80mm C high shutter speed problem

Discussion in 'Medium Format' started by tom_derosa|1, Jun 7, 2016.

  1. I recently purchased a 500C/M kit from a trusted eBay seller. It was CLA'd by him and then sold to me. I put a roll of Tri-X through it and got it developed. To my dismay, none of the photos came out at all. A few had bright spots in one corner, but all of them were underexposed greatly. These were shot at small apertures and high shutter speeds as they were taken on a sunny day with 400 speed film.

    Before the first roll was developed, I started on a 2nd roll. I got the call about the failed roll while I was half way through my 2nd roll. I finished the roll quickly to see if maybe I didn't load the film properly or just wasn't using the camera right, but when the 2nd roll got developed, 3 pictures came out and the one that looked normally exposed with no issues was a shot taken at f5.6 and 1/30".

    Since then, I've been doing tests to see if I could isolate the problem and what I'm seeing is that at higher shutter speeds, sometimes the shutter isn't opening.

    My test was done with the lens set at 1/500" and f2.8 on self timer so I could record the actuation in slow motion. The first video is what I believe is the camera operating normally. The second video, you can see the shutter moving slightly, but not nearly enough to let any light in.
    My question is this: If this lens was CLA'd, is there anything simple to check by opening up the front or back of it? The guy I bought it from is on vacation for 2 weeks and I'd rather not have an expensive paper weight for that long.
    Thanks, Tom
    http://vid86.photobucket.com/albums/k94/gtxtom/pass_zpsoirjpvwy.mp4
    http://vid86.photobucket.com/albums/k94/gtxtom/fail_zpsjsnqcchr.mp4
    [​IMG]
     
  2. If you open up the lens to fiddle with he shutter you
    will likely extinguish any possibility of returning it. If
    I were you I'd operate the camera without a back,
    pointed at a light, to see if the shitter is actuating or
    not.
     
  3. I'd also be reconsidering the term "trusted" in your
    first sentence.
     
  4. Remove the back and look through the lens while using an electronic flash sync'd to the lens. You will get a clear view of the shutter. It should appear fully open, at any speed.
    The fog pattern on the film suggests a problem with the auxiliary shutter (bard door) or mirror synchronization. A faulty shutter would affect the entire film area uniformly.
     
  5. There's 2 vids at the bottom of my post showing 'normal' operation and a failed firing. Please watch them.
     
  6. Based on description alone (you described the symptoms good enough) the shutter either
    wasn't properly serviced or it is broken.
     
  7. PS. There is nothing "simple to check" inside a
    Hassy lens or shutter.
     
  8. Thanks. Yea I think I worded my question poorly. I guess I was looking more for a "are there any adjustments that can be done in the mean time that would help my problem".
    I appreciate the help.
     
  9. There are no adjustments, per se. The timing is strictly mechanical. Your video is of no help. The frame rate is far to slow to show the operation, correct or otherwise, of the shutter. Maybe if you can bump your video to 3,000 fps or so it would be a useful diagnostic tool.
     

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