jupiter-12 2.8/35mm lens
The Jupiter 12, 35mm f/2.8
lens is a popular and well-regarded Soviet lens, 
and was made in L39 (Leica) and Contax mounts. I bought mine for use with my Zorki-1 and FED-2 cameras, but it is compatible with a very large range of camera models,
not just the Soviet beasts.
It is derivative of the pre-World War II Zeiss
Biogon 35mm lens. The rear element of the lens bulges out like a delicate
meniscus, beautiful to behold, but is disconcerting if you don't happen
to have a rear cap for the lens. Fortunately, a film cannister, cut
down to about 3cm high, and built up around the inside circumference
with some duct tape, will make an excellent rear cap if yours has gone
AWOL like mine... assuming it ever did have a rear cap; I don't know
since mine was missing from the start.
I bought mine in Wroclaw,
Poland, and it appears to be in excellent condition. The serial number
indicates that it was manufactured in 1957, which makes the completely unblemished
rear element all the more remarkable.
The non-retrofocus design
of this lens means that the rear element very nearly touches the film
- an arrangement that ensures minimum image distortion - far less than
an SLR lens can achieve without some fancy optical footwork. Alas, it's
not a lens for everyone. It will not fit certain modern L39-mount or M-mount cameras such
as Leica CL/CLE or current Voigtlander Bessa L, R or R2 cameras, to mention
but a few (I suspect the same issue will apply to the Voigtlander Bessa R3 cameras, as well as the upcoming R4). Mostly, this is because of the in-built light meter sensor in those cameras. Most rangefinders of an earlier vintage should have no trouble with this lens.
A magnified view of the rear
element of the Jupiter-12.
Mounting the Leica-Screwmount Jupiter 12 on FED-2 Cameras
Even Soviet FED-2 cameras may need a little
adjustment to 
accommodate this lens, though this is easily & safely
accomplished by bending the rangefinder cam ever so slightly upwards.
I recently went through this exercise, upon receiving good advise on
how to proceed from the Russian
Camera User's Forum. The lens mounted without a problem on my Zorki-1,
but I just couldn't make it "bite" on the FED. If you find
that you cannot mount this lens on your FED-2, here's what you need
to do:
Find the rangefinder
cam at the top of the lens mount.
With a pair
of heavily padded pliers that open wide enough to span the distance,
place one jaw on the top of the camera and the other jaw on the cam
foot (shown above), and gently squeeze - ever so slightly. Try mounting
the lens; repeat if necessary. It usually only takes a millimetre or
fraction thereof. This will not affect rangefinder adjustment if done without aggression.
I was also advised
of an alternative fix, which is to remove the rangefinder arm and bend
a tiny "crimp" into it, so that it swings clear of the rear
of the Jupiter 12. This was a bit beyond the capabilities of my toolbox (or me!),
and the quick-and-dirty fix worked just fine for me anyway.
Sample Photographs
Other Lenses: Industar-22 Industar-26 Jupiter-9
