Homebrew Short-Focus Lens Mount Converter
Can I use my old lenses on a new or different brand of camera?
This
FAQ will try to answer that question.
Here is a short table of available converters from one source (Cambridge
Camera Exchange 212-675-8600) as discussed in a great article in July 1994
Popular Photography by Mr. Herbert Keppler in his SLR
Column. For an overall discussion on lens mount converters and issues,
I highly recommend this article.
However, I can not recommend Cambridge Camera
Exchange
based on their past negative Better Business Bureau
record of problems reported by buyers. Similar adapters should be
available from other sources; but if you elect to deal with CCC, please
review this report and user dealer
reviews on our "buyer beware" pages and be fore-warned.
Fortunately, I can recommend B&H Photo-Video from personal
experience and many positive postings by other buyers. They have a number
of commonly requested optical lens mount adapters available.
Our Impact! used gear dealer links has
numerous potential sources for lens mount adapters, both new and used. For
used sources, see KEH which has
extensive used gear listings including many adapters. Finally, most
mailing lists by brand (e.g., see Egroups listings) of photo gear can
suggest sources for specific adapters for their brand of camera (e.g.,
Minolta, Nikon, Canon..).
See Effects of Optical Converters on Sharpness
below:
Is it Worthwhile to Buy a Mechanical or Optical Mount Adapter?
T-mount converters to sundry lens mounts
(examples include Canon AF and Minolta AF bodies)
T-mount lenses range from fisheyes to long telephotos, and include other
items such as bellows and slide duplicators. The T-mount lens simply
screws into a T-mount adapter which mates to the desired camera
bayonet mount as if it were a bayonet mount lens. But the T-mount doesn't
provide for auto-diaphragm operation, due to the lack of coupling levers. So
you must use
stop-down metering and exposure or aperture priority automation modes
due to the lack of lens setting information connectivity.
Tamron's President Takeyuki Arai invented the original T-mount in 1959. There are at least two versions, one a solid fixed mount (T) and the other with three small screws (T2). You can loosen these screws and rotate the inner ring until the lens aperture ring and controls are facing upward and then tighten into place.
The Pentax Universal M42 Screw-thread mount used a 42mm x 1mm metric thread for its lens mounts. Tamron altered this mount slightly to a 42mm x 0.75mm pitch thread. Be careful that you don't try to force these very similar appearing mounts together! They may start turning, but will bind if you turn hard enough, possibly damaging the camera mount (M42) or lens (T or T-2 threads). Watch out!
Besides the thread pitch, Tamron also used a very long lens registration distance of 55mm. That means the lens mount was 55mm from the film plane. By comparison, Nikon uses 46.5mm. All the popular 35mm SLR camera mounts were shorter than 55mm. This carefully planned optical trick meant that T-mount lenses could be easily adapted to all the popular 35mm SLR mounts by simply varying the width and bayonet mount of the mechanical adapter. Clever!
The T-mount continues to be widely used today for mirror lenses, which have fixed apertures and therefore no need for automatic diaphragm operation. Slide duplicators and bellows are also often T-mount devices. Some weird 8mm and 12mm fisheyes were also made in a T-mount lens! And many preset telephoto lenses use T-mounts to save costs or simplify designs. Many of these lenses are now cult classics!
Incidentally, there is also a reverse T-mount adapter which lets you convert your bayonet mount lenses (e.g., Nikon) into a T-mount thread. This trick is most useful for macrophotography, since infinity focusing is usually lost. You can mount the lens-reverse T-mount combo in a T-mount adapter for another camera mount. The resulting adapters act like a short extension tube, and automation is obviously lost too. But such switcheroos may let you share one macro lens or bellows between different camera brands for the low cost of a few adapters.
Tamron also developed a later series of automatic diaphragm mounts. So far as I know, the T-3 mount lenses were never marketed. The T-4 system provided automatic diaphragm operation along with a manual diaphragm option. Recall that many lenses from the 1960s and 1970s were not automatic operation, but rather preset or even manual lenses. Vivitar adopted the Tamron T-4 system for their interchangeable lens mount lenses. In concert with Soligor, they jointly promoted a very similar TX mount.
The T-4 mounts were popular with camera store dealers who only had to stock a few lenses and some T-4 mounts to cover a huge number of potential camera models with automatic diaphragm operation lenses. The TX system overcame some problems with T-4 mounts on Konica Autoreflex using auto exposure and Canon, Pentax F and ES cameras with full aperture metering. Minolta users were also annoyed that aperture scales weren't in the right place to be seen in the viewfinder. TX adapters were also made for newer cameras such as Olympus OM-1/2, Mamiya DSX and MSX, Fujica ST801/901, and Rollei SL35.
The TX adapters are not recommended for use and generally not usable on the older T-4 series lenses. The T-4 series adapters usually are usable on the newer TX lenses. In some cases, a T-4 adapter will be quirky on a TX lens. For example, the TX lenses provide a maximum aperture at the center setting, stopping down if turned to the left or to the right. For Canon and Leica owners, the right side scale is used. For Nikon and most others, the left hand settings and scale are used.
The older T-4 adapters won't prevent you from using the Canon side with a Nikon or other lens. So what? Older Nikons such as my Nikon F2 and Nikkormats require you to set the maximum aperture by rotating the lens to the maximum aperture point. With a T-4 adapter on a TX lens, you can easily fool the aperture setting mechanism by going to far over onto the Canon aperture setting side. Your Nikon thinks you have a lens that is a lot faster than it really is, and problems develop from there.
The Minolta TX adapter has a lens aperture scale you have to setup to get proper viewfinder aperture readings. Usually, you have to set a U-shaped prong on the lens to match and take a pin on the adapter when you couple the adapter and lens together. There are various arrows and colored dots on the mounts to help make this easier. The T-4 lens end is simpler than the TX lenses, which have extra couplings and longer grooves for aperture couplings.
The early TX mounts had various color codes on them for Nikon users (orange at f/5.6) and other mount alignments. The later TX mounts just put an arrow on the lens mount and adapter. You lined up the respective pins and U-shaped slots to these arrows or dots, and just press them together. If you are using a shutter priority camera, check out the adapter instructions for correct lens setting for proper mounting.
Soligor also developed a T-5 lens mount with Tamron, and then a new Universal System (U/S, T/S, and C/S overseas). A few other interchangeable lens mounts were also offered, such as Chinon's varifit mounts and Komura's interchangeable lens mounts and adapter system. Relatively few such mount lenses and even fewer camera brand mount adapters were made available.
Only Tamron continued to develop and persevere with interchangeable lens mounts. Their ultimate goal was to develop a mount that would provide full automation on a wide range of 35mm cameras, simply by changing out the mount. An intermediate stage mount know as the Tamron adaptamatic was developed.
This mount used a long pin which had to be carefully inserted into the guts of the lens to link up with the automatic diaphragm mechanism. This mount proved somewhat flakey in practice, and subject to contamination by dust and sand in frequent use. A simpler and better solution was needed!
Tamron finally succeeded with their Tamron Adaptall and Adaptall-2 series
mounts. These mounts continue to be popular today, providing a number
of features including easy and simple interchanging between lenses
and mounts. Unfortunately, the new age of autofocus lenses has
generated a new Tower of Babel, variegated autofocus mount
electronics, and even software incompatibilities due to embedded
microprocessor chips in the cameras and lenses!
Regarding the M42 or Pentax/Praktica universal screw mount (42mm x 1mm),
there are several versions here too. A single diaphragm control pin type
mount will work with virtually all universal screw mount bodies for
stopped down metering. For full aperture exposures, a
second pin or lever was added to convey f/stop settings to the camera body.
But different bodies used pins and levers for this function, and the
location of the pin or lever differed in some models. The depth of travel
of the lever or pin also varied. So you can't assume these dual action
mounts will work with full aperture metering properly on all bodies. But
you can usually still do stop-down metering with any such lens on most
M42 mount bodies.
Besides Pentax and Praktica, M42 screw mount cameras included cameras by:
Tamron developed the T-4 adapter series in concert with Vivitar. The later Vivitar TX series automatic mount adapters were jointly popularized by both Vivitar and Soligor in a relatively larger number of mounts and lenses. Not to be outdone, Soligor got its own T-5 mount.
These mounts can be a little harder to use than a T-mount, since you have to align a coupling pin in the mount with the lens to provide auto-diaphragm operation. Frequently swapping out mounts could lead to errors and problems.
 |  |
| Vivitar TX Adapter (for Yashica) | TX mount Adapter on Lens (Nikon) |
| YS Mount Experience |
|---|
| The YS mount uses a small pin to actuate the stopping down of the lens. A control ring on the lens provides automatic or manual options. On my Sigma 18mm f3.5 in a Spiratone YS mount for Nikon, a mechanism converts the horizontal action of the nikon stop-down lever on the lens mount into a vertical push against the YS stop-down pin. On my newly arrived YS mounted lens, the alignment was off, so only manual operation was possible. Simply loosening three screws on the mount, and rotating to match another nikkor lens positioning, was all it took to fix this lens. |
The Y-S interchangeable mount system was a response to Tamron's first interchangeable mount systems of 1964 (T-4). The Y in Y-S mounts is after Mr. Yamaki, who was president of Sigma (hence, Y-S). Besides Sigma, Sun Optical Corp. also used these Y-S lens mounts on some of their lenses.
Soligor Mounts
Soligor jointly marketed T-4 lenses along with Vivitar (often sourcing their T-4 mount lenses under the Vivitar brand name, we're told). Tamron was a mainstay in developing these interchangeable mount technologies, as well as providing some lens offerings of its own. While Vivitar developed the TX mount, Soligor came up with their own T-5 interchangeable mounts.
After this, Soligor developed a Universal System series of mounts using a variety of labels (e.g., U/S, T/S, I/S in USA, C/S overseas...). At least six mounts were available, including Canon, Contax/Yashica, Minolta, Pentax, Nikon, and Olympus. The mounts outnumbered the original zoom lenses by two to one (i.e., 35-70mm f/3.5-4.5, 28-80mm f/3.3-4.5, 80-200mm f/3.8). These T-5 and U/S series mounts are relatively rare.
Chinon's varifit mounts are even rarer. Komura made a number of telephoto lens heads with interchangeable mounts (e.g., Bronica). Novoflex followed a similar pattern, with their own follow-focus and bellows mount lenses. See cult classic lenses for more on the Novoflex series.
If you have a lens in one of these rarer lens mounts, enjoy it. Unless you want to invest a lot of effort into locating older optics from the 1960s and 1970s, you should focus on more modern lenses and the only currently popular automatic diaphragm interchangeable lens mounts, the Tamron adaptall/2 series.
You will also find plenty of T-mount mirrors and bellows and related optics for sale. A modest number of T-4 and TX lenses can also be found with some effort, often at surprisingly low costs. If you have several brands of older cameras and mounts, you may want to invest in lens mounts that are compatible. This approach will open a way to share lenses cheaply and easily between your various lens mounts.
Medium Format adapters:
Because of the greater distance from lens mount to film plane in the
medium format cameras, it is usually possible to mount their lenses onto
35mm cameras. Unfortunately, the reverse is usually not true except for
macro photography use or for short mount lenses.
Example: a Hasselblad lens to Nikon body mount adapter
(circa $125 used!). Unfortunately, I found you also have to use a
nikon mount bellows or extension tube to provide the range of focusing
needed to use
the Hasselblad optics at infinity. Why? Because the adapter is only a
thin machined piece, while the lens needs to be about another 35mm
from the camera body to focus at infinity!
The photo below shows how a Pentax 6x7 camera user can use
their lenses on a Pentax K-mount camera body.
Reportedly, a Pentax 67 to nikon body mount adapter also exists. As you
can see, it is also quite thick. See below for more details on medium format
options.
Non-autofocus lenses on Autofocus Mounts
Whether you can use a non-autofocus lens on your autofocus mount camera
has to be determined on not only a camera brand basis, but even the
specific model.
While Nikon has a reputation for its users's ability to use old lenses on
new mounts, and vice versa, the truth is more muddled. For example, a
Nikon EM might be damaged if you attempt to mount an older pre-AI lens
with meter coupling prong. The same is true of many of the newer autofocus
Nikon cameras. Usually it is only the professional Nikons such as the
F3 that provide the broadest range of lens usability, while the
amateur models limit you to the latest autofocus lenses. Here again,
adapters may be available that will permit mounting sundry lenses, but
at the obvious loss of autofocus operations
A few notable exceptions exist to the above point, in that certain
earlier autofocus lenses had the autofocus motors and electronics built
into the lens, rather than into the camera and lens-mount. So you may
retain autofocus operation with these lenses, even when mounted on a
different model camera model. While more bulky, these lenses are the only
way to get autofocus operation on older Nikon all-mechanical models, for
example. (see auto-AF lens
list)
Unfortunately, autofocus lenses usually take bigger optical and
mechanical mounts to provide functionality than the older mounting
schemes allowed. This changeover obsoleted many older lens lines
(e.g., Canon FD), while other mount changes precluding using some
brands of older lenses on the new autofocus mounts.
Even the autofocus
mounts are themselves changing more rapidly on many brands, bringing
more features, but at the price of limited functionality or early
obsolescence of earlier autofocus lenses. Again, there are exceptions,
such as using a Nikon 35
f/2 AF autofocus lens which can physically mount on the original Nikon F.
But autofocus operation is
obviously lost, and stopped down metering has to be
used due to the lack of a metering prong.
Unfortunately, when mounting lenses on 35mm SLR cameras, we don't have
such huge differences or leeway in our adapters. But it may be possible
to provide such direct mechanical mount adapters if the distances permit.
More expensive mounting adapters may provide some or all automation
functions, but these are rare and much more costly (e.g. up to $200 per
adapter). But that's cheap if it lets you use an expensive fast telephoto
lens that cost $3,000+ instead of selling it at a loss.
Where the distances are longer on the camera body than on
the lens, you have to revert to optically based adapters (see list
and discussion above). For example, a Nikon body (46.5mm lens
registration) needs an optical adapter if you intend to use a minolta
MD lens (43.5 mm). In this case, the Nikon body acts as a 3mm
extension tube, so the Minolta lens can't focus at infinity without an
optical element in the adapter.
Be aware that various versions of adaptall mounts were developed, and
make sure your purchase will work with your adapters if purchased
separately. My own experience with a vivitar 21mm adaptall mount was very
positive. I easily converted to the nikon AI mount simply by trading
out adapters. For $20, I also bought a used adaptall mount for my minolta
camera, enabling me to use the 21mm lens in an underwater housing. The
same adapter can be used to borrow my 300mm vivitar adaptall lens from Nikon
use
to Minolta camera body use. My own preference is to use the less expensive
third party
lenses in the very wide and long telephoto range. In these extreme ranges,
infrequent
use would make it very hard to justify the cost of a prime original
manufacturer's lens.
If you find a good buy on a given lens in the wrong mount,
you can buy it and use it with an adapter you can buy separately (circa
$20-30 used). If you use a number of camera brands, you can share one lens
between all of them by using different mounts. Once you have one lens and
an adapter for each of your camera bodies, each adaptall lens you buy is
like buying a lens for each of your cameras.
The following listing is not a complete listing of all Tamron adaptall
mounts (see Tamron website). But it
highlights many of the more interesting manual camera mounts which are
available, including some rare mounts like Rollei and Leica. Why these
adapters are so nifty is the ability to use affordable Tamron adaptall
mount lenses of relatively recent design and quality - including zooms,
APO telephotos, and ultrawide manual focus lenses. So you can enjoy
relatively affordable Tamron lenses on older or more expensive
(Leica..) bodies for which no equivalent current (or affordable) lenses
are available. Even better, you can share such lenses between these older
and even collectible manual cameras and more recent models (including some
autofocus designs, albeit in manual mode, such as the Pentax KA mounts).
Listing of Manual Camera Adaptall Mounts:
Nikon AI-E (no "ears") Nikon AI Canon FD Pentax KA Olympus OM Fujica ST Rollei 35mm Pentax ES Leica R4 Minolta MD Praktica Konica AR Praktica B200 Ricoh XR-P[Source: SLR, H. Keppler, p. 18, March 1997, Popular Photography
The problem with
rangefinder cameras motivating use of the short-mount lenses related to
the lack of a reflex mirror to look through the taking lens. Both for
closeup and telephoto users, this lack was a severe problem. The partial
solution was to use short-mount lenses which mated to a reflex or viewing
mirror (and often prism) attachment that in turn plugged into the camera.
Now the user could see what the telephoto or closeup lens was seeing.
Unfortunately, many short-focus lenses were for early Nikon and Leica
rangefinder cameras, such as the Nikon lens example featured in a Bronica
mount at the top of this article. I say unfortunately, because the price
of such lenses is very high due to collector interest in many cases. The
benefits of such short-mount lenses is that they offer very high optical
quality (Nikon, Leitz, Telyt..) in a lens that is easily adapted for use
on a variety of 35mm and medium format cameras. If a bellows focusing
unit is provided with the lens, then you may just need a bellows mounting
adapter (T-mount..) to use these lenses on a wide variety of cameras.
However, you can use many 35mm macro lenses on medium format cameras with
the right lens mount adapters, as shown by the Nikon micronikkor mounted
on a Bronica 6x6 shown below. This works because the extra length of the
medium format body acts as an extension tube for the 35mm lenses. While
that makes infinity focusing impossible, it does make for a flat field
macro lens setup. Note that 35mm lenses when used in such closeup setups
are capable of covering 6x6 and larger formats, depending on the degree
of magnification and extensions used.
A second problem relates to adapting lenses between medium format
cameras. Only a relative handful of adapters are available, and these are
usually limited to focal plane cameras. Leaf shutter users are locked
into their lens mounts due to the complexity of lens automation and
coupling.
Fortunately, there are some exceptions, especially for focal plane
shutter users. Lenses for Kalimar 660 medium format cameras could also be
used with an adapter on Bronica S2/EC forcal plane cameras among others.
Similar adapters were made by Ercona corp. (Astro-..), Stirling and
Howard (Astrogon..), Kling Photo (Kilfit), Zoomar, Birns and Sawyer,
Novoflex, Burleigh Brooks, and even Komura and Vivitar (see Bronica Consolidated Lens listings for details).
Many lenses can be adapted to focal plane medium format camera use.
See Bronica home brew lenses page for many
examples and details. Some manufacturers such as Kalimar's Kiev 88 lenses can
also be adapted with factory provided mounts. Kalimar also make other
optical items such as prisms that fit Hasselblads.
For professionals who already own Hasselblad lenses, there is an adapter
to mount and use these lenses and accessories (bellows, tubes) on the
35mm Nikon cameras. The photo at the top of this article shows the same
approach in an adapter for owners of both Pentax 6x7 cameras and Pentax
K-mount 35mm cameras. Finally, for $35US you can buy from Kalimar
an adapter to use
the entire line of Kiev 88/Pentacon 6 medium format lenses on your Nikon
or Pentax M42 screw thread mounts.
Finally, some lens mount adapters are currently being made for medium
format focal plane camera users by Cambridge Camera Exchange. They are
offering a 500mm f/8 telephoto in Hasselblad focal plane camera mounts,
pentax and mamiya 6x4.5 focal plane camera model mounts, Kiev/Pentacon 6
mounts, and others. The cost is only $399.95, or less than a tenth of
some OEM manufacturer's lenses, albeit for a preset lens. But the 35mm
buyer gets an even better bargain, as the same lens is available as a
T-mount preset lens for only $99 new.
As noted above, you will probably lose autofocus features, especially
since they aren't present on most earlier lenses, but also between models
(e.g., Nikon AF lenses won't work in AF mode on Canon). You will probably
have to use manual focus and stop-down metering, and close down the
aperture manually. But you might be able to use both stop down metering
and aperture priority metering on cameras with aperture priority
options.
Optical Lens Adapters - fisheye, wide angle, and telephotos:
A related idea for sharing optics between different mounts was developed
decades ago for mounting optical converters on the front of the normal
camera lens. Many of these optical converters use series filter mounts,
which were a standard size mount (e.g., series VIII corresponds to 67mm
filter when threaded adapter is used). With one adapter ring, you could
use an entire lineup of series VII filters on your nikon, for example. Or
you could use the same adapter ring to mount some unusual optical
converters including a handy and fun 180 degree circular fisheye converter.
For circa $50, you can buy a front of the lens screw-in fisheye adapter
that will enable you to get a 180 degree fisheye effect with your normal
lens. Naturally, these adapters lack some of the snap in contrast and
flare resistance of prime fisheye lenses, as well as exhibiting more
pronounced light falloff and other defects. But their cost is only a few
cents on the dollar of the cost of a prime fisheye lens, and they can be
every bit as much fun to use. You can also buy a wide angle adapter thar
provides a 21mm (.42x times 50mm normal lens) view at a cost of $30 up. A
less useful telephoto adapter also converts your normal lens into a mild
telephoto (circa 75mm).
This camera body "surgery" approach really makes sense only if you are a
pro with such a major investment in expensive pro glass that you simply
can't justify the cost of selling out and buying anew. For example, a
pro doing macrophotography using flash might have needed TTL flash
exposure control when it was a new development, not available on his
usual camera brand. Adapting a new body to provide this function with
his or her existing pro lenses could have been an interim solution
until the feature became more widely available in their preferred
camera brand cameras.
In a few brands - Nikon and Pentax chiefly - you can use autofocus lenses
on earlier pre-AF bodies with full auto-diaphragm action and features.
You may be able to use certain pre-AF and manual focus lenses on some of
the AF bodies too. But beware, for example, of using pre-AI nikkors on
AI/AF only bodies, as the older lenses can damage the newer bodies if
mounted.
Even if you can mount pre-AF or manual lenses on AF bodies, you often
can't use them in autofocus mode, and often can't use them with even
stop-down metering which is a feature lacking on some lower-end AF models.
This brain-dead approach is a giant leap backward as far as lens mount
conversion goes. Don't forget this limits use of T-mount mirror lenses,
telescopes and microscopes, and other areas of photography. So if you are
wedded to an autofocus camera system, expect some major limitations on
what kind of lens mount conversions and interchanges you can do.
You can also do this conversion process backwards. For example, I am
looking for the T mount version of the 7mm f5.6 spiratone fisheye and
12mm f/8 sigma T-mount fisheye lens. For under $150, I could use these
lenses on any camera that can take a T-mount (i.e., nearly all of them).
I already have and share T-mount bellows and slide duplicators and
several long telephoto lenses in T-mounts. If and when I find these
lenses, I will buy them and use them on whatever bodies I happen to be
using at the time.
Another backwards example is buying a pentax M42 screw mount to Nikon
mechanical adapter (used). Now I can mount my Pentax SMC super takumar
200mm f3.5 on my Nikon bodies. At this point, I can start buying any odd
but inexpensive telephoto, wide-angle, or specialty lenses from the forty
odd brands of lenses made for the M42 screw mount cameras. I can also use
sundry telescope and microscope and other specialty items with this
adapter too. Since screw mount lenses are in disfavor, the prices are
often very cheap.
Another backwards reason to use adapters is the too-common experience of
having your main camera and lenses stolen. You might have a number of
lenses for the older camera still on hand at home, but be unwilling to
be tied down to that brand now that your main investment has been stolen.
You can decide to switch brands, but not want to immediately replace all
of your lenses. This case would be a good time to consider the converter
mount options.
Another backwards reason might be the relatively low resale value of your
older lenses versus the much higher purchase price of your new lens
system. For infrequently used but very expensive wide angle and telephoto
lenses, as well as specialty lenses (e.g., macro), you may be content to
keep both your golden oldies and the real gold they will save you in lens
costs.
But perhaps the best reason to become aware of these adapter options is
the chance to buy a recent automated camera body with perhaps an
autofocus zoom lens or two and play with it. Before learning about these
options, I wouldn't have dared start a second line of cameras, given the
investment I already have in my nikkor lenses. But now I can use those
lenses on my new brand-x body, without having to buy a new set of
telephoto, wide angle, and specialty (macro) lenses.
In summary, you can often mount and use a much wider variety of optics on
your camera body than the original maker would want you to know about.
Doing so can save you lots of money, provide unusual optical effects
inexpensively (e.g., fisheye adapter), or let you try out a new camera
body or brand without abandoning your considerable investment in another
system. Finally, you can build your own adapters and use any number of
lenses in inventive ways, such as macrophotography. In the process, you
will learn a lot more about cameras and lenses and photography than the
person who never experiments and loses out on all this fun.
| OEM Lens Mount Converters |
|---|
| Photos courtesy of Chung Wong |
 Canon Converter N - Nikon AI lens to FD body |
 Canon Converter E - Exakta lens to FD body |
 Canon Converter P - Pentax Screw lens to FD body |
 Minolta Adapter P - Pentax Screw lens to Minolta MC/MD body |
 Konica Exakta adapter II - Exakta lens to Konica AR body |
What Fits My CameraModern Photography magazine, since absorbed into Popular Photography magazine, used to publish annual lens listings with a section titled What Fits What???. The material below is abstracted from the Feb. 1980 issue, and related to lenses and cameras of that period.
Since many people now buying such classic cameras don't know all of their lens options, this may be helpful information. You should also check web sites devoted to specific cameras (see camera sites for useful links...).
| Effects of Optical Adapters on Sharpness | ||||
|---|---|---|---|---|
| Vivitar 28-85/f3.5-4.5 at 28mm | ||||
| f/stop | center | lpmm | corner | lpmm |
| 3.5 | exc | 60 | exc | 47 |
| 4 | exc | 67 | exc | 47 |
| 5.6 | exc | 75 | exc | 53 |
| 8 | exc | 75 | exc | 60 |
| 11 | exc | 67 | exc | 53 |
| 16 | exc | 67 | exc | 53 |
| Vivitar 28-85/f3.5-4.5 at 85mm | ||||
| 4.5 | exc | 57 | exc | 51 |
| 5.6 | exc | 64 | exc | 51 |
| 8 | exc | 72 | exc | 57 |
| 11 | exc | 72 | exc | 51 |
| 16 | exc | 64 | exc | 51 |
| Vivitar 28-85mm f/3.5-4.5 + optical adapter (36-101mm f/5-6.3 at 36mm | ||||
| 5 | exc | 58 | exc | 46 |
| 5.6 | exc | 65 | exc | 52 |
| 8 | exc | 73 | exc | 52 |
| 11 | exc | 73 | exc | 58 |
| 16 | exc | 73 | exc | 58 |
| 22 | exc | 65 | exc | 52 |
| Vivitar 28-85mm f/3.5-4.5 + optical adapter (36-101mm f/5-6.3 at 101mm | ||||
| 6.3 | exc | 51 | exc | 40 |
| 8 | exc | 57 | exc | 45 |
| 11 | very good | 57 | exc | 45 |
| 16 | exc | 57 | exc | 51 |
| 22 | very good | 51 | exc | 45 |
Surprise! Mr. Keppler's test results support his conclusions that these
optical converters/adapters have only a very modest impact on quality.
These optical adapters are actually weak negative lenses which act as
modest teleconverters. The weak teleconverter effect explains the shift from
28-85mm to 36-101mm shown in the lower test results.
The change in focal length of circa 23% was accompanied by a loss of
light of about a stop. Again, that's why Mr. Keppler shows the f/3.5-4.5
range was converted to a f/5 to f/6.3 range using the optical adapter.
So let's see. For $30 street price, this adapter would allow you to use
lenses such as minolta MD lenses on a Maxxum body, as one example. You do
lose auto-diaphragm operation, and have to use stop down metering. But
the impact of the optical element in the optical converters on quality is
very minor, as these results suggest.
In short, these interesting tests help confirm how minor the effect of
optical converters are on sharpness and resolution overall.
Can someone help me out with an explanation of what the various T (T,
T2, etc.) mounts are & how they differ from m42?
The various T mount systems are interchangeable mounts that allow specific
T-mount lenses to be used on a variety of cameras. For example, if you
bought a T-mount bellows, you could use it on a Minolta AF camera by buying
a Minolta AF T-mount and attaching it to the bellows; if you have a Nikon
you'd buy a Nikon T-mount, etc.
The generic "T" mount is a simple screw mount that doesn't include any form
of autodiaphragm, aperture coupling, etc. -- it's just used for purely
manual-aperture devices such as bellows, close-up equipment (e.g. slide
copiers), cheapo mirror lenses, etc. Although this is a screw-type mount,
it's completely different in size than the M42 mount. This mount (also
called the Praktica/Pentax screw mount, since it was used on those brands
of cameras) is a direct mount that can be used only for mounting M42
lenses
on a camera with an M42 mount; it's not an interchangeable mount like the T
system.
T2, T4 etc. were other forms of interchangeable mounts used by some
third-party lens manufacturers (Soligor, Vivitar, etc.) to provide an
interchangeable mount system with autodiaphragm and aperture coupling.
These interchangeable-mount lenses were once fairly popular when SLRs had
fairly simple lens mounts -- they let dealers stock a smaller inventory of
lenses, and then when you wanted, say, a 135/2.8 for your Canon, they just
sold you a T-something lens and the appropriate adapter for your camera. As
camera mounts got more complex, with more couplings and so on, it became
harder to engineer interchangeable mounts for all of them, and these lenses
became less popular.
I'm assuming that the C-mount adapters I see advertised are 'Contax'
mount - is this correct?
Probably not. The C mount is a standardized screw mount used on many 16mm
movie cameras and video cameras. A C mount adapter could either be an
adapter to mount a "generic" device on a C-mount film/video camera, or to
adapt a specific mount of 35mm camera lens for use on a film/video
camera.
Fortunately, you can still meter using the stopped-down metering approach
on most cameras. By pressing a depth-of-field button, the camera is
placed into stopped-down metering mode too. The lens is stopped down to
the taking aperture automatically on some adapters. On T-mount and other
purely mechanical mounts, you may have to turn the aperture ring to the
desired taking aperture. In either case, the camera is now metering at
the actual stopped down aperture. You can set the shutter speed and
aperture as desired, based on your meter reading.
If this sounds funky, remember that the early ground breaking SLRs such
as my Pentax used this technique all the time! When taking photographs in
daylight, you may have to only meter the infrequent tricky lighting
situation. You can also use a handheld meter or spotmeter if available.
On aperture priority cameras such as the Nikon FE or F3, you just set the
aperture and the camera determines the shutter speed automatically at the
instant of exposure. I would recommend an aperture priority camera for
anyone wanting to use a number of pre-set and T-mount adapter lenses.
If you intend to do photomicrography with T-mount
bellows, then look for an auto-aperture camera with thru-the-lens
flash control of exposure. Your camera can then compute the correct
flash exposure automatically for you when using bellows or extension
tubes.
Shutter priority systems or program exposure modes
generally require you to perform stop-down metering with the
non-automatic coupled adapters (such as the T and T2 mounting adapters).
In a program exposure mode camera, the camera follows a set of programmed
rules to adjust shutter speed to some minimal setting (e.g., 1/60th)
after which it increases aperture to provide the needed light levels.
Since mechanical mounts without aperture coupling can't perform the
latter task, they don't work well in program mode for many situations.
A series of semi-automatic bellows, such as those by Novoflex and other
brands, makes it possible to perform some common automatic operations. An
example would be stopping down the remote lens mounted at the end of the
bellows. But the semi-automatic bellows won't convey lens settings back
to the camera, as a mounted lens would, so stop down
metering is usually employed.
The least expensive and most interchangeable bellows use simple physical
mount adapters to mount your lenses onto the bellows, and the bellows
onto your camera. A T-mount adapter at the end of the bellows is used to
mate the bellows to the camera lens mount.
Reverse T and T2 mount adapters are available for many camera brands - see
Willem-Jan
Markerink's registration mount page for details (at bottom).
T2 is a distinction of the generic T-mount.
T2 does not offer any coupling, T4 does.
T2 is M42x0.75mm pitch, whereas Pentax/Praktica screwmount is M42x1mm
pitch....and there is 10mm difference between the registers....not
interchangeable at all!
For more technical data see the chapter on camera/lens registers on my
homepage:
http://www.a1.nl/phomepag/markerink/mainpage.htm
From http://www.srbfilm.co.uk/index1.html - SRB Catalog - p.17/18 12/2002 (prices obviously subject to change - just for your information/interest... Lots of C mount to 35mm adapters ($39.95 etc.) optical elements used in adapter: Canon FD lens to Canon EOS body - $40.42 Minolta MD lens to Minolta AF body - $50.85 M42 lens to Nikon body - $31.89 M42 lens to Olympus OM - $59.08 Canon EX1/2 video to 35mm lens mounts $89.95 Canon XL1 video to 35mm lens mounts $129.95 Canon FD to Nikon lens $69.95 Exakta (replacement flange) to M42 lens $29.95 M39 Leica/zorki to various 35mm $59.95 various 35mm to Leica visoflex lens - ask for quote various 35mm to pentacon 6 lens - ask for quote Mamiya 645 body to pentacon 6 lens - $99.95 Non-optical mechanical adapters: canon EOS to M42 lens - $24.75 Canon FD to M42 lens - $15.96 Contax/Yashica to M42 lens - $12.01 Leica M Bayonet to Leica M39 (28-90) - $52.24 " (50-75) - $52.24 " (35-135) - $52.24 M39 leica or zorki body to M42 lens - $14.95 minolta MD to m42 lens - $13.25 Minolta AF to M42 lens - $23.95 Miranda M44 to M42 lens - $14.95 Pentax K to M42 lens - $13.98 Praktica B to M42 lens - $21.78
you wrote:
>Pentax K to Canon FD body >Pentax K to Nikon body >Canon non-AF lens to Nikon body >Canon FD lens to Nikon body
The two above are identical and we have this. It's our product
code GBCANC
>Minolta AF lens to Nikon body >Minolta MC/MD lens to Canon FD body >Minolta MC/MD lens to Nikon body >Olympus lens to Nikon body >Yashica Contax lens to Nikon body >Nikon lens to Canon AF body
We have this. It's our GBCACAFN
>Canon FD lens to Canon AF body
We have this. It's our GBCACAFC
>Minolta AF lens to Minolta MC/MD body >Minolta AF lens to Pentax K body >Pentax K lens to Minolta AF body
We have this. It's our GBCAMAFP
Regarding the others -- our buyer for this genre believes (and I tend to
concur) that CCC's claim that they can provide them will not be borne out.
He suggests you try to obtain some and let us know your success.
--
regards,
Henry Posner
Director of Sales and Training
B&H Photo-Video, and Pro-Audio Inc.
http://www.bhphotovideo.com
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on lens mounts and adapters (this split greatly speeds up downloading this page)...