The issues below are my findings as well. At first I didn't know what caused my film flatness problems except that it happened in cold weather. My camera back has been at service a couple of times and the last time everything was tightened up. If anything, this made the problem slightly worse. Last summer I shot a roll over two days. All the frames were sharp except the second frame of the second day; ie. the piece of film that spent the night bent backwards over the rollers. Indeed if you shot one frame at the time in cold weather with a 645 camera the solution is to shoot only every second frame; ie. frame 1, 3, 5 etc. In this way, the exposed frame has never spent time bent over the rolls.
P�l >2. >Film flatness problems are mainly caused by the combined influence of >two factors: the rollers in the camera or magazine that bend the film, >and the time a certain part of the film is bent by such a roller. > >Camera manufacturers usually space the rollers in a way that bent >portions of the film will never be positioned near the center of the >image. Therefore only marginal regions of the image should be affected >by sharpness problems due to film flatness errors. > >Since the photographer cannot alter the geometry and mechanics of his >camera, he can only influence the other factor: time. A film run >through the camera without much time between exposures should result >in good flatness and hence sharpness. Five minutes between exposures >may be some sort of limit, depending on brand and type of film. 15 >minutes are likely to show an influence of bending around rollers. Two >hours definitively will. - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
