A camera having a sprocket with a pair of cogs formed on a periphery for engaging a filmstrip having a row of perforations separated at alternate short and long intervals. The periphery is divided by the cogs into a frictional engaging section which provides frictional engagement of the periphery with the filmstrip and a mechanical engaging section which provides mechanical engagement of the cogs with the perforations. A shutter charging mechanism is operated by rotation of the sprocket driven by the filmstrip through the mechanical engagement between the filmstrip and at least part of the mechanically engaging section of the sprocket. A switch over mechanism disconnects the sprocket and the shutter mechanism in response to rewinding the filmstrip and a locking mechanism prevents reverse rotation of the sprocket in a specific position.