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  1. #11
    rjbuzzclick's Avatar
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    Quote Originally Posted by Dan Daniel View Post
    http://people.rit.edu/andpph/text-slit-scan.html
    About a 'page or so down is a small thumbnail of the right side of a couple dancing. Robert Doisneau, an extra twist...
    I tried this myself with a Pacemaker Speed Graphic and this is the best that I got. Check out the position of her feet. I "hand-wound" the shutter slowly using the 1/1000 slit while she was turning on the merry-go-round rather quickly (she was a good sport!). The banding is from the uneven travel speed of the FP shutter slit.:
    Last edited by rjbuzzclick; 03-15-2012 at 07:50 PM. Click to view previous post history.
    Reid

    http://www.flickr.com/photos/rjbuzzclick/

    "If I had a nickel for every time I had to replace a camera battery, I'd be able to get the #@%&$ battery cover off!" -Me

  2. #12
    John Austin's Avatar
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    Quote Originally Posted by jnanian View Post
    it really can't be done with a speed graphic because 1/30 is too fast for that sort of distortion
    i have done it ( barely ) with a graflex slr, and a shutter at around 1/15S and a moving bus ( /barely )
    but never at a sports event
    John,
    My SG shutter goes down to 1/10th second - However, I make an assumption that the smallest slit should be set with the slowest tension - (Aperture D with Tension 1 = 1/500th sec) I have found the SG shutter to be fairly accurate

    I will take it to town today and try - Results to follow, though I really need a big road, which could we weeks away

    Click image for larger version. 

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    Anyway, I feel this is the only one way to find out
    Last edited by John Austin; 03-15-2012 at 06:48 PM. Click to view previous post history.

  3. #13

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    Quote Originally Posted by Grumpy Old Man View Post
    John,
    My SG shutter goes down to 1/10th second - However, I make an assumption that the smallest slit should be set with the slowest tension - (Aperture D with Tension 1 = 1/500th sec) I have found the SG shutter to be fairly accurate

    I will take it to town today and try - Results to follow, though I really need a big road, which could we weeks away

    Click image for larger version. 

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    Anyway, I feel this is the only one way to find out

    too cool, you must have a "anniversary" .. i'm short-sighted and forgot
    that the older models had like 25 speeds ( i wish mine had 24 of'em ! )
    my pacemaker only goes to 1/30 ( only has 6 speeds )

    have fun "Jacques Henri"

    john

  4. #14
    Leigh B's Avatar
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    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
    “Wise men talk because they have something to say; fools, because they have to say something.” - Plato

  5. #15
    rjbuzzclick's Avatar
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    Correct, you need a thin slit traveling at a slow speed. In my example in post #11, I was trying to reproduce the effect seen in Rober Doisneau's photo of the man and woman twisted around each other. If you look closely at her feet, and follow the line of her legs, you'll see that they're twisted oddly. It's not as great of an effect as I would have liked to get, but it's close. At some point I'll try this again and hopefully have better luck. I was using the 1/1000 slit, but "hand winding" it so it traveled across the film in about two to three seconds.

    I ran other tests using the different FP shutter speeds on my Pacemaker SG and was able to get some bending on the upright poles of the merry-go-round with smaller slit openings, but no twisting of my model as in Robert Doisneau's photo.
    Reid

    http://www.flickr.com/photos/rjbuzzclick/

    "If I had a nickel for every time I had to replace a camera battery, I'd be able to get the #@%&$ battery cover off!" -Me

  6. #16
    Leigh B's Avatar
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    It's funny...

    I was shooting sports with a Speed Graphic in the early 1960s and tried very hard to __avoid__ this kind of distortion.

    Times change.

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

  7. #17
    rjbuzzclick's Avatar
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    Quote Originally Posted by Leigh B View Post
    It's funny...

    I was shooting sports with a Speed Graphic in the early 1960s and tried very hard to __avoid__ this kind of distortion.

    Times change.

    - Leigh
    Damn kids these days! Hey, get off my lawn!
    Reid

    http://www.flickr.com/photos/rjbuzzclick/

    "If I had a nickel for every time I had to replace a camera battery, I'd be able to get the #@%&$ battery cover off!" -Me

  8. #18
    RalphLambrecht's Avatar
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    i thought, yhis image was an example of horizontal shutter distortion with fast-moving subjects, which is different to focal-plane distortion.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  9. #19
    Leigh B'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.
    Nope. Horizontal distortion stretches the subject width without distorting vertical lines.

    Think of a narrow slit moving across the film. Lines parallel to the slit will not be distorted.
    Lines perpendicular to the slit will exhibit distortion, the specifics of which depend on the direction of subject and shutter movement.

    As a shutter slit moves across the film, different areas of the film capture different points in time,
    i.e. the 1/500th sec at the top of the film is not the same time as the 1/500th sec at the bottom.

    - Leigh
    Last edited by Leigh B; 03-20-2012 at 02:50 AM. Click to view previous post history.
    “Wise men talk because they have something to say; fools, because they have to say something.” - Plato

  10. #20
    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

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