Patent ID: 6888684

Claim:
A zoom lens formed of only four lens groups, in order from the object side along an optical axis: 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 fourth lens group includes, in order from the object side along the optical axis, a front lens subgroup and a rear lens subgroup with the distance along the optical axis between the front lens subgroup and the rear lens subgroup being greater than the distance between any adjacent lens elements of the front lens subgroup or any adjacent lens elements of the rear lens subgroup; the rear lens subgroup includes, in order from the object side along the optical axis, a first lens component having positive refractive power, a lens element, another lens element, one of said lens elements having positive refractive power, a further lens element and an additional lens element that is intimately bonded to said further lens element, and another lens component having positive refractive power; and the following conditions are satisfied: N 1 >1.7 Î½<30 where N 1 is the refractive index at the e-line of a lens element having positive refractive power of the first two lens elements on the image side of said first lens component; and Î½ is the Abbe number at the d-line of a lens element having positive refractive power of the first two lens elements on the image side of said first lens component.