Patent ID: 8638506
Filing Date: 2014-01-28
Classification: G02B

Abstract:
1. A photographic optical system comprising, in order from an object side to an image side: a first lens unit having positive refractive power; a second lens unit having negative refractive power configured to move in an optical axis direction to perform focusing; a third lens unit having positive or negative refractive power; an aperture portion (SP) disposed on the image side as compared with the first lens unit to determine an axial maximum light flux diameter; and an optical element (A) in which at least an object-side surface vertex thereof is located within the range of a distance (d wherein, when a focal length of the entire photographic optical system is f, an optical power of the entire photographic optical system is φ, a focal length of the first lens unit is f 1 , a full-aperture F-number when an infinitely distant object is focused is Fno, a length on the optical axis from an object-side surface vertex of a lens closest to the object side in the first lens unit to an image-side surface vertex of a lens closest to the image side in the first lens unit is d 1 , an optical power of the optical element (A) is φ A , a d-line-based Abbe number of a material constituting the optical element (A) is ν dA , and a partial dispersion ratio difference of the material constituting the optical element (A) is Δθ gFA , following conditions are satisfied: