Patent ID: 8284276

Claim:
A zoom lens system, in order from an object side to an image side, comprising a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein the first lens unit is composed of three or fewer lens elements, wherein the second lens unit is composed of three lens elements, wherein in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein the following conditions (5), (6), (a-2) and (b) are satisfied: tan 2ω W ×m 2W ≦−1.78 (5) tan 2ω W ×|f G2 |/f G1 ≧1.25 (6) ω W ≧37 (a-2) f T /f W ≧10 (b) where, m 2W is a lateral magnification of the second lens unit at a wide-angle limit in an infinity in-focus condition, f G1 is a composite focal length of the first lens unit, f G2 is a composite focal length of the second lens unit, ω W is a half view angle (°) at a wide-angle limit, f T is a focal length of the entire system at a telephoto limit, and f W is a focal length of the entire system at a wide-angle limit.