AUTOMATIC FOCUS ADJUSTMENT DEVICE AND METHOD

An automatic focus adjustment device that can effect focussing on a moving subject. The automatic focus adjustment device includes a lens driving device, a focus state detection device that detects the defocus amount, an image velocity computation device that computes the subject image movement velocity, and a moving subject prediction device that computes a predicted value for the defocus amount at exposure based on the defocus amounts and the subject image movement velocity. The device also includes a predicted position control device that scrolls the shooting lens by the predicted value, a position velocity control device that controls the scrolling amount in accordance with the defocus amount and the amount of change of the defocus amount with time, a determination device that determines whether or not the control action of the predicted position control device can be completed before exposure, and prior to a release a selection device selects control by the predicted position control device. After release, the selection device selects control by the predicted position control device when the determination device determines the control action can be completed. Otherwise, the selection device selects control by the position velocity control device.