Granted Patent B2

US 12,560,787 · App. 18/656,533 · Granted Feb 24, 2026

Inventors: Satoru Shibata (Yokohama, JP); Tomoyuki Sashima (Tokyo, JP)

Assignee: Nikon Corporation

G02B15/145113G02B15/145129G02B15/1461G02B15/173G02B27/646

Abstract

Claims (98)

1 . A zoom optical system comprising, in order from an object side:

a first lens group having positive refractive power;

a front-side lens group;

an intermediate lens group having positive refractive power; and

a rear-side lens group,

wherein

the front-side lens group is composed of one or more lens groups and has a negative lens group,

at least part of the intermediate lens group is a vibration-proof lens group that is movable with a displacement component in a direction orthogonal to an optical axis, and at least part of the intermediate lens group is a focusing lens group,

the rear-side lens group is composed of one or more lens groups,

upon zooming, a distance between the first lens group and the front-side lens group is changed, a distance between the front-side lens group and the intermediate lens group is changed, and a distance between the intermediate lens group and the rear-side lens group is changed, and

the following conditional expression is satisfied:

0.

2

⁢

0

<

(

-

fXn

)

/

fM

<

1.6

where

fM denotes a focal length of the intermediate lens group, and

fXn denotes a focal length of a lens group with a largest absolute value of refractive power in a negative lens group of the front-side lens group.

2 . The zoom optical system according to claim 1 , wherein the following conditional expression is satisfied:

0.5

<

❘

"\[LeftBracketingBar]"

fF

❘

"\[RightBracketingBar]"

/

fM

<

5.

where

fF denotes a focal length of the focusing lens group.

3 . The zoom optical system according to claim 1 , wherein the following conditional expression is satisfied:

0.01

<

dV

/

❘

"\[LeftBracketingBar]"

fV

❘

"\[RightBracketingBar]"

<

0.5

where

dV denotes a distance between the vibration-proof lens group and a lens disposed to an image side of the vibration-proof lens group in a telephoto end state on an optical axis, and

fV denotes a focal length of the vibration-proof lens group.

4 . The zoom optical system according to claim 1 , wherein the following conditional expression is satisfied:

0.01

<

dAB

/

❘

"\[LeftBracketingBar]"

fF

❘

"\[RightBracketingBar]"

<

0.5

where

fF denotes a focal length of the focusing lens group, and

dAB denotes a distance between the focusing lens group and a lens disposed to the object side of the focusing lens group on an optical axis, upon focusing on infinity in a telephoto end state.

5 . The zoom optical system according to claim 1 , wherein the vibration-proof lens group has positive refractive power.

6 . The zoom optical system according to claim 1 , wherein the focusing lens group has negative refractive power.

7 . The zoom optical system according to claim 1 , wherein the first lens group is moved with respect to an image surface upon zooming.

8 . The zoom optical system according to claim 1 , wherein the rear-side lens group is moved with respect to an image surface upon zooming.

9 . The zoom optical system according to claim 1 , wherein the front-side lens group consists of a second lens group having negative refractive power.

10 . The zoom optical system according to claim 1 , wherein the intermediate lens group has an aperture stop.

11 . An optical device comprising the zoom optical system according to claim 1 .

12 . A method for manufacturing a zoom optical system, comprising:

arranging a first lens group having positive refractive power, a front-side lens group, an intermediate lens group having positive refractive power, and a rear-side lens group in order from an object side,

the front-side lens group being composed of one or more lens groups and having a negative lens group,

at least part of the intermediate lens group being a vibration-proof lens group that is movable with a displacement component in a direction orthogonal to an optical axis, and at least part of the intermediate lens group being a focusing lens group,

the rear-side lens group being composed of one or more lens groups,

the arrangement being such that upon zooming, a distance between the first lens group and the front-side lens group is changed, a distance between the front-side lens group and the intermediate lens group is changed, and a distance between the intermediate lens group and the rear-side lens group is changed; and

satisfying the following conditional expression:

0.2

<

(

-

fXn

)

/

fM

<

1.6

where

fM denotes a focal length of the intermediate lens group, and

fXn denotes a focal length of a lens group with a largest absolute value of refractive power in a negative lens group of the front-side lens group.

Priority Claims (14)

Continuity (9)

References Cited (61)