Patent ID: 9235035
Filing Date: 2016-01-12
CPC Classification: G02B

Claim Text:
1. A zoom lens substantially consisting of a first lens group having positive refractive power, which is fixed while changing magnification; a second lens group having negative refractive power, which moves from the object side to the image side while changing magnification from the wide angle end to the telephoto end; a third lens group having negative refractive power, which corrects movement of an image surface while changing magnification; and a fourth lens group, which is fixed while changing magnification, having positive refractive power and an aperture stop in this order from the object side, wherein the first lens group includes a negative meniscus lens on the most-object side; the second lens group is composed of a second-a lens group having negative refractive power and at least one aspheric surface and a second-b lens group having positive refractive power in this order from the object side, and the distance between the second-a lens group and the second-b lens group is changed while changing magnification; and the third lens group moves such that the distance between the third lens group and the fourth lens group becomes narrower at the telephoto end than at the wide angle end; and conditional expression (1) below is satisfied: N1a1: the refractive index of a negative meniscus lens on the most-object side in the first lens group.