Need advice on an LTM-NEX adapter

Discussion in 'Adapted Lenses' started by Mellow, Sep 18, 2013.

  1. Mellow

    Mellow TalkEmount Regular

    31
    Aug 18, 2013
    Florida or Wyoming
    Tom
    After being given good advice here, I recently bought a lovely Voigtlander 15mm f/4.5 to use on my NEX-5R and Olympus OMD. As advertised, the lens is great, but there are two issues with all 3 of the LTM adapters I've tried it with:

    1) The top of the lens doesn't 'align' correctly. Normally I wouldn't care much if the f-stops and distances were not centered on the top, but if the petal-shaped lens hood is rotated from center it will cast shadows and not function properly;

    2) Infinity is waaaaaay off. Again, I don't mind a lens focusing a little past infinity, but this one is about a mm off, so I need to rotate the focus barrel almost 1/4 turn to bring infinity into focus. Even when I stop down distant objects aren't in focus when the lens is set at infinity.

    I can solve either of these problems with an adapter, but not both. One of my adapters allows rotation of the sleeve inside the housing, and I'm able to align the top (and hood) of the lens properly. But then I have the problem of infinity focus. I also thought of buying a helicoid adapter to adjust infinity and then locking it in place with a drop of superglue. But the helicoid adapter I already have doesn't center the hood properly, so that doesn't solve the problem either.

    So . . . . does anyone know of a solution? I guess if I could buy an inexpensive helicoid adapter that allows me to adjust rotation that would be ideal. Does such a thing exist? Or is there another solution I'm not aware of?
     
  2. Bimjo

    Bimjo Super Moderator

    Oct 28, 2011
    Washington State
    Jim
    The adapter(s) allows the lens to focus past infinity because it is too short. Take the one with the mount ring you can rotate. Remove the screws so you can remove the ring. Insert shims (beer/soda can) under ring. Reassemble and adjust as necessary.

    A helicoil would work if the lens goes beyond infinity, though it will be a constant adjustment sort of thing, no repeatability at all.

    Depending on what the subject is, focusing to about 2 meters @f/8 gets you from just under a meter to infinity in acceptable focus. You have to define acceptable for you though. ;)
     
  3. Mellow

    Mellow TalkEmount Regular

    31
    Aug 18, 2013
    Florida or Wyoming
    Tom
    Bimjo,
    Thanks, that sounds like it will work, but, sheesh, you'd think someone would make an adjustable adapter. I'll have to look at what I can use for shims.
     
  4. Bimjo

    Bimjo Super Moderator

    Oct 28, 2011
    Washington State
    Jim
    You would think. :)

    You could also try a LTM-M adapter and a M-NEX adapter. That may work just enough differently to work. I did that for my LTM lenses since I have both LTM & M mount lenses. That way I can use the one M-NEX adapter for all my lenses.

    BTW- does one of the adapters you have that comes close to infinity focus have the removeable ring? If so, you should be able to loosen the screws, rotate the ring (with the lens mounted) to line everything up and then re-tighten the screws.