35mm Jupiter 12 Question

[EPPaar]

I recently purchased a Jupiter-12 35mm lens to use with my Contax IIa and Kiev 4a. I would have preferred a Zeiss, but today's prices makes that unrealistic. I am worried about the rear projection of the Jupiter. It does clear the shutter on the Kiev, but I am not sure about the Contax. Does anyone know if the Jupiter-12 35mm is safe to use on the Contax?

Thanks for any advice.

Peter in Savannah

 

[xayraa33]

The J-12's rear glass will hit the shutter on the Contax IIa....that lens will be fine on the Kiev or a pre war Contax II or III and it will even fit on the Nikon RF cameras if you don't mind putting a big scratch in the front face plate from mounting the lens. ( ask me how I know 🙁 )

 

[EPPaar]

Thanks for the information. I was afraid that I wouldn't be able to use it on the Contax. I'll have to be satisfied with the Kiev.

I won't ask about your problems with the Nikon - I hate to see grownups cry!

Peter from Savannah

 

[Cascadilla]

Nikon RF lenses also fit a Contax IIa--you should be able to find a Nikkor 35 mm f/2.5 for less than a post war 35 mm Biogon and it is a good lens.

 

[EPPaar]

Thanks for the tip. The prices of all 35's, regardless of brand, seem to have risen dramatically in the last year. I didn't realize that the Nikon RF's used the Contax mount.

Peter in Savannah

 

[newst]

Thanks for the tip. The prices of all 35's, regardless of brand, seem to have risen dramatically in the last year. I didn't realize that the Nikon RF's used the Contax mount.

Peter in Savannah

Nikon made rangefinder lenses for three different mounts, LTM, Contax, and their own mount that was supposed to be a direct copy of the Contax, but ended up with a slight difference. When discovered Nikon started making lenses that exactly matched the Contax mount. These lenses were labeled Nikkor-C (the lenses for their own mount became Nikkor-S).

 

[Cascadilla]

For wide angle lenses the difference in the mount isn't that important. For longer lenses it is--I have both a 10.5 cm f/2.5 Nikkor and 13.5 cm f/3.5 Nikkor with the C on the barrel and focusing is quite accurate with my Contax bodies. For my 28 mm and 35 mm Nikkors, they are not marked with the C on the barrel and focus is likewise accurate.

 

[newst]

For wide angle lenses the difference in the mount isn't that important. For longer lenses it is--I have both a 10.5 cm f/2.5 Nikkor and 13.5 cm f/3.5 Nikkor with the C on the barrel and focusing is quite accurate with my Contax bodies. For my 28 mm and 35 mm Nikkors, they are not marked with the C on the barrel and focus is likewise accurate.

All true, but if the cost is the same I would prefer buying a lens with the correct flange distance over one where the depth of field hides the fact that the flange distance is wrong.

 

[Scrambler]

I have a mid-70s Leica-threaded J-12 currently mounted on my CV Bessa R. I have read in many places that this is impossible and in others that it is achievable. The trouble is the huge variation in glass used in J-12 manufacture. So I wonder how much space is lost in a postwar Contax and whether it really excludes all J-12 builds given the glass variations? I really don't know, but given the CV cameras actually have 2 shutters I wonder if the Contax IIa has greater shutter thickness?

If the J-12 glass was known to be a short version, is it worth trying?

The testing plan on a Leica thread camera is to have the lens at minimum focus when mounting it, to open the shutter and watch the lens come through. Some prefer the shutter closed.

Of course the risk is to the lens and the shutter when it closes, so another option would be to make a paper cylinder the exact depth of the mount-to-shutter distance in the camera and place that around the lens, checking the protrusion by eye. You could double check vs the Kiev using the same technique to be sure the technique was working.

 

[farlymac]

Nikon made rangefinder lenses for three different mounts, LTM, Contax, and their own mount that was supposed to be a direct copy of the Contax, but ended up with a slight difference. When discovered Nikon started making lenses that exactly matched the Contax mount. These lenses were labeled Nikkor-C (the lenses for their own mount became Nikkor-S).

Not quite. Nikkor-Q·C (as it appears on the 13.5cm 1:3.5) means a coated lens, and you'll see this on the lens name ring whether it is an S mount or C mount. The Contax mount Nikkors have a 'C' engraved in black on the side of the lens barrel. You only see this on lenses longer than 50mm since those are the ones affected by the mount difference. (see below, click on the image for a larger view)

PF


Zeiss Contax IIa with Nikkor-Q C f3.5/13.5cm & 'C' by P F McFarland, on Flickr

 

[farlymac]

I have a mid-70s Leica-threaded J-12 currently mounted on my CV Bessa R. I have read in many places that this is impossible and in others that it is achievable. The trouble is the huge variation in glass used in J-12 manufacture. So I wonder how much space is lost in a postwar Contax and whether it really excludes all J-12 builds given the glass variations? I really don't know, but given the CV cameras actually have 2 shutters I wonder if the Contax IIa has greater shutter thickness?

If the J-12 glass was known to be a short version, is it worth trying?

The testing plan on a Leica thread camera is to have the lens at minimum focus when mounting it, to open the shutter and watch the lens come through. Some prefer the shutter closed.

Of course the risk is to the lens and the shutter when it closes, so another option would be to make a paper cylinder the exact depth of the mount-to-shutter distance in the camera and place that around the lens, checking the protrusion by eye. You could double check vs the Kiev using the same technique to be sure the technique was working.

From what I understand of the J-12 linage, it wasn't originally produced in LTM, but later on as the lens became popular some were converted, and then the factory started making them in both mounts. It still is true they won't fit quite right on a Contax IIa, if at all, but I've seen plenty of folks use the LTM versions on many different cameras with no issues.

One thing you have to look out for is if the lens does contact something in the light box, it can wear the paint off of the edges of the rear element, and this will cause internal flares so you need to make sure the paint is intact on all side surfaces of the lens elements or you'll get some interesting arcs of light on the negatives.

PF

 

[Scrambler]

Ok, a bit of reading outside this thread and it turns out the issue is a narrower light box. People who have tried say the lens cannot be inserted. So I'm afraid nothing will fix that. Given the East v West Zeiss wars, I wonder if it was actually not accidental.

Please ignore my previous post.

 

[farlymac]

Ok, a bit of reading outside this thread and it turns out the issue is a narrower light box. People who have tried say the lens cannot be inserted. So I'm afraid nothing will fix that. Given the East v West Zeiss wars, I wonder if it was actually not accidental.

Please ignore my previous post.

It has more to do with the redesigned shutter in the IIa requiring more space inside the camera body, and that the body was shrunk just a little to make it easier to handle. Thus the light box had to shrink too and the pre-war Biogon and J-12 became casualties. Had it been something to do with East vs West they would have also changed the mount so you couldn't use any of the old lenses. That would likely have killed the camera sales.

PF

 

[Highway 61]

It has more to do with the redesigned shutter in the IIa requiring more space inside the camera body, and that the body was shrunk just a little to make it easier to handle. Thus the light box had to shrink too and the pre-war Biogon and J-12 became casualties. Had it been something to do with East vs West they would have also changed the mount so you couldn't use any of the old lenses. That would likely have killed the camera sales.

PF

It is now well known that the IIa was designed during the war, there are many proofs for that (blueprints and brass parts of the prototype). The goal of the Hubert Nerwin team was to get a smaller Contax and to eliminate the shutter ribbons and leather cords problems of the prewar shutter, designed in 1935. As a result, yes, the prewar Biogon 35, of which the J-12 is a clone, became uncompatible with the new body. This has nothing to do with East vs West indeed.