Patent ID: 7940474

Claim:
A zoom lens comprising: a first lens group having a negative refractive power; a second lens group having a positive refractive power; and a third lens group having a positive refractive power, wherein the first, second, and third lens groups are arranged sequentially from an object side to an image side, and the lens groups are moved during zooming from a wide-angle position to a telephoto position so that the distance between the first lens group and the second lens group is reduced and the distance between the second lens group and the third lens group is changed, and the zoom lens satisfies the following inequalities −1.3 <f 1 /f 2 <−1.0 1.6 <f 2 /f w <2.0 4.5 <f 3 /f w <5.2, where, f 1 , f 2 , f 3 and f w respectively denote the focal length of the first lens group, the focal length of the second lens group, the focal length of the third lens group, and the overall focal length of the zoom lens at the wide-angle position; wherein the second lens group includes four lenses that are arranged sequentially from the object side to have positive refractive power, positive refractive power, negative refractive power, and positive refractive power, respectively.