Simple Shim for LTM adapter to adjust infinity?

Discussion in 'Leica M and LTM Lenses' started by uhoh7, Sep 4, 2015.

  1. uhoh7

    uhoh7 Leica Place Regular

    163
    Oct 14, 2014
    Brian or anyone :)

    I have the CV 75/2.5.

    On the M9 it goes past infinity with all four of my LTM adapters, just a tad, but enough to ruin the distant details.

    My CV 90/3.5 is fine.

    What would be the simplest way to shim it?
     
  2. Brian

    Brian Super Moderator Subscribing Member

    Apr 3, 2013
    Does the RF go past infinity, the actual focus, or both?

    Going past infinity means the lens needs to be moved out. If the actual focus and the RF are both out, I would use a thin later between the lens and the adapter.
     
  3. uhoh7

    uhoh7 Leica Place Regular

    163
    Oct 14, 2014
    Well, you move the lens to the stop. The patch is clean with distant objects. Focus is past infinity.

    At first I thought the lens had some flaw LOL. But on the A7 it is sharp at infinity. So I backed off a tad on the M9. Patch split. It's sharp.
     
  4. Brian

    Brian Super Moderator Subscribing Member

    Apr 3, 2013
    I do not know how to disassemble that lens, it is back-focusing which means the optics need to be moved out farther from the image place. If it cannot be adjusted with a simple shim, then using the spacer between the lens and adapter will work. Try that first, if the RF and Focus do not agree : then put the same amount of shim material on the RF cam.

    A real "hack". Try to find instructions for moving the optics from the focus mount.
     
  5. uhoh7

    uhoh7 Leica Place Regular

    163
    Oct 14, 2014
    RGR TY so much :)

    Tin foil for shim? I can dedicate one M adapter to this lens.
     
  6. Brian

    Brian Super Moderator Subscribing Member

    Apr 3, 2013
    Tin foil is ~0.08mm, enough to fix most FSU lenses to the Leica standard.

    I would start there.