| 摘要 |
PURPOSE:To reduce the influence of tandelta of a capacitor for detecting subject brightness or distance to a subject as much as possible and to obtain accurate detection data by providing the capacitor for range finding with a clipping circuit. CONSTITUTION:A range finding processing part B measures the time (when the output of a comparator 3 is at a high level) up to the coincidence of the voltage Vc of a capacitor Cs charge with a constant current with a range finding voltage Va proportional to the distance to the subject by a CPU 1, and range finding processing is carried out. The series circuit of two diodes D1 and D2 is connected across the capacitor C2 and the maximum charging voltage of this capacitor C2 is clipped. Consequently, the voltage of the capacitor C2 never becomes transient and a charge remaining after initialization is suppressed to an extent where there is no trouble to practical use. |
