Patent ID: 7085069

Claim:
A zoom lens having an object side and an image side and comprising four lens groups, arranged in order from the object side of the zoom lens along an optical axis, as follows: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group; and a fourth lens group having positive refractive power; wherein the first lens group and the fourth lens group do not move during zooming; the second lens group and the third lens group are moved along the optical axis during zooming; the first lens group includes, arranged in order from the object side of the zoom lens along the optical axis, a first lens subgroup having negative refractive power that does not move during focusing of the zoom lens, a second lens subgroup having positive refractive power that moves during focusing of the zoom lens, and a third lens subgroup having positive refractive power that does not move during focusing of the zoom lens; and the second lens subgroup includes, arranged in order from the object side of the zoom lens along the optical axis, a first lens element having negative refractive power, a second lens element having positive refractive power, and a third lens element having positive refractive power.