| 摘要 |
PURPOSE:To obtain a single-lens reflex camera provided with a compact focusing detecting system of high focusing accuracy by using space around a penta roof prism. CONSTITUTION:After forming an image near the focusing screen 3 of the first image-forming plane of a photographing lens, luminous flux from an object passes through a penta roof prism 4, and taken out from a luminous flux take- out port 4R' of the penta roof prism 4, and splited into two luminous fluxes by a light splitting prism 5, and led on photodetecting elements 9a, 9b by a secondary image-forming lenses 6a, 6b through reflection prisms 7a, 7b and total reflection mirrors 8a, 8b. As the secondary image-forming lenses are provided in a space of subject side of the penta roof prism, the distance between the first image-forming plane and the secondary image-forming lenses can be set properly. Accordingly, specified image-forming magnification can be obtained and accuracy of focusing can be heightened by this optical arrangement. |
