Infinity locks on lenses

Discussion in 'Classic Manual Cameras' started by straw_man, May 31, 2015.

  1. My Leica screw mounts and postwar Zeiss Contax lenses are locked when set at infinity. Easy to unlock, but why are the locks there in
    the first place?
  2. SCL


    It makes them easier to mount & dismount from the camera body.
  3. For the Elmar 50/3.5, it's just to give you a grip.
    On the other lenses, it's a handle to prevent you from putting torque on the bars in the focusing helical that keep the lens proper from rotating. Done repeatedly, that can make the helical loose.
  4. As the others have said, but they still manage to annoy me :)
  5. I agree with the reasons for their origination. Most of my lenses are constrained from adjusting the range past infinity or
    closer than the minimum allowed, so I see infinity locks are largely useless.
  6. The early Leica lenses focused by rotating the lens. Even the Leica A had an infinity lock. I believe that it was to assure the photographer that the lens had not been left or accidentally moved to a closer focusing distance, which was an easy mistake to make.
    Personally, I like them and feel more comfortable using a lens with the infinity lock, even on parallel-focusing lens mounts.
  7. Sometimes it takes some force to get those lenses off the camera. I appreciate an Infinity Lock that does not put the stress on the body of the lens or the helical after using the Jupiters.

    Don't like Infinity Locks- easy to remove, or get a Jupiter.
  8. Also on Canon & Schneider-Kreusnach LS-TM lenses. I guess for landscapes, the lenses are pretty much always within focus as soon as the lens cap's off, even at wide apertures. They are only ever on 28/35/50 lenses, where this is the case, and not always used; eg on the Summaron 35 f3.5 with M3 goggles.
    I don't mind them, as long as they remain easy to unlatch. They are more of a problem when focusing gets stiff, and that's something that should be attended to anyway.
  9. The Canon 135/4.0 doesn't have one, but the focus ring is far enough out that there is a place to grab the barrel closer to the mount.
    Yes, it is very inconvenient to have to focus the lens all the way out when removing it, and it probably puts strain where it shouldn't be. Not so obvious the other direction.
    But the 135/4.0 doesn't have a full ring for the rangefinder coupling. I think for that one, you are supposed to run it all the way out first to reduce wear on the rangefinder mechanism.

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