An apparatus includes: a synchronizing signal generation portion outputting a synchronizing signal periodically; a diaphragm; an imaging portion operated based on the synchronizing signal to pick up a subject image through the diaphragm and generate image data; a trigger input portion operable to input a trigger signal commanding a start of a photographing operation by the imaging portion; and a control portion controlling the operation of the imaging portion. The control portion controls synchronous processing for operating the diaphragm in synchronization with the synchronizing signal. When the trigger signal is input, the control portion stops the generation of the synchronizing signal by the synchronizing signal generation portion and thereafter resumes the generation of the synchronizing signal, while when the synchronous processing is being performed, the control portion initializes the synchronous processing before resuming the generation of the synchronizing signal.