Shutter apparatus, image pickup apparatus, and control method for the shutter apparatus

An image pickup apparatus comprising:

• a motor configured to drive in a full step driving mode that electrifies each phase with a constant electrification amount, and a micro step driving mode that stepwise changes an electrification amount and electrifies each phase;
• a cam gear connected to an output shaft of the motor and including a cam part;
• a driving member including a cam follower configured to slide in the cam part;
• and
• a blade group configured to move between an open state that opens an opening used for an exposure and a closed state that closes the opening, via the cam gear and the driving member as the motor rotates,
• wherein the cam part includes a blade maintaining section configured to maintain one of the open state and the closed state of the blade group when the cam follower slides, and a blade driving section configured to move the blade group from the one of the open state and the closed state to the other of the open state and the closed state when the cam follower slides, and
• wherein where the cam follower slides in the blade maintaining section and the blade driving section in this order, the motor is driven in the micro step driving mode when the cam follower slides in the blade maintaining section, and the motor is driven in the full step driving mode when the cam follower slides in the blade driving section.