Zoom lens and image pickup apparatus including the same

Patent metadata

Field	Value
Publication number	US-2016154226-A1
Application number	US-201514945929-A
Country	US
Kind code	A1
Filing date	Nov 19, 2015
Priority date	Nov 28, 2014
Publication date	Jun 2, 2016
Grant date	—

Abstract

Provided is a zoom lens, including, in order from an object side to an image side: first to fourth lens units respectively having positive, negative, positive and negative refractive powers; and a fifth lens unit having a positive or negative refractive power. In the zoom lens, intervals between adjacent lens units are changed during zooming. The third lens unit includes four or more lenses, and in the third lens unit, a lens arranged closest to the image side, a lens arranged second when counted from the image side, and a lens arranged third when counted from the image side are arranged with air gaps therebetween. A focal length of the zoom lens at a telephoto end, and a movement amount of the first lens unit during zooming from a wide-angle end to the telephoto end are set appropriately.

First claim

What is 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; a fourth lens unit having a negative refractive power; and a fifth lens unit having a positive or negative refractive power, wherein intervals between adjacent lens units are changed during zooming, wherein the third lens unit includes four or more lenses, and in the third lens unit, a lens arranged closest to the image side, a lens arranged second when counted from the image side, and a lens arranged third when counted from the image side are arranged with air gaps therebetween, and wherein the following conditional expression is satisfied:
−0.8< M 1/ ft<− 0.4

where ft represents a focal length of the zoom lens at a telephoto end, and M 1 represents a movement amount of the first lens unit during zooming from a wide-angle end to the telephoto end, provided that a sign of the movement amount is negative when the first lens unit is located on the object side at the telephoto end with respect to the wide-angle end, and is positive when the first lens unit is located on the image side at the telephoto end with respect to the wide-angle end.

2 . A zoom lens according to claim 1 , wherein the fourth lens unit is configured to move during focusing.

3 . A zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
−0.08<( Ro 31− Ri 32)/( Ro 31+ Ri 32)<0.05

where Ro 31 represents curvature radius of a lens surface on the object side of the lens arranged closest to the image side in the third lens unit, and Ri 32 represents curvature radius of a lens surface on the image side of the lens arranged second when counted from the image side in the third lens unit.

4 . A zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
−1.9< f 3/ f 2<−1.2

where f 2 represents a focal length of the second lens unit, and f 3 represents a focal length of the third lens unit.

5 . A zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
1.5< f 3/ fw< 2.3
where f 3 represents a focal length of the third lens unit, and fw represents a focal length of the zoom lens at the wide-angle end.

6 . A zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
−1.5< f 2/ fw<− 0.9

where f 2 represents a focal length of the second lens unit, and fw represents a focal length of the zoom lens at the wide-angle end.

7 . A zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
−15.00< f 4/ fw<− 2.50

where f 4 represents a focal length of the fourth lens unit, and fw represents a focal length of the zoom lens at the wide-angle end.

8 . A zoom lens according to claim 1 , wherein each of the fourth lens unit and the fifth lens unit consists of two or less lenses.

9 . A zoom lens according to claim 1 , wherein the first lens unit consists of four or less lenses.

10 . A zoom lens according to claim 1 , wherein during image stabilization, the lens arranged closest to the image side and the lens arranged second when counted from the image side in the third lens unit are configured to move in a direction having a component in a direction perpendicular to an optical axis.

11 . 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;
a fourth lens unit having a negative refractive power; and
a fifth lens unit having a positive or negative refractive power,
wherein intervals between adjacent lens units are changed during zooming,
wherein the third lens unit includes four or more lenses, and in the third lens unit, a lens arranged closest to the image side, a lens arranged second when counted from the image side, and a lens arranged third when counted from the image side are arranged with air gaps therebetween, and
wherein the following conditional expression is satisfied:
−0.8< M 1/ ft<− 0.4

where ft represents a focal length of the zoom lens at a telephoto end, and M 1 represents a movement amount of the first lens unit during zooming from a wide-angle end to the telephoto end, provided that a sign of the movement amount is negative when the first lens unit is located on the object side at the telephoto end with respect to the wide-angle end, and is positive when the first lens unit is located on the image side at the telephoto end with respect to the wide-angle end; and
an image pickup element configured to receive light of an image formed by the zoom lens.

12 . 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; a fourth lens unit having a negative refractive power; and a fifth lens unit having a positive or negative refractive power, wherein intervals between adjacent lens units are changed during zooming, wherein the second lens unit consists of four or less lenses, the third lens unit consists of four or more lenses, and of a lens arranged closest to the image side and a lens arranged second when counted from the image side in the third lens unit, one is a positive lens, and the other is a negative lens, and wherein the following conditional expressions are satisfied:
−1.9< f 3/ f 2<−1.2

−0.8< M 1/ ft<− 0.4

where f 2 represents a focal length of the second lens unit, f 3 represents a focal length of the third lens unit, ft represents a focal length of the zoom lens at a telephoto end, and M 1 represents a movement amount of the first lens unit during zooming from the wide-angle end to the telephoto end, provided that a sign of the movement amount is negative when the first lens unit is located on the object side at the telephoto end with respect to the wide-angle end, and is positive when the first lens unit is located on the image side at the telephoto end with respect to the wide-angle end.

13 . A zoom lens according to claim 12 , wherein the fifth lens unit has the positive refractive power, and the second lens unit consists of three or four lenses.

14 . A zoom lens according to claim 12 , wherein the lens arranged second and the lens arranged third when counted from the image side in the third lens unit are arranged with an air gap therebetween.

15 . A zoom lens according to claim 12 , wherein the following conditional expression is satisfied:
5< f 3/ fw< 2.3
where fw represents a focal length of the zoom lens at the wide-angle end.

16 . A zoom lens according to claim 12 , wherein the following conditional expression is satisfied:
−1.5< f 2/ fw<− 0.9

where fw represents a focal length of the zoom lens at the wide-angle end.

17 . A zoom lens according to claim 12 , wherein the following conditional expression is satisfied:
−15.00< f 4/ fw<− 2.50

where f 4 represents a focal length of the fourth lens unit, and fw represents a focal length of the zoom lens at the wide-angle end.

18 . A zoom lens according to claim 12 , wherein each of the fourth lens unit and th

Assignees

• Canon Kk

Inventors

• Miyazawa Nobuyuki

Classifications

• 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

• G02B15/20 Primary

  having an additional movable lens or lens group for varying the objective focal length · CPC title

• G02B27/0025

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

• G02B15/145121

  arranged +-+-+ · CPC title

• G02B15/173 Primary

  arranged +-+ · CPC title