A photo
diode and a
resistor are connected to each other in series. A gate of a FET is connected to the connection of the photo
diode and the
resistor. When a photometry switch is turned on, the photo
diode generates a photo current according to a subject brightness. A
potential difference is generated between the both terminal of the
resistor. When the subject brightness is less than a threshold level, the FET is not turned on because of low
potential difference of the resistor. When a subject brightness is equal to or more than the threshold level, the FET is turned on because of
high potential difference of the resistor. A first
transistor turned to be in a state opposite to the FET and a second
transistor turned on and off according the state of the first
transistor are provided. When the FET is turned off, the second transistor is turned on, and a solenoid is powered. The solenoid moves a stop plate out of an
optical axis such that an
exposure is taken through a large stop opening. When the FET is turned on, the second transistor is turned off, so the solenoid is not driven. Since the stop plate is set on the
optical axis, an
exposure is taken through a stop-down opening.