| 摘要 |
PURPOSE:To extend an auxiliary right reachable distance by determining large an auxiliary light passing area for detecting a focus, based on the brightest photographic lens of photographic lenses as a reference. CONSTITUTION:An auxiliary light passing area 1c is positioned so as to step over an enveloping circle 28 (dotted line) for surrounding luminous flux passing areas 1a, 1b for focus detection which have been set, based on the darkest photographic lens 27 as a reference, and also, set to an area contained in an exit pupil of the brightest photographic lens 1. The auxiliary light passing area 1c is not contained in the exit pupil in case of the darkest photographic lens 27, therefore, only auxiliary light for passing through an inside area 1c-1 is projected, and the auxiliary light of an outside area 1c-2 is cut. To say nothing of the case of the brightest photographic lens 1, even in case of the case of the darkest photographic lens 27, an area of the inside area 1c-1 which the auxiliary light passes through can be made larger than a circle contained therein. In such a way, the auxiliary light reachable distance can be extended, as well. |
