| 摘要 |
PROBLEM TO BE SOLVED: To prevent a range-finding feasible range by auxiliary light from being reduced even in the case the power source voltage falls down. SOLUTION: In the case the AF auxiliary light is required, a control circuit 13 measures the voltage V of a battery E by using a voltage detection circuit 14 so as to confirm the battery voltage. When the battery voltage V is equal to or under specified voltage Va, the maximum value of the operation time of an AF sensor 10 is changed to a larger value than an initialized value. Then, a distance from a subject is arithmetically calculated according to information on a subject image obtained by emitting the AF auxiliary light from a light emitting element 71 and receiving the reflected light of the auxiliary light reflected from a subject by using the AF sensor 10 during the time of the maximum value of the operation time after the change. In the case the power source voltage becomes low and the quantity of the AF auxiliary light becomes small, the operation time of the AF sensor 10 is made longer so that the range from the subject by the AF auxiliary light may not be reduced. |
