Camera Parts: Film Rewind
One of the camera parts on film cameras that are older is the film rewind knob or lever. Newer cameras have replaced this with a motorized system that takes care of film rewinding. However, on a manual camera, this is a very important part to ensure proper operation.
Purposes of Film Rewind Knobs
There are two purposes for this feature. First, once a roll of film is complete, these allows a photographer to rewind the film back into the film cassette. Then the film can be safely removed and delivered for processing. To do this, a lever is flipped out of the knob. Using the lever, the knob is spun, usually clockwise, and the film is rewound. It is often necessary to press a film rewind release button to unlock the winding sprockets and allow rewinding.
The second purpose of a film rewind knob is to ensure proper loading. As the winding sprockets pull film onto the take-up spool, the film rewind knob will spin, indicating that film is being pulled. If it does not spin, then film is not being advanced. This indicated a problems with the take-up spool, the sprockets, or the gearing attached to the film advance lever. If film is not being advanced, the camera will not take pictures properly.