Patent ID: 7457046

Claim:
A zoom lens system comprising, in order from an object side to an image side: a first lens unit with a positive optical power; a second lens unit with a negative optical power, the second lens unit consisting of, in order from the object side to the image side, a first lens element with a negative optical power, a second lens element with a negative optical power, and a third lens element with a positive optical power, the first lens element having an image side surface whose absolute value of the optical power is greater than that of an object side surface thereof, the second lens element having an object side surface with a concave shape, the third lens element being disposed across an interval from the second lens element and having an object side surface with a convex shape; and at least one lens unit; wherein at least one of the first lens unit and the second lens unit is moved during zooming, and the following conditions are satisfied: υ<20.0 1.65< (N21+N22)/2 where υ represents an Abbe's number of a material forming the third lens element, and N21 and N22 represent refractive indices of materials forming the first lens element and the second lens element, respectively.