| 摘要 |
PURPOSE:To offer a focus detecting device capable of detecting a focus stably by switching a decided value according to a focal length, a lens position, magnification, etc., when a correlation obtained by comparing two picture signals is compared with the decided value to determine whether a focus can be detected or not. CONSTITUTION:The 1st and 2nd picture signals made incident on a light receiving means 14 through two parts over the optical axis of a photographing lens 2 from a object are compared with each other to calculate a correlation of a combination of things with the highest agreement. The relative interval between to images is detected from the correlation, and defocus quantity from the focusing position of the photographing lens 2 is calculated to detect a focus. To judge whether focus detection is possible or not, the correlation from picture data is compared with a set decided value. When the decided value is switched to a severe value, for instance, the feasibility of focus detection can be decided surely without mistakenly detecting the focusing position in an unfocused state, and the focus can be detected stably. |
