Patent ID: 7136231
Filing Date: 2006-11-14
Classification: G02B

Abstract:
1. A zoom lens system comprising, in order from an object: 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; each of the first lens group through the fourth lens group moving such that; when the state of lens group positions varies from a wide-angle end state to a telephoto end state; a distance between the first lens group and the second lens group increases; a distance between the second lens group and the third lens group decreases; and a distance between the third lens group and the fourth lens group decreases; the third lens group including at least two sub-lens groups having positive refractive power; an image being shifted by moving either of the two sub-lens groups as a shift lens group perpendicularly to the optical axis; and wherein the following conditional expression is satisfied: where DT denotes an air space between the most image side lens surface of the first lens group and the most object side lens surface of the second lens group in the telephoto end state, and ft denotes the focal length of the zoom lens system in the telephoto end state.