# US 11,079,574 B2 · Zoom lens, optical apparatus, and a manufacturing method of the zoom lens

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- Number: US 11,079,574 B2
- Document ID: US11079574B2
- Status: Granted
- Kind: B2
- Application number: 16/666,896
- Filed: 2019-10-29
- Published: 2020-02-27
- Granted: 2021-08-03
- Earliest claimed: 2013-11-21
- Assignees: Nikon Corporation
- Applicants: Nikon Corporation
- Inventors: Keigo Koida
- Web page: https://patentgrep.com/patent/US11079574B2

## CPC

- G02B 15/144511: {arranged -+-+}
- G02B 5/005: {Diaphragms (for cameras G03B9/02)}
- G02B 15/177: having a negative front lens or group of lenses
- G02B 27/646: {compensating for small deviations, e.g. due to vibration or shake (movement of one or more optical elements for control of motion blur in cameras, projectors or printers G03B2205/0007; image stabilisation in cameras peculiar to the presence or use of an electronic image sensor H04N23/68)}
- G02B 13/18: with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration {(G02B13/002 takes precedence)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A zoom lens consists of, in order from an object, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens group having a positive refractive power. Zooming is performed by changing respective distances between the first and second lens groups, the second and third lens groups, and the third and fourth lens groups. The first lens group consists of, in order from an object, a negative lens, a negative lens and a positive lens, the second lens group consists of five lenses, and the third lens group consists of a bi-concave negative lens.

## Claims

### Claim 1

A zoom lens consisting of, in order from an object, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens group having a positive refractive power, and
zooming is performed by changing respective distances between the first and second lens groups, the second and third lens groups, and the third and fourth lens groups,
the first lens group consisting of, in order from an object, a negative lens, a negative lens and a positive lens,
the second lens group consisting of five lenses, and
the third lens group consisting of a bi-concave negative lens.

### Claim 2 (depends on 1)

The zoom lens according to claim 1, wherein the first lens group, the second lens group, and the third lens group are moved on an optical axis upon zooming.

### Claim 3 (depends on 1)

The zoom lens according to claim 1, wherein the following conditional expression is satisfied:
0.30<D3W/D3T<1.10
where D3W denotes an air interval between the third lens group and the fourth lens group in a wide-angle end state, and
D3T denotes an air interval between the third lens group and the fourth lens group in a telephoto end state.

### Claim 4 (depends on 1)

The zoom lens according to claim 1, wherein the fourth lens group consists of one lens.

### Claim 5 (depends on 1)

The zoom lens according to claim 1, wherein the first lens group consists of, in order from the object, a meniscus-shaped negative lens having a concave surface facing an image, a bi-concave negative lens, and a meniscus-shaped positive lens having a convex surface facing the object.

### Claim 6 (depends on 1)

The zoom lens according to claim 1, wherein the lenses of the second lens group are constituted by, in order from the object, a positive lens, a cemented lens of a bi-convex positive lens and a bi-concave negative lens, a single lens and a bi-convex positive lens, and
wherein an aperture stop is disposed between the positive lens and the cemented lens.

### Claim 7 (depends on 1)

The zoom lens according to claim 1, wherein the following conditional expression is satisfied:
0.50<M4/M3<1.00
where M3 denotes the amount of movement on the optical axis of the third lens group upon zooming from a wide-angle end state to a telephoto end state, and
M4 denotes the amount of movement on the optical axis of the fourth lens group upon zooming from the wide-angle end state to the telephoto end state.

### Claim 8 (depends on 1)

The zoom lens according to claim 1, wherein the following conditional expression is satisfied:
0.05<BFw/(fw2+ft2)1/2<0.50
where BFw denotes an air equivalent distance from a rear end lens surface of the zoom lens in a wide-angle end state to an image surface,
fw denotes a focal length of the zoom lens in the wide-angle end state, and
ft denotes a focal length of the zoom lens in a telephoto end state.

### Claim 9 (depends on 1)

The zoom lens according to claim 1, wherein the following conditional expression is satisfied:
1.00<Σdw/Σdt<2.00
where Σdw denotes a distance from a front end lens surface of the zoom lens to a rear end lens surface of the zoom lens in a wide-angle end state, and
Σdt denotes a distance from the front end lens surface of the zoom lens to the rear end lens surface of the zoom lens in a telephoto end state.

### Claim 10 (depends on 1)

The zoom lens according to claim 1, wherein the fourth lens group is composed of one lens, wherein
the following conditional expression is satisfied:
2.30<f4/fw<9.00
where f4 denotes a focal length of the fourth lens group, and
fw denotes a focal length of the zoom lens in a wide-angle end state.

### Claim 11 (depends on 1)

The zoom lens according to claim 1, wherein the following conditional expression is satisfied:
0.80<(−f1)/f2<1.50
where f1 denotes a focal length of the first lens group, and
f2 denotes a focal length of the second lens group.

### Claim 12 (depends on 1)

The zoom lens according to claim 1, wherein the second lens group comprises a positive lens closest to the object.

### Claim 13 (depends on 1)

The zoom lens according to claim 1, wherein the second lens group comprises, in order from the object, a positive lens, and a cemented lens composed of a positive lens and a negative lens.

### Claim 14 (depends on 1)

An optical apparatus including the zoom lens according to claim 1.

### Claim 15

A manufacturing method of a zoom lens consisting of, in order from an object, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens group having a positive refractive power,
the method comprising:
arranging the lens groups in a lens-barrel such that the first lens group, the second lens group, and the third lens group are moved on an optical axis to perform zooming by changing respective distances between the first and second lens groups, the second and third lens groups, and the third and fourth lens groups,
configuring the first lens group to consist of, in order from the object, a negative lens, a negative lens and a positive lens,
configuring the second lens group to consist of five lenses, and
configuring the third lens group to consist of a bi-concave negative lens.