Patent ID: 8154806

Claim:
A zoom lens system, comprising, in order from an object side to an image side: a first lens unit having a positive optical power; a second lens unit having a negative optical power; and a rear unit including at least one lens unit, wherein at least two of the first lens unit, the second lens unit, and the at least one lens unit of the rear unit move for zooming so that a distance between adjacent lens units is changed; the first lens unit includes a composite optical element in which a first optical element having a positive optical power and a second optical element having a negative optical power are cemented to each other; and the following conditions are satisfied: 2.45 <n d1p −(9.3×10 −5 ×ν d1p 2 −1.7×10 −2 ×ν d1p )<3.00; 5.0<ν d1p <80.0; 1.35<n d1n <2.35; and 5.0<ν d1n <45.0, where n d1p and v d1p denote a refractive index and an Abbe number of a material of the first optical element, respectively, and n d1n and v d1n denote a refractive index and an Abbe number of a material of the second optical element, respectively, wherein the following condition is satisfied 5.0 < ⅆ 1 ⁢ p ⅆ 1 ⁢ n < 60.0 where d 1p denotes a center thickness of the first optical element, and d 1n denotes a center thickness of the second optical element.