Motion picture sound camera

A motion picture sound camera wherein a chamber in the camera housing can receive relatively small containers for regular motion picture film or relatively large containers for sound film. When the chamber receives a large container, the latter deforms a leaf spring which is thereby disengaged from a lever serving to move a component of the sound recording mechanism into engagement with an accessible portion of sound film in the inserted container. The lever can be moved in the opposite direction by a knob which is accessible from without the housing and is turnable by hand between a first and a second position. When moved from the first to the second position, the knob moves the lever and the component to a retracted position while simultaneously stressing a resilient ejector for containers in the chamber, unlocking the door for the chamber and resetting a film frame counter to starting position. When the knob is moved from the second to the first position, the lever moves the component into engagement with film if the chamber contains a container for sound film; at the same time, the knob deactivates the ejector, locks the door in closed position, and moves the frame counter into engagement with a rotary output member of the film transporting mechanism in the camera housing.