Focus detecting apparatus for determining whether an object is moving

摘要

A focus detecting apparatus that includes an optical system having a group of focusing lenses. An object distance measuring device measures a defocus amount for a specific object imaged by the optical system. A focus judging device determines a focus state in accordance with a measurement of the object distance measuring device. A lens driver then drives the focusing lens group to a focal position, in accordance with the amount of defocus, wherein the apparatus includes a controller for repeatedly operating the object distance measuring device and the lens driver. A moving object judging device determines that the specific object is a moving object when the focus judging device determines an out-of-focus state more than one time during the repeated operations.