Abstract: An auto-focus device, for eliminating an uncomfortable feeling when phase difference AF is switched to optical path length difference AF when an arbitrary area is set as a focusing target area, and a method for controlling operation of the same. A desired area is set as the focusing target area. Until a first threshold value position is reached, the focus lens is moved based on a phase difference AF evaluation value obtained from a phase difference AF sensor so as to bring the center portion of the imaging area into focus. Until a second threshold value position is reached, the focus lens is moved based on a phase difference AF evaluation value which is obtained from a signal of an area corresponding to the set focusing target area. When the focus lens reaches the second threshold value position, the focus lens is positioned at the focusing position.

Abstract: This invention provides an auto-focus device, which is for eliminating an uncomfortable feeling when phase difference AF is switched to optical path length difference AF when an arbitrary area is set as a focusing target area, and a method for controlling operation of the same. A cameraman sets a desired area as the focusing target area. Until a focus lens reaches a first threshold value position, the focus lens is moved on the basis of a phase difference AF evaluation value obtained from a phase difference AF sensor so as to bring the center portion of the imaging area into focus. Until the focus lens reaches a second threshold value position, the focus lens is moved on the basis of a phase difference AF evaluation value which is output from a phase difference imaging element and is obtained from a signal of an area corresponding to the set focusing target area.