CN109960023B

CN109960023B - Zoom lens and imaging device

Info

Publication number: CN109960023B
Application number: CN201811123285.2A
Authority: CN
Inventors: 濑川敏也; 田口博规
Original assignee: Tamron Co Ltd
Current assignee: Tamron Co Ltd
Priority date: 2017-12-22
Filing date: 2018-09-26
Publication date: 2021-10-29
Anticipated expiration: 2038-09-26
Also published as: CN109960023A; JP2019113700A; JP6840661B2

Abstract

A compact and high-performance zoom lens having a high zoom ratio and capable of maintaining good optical performance over the entire zoom region is disclosed. The zoom lens is configured to have, arranged in order from an object side: 1 st lens group (G) having negative refractive power₁) And a 2 nd lens group (G) having positive refractive power₂) And a 3 rd lens group (G) having negative refractive power₃) And a subsequent lens group (G)_R). The zoom lens keeps the 1 st lens group (G) at all times when zooming from the wide-angle end to the telephoto end₁) At least the 2 nd lens group (G) is fixed relative to the image plane IMG₂) And group 3 lens (G)₃) Moving along the optical axis to change the interval of the lens groups on the optical axis. Also, by satisfying the predetermined condition, a small and high-performance zoom lens having a high zoom ratio and capable of maintaining good optical performance over the entire zoom region is realized.

Description

Zoom lens and imaging device

Technical Field

The present invention relates to a zoom lens and an imaging device, and more particularly to a zoom lens suitable for an imaging device having a solid-state imaging element such as a CCD or a CMOS mounted thereon, and an imaging device having the zoom lens.

Background

Image pickup apparatuses equipped with a CCD such as a single-lens reflex camera, a digital still camera, a video camera, and a monitoring camera, and a solid-state image pickup device such as a cmos have been rapidly spreading. In response to this, a zoom lens applicable to an imaging device having a solid-state imaging element such as a CCD or a CMOS mounted thereon has been proposed (for example, see patent document 1).

The zoom lens disclosed in patent document 1 is an optical system as follows: the zoom lens includes, in order from the object side, a 1 st lens group having negative refractive power, a 2 nd lens group having positive refractive power, a 3 rd lens group having negative refractive power, a 4 th lens group having positive or negative refractive power, and a 5 th lens group having positive refractive power, wherein the 1 st lens group and the 5 th lens group are fixed to an image forming surface, and the 2 nd lens group, the 3 rd lens group, and the 4 th lens group are moved to zoom from the wide angle end to the telephoto end.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 3226297

As a zoom lens for a monitoring camera, a high-magnification large-diameter zoom lens has been desired, but in recent years, due to the progress of high pixel count of a solid-state imaging device, a high-resolution (high-performance) lens having finer features that can be confirmed in an object has been expected more and more. Accordingly, there is a strong demand for a zoom lens that is compact, has a further high zoom level, and is low in cost, in addition to achieving high performance of an optical system.

However, the zoom lens disclosed in patent document 1 has a wide angle, but has a zoom ratio as low as about 4 times, and thus cannot sufficiently satisfy the recent demand.

Disclosure of Invention

In order to solve the above-described problems of the prior art, it is an object of the present invention to provide a compact and high-performance zoom lens having a high zoom ratio and capable of maintaining good optical performance throughout the entire zoom region. Another object of the present invention is to provide an imaging apparatus having a high zoom ratio and a compact and high-performance zoom lens.

In order to solve the above problems and achieve the object, a zoom lens according to the present invention is a zoom lens comprising, in order from an object side, a 1 st lens group having a negative refractive power, a 2 nd lens group having a positive refractive power, a 3 rd lens group having a negative refractive power, and subsequent lens groups, wherein zooming from a wide-angle end to a telephoto end is performed by moving at least the 2 nd lens group and the 3 rd lens group along an optical axis while keeping the 1 st lens group fixed with respect to an image plane, and by changing an interval between the lens groups on the optical axis, and the zoom lens satisfies a conditional expression:

(1)3.5≦|F1/Fw|≦20.0

(2)0.7≦|F1/Ft|≦2.0

(3)1.9≦|F2/F3|≦5.0

wherein F1 denotes a focal distance of the 1 st lens group, Fw denotes a focal distance of the zoom lens at the wide-angle end, Ft denotes a focal distance of the zoom lens at the telephoto end, F2 denotes a focal distance of the 2 nd lens group, and F3 denotes a focal distance of the 3 rd lens group.

According to the present invention, it is possible to provide a small and high-performance zoom lens having a high zoom ratio and capable of maintaining good optical performance over the entire zoom region.

The invention has the following beneficial effects:

according to the present invention, the following effects can be obtained: a compact and high-performance zoom lens having a high zoom ratio and capable of maintaining good optical performance over the entire zoom region can be provided. In addition, the following effects can be achieved: an imaging device having a high zoom ratio, a small-sized zoom lens and high performance can be provided.

Drawings

Fig. 1 shows a cross-sectional view along an optical axis showing a structure of a zoom lens of embodiment 1.

Fig. 2 shows various aberration diagrams of the zoom lens of embodiment 1.

Fig. 3 shows a cross-sectional view along the optical axis showing the structure of a zoom lens of embodiment 2.

Fig. 4 shows various aberration diagrams of the zoom lens of embodiment 2.

Fig. 5 shows a cross-sectional view along the optical axis showing the structure of a zoom lens of embodiment 3.

Fig. 6 shows various aberration diagrams of the zoom lens of embodiment 3.

Fig. 7 shows a cross-sectional view along the optical axis showing the structure of a zoom lens of embodiment 4.

Fig. 8 shows various aberration diagrams of the zoom lens of embodiment 4.

Fig. 9 is a diagram showing an example of an imaging apparatus including the zoom lens of the present invention.

Detailed Description

Hereinafter, preferred embodiments of the zoom lens and the imaging apparatus according to the present invention will be described in detail.

A zoom lens of the present invention is composed of a 1 st lens group having a negative refractive power, a 2 nd lens group having a positive refractive power, a 3 rd lens group having a negative refractive power, and subsequent lens groups, which are arranged in this order from an object side. Also, zooming from the wide-angle end to the telephoto end is performed by: at least the 2 nd lens group and the 3 rd lens group are moved along the optical axis while keeping the 1 st lens group fixed with respect to the image surface at all times, thereby changing the intervals of the respective lens groups on the optical axis.

In the zoom lens of the present invention, the 2 nd lens group and the 3 rd lens group perform a zooming action. By moving the 2 nd lens group and the 3 rd lens group together at the time of zooming, it is possible to favorably correct a focus movement and aberration variation generated at the time of zooming, and it is possible to realize a zoom optical system having high resolution. In addition, by fixing the 1 st lens group during zooming, the total length of the optical system can be kept short, and a compact optical system can be realized. Further, since the 1 st lens group tends to be a heavy lens group due to its large outer diameter, it is possible to simplify the driving mechanism of the optical system by fixing it at the time of zooming. By so doing, aberration correction in the entire zoom region becomes easy, and a small zoom lens having good optical performance can be realized.

In the zoom lens of the present invention, in view of the high pixel count of the solid-state image sensor, various conditions are set as follows in order to realize a lens having a high resolution with more subtle features that allow the subject to be confirmed.

First, in the zoom lens of the present invention, it is preferable that the following conditional expression is satisfied, where F1 is a focal length of the 1 st lens group and Fw is a focal length of the zoom lens at the wide-angle end.

(1)3.5≦|F1/Fw|≦20.0

Conditional expression (1) is an expression that specifies a ratio between a focal length of the 1 st lens group and a focal length of the zoom lens at the wide-angle end. By satisfying the conditional expression (1), a high zoom ratio can be achieved at the wide-angle end, and good optical performance can be maintained.

If the refractive power of the 1 st lens group is less than the lower limit of the conditional expression (1), the refractive power becomes too strong, and it becomes difficult to correct curvature of field and astigmatism, and therefore, good optical performance cannot be maintained. On the other hand, in conditional expression (1), when it is larger than the upper limit thereof, the refractive power of the 1 st lens group becomes too weak, and in order to achieve a high zoom ratio, the moving amounts of the 2 nd lens group and the 3 rd lens group at the time of zooming are increased, and the total length of the optical system is extended, so that it is difficult to achieve downsizing of the optical system. In addition, when the moving amount of the lens group responsible for zooming increases, focus movement and aberration variation generated upon zooming become large, and thus optical performance deteriorates.

The lower limit of the conditional expression (1) may be set as follows: preferably 5.0 or more, more preferably 6.0 or more, more preferably 7.0 or more, more preferably 8.0 or more, more preferably 8.5 or more, more preferably 8.9 or more. The upper limit value of the conditional expression (1) may be set as follows: preferably 19.0 or less, more preferably 18.0 or less, more preferably 17.0 or less, more preferably 16.0 or less, more preferably 15.5 or less, more preferably 15.0 or less.

Next, when the focal length of the zoom lens at the telephoto end is denoted by Ft and the focal length of the 2 nd lens group is denoted by F2, the following conditional expressions are preferably satisfied.

(2)0.7≦|F1/Ft|≦2.0

Conditional expression (2) is an expression that specifies the ratio between the focal length of the 1 st lens group and the focal length of the zoom lens at the telephoto end. By satisfying the conditional expression (2), a high zoom ratio can be achieved at the telephoto end, and good optical performance can be maintained.

If the refractive power of the 1 st lens group is less than the lower limit of the conditional expression (2), the refractive power becomes too strong, and it becomes difficult to correct curvature of field and astigmatism, and therefore, good optical performance cannot be maintained. On the other hand, in conditional expression (2), when it is larger than the upper limit thereof, the refractive power of the 1 st lens group becomes too weak, and in order to achieve a high zoom ratio, the moving amounts of the 2 nd lens group and the 3 rd lens group upon zooming are increased, and the entire length of the optical system is extended, so that it is difficult to achieve miniaturization of the optical system. In addition, when the moving amount of the lens group responsible for zooming increases, focus movement and aberration variation generated upon zooming become large, and thus optical performance deteriorates.

The lower limit of the conditional expression (2) may be set as follows: preferably 0.74 or more, and more preferably 0.78 or more. The upper limit of the conditional expression (2) may be set as follows: preferably 1.8 or less, more preferably 1.4 or less.

When the focal length of the zoom lens at the telephoto end is denoted by Ft and the focal length of the 3 rd lens group is denoted by F3, the following conditional expressions are preferably satisfied.

(3)1.9≦|F2/F3|≦5.0

Conditional expression (3) is an expression that specifies the ratio between the focal length of the 2 nd lens group and the focal length of the 3 rd lens group. By satisfying the conditional expression (3), a high zoom ratio can be achieved even if the moving amounts of the 2 nd lens group and the 3 rd lens group upon zooming are reduced. As a result, the movement of focus and aberration variation occurring during zooming are suppressed, and good optical performance can be maintained, and the overall length of the optical system can be kept short, thereby enabling miniaturization of the optical system.

In conditional expression (3), when less than the lower limit thereof, the refractive power of the 2 nd lens group becomes excessively stronger than that of the 3 rd lens group, and it becomes difficult to correct spherical aberration, axial chromatic aberration in the entire zoom region, and thus good optical performance cannot be maintained. On the other hand, in conditional expression (3), when it is larger than the upper limit thereof, the refractive power of the 3 rd lens group becomes excessively stronger than that of the 2 nd lens group, and it becomes difficult to correct curvature of field and astigmatism in the entire zoom region, and thus good optical performance cannot be maintained.

The lower limit of the conditional expression (3) may be set as follows: preferably 2.0 or more, more preferably 2.5 or more. The upper limit of the conditional expression (3) may be set as follows: preferably 4.5 or less, more preferably 4.0 or less, and more preferably 3.6 or less.

The above-described effects can be achieved by satisfying the respective conditional expressions. Further, by satisfying the conditional expressions (1) to (3), a compact and high-performance zoom lens having a high zoom ratio and maintaining good optical performance over the entire zoom region can be realized.

Further, in the zoom lens of the present invention, when a lateral magnification of the 3 rd lens group at the telephoto end is β 3t and a lateral magnification of the 3 rd lens group at the wide-angle end is β 3w, it is preferable that the following conditional expression is satisfied.

(4)3.0≦|β3t/β3w|≦9.0

Conditional expression (4) is an expression specifying a ratio of lateral magnifications of the 3 rd lens group at the wide-angle end to the telephoto end, and shows a ratio of zooming of the 3 rd lens group. By satisfying the conditional expression (4), a high zoom ratio can be achieved even if the moving amounts of the 2 nd lens group and the 3 rd lens group upon zooming are reduced. As a result, the movement of focus and aberration variation occurring during zooming are suppressed, and good optical performance can be maintained, and the overall length of the optical system can be kept short, thereby enabling miniaturization of the optical system.

In conditional expression (4), when less than the lower limit thereof, since the proportion of zooming of the 3 rd lens group decreases, it is necessary to increase the proportion of zooming of the other lens group responsible for zooming, so that the moving amount of the other lens group responsible for zooming increases. As a result, it is difficult to miniaturize the optical system. On the other hand, in conditional expression (4), if it is larger than the upper limit, the ratio of zooming of the 3 rd lens group increases, and it is difficult to correct curvature of field and astigmatism in the entire zoom region, and therefore, good optical performance cannot be maintained.

The lower limit of the conditional expression (4) may be set as follows: preferably 3.2 or more, more preferably 3.4 or more. The upper limit value of the conditional expression (4) may be set as follows: preferably 8.0 or less, more preferably 7.0 or less, more preferably 6.5 or less, more preferably 6.0 or less, more preferably 5.5 or less, more preferably 5.0 or less.

In the zoom lens according to the present invention, it is preferable that the subsequent lens group includes: a 4 th lens group having positive refractive power and a 5 th lens group having positive refractive power, which are arranged in order from the object side.

Further, it is preferable that either one of the 4 th lens group or the 5 th lens group is moved along the optical axis at the time of zooming. At this time, when the lateral magnification of the movable group in the subsequent lens group at the telephoto end is set to β pt and the lateral magnification of the movable group in the subsequent lens group at the wide-angle end is set to β pw, it is preferable that the following conditional expression is satisfied.

(5)3.0≦|βpt/βpw|≦10.0

Conditional expression (5) is an expression that specifies the ratio of the lateral magnification of the movable group in the subsequent lens group at the wide-angle end to the telephoto end, and shows the proportion of zooming of the movable group. By satisfying the conditional expression (5), a high zoom ratio can be realized while suppressing the amount of movement of the movable group during zooming. As a result, the movement of focus and aberration variation occurring during zooming are suppressed, and good optical performance can be maintained, and the overall length of the optical system can be kept short, thereby enabling miniaturization of the optical system.

In conditional expression (5), when less than the lower limit thereof, since the proportion of zooming of the movable group in the subsequent lens group decreases, it is necessary to increase the proportion of zooming of the other lens group responsible for zooming, so that the moving amount of the other lens group responsible for zooming increases. As a result, it is difficult to downsize the optical system particularly when a high zoom ratio is to be achieved. On the other hand, in conditional expression (5), when it is larger than the upper limit thereof, the ratio of zooming of the movable group in the subsequent lens group increases, and it becomes difficult to correct curvature of field and astigmatism in the entire zoom region, and thus good optical performance cannot be maintained.

The lower limit of the conditional expression (5) may be set as follows: preferably 3.4 or more, more preferably 3.9 or more. The upper limit of the conditional expression (5) may be set as follows: preferably 9.0 or less, more preferably 8.0 or less, more preferably 7.0 or less, more preferably 6.7 or less, more preferably 6.2 or less.

Further, it is preferable that, at the time of zooming, any one of the 4 th lens group or the 5 th lens group among lens groups included in the subsequent lens groups is a movable group. By setting any one of the lens groups as a movable group, the zoom mechanism can be simplified, and the optical system can be downsized. In addition, when the subsequent lens group is composed of 2 lens groups, either one of the 4 th lens group and the 5 th lens group may be a movable group. When the subsequent lens group is composed of 3 or more lens groups and the lens group disposed on the image side of the 5 th lens (the 6 th lens group) is fixed on the optical axis upon zooming, it is preferable that the 5 th lens group is set as a movable group, the 4 th lens group is fixed on the optical axis upon zooming, and when the lens group disposed on the image side of the 5 th lens (the 6 th lens group) is movable upon zooming, either the 4 th lens group or the 5 th lens group may be set as a movable group.

In the zoom lens of the present invention, it is preferable that the 1 st lens group is composed of 1 lens. Since the outer diameter of the 1 st lens group tends to increase, the 1 st lens group is constituted by 1 lens, so that the 1 st lens group can be reduced in weight, and the 1 st lens group can be made thin and the total length of the optical system can be kept short, thereby achieving downsizing of the optical system. Further, since the 1 st lens group is composed of 1 lens, a mechanism for holding the 1 st lens group can be simplified. The lens constituting the 1 st lens group may have a negative refractive power, and may have a meniscus shape or a biconcave shape. However, to produce a strong negative refractive power, a biconcave shape is preferred.

In the zoom lens of the present invention, it is preferable that a 6 th lens group having a positive refractive power is disposed on an image surface side of a 5 th lens group in the subsequent lens groups. By so doing, various aberrations such as curvature of field that are not completely corrected before passing through the 5 th lens group can be effectively corrected, and a zoom lens having higher resolution in the entire zoom region can be realized.

Further, in the zoom lens of the present invention, it is preferable that, upon zooming from the wide-angle end to the telephoto end, the interval between the 1 st lens group and the 2 nd lens group is maximized at an intermediate region of the zooming. Here, the intermediate zoom region is a region in the middle of zooming from the wide-angle end to the telephoto end, and may be any focal length other than the wide-angle end and the telephoto end. By adopting such a configuration of the lens groups at the time of zooming, a high zoom ratio can be achieved.

Further, in the zoom lens of the present invention, it is preferable that the stop is disposed in the 4 th lens group. Further, in the case where the diaphragm moves together with the 4 th lens group upon zooming, or the 4 th lens group is fixed on the optical axis upon zooming, it is preferable that the diaphragm is also fixed. Here, the stop disposed in the 4 th lens group means that the stop is disposed on any one of the object side, the image side of the 4 th lens group, and the lens disposed in the 4 th lens group, and the position of the disposed stop is not particularly limited if the stop is configured to move or be fixed along the optical axis direction together with the 4 th lens group. By disposing the stop in the 4 th lens group, aberration variation during zooming can be suppressed, and high performance can be achieved.

In the zoom lens of the present invention, it is preferable that the 3 rd lens group is moved to the image side upon zooming from the wide-angle end to the telephoto end. By adopting such a configuration of the lens groups at the time of zooming, a high zoom ratio can be achieved.

As described above, according to the present invention, by having the above-described configuration, a compact and high-performance zoom lens having a high zoom ratio and maintaining good optical performance over the entire zoom region can be realized. The zoom lens is a lens having high optical performance and is particularly suitable for an imaging device having a solid-state imaging element with high pixel density.

Another object of the present invention is to provide an imaging apparatus having a compact and high-performance zoom lens with a high zoom ratio. To achieve this object, the imaging device is configured to include: the zoom lens having the above configuration and the solid-state imaging device that converts an optical image formed by the zoom lens into an electric signal may be provided. By doing so, an imaging apparatus of high resolution can be realized.

Hereinafter, embodiments of the zoom lens of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following examples.

[ example 1 ]

Fig. 1 shows a cross-sectional view along an optical axis showing a structure of a zoom lens of embodiment 1. The zoom lens is configured to have, arranged in order from an object side not shown: 1 st lens group G having negative refractive power₁And a 2 nd lens group G having positive refractive power₂And a 3 rd lens group G with positive refractive power₃And the subsequent lens group G_R. In the 3 rd lens group G₃And a subsequent lens group G_RAn aperture stop STP having a predetermined aperture is disposed between the first and second diaphragms. In the subsequent lens group G_RAnd cover glass CG is arranged between the image plane IMG and the image plane. The cover glass CG is disposed as required.

In addition, the subsequent lens group G_RThe image pickup device is configured to dispose, in order from an object side: group 4G having positive refractive power₄And a 5 th lens group G having positive refractive power₅And a 6 th lens group G having positive refractive power₆。

Group 1 lens G₁Is composed of a biconcave negative lens L only₁₁And (3) forming.

Group 2 lens G₂The image pickup device is configured to dispose, in order from an object side: negative meniscus lens L with convex surface facing the object side₂₁Biconvex positive lens L₂₂And a biconvex positive lens L₂₃. Negative meniscus lens L₂₁And a biconvex positive lens L₂₂And (4) bonding. In the biconvex positive lens L₂₃Are formed with aspherical surfaces.

Group 3 lens G₃The image pickup device is configured to dispose, in order from an object side: biconcave negative lens L₃₁Double concave negative lens L₃₂Biconvex positive lens L₃₃And a negative meniscus lens L with the convex surface facing the image side₃₄. In the biconcave negative lens L₃₁Are formed with aspherical surfaces. Biconvex positive lens L₃₃And a negative meniscus lens L₃₄And (4) bonding.

Group 4 lens G₄The image pickup device is configured to dispose, in order from an object side: biconvex positive lens L₄₁And a negative meniscus lens with the convex surface facing the image sideL₄₂. Biconvex positive lens L₄₁And a negative meniscus lens L₄₂And (4) bonding.

Group 5 lens G₅The image pickup device is configured to dispose, in order from an object side: biconvex positive lens L₅₁Biconvex positive lens L₅₂Double concave negative lens L₅₃Biconvex positive lens L₅₄Negative meniscus lens L with convex surface facing the object side₅₅Biconvex positive lens L₅₆And a negative meniscus lens L with the convex surface facing the image side₅₇. In the biconvex positive lens L₅₁Are formed with aspherical surfaces. Biconvex positive lens L₅₂Double concave negative lens L₅₃And a biconvex positive lens L₅₄And (4) bonding. Negative meniscus lens L₅₅Biconvex positive lens L₅₆And a negative meniscus lens L₅₇And (4) bonding.

Group 6 lens G₆The image pickup device is configured to dispose, in order from an object side: negative meniscus lens L with convex surface facing the object side₆₁And a positive meniscus lens L with the convex surface facing the object side₆₂。

The zoom lens keeps the 1 st lens group G at all times when zooming from the wide-angle end to the telephoto end₁Group 4, group G₄And the 6 th lens group G₆In a state of being fixed with respect to the image plane IMG, the 2 nd lens group G₂Moving along the optical axis so as to form a convex locus on the image plane IMG side, and a 3 rd lens group G₃Monotonously moving from object side to image surface IMG side along optical axis, 5 th lens group G₅Monotonously moving from the image plane IMG side to the object side along the optical axis.

Hereinafter, various numerical data relating to the zoom lens of embodiment 1 are shown.

(surface data)

r₁＝-258.600

d₁＝1.300 nd₁＝1.8042 νd₁＝46.50

r₂＝39.170

d₂Either D (2) (variable)

r₃＝56.700

d₃＝0.900 nd₂＝1.8548 νd₂＝24.80

r₄＝31.260

d₄＝5.700 nd₃＝1.4970 νd₃＝81.61

r₅＝-79.000

d₅＝0.150

r₆30.850 (aspherical)

d₆＝5.000 nd₄＝1.6935 νd₄＝53.20

r₇= 96.512 (aspherical)

d₇Either as D (7) (variable)

r₈= 103.233 (aspherical)

d₈＝0.600 nd₅＝1.8514 νd₅＝40.10

r₉10.784 (aspherical)

d₉＝3.441

r₁₀＝-10.850

d₁₀＝0.600 nd₆＝1.6385 νd₆＝55.45

r₁₁＝186.000

d₁₁＝0.176

r₁₂＝76.800

d₁₂＝2.310 nd₇＝1.9229 νd₇＝20.88

r₁₃＝-16.960

d₁₃＝0.600 nd₈＝1.7292 νd₈＝54.67

r₁₄＝-88.880

d₁₄Either D (14) (variable)

r₁₅Infinity (aperture stop)

d₁₅＝0.600

r₁₆＝39.720

d₁₆＝4.210 nd₉＝1.4970 νd₉＝81.61

r₁₇＝-19.300

d₁₇＝0.600 nd₁₀＝1.8042 νd₁₀＝46.50

r₁₈＝-40.040

d₁₈Either as D (18) (variable)

r₁₉48.511 (aspherical)

d₁₉＝3.200 nd₁₁＝1.6935 νd₁₁＝53.20

r₂₀= 68.078 (aspherical)

d₂₀＝0.150

r₂₁＝15.300

d₂₁＝7.440 nd₁₂＝1.4970 νd₁₂＝81.61

r₂₂＝-15.300

d₂₂＝1.000 nd₁₃＝1.8061 νd₁₃＝40.73

r₂₃＝118.600

d₂₃＝3.480 nd₁₄＝1.8081 νd₁₄＝22.76

r₂₄＝-30.260

d₂₄＝0.150

r₂₅＝26.300

d₂₅＝1.000 nd₁₅＝2.0010 νd₁₅＝29.13

r₂₆＝8.672

d₂₆＝5.290 nd₁₆＝1.4970 νd₁₆＝81.61

r₂₇＝-12.864

d₂₇＝0.600 nd₁₇＝1.6204 νd₁₇＝60.34

r₂₈＝-49.000

d₂₈Either D (28) (variable)

r₂₉＝46.000

d₂₉＝0.600 nd₁₈＝1.9037 νd₁₈＝31.31

r₃₀＝18.300

d₃₀＝2.711

r₃₁＝20.440

d₃₁＝2.250 nd₁₉＝1.6968 νd₁₉＝55.46

r₃₂＝126.500

d₃₂＝4.400

r₃₃＝∞

d₃₃＝1.000 nd₂₀＝1.5163 νd₂₀＝64.14

r₃₄＝∞

d₃₄＝1.000

r₃₅Infinity (image plane)

Conic coefficient (k) and aspherical coefficient (A)₄，A₆，A₈，A₁₀，A₁₂，A₁₄)

(item 6)

k＝0，

A₄＝-2.8400×10^-6，A₆＝3.9875×10^-8，

A₈＝-4.8993×10^-10，A₁₀＝8.6640×10^-12，

A₁₂＝-6.7380×10^-14，A₁₄＝2.2082×10^-16

(7 th plane)

k＝0，

A₄＝3.3475×10^-7，A₆＝1.0920×10^-8，

A₈＝3.7294×10^-10，A₁₀＝-1.5000×10^-12，

A₁₂＝-1.2478×10^-14，A₁₄＝1.1593×10^-16

(item 8)

k＝0，

A₄＝1.3969×10^-5，A₆＝-1.3224×10^-7，

A₈＝6.1860×10^-9，A₁₀＝-1.0476×10^-10，

A₁₂＝0，A₁₄＝0

(item 9 th)

k＝0，

A₄＝4.9520×10^-6，A₆＝-7.5303×10^-7，

A₈＝5.6418×10^-8，A₁₀＝-7.6164×10^-10，

A₁₂＝0，A₁₄＝0

(side 19)

k＝0，

A₄＝7.6863×10^-6，A₆＝-1.0741×10^-8，

A₈＝2.1915×10^-9，A₁₀＝-1.7507×10^-11，

A₁₂＝-1.2945×10^-14，A₁₄＝0

(side 20)

k＝0，

A₄＝2.0382×10^-5，A₆＝-8.9746×10^-8，

A₈＝3.1841×10^-9，A₁₀＝-3.1291×10^-11，

A₁₂＝2.2543×10^-14，A₁₄＝0

(various data)

(zoom lens group data)

(numerical values relating to conditional expression (1))

|F1/Fw|＝9.86

(numerical values relating to conditional expression (2))

|F1/Ft|＝0.87

(numerical values relating to conditional expression (3))

|F2/F3|＝3.16

(numerical values related to conditional expression (4))

Beta 3t (group G of lens 3)₃Transverse magnification at the telephoto end) — 0.85

Beta 3w (group G of lens 3)₃Transverse magnification at wide-angle end) — 0.24

|β3t/β3w|＝3.49

(numerical values relating to conditional expression (5))

β pt (movable group in subsequent lens group (5 th lens group G)₅) Transverse magnification at the telephoto end) — 0.86

β pw (movable group in subsequent lens group (5 th lens group G)₅) Transverse magnification at wide-angle end) — 0.14

|βpt/βpw|＝6.09

Fig. 2 shows various aberration diagrams of the zoom lens of embodiment 1. In the spherical aberration diagram, the vertical axis represents the F number (represented by FNO in the figure), the solid line represents the characteristic corresponding to the wavelength of the d line (587.56nm), the one-dot chain line represents the characteristic corresponding to the wavelength of the C line (656.28nm), and the broken line represents the characteristic corresponding to the wavelength of the F line (486.13 nm). In the astigmatism diagram, the vertical axis represents a half field angle (denoted by ω in the diagram), and shows a characteristic corresponding to a wavelength of a d-line. In the astigmatism diagram, a solid line shows a characteristic of a radial plane (denoted by S in the diagram), and a broken line shows a characteristic of a meridional plane (denoted by M in the diagram). In the distortion aberration diagram, the vertical axis represents a half field angle (denoted by ω in the drawing), and shows a characteristic corresponding to the wavelength of the d-line.

[ example 2 ]

Fig. 3 shows a cross-sectional view along the optical axis showing the structure of a zoom lens of embodiment 2. The optical structure of the zoom lens of this embodiment and the movement of each lens group upon zooming are the same as those of the zoom lens shown in embodiment 1. Therefore, in the present embodiment, the same components as those of embodiment 1 are assigned the same reference numerals, and detailed description thereof is omitted.

Hereinafter, various numerical data relating to the zoom lens of embodiment 2 are shown.

(surface data)

r₁＝-128.642

d₁＝1.300 nd₁＝1.8042 νd₁＝46.50

r₂＝86.633

d₂Either D (2) (variable)

r₃＝97.555

d₃＝0.900 nd₂＝1.8548 νd₂＝24.80

r₄＝40.754

d₄＝5.700 nd₃＝1.4970 νd₃＝81.61

r₅＝-81.000

d₅＝0.150

r₆33.462 (aspherical)

d₆＝5.000 nd₄＝1.6935 νd₄＝53.20

r₇= 105.004 (aspherical)

d₇Either as D (7) (variable)

r₈= 184.258 (aspherical)

d₈＝0.600 nd₅＝1.8514 νd₅＝40.10

r₉9.660 (aspherical)

d₉＝3.441

r₁₀＝-12.151

d₁₀＝0.600 nd₆＝1.6385 νd₆＝55.45

r₁₁＝67.822

d₁₁＝0.176

r₁₂＝40.190

d₁₂＝2.310 nd₇＝1.9229 νd₇＝20.88

r₁₃＝-21.037

d₁₃＝0.600 nd₈＝1.7292 νd₈＝54.67

r₁₄＝-106.143

d₁₄Either D (14) (variable)

r₁₅Infinity (aperture stop)

d₁₅＝0.600

r₁₆＝35.038

d₁₆＝4.210 nd₉＝1.4970 νd₉＝81.61

r₁₇＝-22.407

d₁₇＝0.600 nd₁₀＝1.8042 νd₁₀＝46.50

r₁₈＝-67.185

d₁₈Either as D (18) (variable)

r₁₉39.835 (aspherical)

d₁₉＝3.200 nd₁₁＝1.6935 νd₁₁＝53.20

r₂₀= 80.656 (aspherical)

d₂₀＝0.150

r₂₁＝15.683

d₂₁＝7.440 nd₁₂＝1.4970 νd₁₂＝81.61

r₂₂＝-15.929

d₂₂＝1.000 nd₁₃＝1.8061 νd₁₃＝40.73

r₂₃＝115.784

d₂₃＝3.480 nd₁₄＝1.8081 νd₁₄＝22.76

r₂₄＝-31.156

d₂₄＝0.150

r₂₅＝24.351

d₂₅＝1.000 nd₁₅＝2.0010 νd₁₅＝29.13

r₂₆＝8.639

d₂₆＝5.290 nd₁₆＝1.4970 νd₁₆＝81.61

r₂₇＝-13.086

d₂₇＝0.600 nd₁₇＝1.6204 νd₁₇＝60.34

r₂₈＝-43.515

d₂₈Either D (28) (variable)

r₂₉＝15.050

d₂₉＝0.600 nd₁₈＝1.9037 νd₁₈＝31.31

r₃₀＝9.741

d₃₀＝2.711

r₃₁＝15.775

d₃₁＝2.250 nd₁₉＝1.6968 νd₁₉＝55.46

r₃₂＝50.681

d₃₂＝4.400

r₃₃＝∞

d₃₃＝1.000 nd₂₀＝1.5163 νd₂₀＝64.14

r₃₄＝∞

d₃₄＝1.000

r₃₅Infinity (image plane)

(item 6)

k＝0，

A₄＝-2.7204×10^-6，A₆＝4.0454×10^-8，

A₈＝-4.6815×10^-10，A₁₀＝8.5225×10^-12，

A₁₂＝-6.9515×10^-14，A₁₄＝2.2082×10^-16

(7 th plane)

k＝0，

A₄＝1.0655×10^-6，A₆＝1.5711×10^-8，

A₈＝3.6582×10^-10，A₁₀＝-1.8761×10^-12，

A₁₂＝-1.3073×10^-14，A₁₄＝1.1593×10^-16

(item 8)

k＝0，

A₄＝-2.3816×10^-7，A₆＝-2.2000×10^-7，

A₈＝8.6543×10^-9，A₁₀＝-1.1481×10^-10，

A₁₂＝0，A₁₄＝0

(item 9 th)

k＝0，

A₄＝-2.4723×10^-5，A₆＝-1.7377×10^-6，

A₈＝7.4493×10^-8，A₁₀＝-1.1663×10^-9，

A₁₂＝0，A₁₄＝0

(side 19)

k＝0，

A₄＝4.9385×10^-6，A₆＝-1.2067×10^-8，

A₈＝2.2353×10^-9，A₁₀＝-1.8036×10^-11，

A₁₂＝-1.2945×10^-14，A₁₄＝0

(side 20)

k＝0，

A₄＝2.2832×10^-5，A₆＝-8.0148×10^-8，

A₈＝3.1887×10^-9，A₁₀＝-3.1279×10^-11，

A₁₂＝2.2543×10^-14，A₁₄＝0

(various data)

(zoom lens group data)

(numerical values relating to conditional expression (1))

|F1/Fw|＝15.00

(numerical values relating to conditional expression (2))

|F1/Ft|＝1.33

(numerical values relating to conditional expression (3))

|F2/F3|＝3.57

(numerical values related to conditional expression (4))

Beta 3t (group G of lens 3)₃Transverse magnification at the telephoto end) — 0.88

|β3t/β3w|＝3.66

(numerical values relating to conditional expression (5))

β pt (movable group in subsequent lens group (5 th lens group G)₅) Transverse magnification at the telephoto end) — 0.91

β pw (movable group in subsequent lens group (5 th lens group G)₅) Transverse magnification at wide-angle end) — 0.21

|βpt/βpw|＝4.33

Fig. 4 shows various aberration diagrams of the zoom lens of embodiment 2. In the spherical aberration diagram, the vertical axis represents the F number (represented by FNO in the figure), the solid line represents the characteristic corresponding to the wavelength of the d line (587.56nm), the one-dot chain line represents the characteristic corresponding to the wavelength of the C line (656.28nm), and the broken line represents the characteristic corresponding to the wavelength of the F line (486.13 nm). In the astigmatism diagram, the vertical axis represents a half field angle (denoted by ω in the diagram), and shows a characteristic corresponding to a wavelength of a d-line. In the astigmatism diagram, a solid line shows a characteristic of a radial plane (denoted by S in the diagram), and a broken line shows a characteristic of a meridional plane (denoted by M in the diagram). In the distortion aberration diagram, the vertical axis represents a half field angle (denoted by ω in the drawing), and shows a characteristic corresponding to the wavelength of the d-line.

[ example 3 ]

Fig. 5 shows a cross-sectional view along the optical axis showing the structure of a zoom lens of embodiment 3. The optical structure of the zoom lens of this embodiment and the movement of each lens group upon zooming are the same as those of the zoom lens shown in embodiment 1. Therefore, in the present embodiment, the same components as those of embodiment 1 are assigned the same reference numerals, and detailed description thereof is omitted.

Hereinafter, various numerical data relating to the zoom lens of embodiment 3 are shown.

(surface data)

r₁＝-106.965

d₁＝1.300 nd₁＝1.8042 νd₁＝46.50

r₂＝43.788

d₂Either D (2) (variable)

r₃＝69.161

d₃＝0.900 nd₂＝1.8548 νd₂＝24.80

r₄＝35.650

d₄＝5.700 nd₃＝1.4970 νd₃＝81.61

r₅＝-64.651

d₅＝0.150

r₆34.803 (aspherical)

d₆＝5.000 nd₄＝1.6935 νd₄＝53.20

r₇= 69.145 (aspherical)

d₇Either as D (7) (variable)

r₈= 75.672 (aspherical)

d₈＝0.600 nd₅＝1.8514 νd₅＝40.10

r₉11.109 (aspherical)

d₉＝3.441

r₁₀＝-11.051

d₁₀＝0.600 nd₆＝1.6385 νd₆＝55.45r₁₁＝72.120

d₁₁＝0.176

r₁₂＝54.292

d₁₂＝2.310 nd₇＝1.9229 νd₇＝20.88

r₁₃＝-21.981

d₁₃＝0.600 nd₈＝1.7292 νd₈＝54.67

r₁₄＝-31.329

d₁₄Either D (14) (variable)

r₁₅Infinity (aperture stop)

d₁₅＝0.600

r₁₆＝38.054

d₁₆＝4.210 nd₉＝1.4970 νd₉＝81.61

r₁₇＝-30.804

d₁₇＝0.600 nd₁₀＝1.8042 νd₁₀＝46.50

r₁₈＝-134.701

d₁₈Either as D (18) (variable)

r₁₉36.618 (aspherical)

d₁₉＝3.200 nd₁₁＝1.6935 νd₁₁＝53.20

r₂₀= 102.581 (aspherical)

d₂₀＝0.150

r₂₁＝14.586

d₂₁＝7.440 nd₁₂＝1.4970 νd₁₂＝81.61

r₂₂＝-16.933

d₂₂＝1.000 nd₁₃＝1.8061 νd₁₃＝40.73

r₂₃＝70.311

d₂₃＝3.480 nd₁₄＝1.8081 νd₁₄＝22.76

r₂₄＝-34.965

d₂₄＝0.150

r₂₅＝23.865

d₂₅＝1.000 nd₁₅＝2.0010 νd₁₅＝29.13

r₂₆＝7.955

d₂₆＝5.290 nd₁₆＝1.4970 νd₁₆＝81.61

r₂₇＝-15.619

d₂₇＝0.600 nd₁₇＝1.6204 νd₁₇＝60.34

r₂₈＝-66.177

d₂₈Either D (28) (variable)

r₂₉＝13.302

d₂₉＝0.600 nd₁₈＝1.9037 νd₁₈＝31.31

r₃₀＝10.303

d₃₀＝2.711

r₃₁＝23.890

d₃₁＝2.250 nd₁₉＝1.6968 νd₁₉＝55.46

r₃₂＝78.008

d₃₂＝4.400

r₃₃＝∞

d₃₃＝1.000 nd₂₀＝1.5163 νd₂₀＝64.14

r₃₄＝∞

d₃₄＝1.000

r₃₅Infinity (image plane)

(item 6)

k＝0，

A₄＝-2.7204×10^-6，A₆＝4.0454×10^-8，

A₈＝-4.6815×10^-10，A₁₀＝8.5225×10^-12，

A₁₂＝-6.9515×10^-14，A₁₄＝2.2082×10^-16

(7 th plane)

k＝0，

A₄＝1.0655×10^-6，A₆＝1.5711×10^-8，

A₈＝3.6582×10^-10，A₁₀＝-1.8761×10^-12，

A₁₂＝-1.3073×10^-14，A₁₄＝1.1593×10^-16

(item 8)

k＝0，

A₄＝-2.3816×10^-7，A₆＝-2.2000×10^-7，

A₈＝8.6543×10^-9，A₁₀＝-1.1481×10^-10，

A₁₂＝0，A₁₄＝0

(item 9 th)

k＝0，

A₄＝-2.4723×10^-5，A₆＝-1.7377×10^-6，

A₈＝7.4493×10^-8，A₁₀＝-1.1663×10^-9，

A₁₂＝0，A₁₄＝0

(side 19)

k＝0，

A₄＝4.9385×10^-6，A₆＝-1.2067×10^-8，

A₈＝2.2353×10^-9，A₁₀＝-1.8036×10^-11，

A₁₂＝-1.2945×10^-14，A₁₄＝0

(side 20)

k＝0，

A₄＝2.2832×10^-5，A₆＝-8.0148×10^-8，

A₈＝3.1887×10^-9，A₁₀＝-3.1279×10^-11，

A₁₂＝2.2543×10^-14，A₁₄＝0

(various data)

(zoom lens group data)

(numerical values relating to conditional expression (1))

|F1/Fw|＝8.99

(numerical values relating to conditional expression (2))

|F1/Ft|＝0.80

(numerical values relating to conditional expression (3))

|F2/F3|＝2.60

(numerical values related to conditional expression (4))

Beta 3t (group G of lens 3)₃Transverse magnification at the telephoto end) — 0.94

Beta 3w (group G of lens 3)₃Transverse magnification at wide-angle end) — 0.26

|β3t/β3w|＝3.59

(numerical values relating to conditional expression (5))

β pt (movable group in subsequent lens group (5 th lens group G)₅) Transverse magnification at the telephoto end) — 0.96

β pw (movable group in subsequent lens group (5 th lens group G)₅) Transverse magnification at wide-angle end) — 0.24

|βpt/βpw|＝4.05

Fig. 6 shows various aberration diagrams of the zoom lens of embodiment 3. In the spherical aberration diagram, the vertical axis represents the F number (represented by FNO in the figure), the solid line represents the characteristic corresponding to the wavelength of the d line (587.56nm), the one-dot chain line represents the characteristic corresponding to the wavelength of the C line (656.28nm), and the broken line represents the characteristic corresponding to the wavelength of the F line (486.13 nm). In the astigmatism diagram, the vertical axis represents a half field angle (denoted by ω in the diagram), and shows a characteristic corresponding to a wavelength of a d-line. In the astigmatism diagram, a solid line shows a characteristic of a radial plane (denoted by S in the diagram), and a broken line shows a characteristic of a meridional plane (denoted by M in the diagram). In the distortion aberration diagram, the vertical axis represents a half field angle (denoted by ω in the drawing), and shows a characteristic corresponding to the wavelength of the d-line.

[ example 4 ]

Fig. 7 is a cross-sectional view along the optical axis showing the structure of a zoom lens of example 4. The optical structure of the zoom lens of the present embodiment and the movement of each lens group upon zooming, except for the 6 th lens group G₆Middle configured biconvex positive lens L₄₆₂Instead of the positive meniscus lens L₆₂Except for this point, the zoom lens is the same as that of embodiment 1. Therefore, in the present embodiment, the same components as those of embodiment 1 are assigned the same reference numerals, and detailed description thereof is omitted.

Hereinafter, various numerical data relating to the zoom lens of embodiment 4 are shown.

(surface data)

r₁＝-87.698

d₁＝1.300 nd₁＝1.8042 νd₁＝46.50

r₂＝52.797

d₂Either D (2) (variable)

r₃＝93.413

d₃＝0.900 nd₂＝1.8548 νd₂＝24.80

r₄＝37.838

d₄＝5.700 nd₃＝1.4970 νd₃＝81.61

r₅＝-53.869

d₅＝0.150

r₆33.677 (aspherical)

d₆＝5.000 nd₄＝1.6935 νd₄＝53.20

r₇= 67.360 (aspherical)

d₇Either as D (7) (variable)

r₈= 70.691 (aspherical)

d₈＝0.600 nd₅＝1.8514 νd₅＝40.10

r₉10.250 (aspherical)

d₉＝3.441

r₁₀＝-11.717

d₁₀＝0.600 nd₆＝1.6385 νd₆＝55.45

r₁₁＝80.294

d₁₁＝0.176

r₁₂＝43.624

d₁₂＝2.310 nd₇＝1.9229 νd₇＝20.88

r₁₃＝-24.524

d₁₃＝0.600 nd₈＝1.7292 νd₈＝54.67

r₁₄＝-46.616

d₁₄Either D (14) (variable)

r₁₅Infinity (aperture stop)

d₁₅＝0.600

r₁₆＝36.940

d₁₆＝4.210 nd₉＝1.4970 νd₉＝81.61

r₁₇＝-37.184

d₁₇＝0.600 nd₁₀＝1.8042 νd₁₀＝46.50

r₁₈＝-82.098

d₁₈Either as D (18) (variable)

r₁₉43.988 (aspherical)

d₁₉＝3.200 nd₁₁＝1.6935 νd₁₁＝53.20

r₂₀= 92.518 (aspherical)

d₂₀＝0.150

r₂₁＝14.558

d₂₁＝7.440 nd₁₂＝1.4970 νd₁₂＝81.61

r₂₂＝-17.048

d₂₂＝1.000 nd₁₃＝1.8061 νd₁₃＝40.73

r₂₃＝63.629

d₂₃＝3.480 nd₁₄＝1.8081 νd₁₄＝22.76

r₂₄＝-33.337

d₂₄＝0.150

r₂₅＝26.905

d₂₅＝1.000 nd₁₅＝2.0010 νd₁₅＝29.13

r₂₆＝8.052

d₂₆＝5.290 nd₁₆＝1.4970 νd₁₆＝81.61

r₂₇＝-14.799

d₂₇＝0.600 nd₁₇＝1.6204 νd₁₇＝60.34

r₂₈＝-49.354

d₂₈Either D (28) (variable)

r₂₉＝18.620

d₂₉＝0.600 nd₁₈＝1.9037 νd₁₈＝31.31

r₃₀＝9.463

d₃₀＝2.711

r₃₁＝15.084

d₃₁＝2.250 nd₁₉＝1.6968 νd₁₉＝55.46

r₃₂＝-181.440

d₃₂＝4.400

r₃₃＝∞

d₃₃＝1.000 nd₂₀＝1.5163 νd₂₀＝64.14

r₃₄＝∞

d₃₄＝1.000

r₃₅Infinity (image plane)

(item 6)

k＝0，

A₄＝-4.2932×10^-6，A₆＝4.0241×10^-8，

A₈＝-4.7280×10^-10，A₁₀＝8.4476×10^-12，

A₁₂＝-6.7890×10^-14，A₁₄＝2.1651×10^-16

(7 th plane)

k＝0，

A₄＝4.1939×10^-7，A₆＝8.9980×10^-9，

A₈＝4.0304×10^-10，A₁₀＝-1.6528×10^-12，

A₁₂＝-1.5116×10^-14，A₁₄＝1.1739×10^-16

(item 8)

k＝0，

A₄＝-3.9949×10^-6，A₆＝1.8192×10^-7，

A₈＝2.0321×10^-9，A₁₀＝-6.3171×10^-11，

A₁₂＝0，A₁₄＝0

(item 9 th)

k＝0，

A₄＝-3.8713×10^-5，A₆＝-1.0134×10^-6，

A₈＝5.2657×10^-8，A₁₀＝-7.4101×10^-10，

A₁₂＝0，A₁₄＝0

(side 19)

k＝0，

A₄＝4.7575×10^-6，A₆＝-4.5557×10^-8，

A₈＝2.1444×10^-9，A₁₀＝-1.7342×10^-11，

A₁₂＝-1.2945×10^-14，A₁₄＝0

(side 20)

k＝0，

A₄＝2.2402×10^-5，A₆＝-9.4619×10^-8，

A₈＝3.0257×10^-9，A₁₀＝-2.9738×10^-11，

A₁₂＝2.2543×10^-14，A₁₄＝0

(various data)

(zoom lens group data)

(numerical values relating to conditional expression (1))

|F1/Fw|＝9.54

(numerical values relating to conditional expression (2))

|F1/Ft|＝0.85

(numerical values relating to conditional expression (3))

|F2/F3|＝2.85

(numerical values related to conditional expression (4))

Beta 3t (group G of lens 3)₃Transverse magnification at the telephoto end) — 1.21

Beta 3w (group G of lens 3)₃Transverse magnification at wide-angle end) — 0.25

|β3t/β3w|＝4.90

(numerical values relating to conditional expression (5))

β pt (movable group in subsequent lens group (5 th lens group G)₅) Transverse magnification at telephoto end) — 0.63

β pw (movable group in subsequent lens group (5 th lens group G)₅) Transverse magnification at wide-angle end) — 0.11

|βpt/βpw|＝5.60

Fig. 8 shows various aberration diagrams of the zoom lens of embodiment 4. In the spherical aberration diagram, the vertical axis represents the F number (represented by FNO in the figure), the solid line represents the characteristic corresponding to the wavelength of the d line (587.56nm), the one-dot chain line represents the characteristic corresponding to the wavelength of the C line (656.28nm), and the broken line represents the characteristic corresponding to the wavelength of the F line (486.13 nm). In the astigmatism diagram, the vertical axis represents a half field angle (denoted by ω in the diagram), and shows a characteristic corresponding to a wavelength of a d-line. In the astigmatism diagram, a solid line shows a characteristic of a radial plane (denoted by S in the diagram), and a broken line shows a characteristic of a meridional plane (denoted by M in the diagram). In the distortion aberration diagram, the vertical axis represents a half field angle (denoted by ω in the drawing), and shows a characteristic corresponding to the wavelength of the d-line.

The following is a table showing the correspondence between conditional expressions in the above embodiments.

[ TABLE 1 ]

Examples	1	2	3	4
					Conditional formula 1	9.86	15.00	8.99	9.54
Conditional formula 2	0.87	1.33	0.80	0.85
					Conditional formula 3	3.16	3.57	2.60	2.85
Conditional formula 4	3.49	3.66	3.59	4.90
					Conditional formula 5	6.09	4.33	4.05	5.60

In addition, in the numerical data in the above embodiments, r is₁，r₂And … … denotes a radius of curvature of a lens surface or the like, d₁，d₂And … … denotes a wall thickness of a lens or the like or a surface interval between lenses, nd₁，nd₂… … denotes a refractive index of a lens or the like with respect to a d-line (λ 587.56nm), vd₁，νd₂And … … denotes an abbe number of the lens or the like with respect to the d-line (λ 587.56 nm). The length is expressed in units of "mm" and the angle is expressed in units of "°".

In addition, for each of the aspherical shapes, the height in the direction perpendicular to the optical axis is h, the amount of displacement in the optical axis direction of the height h with the vertex of the lens surface as the origin is X, the paraxial radius of curvature is R, the conic coefficient is k, and aspherical coefficients of 4 times, 6 times, 8 times, 10 times, 12 times, and 14 times are a₄，A₆，A₈，A₁₀，A₁₂，A₁₄When the image plane direction is a positive direction, the aspherical shapes can be expressed by the following formulas.

[ EQUATION 1 ]

As shown in the above embodiments, by satisfying the above conditional expressions, a small and high-performance zoom lens having a high zoom ratio and maintaining good optical performance over the entire zoom region can be realized.

< application example >

Next, an example in which the zoom lens of the present invention is applied to an image pickup apparatus is shown. Fig. 9 is a diagram showing an example of an imaging apparatus including the zoom lens of the present invention. As shown in fig. 9, the imaging apparatus 100 is constituted by a lens barrel portion 11 in which a zoom lens 10 is housed and a camera body 21 having a solid-state imaging device 20. The zoom lens 10 is driven by a mechanical mechanism not shown to perform zooming and the like. In fig. 9, the zoom lens of example 1 (see fig. 1) is shown as the zoom lens 10, but the zoom lenses of examples 2 to 4 can be similarly mounted on the image pickup apparatus 100.

In the imaging apparatus 100 having the zoom lens 10 and the solid-state imaging element 20, an image plane IMG shown in fig. 1 corresponds to an imaging plane of the solid-state imaging element 20. As the solid-state imaging Device 20, for example, a photoelectric conversion Device such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) can be used.

In the image pickup apparatus 100, light incident from the object side of the zoom lens 10 is finally imaged on the imaging surface of the solid-state image pickup device 20. The solid-state imaging element 20 photoelectrically converts the received light and outputs the converted light as an electric signal. The output signal is subjected to calculation processing by a signal processing circuit, not shown, and a digital image corresponding to the object image is generated. The digital image can be recorded on a recording medium such as an HDD (Hard Disk Drive), a memory card, an optical Disk, or a magnetic tape.

With the configuration as shown in fig. 9, a compact and high-performance zoom lens imaging apparatus having a high zoom ratio can be realized.

In fig. 9, an example in which the zoom lens of the present invention is applied to a monitoring camera is shown. However, the zoom lens of the present invention can be applied not only to a monitoring camera but also to a video camera, a digital still camera, a single-lens reflex camera, a mirror-less single-lens reflex camera, and the like.

[ industrial applicability ]

As described above, the zoom lens of the present invention is useful for a small-sized imaging device equipped with a solid-state imaging element such as a CCD or a CMOS, and is particularly suitable for a monitoring camera which is required to have high optical performance.

Description of the drawings:

G₁: a 1 st lens group; g₂: a 2 nd lens group; g₃: a 3 rd lens group; g₄: a 4 th lens group; g₅: a 5 th lens group; g₆: a 6 th lens group; g_R: a subsequent lens group; l is₁₁，L₃₁，L₃₂，L₅₃: a biconcave negative lens; l is₂₁，L₃₄，L₄₂，L₅₅，L₅₇，L₆₁: a negative meniscus lens; l is₂₂，L₂₃，L₃₃，L₄₁，L₅₁，L₅₂，L₅₄，L₅₆，L₄₆₂: a biconvex positive lens; l is₆₂: a positive meniscus lens; STP: an aperture stop; CG: a cover glass; IMG: an image plane; 10: a zoom lens; 11: a lens barrel section; 20: a solid-state imaging element; 21: a camera body; 100: an image pickup device.

Claims

1. A zoom lens characterized in that a lens element is provided,

the zoom lens is composed of a 1 st lens group having negative refractive power, a 2 nd lens group having positive refractive power, a 3 rd lens group having negative refractive power, and subsequent lens groups arranged in this order from the object side,

the subsequent lens group is composed of a 4 th lens group having positive refractive power, a 5 th lens group having positive refractive power, and a 6 th lens group having positive refractive power, which are arranged in this order from the object side,

wherein zooming from a wide-angle end to a telephoto end is performed by moving at least the 2 nd lens group and the 3 rd lens group along an optical axis while keeping the 1 st lens group fixed with respect to an image plane at all times, thereby changing an interval between the respective lens groups on the optical axis,

the zoom lens satisfies the following conditional expression:

(1)3.5≦|F1/Fw|≦20.0

(2)0.7≦|F1/Ft|≦2.0

(3)1.9≦|F2/F3|≦5.0

2. Zoom lens according to claim 1,

the zoom lens satisfies the following conditional expression:

(4)3.0≦|β3t/β3w|≦9.0

where β 3t denotes a lateral magnification of the 3 rd lens group at the telephoto end, and β 3w denotes a lateral magnification of the 3 rd lens group at the wide-angle end.

3. Zoom lens according to claim 1,

at the time of zooming, any one of the 4 th lens group or the 5 th lens group moves along an optical axis, and a conditional expression shown below is satisfied:

(5)3.0≦|βpt/βpw|≦10.0

where β pt denotes a lateral magnification of the movable group in the subsequent lens group at the telephoto end, and β pw denotes a lateral magnification of the movable group in the subsequent lens group at the wide-angle end.

4. Zoom lens according to claim 1,

the 1 st lens group is composed of 1 lens.

5. An image pickup apparatus, comprising:

a variable focus lens as claimed in any one of claims 1 to 4, and

and a solid-state imaging element that converts an optical image formed by the zoom lens into an electric signal.