Syncro Compur shutter (or maybe most of it?)

Discussion in 'Large Format' started by ChrisSpeaker, Nov 16, 2017.

  1. OK I have a Syncro Compur shutter that is new to me as well as my first compur type of shutter. Previously I've only owned Copals.

    Upon doing to research I found that most but not all compurs have a self timer mechanism right about at 1-2 oclock position. I have also head there is a variant that does not? Is this true?

    I have included a picture of the offending area of the shutter. If anyone could please tell me if this is correct for this type of shutter or is a piece missing? Thanks!!! DF0_2936.jpg
  2. Likely the self timer lever as shown on the CN-1307-000
    ScreenShot_20171116123613.jpeg ScreenShot_20171116123849.jpeg
    Earlier versions are very similar.
  3. Thanks for your response thirteenthumbs. I though there should be a self timer mechanism button/level there.
  4. The self timer on that vintage are problematic and usually cause the shutter to hang and have to be forced to run down so that the shutter can be used.
    When it hangs press the release lever then push the cocking lever toward the fully released/home position until the full travel of the lever has been reached.
  5. If a self-timer button is fitted; the way it works is to prevent or allow the cocking lever to be pushed past the normal cocking position. The S-T button is a simple catch with a ratchet action that allows the cocking lever to run past it in S-T mode, but not when being normally cocked.

    If the button is broken off, I suspect the cocking lever will be permanently prevented from reaching the S-T position.

    However, there were also Compur shutter variants that never had the S-T button fitted at all. I believe the one shown is such, since it has a preview lever to open the shutter for focussing/viewing.

    If the cocking lever can be pushed beyond the cocking position, then the S-T stop has been removed. Probably after being broken.
    Last edited: Nov 17, 2017
  6. Thanks rodeo_joe for your reply. The shutter I have will not cock past where the self timer button would have been. There Is a little plate in the way that is just inside the outer housing but still just visible from outside the shutter.

    It would be great if this variant doesn't original have the button since all functions of the shutter appear to work perfectly otherwise. Times even down to 1 sec sound good.

    Thanks again.
  7. All leaf shutters operate from 1 second to 1/125 (1/100) from the main setting (cocking) spring tension and delay timer mechanism. Above 1/125 a booster spring is employed with the delay timer locked out. Compur shutter use a delay mechanism similar to a watch.
    With the shutter set to 1 second cock the shutter, position the shutter so you can see the shutter blades and the second hand of a clock or watch (sweep second hand works best). When the second hand reaches a second mark trip the shutter, the shutter should open completely and close just as the second hand reaches the next second mark. The second hand width (narrow style) either side of the next second mark is in tolerance.
    Set the shutter to 1/2 second and repeat. The shutter should open fully then close just as the second hand reaches the mid point between the starting and next second mark, tolerance is 1/2 the width of the second hand. Increase the shutter speed to the next speed and verify it runs faster as you go up in speed, slower as you decrease the speed.
    If these two speeds are off all others will likely be also.
    Buried in the archives of this site are the instructions for building a shutter speed tester, inexpensive and accurate.
  8. As long as the shutter runs normally, I wouldn't worry about it Chris.

    As thirteenthumbs says, these old shutters often have stuttery or sticking S-T mechanisms anyway. So you're probably better off without the S-T facility.
  9. Thanks thirtennthumbs and rodeo_joe for the information.

Share This Page