Jupiter 12 on Canon Rangefinder - possible?

I've heard that this lens may or may not work (35 2.8) on Japanese/German rangefinders. Some people have reported it working without shims while some have reported working with shims. I've got a Canon 7.

Some people have had problems adapting the Jupiter 8 to non-Russian cameras, such as losing infinity focus below F4.

Is it basically just luck of the draw whether or not these Russian lenses will work on your camera?

There's not much information about the Jupiter 12 specifically in this regard.

I've used the J-12 on a Canon Leica copy (Barnack type "bottom loader") with excellent results, no shims or anything like that needed. The LTM J-12 is not a well made lens mechanically, but it has good optics. The Contax versions had acceptable build quality and very good optics. These lenses are a bargain, particularly the Contax mount versions.

Oh, OK I see you have a 7. Not sure about that camera, it's a good question. My guess is that it would work, but I don't know for sure.

FWIW, I use a Jupiter 12 on a Canon P with no issues. So far as I know, my lens isn’t shimmed, but that’s a variable that you may need to look at. Aside from adjustments like shimming for correct focus, the usual problem with J12 compatibility is the rear element clearing the shutter or other protrusions such as light sensors.

bdial said:

FWIW, I use a Jupiter 12 on a Canon P with no issues. So far as I know, my lens isn’t shimmed, but that’s a variable that you may need to look at. Aside from adjustments like shimming for correct focus, the usual problem with J12 compatibility is the rear element clearing the shutter or other protrusions such as light sensors.

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No doubt about this; also true for the original Zeiss Biogon that was the pattern for the J-12. The original Biogons and J-12 cannot even be mounted on a post-War Contax IIa or IIIa, because the shutter on those was made thicker than the pre-War originals -- and the thicker shutter will contact the rear element when the lens is set to infinity focus. This is why I'll be looking specifically for a pre-War body when I start shopping for a genuine Contax -- because I like my Jupiter 12 and don't want to give it up. I have one that's badly scratched on the back element -- I bought it cheap thinking I could fill the scratches with black ink or similar, but apparently that doesn't work as well for rear element damage as it does on a scratched front element.

That's so interesting that you guys haven't had any problems. I read comments saying the 2.8 aperture and wide angle accounts for any focus problems, but that the focus may still be off a little bit but you may not notice.

Have you guys noticed any problems when focusing wide open at infinity? I've been told that focusing at F4 at infinity might be a better idea to avoid problems with that.

Good to know about the Contax Donald. I've heard something about the pre-war contaxes being compatible with the Russian lenses in general be default, so it may be a good purchase if you plan on using Russian glass? (Might want to check, I think we ran across that comment on a previous thread).

You might think about buying a broken Jupiter 12 and swapping out the rear element. I've also heard you can polish out scratches using some sort of glass polish and maybe a dremel tool, but that might mess up the focus if it changes the thickness of the rear element.

Donald Qualls said:

No doubt about this; also true for the original Zeiss Biogon that was the pattern for the J-12. The original Biogons and J-12 cannot even be mounted on a post-War Contax IIa or IIIa, because the shutter on those was made thicker than the pre-War originals -- and the thicker shutter will contact the rear element when the lens is set to infinity focus. This is why I'll be looking specifically for a pre-War body when I start shopping for a genuine Contax -- because I like my Jupiter 12 and don't want to give it up. I have one that's badly scratched on the back element -- I bought it cheap thinking I could fill the scratches with black ink or similar, but apparently that doesn't work as well for rear element damage as it does on a scratched front element.

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The focus problems due to (apparently) the Russian screw-mount rangefinders being designed for different fiducial "50mm" focal lengths are a strong function of focal length. Basically, the accuracy needed goes as the square of the focal length, and linearly with aperture diameter. So people worry about this a lot for telephotos and fast normals shot wide-open, and not so much for wide angles.

The other problem referred to is the large Jupiter rear element, and it's not possible to give a blanket answer about whether it will fit every model of rangefinder. And it also depends on how careful you personally can be when mounting it.

brainmonster said:

Good to know about the Contax Donald. I've heard something about the pre-war contaxes being compatible with the Russian lenses in general be default, so it may be a good purchase if you plan on using Russian glass? (Might want to check, I think we ran across that comment on a previous thread).

You might think about buying a broken Jupiter 12 and swapping out the rear element. I've also heard you can polish out scratches using some sort of glass polish and maybe a dremel tool, but that might mess up the focus if it changes the thickness of the rear element.

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The only incompatibility I know of between the Kiev 2, 3, and 4 models and Contax II, III, IIa, and IIIa and their respective lenses is that the Jupiter 12 and pre-War 35/2.8 Biogon must not be mounted on the Contax IIa/IIIa (and any other Contax-mount RF camera should be checked carefully) because of the thicker shutter. The first Kiev 2 and 3 models were built on the same actual Zeiss equipment that was used to build the pre-War Contax II and III -- the entire factory was transported to the Ukraine after the War. Kiev 4 was a slightly simplified camera, to be easier to manufacture, and incorporated some of the same changes that went into the Contax IIa/IIIa models -- flash sync, no folding foot around the tripod socket, etc.

Where compatibility issues arise is with Nikon's (almost) Contax mount RF cameras. These are perfectly compatible with Contax/Kiev lenses that use the internal bayonet (50mm only, AFAIK) and within tolerance on outside bayonet lenses shorter than 50mm, but won't focus correctly with longer Contax and Kiev lenses (which all use the external bayonet).

In fact, I did buy a partly disassembled LTM Jupiter 12 (optically identical) for $10 plus modest (slow) shipping, I just haven't gotten around to swapping the rear groups and testing the Contax-mount lens for optical quality. This became less urgent, as before the junker lens (with good glass) arrived I bought a second Contax-mount Jupiter 12 from a Photrio member and I've been quite pleased with it. I don't use wide angle as much as I do normal, and the Jupiter 12 has that idiosyncratic inside aperture adjustment, which makes it, um, interesting to use with filters.

I probably should get around to doing the swap and test so I can sell off the repaired Contax-mount lens, or explore what would be involved to transfer the entire optical block from the presumed damaged LTM (Fed, Zorki) focus unit it's partly removed from into the good Contax (Kiev 2,3,4) focus unit.

Honestly, I think there are inconsistencies in the exact flange distance of different Soviet lenses, because they were made not to be instantly compatible with every m39 camera, but to be calibrated for a specific camera.

I have two m39 normals from the FED labor commune and one from the Kraznogorsk mechanical works plant. One from the FED plant and the one from KMZ both focus accurately on both my FED 2 and my Zorki S, while the third is somewhat inaccurate on the FED 2 and greatly inaccurate on the Zorki S.

I don't think they're hard to calibrate, I just haven't gotten around to doing it yet.

So my answer is that your Jupiter lens may work great or it may need to be calibrated. The problem will be lessened at small apertures, with any problem ameliorated almost completely from about f/8 up.

So what's the verdict on this lens? I'm just a hair away from buying one, but I stopped myself. I have a canon 50mm 1.8. I heard the virtues of the Jupiter 12 extolled, at least form film (it doesn't work well on digital). But do I really need another lens? The Canon 50mm 1.8 is plenty good.

I'm sure it depends on the copy, but how good is this lens really? I've heard they can vary between very good and mediocre. I'm looking at one made by KMZ from 1960. I may just save my money up for something that would change my photography more drastically, or do something I can't really already achieve rather than collecting more stuff.

brainmonster said:

So what's the verdict on this lens? I'm just a hair away from buying one, but I stopped myself. I have a canon 50mm 1.8. I heard the virtues of the Jupiter 12 extolled, at least form film (it doesn't work well on digital). But do I really need another lens? The Canon 50mm 1.8 is plenty good.

I'm sure it depends on the copy, but how good is this lens really? I've heard they can vary between very good and mediocre. I'm looking at one made by KMZ from 1960. I may just save my money up for something that would change my photography more drastically, or do something I can't really already achieve rather than collecting more stuff.

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A wide angle? Should be safe. There may be some unsharpness wide open but it shouldn't be significant. They're made for the same mount, there were just quality control issues at some Soviet plants. This gets exaggerated because lots of people get Soviet cameras that have problems... but many of them are in their sixties! So Soviet quality control is not up to the standards of the germans they learned the trade from but it's not terrible. I'd say go for it. The only thing that would give me pause is that it's an ugly lens and you're about to put it on a handsome camera...