Takumar auto/manual switch - no difference?

Discussion in 'Adapted Lenses' started by Steven, Nov 23, 2013.

  1. Steven

    Steven Mu-43 All-Pro

    May 25, 2012
    I bought a 50mm/1.4 Takumar and it has this auto/manual switch on the side. Aperture is possible to change in both modes, so I guess it doesn't matter how to have this switch set?:confused:
  2. dwig

    dwig Mu-43 Top Veteran

    Jun 26, 2010
    Key West FL
    When the lens is not mounted on a body or adapter it should work as follows:

    • A position: rotating the f/stop ring should make no visible change in the iris
    • M position: rotating the f/stop ring should cause the iris to change in size.
    • A position and pressing the pin on the rear: With the f/stop ring set to anything of than the lens' maximum aperture (f/1.4 in your case), pressing the pin should cause the iris to stop down from its maximum postion to the appropriate size for the aperture set on the f/stop ring.

    Your "problem" could be one of the following:

    1. The lens is mounted on an adapter that presses the pin. These are somewhat common as many non-Takumar M42 lenses lack the A/M switch and require that the body or adapter press the pin.
    2. The lens is mounted on an M42 body and either the shutter is open or the meter is turned on
    3. The lens is faulty

    In the case of #3, several problems could exist. if the lens always changes the iris size when you turn the f/stop ring then it could be that the pin or its internal mechanism is stuck in the "pressed" condition. If, on the other hand, nothing you do makes the iris close at all then the iris is frozen in the open position. This latter flaw is not uncommon and generally requires that the lens barrel be torn down and both the iris and the focusing helicoid be cleaned and the focusing helicoid be relubed.
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  3. jamespetts

    jamespetts Mu-43 Top Veteran

    May 21, 2011
    London, England
    When using a Takumar lens with an auto/manual switch on a Micro Four Thirds body with an adapter (or any body that is not a native M42 mount body), set the switch to "manual". If you set it to "auto", the lens will not stop down when you turn the ring.
    • Like Like x 1
  4. dwig

    dwig Mu-43 Top Veteran

    Jun 26, 2010
    Key West FL
    When using my Takumar 55mm f/1.8, I generally do the following:
    1. set to M and determine the f/stop that I need to use
    2. switch back to A to focus
    3. switch back to M to shoot
    4. repeat #2 and #3 for subsequent shots
    It's fast and more convenient to use the A/M switch like a "pre-set ring" than to manually open and close the aperture, counting clicks or reading the scale, for every shot.