Zoom lens and image pickup apparatus having the same

Patent metadata

Field	Value
Publication number	US-9939634-B2
Application number	US-201515316964-A
Country	US
Kind code	B2
Filing date	Jun 4, 2015
Priority date	Jun 10, 2014
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

To obtain a zoom lens easily performing image blur correction and maintaining optical performance while performing image blur correction while restricting an increase in size of the lens. A zoom lens including, in order from an object side: a positive first unit; a negative second unit; a positive third unit; and a rear group that has one or more units. Spacings between adjacent units change during zooming. First and second correction systems rotatable about first and second centers on or in the vicinity of an optical axis during blur correction are respectively constituted by at least a part of the second unit and at least a part of an optical system disposed on image side of the second unit. The first and second centers are on image side of a surface vertex of the respective first and second correction systems closest to the object side.

First claim

The invention claimed is:

1. A zoom lens comprising, in order from an object side to an image side:
a first lens unit having a positive refractive power;
a second lens unit having a negative refractive power;
a third lens unit having a positive refractive power; and
a rear lens group that has one or more lens units,
wherein spacings between lens units adjacent to each other change during zooming,
wherein at least of a part of the second lens unit constitutes a first correction lens system that is rotatable about a first center of rotation, which is one point on an optical axis or in the vicinity of the optical axis, during image blur correction,
wherein at least of a part of an optical system disposed on the image side of the second lens unit constitutes a second correction lens system that is rotatable about a second center of rotation, which is one point on an optical axis or in the vicinity of the optical axis, during image blur correction,
wherein the first center of rotation is positioned on the image side of a surface vertex of a lens surface of the first correction lens system closest to the object side, and
wherein the second center of rotation is positioned on the image side of a surface vertex of a lens surface of the second correction lens system closest to the object side.

2. The zoom lens according to claim 1 , wherein a position of the first center of rotation is different from a position of the second center of rotation.

3. The zoom lens according to claim 1 , wherein image blur correction at a wide-angle end is performed by rotating the first correction lens system, and image blur correction at a telephoto end is performed by rotating the first correction lens system and the second correction lens system.

4. The zoom lens according to claim 1 , wherein image blur correction at a wide-angle end is performed by rotating the second correction lens system, and image blur correction at a telephoto end is performed by rotating the first correction lens system.

5. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied,
8.5< RA/dA< 20.0,
where RA represents a distance from a surface vertex of a lens surface of the first correction lens system close to the object side to the first center of rotation and dA represents a thickness of the first correction lens system on the optical axis.

6. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied,
0.3< RB/dB< 10.5,
where RB represents a distance from a surface vertex of a lens surface of the second correction lens system close to the object side to the second center of rotation and dB represents a thickness of the second correction lens system on the optical axis.

7. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied,
7.5<| RA/fA|< 22.5,
where RA represents a distance from a surface vertex of a lens surface of the first correction lens system close to the object side to the first center of rotation and fA represents a focal length of the first correction lens system.

8. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied,
0.3<| RB/fB|< 4.5,
where RB represents a distance from a surface vertex of a lens surface of the second correction lens system close to the object side to the second center of rotation and fB represents a focal length of the second correction lens system.

9. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied,
0.07<| fA/f 1|<0.25,
where fA represents that a focal length of the first correction lens system and f1 represents a focal length of the first lens unit.

10. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied,
0.19<| fB/f 1|<0.70,
where fB represents a focal length of the second correction lens system and f1 represents a focal length of the first lens unit.

11. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied,
0.02< fW/f 1<0.35,
where f1 represents a focal length of the first lens unit and fW represents a focal length of the zoom lens at a wide-angle end.

12. The zoom lens according to claim 1 , wherein the first correction lens system is the entirety of the second lens unit.

13. The zoom lens according to claim 1 , wherein the second correction lens system is constituted by an entirety or a part of the third lens unit.

14. The zoom lens according to claim 1 , wherein the rear lens group includes, in order from the object side to the image side, a fourth lens unit having a negative refractive power and a fifth lens unit having a positive refractive power, and the first to fifth lens units move along loci different from each other during zooming.

15. The zoom lens according to claim 1 , wherein the rear lens group includes a fourth lens unit having a positive refractive power, and the second to fourth lens units move along loci different from each other during zooming.

16. The zoom lens according to claim 15 , wherein the second correction lens system is constituted by an entirety of the third lens unit and an entirety of the fourth lens unit.

17. A zoom lens comprising a plurality of lens units,
wherein spacings between lens units adjacent to each other change during zooming,
wherein the zoom lens has a plurality of correction lens systems that are rotatable about a center of rotation, which is one point on an optical axis or in the vicinity of the optical axis, during image blur correction,
wherein the image blur correction is performed by rotating all the correction lens systems in a first zoom range, and
wherein the image blur correction is performed by rotating only a part of the correction lens systems in a second zoom range different from the first zoom range.

18. An image pickup apparatus comprising:
a zoom lens comprising, in order from an object side to an image side:
a first lens unit having a positive refractive power;
a second lens unit having a negative refractive power;
a third lens unit having a positive refractive power; and
a rear lens group that has one or more lens units,
wherein spacings between lens units adjacent to each other change during zooming,
wherein at least of a part of the second lens unit constitutes a first correction lens system that is rotatable about a first center of rotation, which is one point on an optical axis or in the vicinity of the optical axis, during image blur correction,
wherein at least of a part of an optical system disposed on the image side of the second lens unit constitutes a second correction lens system that is rotatable about a second center of rotation, which is one point on an optical axis or in the vicinity of the optical axis, during image blur correction,
wherein the first center of rotation is positioned on the image side of a surface vertex of a lens surface of the first correction lens system closest to the object side, and
wherein the second center of rotation is positioned on the image side of a surface vertex of a lens surface of the second correction lens system closest to the object side; and
an image pickup element that receives an image which is formed through the zoom lens.

Assignees

• Canon Kk

Inventors

• Aoki Koji

Classifications

• 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

• G02B27/0025 Primary

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

• G02B27/646

  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) · CPC title

• G02B15/1441 Primary

  the first group being positive · CPC title