阅读说明：本技术 变焦镜头以及光学设备 (Zoom lens and optical apparatus ) 是由 真杉三郎 于 2016-12-09 设计创作，主要内容包括：本发明提供一种变焦镜头以及光学设备。变焦镜头具备沿着光轴从物体侧依次排列的具有正的光焦度的第1透镜组、具有负的光焦度的第2透镜组、具有正的光焦度的第3透镜组、具有负的光焦度的第4透镜组以及具有正的光焦度的第5透镜组,在从广角端状态向远焦端状态进行变倍时,相邻的各透镜组之间的间隔变化,且满足下述的条件式：2.90<|MV5/MV2|<11.50 28.0<ωw<65.0其中,MV5：从广角端状态变倍至远焦端状态时的、所述第5透镜组的以像面为基准的移动量,MV2：从广角端状态变倍至远焦端状态时的、所述第2透镜组的以像面为基准的移动量,ωw：广角端状态下的变焦镜头整体的半视场角(单位：度)。(The invention provides a zoom lens and an optical apparatus. The zoom lens includes a 1 st lens group having positive refractive power, a2 nd lens group having negative refractive power, a 3 rd lens group having positive refractive power, a 4 th lens group having negative refractive power, and a 5 th lens group having positive refractive power, which are arranged in this order from the object side along the optical axis, and when zooming from the wide-angle end state to the telephoto end state, the interval between the adjacent lens groups changes, and the following conditional expression is satisfied: 2.90< | MV5/MV2| < 11.5028.0 < ω w <65.0 wherein MV 5: moving amount of the 5 th lens group with respect to the image plane when varying magnification from the wide-angle end state to the telephoto end state, MV 2: movement amount of the 2 nd lens group with respect to an image plane when zooming from a wide-angle end state to a telephoto end state, ω w: the half field angle (unit: degree) of the entire zoom lens in the wide-angle end state.)

1. A zoom lens, characterized in that,

comprises a 1 st lens group having positive refractive power, a2 nd lens group having negative refractive power, a 3 rd lens group having positive refractive power, a 4 th lens group having negative refractive power, and a 5 th lens group having positive refractive power, which are arranged in this order from the object side along the optical axis,

when zooming from a wide-angle end state to a telephoto end state, the interval between adjacent lens groups varies,

and satisfies the following conditional expressions:

2.90<|MV5/MV2|<11.50

28.0<ωw<65.0

wherein, MV 5: a moving amount of the 5 th lens group with respect to an image plane when zooming from a wide-angle end state to a telephoto end state

MV 2: a moving amount of the 2 nd lens group with respect to an image plane when zooming from a wide-angle end state to a telephoto end state

ω w: the half field angle (unit: degree) of the entire zoom lens in the wide-angle end state.

2. The zoom lens according to claim 1,

the following conditional expressions are satisfied:

5.0<ωt<25.0

wherein, ω t: the half angle of view (unit: degree) of the entire zoom lens in the telephoto end state.

3. The zoom lens according to claim 1,

the following conditional expressions are satisfied:

1.20<β2t/β2w<2.50

wherein, β 2 t: magnification of the 2 nd lens group in the telephoto end state

β 2 w: magnification in a wide-angle end state of the 2 nd lens group.

4. The zoom lens according to claim 1,

the following conditional expressions are satisfied:

1.50<TLt/ft<5.00

wherein, TLt: full length of zoom lens in telephoto end state

ft: the focal length of the entire zoom lens in the state of the far focus end.

5. The zoom lens according to claim 1,

the zoom lens has an aperture stop between the 2 nd lens group and the 3 rd lens group.

6. The zoom lens according to claim 1,

the most object-side lens of the 1 st lens group is a cemented lens of a negative lens and a positive lens.

7. The zoom lens according to claim 1,

the most object-side lens of the 1 st lens group is a cemented lens of a negative meniscus lens and a positive lens.

8. The zoom lens according to claim 1,

and the most object side lens of the 2 nd lens group is a negative lens.

9. The zoom lens according to claim 1,

and the lens most close to the object side in the 4 th lens group is a negative lens.

10. The zoom lens according to claim 1,

the 1 st lens group, the 2 nd lens group, the 3 rd lens group, and the 4 th lens group move to the object side at the time of varying magnification from a wide-angle end to a telephoto end.

11. An optical device provided with the zoom lens according to claim 1.

12. A zoom lens, characterized in that,

comprises a 1 st lens group having positive refractive power, a2 nd lens group having negative refractive power, a 3 rd lens group having positive refractive power, a 4 th lens group having negative refractive power, and a 5 th lens group having positive refractive power, which are arranged in this order from the object side along the optical axis,

when zooming from a wide-angle end state to a telephoto end state, the interval between adjacent lens groups varies,

and satisfies the following conditional expressions:

2.90<|MV5/MV2|<11.50

1.20<β2t/β2w<2.50

wherein, MV 5: a moving amount of the 5 th lens group with respect to an image plane when zooming from a wide-angle end state to a telephoto end state

MV 2: a moving amount of the 2 nd lens group with respect to an image plane when zooming from a wide-angle end state to a telephoto end state

β 2 t: magnification of the 2 nd lens group in the telephoto end state

β 2 w: magnification in a wide-angle end state of the 2 nd lens group.

13. The zoom lens according to claim 12,

the following conditional expressions are satisfied:

1.50<TLt/ft<5.00

wherein, TLt: full length of zoom lens in telephoto end state

ft: the focal length of the entire zoom lens in the state of the far focus end.

14. The zoom lens according to claim 12,

the following conditional expressions are satisfied:

28.0<ωw<65.0

wherein, ω w: the half field angle (unit: degree) of the entire zoom lens in the wide-angle end state.

15. The zoom lens according to claim 12,

the following conditional expressions are satisfied:

5.0<ωt<25.0

wherein, ω t: the half angle of view (unit: degree) of the entire zoom lens in the telephoto end state.

16. The zoom lens according to claim 12,

the zoom lens has an aperture stop between the 2 nd lens group and the 3 rd lens group.

17. The zoom lens according to claim 12,

the most object-side lens of the 1 st lens group is a cemented lens of a negative lens and a positive lens.

18. The zoom lens according to claim 12,

the most object-side lens of the 1 st lens group is a cemented lens of a negative meniscus lens and a positive lens.

19. The zoom lens according to claim 12,

and the most object side lens of the 2 nd lens group is a negative lens.

20. The zoom lens according to claim 12,

and the lens most close to the object side in the 4 th lens group is a negative lens.

21. The zoom lens according to claim 12,

the 1 st lens group, the 2 nd lens group, the 3 rd lens group, and the 4 th lens group move to the object side at the time of varying magnification from a wide-angle end to a telephoto end.

22. An optical device provided with the zoom lens according to claim 12.

Technical Field

The present invention relates to a zoom lens, an optical apparatus using the zoom lens, and a method of manufacturing the zoom lens.

Background

Conventionally, as a wide-angle zoom lens having a zoom ratio of about 4 times, there is disclosed a zoom lens including: the zoom lens includes, in order from the object side along the optical axis, a 1 st lens group having positive power, a2 nd lens group having negative power, a 3 rd lens group having positive power, and a 4 th lens group having negative power, and each lens group is moved to perform magnification change (see, for example, patent document 1). The zoom lens disclosed in patent document 1 realizes a zoom ratio of about 4 times and an aperture ratio of about 2.8 to 6 in F-number by allowing the 1 st to 4 th lens groups to move during zooming, but is required to have a larger aperture and a higher zoom ratio. In particular, a zoom lens having a high zoom ratio suitable for a video camera using a solid-state imaging device or the like, an electronic still camera, or the like is required.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2014-247758

Disclosure of Invention

The zoom lens of the present invention includes a 1 st lens group having positive refractive power, a2 nd lens group having negative refractive power, a 3 rd lens group having positive refractive power, a 4 th lens group having negative refractive power, and a 5 th lens group having positive refractive power, which are arranged in this order from an object side along an optical axis, and when magnification is changed from a wide-angle end state to a telephoto end state, intervals between adjacent lens groups change, and the following conditional expressions are satisfied:

2.90<|MV5/MV2|<11.50

wherein, MV 5: a moving amount of the 5 th lens group with respect to an image plane when zooming from a wide-angle end state to a telephoto end state

MV 2: a moving amount of the 2 nd lens group with respect to an image plane when zooming from a wide-angle end state to a telephoto end state.

The optical apparatus according to the present invention is configured to be mounted with the zoom lens.

The manufacturing method of the present invention is a manufacturing method of a lens barrel, in which a 1 st lens group having positive power, a2 nd lens group having negative power, a 3 rd lens group having positive power, a 4 th lens group having negative power, and a 5 th lens group having positive power are arranged in order from an object side along an optical axis in the barrel, and the manufacturing method is configured such that, when zooming is performed from a wide-angle end state to a telephoto end state, an interval between adjacent lens groups changes, and the following conditional expressions are satisfied:

2.90<|MV5/MV2|<11.50

wherein, MV 5: a moving amount of the 5 th lens group with respect to an image plane when zooming from a wide-angle end state to a telephoto end state

MV 2: a moving amount of the 2 nd lens group with respect to an image plane when zooming from a wide-angle end state to a telephoto end state.

Drawings

Fig. 1 is a sectional view showing a lens structure of a zoom lens according to example 1 of this embodiment.

Fig. 2(a), 2(b) and 2(c) are aberration diagrams in the wide-angle end state, intermediate focal length state and telephoto end state, respectively, of the zoom lens according to embodiment 1.

Fig. 3 is a sectional view showing a lens structure of a zoom lens according to example 2 of this embodiment.

Fig. 4(a), 4(b) and 4(c) are aberration diagrams in the wide-angle end state, intermediate focal length state and telephoto end state, respectively, of the zoom lens of embodiment 2.

Fig. 5 is a sectional view showing a lens structure of a zoom lens according to example 3 of this embodiment.

Fig. 6(a), 6(b) and 6(c) are aberration diagrams in the wide-angle end state, intermediate focal length state and telephoto end state, respectively, of the zoom lens of embodiment 3.

Fig. 7 is a sectional view showing a lens structure of a zoom lens according to example 4 of this embodiment.

Fig. 8(a), 8(b) and 8(c) are aberration diagrams in the wide-angle end state, intermediate focal length state and telephoto end state, respectively, of the zoom lens of embodiment 4.

Fig. 9 is a schematic diagram showing a configuration of a camera including the zoom lens of the present embodiment.

Fig. 10 is a flowchart schematically illustrating a method of manufacturing the zoom lens according to the present embodiment.

Detailed Description

Hereinafter, a zoom lens and an optical apparatus according to embodiments 1 and 2 of the present application will be described with reference to the drawings. As shown in fig. 1, a zoom lens ZL (1), which is an example of a zoom lens ZL according to embodiment 1 of the present application, is configured to include a 1 st lens group G1 having positive optical power, a2 nd lens group G2 having negative optical power, a 3 rd lens group G3 having positive optical power, a 4 th lens group G4 having negative optical power, and a 5 th lens group G5 having positive optical power, which are arranged in this order from the object side along the optical axis. In the zoom lens ZL according to embodiment 1 of the present application, when magnification is changed from the wide-angle end state to the telephoto end state, the adjacent lens groups (i.e., the 1 st to 5 th lens groups G1 to G5) move in the optical axis direction as indicated by arrows in fig. 1. In addition to the above configuration, the zoom lens ZL according to embodiment 1 of the present application satisfies the following conditional expression (1).

2.90<|MV5/MV2|<11.50…(1)

Wherein, MV 5: a moving amount of the 5 th lens group with respect to an image plane when zooming from a wide-angle end state to a telephoto end state

MV 2: a moving amount of the 2 nd lens group with respect to an image plane when zooming from a wide-angle end state to a telephoto end state

The zoom lens ZL according to embodiment 1 of the present application may be the zoom lens ZL (2) shown in fig. 3, the zoom lens ZL (3) shown in fig. 5, or the zoom lens ZL (4) shown in fig. 7.

By configuring the zoom lens ZL according to embodiment 1 of the present application as described above, it is possible to achieve a wider angle and a higher magnification while maintaining the size, coma aberration, and astigmatism of the entire lens. According to embodiment 1 of the present application, a zoom lens suitable for a video camera, an electronic still camera, or the like using a solid-state imaging element or the like can be obtained.

The conditional expression (1) defines an appropriate range of the ratio of the moving amounts of the 2 nd lens group and the 5 th lens group in zooming from the wide-angle end to the telephoto end. When the amount of light is less than the above conditional expression, coma aberration and astigmatism are not preferably deteriorated.

In order to reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (1) is 3.10. In order to more reliably obtain the effect of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (1) is 3.30. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (1) is 3.50. In order to reliably obtain the effects of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (1) is set to 11.00. In order to more reliably obtain the effect of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (1) is 10.50. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (1) is 10.00.

The zoom lens ZL according to embodiment 1 of the present application preferably satisfies the following conditional expression (3).

6.00<|MV4/MV2|<15.00…(3)

Wherein, MV 4: a moving amount of the 4 th lens group with respect to an image plane when zooming from a wide-angle end state to a telephoto end state

Conditional expression (3) specifies an appropriate range of the ratio of the moving amounts of the 2 nd lens group and the 4 th lens group when performing magnification variation from the wide-angle end to the telephoto end. When the amount of light is less than the above conditional expression, coma aberration and astigmatism are not preferably deteriorated.

In order to reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit value of conditional expression (3) is 7.00. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit value of conditional expression (3) is 8.00. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (3) is 9.00. In order to reliably obtain the effects of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (3) is 14.50. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (3) is 14.00. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (3) is 13.40.

With regard to the zoom lens ZL according to embodiment 1 of the present application, it is preferable that the 5 th lens group G5 be moved toward the image (I) side along the optical axis when zooming from the wide-angle end state to the telephoto end state. This can increase the magnification and reduce various aberrations such as astigmatism.

The zoom lens ZL according to embodiment 1 of the present application preferably satisfies the following conditional expression (2).

1.20<β2t/β2w<2.50…(2)

Wherein, β 2 t: magnification of the 2 nd lens group in the telephoto end state

β 2 w: magnification of the 2 nd lens group in a wide-angle end state

Conditional expression (2) specifies an appropriate range of the ratio of magnifications at the wide-angle end and the telephoto end of the 2 nd lens group. When the amount of light is less than the above conditional expression, coma aberration and astigmatism are not preferably deteriorated.

In order to reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (2) is 1.25. In order to more reliably obtain the effect of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (2) is 1.30. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (2) is 1.35. In order to reliably obtain the effects of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (2) is 2.10. In order to more reliably obtain the effect of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (2) is 2.30. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the upper limit of conditional expression (2) is 1.90.

The zoom lens ZL according to embodiment 1 of the present application preferably satisfies the following conditional expression (4).

0.10<(β2t×β4w)/(β2w×β4t)<2.40…(4)

Wherein, beta 4 t: magnification of the 4 th lens group in the telephoto end state

β 4 w: magnification of the 4 th lens group in a wide-angle end state

Conditional expression (4) specifies an appropriate range of the magnification change ratio between the 2 nd lens group and the 4 th lens group when zooming from the wide-angle end to the telephoto end. When the amount of light is less than the above conditional expression, coma aberration and astigmatism are not preferably deteriorated.

In order to reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit value of conditional expression (4) is 0.40. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit value of conditional expression (4) is 0.70. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (4) is 1.00. In order to reliably obtain the effect of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (4) is 2.20. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (4) is 2.00. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (4) is 1.80.

The zoom lens ZL according to embodiment 1 of the present application preferably satisfies the following conditional expression (5).

1.50<TLt/ft<5.00…(5)

Wherein, TLt: full length of zoom lens in telephoto end state

ft: focal length of zoom lens in the state of far focus end

The conditional expression (5) specifies an appropriate range of the ratio of the total length at the far-focus end to the focal length. When the amount of light is less than the conditional expression, spherical aberration, coma aberration, and astigmatism are not preferably deteriorated.

In order to reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (5) is 1.70. In order to more reliably obtain the effect of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (5) is 1.90. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (5) is 2.10. In order to reliably obtain the effect of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (5) is 4.60. In order to more reliably obtain the effect of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (5) is 4.20. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the upper limit of conditional expression (5) is 3.70.

The zoom lens according to embodiment 1 of the present application preferably satisfies conditional expression (6) below.

28.0<ωw<65.0…(6)

Wherein, ω w: half field angle (unit: degree) of zoom lens in whole at wide-angle end state

The conditional expression (6) is a conditional expression for defining an optimum value of the half angle of view at the wide-angle end. Satisfying this conditional expression makes it possible to satisfactorily correct aberrations such as coma, field curvature, and distortion while having a wide half field angle.

In order to reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (6) is 30.0. In order to more reliably obtain the effect of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (6) is 32.0. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (6) is 35.0. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (6) is 38.0. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (6) is 40.0. In order to reliably obtain the effect of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (6) is 60.0. In order to more reliably obtain the effect of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (6) is 55.0. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (6) is 50.0. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (6) is 46.0.

The zoom lens according to embodiment 1 of the present application preferably satisfies the following conditional expression (7).

5.0<ωt<25.0…(7)

Wherein, ω t: half field angle (unit: degree) of zoom lens as a whole in the state of far focus end

The conditional expression (7) is a conditional expression that defines an optimum value of the half angle of view at the telephoto end. By satisfying this conditional expression, it is possible to correct aberrations such as coma, field curvature, and distortion satisfactorily.

In order to reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (7) is 7.0. In order to more reliably obtain the effect of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (7) is 9.0. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (7) is 10.0. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the lower limit of conditional expression (7) is 12.0.

In order to reliably obtain the effect of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (7) is 23.0. In order to more reliably obtain the effect of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (7) is 21.0. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (7) is 19.0. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (7) is set to 17.0. In order to more reliably obtain the effects of embodiment 1 of the present application, it is preferable that the upper limit value of conditional expression (7) is 16.0.

In the zoom lens ZL according to embodiment 1 of the present application, at least a part of the 4 th lens group is preferably a focus lens. This can reduce variations in spherical aberration, coma aberration, and other aberrations during focusing. When focusing from infinity to a close-distance object, at least a part of the 4 th lens group constituting the focus lens is moved to the image side in the optical axis direction.

In the zoom lens ZL according to embodiment 1 of the present application, at least a part of the 3 rd lens group preferably constitutes an anti-shake lens group having a displacement component in a direction perpendicular to the optical axis. This can reduce variation in aberrations such as coma aberration during hand shake correction.

The optical apparatus according to embodiment 1 of the present application is configured to include the zoom lens ZL according to embodiment 1 of the present application. As a specific example thereof, a camera (optical apparatus) including the zoom lens ZL will be described with reference to fig. 9. As shown in fig. 9, the camera 1 is a digital camera including the zoom lens ZL according to embodiment 1 of the present application as a photographing lens 2. In the camera 1, light from an object (object) not shown is condensed by the photographing lens 2 and reaches the image pickup device 3. Thus, light from the subject is captured by the image pickup device 3 and recorded in a memory, not shown, as a subject image. This enables the photographer to take a picture of the subject by the camera 1. In addition, the camera may be a mirror-less camera or a single-lens reflex type camera having a quick return mirror.

With the above configuration, the camera 1 equipped with the zoom lens ZL according to embodiment 1 of the present application as the photographing lens 2 is suitable for a video camera, an electronic still camera, and the like using a solid-state imaging device and the like, and can obtain wide-angle and high-magnification performance while suppressing the size of the entire lens and maintaining astigmatism and chromatic aberration.

Next, referring to fig. 10, a method for manufacturing the zoom lens ZL according to embodiment 1 of the present application will be described. First, the 1 ST lens group G1 having positive power, the 2 nd lens group G2 having negative power, the 3 rd lens group G3 having positive power, the 4 th lens group G4 having negative power, and the 5 th lens group G5 having positive power are arranged in order from the object side along the optical axis in the lens barrel (step ST 1). Next, when zooming is performed from the wide-angle end state to the telephoto end state, the interval between the adjacent lens groups G1 to G5 is changed (step ST 2). Then, the above-described conditional expression (1), which is a predetermined conditional expression, is satisfied (step ST 3).

According to the manufacturing method of embodiment 1 of the present application, a zoom lens can be manufactured as follows: can correct various aberrations well, and has wide-angle large aperture and excellent optical performance.

Next, embodiment 2 of the present application will be described. As shown in fig. 1, a zoom lens ZL (1), which is an example of a zoom lens ZL according to embodiment 2 of the present application, is configured to include a 1 st lens group G1 having positive optical power, a2 nd lens group G2 having negative optical power, a 3 rd lens group G3 having positive optical power, a 4 th lens group G4 having negative optical power, and a 5 th lens group G5 having positive optical power, which are arranged in this order from the object side along the optical axis. In the zoom lens ZL of the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the adjacent lens groups (i.e., the 1 st to 5 th lens groups G1 to G5) move in the optical axis direction as indicated by arrows in fig. 1. In addition to the above configuration, the zoom lens ZL according to embodiment 2 of the present application satisfies the following conditional expression (3).

6.00<|MV4/MV2|<15.00…(3)

Wherein, MV 4: a moving amount of the 4 th lens group with respect to an image plane when zooming from a wide-angle end state to a telephoto end state

MV 2: a moving amount of the 2 nd lens group with respect to an image plane when zooming from a wide-angle end state to a telephoto end state

Conditional expression (3) specifies an appropriate range of the ratio of the moving amounts of the 2 nd lens group and the 4 th lens group when performing magnification variation from the wide-angle end to the telephoto end. When the amount of light is less than the above conditional expression, coma aberration and astigmatism are not preferably deteriorated.

In order to reliably obtain the effect of embodiment 2 of the present application, it is preferable that the lower limit value of conditional expression (3) is 7.00. In order to more reliably obtain the effect of embodiment 2 of the present application, it is preferable that the lower limit value of conditional expression (3) is 8.00. In order to more reliably obtain the effects of embodiment 2 of the present application, it is preferable that the lower limit of conditional expression (3) is 9.00. In order to reliably obtain the effect of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (3) is 14.50. In order to more reliably obtain the effect of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (3) is 14.00. In order to more reliably obtain the effects of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (3) is 13.40.

With regard to the zoom lens ZL according to embodiment 2 of the present application, it is preferable that the 5 th lens group G5 be moved toward the image (I) side along the optical axis when varying magnification from the wide-angle end state to the telephoto end state. This can increase the magnification and reduce various aberrations such as astigmatism.

The zoom lens ZL according to embodiment 2 of the present application preferably satisfies the following conditional expression (2).

1.20<β2t/β2w<2.50…(2)

Wherein, β 2 t: magnification of the 2 nd lens group in the telephoto end state

β 2 w: magnification of the 2 nd lens group in a wide-angle end state

Conditional expression (2) specifies an appropriate range of the ratio of magnifications at the wide-angle end and the telephoto end of the 2 nd lens group. When the amount of light is less than the above conditional expression, coma aberration and astigmatism are not preferably deteriorated.

In order to reliably obtain the effect of embodiment 2 of the present application, it is preferable that the lower limit of conditional expression (2) is 1.25. In order to more reliably obtain the effect of embodiment 2 of the present application, it is preferable that the lower limit of conditional expression (2) is 1.30. In order to more reliably obtain the effects of embodiment 2 of the present application, it is preferable that the lower limit of conditional expression (2) is 1.35. In order to reliably obtain the effect of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (2) is 2.10. In order to more reliably obtain the effect of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (2) is 2.30. In order to more reliably obtain the effects of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (2) is 1.90.

The zoom lens ZL according to embodiment 2 of the present application preferably satisfies the following conditional expression (4).

0.10<(β2t×β4w)/(β2w×β4t)<2.40…(4)

Wherein, beta 4 t: magnification of the 4 th lens group in the telephoto end state

β 4 w: magnification of the 4 th lens group in a wide-angle end state

Conditional expression (4) specifies an appropriate range of the magnification change ratio between the 2 nd lens group and the 4 th lens group when zooming from the wide-angle end to the telephoto end. When the amount of light is less than the above conditional expression, coma aberration and astigmatism are not preferably deteriorated.

In order to reliably obtain the effect of embodiment 2 of the present application, it is preferable that the lower limit value of conditional expression (4) is 0.40. In order to more reliably obtain the effect of embodiment 2 of the present application, it is preferable that the lower limit value of conditional expression (4) is 0.70. In order to more reliably obtain the effects of embodiment 2 of the present application, it is preferable that the lower limit of conditional expression (4) is 1.00. In order to reliably obtain the effect of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (4) is 2.20. In order to more reliably obtain the effect of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (4) is 2.00. In order to more reliably obtain the effects of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (4) is 1.80.

The zoom lens ZL according to embodiment 2 of the present application preferably satisfies the following conditional expression (5).

1.50<TLt/ft<5.00…(5)

Wherein, TLt: full length of zoom lens in telephoto end state

ft: focal length of zoom lens in the state of far focus end

The conditional expression (5) specifies an appropriate range of the ratio of the total length at the far-focus end to the focal length. When the amount of light is less than the conditional expression, spherical aberration, coma aberration, and astigmatism are not preferably deteriorated.

In order to reliably obtain the effect of embodiment 2 of the present application, it is preferable that the lower limit of conditional expression (5) is 1.70. In order to more reliably obtain the effect of embodiment 2 of the present application, it is preferable that the lower limit of conditional expression (5) is 1.90. In order to more reliably obtain the effects of embodiment 2 of the present application, it is preferable that the lower limit of conditional expression (5) is 2.10. In order to reliably obtain the effect of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (5) is 4.60. In order to more reliably obtain the effect of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (5) is 4.20. In order to more reliably obtain the effects of embodiment 2 of the present application, it is preferable that the upper limit of conditional expression (5) is 3.70.

The zoom lens according to embodiment 2 of the present application preferably satisfies conditional expression (6) below.

28.0<ωw<65.0…(6)

Wherein, ω w: half field angle (unit: degree) of zoom lens in whole at wide-angle end state

The conditional expression (6) is a conditional expression for defining an optimum value of the half angle of view at the wide-angle end. Satisfying this conditional expression makes it possible to satisfactorily correct aberrations such as coma, field curvature, and distortion while having a wide half field angle.

In order to reliably obtain the effect of embodiment 2 of the present application, it is preferable that the lower limit of conditional expression (6) is 30.0. In order to more reliably obtain the effect of embodiment 2 of the present application, it is preferable that the lower limit of conditional expression (6) is 32.0. In order to more reliably obtain the effects of embodiment 2 of the present application, it is preferable that the lower limit of conditional expression (6) is 35.0. In order to more reliably obtain the effects of embodiment 2 of the present application, it is preferable that the lower limit of conditional expression (6) is 38.0. In order to more reliably obtain the effects of embodiment 2 of the present application, it is preferable that the lower limit of conditional expression (6) is 40.0. In order to reliably obtain the effect of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (6) is 60.0. In order to more reliably obtain the effect of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (6) is 55.0. In order to more reliably obtain the effect of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (6) is 50.0. In order to more reliably obtain the effect of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (6) is 46.0.

The zoom lens according to embodiment 2 of the present application preferably satisfies the following conditional expression (7).

5.0<ωt<25.0…(7)

Wherein, ω t: half field angle (unit: degree) of zoom lens as a whole in the state of far focus end

The conditional expression (7) is a conditional expression that defines an optimum value of the half angle of view at the telephoto end. By satisfying this conditional expression, it is possible to correct aberrations such as coma, field curvature, and distortion satisfactorily.

In order to reliably obtain the effect of embodiment 2 of the present application, it is preferable that the lower limit of conditional expression (7) is 7.0. In order to more reliably obtain the effect of embodiment 2 of the present application, it is preferable that the lower limit of conditional expression (7) is 9.0. In order to more reliably obtain the effects of embodiment 2 of the present application, it is preferable that the lower limit of conditional expression (7) is 10.0. In order to more reliably obtain the effects of embodiment 2 of the present application, it is preferable that the lower limit of conditional expression (7) is 12.0.

In order to reliably obtain the effect of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (7) is 23.0. In order to more reliably obtain the effect of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (7) is 21.0. In order to more reliably obtain the effect of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (7) is 19.0. In order to more reliably obtain the effect of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (7) is set to 17.0. In order to more reliably obtain the effect of embodiment 2 of the present application, it is preferable that the upper limit value of conditional expression (7) is 16.0.

In the zoom lens ZL according to embodiment 2 of the present application, at least a part of the 4 th lens group is preferably a focus lens. This can reduce variations in spherical aberration, coma aberration, and other aberrations during focusing. Further, the structure is as follows: when focusing is performed from infinity to a close object, at least a part of the 4 th lens group constituting the focusing lens moves to the image side in the optical axis direction.

In the zoom lens ZL according to embodiment 2 of the present application, at least a part of the 3 rd lens group preferably constitutes an anti-shake lens group having a displacement component in a direction perpendicular to the optical axis. This can reduce variation in aberrations such as coma aberration during hand shake correction.

The optical apparatus according to embodiment 2 of the present application is configured to include the zoom lens ZL according to embodiment 2 of the present application. Specifically, the camera (optical device) camera 1 including the zoom lens ZL has the same configuration as the camera shown in fig. 9, and is a digital camera including the zoom lens ZL according to embodiment 2 of the present application as a photographing lens 2. This configuration is the same as the camera including the zoom lens ZL according to embodiment 1 of the present application, and therefore, detailed description thereof is omitted.

With the above configuration, the camera 1 equipped with the zoom lens ZL according to embodiment 2 of the present application as the photographing lens 2 is suitable for a video camera, an electronic still camera, and the like using a solid-state imaging device and the like, and can obtain wide-angle and high-magnification performance while suppressing the size of the entire lens and maintaining astigmatism and chromatic aberration.

Next, a method for manufacturing the zoom lens ZL according to embodiment 2 of the present application described above will be described in detail with reference to fig. 10. Fig. 10 is used for the description of the manufacturing method of embodiment 1 of the present application, but the manufacturing method of embodiment 2 of the present application is also described using this figure. First, the 1 ST lens group G1 having positive power, the 2 nd lens group G2 having negative power, the 3 rd lens group G3 having positive power, the 4 th lens group G4 having negative power, and the 5 th lens group G5 having positive power are arranged in order from the object side along the optical axis in the lens barrel (step ST 1). Next, when zooming is performed from the wide-angle end state to the telephoto end state, the interval between the adjacent lens groups G1 to G5 is changed (step ST 2). Then, the above-described conditional expression (3), which is a predetermined conditional expression, is satisfied (step ST 3).

According to the manufacturing method of embodiment 2 of the present application, a zoom lens can be manufactured as follows: can correct various aberrations well, and has wide-angle large aperture and excellent optical performance.

Examples

Hereinafter, zoom lenses ZL according to examples of embodiments 1 and 2 of the present application will be described with reference to the drawings. Fig. 1, 3, 5, and 7 are sectional views showing the structure of zoom lenses ZL { ZL (1) to ZL (4) } of embodiments 1 to 4, and the like. Arrows shown in the lower part of these drawings indicate the moving directions of the 1 st to 5 th lens groups G1 to G5 and the aperture stop S upon zooming (magnification-varying operation) from the wide-angle end state to the telephoto end state.

In the figure, the 4 th lens group G4 is used as a focus lens, and the movement direction of the focus lens when focusing from infinity to a close object is shown by an arrow together with a symbol such as "∞". In addition, all or at least a part of the 3 rd lens group G3 is used as an anti-shake lens having a displacement component perpendicular to the optical axis.

In these figures, each lens group is represented by a combination of a reference numeral G and a numeral, and each lens is represented by a combination of a reference numeral L and a numeral. In this case, in order to prevent the reference numerals, the kinds of numerals, and the number from becoming complicated, the lens groups and the like are represented individually using combinations of the reference numerals and the numerals in each embodiment. Therefore, even if the same reference numerals and combinations of numerals are used in the embodiments, the same configurations are not meant.

Tables 1 to 4 showing the data of the parameters in examples 1 to 4 are shown below.

In the table of [ lens parameters ], the surface number indicates the order of optical surfaces from the object side along the direction in which the light beam travels, R indicates the radius of curvature of each optical surface (the value at which the surface whose center of curvature is on the image side is positive), D indicates the distance on the optical axis from each optical surface to the next optical surface, that is, the surface distance, nd indicates the refractive index of the material of the optical member with respect to the D-line (wavelength 587.6nm), and vd indicates the abbe number of the material of the optical member with respect to the D-line as a reference. The surface numbers indicate the order of lens surfaces from the object side along the traveling direction of the light ray. The "∞" of the radius of curvature denotes a plane or an opening, and the (aperture S) denotes an aperture stop S. The description of the refractive index nd of air being 1.00000 is omitted. When the lens surface is an aspherical surface, a mark is attached to the surface number and the paraxial radius of curvature is shown in the column of the radius of curvature R.

The table of [ overall parameters ] shows parameters of the entire zoom lens, F denotes a focal length of the entire lens system, fno denotes an F value, and ω denotes a half field angle (maximum incident angle, unit "° (deg)"). BF represents a distance (back focus) from the lens final surface to the image plane I on the optical axis at the time of infinity focusing, TL represents the total lens length, and BF is added to the distance from the lens foremost surface to the lens final surface on the optical axis. These values are shown for the respective variable magnification states of the Wide-angle end state (Wide), the intermediate focal length (Middle), and the telephoto end state (Tele).

In [ aspheric surface data]In the table of (1), regarding [ lens parameters ]]The aspherical surface shown in (a) shows the shape thereof by the following expression (a). X (y) represents a distance (amount of sag) along the optical axis direction from a tangent plane at the vertex of the aspherical surface to a position on the aspherical surface at a height y, R represents a curvature radius (paraxial curvature radius) of the reference spherical surface, κ represents a conic constant, and Ai represents an i-th aspherical coefficient. "E-n" represents ". times.10^-n". For example, 1.234E-05 ═ 1.234 × 10^-5. Note that the second order aspherical surface coefficient a2 is 0, and the description thereof is omitted.

X(y)＝(y²/R)/{1+(1-κ×y²/R²)^1/2}+A4×y⁴+A6×y⁶+A8×y⁸+A10×y¹⁰+A12×y¹²…(a)

The table of [ variable interval data ] shows the surface interval Di to the next surface at the surface number i where the surface interval becomes "variable" in the table representing [ lens parameter ]. For example, in embodiment 1, the face intervals D3, D9, D19, D21, D23 at the face numbers 3, 9, 19, 21, 23 are shown. f denotes a focal length of the entire zoom lens system.

The table of [ lens group data ] indicates the surface number of the group start surface (the surface closest to the object side) in the 1 st to 4 th (or 5 th) lens groups, the focal length of each group, and the lens configuration length.

The table of [ conditional expression corresponding values ] shows values corresponding to the conditional expressions (1) to (7) described above.

Hereinafter, in all the parameter values, the focal length f, the radius of curvature R, the surface distance D, other lengths, and the like described are generally used as "mm" unless otherwise specified, but the same optical performance can be obtained even if the optical system is scaled up or down, and therefore the present invention is not limited thereto.

The above description is of the same matters in all the embodiments, and the repetitive description in each of the following embodiments is omitted.

(embodiment 1)

Embodiment 1 will be described with reference to fig. 1, fig. 2, and table 1. Fig. 1 is a diagram showing a lens structure of a zoom lens ZL (1) of example 1 of this embodiment. The zoom lens ZL (1) includes, in order from the object side along the optical axis, a 1 st lens group G1 having positive refractive power, a2 nd lens group G2 having negative refractive power, a 3 rd lens group G3 having positive refractive power, a 4 th lens group G4 having negative refractive power, and a 5 th lens group G5 having positive refractive power. The reference numeral (+) or (-) attached to each lens group denotes the power of each lens group. The optical filter FL is provided on the image plane I side of the 5 th lens group G5. The filter FL is formed of a low-pass filter, an infrared cut filter, or the like. In addition, an aperture stop S is arranged to be located on the object side of the 3 rd lens group G3. Although this aperture stop S is configured independently of the 3 rd lens group G3, it moves in the optical axis direction together with the 3 rd lens group G3.

In the magnification change, the 1 st to 5 th lens groups G1 to G5 move in the axial direction as indicated by arrows in fig. 1. Therefore, the surface intervals D3, D9, D19, D21, and D23 are variable, and the values are shown in the table of [ variable interval data ].

The 1 st lens group G1 is composed of a cemented lens of a negative meniscus lens L11 with a convex surface (1 st surface) toward the object side and a positive meniscus lens L12 with a convex surface toward the object side, which are arranged in this order from the object side along the optical axis.

The 2 nd lens group G2 is composed of, in order from the object side along the optical axis, a negative meniscus lens L21 with the convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L23 with the convex surface facing the object side. Both side surfaces of the negative meniscus lens L21 are aspherical.

The 3 rd lens group is composed of a biconvex positive lens L31, a negative meniscus lens L32 with the convex surface facing the object side, a cemented lens of a biconcave negative lens L33 and a biconvex positive lens L34, and a biconvex positive lens L35, which are arranged in this order from the object side along the optical axis. Both side surfaces of the positive lens L31 are aspherical.

The 4 th lens group G4 is composed of a negative meniscus lens L41 with the convex surface facing the object side.

The 5 th lens group G5 is composed of a positive meniscus lens L51 with the convex surface facing the object side. The object-side surface of the positive meniscus lens L51 is aspherical.

In the zoom lens ZL (1), focusing from infinity (a distant object) to a close object is performed by moving the 4 th lens group G4 in the image plane direction. Further, the 3 rd lens group G3 is configured to have an anti-shake lens group having a displacement component in a direction perpendicular to the optical axis, and to perform image shake correction (anti-shake, hand shake correction) on the image plane I, in whole or at least a part thereof (the 3 rd lens group G3 may be the whole, or any one or a combination of the lenses L31 to L35 configuring the 3 rd lens group G3).

The values of the parameters of the optical system of example 1 are shown in table 1 below.

(Table 1)

[ lens data ]

[ Overall parameters ]

[ aspherical data ]

[ variable Interval data ]

[ zoom lens group data ]

[ corresponding values of conditional expressions ]

Conditional expression (1) | MV5/MV2| -7.94

Conditional expression (2) β 2t/β 2w ═ 1.70

Conditional expression (3) | MV4/MV2| -12.28

Conditional expression (4) (β 2t × β 4w)/(β 2w × β 4t) is 1.59

Conditional expression (5) TLt/ft 2.46

Conditional expression (6) ω w is 43.5

Conditional expression (7) (. omega.t) 14.4

As shown in the table of [ conditional expression correspondence values ] above, the zoom lens ZL (1) of embodiment 1 shown in fig. 1 satisfies all of the conditional expressions (1) to (7) above.

Fig. 2(a), 2(b), and 2(c) are aberration diagrams at infinity focusing time in the wide angle end state, intermediate focal length state, and far focal end state, respectively, of the zoom lens ZL (1) of embodiment 1. As can be seen from the respective aberration diagrams, the zoom lens ZL (1) of embodiment 1 corrects the respective aberrations well from the wide-angle end state to the telephoto end state and has excellent imaging performance. Further, distortion can be corrected by image processing after imaging, and optical correction is not necessary.

In fig. 2, FNO represents an F value, and ω represents a half field angle (unit is "°") for each image. D represents an aberration in a D-line (λ 587.6nm), and g represents an aberration in a g-line (λ 435.8 nm). In the spherical aberration diagram, astigmatism diagram, and coma diagram, the solid line indicates the aberration at the sagittal image surface, and the broken line indicates the aberration at the meridional image surface. The description is the same for all aberration diagrams of the following embodiments, and the repetitive description below is omitted.

(embodiment 2)

Embodiment 2 will be described with reference to fig. 3, 4 and table 2. Fig. 3 is a diagram showing a lens structure of a zoom lens ZL (2) of example 2 of this embodiment. The zoom lens ZL (2) includes, in order from the object side along the optical axis, a 1 st lens group G1 having positive refractive power, a2 nd lens group G2 having negative refractive power, a 3 rd lens group G3 having positive refractive power, a 4 th lens group G4 having negative refractive power, and a 5 th lens group G5 having positive refractive power. The optical filter FL is provided on the image plane I side of the 5 th lens group G5. In addition, an aperture stop S is arranged to be located on the object side of the 3 rd lens group G3. Although this aperture stop S is configured independently of the 3 rd lens group G3, it moves in the optical axis direction together with the 3 rd lens group G3.

In the magnification change, the 1 st to 5 th lens groups G1 to G5 move in the axial direction as indicated by arrows in fig. 3. Therefore, the surface intervals D3, D9, D19, D21, and D23 are variable, and the values are shown in the table of [ variable interval data ].

The 1 st lens group G1 is composed of a cemented lens of a negative meniscus lens L11 with a convex surface (1 st surface) toward the object side and a positive meniscus lens L12 with a convex surface toward the object side, which are arranged in this order from the object side along the optical axis.

The 2 nd lens group G2 is composed of, in order from the object side along the optical axis, a negative meniscus lens L21 with the convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L23 with the convex surface facing the object side. Both side surfaces of the negative meniscus lens L21 are aspherical.

The 3 rd lens group is composed of a biconvex positive lens L31, a negative meniscus lens L32 with the convex surface facing the object side, a cemented lens of a biconcave negative lens L33 and a biconvex positive lens L34, and a biconvex positive lens L35, which are arranged in this order from the object side along the optical axis. Both side surfaces of the positive lens L31 and both side surfaces of the positive lens L35 are aspherical.

The 4 th lens group G4 is composed of a biconcave negative lens L41.

The 5 th lens group G5 is composed of a positive meniscus lens L51 with the convex surface facing the object side. The object-side surface of the positive meniscus lens L51 is aspherical.

In the zoom lens ZL (2), focusing from infinity (a distant object) to a close object is performed by moving the 4 th lens group G4 in the image plane direction. Further, the 3 rd lens group G3 constitutes an anti-shake lens group having a displacement component in a direction perpendicular to the optical axis, in whole or at least in part, and performs image shake correction (anti-shake, hand shake correction) on the image plane I.

The values of the parameters of the optical system of example 2 are shown in table 2 below.

(Table 2)

[ lens data ]

[ Overall parameters ]

[ aspherical data ]

[ variable Interval data ]

[ zoom lens group data ]

[ corresponding values of conditional expressions ]

Conditional expression (1) | MV5/MV2| -3.78

Conditional expression (2) β 2t/β 2w ═ 1.70

Conditional expression (3) | MV4/MV2| -10.10

Conditional expression (4) (β 2t × β 4w)/(β 2w × β 4t) is 1.51

Conditional expression (5) TLt/ft 2.42

Conditional expression (6) ω w is 42.6

Conditional expression (7) (. omega.t) 14.4

As shown in the table of [ conditional expression correspondence values ] above, the zoom lens ZL (2) of embodiment 2 shown in fig. 3 satisfies all of the conditional expressions (1) to (7) above.

Fig. 4(a), 4(b), and 4(c) are aberration diagrams at infinity focusing time in the wide angle end state, intermediate focal length state, and far focal end state, respectively, of the zoom lens ZL (2) of embodiment 2. As can be seen from the respective aberration diagrams, the zoom lens ZL (2) of embodiment 2 corrects the respective aberrations well from the wide-angle end state to the telephoto end state, and has excellent imaging performance.

(embodiment 3)

Embodiment 3 will be described with reference to fig. 5, 6, and table 3. Fig. 5 is a diagram showing a lens structure of a zoom lens ZL (3) of example 3 of this embodiment. The zoom lens ZL (3) includes, in order from the object side along the optical axis, a 1 st lens group G1 having positive refractive power, a2 nd lens group G2 having negative refractive power, a 3 rd lens group G3 having positive refractive power, a 4 th lens group G4 having negative refractive power, and a 5 th lens group G5 having positive refractive power. The optical filter FL is provided on the image plane I on the image side of the 5 th lens group G5. In addition, an aperture stop S is arranged to be located on the object side of the 3 rd lens group G3. Although this aperture stop S is configured independently of the 3 rd lens group G3, it moves in the optical axis direction together with the 3 rd lens group G3.

In the magnification change, the 1 st to 5 th lens groups G1 to G5 move in the axial direction as indicated by arrows in fig. 5. Therefore, the surface intervals D3, D9, D19, D21, and D23 are variable, and the values are shown in the table of [ variable interval data ].

The 1 st lens group G1 is composed of a cemented lens of a negative meniscus lens L11 with a convex surface (1 st surface) toward the object side and a positive meniscus lens L12 with a convex surface toward the object side, which are arranged in this order from the object side along the optical axis.

The 2 nd lens group G2 is composed of, in order from the object side along the optical axis, a negative meniscus lens L21 with the convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L23 with the convex surface facing the object side. Both side surfaces of the negative meniscus lens L21 are aspherical.

The 3 rd lens group is composed of a biconvex positive lens L31, a negative meniscus lens L32 with the convex surface facing the object side, a cemented lens of a biconcave negative lens L33 and a biconvex positive lens L34, and a biconvex positive lens L35, which are arranged in this order from the object side along the optical axis. Both side surfaces of the positive lens L31 and the positive lens L35 are aspheric.

The 4 th lens group G4 is composed of a biconcave negative lens L41.

The 5 th lens group G5 is composed of a positive meniscus lens L51 with the convex surface facing the object side. The object-side surface of the positive meniscus lens L51 is aspherical.

In the zoom lens ZL (3), focusing from infinity (a distant object) to a close object is performed by moving the 4 th lens group G4 in the image plane direction. Further, the 3 rd lens group G3 constitutes an anti-shake lens group having a displacement component in a direction perpendicular to the optical axis, in whole or at least in part, and performs image shake correction (anti-shake, hand shake correction) on the image plane I.

The values of the parameters of the optical system of example 3 are shown in table 3 below.

(Table 3)

[ lens data ]

[ Overall parameters ]

[ aspherical data ]

[ variable Interval data ]

[ zoom lens group data ]

[ corresponding values of conditional expressions ]

Conditional expression (1) | MV5/MV2| -9.57

Conditional expression (2) β 2t/β 2w is 1.71

Conditional expression (3) | MV4/MV2|, 12.78

Conditional expression (4) (β 2t × β 4w)/(β 2w × β 4t) is 1.64

Conditional expression (5) TLt/ft 2.49

Conditional expression (6) ω w is 42.6

Conditional expression (7) (. omega.t) 14.4

As shown in the table of [ conditional expression correspondence values ] above, the zoom lens ZL (3) of embodiment 3 shown in fig. 5 satisfies all of the conditional expressions (1) to (7) above.

Fig. 6(a), 6(b) and 6(c) are aberration diagrams at infinity focusing time in the wide angle end state, intermediate focal length state and telephoto end state, respectively, of the zoom lens ZL (3) of embodiment 3. As is apparent from the respective aberration diagrams, the zoom lens ZL (3) of embodiment 2 corrects the respective aberrations well from the wide-angle end state to the telephoto end state, and has excellent imaging performance.

(embodiment 4)

Embodiment 4 will be described with reference to fig. 7, 8, and table 4. Fig. 7 is a diagram showing a lens structure of a zoom lens ZL (4) of example 4 of this embodiment. The zoom lens ZL (4) includes, in order from the object side along the optical axis, a 1 st lens group G1 having positive refractive power, a2 nd lens group G2 having negative refractive power, a 3 rd lens group G3 having positive refractive power, a 4 th lens group G4 having negative refractive power, and a 5 th lens group G5 having positive refractive power. The optical filter FL is provided on the image plane I side of the 5 th lens group G5. Further, an aperture stop S is disposed inside the 3 rd lens group G3.

In the magnification change, the 1 st to 5 th lens groups G1 to G5 move in the axial direction as indicated by arrows in fig. 7. Therefore, the surface intervals D3, D9, D19, D21, and D24 are variable, and the values are shown in the table of [ variable interval data ].

The 1 st lens group G1 is composed of a cemented lens of a negative meniscus lens L11 with a convex surface facing the object side and a positive meniscus lens L12 with a convex surface facing the object side, which are arranged in order from the object side along the optical axis.

The 2 nd lens group G2 is composed of a negative meniscus lens L21 having a convex surface facing the object side, a biconcave negative lens L22, and a biconvex positive lens L23, which are arranged in this order from the object side along the optical axis. Both side surfaces of the negative meniscus lens L21 are aspherical.

The 3 rd lens group is composed of a biconvex positive lens L31, a negative meniscus lens L32 with the convex surface facing the object side, a cemented lens of a biconcave negative lens L33 and a biconvex positive lens L34, and a biconvex positive lens L35, which are arranged in this order from the object side along the optical axis. Both side surfaces of the positive lens L31 and the positive lens L35 are aspheric.

The 4 th lens group G4 is composed of a negative meniscus lens L41 with the convex surface facing the object side.

The 5 th lens group G5 is composed of a biconvex positive lens L51 and a negative meniscus lens L52 having a convex surface facing the image side, which are arranged in this order from the object side along the optical axis.

In the zoom lens ZL (4), focusing from infinity (a distant object) to a close object is performed by moving the 4 th lens group G4 in the image plane direction. Further, the 3 rd lens group G3 constitutes an anti-shake lens group having a displacement component in a direction perpendicular to the optical axis, in whole or at least in part, and performs image shake correction (anti-shake, hand shake correction) on the image plane I.

The values of the parameters of the optical system of example 4 are shown in table 4 below.

(Table 4)

[ lens data ]

[ Overall parameters ]

[ aspherical data ]

[ variable Interval data ]

[ zoom lens group data ]

[ corresponding values of conditional expressions ]

Conditional expression (1) | MV5/MV2| -4.04

Conditional expression (2) β 2t/β 2w ═ 1.44

Conditional expression (3) | MV4/MV2| -12.07

Conditional expression (4) (β 2t × β 4w)/(β 2w × β 4t) is 1.25

Conditional expression (5) TLt/ft is 3.32

Conditional expression (6) ω w is 42.8

Conditional expression (7) (. omega.t) 14.5

As shown in the table of [ conditional expression correspondence values ] above, the zoom lens ZL (4) of embodiment 4 shown in fig. 7 satisfies all of the conditional expressions (1) to (7) above.

Fig. 8(a), 8(b) and 8(c) are aberration diagrams at infinity focusing time in the wide angle end state, intermediate focal length state and telephoto end state, respectively, of the zoom lens ZL (4) of embodiment 4. As is apparent from the respective aberration diagrams, the zoom lens ZL (4) of embodiment 2 corrects the respective aberrations well from the wide-angle end state to the telephoto end state, and has excellent imaging performance.

The above embodiments show a specific example of the invention of the present application, and the invention of the present application is not limited thereto.

The following can be appropriately adopted within a range not to impair the optical performance of the zoom lens of the present embodiment.

Although a 5-group configuration is shown as an example of the zoom lens according to the present embodiment, the present application is not limited thereto, and a zoom lens having another group configuration (for example, 6 groups or the like) may be configured. Specifically, the zoom lens according to the present embodiment may be configured to include a lens or a lens group on the most object side or the most image side. In addition, the lens group means a portion having at least one lens separated by an air space that varies when magnification-varying is performed.

A single or a plurality of lens groups or a partial lens group may be used as a focusing lens group that moves in the optical axis direction to focus from an infinity object to a close object. The focusing lens group can be applied to auto focusing, and is also suitable for motor driving (using an ultrasonic motor or the like) for auto focusing.

The lens group or a part of the lens group may be used as an anti-shake lens group that moves so as to have a component in a direction perpendicular to the optical axis or rotationally moves (swings) in an in-plane direction including the optical axis, thereby correcting image shake caused by hand shake.

The lens surface may be formed of a spherical surface or a flat surface, or may be formed of an aspherical surface. When the lens surface is a spherical surface or a flat surface, lens processing and assembly adjustment become easy, and deterioration of optical performance due to errors in processing and assembly adjustment is prevented, which is preferable. Further, even in the case of image plane shift, deterioration in drawing performance is small, and therefore, this is preferable.

When the lens surface is an aspherical surface, the aspherical surface may be any of an aspherical surface formed by polishing, a glass-molded aspherical surface formed by molding glass into an aspherical shape with a mold, and a composite aspherical surface formed by molding resin into an aspherical shape on a surface of glass. The lens surface may be a diffraction surface, or the lens may be a refractive index distribution lens (GRIN lens) or a plastic lens.

The aperture stop is preferably disposed near or in the 3 rd lens group, but a member as the aperture stop may not be provided, and the function thereof may be replaced by a frame of the lens.

On each lens surface, an antireflection film having high transmittance in a wide wavelength region may also be applied in order to reduce glare and ghost and achieve good optical performance with high contrast.

The zoom lens of the present embodiment has a zoom ratio of about 1.5 to 7.5.

Description of the reference symbols

G1 first lens group G2 second lens group G2

G3 lens group 3, G4 lens group 4

G5 lens group 5 FL filter

I image surface S aperture diaphragm