Patent ID: 6995923
Filing Date: 2006-02-07
Classification: G02B

Abstract:
1. A zoom lens comprising, arranged along an optical axis in order from the object side: a first lens group having negative refractive power and that includes only one or two lens components; a second lens group having positive refractive power and that includes only one lens component; a third lens group having negative refractive power and that includes only one lens component; wherein the second lens group and the third lens group move along the optical axis during zooming; and the following conditions are satisfied: where ft is the focal length of the zoom lens at the telephoto end, fw is the focal length of the zoom lens at the wide-angle end, MTL is the longest distance from the most object-side lens surface to the image plane, when focused on an object at infinity, for any zoom position from the wide-angle end through the telephoto end, and Bfw is the back focal length of the zoom lens at the wide-angle end.