Voigtlander LTM to M mount adapter off-axis?

Discussion in 'Rangefinder Forum' started by gerkshinobi, Jan 9, 2012.

  1. gerkshinobi

    gerkshinobi Member

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    I purchased a Type II voigtlander LTM to M mount adapter and mounted my 50 1.5 summarit to my m7 and noticed that the lens does not mount the center of the lens at the center point of the camera. It makes shooting a bit weird, but has anyone else experienced this with the voigtlander adapter? I've attached two pictures with the arrow pointing at the top center of the lens so you can see what I mean. Did I get an off copy or is this just how the LTM to M adapter works?

    photo 2.JPG photo 1.JPG
     
  2. Aron

    Aron Subscriber

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    Based on a quick calculation, your lens might be approximately 0.122 mm closer to the film plane than if it were positioned perfectly (given that the adaptor was machined within tolerance), like say a Leica M lens (your lens seems to need a 45 degree extra turn to lock it securely and the Leica thread mount is M39 with 26 TPI). I would do a focus test wide open at 1 meter distance this way and also with a thin shim between the lens and the adaptor to see if there is a difference.

    Let us know if you can see a difference with your enlarger's head cranked to the max.

    Also, how is the infinity position WRT your camera's rangefinder?

    EDIT: After looking at a few photos of mounted Summarits, this sort of misalignment actually appears to be rather typical:

    http://farm5.static.flickr.com/4007/4514278043_296d859b92.jpg

    http://farm3.static.flickr.com/2613/3757201770_d4e73f5f89_o.jpg

    http://www.flickr.com/photos/rst90274/534173980/sizes/l/in/pool-1618922@N23/

    Do the focus test, it will tell more than an hour of theorizing.
     
    Last edited by a moderator: Jan 9, 2012
  3. sandermarijn

    sandermarijn Member

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    The thing that matters for correct lens-to-film distance is the thickness of the adapter flange. The orientation of the threading is only relevant for convenience and esthetics (both of which are important as well).

    I have used two China-made LTM-M adapters and both were a bit off in orientation, but not by as much as the OP's. Focus was perfect as far as I could tell.
     
  4. Aron

    Aron Subscriber

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    Point taken. I was thinking too hard (well this is not that hard, anyway:smile:) on the orientation that didn't think about the obvious. So, yes, probably simply the two threads start at different angles.
     
  5. Paul Goutiere

    Paul Goutiere Subscriber

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    I have the same Voigtlander adapter and the 15mm Heliar in LTM and I have the same issue with the adapter and the lens, in that the center points won't line up.
    They were out by about 5 degrees as I installed the lens with the adapter on my Leica Ms. When I installed the lens on my iiif it was out the same amount in the other direction.
    I was a little concerned, at first, that the built in hood wings would cause vignetting, but that didn't happen. The problem is only aesthetic.

    I found a partial solution, that seems to work just fine:
    -On the base of the Heliar are 4 screws. Remove the screws and remove the LTM base.
    -You then will find there are about 5 threaded holes assigned to the 4 screws on the main part of the lens.
    -Realign the base to accommodate the adapter and the center lines of the camera. I had to use the very last set of holes on mine.

    Of course this won't work on a Leica lens and maybe only on the Heliar. The lens is badly out of align on my iiif unless I align the lens base to accommodate the
    camera.
     
  6. gerkshinobi

    gerkshinobi Member

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    thanks, those photos were definitely a big help. i wonder if there is another adapter that allows the lens to line up with the center at the top or not. i have a roll of film at the lab right now, going to pick it up later in the day, so we'll see how it turned out.

    during your search did you find any photos that show the summarit mounted in the correct orientation with the voigt adapter?

    yeah, i was concerned with the hood as well. i currently don't have a hood for the lens to test it out though. it seems the xoons hood is rectangular which would make this off-axis mounting even more apparent if the hood angle cannot be adjusted to compensate.
     
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  7. Aron

    Aron Subscriber

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    On all the photos I looked at (not many), the lens wasn't perfectly aligned, whether there was an adaptor between the lens and the body (Leica M), or not (Barnack). Use Google to see it for yourself.

    You could either get the lens adjusted by a repair tech, or get an uncut adapter (unlikely...) which you can take together with the lens to a machine shop so they can cut the M39 threads exactly the way you need them to start.

    If the photos turn out fine (I have little doubt), I would just leave it the way it is and after a few rolls you wouldn't really notice it anymore.
     
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  8. jochen

    jochen Member

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    Hello,
    I have a Summarit, a M 6 and a IIIf. On the IIIf the Summarit is perfectly aligned with the index at the 12 o'clock position. Then I tried it with three different original made by Leitz Wetzlar LTM to M-adapters (for 50 mm, 90 mm and 135 mm) on my M 6. Result: With all three adapters the Summarit on the M 6 is exactly as misaligned by about 45° as on your photos. So your Voigtländer adapter and you Summarit seem to be o.k.