Jupiter 12 mounting issues

[Peter_Jones]

I have just got a Jupiter 12, very good condition, fits well on my Zorki and Fed, but only goes on a couple of threads of the Leica 111c before it gets tight, tighter than I would want to force it. The threads seem clean enough, just out of sync with the leica mount.

Is there a simple way around this (other than just using the Zorki) or is it one to chalk up to experience ? 😕

 

[xayraa33]

what year is the J-12 from?
I had one from the early 1950s that had that problem.

 

[clintock]

I hope it's not the RF arm interfering. Be sure to have the lens set to close focus when you put it on, and once it's on some observe what the rf image is doing when the lens is focused.

 

[Peter_Jones]

what year is the J-12 from?
I had one from the early 1950s that had that problem.

1952 , guess that solves that. Gives me an excuse to look for a nice Fed2 😀

 

[xayraa33]

the Fed 2 can be problematic with certain FSU lenses also.
the RF arm on this camera can sometimes be sitting too high to line up with the lens cam tube.
this can be fixed by slightly bending the RF arm and recalibrating the RF.
other Fed and Zorki models do not seem to have this problem as far as I know.

 

[julio1fer]

FWIW, I have used my 1966 J-12 in a Leica IIIb with no problem at all.

 

[gb hill]

I have a j-12 that is a bit of a problem on my fed2. Sits really well on my zorki 2c which I like much better than my fed 2. Even though the zorki is a bottom loader and the fed is not.

 

[wolves3012]

The J-12 leaves very little room (between the focussing cam and the rear element) for the RF arm to fit into. If the arm is too low it'll scrape along the element, too high and it misses the coupler. Possibly on a Leica the bearing-tipped arm is a little fat? I had to adjust the arm-height on my FED 3a critically for the J-12 but all my other FSUs take it happily (and carefully). Always make sure the lens is set to 1m focus or it's very difficult to start on the threads!

 

[xayraa33]

my 1960 and 1976 J-12s mount ok on my Leicas.

 

[Peter_Jones]

Had to check the RF roller wasn't fouling (it wasn't thankfully). However I did notice a "high" spot between the threads where the thread wasn't cut deep enough.


It fits now ! 😀