Patent ID: 7675568

Claim:
A diaphragm control apparatus comprising: a diaphragm unit having movable diaphragm blades, the diaphragm unit configured to control the positioning of the diaphragm blades to adjust a quantity of light passing through the diaphragm unit; a diaphragm state detection unit configured to detect a state of the diaphragm unit; a diaphragm state designation unit configured to designate a target position for the diaphragm blades to be positioned thereto; and a control unit configured to perform a driving control operation by the diaphragm unit based on a difference between an output of the diaphragm state detection unit and the target position, wherein the control unit is configured to set a neutral zone for prohibiting the driving control operation when the difference is less than a defined amount, and the neutral zone is determined based on a detected state of the diaphragm unit.