Carl Zeiss Jena 5cm f1.5 converted to Leica Mount.

[Brian]

Step by Step photo show of the conversion.

Start with a Pre-war or Wartime Contax mount Sonnar, SN below 3Million, and a Jupiter-3 in LTM.



The optics simply unscrew from the J-3. The Contax lens requires that this set screw be removed.



Optics Modules out:

[Brian]

I use the lens on a Canon III to measure the distance to a fixed target, a lamp. Then I use the through the lens viewer to shim the lens so that the actual focus matches the measured distance. I do this for 5m, 3m, and 20m.

[Brian]

Last step is to make the Aperture ring line up again with the red dot on the focus mount.

Mark the point, unscrew the newly shimmed optics module, take out the three set screws. Move the aperture to line up on the new mark, tap out new holes, put the set screws back in. This is the hardest part. Holes must be deep enough so the screws go in all the way, do not hang out.





After putting in the three set screws for the aperture ring, screw the optics module back into the focus mount. I always test the focus again with the viewer.

The marked point is where the Canon III and the TTL viewer agree. This is good enough for close-up and wide-open.

[Brian]

With the M-Mount adapter, on the M3.