Patent ID: 7453651

Claim:
A zoom lens comprising, sequentially from an object side thereof, a first lens elements group, a second lens elements group and a third lens element group, wherein the first lens elements group having a negative refraction power as a whole and being made up by disposing a first lens element which is a lens having a negative refraction power (hereinafter, referred to as a negative lens) and a second lens element which is a lens having a positive refraction power (hereinafter, referred to as a positive lens) and which constitutes a meniscus lens which is convex on an object side surface thereof, the second lens elements group having a positive refraction power as a whole and being made up by disposing a third lens element which is a positive lens, a fourth lens element which is a positive lens, a fifth lens element which is a negative lens and which constitutes a meniscus lens which is convex on an object side surface thereof and a sixth lens element which is a positive lens, and the third lens element group having a negative refraction power as a whole and being made up by disposing a seventh lens element which is a negative lens and which constitutes a meniscus lens which is convex on an image side surface thereof, wherein a variable power is realized by shifting the positions of the first lens elements group and the second lens elements group in a direction of an optical axis thereof, or so shifting, in addition to the first lens elements group and the second lens elements group, the position of the third lens element group, and wherein the zoom lens satisfies the following conditional expression (1) with respect to the power that the first lens elements group possesses, the following conditional expression (2) with respect to the power that the third lens element group possesses, and the following conditional expression (3) with respect to the size of a whole lens system −0.7 <f w /f I <−0.30 (1) −0.5 <f w /f III <0 (2) 5.5 <TL w /f w <7.0 (3) where, f w : composite focal length of the whole lens system at a wide-angle end f I : composite focal length of the first lens elements group f III : composite focal length of the third lens element group TL w : distance from an object side surface of the first lens element making up the first lens elements group to an image plane at the wide-angle end (where, a parallel plane glass portion is converted into an air space distance).