Patent ID: 7911525
Filing Date: 2011-03-22
Classification: H04N

Abstract:
1. A focusing apparatus comprising: a first detecting unit configured to output an electric signal from an optical image formed through an image pickup optical system including a focus lens and a zoom lens and detect a focus signal showing a sharpness of the optical image from the output electric signal; a second detecting unit configured to detect an in-focus position with an optical system provided separately from the image pickup optical system; a memory recording information indicating relation of a focus lens position and the zoom lens position corresponding to object distance of an object; and a control unit configured to drive and control the focus lens, wherein, while driving and controlling the focus lens to bring the object into focus in accordance with a change of a focal length and the object distance, the control unit drives and controls the focus lens using the output from the first detecting unit and an output from the second detecting unit when the positions of the focus lens and the zoom lens are in a first relation, and the control unit drives and controls the focus lens using the output from the first detecting unit without using the output from the second detecting unit when the positions of the focus lens and the zoom lens are in a second relation that a focus of the image pickup optical system is on a closer distance side with respect to a predetermined position compared to the first relation, and wherein the control unit determines the in-focus position of the focus lens based on the outputs from the first detecting unit and the second detecting unit when a present position of the focus lens is on an infinity side with respect to the predetermined position.