Patent ID: 8724232

Claim:
A zoom lens comprising, in an order from an object side to an image side: a first lens group having a negative refractive power; a second lens group having a positive refractive power; and an aperture disposed between the first lens group and the second lens group, wherein zooming is performed by varying a distance between the first lens group and the second lens group, wherein the second lens group comprises at least four lenses, wherein at least one lens surface of a lens that is disposed closest to the object side among the lenses of the second lens group is an aspherical surface, wherein at least one lens surface of a lens that is disposed closest to the image side among the lenses of the second lens group is an aspherical surface, wherein an object-side surface of a lens that is disposed third closest to the object side among the lenses of the second lens group is a convex surface, wherein a lens that is disposed second closest to the object side among the lenses of the second lens group satisfies the following expressions: 65 <vd 22 R 22a /R 22b <0, where vd 22 is an Abbe's number of the lens that is disposed second closest to the object side among the lenses of the second lens group, R 22a is a curvature radius of a lens surface on the object side of the lens that is disposed second closest to the object side among the lenses, and R 22b is a curvature radius of a lens surface on the image side of the lens that is disposed second closest to the object side among the lenses, and wherein a lens that is disposed closest to the image side among lenses of the first lens group has a positive refractive power, and the zoom lens satisfies the following expression: 25>Vd 13 where vd 13 is an Abbe's number of the lens that is disposed closest to the image side among the lenses of the first lens group.