I think you need to do a little geometry and you'll see this is much less a problem than you think. The line from the edge of the film to the apex of the lens will only be impinged with an extremely large amount of shift. More than your lens is likely to cover as other posters have suggested.
-----Original Message----- From: Steve Goldstein [mailto:[EMAIL PROTECTED]] Sent: Tuesday, November 13, 2001 4:05 PM To: [EMAIL PROTECTED] Subject: Re: [Cameramakers] Movements vs. back dimensions for a field camera Wayde, Thanks for your thoughts, and sorry if I wasn't more clear. I'll try to (briefly) explain a little better and attach some numbers. Let's build a camera with a 9.5" box (exterior dimensions) for 5x7 film. If the box walls are 1/4" this leaves 9" for the internal dimension, or 1" allowance on each side. Assuming the bellows mounts to the front of the box somehow, the interior edge of the opening here will probably be somewhat less than this, let's say 1/2" from the external edge. So the opening at the front of the box is now 8.5", or 0.75" beyond the film dimension on the long side. So assuming a perfect bellows which never gets in the way, it seems to me that the front opening will ultimately limit the amount of relative shift between the front and rear - at some point the bellows frame will start blocking light, thus imposing the primary limit on movements. It occurs to me in typing this that a possible solution is to arrange that the bellows mounts towards the rear of the box, perhaps even at the film plane. In this case the problem is lessened - now the front edge of the box will eventually hit the bellows and block the inbound light, but this happens later than in my originally-assumed case. Is this how it's normally done, i.e. mount the bellows closer to the back and not the front? In the case of a removable bellows it seems one would then have to remove the back to change the bellows. Maybe this isn't a big penalty since swapping bellows is done far less frequently than changing film, or even lenses... Thanks for the forum. steve _______________________________________________ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers _______________________________________________ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
