| 摘要 |
PURPOSE:To surely predict a distance from a subject after a predetermined time has passed without affected by a focal distance of a lens and to surely focus on the moving subject by predicting movement of the subject based on change in a defocusing amount and a photographing lens position. CONSTITUTION:A defocusing amount of a photographing optical system is detected, the defocusing amount after a predetermined time has passed is predicted by change in the detected defocusing amount and a driving amount of the photographing lens is obtained by the detected defocusing amount. And a calculating means calculates the defocusing amounts at a first point of time and a second point of time after a first predetermined time has passed, respectively (B1, B2), and a detecting means detects a total delivery amount of the photographing lens from an infinite far position (B3). A predicting and calculating means predicts the defocusing amount at a third point of time after a second predetermined time has passed in continuation from the first predetermined time from the defocusing amounts at the first and the second points of time and the delivery amount (B6). |
