Foreign substances adhered to a focal plane shutter are shaken off by vibrationally driving the shutter a plurality of times in succession while the focal plane shutter, which controls the incidence of light on a photoelectric transducer converting an optical image of a photographic object into an electrical signal, shields the photoelectric transducer from light incident thereon. In other words, implementing vibrational removal of adhered foreign substances by means of overloading the focal plane shutter.