Patent ID: 7324288

Claim:
A zoom lens system comprising, in order from an object side to an image side: a first lens unit having a negative optical power: a second lens unit having a positive optical power; and a third lens unit having a positive optical power, wherein an interval between the first and second lens units, and an interval between the second and third lens units change during zooming, and assuming that a movement amount of the second lens unit during the zooming from a wide-angle end to a telephoto end is Δ 2 x, the interval between the second and third lens units in the wide-angle end is D 23 W, focal lengths of the first and second lens units are f 1 and f 2 , respectively, and the focal length of the whole system in the wide-angle end is fW, the following conditions are satisfied: 1.7<Δ 2 X/√{square root over (|f 1 *f 2 |)}<2.3; and 0.5<D 23 W/fW<1.2.