Patent ID: 8284499

Claim:
A zoom lens comprising, a combination of only three lens groups including: in order from an object side to an image side: a first lens group which has a negative refractive power; a second lens group which has a positive refractive power; and a third lens group which has a positive refractive power, wherein the second lens group is disposed directly between the first and third lens groups, wherein the first lens group includes a single compound aspheric lens formed of a spherical glass lens which has a negative refractive power and a resin lens which has a positive refractive power and whose image side surface is formed to be aspheric, wherein the following conditional expressions (1) to (4) are satisfied f 11 /fw<− 1.8, (1) 1.55 <n 11, (2) 55<ν11, and (3) G 1 r 1<−16.5, (4) where f11 is a focal length of the spherical glass lens in the first lens group, fw is a focal length of the whole lens system at a wide-angle end, n11 is a refractive index of the spherical glass lens in the first lens group at the d-line, ν11 is an Abbe number of the spherical glass lens in the first lens group at the d-line, and G1r1 is a radius of curvature of an object side surface of the spherical glass lens in the first lens group.