Patent ID: 6011658
Filing Date: 2000-01-04
Classification: G02B

Abstract:
A compact zoom lens system for imaging an object in an image plane, the lens system, when viewed from the object, comprising:a first lens group with a positive refractive power; anda second lens group with a negative refractive power;wherein the magnification of the lens system is changed from a wide angle position to a telephoto position by moving the first lens group and the second lens group jointly along the optical axis of the lens system towards the object,wherein0.45<L.sub.w /f.sub.t <0.55,2.5<f.sub.t /f.sub.w (.phi.m)<3.0,4.3<m2t<5,wherein L.sub.w is the distance between a front surface of the lens which is closest to the object, of the first lens group, and the image plane in the wide angle position , f.sub.t is the focal length of the compact zoom lens system in the telephoto position, f.sub.w is the focal length of the compact zoom lens system in the wide angle position, .phi.m is the zoom ratio, and m2t is the magnification of the second lens group in the telephoto position.