Patent ID: 6101045
Filing Date: 2000-08-08
Classification: G02B

Abstract:
A lens group provided within one of a positive and negative two lens group zoom lens system and a positive, positive and negative three lens group zoom lens system having a positive refractive power, said lens group comprising, from an object side:positive lens unit which is moved forward to the object side upon focusing for a close object; anda positive meniscus lens element convex to the object side moveable toward the object side in focusing for a close object, and wherein the following condition is fulfilled: ##EQU12## wherein DA is a movement amount of the positive lens unit in focusing and DB is a movement amount of the positive lens element in focusing;wherein the positive lens unit and the positive lens element are separated from each other,wherein a distance between said positive lens unit and said positive meniscus lens element varies upon focusing for a close object while said distance is fixed upon zooming, andwherein said positive lens element fulfills the following conditions: ##EQU13## wherein r1 is a radius of curvature of an object side surface of the positive lens element and r2 is a radius of curvature of an image side surface of the positive lens element.