Automatic focusing device of camera having highly reliable movement

Abstract

An automatic focusing device of camera is adapted to control the lens to focus on an object moving along the optical axis of the lens. The focus detecting section of the device outputs a plurality of focus detection signals according to the focused state of the image of the object formed by the camera lens. The correlation computing section of the device computationally determines the correlation between the last focus detection signal and the preceding focus detection signals in order to predict the movement of the object according to the plurality of focus detection signals output from the focus detecting section. A reliability judging section of the device judges the reliability of the outcome of the computationally determining operation of the correlation computing section. The movement judging section judges on the object for mobility or immobility according to the outcome of the computationally determining operation of the correlation computing section and that of the reliability judging operation of the reliability judging section. The movement judging section determines the object to be moving when it judges the outcome of the reliability judging operation of the reliability judging section as poorly reliable.