Patent ID: 9709781
Date: 2017-07-18
CPC Classifications: G02B,H04N

Claim:
1. A zoom lens having a wide angle end and a telephoto end, comprising: a first lens unit having a positive refractive power that does not move for zooming; a second lens unit having a negative refractive power that moves during zooming and comprising at least one positive lens and at least one negative lens; at least one other lens unit that moves during zooming as at least a third lens unit; a rearmost lens unit disposed closest to an image side that does not move for zooming and comprising at least one negative lens, wherein the first lens unit, the second lens unit, the at least one other lens unit, and the rearmost lens unit are arranged in the stated order from an object side to the image side; and an aperture stop arranged in the image side of the second lens unit, wherein the following conditions are satisfied: where νd2p and νd2n respectively represent average values of Abbe numbers of positive lenses and negative lenses forming the second lens unit, θgf2p and θgf2n respectively represent average values of relative partial dispersions of the positive lenses and the negative lenses forming the second lens unit, Δθgfrn1 represents anomalous dispersion of a lens having a smallest Abbe number among negative lenses forming the rearmost lens unit, TD represents a distance on an optical axis from a surface vertex position of a lens surface closest to the object side of the zoom lens to a surface vertex position of a lens surface closest to the image side of the zoom lens, and Drn1 represents a distance between the aperture stop and the lens having the smallest Abbe number among the negative lenses forming the rearmost lens unit, at the wide angle end of the zoom lens, provided that: an Abbe number νd is expressed as: where NF represents a refractive index with respect to an F-line, Nd represents a refractive index with respect to a d-line, and NC represents a refractive index with respect to a C-line, a relative partial dispersion θgf is expressed as: where Ng represents a refractive index with respect to a g-line, and anomalous dispersion Δθgf is expressed using the relative partial dispersion θgf and the Abbe number νd as: