Patent ID: 8665531

Claim:
A zoom lens comprising, from an object side: a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; and a subsequent lens unit, wherein the first lens unit includes an optical element composed of an anomalous dispersion optical material, a positive lens, and a negative lens, and wherein the following conditional expressions are satisfied 100 < vdp * fp Δθ g , Fp * fw × ft < 1200 ( 1 ) - 10.0 < ( R ⁢ ⁢ 2 ⁢ ⁢ n + R ⁢ ⁢ 1 ⁢ ⁢ n ) / ( R ⁢ ⁢ 2 ⁢ ⁢ n - R ⁢ ⁢ 1 ⁢ ⁢ n ) < - 3.3 ( 2 ) 2.8 < vdp ⁢ ⁢ 1 / vdn < 6.0 , ( 3 ) where fw is a focal length of the entire zoom lens at a wide angle end, ft is a focal length of the entire zoom lens at a telephoto end, fp is a focal length of the optical element composed of the anomalous dispersion optical material, θ g,Fp is a partial dispersion ratio of the anomalous dispersion optical material, Δθ g,Fp is θ g,Fp −(−0.001682×vdp+0.6438), vdp is an Abbe number of the optical element composed of the anomalous dispersion optical material, vdp 1 is an Abbe number of a positive lens having the highest power in the first lens unit, vdn is an Abbe number of a negative lens having the highest power in the first lens unit, R 1 n is a radius of curvature of an object-side surface of the negative lens having the highest power in the first lens unit, and R 2 n is a radius of curvature of an image-side surface of the negative lens having the highest power in the first lens unit.