| 摘要 |
PURPOSE:To provide focusing without any overshooting even in a range finding state wherein an integration time is long and to reduce hunting wind in a focusing state by varying a speed control range according to the integration time. CONSTITUTION:A sensor 4 independently outputs an electric signal corresponding to the quantity of incident light, the output is independently amplified by an amplifier 5, an adder subtracter 6 calculates the sum signal (A+B) of and difference signal (A-B) between two division sensor outputs A and B; and an integrator 8 integrates the synchronism detection signal of a synchronism detector 7, and a comparator 9 converts the integration level of the difference signal into a digital level, which is inputted to a microcomputer 10. The microcomputer 10 calculates a defocusing quantity from the integration level of the obtained difference signal and controls a driver 11 to control an AF motor 12. In this case, the speed control range when the integration time is long is varied to widen the range wherein the speed is slow, thereby reducing the hunting width in the focusing state. |
