Patent ID: 9568716
Date: 2017-02-14
CPC Classifications: G02B

Claim:
1. A zoom lens consisting of: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having negative refractive power; and a fifth lens group having positive refractive power in this order from an object side, wherein distances between the lens groups change during magnification change, and the first lens group is positioned closer to the object side in a telephoto end state than its position in a wide angle end state, and wherein the first lens group consists of three lenses of an 11th lens having negative refractive power, a 12th lens having positive refractive power and a 13th lens having positive refractive power in this order from the object side, and wherein the following conditional expressions are satisfied: Nd11: a refractive index of the 11-th lens for d-line, νd11: an Abbe number of the 11-th lens for d-line, νd12: an Abbe number of the 12-th lens for d-line, f2: a focal length of the second lens group, ft: a focal length of an entire system at a telephoto end, and f1: a focal length of the first lens group.