| 摘要 |
PURPOSE:To make it possible to perform automatic focusing operation with rapidity and stability by detecting the image surface moving speed of an image forming optical system on an image surface position accompanying the movement of an object and predicting a future image surface position by using an amount which is obtained by multiplying an image surface moving speed by a prescribed constant. CONSTITUTION:The timing of starting and ending charge storage is transmitted to a control means 109 by a focus detecting means 104 for detecting the focusing state of a photographic lens 101. A period from the end of the charge storage to the start of the succeeding charge storage is applied to the charge transfer and the calculation of a defocusing amount. The image surface moving speed of the image forming optical system on the image forming position accompanying the movement of the object is calculated based on plural defocusing amounts calculated by the focus detecting means 104, the amount due to the movement of the image forming optical system and an interval of the storage time which is the cause for the calculation of plural defocusing amounts. A future image surface position is predicted by using the amount which is obtained by multiplying the image surface moving speed by the prescribed constant, and then, the image forming optical system is driven toward the predicted future image surface position. |
