Patent ID: 8503100

Claim:
A zoom lens comprising: a first lens group having a positive refractive power; a second lens group having a negative refractive power; a third lens group having a positive refractive power; and a fourth lens group having a positive refractive power and consists of one lens, wherein the first lens group, the second lens group, the third lens group, and the fourth lens group are sequentially arranged from an object side to an image surface side, while zooming from a wide-angle position to a telephoto position, the first lens group is moved in such a way that the distance between the first lens group and the second lens group is widened, the second lens group is moved along a trajectory convex toward the image surface side, the third lens group is moved from the image surface side to the object side, and the fourth lens group is moved along a trajectory convex toward the object side, and the zoom lens satisfies the following inequalities: ν d 1ave>68.2, and Nd 1ave>1.53 where νd1ave is the average of Abbe numbers of positive lenses belonging to the first lens group, and Nd1ave is the average of refractive indexes of the positive lenses belonging to the first lens group.