Zoom lens and imaging apparatus

Patent metadata

Field	Value
Publication number	US-12007540-B2
Application number	US-202117188021-A
Country	US
Kind code	B2
Filing date	Mar 1, 2021
Priority date	Mar 11, 2020
Publication date	Jun 11, 2024
Grant date	Jun 11, 2024

Abstract

A zoom lens consists of, in order from an object side to an image side: a first lens group having a positive refractive power; a second lens group having a negative refractive power; a third lens group having a positive refractive power; a fourth lens group having a positive refractive power; a fifth lens group having a negative refractive power; and a sixth lens group having a positive refractive power. During zooming from the wide angle end to the telephoto end, the distance between the adjacent lens groups in the optical axis direction changes, and the third lens group and the fifth lens group move integrally along the optical axis.

First claim

What is claimed is:

1. A zoom lens consisting of, in order from an object side to an image side:
a first lens group having a positive refractive power; a second lens group having a negative refractive power; a third lens group having a positive refractive power; a fourth lens group having a positive refractive power; a fifth lens group having a negative refractive power; and a sixth lens group having a positive refractive power,
wherein during zooming from a wide angle end to a telephoto end, the third lens group and the fifth lens group move integrally along an optical axis and distances between adjacent lens groups in an optical axis direction change, and
assuming that
a focal length of the sixth lens group is f6, and
a focal length of the first lens group is f1,
Conditional Expression (5) is satisfied, which is represented by
0.25< f 6/ f 1<1  (5).

2. The zoom lens according to claim 1 , wherein the fourth lens group moves during focusing.

3. The zoom lens according to claim 1 , wherein assuming that
a focal length of the third lens group is f3, and
a focal length of the fourth lens group is f4,
Conditional Expression (1) is satisfied, which is represented by
0.12< f 3/ f 4<1.24  (1).

4. The zoom lens according to claim 1 , wherein assuming that
a focal length of the second lens group is f2, and
a focal length of the fourth lens group is f4,
Conditional Expression (2) is satisfied, which is represented by
−1< f 2/ f 4<−0.12  (2).

5. The zoom lens according to claim 1 , wherein assuming that
a focal length of the second lens group is f2, and
a focal length of the first lens group is f1,
Conditional Expression (3) is satisfied, which is represented by
−0.3< f 2/ f 1<−0.07  (3).

6. The zoom lens according to claim 1 , wherein assuming that
a focal length of the fifth lens group is f5, and
a focal length of the fourth lens group is f4,
Conditional Expression (4) is satisfied, which is represented by
−0.79< f 5/ f 4<−0.1  (4).

7. The zoom lens according to claim 1 , wherein assuming that
a distance on the optical axis from a lens surface closest to the object side in the first lens group to an image plane at the telephoto end is Xt1,
a distance on the optical axis from the lens surface closest to the object side in the first lens group to the image plane at the wide angle end is Xw1,
a distance on the optical axis from a lens surface closest to the object side in the second lens group to the image plane at the telephoto end is Xt2,
a distance on the optical axis from the lens surface closest to the object side in the second lens group to the image plane at the wide angle end is Xw2, and
a focal length of the first lens group is f1,
Conditional Expression (6) is satisfied, which is represented by
0.35<{( Xt 1− Xw 1)−( Xt 2− Xw 2)}/ f 1<0.55  (6).

8. The zoom lens according to claim 1 , wherein assuming that
a distance on the optical axis from a lens surface closest to the image side in the third lens group to a lens surface closest to the object side in the fifth lens group is Db35, and
a focal length of the fourth lens group is f4,
Conditional Expression (7) is satisfied, which is represented by
0.11< Db 35/ f 4<0.96  (7).

9. The zoom lens according to claim 1 , wherein assuming that
a distance on the optical axis from a lens surface closest to the object side in the third lens group to a lens surface closest to the image side in the fifth lens group is D3f5r, and
a distance on the optical axis from a lens surface closest to the object side in the fourth lens group to a lens surface closest to the image side in the fourth lens group is T4,
Conditional Expression (8) is satisfied, which is represented by
3.06< D 3 f 5 r/T 4<12.74  (8).

10. The zoom lens according to claim 1 ,
wherein the third lens group includes a positive lens closest to the object side, and
assuming that
a focal length of the positive lens closest to the object side in the third lens group is f31, and
a focal length of the third lens group is f3,

Conditional Expression (9) is satisfied, which is represented by
0.5< f 31/ f 3<2.8  (9).

11. The zoom lens according to claim 1 ,
wherein the third lens group includes a positive lens closest to the object side, and
assuming that an Abbe number of the positive lens closest to the object side in the third lens group based on a d line is ν31,
Conditional Expression (10) is satisfied, which is represented by
45<ν31<97  (10).

12. The zoom lens according to claim 1 ,
wherein the first lens group consists of, in order from the object side to the image side, one negative lens and two positive lenses, and
assuming that an average value of Abbe numbers of the two positive lenses of the first lens group based on a d line is ν1pave,
Conditional Expression (11) is satisfied, which is represented by
60<ν1pave<97  (11).

13. The zoom lens according to claim 1 , wherein the third lens group consists of, in order from the object side to the image side, one single lens having a positive refractive power, and a cemented lens in which one negative lens and one positive lens are cemented in order from the object side.

14. The zoom lens according to claim 1 , wherein the fourth lens group includes a cemented lens in which one negative lens and one positive lens are cemented in order from the object side.

15. The zoom lens according to claim 1 , wherein the sixth lens group consists of a single lens having a positive refractive power.

16. The zoom lens according to claim 1 , wherein during zooming from the wide angle end to the telephoto end, the first lens group, the second lens group, the third lens group, the fourth lens group, and the fifth lens group move along the optical axis, and the sixth lens group remains stationary with respect to an image plane.

17. An imaging apparatus comprising the zoom lens according to claim 1 .

18. A zoom lens consisting of, in order from an object side to an image side: a first lens group having a positive refractive power; a second lens group having a negative refractive power; a third lens group having a positive refractive power; a fourth lens group having a positive refractive power; a fifth lens group having a negative refractive power; and a sixth lens group having a positive refractive power,
wherein during zooming from a wide angle end to a telephoto end, the third lens group and the fifth lens group move integrally along an optical axis and distances between adjacent lens groups in an optical axis direction change, and
the fifth lens group consists of two negative lenses and one positive lens.

19. A zoom lens consisting of, in order from an object side to an image side: a first lens group having a positive refractive power; a second lens group having a negative refractive power; a third lens group having a positive refractive power; a fourth lens group having a positive refractive power; a fifth lens group having a negative refractive power; and a sixth lens group having a positive refractive power,
wherein during zooming from a wide angle end to a telephoto end, the third lens group and the fifth lens group move integrally along an optical axis and distances between adjacent lens groups in an optical axis direction change, and
all lens surfaces of the sixth lens group have a shape convex toward the image side.

Assignees

• Fujifilm Corp

Inventors

• Noda Taiga
• Nagami Ryosuke

Classifications

• G02B15/20

  having an additional movable lens or lens group for varying the objective focal length · CPC title

• G02B27/0025

  for optical correction, e.g. distorsion, aberration · CPC title

• G02B13/006

  at least one element being a compound optical element, e.g. cemented elements · CPC title

• G02B13/0045

  having five or more lenses · CPC title

• G02B13/0015

  characterised by the lens design · CPC title