RB 67 lens repair source?

Discussion in 'Medium Format' started by Rick Helmke, Nov 18, 2020.

  1. Evening everyone,

    I have lens I’m having a problem with. It’s a 250mm for the RB 67. It’s in beautiful shape but the shutter is not working properly. When I fire it mounted to the camera it closes but doesn’t open and close again to expose the film. It could be that I am doing something incorrectly but 7 other lenses work properly. I have tried it off of the camera with the same results and on two different bodies so either something is broken or I’m not doing it right. Where is a good repair outfit that knows this system? I used a place I think in Massachusetts a couple years ago for a sticky aperture on an older Nikkor zoom but I don’t know if they will do this. Thanks.

    Rick H.
     
  2. Is the mirror lock up knob on the lens in auto mode?
     
  3. There are two switches/knobs on this lens. One is clearly a switch for proper flash sync and the other is a knob that has a red N and an orange M. I normally leave that on the N setting. The knob also has what appears to be access to a cable release. The camera body also has one on the shutter release button. As long as I have used the RB system I never figured that out. I don’t use mirror lockup for anything and got all mine used and without instruction manuals and I never worried about it. This problem though is a new one on me.

    Rick H.
     
  4. The N (normal) setting is for auto mode. The shutter inside the lens trips when you press the main release button on the bottom right of the camera body. However, if you switch to M (manual), the shutter in the lens will not release when you press the main release on the body. Only the mirror will flop up. You have to switch the lens back to A to release the shutter.

    Of course, the best way to handle this is with a cable release. If you screw one into the lens knob in the little hole in the middle, then you can release the shutter with the cable release after you release the main release on the body. That one also has a hole for a second cable release. That way you can use two cables or Mamiya double release cable that activates both in succession. Or, if you're in N mode, you only need one cable release on the main shutter release button on the body.

    The purpose of the N mode is to reduce vibrations. First, you release the main release that locks up the mirror. Then after a couple of seconds to let the camera shake to settle down, you release the shutter in the lens. I shoot with this mirror lock up all the time. Of course, you have to be on a tripod for it to work the best way.

    Check out Butkus.org to download manuals. He has them for different models of the RB67.
     
  5. sometimes these lenses will stick if not set to the "x" flash mode.
     
    orsetto likes this.
  6. Yep.

    This is a known bug with all the older Mamiya TLR, RB and Press lenses. Can't tell you how many times I freaked out with a "broken shutter" on a shoot, then remembered to check the M-X setting hadn't been nudged off X by even a hair. When buying one of these older examples, you'll know it was previously owned by a pro if the sync control is glued or nail polished in the X position.
     

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