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  1. #21
    Ian Grant's Avatar
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    Quote Originally Posted by RalphLambrecht View Post
    i thought, yhis image was an example of horizontal shutter distortion with fast-moving subjects, which is different to focal-plane distortion.
    It depends on what you mean by Horizontal and vertical. These older Focal plane shutters tended to have blinds that had a horizontal slit that moved vertically for the exposure, like modern Seiko SLRshutters. Older SLR's tended to use cloth shutters with a vertical slit that moved horizontally.

    When governed by tension and slit width like on a 5x4 Speed Graphic a horizontal edge of the shutter curtain slit takes just over 1/10th of a second to cross the film plane at the minimum tension #1, yet with the narrowest slit width this gives a shutter speed of 1/350th. So there's a time lag of 1/10th between the exposure at the top and at the botton, slightly longer if a wider slit is used.

    Even at the top speed of 1/1000 which is at the maximum tension #6 there's a lag of 1/35th of a second.

    Ian

  2. #22
    Schlapp's Avatar
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    http://www.flickr.com/photos/schlapp/2833892718/

    Using a auxiliary shutter [slot in cardboard in front of lens]. My partner walking .

  3. #23
    Sirius Glass's Avatar
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    Quote Originally Posted by Leigh B View Post
    Hi Sirius,

    Your shutter speed is too slow. Go back and read my post #4.

    You must use a shutter speed fast enough that the shutter aperture is a moving slit.

    - Leigh
    I tried 1/30s, 1/25s, 1/20s, 1/15s, and 1/10s multiple times slowly panning cars move 50mph perpendicular to me at about 40 feet away using a 7 1/2" lens.
    Warning!! Handling a Hasselblad can be harmful to your financial well being!

    Nothing beats a great piece of glass!

    I leave the digital work for the urologists and proctologists.

  4. #24
    Newt_on_Swings's Avatar
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    Moving roll film would work as well. I asked about this a bit back as well. I'll post the link for the old post when I can find it later.

  5. #25
    Leigh B's Avatar
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    Quote Originally Posted by Sirius Glass View Post
    I tried 1/30s, 1/25s, 1/20s, 1/15s, and 1/10s multiple times slowly panning cars move 50mph perpendicular to me
    Hi Sirius,

    Like I said... Your shutter speeds are too slow.

    To get the "sliding" effect you need a narrow slit moving across the film.

    At the speeds you listed I believe the SG focal plane shutter is completely open, which will not deliver the desired result.

    - Leigh
    “Wise men talk because they have something to say; fools, because they have to say something.” - Plato

  6. #26
    Newt_on_Swings's Avatar
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    http://www.apug.org/forums/forum42/8...an-camera.html

    I will have to revisit it again soon as the weather is nice now, I never really got the chance to do it, and when I did set it up, I didn't have a target I could get to easily to experiment with. Plus I think a motor for rewinding would provide a better/steadier flow than hand winding.

  7. #27
    Sirius Glass's Avatar
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    Quote Originally Posted by Leigh B View Post
    Hi Sirius,

    Like I said... Your shutter speeds are too slow.

    To get the "sliding" effect you need a narrow slit moving across the film.

    At the speeds you listed I believe the SG focal plane shutter is completely open, which will not deliver the desired result.

    - Leigh
    Thanks, I will try it again with a smaller slit. I guess that I had bad advice before.
    Warning!! Handling a Hasselblad can be harmful to your financial well being!

    Nothing beats a great piece of glass!

    I leave the digital work for the urologists and proctologists.

  8. #28

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    Quote Originally Posted by Sirius Glass View Post
    Thanks, I will try it again with a smaller slit. I guess that I had bad advice before.
    i did mine at 1/15 of a second .. (the one posted) ..
    i have done more than once ...
    perhaps both advisements are correct ... ?

  9. #29
    Sirius Glass's Avatar
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    So if I use 400 speed film, and shoot at tension 1 and 1/8" slit [1/350] @ f/16 and my 15" lens rather than the 7.5" lens, it should work!
    Warning!! Handling a Hasselblad can be harmful to your financial well being!

    Nothing beats a great piece of glass!

    I leave the digital work for the urologists and proctologists.

  10. #30
    Ian Grant's Avatar
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    Quote Originally Posted by Sirius Glass View Post
    So if I use 400 speed film, and shoot at tension 1 and 1/8" slit [1/350] @ f/16 and my 15" lens rather than the 7.5" lens, it should work!
    Ideally you need a vintage racing car as well with spokes, and this the oldest motor racing track in the world is the ideal place to do it

    Ian

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