How to adjust lens cam/focus?

[crusius]

I have four lenses and only one has focus problems (a Voigtlander 35/1.7). It always backfocuses by, it seems, a constant "angle difference" on the focusing ring.

Is there any standard procedure to adjust the lens? I'd imagine it would be just a matter of "remove the mount, loosen some screws, rotate the cam, tighten the screws, replace the mount" or "install/remove a shim" --- but it would be nice if such a procedure was documented somewhere.

Any pointers?

 

[Pompiere]

Here is something to get you started. http://elekm.net/zeiss-ikon/repair/collimate/

 

[ferider]

I have four lenses and only one has focus problems (a Voigtlander 35/1.7). It always backfocuses by, it seems, a constant "angle difference" on the focusing ring.

Is there any standard procedure to adjust the lens? I'd imagine it would be just a matter of "remove the mount, loosen some screws, rotate the cam, tighten the screws, replace the mount" or "install/remove a shim" --- but it would be nice if such a procedure was documented somewhere.

Any pointers?

For the 35/1.7 there is.

- remove the lens mount.
- underneath you see a ring mounted with 3 black philips screws. Loosen those.
- Now you can rotate the black ring and adjust the RF coupling.
- tighten the black screws, put the mount back on and voila.

Note that this will change infinity alignment for the lens as well. It just shifts the RF coupling by a constant amount.

Roland.

 

[crusius]

For the 35/1.7 there is.

- remove the lens mount.
- underneath you see a ring mounted with 3 black philips screws. Loosen those.
- Now you can rotate the black ring and adjust the RF coupling.
- tighten the black screws, put the mount back on and voila.

Note that this will change infinity alignment for the lens as well. It just shifts the RF coupling by a constant amount.

Roland.

Thanks a bunch! I think that this is the problem (constant amount). At least with my 35/1.7 I can focus some 2mm past the infinity mark.