>I noticed that the rear optic group has its lenses mounted on screwed modules that does
>not have any shims. It is simply glued in place at a certain position, not fully screwed.
Hard to believe that there were not any shims on the rear group! It makes sense that they could be set for either the Contax standard or the Leica/Nikon standard. I reduced the rear (secondary) shim on a Helios-103 to adapt to the Nikon focal length. Moved the rear group in closer to reduce focal length. Also did the same thing with a post-war 50mm F1.5 Sonnar that was given to me. It had issues, the groups were out of whack when I got it. No secondary shim, had to file a bit to move the groups in.
>not have any shims. It is simply glued in place at a certain position, not fully screwed.
Hard to believe that there were not any shims on the rear group! It makes sense that they could be set for either the Contax standard or the Leica/Nikon standard. I reduced the rear (secondary) shim on a Helios-103 to adapt to the Nikon focal length. Moved the rear group in closer to reduce focal length. Also did the same thing with a post-war 50mm F1.5 Sonnar that was given to me. It had issues, the groups were out of whack when I got it. No secondary shim, had to file a bit to move the groups in.