexiglass in contact with the pressure plate rails and a
real piece of film to set the emulsion position. Provided the film is
a nice dark black, the same setup would be good for back-illumination
with a light or laser pointer. Obviously you could use an exposed
piece of film with a pattern on it.
I would reiterate that looking into focussed lasers is not a good
idea, even with supposedly weak laser pointers. For instance, I don't
use these focussing schemes if the object is a person. It's a bit
like staring at the sun: everyone does it, especially kids who are
told not to, but the potential for damage is there. Paradoxically,
it's the cheapest laser pointers sold in markets and
everything-for-a-dollar stores which have the highest powers, since
they avoid or ignore product safety rules.
A collimator gives you light at infinity, as does a laser. The
collimator beam is wider, but you can always move the laser sideways
or use a beam expander. Collimated white light avoids problems like
sensitivity to scattered light being amplified by the laser's
coherence, but semiconductor lasers have such poor coherence that for
these sorts of applications the point is moot.
With all these things there is fairly significant practical jump
from 'good enough' to accurate. Astronomy lens hackers have the
advantage that even simple machine tools can keep everything
circularly symmetric and parallel. Cameras with movements, bent
scissor struts, or out-of-wack lens elements have a lot more degrees of
freedom, and to get precision results you really need to have some sort
of optical bench or rail. I have several, but have never bothered to
bolt a camera to any of them since I never do precision photography
like aerial surveying or astro work.
Struan
> This is all with an Agfa Isolette:
>
> I used the tracing paper method and focussed at a distant building. By and
> large it's a "best guess by eye". Now I am skeptical about my QC.
> Question is, how accurate are the scales which were calibrated by the
> factory anyway? Down to half a meter?
> Does anyone use their folders at apertures larger than f8?
> Thanks for any advice in advance.
>I acquired a Zeiss Nettar 6 X 9 folding roll film. It has a coated novar len
> It employs scale focusing. The front element rotates and the scale is mark
>along the rim of the lens ring. I wanted to check the accuracy of the scale
>In particular I wanted to check the infinity setting. So, I cut some tracin
>paper and taped it on the film plane. I tape one end to a spare spool and
>pulled the paper tight. I waited for the full moon to come out tried to foc
>it on the moon. But the moon is so darn small on the tracing paper that a
>large range of positions on the scale appeared equally in focus. Is there a
>better homegrown way to set the infinity? I aint buying a high falootin
>collimator. But I was wondering about turning my slr camera into a
>collimator. Any thoughts are appreciated in advance.
|____ Lens ____|
(The outer rails should be in contact
with the plexi. They are separated)
___ ___ in the accompanying diagram.)
|___| _____ |___| <- outer rails for pressure plate
\____| <- film chip (knife edge)
_____________|___|_______ <- paper from 120 film
^
focus loupe on the edge
at the plane of the emulsion
>Could you please help me use this method to set the focus on
>my 120 film camera.
>
>Clear glass in the shape of the pressure plate, got it.
>
>The paper I get from the roll film backing, I guess maybe peel
>it off? What thickness should this be if I can't peel it off?
>Section of film-- is this fully exposed negative film? do you
>want a black edge or a white edge to examine? If it's a white
>edge you don't care where the emulsion is on the test piece,
>just placing it where the emulsion will be, correct.
>I'd guess the that the layers in the camera are:
>
>---pressure plate---
>---paper backing----
>------film----------
>----emulsion--------
>
>---- lens ----------
-------------------------
| <---pressure plate or glass at PP position
-------------------------
| <---paper backing----
--------------
\ <------film----------
\ <----emulsion--------
-----------------
---- lens ----------
>so I want to cut the film at a to a knife edge, emulsion at
>the apex. Then I can focus on some trees a half mile away and
>examine the edge to look for very sharp lines on the edge with
>a loupe, is that right?
>> the film emulsion. A clear glass can be used, with a section of paper
>> glued to it, supporting a section of film which is cut on an angle so
>> the emulsion forms a knife edge. Focus is determined by using a loupe
>> to check for a sharp cutoff of the image when it is projected on the
>> knife edge.
Newsgroups: rec.photo.equipment.medium-format
Date: 20 Jul 2000
Subject: Re: Adjusting scale focus of an old folder
> I have heard folks use a slide of their favorite
> test chart, emulsion side to lens, and use that with
> a light source (slide projector?) thru the camera
> to project the crisp lines as another way to test
> the plane of focus
> I still like Tomosy's collimator project in his first
> repair book using binocular parts and mirrors.
> Worth setting up if you get serious?