Abstract: When the user presses the trigger button, a rod is pulled longitudinally by a drive spring in a first direction from a first to a second position triggering the shutter in the process and a coupling thereafter couples the rod to a transport motor which returns the rod in the opposite second direction back to first position, the rod resetting the shutter in the process, the rod when returned to second position becoming decoupled from the motor so that the latter will not oppose the force of the drive spring for the next first-direction movement of the rod. The crank rod is blocked against first-direction movement by two blocking levers, the first initially being in blocking position and the second initially in unblocking position.