Patent ID: 7817346

Claim:
A zoom lens, comprising, in an order from an object side: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; and a fourth lens group having positive refractive power, and wherein: during power variation from a wide-angle end to a telephoto end, a distance between the first lens group and the second lens group increases, a distance between the second lens group and the third lens group decreases, and a distance between the third lens group and the fourth lens group decreases, and the zoom lens includes in the fourth lens group at least one cemented-triplet lens block having negative refractive power, wherein the following conditional formula (2) is satisfied: 0.8 <f 2 /fw<− 0.2, (2) where: f2 represents a composite focal length of the second lens group, and fw represents a composite focal length of a total system at the wide-angle end.