When photographing using an optical finer, a hold member rotates, and a pressing member pushes a pushed portion of an iron piece member to rotate an unlocking member for a first blade and an unlocking member for a second blade to bring the iron piece member into contact with an iron core member of an electromagnet. When photographing using an electronic finder, a permanent magnet rotor of an electromagnetic device is rotated in a state where the electromagnet is not magnetized, a deterring member is made to face the operation locus of a deterred portion of the unlocking member for a second blade, and then, the hold member is rotated. Thereby, the unlocking member for a second blade is deterred by the deterring member so as to allow observation using the electronic finder without pushing the locking member for a second blade.