Abstract: A camera, in particular a system camera, with a camera housing and an interchangeable lens, which can be interchangeably fitted by a connection device, in particular a bayonet attachment, in a connect device of the camera housing, in particular a bayonet receptacle, in which, for supplying power to electrical actuating devices in the interchangeable lens, the connecting device of the camera housing has only two power supply contacts, to which two connection contacts are assigned in the connection device of the interchangeable lens, while exclusively one opto-coupling is provided in the interface for the purpose of transmitting control signals from the interchangeable lens to the camera housing and/or vice versa, the opto-coupling in each case having an optical signal generator and a signal pickup assigned thereto.