Patent ID: 6989943

Claim:
A zoom lens system, comprising: a first lens unit having negative optical power, the first lens unit including a first lens element having negative optical power, a second lens element having negative optical power, and a third lens element having positive optical power, which are disposed in order from an object side to an image side, the first lens element having an aspherical surface of a shape that the negative optical power decreases from a lens central portion to a lens peripheral portion, the second lens element being formed in a meniscus shape which is convex on the object side; a second lens unit having positive optical power; and a third lens unit having positive optical power, wherein the first lens unit, the second lens unit, and the third lens unit are disposed in order from the object side to the image side, wherein the second lens unit is moved toward the object side in zooming from a wide angle end to a telephoto end such that an interval between the first lens unit and the second lens unit at the telephoto end becomes smaller than an interval between the first lens unit and the second lens unit at the wide angle end, and wherein the following conditions are satisfied, 1.78<Ng 1 and 1.75<Ng 2 where Ng 1 is a refractive index of a material constituting the first lens element and Ng 2 is a refractive index of a material constituting the second lens element.