I bought this cassette the other day. I do not manage to get more than 8 frames out of one roll. Space between frames is variable from 1cm to 1 inch. The first three frames are adequate, after that the space between frames gets larger and larger, as though it would be a 6*9 cassette. Am I doing something wrong or is t his cassette not functioning well? I always transport the film to the next frame by turning the handle a full 180 degrees. If I do not the counter jumps to the next frame-number before the film has been transported enough for a 6*7 frame, s o I would get overlap of frames.