Patent attributes
An image pickup apparatus includes an element-including optical system, a detector, and a converter. The element-including optical system has an optical system and an optical wavefront modulation element which modulates an optical transfer function. The detector picks up an object image that passes through the optical system and the optical wavefront modulation element. The converter generates an image signal with a smaller blur than that of a signal of a blurred image output from the detector by performing a filtering process of the optical transfer function to improve a contrast. A focal position of the element-including optical system is set by moving the element-including optical system to the focal position which is corresponding to a predetermined object distance using a contrast of the object based on the image signal.