Patent ID: 8284496
Filing Date: 2012-10-09
Classification: G02B

Abstract:
1. A zoom optical system constituted by a plurality of lens groups and in which magnification is changed by properly changing distances between the lens groups, wherein a positive first lens group, a negative second lens group, a positive third lens group, and a positive fourth lens group are arranged in that order from the object side, the first lens group consists of only one lens element, the second lens group includes, in order from the object side, a negative single lens, a negative cemented lens, and a positive single lens, and the following condition (1) is satisfied: where ΔD w-w10 denotes the variation in the distance between the first and second lens groups in changing from the wide angle end position to the position in which the focal length is ten times or more as large as that in the wide angle end position, and L t denotes the total length of the optical system in the telephoto end position.