At 05:27 23.10.01 +0000, you wrote: >Why not just put a glass about a centimeter in front of the film. Dust on >this glass will make a very diffuse shadow except possibly at very small >diaphragm openings, so you are unlikely to notice it. Conversely, the >volume to be pumped is smaller than when you pump the bellows and the >notmal swings and tilts have no influence on the pressure, or vice versa.
You also eliminate scratching of the glass with this scheme. Continuous pumping is fully practical in a stationary setting and is probably standard for the larger formats for repro work and various precision operations like photoetching, where exact flatness is needed and the film is rather large to support only at the edges, anyway. In the usual studio being connected to a pump could be awkward, but if the back design is good I suspect the extra trouble will be hardly disturbing. Bob >Yes, I understand all this and that's the reason why I'm using the rubber >strips to seal just the area around the film opening in the the front (lens >side) of the back instead of the entire back. > >While some degree of air will always leak out of the pressurized bellows, >the amount that leaks out right now is larger than I'd like since it >requires pumping air into the bellows continously in order to make my setup >work. While this is minimally practical in a studio environment, it's >totally impractical in the field. I know the bellows will need to be >relieved of some pressure between shots in order to allow for focusing and >movements but having to pump it up each time from empty is more work than >I'm willing to undertake, especially with the small rubber bulb I'm hoping >to use. > > >Jeff Goggin >Scottsdale, AZ >_______________________________________________ >Cameramakers mailing list >[EMAIL PROTECTED] >http://rmp.opusis.com/mailman/listinfo/cameramakers _______________________________________________ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
