<p>Ok I need help.<br />I just purchased a used Mamiya RB67 Pro with a Sekor C 127mm lens on ebay. The guy said everything works and he his right. When I remove the lens and fire the camera, the mirror goes up normally and everything is fine. When I take the lens alone, all the shutter speed work, etc. But when I put the lens on the body, without mirror lock-up, and fire, the shutter do something weird and the mirror only goes up about 1/4 on an inch. Even in mirror lock-up it does that. Please I need help I don't know what to do.</p>