Patent ID: 6181484
Filing Date: 2001-01-30
Classification: G02B

Abstract:
A compact two-group wide-angle zoom lens consisting, successively from an object side, a positive first lens group G1 having at least one aspheric surface and a negative second lens group G2, in which a distance between said lens groups is changed to attain a variable power;wherein said first lens group G1 consists of G1A group comprising, successively from the object side, a negative lens having a meniscus form with a concave surface directed onto the object side and a positive lens having a meniscus form with a convex surface directed onto the object side, and G1B group having at least one biconvex lens;wherein said second lens group G2 comprises, successively from the object side, a meniscus lens having an aspheric surface with a concave surface directed onto the object side, a positive lens having a convex surface directed onto the object side, and a negative lens having a concave surface directed onto the object side;wherein a stop is disposed between said G1A and G1B groups; andwherein said zoom lens satisfies the following conditional expressions:-0.6<fw/f'g1a<1.4 (1)0.07<Dab/f'w<0.25 (2)wherein:f'w is the rear-side focal length of the whole lens system at the wide-angle end;f'g1a is the focal length of the G1A group;Dab is the air space between the G1A group and the G1B group.