Patent ID: 9625686
Date: 2017-04-18
CPC Classifications: G02B,Y10T

Claim:
1. A zooming optical system comprising, in 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; upon zooming from a wide-angle end state to a telephoto end state, a distance between said first lens group and said second lens group, a distance between said second lens group and said third lens group and a distance between said third lens group and said fourth lens group being respectively varied; said third lens group having, in order from the object side, a first segment group having positive refractive power and a second segment group; said second segment group being movable with a component of movement in a direction perpendicular to the optical axis; and the following conditional expressions being satisfied: where f1 denotes focal length of the entire first lens group, f2 denotes focal length of the entire second lens group, f3 denotes focal length of the entire third lens group, f4 denotes focal length of the entire fourth lens group, and at least a part of said second lens group is constructed to move in a direction of the optical axis during focusing.