500cm Mirror Pre-Release Malfunction and Focus problem

Discussion in 'Medium Format' started by scott_micciche, Nov 23, 2016.

  1. Hello,
    I'm new to the site but have been searching for a few days to see if anyone had posed this question.
    The issue was the mirror pre-release mechanism not working. I have since fixed the issue by disassembly and using Dick Werner's instructions, pried the lock up lever while re-assembling the body. I took the opportunity to lube the main gear and a few other spots he recommended with clock oil. The body is now extremely smooth and snappy.
    Since I acquired the body, lens and back, I've noticed the focus a bit off. I'm aware of the 3 pads under the mirror issue and I am going to be sending the camera in for a CLA, but I wanted to see if the issue could also be caused by the malfunction of the mirror pre-release lever.
    I will be taking some shots using a back/front focus test chart I use for autofocus lenses, and just need to develop them so I can use the images when the camera goes in for service. I figure it will help the tech narrow down any issues.
    Thanks for any information and a great resource (site).
  2. I managed to grab a few shots of the back focusing issue. I'm sending the body into David this week as soon as the holiday craziness subsides.
  3. It could be the three pads under the mirror, which is not an easy thing to solve and it is normally not included in a CLA. Check with David about this repair.
    You might check by repeating the test with the camera upside down and sideways. If the pads are gone, the mirror will move inside its frame.

    On a final note, do not expect "pixel" or "grain" perfect focus at large apertures with an over 30 years old device. For that you will need a recent digital back capable of live view.
  4. The camera was returned from David Odess and it's now in perfect focus. Aside from the full CLA on the body and a repair to one of my A12 backs, an adjustment was made to the focus screen height. His knowledge is vast on these camera bodies and backs. I'm glad to have the camera back and it's smoother than ever!

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