| 摘要 |
PURPOSE:To surely compute a defocused amount and its direction and to guide a photographing lens up to a focusing position by deciding whether a current state is a normal state for finding out the defocused amount and its direction or not, and when abnormality is decided, decelerating the driving speed of the lens. CONSTITUTION:An image face moving speed detecting circuit 21 calculates an image face moving speed on a film surface based on the movement of the photographing lens 4 from the number of pulses corresponding to driving data obtained from driving data generating circuits 10a, 10b and the rotational amount of a motor 7 obtained from an encoder 8. A deciding circuit 22 decides whether the current state is a normal state for finding out a defocused amount and a defocusing direction based on the calculated image face moving variable and the charge accumulating time of an image sensor 5 obtained from an accumulation time control circuit 15 and controls a drive control circuit 11 based on a decided result. These circuits 21, 22 are controlled by a central control circuit 30. |
