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  1. #11
    127
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    Quote Originally Posted by egdinger
    Is a focal plane shutter nessacery to achive this effect, or would a shutter in front of the lens the uses a slit cause the same thing? I have an idea for a shutter that I have been toying with and it may work for whay AZLF wants to achive, assuming it works at all.
    You need a focal plane shutter to get the full effect. A shutter next to the film exposes each part of the film seperatly, while a shutter at or near the lens is so out of focus, that it exposes the whole film at once, but with different light paths through the lens being used over time.

    If the shutter is some place else then you'll get some combination of the two effects - the whole film will be exposed for the whole time, but with different emphasis, so while the whole film IS exposed, at the begining the of the shutter time the bottom of the film is exposed more while the top receives more light at the end of the shot.

    This effect should look nice - it's a form of shutter efficiency, and in the simulations I've done, low efficiency shutters produce better images. However I suspect the geometry involved will mean that to get an effect other than that of a conventional leaf shutter the falling plate would need to be a LONG way infront of the lens (totally inpractical) or some way behind the lens (say 3/4 of the way back in the camera).

    Ian

  2. #12
    David A. Goldfarb's Avatar
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    J-H Lartigue was probably using a 5x7/13x18 camera like my 5x7" Press Graflex in his famous race car photo. Travel time on this shutter depends on the spring tension, which is set separately from the slit size, and a table is used to calculate the effective shutter speed, but it could be as slow as 1/5 sec. The slower the travel time, the stronger the effect. With an 1/8" slit and maximum tension, by the way, this shutter can have an effective shutter speed of 1/1500 sec.

    [Edit--Misinformation deleted, corrected below].
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
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  3. #13
    KenM's Avatar
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    For another demonstration of a similar kind of distortion caused by mounting a scanner on a large format camera (!), check out this site.

    It's the only time you'll see an Audi TT stretch limo
    Cheers!

    -klm.

  4. #14
    David H. Bebbington's Avatar
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    As the basic for experimentation in trying to get extreme distortion, I would think this item would be great:
    http://cgi.ebay.co.uk/UNUSUAL-GRAFLE...QQcmdZViewItem

  5. #15
    127
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    If anyone has access to online journals (or a library even!) you could check out:

    Glassner, A 1999. "An open and shut case", IEEE Computer Graphics and Applictions 19,3 (may).

    It's a pretty interesting read. HOWEVER Andrew demonstrates the great folloy of the scientist - he's never actually seen some of the things he's talking about, so when he talks about the geometry of leaf shutters its TOTALLY WRONG!. The rest of the paper is worth the read though.

    Ian

  6. #16
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    Quote Originally Posted by David H. Bebbington
    It's actually a vertical focal-plane shutter. If you imagine a car traveling from left to right, and that you are photographing it holding the camera still without panning, this means its image will be upside down and traveling from right to left. As the focal-plane shutter of a camera like a Speed Graphic travels downwards, it will expose the top of the image (bottom of the subject) first and the bottom of the image last. With a moving subject, the bottom of the image will therefore be recorded later and shifted to the left relative to the top, thus giving a "leaning" effect and oval wheels. This happens because the shutter of a 4x5" press camera is so big. The same thing happens in theory with the focal-plane shutter of a 35 mm camera, but because this is small, has low mass and can be made to accelerate and travel so quickly, the distortion effect is virtually non-existent.

    Regards,

    David
    When shooting a race car with a horizontal moving shutter in a stationary camera, the car will be compressed or expanded laterally, depending on which way the shutter and car are moving. With a vertically moving shutter it will appear to lean. If the camera is panned, the background will lean. To duplicate the leaning effect with today's cameras, the shutter must move perpendicular to the subject's movement. A downward moving shutter will make the subject lean forward; an upward moving shutter will make it lean back. The effect can be enhanced by panning against the subject's movement.

  7. #17
    David H. Bebbington's Avatar
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    Quote Originally Posted by Jim Jones
    When shooting a race car with a horizontal moving shutter in a stationary camera, the car will be compressed or expanded laterally, depending on which way the shutter and car are moving. With a vertically moving shutter it will appear to lean. If the camera is panned, the background will lean. To duplicate the leaning effect with today's cameras, the shutter must move perpendicular to the subject's movement. A downward moving shutter will make the subject lean forward; an upward moving shutter will make it lean back. The effect can be enhanced by panning against the subject's movement.
    Absolutely, which is why (I presume), after some initial dalliance with upward-moving shutters like David A. Goldfarb's Press Graflex, makers decided to make their shutters move downwards, on the grounds that if you're going to have distortion, leaning forward looks more pleasing and suggests speed better. Generations of cartoon and animation artists have agreed!

  8. #18
    David A. Goldfarb's Avatar
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    Correction--I think shooting LF makes it so I can't tell up from down anymore. I should have double checked the camera before posting, as indeed, the Press Graflex shutter moves downward rather than upward, so the beginning of the exposure is the top of the frame or the bottom of the picture. In the Lartigue photo the wheel leans forward, because the car is moving faster than the shutter, and the spectators lean backward, because the young Mr. Lartigue is panning.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
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  9. #19
    Ole
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    ... but I believe the young M. Lartigue used a Goerz camera, not a Graflex...
    -- Ole Tjugen, Luddite Elitist
    Norway

  10. #20
    David A. Goldfarb's Avatar
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    Could have been. I've been trying to find out. Did Goerz make a FP shutter camera? The 5x7" Press Graflex was a pretty common camera at the time among photojournalists. Lartigue's father had some sort of 13x18 camera, which J-H used, but I gather that the family was wealthy, and he had access to various cameras.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

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