Optical system and image pickup apparatus having the same

Patent metadata

Field	Value
Publication number	US-2024302626-A1
Application number	US-202418596299-A
Country	US
Kind code	A1
Filing date	Mar 5, 2024
Priority date	Mar 8, 2023
Publication date	Sep 12, 2024
Grant date	—

Abstract

An optical system includes, in order from an object side to an image side, a first lens unit having positive refractive power, a second lens unit having positive refractive power, a third lens unit, a fourth lens unit having positive refractive power, and a fifth lens unit having negative refractive power. During focusing from infinity to a close distance, a distance between adjacent lens units changes and the second lens unit and the fourth lens unit move toward the object side. At least one of the second lens unit and the fourth lens unit includes two or more lenses. The first lens unit includes two or more negative lenses. A predetermined inequality is satisfied.

First claim

What is claimed is:

1 . An optical system comprising, in order from an object side to an image side:
a first lens unit having positive refractive power; a second lens unit having positive refractive power; a third lens unit; a fourth lens unit having positive refractive power; and a fifth lens unit having negative refractive power, wherein during focusing from infinity to a close distance, a distance between adjacent lens units changes and the second lens unit and the fourth lens unit move toward the object side, wherein at least one of the second lens unit and the fourth lens unit includes two or more lenses, wherein the first lens unit includes two or more negative lenses, wherein the following inequality is satisfied:

0
.
0

⁢
4
⁢
0

<

T
⁢
4
/
TTL

<

0
.
5

⁢
9
⁢
0

where TTL is an overall optical length that is a distance on an optical axis from a lens surface closest to an object to an image plane of the optical system in an in-focus state at infinity, and T4 is a thickness on the optical axis of the fourth lens unit.

2 . The optical system according to claim 1 , wherein for focusing from infinity to the close distance, the first lens unit, the third lens unit, and the fifth lens unit are fixed relative to an image plane.

3 . The optical system according to claim 1 , further comprising an aperture stop between the second lens unit and the fourth lens unit.

4 . The optical system according to claim 1 , wherein the following inequalities are satisfied:

0.3
<

f
⁢
4
/
f

<

4
.
8

⁢
0

0.7
<

f
⁢
2
/
f

<

2
⁢

6
.
8

⁢
0

where f is a focal length of the optical system in an in-focus state at infinity, f2 is a focal length of the second lens unit, and f4 is a focal length of the fourth lens unit.

5 . The optical system according to claim 1 , wherein the following inequality is satisfied:

0
.
0

⁢
5

<

f
⁢
4
/
f
⁢
2

<
1.5

where f2 is a focal length of the second lens unit, and f4 is a focal length of the fourth lens unit.

6 . The optical system according to claim 1 , wherein the following inequality is satisfied:

0
.
0

⁢
0
⁢
8

<

D
⁢
12
/
DT

<

0
.
2

⁢
1
⁢
0

where DT is a distance on the optical axis from a lens surface on the object side of the first lens unit to a lens surface on the image side of a lens unit disposed closest to the image plane in the in-focus state at infinity, and D12 is a distance on the optical axis from a lens surface on the image side of the first lens unit to a lens surface on the object side of the second lens unit in the in-focus state at infinity.

7 . The optical system according to claim 1 , wherein the following inequality is satisfied:

0
.
0

⁢
2
⁢
0

<

D
⁢
34
/
DT

<

0
.
5

⁢
3
⁢
0

where DT is a distance on the optical axis from a lens surface on the object side of the first lens unit to a lens surface on the image side of a lens unit disposed closest to the image plane in the in-focus state at infinity, and D34 is a distance on the optical axis from a lens surface on the image side of the third lens unit to a lens surface on the object side of the fourth lens unit in the in-focus state at infinity.

8 . The optical system according to claim 1 , wherein the following inequality is satisfied:

0
.
0

⁢
0
⁢
4

<

T
⁢
2
/
TTL

<

0
.
1

⁢
2
⁢
0

where T2 is a thickness on the optical axis of the second lens unit.

9 . The optical system according to claim 1 , wherein the following inequality is satisfied:

Assignees

• Canon Kk

Inventors

• Ode Takashi
• Hatada Takahiro

Classifications

• G02B15/145115 Primary

  arranged ++++- · CPC title

• G02B15/1451 Primary

  the first group being positive · CPC title

• G02B9/60 Primary

  having five components only · CPC title