Achromatic lens and zoom lens using the same
AssigneeFuji Photo Optical Co., Ltd.
InventorHitoshi Miyano
Life of this patent
Estimating the term…
Abstract
In a zoom lens comprising first to fourth lens groups, the second lens group comprises two meniscus lenses and an achromatic lens. The achromatic lens comprises a cemented lens having a negative refracting power as a whole, and a lens having a positive refracting power with a convex surface directed onto the object side. The cemented lens comprises a meniscus lens or plane-convex lens having a positive refracting power with a convex surface or plane directed onto the object side, and a lens having a negative refracting power.
Claims7
A zoom lens comprising, successively from an object side, a first lens group, fixed upon zooming, having a positive refracting power;
- a second lens group, movable upon zooming, having a negative refracting power;
- a third lens group, having a negative refracting power, for correcting a fluctuation of an image surface upon zooming;
- and a fourth lens group, fixed upon zooming, having a positive refracting power;
- wherein said second lens group comprises, successively from the object side,
- two meniscus lenses each having a negative refracting power with a convex surface directed onto the object side;
- and
- an achromatic lens comprising, successively from the object side, a cemented lens having a negative refracting power as a whole, and a lens having a positive refracting power with a convex surface directed onto the object side;
- said cemented lens comprising, successively from the object side, a meniscus lens or plane-convex lens having a positive refracting power with a convex surface or plane directed onto the object side, and a lens having a negative refracting power.
An achromatic lens comprising, successively from the object side, a cemented lens having a negative refracting power as a whole, and a lens having a positive refracting power with a convex surface directed onto the object side;
- said cemented lens comprising, successively from the object side, a meniscus lens or plane-convex lens having a positive refracting power with a convex surface or plane directed onto the object side, and a lens having a negative refracting power.
Dependencies are inferred from the claim text.