Patent ID: 8736973

Claim:
A zoom lens comprising, in order from an object side to an image side, a first lens unit of a negative refractive power, a second lens unit of a positive refractive power, and a third lens unit of a positive refractive power, each lens unit being moved during zooming, wherein the second lens unit includes two positive lenses, a negative lens, and a positive lens in order from the object side to the image side, and wherein the following conditions are satisfied: 1.73 <Nd 2 p <1.92, 1.90 <Nd 2 n <2.40, and 1.90 <Dd 2/ Dd 21<4.00, where Nd 2 p denotes an average refractive index for d-line of materials of the positive lenses in the second lens unit, Nd 2 n denotes a refractive index for d-line of a material of the negative lens in the second lens unit, Dd 2 denotes a thickness of the second lens unit on an optical axis, and Dd 21 denotes a thickness of a positive lens closest to the object side of the second lens unit on the optical axis.