Patent ID: 6204976
Filing Date: 2001-03-20
Classification: G02B

Abstract:
A zoom lens comprising, in sequential order from the object side:a first lens group having negative refractive power and that is fixed in position during zooming;a second lens group having positive refractive power;a third lens group having positive refractive power; anda fourth lens group having positive refractive power that is fixed in position during zooming;wherein, the second lens group and the third lens group move in a mutual relationship for continuous zooming and correction for what otherwise would be a shifting of the image plane caused by zooming, andthe following Condition is satisfied.beta..sub.2.times..beta..sub.3 >-2.2where.beta..sub.2 is the lateral magnification of the second lens group at the wide-angle end for an object at infinity, and.beta..sub.3 is the lateral magnification of the third lens group at the wide-angle end for an object at infinity.