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[Doug Kerr]

As I understand it, the word "Speed" in the name "Speed Graphic" was meant to celebrate the fact that the focal plane shutter of the Speed Graphic offered speeds up to 1/1000 sec, a speed not practically available with lens-associated shutters at the time.

But that shutter speed didn't really make the camera suitable for "action" phtography owing to the image skew with moving subjects (the "leaning schoolbus" phenomenon) resulting from the operation of the FPS.

So perhaps the advantage of such a short shutter speed would be in getting proper exposure with a bright scene and/or a large aperture.

But it would seem that with the modest apertures usually provided on lenses used on the Speed Graphic, and the modest film "speed" available at the time, there wouldn't be much need for that, either.

So, what was the big deal about the 1/1000 sec shutter speed?


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Best regards,

Doug


[ This Message was edited by: Doug Kerr on 2007-03-21 09:57 ]

[Les]

Your first reason is the right one, The Speed Graphic was meant for action photography, not only was it much smaller and lighter than reflex cameras of the age, but it had a 1/1000th of a second capability.

The Lartigue effect can be done on some of the Speed Graphic cameras but you need know how. You want the smallest slit with the lowest tension. This makes the shutter travel time long enough to have an effect. While Lartigue didn't use an Speed Graphic, the best tension/aperture combination gives an effective exposure of around a1/170th to 1/500th of a second depending on the model Speed. I don't think the 1/500th will give the distortion myself, but I guess it depends on the velocity of the subject.

The second benefit of the focal plane shutter that Mr. Folmer invented was that it gave much more even exposure over the film than other focal plane shutters and suppsedly aperture shutters. At the time of introduction, nearly all focal plane shutters used two curtains. Depending on the design, they either overexposed the second half or underexposed it as keeping those curtains the same distance throught the exposure was difficult. By tieing the two curtains together, Mr. Folmer eliminated the problem and simplified the construction.

[troublemaker]

True Doug. To shoot f~4.7 and 5.6 lenses wide open in sunlight it is nice to have the extra speed at ISO 50 or 100. Just can't do it with leaf shutters opeprating at a max 1/200. The FPS IMHO is also consistently more accurate than a leaf shutter, and also allows thefilm to record the best possible image from the lens as it moves past, not so with a leaf shutter opperating at faster speeds. I think the advantage goes back to the front leaf shutter as the speeds slow down.

[Doug Kerr]

Thanks, guys.

Doug