Photographic film cassette

A radial bar code providing DX film information is disposed on a disc mounted at an axial end of a film cassette, the disc being rotatable with rotation of the film spool during film extraction and rewind. Film exposure status visual indicators are disposed on the disc. A stationary optical reader in the camera in association with a logic and control circuit can thus read the DX information from the rotating disc during film extraction for suitable control of exposure conditions in the camera. During film rewind the angular positioning of the disc can be measured from the bar code to cause the disc to be stopped at the end of rewind with appropriate ones of the status indicators aligned to provide a visual indication to the camera user of the amount of film exposed in the cassette. A spool lock mechanism is provided for locking the film spool and the exposure indicators in place thereby preventing accidental rotation of the spool and consequent misindication of the exposure status when the cassette is outside the camera.