Imaging lens and imaging apparatus equipped with the same

Patent metadata

Field	Value
Publication number	US-9494770-B2
Application number	US-201514627149-A
Country	US
Kind code	B2
Filing date	Feb 20, 2015
Priority date	Aug 24, 2012
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

An imaging lens consists of a front group and a rear group. The front group is composed of a lens having a negative meniscus shape with a convex surface on the object side, a negative lens, a negative lens, and a positive lens in order from the object side. The rear group is composed of a positive lens, a negative lens, a positive lens, and a positive lens in order from the object side. The imaging lens satisfies given conditional expressions.

First claim

What is claimed is:

1. An imaging lens, consisting essentially of a front group and a rear group in order from the object side, wherein:
the front group consists essentially of a negative meniscus lens with a convex surface on the object side, a negative lens, a negative lens, and a positive lens in order from the object side;
the rear group consists essentially of a positive lens, a negative lens, a positive lens, and a positive lens in order from the object side; and
the imaging lens satisfies conditional expressions (1) and (4) given below:
0.42< f/f 2<1.0  (1), and

−0.065< f/f 1<0.10  (4)

where
f: focal length of the entire system,
f1: focal length of the front group, and
f2: focal length of the rear group.

2. The imaging lens as claimed in claim 1 , wherein the imaging lens satisfies a conditional expression (1′) given below:
0.45< f/f 2<1.0  (1′).

3. The imaging lens as claimed in claim 1 , wherein the imaging lens satisfies a conditional expression (2) given below:
0.3<| R 6 a/f|< 1.6  (2)

where
R6a: radius of curvature of the object side surface of the negative lens in the rear group.

4. The imaging lens as claimed in claim 1 , wherein a stop is provided between the front group and the rear group.

5. The imaging lens as claimed in claim 4 , wherein the imaging lens satisfies a conditional expression (3) given below:
1.0< Dab/f< 5.1  (3)

where
Dab: distance on the optical axis between the most object side lens surface in the front group to the most object side lens surface in the rear group.

6. The imaging lens as claimed in claim 1 , wherein the imaging lens satisfies a conditional expression (1″) given below:
0.5< f/f 2<0.8  (1″).

7. The imaging lens as claimed in claim 3 , wherein the imaging lens satisfies a conditional expression (2′) given below:
0.8<| R 6 a/f|< 1.5  (2′).

8. The imaging lens as claimed in claim 5 , wherein the imaging lens satisfies a conditional expression (3′) given below:
3.0< Dab/f< 4.9  (3′).

9. The imaging lens as claimed in claim 1 , wherein the imaging lens satisfies a conditional expression (4′) given below:
−0.02< f/f 1<0.02  (4′).

10. An imaging apparatus equipped with the imaging lens as claimed in claim 1 .

Assignees

• Fujifilm Corp

Inventors

• Sun Ping
• Tsutsumi Katsuhisa
• Cho Michio

Classifications

• G02B13/0045

  having five or more lenses · CPC title

• G02B13/04 Primary

  Reversed telephoto objectives · CPC title

• G02B9/62

  having six components only · CPC title

• G02B9/04

  having two components only · CPC title

• G02B9/64

  having more than six components · CPC title