I must be missing something. I have some film holders but haven't used them yet (no camera yet!).
I don't see a moveable/adjustable pressure plate. I see a hinged access part that opens after removal of the darkslide, then metal guides that the film slides into, and a depression for a thumbnail to extract the film. There are little levers that rotate to 'lock' the darkslide in place. I'm told they also serve a purpose for keeping mental note of which side of the film holder has been exposed. Do they serve a second (third?) function of applying pressure on the film? I thought the film holder basically just holds the film from curling up, and with very large format, the film can bow away from the back of the film holder. >From what I've read, apparently some early aerial cameras did not have vacuum to hold the film, and the film did lift away from the platen (back of their film holder). A guy told me that they would then only shoot during a declines to 'push' the film flat against the platen, and that was why vacuum was added...so they could shoot at any inclination. Another guy gave me an interesting explanation from his father who flew a plane with a camera, about the nighttime cameras with the f/2.5 Aero-Ektar lens and 'flash bombs'. They dropped a 50 pound flash bomb containing 25 pounds of flash powder, set to ignite at various altitudes. The camera had a photocell of sorts to detect the flash and trigger the shutter. The flashbomb was on the order of 2 million candlepower. Having no practical perspective for this, I inquired if this was noticeable to the subjects being photographed. He said it sure as %@#%^ did - it illuminated the ground to mid-day brightness - they'd shoot maybe 6 shots (on a 3 second or so cycle) and scramble out of there as fast as they could. A former-photographer neighbor has a 16" x 20" camera in storage - I'm thinking of asking him if I can take measurements on the film holder, but I will have to rely on a tape measure for the height and width - I don't have a caliper that huge. Murray _______________________________________________ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
