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Thread: Giant shutter?

  1. #11
    jp's Avatar
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    Re: Giant shutter?

    Quote Originally Posted by Old-N-Feeble View Post
    Some folks gut an old 4x5 Speed Graphic for the focal plane shutter... speeds from 1 sec to 1/1000 plus T. But that's 4x5, not 5x5.
    It's really a little more like 4.5x5. There is some extra travel that is masked by the 4x5 back. It could be potentially the same shutter as used by an RB graflex SLR, which would do 5x5 because it's revolving back. In that case, one would have to be a better woodworker than I to get 5x5 out of it.

    http://www.f64.nu/photo/tmp/lff/_DSC7351s.JPG http://www.f64.nu/photo/tmp/lff/_DSC7350s.JPG is the speed graphic focal plane shutter setup I use for a ~~4.5" rear element lens.

    I don't know if this is close enough to the OP's goals. Another option would be a set of ND filters to allow more exposure flexibility with a guillotine or packard shutter.

    If it's a homemade camera and the purpose of the lens is to shoot wide open, you better make it very solid at the front as any flexing will throw it out of focus at such a thin DOF.

  2. #12
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    Re: Giant shutter?

    Quote Originally Posted by Dan Fromm View Post
    The big idea here, OP, is that the shutter doesn't have to be as large as the lens' maximum aperture or the exit pupil if it is close to the lens. Don't scoff, try it.
    Actually what you're saying Dan is similar to some pre-WWII lens hoods which had a plate at the front with a rectangular cut-out, Some Cine and Video lens hoods still use this system.

    So a 5x4 Speed Graphic shutter should be fine.

    Ian
    Attached Thumbnails Attached Thumbnails lenshood.jpg  

  3. #13

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    Re: Giant shutter?

    Quote Originally Posted by IanG View Post
    Depending on the lens size one of the larger standard Thornton Pickard roller blind shutter (or similar) may be OK, I have a couple that would work with a 120mm diameter front/rear diameter lens. While these are usually 1/15th to a 1/90 there were higher speed versions - essentially they just need a narrower slit - would need to be front mounted in this case but 1/400th is possible. These do come up for sale occasionally or I get mine from camera fairs etc. I restored 3 larger ones last Spring.

    If you found a Focal plane version with all its brass work then restoration is relatively easy. TP also made 10x8 cameras with built in FP shutters.

    Ian
    Thanks, will keep in mind.


    Quote Originally Posted by jp498 View Post
    It's really a little more like 4.5x5. There is some extra travel that is masked by the 4x5 back. It could be potentially the same shutter as used by an RB graflex SLR, which would do 5x5 because it's revolving back. In that case, one would have to be a better woodworker than I to get 5x5 out of it.

    http://www.f64.nu/photo/tmp/lff/_DSC7351s.JPG http://www.f64.nu/photo/tmp/lff/_DSC7350s.JPG is the speed graphic focal plane shutter setup I use for a ~~4.5" rear element lens.

    I don't know if this is close enough to the OP's goals. Another option would be a set of ND filters to allow more exposure flexibility with a guillotine or packard shutter.

    If it's a homemade camera and the purpose of the lens is to shoot wide open, you better make it very solid at the front as any flexing will throw it out of focus at such a thin DOF.
    Thanks for the pointers. Yes, the bulk introduces more problems usually.


    Quote Originally Posted by Dan Fromm View Post
    Hmm. 300 mm lens, 300 mm circle, 1/500. Hmm. According to a stupid little similar triangles model that I use to help me think about front-mounting, that can almost be done with a #1 close behind the lens.

    A Compur/Copal/Prontor 1's maximum opening is 30 mm, lens' rear node-to-infinity is 300 mm, the circle covered is 300 mm. If the rear node-to-shutter distance is no more than 30 mm the shutter will vignette the circle to no less than 300 mm.

    If you think hard about my little model you'll see that it isn't quite right. That said, I've shot a 480 Apo Nikkor on my tandem 2x3 Graphic with no vignetting. Filled the 2x3 frame with good image, corners weren't darker than the center.

    There's a minor(?) snag with this approach when applied to lenses with large apertures. Basically the lens' diaphragm will have no effect on exposure -- the lens will effectively be at full aperture -- until the exit pupil is the size of the shutter's maximum opening.

    The big idea here, OP, is that the shutter doesn't have to be as large as the lens' maximum aperture or the exit pupil if it is close to the lens. Don't scoff, try it.

    Quote Originally Posted by IanG View Post
    Actually what you're saying Dan is similar to some pre-WWII lens hoods which had a plate at the front with a rectangular cut-out, Some Cine and Video lens hoods still use this system.

    So a 5x4 Speed Graphic shutter should be fine.

    Ian
    Very interesting suggestion, Dan and thanks for clearing it up, Ian. I might try just that. My only reservation is though, the 4x5 Speed Graphics are pretty thick. Guess I'll have to hack it up a bit to know either way. If luck's on my side, it'll double as a lens hood too!


    Thanks to everyone for the responses.

  4. #14

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    Re: Giant shutter?

    So here's the update... putting the 4x5 Speed Graphic in front will indeed change the image. For things to not make a difference when the front element is partially obstructed (e.g. like with a front baffle), I imagine the image circle needs to be much larger than the film plane... and with my lens it's not.

    Next step would be to try the same from the rear.

  5. #15
    indecent exposure cosmicexplosion's Avatar
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    Re: Giant shutter?

    Jello mr type righter
    The guy I bought my ektar off of, used a seed graphic, I discovered on inquiry after reading this Fred.
    Only he used a ploubel 8 10 that has a 9x9 lens board.
    I believe he put it behind the lens to great effect.
    I can send the pic he sent me if you are intensely interested.
    But abreast I would like to kept of your developments
    And more importantly I would like to see some images made with one as I have only seen one.
    Do you know of any images any where?
    Cheers
    Andrew
    through a glass darkly...

  6. #16
    Drew Bedo's Avatar
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    Re: Giant shutter?

    What about the focal plane shutter from one of the Graqflex Reflex cameras" The RB series could shoot 4x5 in either landscape or portrate . . .the shutter must have been larger.

    they made them in 5x7 as well . . .even bigger.

    Make sure the doner body is a junker though.
    Drew Bedo
    http://www.artsyhome.com/author/drew-bedo




    There are only three types of mounting flanges; too big, too small and wrong thread!

  7. #17
    indecent exposure cosmicexplosion's Avatar
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    Re: Giant shutter?

    yeah i am in a bit of a fix as to what to do with this massive lens, it seems like i have to spend another grand just getting the ploubel 8x10 to be able to use it, good side, comes with working shutter, all rigged up.

    i forgot to ask mr typewriter, what body are you using?
    through a glass darkly...

  8. #18

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    Re: Giant shutter?

    What about making a series of gravity drop shutters with various sizes of slots?

  9. #19

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    Re: Giant shutter?

    It's going to be tough to find a 5x7 Graflex focal plane shutter in good condition. I have a 5x7 Speed Graphic where the body is in great condition but the shutter cloth looks like it could explode at any moment (still light tight and works though). From what I've read this is a common affliction for these older shutters and there are few repairmen who know how to replace them.

  10. #20

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    Re: Giant shutter?

    The East German "Mentor" cameras might be possible donors. Check them on German ebay, there are two monorail models 13x18cm and 18x24cm with a shutter mounted behind the lens, which was up to 300mm f4,5, and a 13x18cm folding model with a shutter in front of the film holder. Unfortunately, I do not have any personal experience with either. They seem rather primitive, but this might be an advantage in your case, and they come up fairly regularly.

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