Auteur: Dan Fromm
Date: 22-06-2005 13:23
Emmanuel, for me its very simple.
I shoot 2x3, not a very large format. And my little Graphics have minimal movements. So mounting lenses in barrel in front of a Copal #1 is, for me, quite practical. In my situation, mechanical vignetting by the shutter is not a bad problem. For formats larger than 2x3, front mounting, especially on a small shutter like the Copal #1, can be impractical because of vignetting by the shutter.
Front-mounting lets me have timed speeds from 1/1 to 1/15 -- my Speed Graphic's slowest timed speed is 1/30 -- , a "B" that closes quickly, and allows electronic flash at 1/400. This last is very useful for closeup work out-of-doors with ISO 100 films.
When I need to use a lens in barrel that can't be front-mounted, usually because of short back focus, or when I need 1/1000, the Speed's focal plane shutter is there. I can't speak for others, but my Speed's FPS is in good working order and has been very reliable. I have, though, seen Speed Graphics whose FPS ran very slowly, reluctantly, even, at all speeds. These needed service.
Note that the Speed Graphic uses the most primitive possible focal plane shutter, with slits of fixed width. There's no possibility of the gap between front and rear curtain changing while the shutter is running. The rate at which the curtain travels may change while the shutter runs, but that's another problem.
You're right that there's no possibility of using electronic flash with the Speed's FPS. Chemical flash is another matter.
Regards,
Dan
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