Mamiya 645 Pro Shutter not Firing on Auto-Shutter Speed

Discussion in 'Medium Format' started by eaw8r8, Jul 4, 2020.

  1. I recently got a Mamiya 645 Pro. It worked fine for the first couple of rolls of film that I shot but recently I've run into a problem. The shutter won't fire on auto-shutter speed anymore. The camera came with the in viewfinder meter and it has been firing when set to "A" but suddenly stopped. As far as I can tell the meter is still working fine, so I can just meter with it and then set my shutter speed manually, but I'm a bit concerned that something that was working suddenly stopped.

    Do y'all have any ideas on how to fix this issue or if there are any (relatively cheap) repair shops in the U.S. working on cameras during the pandemic?

  2. What happens on the manual setting, shutter speed-wise? You may be looking at getting a handheld meter. Besides, those metered finders aren't wildly accurate anyway. Not a huge loss since that set-up was never exactly a 120 p&s camera.
    Last edited: Jul 4, 2020
  3. Manually it fires fine. Today I simply metered through the finder and set the shutter speed manually instead of using automatic and it fired correctly.
  4. Try cleaning the electrical contacts between the magazine back and the camera body, and the contacts between the prism and the body. If the prism can't 'read' the ISO set on the film-back, then it won't fire in Auto mode.

    Also, if this is a newly acquired camera, carefully check that the plastic mirror-rest hasn't cracked. This common issue completely ruins the focus of the camera, and a replacement part can't be obtained.

    I've had so many issues with plastic-bodied M645s (Super, Pro & ProTL) that my sincere advice is to get rid of that camera as soon as you possibly can.
    The metering was great - when the cameras actually worked - but my two Supers and a ProTL have spent more time in repair than in use!
    Last edited: Jul 5, 2020
  5. Confirmation bias, Joe? Have two Supers, both bought used, both function trouble-free after a decade. Maybe give the tarbrush a rest?
  6. That's great for you, but many, many users beside me have suffered the failure of the crappy little mirror brake/rest. Sure, there's an online 3D printer template for it. I had a couple made, and they're even more fragile than the original.

    Confirmation bias - no idea what that psycho mumbo jumbo means - but a multiple failure rate of 3 out of 3 isn't a good record or recommendation for any camera.

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