Patent ID: 8044331

Claim:
A image pickup apparatus, comprising: an optical system; an optical wavefront modulation element operable to modulate an optical transfer function; an aperture stop located adjacent to the optical wavefront modulation element such that the following condition is satisfied: φ× D< 2 mm 2 , where φ [mm] is an aperture diameter of the aperture stop, and D [mm] is a distance between the aperture stop and the optical wavefront modulation element; and an image pickup device operable to pick up an object image that passes through the optical system and the optical wavefront modulation element, wherein, a phase of the optical wavefront modulation element is based on the following relationship: z = exp ⁢ { ⅈ × ( ∑ j = 1 ⁢ C j ⁢ x m ⁢ y n ) } , where z is the phase of the optical wavefront modulation element on an optical axis of the optical system and x and y are axes perpendicular to the optical axis and to each other, i is √{square root over (−1)}, C is a coefficient value, m and n are integers, j = [ ( m + n ) 2 + m + 3 ⁢ n ] 2 ,  x  ≤ 1 , and ⁢ ⁢  y  ≤ 1.