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Thread: Help with stuck Copal 0

  1. #1
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    Help with stuck Copal 0

    I have a Copal 0 shutter that appears to be stuck:

    1. Shutter is cocked (loose lever as when loaded)
    2. Preview is closed
    3. Release pulls back, but the shutter does not release

    Any ideas or is it going in for service?

    Thanks for any tips...

  2. #2
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    Re: Help with stuck Copal 0

    Sounds like a service to me, sorry!

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    Re: Help with stuck Copal 0

    Try different shutter speed...

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    Re: Help with stuck Copal 0

    Thanks guys. Did try a couple of other speeds, but when the shutter is cocked, turning the dial is not the best idea AFAIK. In any case, did not help.

    I'm just going to swap the shutter with one of the lenses I use less frequently and send it in for service.

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    Re: Help with stuck Copal 0

    If you're going to be in NYC for the show we have a guy that can do it same-day in the city.
    Doug Peterson , Digital Transitions | Email
    Dealer for: Phase One, Mamiya Leaf, Arca-Swiss, Cambo, Eizo, Profoto
    Office: 877.367.8537. Cell: 740.707.2183

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    Re: Help with stuck Copal 0

    Thanks Doug. I'm there at a different conference next week, and may pop into the photo show (registered to get a break from my show. I'll definitely bring it down. That saves me a lot of trouble. Thanks again, jag.

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    Re: Help with stuck Copal 0

    Quote Originally Posted by jagsiva View Post
    I'm just going to swap the shutter with one of the lenses I use less frequently and send it in for service.
    Unless the two lenses are almost identical (focal length and max aperture), the aperture scale will not be correct.

    - Leigh

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    Re: Help with stuck Copal 0

    Quote Originally Posted by Leigh View Post
    Unless the two lenses are almost identical (focal length and max aperture), the aperture scale will not be correct.

    - Leigh
    I had no idea, thanks. I thought the shutters were the same, and the lens manufactures just added shims during calibration.

    Looks like I should be able to get it fixed quickly in any case.

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    Re: Help with stuck Copal 0

    (The following is somewhat simplified, but the concept is correct.)

    A lens aperture is normally shown as f/n or f:n, where n is the numeric aperture (1.4, 2, 2.8, 4, 5.6, etc).

    That is actually a fraction that defines the diameter of the aperture in the shutter.

    For a 100mm lens at f/2, the aperture is 100 / 2 = 50mm in diameter.
    For a 200mm lens at f/2, the aperture is 200 / 2 = 100mm in diameter, etc.

    There are other factors not mentioned in this simplified discussion that will affect the aperture.
    Two lenses of identical focal length but different design may have different aperture diameters.

    - Leigh

    Quote Originally Posted by jagsiva View Post
    I had no idea, thanks. I thought the shutters were the same, and the lens manufactures just added shims during calibration.

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    Re: Help with stuck Copal 0

    As I understand it, you can swap a Copol 0 between between any tech lens, as long as the lens was originally designed for a Copol 0 shutter. The lenses don't have a aperture scale, and no internal focus. Focus is done with the helical.

    If you replace a shutter, it does have to be re-collimated to be exact. This is done by the lens company, Schneider or Rodenstock. I had a lens that went back to Arca, but they determined the problem was not the shutter, so it did not have to go back to Rodenstock. When Schneider and Rodenstock manufacture the the new lenses, they do the collimation of the shutter.

    Precision Camera in IL, can also work on Copols, i.e. stuck or jammed. I have a 28 HR that is going to them as soon as the fall color season is over as it's Copol is starting to get stuck, but so far has eventually released.

    Eventually as existing Copols fail, I guess we all have to move to some form of electronic shutter as the Copol 0 and 1 are no longer made.

    Paul

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    Re: Help with stuck Copal 0

    Thanks Paul, that's kind of how I understood it as well. Funny enough, the lens that has an issue for me is the 28HR.

    The aperture opens far bigger than the lens opening, so I would think the same Copal 0 Shutter is used in every lens. Now, I do know the lens manufactures put shims in based on their calibration. Then guys like Arca, if using a helical mount of some sort, furthe calibrate with custom plates and spacers.

    I'm going to take it to NYC next week and get it fixed as Doug suggested.

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