Patent ID: 8681431

Claim:
A zoom lens comprising: a first lens unit configured to be disposed closest to an object of all lens units within the zoom lens and having a positive optical power; and at least one subsequent lens unit configured to be disposed closer to an image than the first lens unit, wherein the first lens unit is configured to move toward the object during variation of magnification from a wide-angle end to a telephoto end, and wherein the first lens unit comprises at least three lenses including a positive meniscus lens configured to be disposed closest to the image among the at least three lenses and having an image side concave surface, and a negative lens configured to be disposed on an object side next to the positive meniscus lens, and satisfies the following condition: 1.55 <Rpi/f 1<2.90, where Rpi represents a curvature radius of the image side concave surface of the positive meniscus lens, and f 1 represents a focal length of the first lens unit, wherein the negative lens in the first lens unit is a negative meniscus lens having an object side convex surface, and satisfies the following condition: 0.50 <Rpi/Rno< 6.00, where Rno represents a curvature radius of the object side convex surface of the negative meniscus lens, and wherein the zoom lens satisfies the following condition: 1.50 <Nn< 1.68, where Nn represents a refractive index of a material forming the negative lens.