| 摘要 |
PURPOSE:To prevent the decrease in distance measurement accuracy by various full aperture value lenses and make possible the detection of automatic focusing even at the large full aperture value by selecting plural kinds of a pair of photo sensor groups according to the lens full aperture values. CONSTITUTION:The incident light quantity photo detecting signals through the photographing lens by pairs of photo sensor groups SA10... and SB10, SA20... and SB20..., SA30 and SB30... of different distances of the array elements 13 which are scanned and driven by a photo sensor drive circuit 14 go through a multiplexer 8 and become the distance measurement signals of coincidence type. This multiplexer 8 is controlled by the lens full aperture signal and the sensor groups SA10... and SB10..., SA20... and SB10...,... are selected according to the lens full aperture, thus the occurrence of photo detection errors is obviated by the correct photo sensor groups of different distances, and the base distance at the distance measurement becomes a correct value, due to which the distance measurement accuracy does not decrease irrespective of the full aperture. Hence, the automatic focus detection is accomplished even if the full aperture range is expanded. |
