Image-capturing lens
AssigneeFuji Photo Optical Co., Ltd.
InventorYoshikazu Shinohara
Life of this patent
Estimating the term…
Abstract
An image-capturing lens is formed of front and rear lens groups having negative and positive refractive power, respectively, in order from the object side. The rear lens group is formed of, in relative sequential order from the most object side of the rear lens group, a biconvex lens element that is cemented to a biconcave lens element, a biconvex lens element, and a biconvex lens element. A specified condition is satisfied so as to make the cemented lens of the rear lens group insensitive to de-centering errors which may occur either in making the cemented lens or in assembling the image-capturing lens.
Claims5
An image-capturing lens comprising, in order from the object side:
- a front lens group having negative refractive power;
- and
- a rear lens group having positive refractive power and formed of the following lens elements, in sequential order from the most object side of the rear lens group,
- a cemented lens formed of a first lens element that is biconvex and cemented to a second lens element that is biconcave,
- a third lens element that is biconvex;
- and
- a fourth lens element that is biconvex;
- said rear lens group satisfying the following condition
- |β5+β6|≦0.3
- where
- β5 is defined as equal to the product of (1−b5) (b6) (b7) (b8), and
- β6 is defined as the product of (1−b6) (b7) (b8),
- with
- b5 being the transverse magnification of the first lens element in the rear lens group,
- b6 being the transverse magnification of the second lens element in the rear lens group,
- b7 being the transverse magnification of the third lens element in the rear lens group, and
- b8 being the transverse magnification of the fourth lens element in the rear lens group.
Dependencies are inferred from the claim text.