Patent ID: 8638506

Claim:
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 sp-A ) satisfying following condition, where the distance (d sp-A ) is a distance in the optical axis direction from the aperture portion (SP) to the object-side surface vertex of the optical element (A) and a length on an optical axis from an object-side surface vertex of a lens closest to the object side to an image plane is L, 0.00 <d sp-A /L< 0.12 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: 4.0 <f 2 /( f 1 ×Fno×d 1 )<10.0 −0.10<Δθ gFA ×φ A /(ν dA ×φ)<−0.01.