I just got a 1960 chrome Jupiter 12 in Kiev/Contax mount. Took it for it's trial run today and discovered that I can't focus it to infinity. Thought it might be the RF on my 4am that was out of alignment, but that isn't the issue. It focuses fine with my Helios 103 attached. When I first mount the J-12, the two images in the RF window line up, but after the focusing knob is turned, they won't come back together at infinity.
I have to file something know, don't I?