| 摘要 |
PURPOSE:To enable the easy decision of the focused position by detecting the moving direction of an objective lens by the use of two contrast-detecting sensors thereby performing focus detection. CONSTITUTION:The respective contrast signals of the sensor 4 installed on a film equivalent plane and the sensor 5 installed on the plane parallel to the film equivalent plane and differing in optical distance from the objective lens are detected by circuits 18, 18'. A pulse waveform appears when the peak pass pulse appears from an AND circuit AND4 when the lens is moving in either of the extension directions. The signal of the circuit 18 is detected of its peak value by the peak holding circuit constituted by an operational amplifier OP5, capacitor C1, etc. This value is comared with the signal of the circuit 18 by a comparator 4. These inputs are controlled of pass time by the output of an FFF1 into which the output of the AND4 is inputted. The comparator 4 outputs the focus coincidence signal when the two inputs are equal so that it lights an LED. |
