Camera having a zoom lens unit

摘要

An automatic focusing apparatus according to the present invention comprises a photo-taking lens system, in which a focus has to be adjusted every time the focal length is changed, including at least a first lens unit for changing the focal length by means of its movement along an optical axis of the photo-taking lens during the zooming operation and a second lens unit for adjusting the focus by means of its movement along the optical axis, and a controller for controlling the speed of the second lens unit during the zooming operation based on the focal length of the photo-taking lens system, the lapse of the time related with focus detection cycles, the reliability of the result of the focus detection and so on.