Zoom lens, an optical apparatus, and a manufacturing method of the zoom lens

Patent metadata

Field	Value
Publication number	US-2016349491-A1
Application number	US-201615161242-A
Country	US
Kind code	A1
Filing date	May 21, 2016
Priority date	Nov 21, 2013
Publication date	Dec 1, 2016
Grant date	—

Abstract

A first lens group (G 1 ) having a positive refractive power, a second lens group (G 2 ) having a negative refractive power, a third lens group (G 3 ) having a positive refractive power, a fourth lens group (G 4 ) having a negative refractive power, and a fifth lens group (G 5 ) having a positive refractive power are arranged in order along an optical axis from an object, and distances between each lens group change when zooming, and the first lens group (G 1 ) is composed of two lenses, and the following expression (1) is satisfied:
0.07< D 1/ fw <0.46
where D1 denotes a thickness on the optical axis of the first lens group (G 1 ), and fw denotes a focal length of the zoom lens (ZL) in a wide-angle end state.

First claim

1 . A zoom lens comprising, in order on an optical axis from an object, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power, distances between each lens group changing upon zooming,
the first lens group being composed of two lenses, and the following conditional expressions being satisfied:
0.07< D 1/ fw< 0.46
where D1 denotes a thickness on the optical axis of the first lens group, and fw denotes a focal length of the zoom lens in a wide-angle end state.

2 . A zoom lens according to claim 1 , wherein all the lens groups move on the optical axis when zooming.

3 . A zoom lens according to claim 1 , wherein a distance on the optical axis from a surface closest to the object in the fifth lens group to an image surface is larger in a telephoto end state than a wide-angle end state.

4 . A zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
0.23<( TL 5- WL 5)/ ft< 1.20 where WL5 denotes a distance on the optical axis from a surface closest to the object in the fifth lens group to an image surface in a wide-angle end state, TL5 denotes a distance on the optical axis from a surface closest to the object in the fifth lens group to an image surface in a telephoto end state, and ft denotes a focal length of the zoom lens in a telephoto end state.

5 . A zoom lens according to claim 1 , composed of, in order from the object, a negative lens, and a positive lens.

6 . A zoom lens according to claim 1 , wherein the first lens group is composed of a cemented lens composed of the two lenses.

7 . A zoom lens according to claim 1 , wherein the second lens group is composed of, in order from the object, a negative lens, a negative lens, and a positive lens.

8 . A zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
0.08<|( W 45β- T 45β)/( ft/fw )|
where W45β denotes composed magnification regarding the fourth lens group and the fifth lens group in a wide-angle end state, T45β denotes composed magnification regarding the fourth lens group and the fifth lens group in a telephoto end state, ft denotes a focal length of the zoom lens in a telephoto end state, and fw denotes a focal length of the zoom lens in a wide-angle end state.

9 . An optical apparatus characterized in equipped with the zoom lens according to claim 1 .

10 . A zoom lens comprising, in order in an optical axis form an object, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power, distances between each lens group changing when zooming, the first lens group being composed of two lenses, and
the following conditional expression being satisfied:
0.08<|( W 45β- T 45β)/( ft/fw )|

where W45β denotes composed magnification regarding the fourth lens group and the fifth lens group in a wide-angle end state, T45β denotes composed magnification of the fourth lens group and the fifth lens group in a telephoto end state, ft denotes a focal length of the zoom lens in a telephoto end state, and fw denotes a focal length of the zoom lens in a wide-angle end state.

11 . An optical apparatus equipped with the zoom lens according to claim 10 .

12 . A manufacturing method of a zoom lens comprising, in order on an optical axis from an object, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power, distances between each lens group changing when zooming,
the first lens group being composed of two lenses, and each lens being disposed in a lens-barrel so that the following conditional expression is satisfied:
0.07< D 1/ fw< 0.46
where D1 denotes a thickness on the optical axis of the first lens group, and fw denotes a focal length of the zoom lens in a wide-angle end state.

13 . A manufacturing method of the zoom lens according to claim 12 , wherein each lens is disposed in the lens-barrel so that a distance on the optical axis from a surface closest to the object in the fifth lens group to an image surface is larger in a telephoto end state than a wide-angle end state.

14 . A manufacturing method of the zoom lens according to claim 12 , wherein each lens is disposed in the lens-barrel so that the following conditional expression is satisfied:
0.23<( TL 5- WL 5)/ ft< 1.20 WL5 denotes a distance on the optical axis from a surface closest to the object in the fifth lens group to an image surface in a wide-angle end state, TL5 denotes a distance on the optical axis from a surface closest to the object in the fifth lens group to an image surface in a telephoto end state, and ft denotes a focal length of the zoom lens in a telephoto end state.

15 . A manufacturing method of the zoom lens according to claim 12 , wherein each lens is disposed in the lens-barrel so that the following conditional expressions is satisfied:
0.08<|( W 45β- T 45β)/( ft/fw )|
W45β denotes composed magnification regarding the fourth lens group and the fifth lens group in a wide-angle end state, T45β denotes composed magnification of the fourth lens group and the fifth lens group in a telephoto end state, ft denotes a focal length of the zoom lens in a telephoto end state, and fw denotes a focal length of the zoom lens in a wide-angle end state.

16 . A manufacturing method of a zoom lens comprising, in order on an optical axis from an object, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power, distances between each lens group changing when zooming,
the first lens group being composed of two lenses, and each lens being disposed in a lens-barrel so that the following conditional expression is satisfied:
0.08<|( W 45β- T 45β)/( ft/fw )|

where W45β denotes composed magnification regarding the fourth lens group and the fifth lens group in a wide-angle end state, T45β denotes composed magnification regarding the fourth lens group and the fifth lens group in a telephoto end state, ft denotes a focal length of the zoom lens in a telephoto end state, and fw denotes a focal length of the zoom lens in a wide-angle end state.

Assignees

• Nikon Corp

Inventors

• Suzuki Atsushi

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

• G02B15/173

  arranged +-+ · CPC title

• G02B5/005

  Diaphragms (for cameras G03B9/02) · CPC title

• G02B15/177 Primary

  having a negative front lens or group of lenses · CPC title

• G02B15/145121 Primary

  arranged +-+-+ · CPC title