Zoom lens system, optical apparatus and method for manufacturing zoom lens system

Patent metadata

Field	Value
Publication number	US-9513471-B2
Application number	US-201414270270-A
Country	US
Kind code	B2
Filing date	May 5, 2014
Priority date	Mar 8, 2010
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

In a zoom lens system, an optical apparatus, and a manufacturing method, there are provided, in order from an object side: a first lens group having positive power, a second lens group having negative power, a third lens group having positive power, a fourth lens group having negative power, a fifth group having positive power, and an aperture stop disposed to an image side of the second lens group. Upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens and second lens groups increases, a distance between the second and third lens groups decreases, a distance between the third and fourth lens groups varies, and a distance between the fourth and fifth lens groups varies. With given conditions being satisfied, high optical performance with suppressing variation in aberrations are achieved.

First claim

What is claimed is:

1. A zoom lens system comprising, in order from an object side along an optical axis:
a first lens group having positive refractive power;
a second lens group having negative refractive power; and
a third lens group having positive refractive power,
upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group increasing, a distance between the second lens group and the third lens group decreasing,
the third lens group including, in order from the object side along the optical axis, a first sub-lens group having positive refractive power, a second sub-lens group having negative refractive power, and a third sub-lens group,
upon zooming from the wide-angle end state to the telephoto end state, a distance between the first sub-lens group and the second sub-lens group varying, and a distance between the second sub-lens group and the third sub-lens group varying, and
the first sub-lens group including, in order from the object side along the optical axis, a first positive lens, a second positive lens and a cemented lens,
wherein the cemented lens includes, in order from the object side along the optical axis, a third positive lens and a negative lens,
wherein the following conditional expression is satisfied:
35.0<ν d 31−ν d 34<70.0

where νd31 denotes an Abbe number of the first positive lens at d-line, and νd34 denotes an Abbe number of the negative lens at d-line,
wherein the following conditional expression is satisfied:
40.0<ν d 32−ν d 34<65.0

where νd31 denotes an Abbe number of the second positive lens at d-line, and νd34 denotes the Abbe number of the negative lens at d-line,
wherein the following conditional expression is satisfied:
40.0<ν d 33−ν d 34<70.0

where νd33 denotes an Abbe number of the third positive lens at d-line, and νd34 denotes the Abbe number of the negative lens at d-line, and
wherein the third positive lens has a biconvex shape and the negative lens has a negative meniscus shape.

2. The zoom lens system according to claim 1 , wherein the following conditional expression is satisfied:
35.0<(ν d 31+ν d 32+ν d 33)/3−ν d 34<70.0

where νd31 denotes the Abbe number of the first positive lens at d-line, νd32 denotes the Abbe number of the second positive lens at d-line, νd33 denotes the Abbe number of the third positive lens at d-line, and νd34 denotes the Abbe number of the negative lens at d-line.

3. The zoom lens system according to claim 1 , wherein the following conditional expression is satisfied:
0.80< f 3 A /(− f 3 B )<1.30

where f3A denotes a focal length of the first sub-lens group, and f3B denotes a focal length of the second sub-lens group.

4. The zoom lens system according to claim 1 , wherein the following conditional expression is satisfied:
0.50 <f 32 /f 31<10.00

where f31 denotes a focal length of the first positive lens, and f32 denotes a focal length of the second positive lens.

5. The zoom lens system according to claim 1 , wherein the following conditional expression is satisfied:
0.50< r 32 a/r 31 a< 10.00

where r31a denotes a radius of curvature of the object side surface of the first positive lens, and r32a denotes a radius of curvature of the object side surface of the second positive lens.

6. The zoom lens system according to claim 1 , wherein the first positive lens has a biconvex shape.

7. The zoom lens system according to claim 1 , wherein the second positive lens has a biconvex shape.

8. The zoom lens system according to claim 1 , wherein upon zooming from the wide-angle end state to the telephoto end state, the distance between the first sub-lens group and the second sub-lens group increases, and the distance between the second sub-lens group and the third sub-lens group decreases.

9. The zoom lens system according to claim 1 , wherein the third sub-lens group has positive refractive power.

10. The zoom lens system according to claim 1 , wherein an aperture stop is disposed to the image side of the second lens group.

11. The zoom lens system according to claim 1 , wherein an aperture stop is disposed between the second lens group and the third lens group.

12. The zoom lens system according to claim 1 , wherein an aperture stop is included, and upon zooming from the wide-angle end state to the telephoto end state, the aperture stop moves in a body with the first sub-lens group.

13. An optical apparatus equipped with the zoom lens system according to claim 1 .

14. A method for manufacturing a zoom lens system including, in order from an object side along an optical axis, a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power,
the method comprising steps of:
disposing the first lens group, the second lens group and the third lens group such that upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group increases, and a distance between the second lens group and the third lens group decreases;
disposing, in order from the object side along the optical axis, a first sub-lens group having positive refractive power, a second sub-lens group having negative refractive power, and a third sub-lens group into the third lens group such that upon zooming from a wide-angle end state to a telephoto end state, a distance between the first sub-lens group and the second sub-lens group varies, and a distance between the second sub-lens group and the third sub-lens group varies;
disposing, in order from the object side along the optical axis, a first positive lens, a second positive lens, and a cemented lens into the first sub-lens group, wherein the cemented lens includes, in order from the object side along the optical axis, a third positive lens and a negative lens; and
satisfying the following conditional expressions:
35.0<ν d 31−ν d 34<70.0

where νd31 denotes an Abbe number of the first positive lens at d-line, and νd34 denotes an Abbe number of the negative lens at d-line,
40.0<ν d 32−ν d 34<65.0

where νd32 denotes an Abbe number of the second positive lens at d-line, and νd34 denotes the Abbe number of the negative lens at d-line, and
40.0<ν d 33−ν d 34<70.0

where νd33 denotes an Abbe number of the third positive lens at d-line, and νd34 denotes the Abbe number of the negative lens at d-line, and
wherein the third positive lens has a bioconvex shape and the negative lens has a negative meniscus shape.

15. The method according to claim 14 , further comprising steps of:
satisfying the following conditional expression:
35.0<(ν d 31+ν d 32+ν d 33)/3−ν d 34<70.0

where νd31 denotes the Abbe number of the first positive lens at d-line, νd32 denotes the Abbe number of the second positive lens at d-line, νd33 denotes the Abbe number of the third positive lens at d-line, and νd34 denotes the Abbe number of the negative lens at d-line.

16. The method according to claim 14 , further comprising a step of:
satisfying the following conditional expression:
0.80< f 3 A /(− f 3 B )<1.30

where f3A denotes a focal length of the first sub-lens group, and f3B denotes a focal length of the second sub-lens group.

17. A zoom lens system comprising, in order from an object side along an optical axis:
a first lens group having positive refractive power;
a second lens group having negative refractive power; and
a third

Assignees

• Nikon Corp

Inventors

• Yokoi Norikazu
• Obama Akihiko

Classifications

• Y10T29/49826

  Assembling or joining · CPC title

• G02B15/16 Primary

  with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group (G02B15/22 takes precedence) · CPC title

• G02B15/173

  arranged +-+ · CPC title

• G02B15/14

  by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective · CPC title

• G02B15/143105

  arranged +-+ · CPC title