| 摘要 |
PROBLEM TO BE SOLVED: To obtain a zoom lens which is suitable to a micro reader printer. etc., which has a constant distance between object images and high optical performance. SOLUTION: This zoom lens has two lens groups which are a 1st group with negative refracting power and a 2nd group with positive refracting power in order from the enlargement side and the power is varied by varying the interval between both the lens groups; and the 2nd group has two groups which are a group 2A with positive refracting power and a group 2B with negative refracting power. The group 2A is composed of a positive lens L21, a cemented lens L2a of a positive lens L22 and a negative lens L23, and a positive lens L24 and the group 2B is composed of a meniscus negative lens L24 which is convex to the enlargement side, a biconvex positive lens L26, a cemented lens L2b of a meniscus positive lens L27 which is convex to the image-plane side and a meniscus negative lens L28 which is convex to the image-plane side, a meniscus negative lens L29 which is concave to the enlargement side, and a positive lens L30 which is convex to the enlargement side.
|
