| 摘要 |
PURPOSE:To constitute the device so that enlargement of a distance measuring range and improvement of focusing accuracy are satisfied, and also, a focus can be detected irrespective of the direction of contrast, even a photographic lens whose FNo. is comparatively dark can be applied, and the device is compact and can be mounted easily. CONSTITUTION:With regard to a focus detection system in which image re- forming lenses 21a, 21b through which a luminous flux passing through an opening part transmits and photodetector trains 22, 23 in its image forming position are placed, in the rear of a diaphragm 20 having a pair of opening parts arranged at an interval which can secure focusing accuracy, a first and a second focus detection systems in which the parallel directions of the opening parts are orthogonal, and also, the magnifications are different from each other are provided. The device constituted so that a luminous flux forms an image on the first face by making a focal distance and optical path length of both the image re-forming lenses 21a, 21b different from each other. |
