| 摘要 |
PURPOSE:To perform automatic speedy focusing operation with high percision by detecting the deviation of an actual subject image formation surface from a prescribed image formation surface and then generating an image plane movement extent signal and a focal length signal, and controlling the extent of driving of a focusing lens. CONSTITUTION:Generating means 27, 28, and 29 for image plane movement extent signals convert the driving extent of a focusing lens L1 into an image plane movement extent signal showing the extent of movement of an image plane accompanying the driving in prescribed relation irrelevant to variation in focal length, and generating means 36 and 37 for focal length signals generate the focal length signal relating to the set focal length of an influencing lens with variable focal length to control the driving extent of the focusing lens L1 on the basis of the image plane movement extent signal and the image plane shift signal of a focuse detector 6. Consequently, even when the focal length is varied, the focusing lens L1 is driven to move the image plane by the image plane shift detected by the focus detector 6 all the time. Thus, automatic speedy focusing operation with high precision is carried out. |
