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Rollei/Voigtlaender QBM lenses on Minolta/Sony A mount

Discussion in 'Sony Chat' started by SqueamishOssifrage, Jun 29, 2018.

  1. SqueamishOssifrage

    SqueamishOssifrage Well-Known Member

    In the thread below this one (Sony Alpha SAL85F28 85mm f/2.8 A-mount), I mentioned that, apparently, this combination could not work. I accepted what I had been told, like a good boy, and forget about it. I decided to look at this for myself and found the following:

    1. The flange distance in both cases is 44.5mm.
    2. The lens flange thickness is 1mm in both cases.
    3. The shoulder diameter of a QBM lens is 43.0mm.
    4. The throat diameter of an A mount lens is 43.3mm.
    5. The flange to lens body on QBM is 7.6mm.
    6. The flange to lens body on A mount is 4.4mm

    What this indicates to me is that by removing the flange on the QBM lens, then an A mount lens flange could be mounted in its place on a 3.2mm spacer, easily machined out of brass.

    As it only takes the removal of three screws to get the QBM flange off, I am going to do this, ant then see if one of my M43 to A mount adapters will actually fit over the QBM shoulder. If it does, I will remove the entire flange from a surplus A mount lens and see what can be done.

    The only immediate challenge is to find the M42 adapters, after moving my man-cave from the old stables to the house. I have no idea where they are!
     
  2. neilt3

    neilt3 Well-Known Member

    When I need a little odd and end type thing , I always end up just buying another .
    The time and effort needed often out weighs the cost of another .
    After the new piece arrives , the one I had then turns up . Always !

    Still in the process of setting up my dark room , so everything got boxed up and hasn't been organised yet .
    Have fun .
     
  3. SqueamishOssifrage

    SqueamishOssifrage Well-Known Member

    That's how I got my second one! I have actually found the second one (but not yet the first, which is attached to a rather nice Zeiss Jena 135mm). Now I just need to get it to a machine shop to mill away the 42 mil thread so it will slide over the shoulder of the Voigtlaender so I can measure the precise thickness of the spacer I will need.

    Good luck with the darkroom - if I tried to set one up here my life expectancy would face a severe downturn! :eek::D
     

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