Jupiter-12 on S2

[Ed Schwartzreic]

I just got a clean Jupiter-12 for my S2, after really liking the lens in LSM on my Leicas. While the J-12's focus turns smoothly and freely off of the camera, the lens bayonets quite stiffly onto the S2, and focus cannot be turned more than 30 degrees before binding completely. It has nothing to do with the protruding rear element; if that is unscrewed and removed, the same thing happens.

What gives here? :bang:

Ed

 

[Sonnar Brian]

Welcome to the world of FSU quality control. I have had to file down every FSU lens to use on my Nikon RF's. It is hard to tell you what is catching without seeing it. Chances are the lens is not picking up the inner bayonet used to latch to the RF.

Does it bayonet onto the camera easily, or do you have to force it?

Did you remember to turn the camera and lens both to infinity before mounting?

 

[Ed Schwartzreic]

Thanks for the reply, Brian. I have now got it so that it bayonets smoothly onto the camera. I can get it to turn fully, but it binds significantly in the middle range, let's say 2.5m down to 1.5m. It is not smooth anywhere -- i.e. something is binding -- bit it is better from infinity to 2.5m, and below 1.5m. Do you have any idea what part(s) is / are binding?

Ed

 

[taffer]

Ed,

I had this same problem (the lens offering clearly more resistance to turn in a given range) on a J12 mounted in a good working Kiev. The resistance was not that much and eventually it ended getting better with use.

So it seems to be a sort of common behaviour on that lens, unfortunately.

Do you need to apply too much force in order to turn it in that range ?

Oscar

 

[Ed Schwartzreic]

Oscar,

I would definitely say it is too much force, except for infinity to 4m, where it is bad but usable. I can get it all the way around, but could never shoot with it like that. If I knew exactly what to file down, I would. I figure that one or more of the lugs is too large in one dimension, but that is just a guess.

Ed

 

[taffer]

That's a pity, the J12 is not a bad lens at all. The Nikkor 35/3.5 doesn't seem to go for an unreasonable amount and would probably give you less fitting problems than the J12.

Also, if you have the option to test some Jupiters maybe you can find one that fits properly. Having the option is the tough part...

 

[Stanton]

Ed -- I use a Jupiter 12 on my S2 and SP with no probllems. I think the comments about quality control are correct. There were simply too many variations or tolerance in the manufacturing. I had the 85mm f2 Jupiter in Kiev - Contax mount and it would not mount on either of my Kievs. I returned to the store where I purchased it. I found one in the store's stock which fit my Kievs, and the one which I returned fit the store's Kievs but not mine. Go figure. In any case, I have found the Jupiter 12 on the S2 and SP to be entirely satisfactory to me. I hope you find a solution. Dave

 

[wlewisiii]

Do you imagine that a lube job might help? There are horror stories of metal filings in the works that might cause something like you describe.

William

 

[Doug]

You might try mechanics' bluing, a kind of blue dye that is applied to one of the two mating surfaces, and is scraped away by attempting to fit ill-fitting parts. This shows where the binding is occurring. You can then do a bit of fine filing on the binding spot on the lens and re-apply the bluing and try fitting again. I'd be concerned about damaging the Nikon's lens mount...

 

[VinceC]

If this is your first non-50mm lens for the Nikon S2, you should also be aware that the built-in lens mount has to be set to infinity before mounting a wide or telephoto. Not doing so can cause serious binding.

Beyond that, I'll chime in with the quality-conntrol observation. My version of the Jupiter-12 35mm lens is from 1960 and has always fit both my Kievs and Nikons without any problems. It takes great pictures and I still carry it around once in awhile when I'm trying to keep weight to a minimum.

 

[Sonnar Brian]

If the lens turns freely when not on the camera, but binds when on the camera, you have me worried. If the part of the lens that makes contact with the Nikon's internal coupling is at an angle, it would bind and possible damage the Nikon's RF coupling. Imagine it being at a slight angle once mounted and forcing the Nikon's coupling around at that angle.

If the lens binds when off of the camera, a lube job might help. Sometimes the helical of the lens is a problem. But, again, if it turns easily off the camera, but binds only after mounting, I would quit using it until the problem is resolved. Look to see if the rear module is loose.

 

[Ed Schwartzreic]

Thanks for all the posts and help.

With a bit of judicious grinding and re-blackening of the J12's brass lugs, I have improved matters considerably.

Ed

 

[Sonnar Brian]

I got the results of the "adjusted" j-12 on my S-2, and experienced some of the same "mod-range" binding as Ed did. Relubing the center collar of the J-12 got rid of the unevenness. The collar has to "ride" the internal bayonet on the camera's helical. If it does not "float" on it freely, you get binding. I lubed it, and it is smooth enough to turn with the focus wheel. The results were also quite good. Not as good as the Nikkor 5cm F2.5, but better than the Nikkor 3.5cm F3.5.