# Patent

## Title
Zoom lens and imaging apparatus

## Abstract

A zoom lens consists of, in order from an object side, a positive first lens group, a negative moving lens group, a first positive moving lens group, a second positive moving lens group, and a subsequent lens group including a stop. During zooming, the first lens group is not moved, and the negative moving lens group, the first positive moving lens group, and the second positive moving lens group are moved. The first positive moving lens group consists of a positive single lens and a cemented lens obtained by cementing a positive lens and a negative lens. The zoom lens satisfies a predetermined conditional expression.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2019-171643, filed on Sep. 20, 2019. The above application is hereby expressly incorporated by reference, in its entirety, into the present application.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The technology of the present disclosure relates to a zoom lens and an imaging apparatus.
2. Description of the Related Art
In the related art, a zoom lens consisting of a plurality of lens groups of which mutual intervals are changed during zooming has been suggested as a lens system usable in a broadcasting camera, a movie imaging camera, a digital camera, and the like.
For example, WO2017/170047A discloses a lens system substantially consisting of, in order from an object side to an image side, at least two moving lens groups that include a first lens group which has a positive refractive power and is fixed with respect to an image surface during zooming, and a second lens group which has a negative refractive power and is adjacent to the first lens group, and that are moved by changing an interval with an adjacent group during zooming, and a final lens group that is arranged closest to the image side and is fixed with respect to the image surface during zooming. JP2016-164629A discloses a lens system substantially consisting of, in order from an object side to an image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a positive refractive power, in which during zooming, the first lens group and the fifth lens group are fixed with respect to an image surface, and the second lens group, the third lens group, and the fourth lens group are moved by changing intervals therebetween.
SUMMARY OF THE INVENTION
One embodiment according to the technology of the present disclosure provides a zoom lens that achieves size reduction and a high magnification and has favorable optical characteristics while suppressing a change in aberration during zooming, and an imaging apparatus comprising the zoom lens.
A zoom lens according to one aspect of the technology of the present disclosure consists of, in order from an object side to an image side, a first lens group that has a positive refractive power and is fixed with respect to an image surface during zooming, a negative moving lens group that consists of one or two lens groups moved along an optical axis by changing an interval with an adjacent lens group during zooming, and has a negative refractive power as a whole at a wide angle end, a first positive moving lens group that has a positive refractive power and is moved along the optical axis during zooming, a second positive moving lens group that has a positive refractive power and is moved along the optical axis during zooming, and a subsequent lens group including a stop, in which all intervals between adjacent lens groups are changed during zooming, all lens groups included in the negative moving lens group are moved to the image side during zooming from the wide angle end to a telephoto end, the first positive moving lens group consists of a single lens that is a positive lens, and a cemented lens configured by cementing two lenses in which any one is a positive lens and the other is a negative lens, and in a state where an object at infinity is focused, in a case where a focal length of the first lens group is denoted by f1, a focal length of the negative moving lens group at the wide angle end is denoted by fNw, a focal length of the first positive moving lens group is denoted by fP1, and a focal length of the second positive moving lens group is denoted by fP2, Conditional Expressions (1) and (2) are satisfied.

−11.5<f1/fNw<−8.5  (1)

0.5<fP2/fP1<1  (2)

It is preferable that the zoom lens of the aspect further satisfies at least one of Conditional Expression (1-1) or (2-1).

−11<f1/fNw<−9.5  (1-1)

0.6<fP2/fP1<0.9  (2-1)

In a case where a d line-based Abbe number of the negative lens of the first positive moving lens group is denoted by νn, it is preferable to satisfy Conditional Expression (3) below, and it is more preferable to satisfy Conditional Expression (3-1) below.

20<νn<40  (3)

25<νn<37  (3-1)

In a case where a d line-based Abbe number of a positive lens of which the d line-based Abbe number is largest out of the positive lenses included in the first positive moving lens group is denoted by νp, and a partial dispersion ratio, between g line and F line, of the positive lens of which the d line-based Abbe number is largest out of the positive lenses included in the first positive moving lens group is denoted by Op, it is preferable to satisfy Conditional Expressions (4) and (5) below. In addition, after Conditional Expressions (4) and (5) below are satisfied, it is more preferable to satisfy at least one of Conditional Expression (4-1) or (5-1).

80<νp  (4)

0.66<θp+0.001625×νp<0.72  (5)

90<νp<105  (4-1)

0.67<θp+0.001625×νp<0.7  (5-1)

In a state where an object at infinity is focused, in a case where a focal length of the negative lens of the first positive moving lens group is denoted by fn, and the focal length of the first positive moving lens group is denoted by fP1, it is preferable to satisfy Conditional Expression (6) below, and it is more preferable to satisfy Conditional Expression (6-1) below.

−4<fn/fP1<−1  (6)

−3.5<fn/fP1<−1.2  (6-1)

In a configuration satisfying Conditional Expression (6) above, in a case where a refractive index of the negative lens of the first positive moving lens group with respect to d line is denoted by Ndn, it is preferable to satisfy Conditional Expression (7) below, and it is more preferable to satisfy Conditional Expression (7-1) below.

1.55<Ndn<1.77  (7)

1.57<Ndn<1.7  (7-1)

It is preferable that the second positive moving lens group at the telephoto end is positioned on the object side from the second positive moving lens group at the wide angle end, and in a state where an object at infinity is focused, an interval between the first positive moving lens group and the second positive moving lens group is largest on a wide angle side from a zoom position at which a lateral magnification of a combined lens group obtained by combining the first positive moving lens group and the second positive moving lens group is −1.
In a state where an object at infinity is focused, during zooming from the wide angle end to the telephoto end, it is preferable that a combined lens group obtained by combining the first positive moving lens group and the second positive moving lens group, and the negative moving lens group simultaneously pass through respective points at which lateral magnifications are −1.
The negative moving lens group may be configured to consist of one lens group having a negative refractive power. Alternatively, the negative moving lens group may be configured to consist of one lens group having a negative refractive power and one lens group having a positive refractive power in order from the object side to the image side.
It is preferable that the first lens group comprises at least one lens that is moved along the optical axis during focusing.
An imaging apparatus according to another aspect of the technology of the present disclosure comprises the zoom lens of the aspect of the present disclosure.
In the present specification, “consist of” or “consisting of” means that a lens that substantially does not have a refractive power, and optical elements such as a stop, a filter, and a cover glass other than a lens, mechanism parts such as a lens flange, a lens barrel, an imaging element, and a camera shake correction mechanism, and the like may be included besides illustrated constituents.
In the present specification, a “ ̃group having a positive refractive power” means that the entire group has a positive refractive power. Similarly, a “ ̃group having a negative refractive power” means that the entire group has a negative refractive power. A “lens having a positive refractive power” and a “positive lens” have the same meaning. A “lens having a negative refractive power” and a “negative lens” have the same meaning. A “ ̃lens group” is not limited to a configuration consisting of a plurality of lenses and may be configured to consist of only one lens. As “one lens group”, a lens group included in one section in a case where a lens group is divided into sections at intervals that are changed during zooming is set as one lens group.
A compound aspherical lens (a lens in which a spherical lens and a film of an aspherical shape formed on the spherical lens are configured as a single unit and function as one aspherical lens as a whole) is not regarded as a cemented lens and is handled as one lens. The sign of a refractive power and a surface shape related to a lens including an aspherical surface are considered in a paraxial region unless otherwise specified.
The “focal length” used in the conditional expressions is a paraxial focal length. The values used in the conditional expressions except the partial dispersion ratio are values in a case based on d line in a state where the object at infinity is focused. A partial dispersion ratio θgF of a certain lens between g line and F line is defined as θgF=(Ng−NF)/(NF−NC) in a case where the refractive indexes of the lens with respect to g line, F line, and C line are denoted by Ng, NF, and NC, respectively. In the present specification, “d line”, “C line”, “F line”, and “g line” are bright lines. The wavelength of d line is 587.56 nanometers (nm). The wavelength of C line is 656.27 nanometers (nm). The wavelength of F line is 486.13 nanometers (nm). The wavelength of g line is 435.84 nanometers (nm).



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram corresponding to a zoom lens of Example 1 of the present disclosure and illustrating a cross-sectional view of a configuration and a movement trajectory of a zoom lens according to one embodiment of the present disclosure.
FIG. 2 is a cross-sectional view illustrating a configuration of the zoom lens and luminous flux illustrated in FIG. 1.
FIG. 3 is each aberration diagram of the zoom lens of Example 1 of the present disclosure.
FIG. 4 is a diagram illustrating a cross-sectional view of a configuration and a movement trajectory of a zoom lens of Example 2 of the present disclosure.
FIG. 5 is each aberration diagram of the zoom lens of Example 2 of the present disclosure.
FIG. 6 is a diagram illustrating a cross-sectional view of a configuration and a movement trajectory of a zoom lens of Example 3 of the present disclosure.
FIG. 7 is a cross-sectional view illustrating the configuration and luminous flux of the zoom lens illustrated in FIG. 6.
FIG. 8 is each aberration diagram of the zoom lens of Example 3 of the present disclosure.
FIG. 9 is a diagram illustrating a cross-sectional view of a configuration and a movement trajectory of a zoom lens of Example 4 of the present disclosure.
FIG. 10 is each aberration diagram of the zoom lens of Example 4 of the present disclosure.
FIG. 11 is a diagram illustrating a cross-sectional view of a configuration and a movement trajectory of a zoom lens of Example 5 of the present disclosure.
FIG. 12 is each aberration diagram of the zoom lens of Example 5 of the present disclosure.
FIG. 13 is a schematic configuration diagram of an imaging apparatus according to one embodiment of the present disclosure.



DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, one example of an embodiment according to the technology of the present disclosure will be described with reference to the drawings. FIG. 1 illustrates a cross-sectional view of a configuration and a movement trajectory at a wide angle end of a zoom lens according to one embodiment of the present disclosure. FIG. 2 is a cross-sectional view illustrating the configuration of the zoom lens and luminous flux. Examples illustrated in FIG. 1 and FIG. 2 correspond to a zoom lens of Example 1 described later. In the cross-sectional views of FIG. 1 and FIG. 2, a state where an object at infinity is focused is illustrated. A left side is an object side, and a right side is an image side. In FIG. 2, a wide angle end state is illustrated in an upper part denoted by “WIDE”, a middle focal length state is illustrated in a middle part denoted by “MIDDLE”, and a telephoto end state is illustrated in a lower part denoted by “TELE”. The “middle” in the “middle focal length” does not necessarily mean a center point between the wide angle end and a telephoto end, and the middle focal length is between the wide angle end and the telephoto end. In FIG. 2, axial luminous flux wa and luminous flux wb of the maximum angle of view in the wide angle end state, axial luminous flux ma and luminous flux mb of the maximum angle of view in the middle focal length state, and axial luminous flux to and luminous flux tb of the maximum angle of view in the telephoto end state are illustrated as luminous flux. Hereinafter, the zoom lens according to one embodiment of the present disclosure will be described mainly with reference to FIG. 1.
In FIG. 1, an example in which an optical member PP in which an incidence surface and an emission surface are parallel is arranged between the zoom lens and an image surface Sim is illustrated by assuming application of the zoom lens to an imaging apparatus. The optical member PP is a member that is assumed to correspond to various filters, a cover glass, a prism, and the like. For example, the various filters include a low-pass filter, an infrared cut filter, and a filter cutting a specific wavelength range. The optical member PP is a member not having a refractive power, and the optical member PP can be configured not to be included.
The zoom lens consists of, in order from the object side to the image side along an optical axis Z, a first lens group G1 having a positive refractive power, a negative moving lens group GN, a first positive moving lens group GP1 having a positive refractive power, a second positive moving lens group GP2 having a positive refractive power, and a subsequent lens group GR including aperture stop St. The negative moving lens group GN consists of one or two lens groups that are moved along the optical axis Z by changing an interval with an adjacent lens group during zooming, and has a negative refractive power as a whole at the wide angle end. During zooming, the first lens group G1 is fixed with respect to the image surface Sim. The one or two lens groups constituting the negative moving lens group GN, the first positive moving lens group GP1, and the second positive moving lens group GP2 are moved along the optical axis Z, and all intervals between the adjacent lens groups are changed. By having the above configuration that includes at least five lens groups between which the intervals are changed during zooming, and in which a lens group having a positive refractive power is arranged closest to the object side, both a high magnification and reduction of a total length are easily achieved. In addition, since achromatization can be performed by the first positive moving lens group GP1 and the second positive moving lens group Gp2 having a positive refractive power, an advantage of suppressing a change in axial chromatic aberration on a telephoto side during zooming is achieved.
The zoom lens in the example illustrated in FIG. 1 consists of, in order from the object side to the image side, the first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In this example, the negative moving lens group GN consists of one lens group, and the second lens group G2 corresponds to the negative moving lens group GN. The third lens group G3 corresponds to the first positive moving lens group GP1. The fourth lens group G4 corresponds to the second positive moving lens group GP2. The fifth lens group G5 corresponds to the subsequent lens group GR. In this example, the subsequent lens group GR is fixed with respect to the image surface Sim during zooming. In FIG. 1, the movement trajectory of each lens group during zooming from the wide angle end to the telephoto end is schematically illustrated by a solid arrow below each of the second lens group G2, the third lens group G3, and the fourth lens group G4. In addition, in FIG. 1, the wide angle end and the telephoto end corresponding to the starting point and the ending point of the movement trajectory, respectively, are denoted by “WIDE” and “TELE”, respectively.
Each lens group in the example in FIG. 1 is composed of lenses described below. That is, the first lens group G1 consists of six lenses of lenses L11 to L16 in order from the object side to the image side. The second lens group G2 consists of seven lenses of lenses L21 to L27 in order from the object side to the image side. The third lens group G3 consists of three lenses of lenses L31 to L33 in order from the object side to the image side. The fourth lens group G4 consists of four lenses of lenses L41 to L44 in order from the object side to the image side. The fifth lens group G5 consists of an aperture stop St and 13 lenses of lenses L51 to L63 in order from the object side to the image side. The aperture stop St in FIG. 1 does not illustrate a shape and illustrates a position in an optical axis direction.
During zooming from the wide angle end to the telephoto end, all lens groups included in the negative moving lens group GN are configured to be moved to the image side. According to such a configuration, the negative moving lens group GN can bear a main zooming effect. Thus, an advantage of a high magnification is achieved.
The first positive moving lens group GP1 consists of a single lens that is a positive lens, and a cemented lens configured by cementing two lenses in which any one is a positive lens and the other is a negative lens. The cemented lens configured by cementing two lenses in which any one is a positive lens and the other is a negative lens may be obtained by cementing the positive lens and the negative lens in order from the object side or by cementing the negative lens and the positive lens in order from the object side. In the first positive moving lens group GP1, the single lens and the cemented lens may be arranged in order from the object side to the image side, or the cemented lens and the single lens may be arranged in order from the object side to the image side. By including the cemented lens in the first positive moving lens group GP1, a change in axial chromatic aberration during zooming can be favorably suppressed. In addition, by having the above configuration in which the first positive moving lens group GP1 consists of three lenses, a zoom stroke (movement range during zooming) can be secured by saving space compared to a configuration consisting of four or more lenses. Thus, both a high magnification and reduction of the total length are easily achieved.
In a state where the object at infinity is focused, in a case where the focal length of the first lens group G1 is denoted by f1 and the focal length of the negative moving lens group GN at the wide angle end is denoted by fNw, the zoom lens is configured to satisfy Conditional Expression (1) below. By satisfying Conditional Expression (1) not to be below the lower limit thereof, the refractive power of the first lens group G1 is not excessively decreased. Thus, the first lens group G1 can form an image point closer to the object side. Generally, the zoom stroke of the negative moving lens group GN is set to be within a range from the surface of the first lens group G1 closest to the image side to the image point formed by the first lens group G1. Thus, by satisfying Conditional Expression (1) not to be below the lower limit thereof, an increase in zoom stroke of the negative moving lens group GN can be suppressed. Accordingly, both a high magnification and size reduction are easily achieved. Alternatively, by satisfying Conditional Expression (1) not to be below the lower limit thereof, the refractive power of the negative moving lens group GN is not excessively increased. Thus, a change in aberration during zooming is easily suppressed. By satisfying Conditional Expression (1) not to be above the upper limit thereof, the refractive power of the first lens group G1 is not excessively increased. Thus, since the first lens group G1 can form the image point closer to the image side, the zoom stroke of the negative moving lens group GN is not excessively reduced. Accordingly, since rays can be smoothly curved, both a high magnification and high characteristics are easily achieved. Alternatively, by satisfying Conditional Expression (1) not to be above the upper limit thereof, the refractive power of the negative moving lens group GN is not excessively decreased. Thus, both a high magnification and size reduction are easily achieved. Furthermore, in a case where it is configured to satisfy Conditional Expression (1-1) below, more favorable characteristics can be achieved.

−11.5<f1/fNw<−8.5  (1)

−11<f1/fNw<−9.5  (1-1)

In a state where the object at infinity is focused, in a case where the focal length of the first positive moving lens group GP1 is denoted by fP1 and the focal length of the second positive moving lens group GP2 is denoted by fP2, the zoom lens is configured to satisfy Conditional Expression (2) below. By satisfying Conditional Expression (2) not to be below the lower limit thereof, the refractive power of the first positive moving lens group GP1 is not excessively decreased with respect to the second positive moving lens group GP2. Thus, the diameter of the lens of the second positive moving lens group GP2 is easily decreased, and an increase in zoom stroke of the first positive moving lens group GP1 can be suppressed. Accordingly, both a high magnification and size reduction are easily achieved. By satisfying Conditional Expression (2) not to be above the upper limit thereof, the refractive power of the first positive moving lens group GP1 is not excessively increased with respect to the second positive moving lens group GP2. Thus, since a change in aberration during zooming is easily suppressed, both a high magnification and high characteristics are easily achieved. Furthermore, in a case where it is configured to satisfy Conditional Expression (2-1) below, more favorable characteristics can be achieved.

0.5<fP2/fP1<1  (2)

0.6<fP2/fP1<0.9  (2-1)

Like the zoom lens according to the embodiment of the present disclosure, in a lens system of a type consisting of, in order from the object side to the image side, the first lens group G1 having a positive refractive power, three or more moving lens groups that are moved by changing intervals between adjacent lens groups during zooming, and the subsequent lens group GR including the aperture stop St, appropriate refractive power arrangement of the moving lens groups is important for achieving both size reduction and a high magnification. In a case where a high magnification is achieved, a change in axial chromatic aberration during zooming is likely to be increased. Thus, it is important to set a configuration for correcting chromatic aberration of the moving lens groups. By having the above group configuration and satisfying Conditional Expressions (1) and (2), the zoom lens according to the embodiment of the technology of the present disclosure achieves size reduction, a high magnification, and high characteristics and easily suppresses a change in aberration during zooming.
Furthermore, in a case where the d line-based Abbe number of the negative lens of the first positive moving lens group GP1 is denoted by νn, it is preferable to satisfy Conditional Expression (3) below in order to suppress the chromatic aberration. By satisfying Conditional Expression (3) not to be below the lower limit thereof, excessive correction of the axial chromatic aberration is suppressed, and a change in chromatic aberration during zooming is easily favorably suppressed. By satisfying Conditional Expression (3) not to be above the upper limit thereof, insufficient correction of the axial chromatic aberration is suppressed, and a change in chromatic aberration during zooming is easily favorably suppressed. Furthermore, in a case where it is configured to satisfy Conditional Expression (3-1) below, more favorable characteristics can be achieved.

20<νn<40  (3)

25<νn<37  (3-1)

In a case where the d line-based Abbe number of the positive lens having the highest d line-based Abbe number of the positive lenses included in the first positive moving lens group GP1 is denoted by νp, it is preferable to satisfy Conditional Expression (4) below. By satisfying Conditional Expression (4) not to be below the lower limit thereof, insufficient correction of the axial chromatic aberration is suppressed, and a change in chromatic aberration during zooming is easily favorably suppressed. Furthermore, it is more preferable that the zoom lens satisfies Conditional Expression (4-1) below. By satisfying Conditional Expression (4-1) not to be below the lower limit thereof, insufficient correction of the axial chromatic aberration is more favorably suppressed, and a change in chromatic aberration during zooming is easily favorably suppressed. By satisfying Conditional Expression (4-1) not to be above the upper limit thereof, excessive correction of the axial chromatic aberration is suppressed, and a change in chromatic aberration during zooming is easily favorably suppressed.

80<νp  (4)

90<νp<105  (4-1)

In a case where the d line-based Abbe number of the positive lens having the highest d line-based Abbe number of the positive lenses included in the first positive moving lens group GP1 is denoted by νp and the partial dispersion ratio, between g line and F line, of the positive lens having the highest d line-based Abbe number of the positive lenses included in the first positive moving lens group GP1 is denoted by Op, it is preferable to satisfy Conditional Expression (5) below. By satisfying Conditional Expression (5), second-order axial chromatic aberration is easily favorably corrected over the entire zoom range. Furthermore, in a case where it is configured to satisfy Conditional Expression (5-1) below, more favorable characteristics can be achieved.

0.66<θp+0.001625×νp<0.72  (5)

0.67<θp+0.001625×νp<0.7  (5-1)

It is preferable to satisfy Conditional Expressions (4) and (5) for favorable correction of the chromatic aberration. Furthermore, after Conditional Expressions (4) and (5) are satisfied, it is more preferable to satisfy at least one of Conditional Expression (4-1) or (5-1).
In a state where the object at infinity is focused, in a case where the focal length of the negative lens of the first positive moving lens group GP1 is denoted by fn and the focal length of the first positive moving lens group GP1 is denoted by fP1, it is preferable that the zoom lens satisfies Conditional Expression (6) below. By satisfying Conditional Expression (6) not to be below the lower limit thereof, the refractive power of the negative lens of the first positive moving lens group GP1 is not excessively decreased. Thus, insufficient correction of the axial chromatic aberration is suppressed, and a change in chromatic aberration during zooming is easily favorably suppressed. By satisfying Conditional Expression (6) not to be above the upper limit thereof, the refractive power of the negative lens of the first positive moving lens group GP1 is not excessively increased. Thus, excessive correction of the axial chromatic aberration is suppressed, and a change in chromatic aberration during zooming is easily favorably suppressed. Furthermore, in a case where it is configured to satisfy Conditional Expression (6-1) below, more favorable characteristics can be achieved.

−4<fn/fP1<−1  (6)

−3.5<fn/fP1<−1.2  (6-1)

In a configuration satisfying Conditional Expression (6), in a case where the refractive index of the negative lens of the first positive moving lens group GP1 with respect to d line is denoted by Ndn, it is preferable to satisfy Conditional Expression (7) below. By satisfying Conditional Expression (7) not to be below the lower limit thereof, a tendency for an excessive field curvature can be suppressed. Thus, a refractive power distribution for the negative lens of the first positive moving lens group GP1 for achieving both the configuration satisfying Conditional Expression (6) and favorable correction of the field curvature can be suitably set. By satisfying Conditional Expression (7) not to be above the upper limit thereof, a tendency for a positive Petzval sum can be suppressed. Thus, the refractive power distribution for the negative lens of the first positive moving lens group GP1 for achieving both the configuration satisfying Conditional Expression (6) and favorable correction of the field curvature can be suitably set. Furthermore, in a case where it is configured to satisfy Conditional Expression (7-1) below, more favorable characteristics can be achieved.

1.55<Ndn<1.77  (7)

1.57<Ndn<1.7  (7-1)

During zooming from the wide angle end to the telephoto end in a state where the object at infinity is focused, it is preferable that a combined lens group obtained by combining the first positive moving lens group GP1 and the second positive moving lens group GP2, and the negative moving lens group GN simultaneously pass through respective points at which lateral magnifications are −1. In such a case, a high magnification is easily achieved. In the drawing of the movement trajectory in FIG. 1, a zoom position at which the lateral magnification of the combined lens group and the lateral magnification of the negative moving lens group GN are −1 is indicated by “β=−1”.
It is preferable that the second positive moving lens group GP2 at the telephoto end is positioned on the object side from the second positive moving lens group GP2 at the wide angle end. Furthermore, in a state where the object at infinity is focused, it is preferable to configure that the interval between the first positive moving lens group GP1 and the second positive moving lens group GP2 is largest on the wide angle side from the zoom position at which the lateral magnification of the combined lens group obtained by combining the first positive moving lens group GP1 and the second positive moving lens group GP2 is −1. In the drawing of the movement trajectory in FIG. 1, a zoom position at which the interval between the first positive moving lens group GP1 and the second positive moving lens group GP2 is largest is denoted by “Dmax”. In the lens system such as the zoom lens according to the embodiment of the present disclosure, the amount of outer edge rays of non-axial luminous flux is largest on the wide angle side from the zoom position at which the lateral magnification of the combined lens group is −1. A state where the interval between the first positive moving lens group GP1 and the second positive moving lens group GP2 is largest is a state where the first positive moving lens group GP1 is extended to the object side. By having the configuration in which the interval between the first positive moving lens group GP1 and the second positive moving lens group GP2 is largest within a zoom range between the wide angle end and the zoom position at which the lateral magnification of the combined lens group is −1, the first positive moving lens group GP1 having a positive refractive power can be extended to the object side at or near the zoom position at which the amount of outer edge rays of the non-axial luminous flux is largest. Accordingly, since the outer edge rays of the non-axial luminous flux in the first lens group G1 can be further reduced, an increase in diameter of the first lens group G1 can be suppressed, and an advantage of size reduction is achieved.
A focusing operation may be configured to be performed by moving at least one lens of the first lens group G1 along the optical axis Z. In a case where the first lens group G1 comprises a lens group (hereinafter, referred to as the focus lens group) that is moved during focusing, the advancing amount of the focus lens group during focusing at the telephoto end can be suppressed. Thus, the minimum subject distance can be decreased. In addition, since the advancing amount of the focus lens group during focusing can be constant over the entire zoom range, a mechanism can be simplified.
The first lens group G1 in the example in FIG. 1 comprises two focus lens groups. More specifically, the first lens group G1 in the example in FIG. 1 consists of, in order from the object side to the image side, a first a lens group G1a that is fixed with respect to the image surface Sim during focusing, a first b lens group G1b that is moved along the optical axis Z during focusing, and the first c lens group G1c that is moved along the optical axis Z by changing a mutual interval with the first b lens group G1b during focusing. A horizontal bidirectional arrow shown below each of the first b lens group G1b and the first c lens group G1c in FIG. 1 indicates that each of the first b lens group G1b and the first c lens group G1c is the focus lens group.
The example illustrated in FIG. 1 is one example and can be subjected to various modifications. For example, the number of lenses constituting each lens group other than the first positive moving lens group GP1 can be a number different from the example illustrated in FIG. 1.
While the negative moving lens group GN in the example in FIG. 1 consists of one lens group, the negative moving lens group GN may be configured to consist of two lens groups between which a mutual interval is changed during zooming. In a case where the negative moving lens group GN consists of one lens group having a negative refractive power, a structure related to moving groups can be further simplified. Thus, an advantage of reducing overall manufacturing error and reducing the cost of components is achieved. In a case where the negative moving lens group GN consists of, in order from the object side to the image side, one lens group having a negative refractive power and one lens group having a positive refractive power, a change in aberration during zooming is easily suppressed.
While the subsequent lens group GR in the example in FIG. 1 is fixed with respect to the image surface during zooming, the subsequent lens group GR may be configured to be moved during zooming. In the configuration in which the subsequent lens group GR is fixed with respect to the image surface during zooming, the distance from the lens surface closest to the object side to the lens surface closest to the image side is not changed during zooming, and a change in centroid of the lens system can be reduced. Thus, convenience of use during imaging can be increased. In the configuration in which the subsequent lens group GR is moved during zooming, an advantage of suppressing a change in aberration during zooming is achieved.
The above preferred configurations and available configurations can be randomly combined and preferably, are appropriately selectively employed depending on required specifications. According to the technology of the present disclosure, a zoom lens that achieves size reduction and a high magnification and has favorable optical characteristics while suppressing a change in aberration during zooming can be implemented. The “high magnification” here means that a zoom magnification is greater than or equal to a power of 100.
Next, examples of the numerical value of the zoom lens according to the embodiment of the present disclosure will be described.
Example 1
A configuration and a movement trajectory of the zoom lens of Example 1 are illustrated in FIG. 1, and the illustration method and the configuration thereof are described above. Thus, a duplicate description will be partially omitted here. The zoom lens of Example 1 consists of, in order from the object side to the image side, the first lens group G1 having a positive refractive power, the second lens group G2 having a negative refractive power, the third lens group G3 having a positive refractive power, the fourth lens group G4 having a positive refractive power, and the fifth lens group G5 having a positive refractive power. During zooming, the first lens group G1 and the fifth lens group G5 are fixed with respect to the image surface Sim, and the second lens group G2, the third lens group G3, and the fourth lens group G4 are moved along the optical axis Z by changing the intervals between the adjacent lens groups. The second lens group G2 corresponds to the negative moving lens group GN. The third lens group G3 corresponds to the first positive moving lens group GP1. The fourth lens group G4 corresponds to the second positive moving lens group GP2. The fifth lens group G5 corresponds to the subsequent lens group GR. The first lens group G1 consists of the first a lens group G1a, the first b lens group G1b, and the first c lens group G1c in order from the object side to the image side. During focusing from the object at infinity to an object in a short range, the first b lens group G1b and the first c lens group G1c are moved to the object side by changing a mutual interval, and all of the other lens groups are fixed with respect to the image surface Sim. The first a lens group G1a consists of three lenses of the lenses L11 to L13 in order from the object side to the image side. The first b lens group G1b consists of two lenses of the lenses L14 and L15 in order from the object side to the image side. The first c lens group G1c consists of one lens of the lens L16. The second lens group G2 consists of seven lenses of the lenses L21 to L27 in order from the object side to the image side. The third lens group G3 consists of three lenses of the lenses L31 to L33 in order from the object side to the image side. The fourth lens group G4 consists of four lenses of the lenses L41 to L44 in order from the object side to the image side. The fifth lens group G5 consists of the aperture stop St and 13 lenses of the lenses L51 to L63 in order from the object side to the image side. Above is the summary of the zoom lens of Example 1.
For the zoom lens of Example 1, fundamental lens data is shown in Table 1A and Table B, specifications and variable surface intervals are shown in Table 2, and aspherical coefficients are shown in Table 3. The fundamental lens data is separately displayed in two tables of Table 1A and Table 1B in order to avoid one long table. Table 1A shows the first lens group G1 to the fourth lens group G4, and Table 1B shows the fifth lens group G5 and the optical member PP. Table 1A, Table 1B, and Table 2 show data in a state where the object at infinity is focused.
In Table 1A and Table 1B, the field of Sn shows a surface number in a case where the surface closest to the object side is set as a first surface and the number is increased by one at a time toward the image side. The field of R shows the radius of curvature of each surface. The field of D shows a surface interval on the optical axis between each surface and a surface adjacent thereto on the image side. The field of Nd shows the refractive index of each constituent with respect to d line. The field of νd shows the d line-based Abbe number of each constituent. The field of θgF shows the partial dispersion ratio of each constituent between g line and F line.
In Table 1A and Table 1B, the sign of the radius of curvature of a surface having a shape of a convex surface toward the object side is positive, and the sign of the radius of curvature of a surface having a shape of a convex surface toward the image side is negative. In Table 1B, the aperture stop St and the optical member PP are also shown together. In Table 1B, the surface number and a word (St) are written in the field of the surface number of the surface corresponding to the aperture stop St. In Table 1A and Table 1B, a symbol DD[ ] is used for the variable surface interval during zooming. The variable surface interval is shown in the field of D by adding the surface number on the object side of the interval in [ ].
Table 2 shows a zoom magnification Zr, a focal length f, a back focus Bf converted to a distance in air, an F number FNo., a maximum total angle of view 2ω, and the variable surface interval during zooming based on d line. In the field of 2ω, (°) means that the unit is degree. In Table 2, values in the wide angle end state, the middle focal length state, and the telephoto end state are shown in the fields marked with WIDE, MIDDLE, and TELE, respectively.
In the fundamental lens data, the surface number of an aspherical surface is marked with *, and the numerical value of a paraxial radius of curvature is written in the field of the radius of curvature of the aspherical surface. In Table 3, the field of Sn shows the surface number of the aspherical surface, and the fields of KA and Am (m=3, 4, 5, . . . 16) show the numerical value of the aspherical coefficient for each aspherical surface. In the numerical value of the aspherical coefficient in Table 3, “E±n” (n: integer) means “×10±n”. KA and Am are aspherical coefficients in an aspherical expression represented by the following expression.

Zd=C×h2/{1+(1−KA×C2×h2)1/2}+ΣAm×hm 

where
Zd: aspherical depth (length of a perpendicular line drawn from a point on the aspherical surface having a height h to a plane that is in contact with an aspherical vertex and is perpendicular to the optical axis)
h: height (distance from the optical axis to the lens surface)
C: reciprocal of paraxial radius of curvature
KA and Am: aspherical coefficients
In the aspherical expression, Σ means the total sum related to m.
In the data of each table, degree is used as the unit of angle, and mm (millimeter) is used as the unit of length. However, since the optical system can be used even in a case where propositional enlargement or propositional reduction is performed, other appropriate units can also be used. In addition, numerical values that are rounded to a predetermined number of digits are written in each table shown below.







TABLE 1A







Example 1












Sn
R
D
Nd
νd
θgF















 1
−1314.44736
4.400
1.83481
42.73
0.56481


 2
375.22212
2.000





 3
380.98802
24.220
1.43387
95.18
0.53733


 4
−619.18405
0.120





 5
584.09992
13.630
1.43387
95.18
0.53733


 6
−1937.22858
21.520





 7
396.43760
17.340
1.43387
95.18
0.53733


 8
−2314.51657
0.120





 9
295.16013
19.200
1.43700
95.10
0.53364


10
∞
2.160





11
172.64422
16.940
1.43700
95.10
0.53364


12
358.69766
DD[12]





*13 
935.98696
1.800
1.90366
31.31
0.59481


14
50.73223
6.010





15
−135.10191
1.800
1.87070
40.73
0.56825


16
40.80800
4.960
1.43700
95.10
0.53364


17
150.59356
4.690





18
−53.04330
1.800
1.89800
34.00
0.58703


19
136.79400
4.720
1.89286
20.36
0.63944


20
−96.87418
0.140





21
440.21414
9.390
1.80518
25.45
0.61571


22
−34.56000
1.820
1.80400
46.53
0.55775


23
−572.90804
DD[23]





24
246.87583
11.640
1.49700
81.54
0.53748


*25 
−123.60927
0.120





26
416.68258
10.110
1.43700
95.10
0.53364


27
−127.84400
2.520
1.59270
35.27
0.59363


28
−1862.36878
DD[28]





29
120.01989
12.810
1.43700
95.10
0.53364


30
−225.91503
0.120





*31 
239.27475
6.170
1.43700
95.10
0.53364


32
−432.65553
0.230





33
884.55488
2.410
1.85883
30.00
0.59793


34
162.55600
9.050
1.43700
95.10
0.53364


35
−316.46190
DD[35]



















TABLE 1B







Example 1












Sn
R
D
Nd
νd
θgF















36 (St)
∞
5.740





37
−109.60235
1.300
1.80100
34.97
0.58642


38
82.29280
0.120





39
49.51289
4.610
1.84666
23.78
0.61923


40
354.30763
0.860





41
−531.15341
1.300
1.64000
60.08
0.53704


42
82.11128
9.770





43
−446.16003
2.450
1.80100
34.97
0.58642


44
49.37100
16.950
1.80518
25.43
0.61027


45
−59.80055
1.650





46
−37.24000
1.800
1.77250
49.60
0.55212


47
37.24000
8.700
1.53172
48.84
0.56309


48
−74.93557
0.120





49
−195.94504
3.160
1.56732
42.82
0.57309


50
−78.43840
8.510





51
−59.29837
4.280
1.54814
45.78
0.56859


52
−33.89154
0.580





53
−925.12829
9.190
2.00069
25.46
0.61364


54
53.62076
1.220





55
40.81294
11.260
1.53172
48.84
0.56309


56
−40.81294
0.120





57
78.01863
7.680
1.59551
39.24
0.58043


58
−30.20900
2.100
2.00069
25.46
0.61364


59
−150.40026
0.250





60
∞
1.000
1.51633
64.14
0.53531


61
∞
11.372





62
∞
33.000
1.60859
46.44
0.56664


63
∞
13.200
1.51633
64.05
0.53463


64
∞
5.510
















TABLE 2







Example 1













WIDE
MIDDLE
TELE
















Zr
1.0
21.6
120.6



f
8.291
179.225
1000.085



Bf
47.012
47.012
47.012



FNo.
1.76
1.76
5.17



2ω (°)
69.8
3.4
0.6



DD[12]
2.723
160.691
179.393



DD[23]
295.478
79.686
2.937



DD[28]
2.496
12.006
4.223



DD[35]
2.318
50.632
116.462

















TABLE 3







Example 1










Sn
13
25
31





KA
 1.0000000E+00
 1.0000000E+00
 1.0000000E+00


A3 
 3.3484999E−07
 1.4341034E−09
−2.4837372E−09


A4 
 3.4708539E−07
 1.0726671E−07
−2.3796633E−07


A5 
 1.7815640E−07
−5.4598300E−09
−1.1625905E−08


A6 
−4.5054058E−08
 4.5446725E−10
 1.0618218E−09


A7 
 6.7040497E−09
−1.1808220E−11
−3.9021456E−11


A8 
−5.9737791E−10
 7.9933403E−14
 3.6579030E−13


A9 
 3.4501013E−11
−9.1511307E−15
 2.2388337E−15


A10
−1.7034215E−12
 3.7107919E−16
 2.8939265E−16


A11
 9.6957627E−14
 5.5308506E−18
−5.6245445E−18


A12
−4.4624137E−15
−2.9574739E−19
−1.6931128E−19


A13
 8.3632689E−17
−2.3635232E−21
 2.2430720E−21


A14
 2.0291266E−18
 1.2147121E−22
 5.3204136E−23


A15
−1.1813140E−19
 3.7765063E−25
−3.5010780E−25


A16
 1.5090915E−21
−1.9548099E−26
−6.9906878E−27









FIG. 3 illustrates each aberration diagram of the zoom lens of Example 1 in a state where the object at infinity is focused. In FIG. 3, in order from the left, spherical aberration, astigmatism, distortion, and lateral chromatic aberration are illustrated. In FIG. 3, aberration in the wide angle end state is illustrated in an upper part denoted by “WIDE”, aberration in the middle focal length state is illustrated in a middle part denoted by “MIDDLE”, and aberration in the telephoto end state is illustrated in a lower part denoted by “TELE”. In the spherical aberration diagram, a solid line, a long broken line, a short broken line, and a one-dot chain line illustrate aberration on d line, C line, F line, and g line, respectively. In the astigmatism diagram, a solid line illustrates aberration on d line in a sagittal direction, and a short broken line illustrates aberration on d line in a tangential direction. In the distortion diagram, a solid line illustrates aberration on d line. In the lateral chromatic aberration diagram, a long broken line, a short broken line, and a one-dot chain line illustrate aberration on C line, F line, and g line, respectively. In the spherical aberration diagram, FNo. means the F number. In other aberration diagrams, ω means a half angle of view.
Symbols, meanings, writing methods, and illustration methods of each data related to Example 1 are the same in the following examples unless otherwise specified. Thus, duplicate descriptions will be omitted below.
Example 2
A configuration and a movement trajectory of a zoom lens of Example 2 are illustrated in FIG. 4. The zoom lens of Example 2 has the same configuration as the summary of the zoom lens of Example 1. For the zoom lens of Example 2, fundamental lens data is shown in Table 4A and Table 4B, specifications and variable surface intervals are shown in Table 5, aspherical coefficients are shown in Table 6, and each aberration diagram is illustrated in FIG. 5.







TABLE 4A







Example 2












Sn
R
D
Nd
νd
θgF















 1
−19979.28502
4.400
1.83400
37.18
0.57780


 2
376.22459
2.000





 3
375.57742
19.637
1.43387
95.18
0.53733


 4
−1160.19070
0.120





 5
879.73786
9.026
1.43875
94.94
0.53433


 6
−2434.06960
27.405





 7
387.35889
16.262
1.43387
95.18
0.53733


 8
−2461.01247
0.120





 9
272.85762
16.896
1.43875
94.94
0.53433


10
1978.11923
1.818





11
180.85657
15.189
1.43875
94.94
0.53433


12
409.89905
DD[12]





*13 
−639.76370
2.500
1.90619
35.82
0.58145


14
45.26125
6.183





15
−142.20901
1.500
1.90620
37.36
0.57707


16
76.84764
4.882





17
−82.50966
1.500
1.80816
40.43
0.57160


18
103.88060
4.664
1.80809
22.76
0.63073


19
−138.87892
0.120





20
116.72867
10.770
1.82942
21.81
0.63515


21
−34.42516
1.500
1.95000
33.09
0.58805


22
205.16333
4.020
1.59410
60.47
0.55516


23
−310.87009
DD[23]





24
242.73790
10.808
1.43700
95.10
0.53364


*25 
−124.85625
0.120





26
577.42024
5.200
1.43700
95.10
0.53364


27
−349.07637
2.020
1.59270
35.31
0.59336


28
4300.17985
DD[28]





29
100.65446
12.865
1.43700
95.10
0.53364


30
−597.77109
0.128





*31 
369.66649
4.891
1.43700
95.10
0.53364


32
−549.97043
0.120





33
246.23624
2.000
1.87448
33.15
0.58972


34
90.41705
14.400
1.43700
95.10
0.53364


35
−164.83600
DD[35]



















TABLE 4B







Example 2












Sn
R
D
Nd
νd
θgF















36 (St)
∞
5.456





37
−123.75668
2.161
1.74287
53.71
0.54425


38
105.16403
0.120





39
42.81302
6.066
1.83102
23.45
0.62254


40
79.05565
4.825





41
−2672.64903
2.500
1.72047
55.48
0.54271


42
81.92592
11.384





43
−445.30361
1.500
1.85118
34.46
0.58651


44
28.49834
7.274
1.72396
31.95
0.59787


45
−133.13767
2.162





46
−59.55084
1.500
1.82765
46.46
0.55725


47
45.47260
7.368
1.56016
51.59
0.55655


48
−60.98734
0.120





49
118.49330
8.036
1.88994
20.50
0.62923


50
3965.21386
11.953





51
251.77149
6.665
1.64146
59.43
0.54234


52
−52.65705
0.120





53
−1081.71282
3.902
1.93599
34.40
0.58469


54
39.52121
0.120





55
38.73223
12.587
1.45836
84.89
0.50545


56
−112.80653
0.120





57
67.42095
5.510
1.74390
30.16
0.59875


58
−63.26034
1.800
1.97261
16.53
0.66663


59
−257.08876
0.250





60
∞
1.000
1.51633
64.14
0.53531


61
∞
11.815





62
∞
33.000
1.60863
46.60
0.56787


63
∞
13.200
1.51633
64.05
0.53463


64
∞
5.511
















TABLE 5







Example 2













WIDE
MIDDLE
TELE
















Zr
1.0
28.0
120.6



f
8.273
231.631
997.667



Bf
47.455
47.455
47.455



FNo.
1.76
1.80
5.18



2ω (°)
70.4
2.6
0.6



DD[12]
3.009
172.366
186.410



DD[23]
300.438
69.456
2.844



DD[28]
12.454
15.582
2.987



DD[35]
2.247
60.744
125.906

















TABLE 6







Example 2










Sn
13
25
31





KA
 1.0000000E+00
 1.0000000E+00
 1.0000000E+00


A3 
 0.0000000E+00
 0.0000000E+00
 0.0000000E+00


A4 
 6.3438393E−07
 2.0128702E−07
−2.9550844E−07


A5 
 7.6791228E−08
−9.8169288E−09
 1.3826476E−08


A6 
−7.7309931E−09
 1.5316378E−09
−1.6688302E−09


A7 
−3.1643996E−10
−1.7021879E−10
 1.3398339E−11


A8 
 1.5912916E−10
 8.4370119E−12
 5.7440881E−12


A9 
−1.7172261E−11
−9.8454833E−14
−2.5059424E−13


A10
 7.0064058E−13
−4.3453113E−15
−9.5003421E−16


A11
 1.8606267E−14
 5.5846966E−17
 2.3332275E−16


A12
−2.8394809E−15
 3.5313772E−19
−1.0776179E−18


A13
 6.5234868E−17
 2.7502736E−19
−1.8494947E−19


A14
 2.5807864E−18
−1.4230041E−20
 4.5998255E−21


A15
−1.4672685E−19
 2.5927640E−22
−3.8123231E−23


A16
 1.9648262E−21
−1.6718312E−24
 6.8746386E−26









Example 3
For a zoom lens of Example 3, a configuration and a movement trajectory are illustrated in FIG. 6, and the configuration and luminous flux are illustrated in FIG. 7. The zoom lens of Example 3 consists of, in order from the object side to the image side, the first lens group G1 having a positive refractive power, the second lens group G2 having a negative refractive power, the third lens group G3 having a positive refractive power, the fourth lens group G4 having a positive refractive power, the fifth lens group G5 having a positive refractive power, and a sixth lens group G6 having a positive refractive power. During zooming, the first lens group G1 and the sixth lens group G6 are fixed with respect to the image surface Sim, and the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 are moved along the optical axis Z by changing intervals between adjacent lens groups. In FIG. 6, the movement trajectory of each lens group during zooming from the wide angle end to the telephoto end is schematically illustrated by a solid arrow below each of the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5. In the zoom lens of Example 3, the negative moving lens group GN consists of two lens groups. The second lens group G2 and the third lens group G3 correspond to the negative moving lens group GN. The fourth lens group G4 corresponds to the first positive moving lens group GP1. The fifth lens group G5 corresponds to the second positive moving lens group GP2. The sixth lens group G6 corresponds to the subsequent lens group GR. The first lens group G1 consists of the first a lens group G1a, the first b lens group G1b, and the first c lens group G1c in order from the object side to the image side. During focusing from the object at infinity to an object in a short range, the first b lens group G1b and the first c lens group G1c are moved to the object side by changing a mutual interval, and all of the other lens groups are fixed with respect to the image surface Sim. The first a lens group G1a consists of three lenses of the lenses L11 to L13 in order from the object side to the image side. The first b lens group G1b consists of two lenses of the lenses L14 and L15 in order from the object side to the image side. The first c lens group G1c consists of one lens of the lens L16. The second lens group G2 consists of four lenses of the lenses L21 to L24 in order from the object side to the image side. The third lens group G3 consists of three lenses of the lenses L31 to L33 in order from the object side to the image side. The fourth lens group G4 consists of three lenses of the lenses L41 to L43 in order from the object side to the image side. The fifth lens group G5 consists of four lenses of the lenses L51 to L54 in order from the object side to the image side. The sixth lens group G6 consists of the aperture stop St and 13 lenses of lenses L61 to L73 in order from the object side to the image side. Above is the summary of the zoom lens of Example 3.
For the zoom lens of Example 3, fundamental lens data is shown in Table 7A and Table 7B, specifications and variable surface intervals are shown in Table 8, aspherical coefficients are shown in Table 9, and each aberration diagram is illustrated in FIG. 8.







TABLE 7A







Example 3












Sn
R
D
Nd
νd
θgF















1 
−20835.65169
4.400
1.83400
37.18
0.57780


2 
376.28625
2.000





3 
375.62687
18.807
1.43387
95.18
0.53733


4 
−1156.15289
0.120





5 
877.21908
8.612
1.43875
94.94
0.53433


6 
−2415.89549
27.219





7 
386.96457
15.914
1.43387
95.18
0.53733


8 
−2465.67317
0.120





9 
272.46329
15.981
1.43875
94.94
0.53433


10
1977.04637
1.501





11
180.39654
15.189
1.43875
94.94
0.53433


12
409.84553
DD[12]





*13 
−638.19838
2.500
1.90619
35.98
0.58100


14
45.23044
6.183





15
−141.97026
1.500
1.90620
37.74
0.57602


16
76.79880
4.438





17
−82.42478
1.500
1.80868
40.43
0.57157


18
111.64068
4.663
1.80756
22.78
0.63062


19
−139.16530
DD[19]





20
116.84688
10.770
1.82934
21.81
0.63514


21
−34.50935
1.500
1.95000
33.09
0.58804


22
204.52983
4.020
1.59410
60.47
0.55516


23
−312.66000
DD[23]





24
243.04852
10.244
1.43700
95.10
0.53364


*25 
−124.89150
0.120





26
580.96783
5.200
1.43700
95.10
0.53364


27
−345.07965
2.020
1.59270
35.31
0.59336


28
4155.82719
DD[28]





29
100.64936
12.979
1.43700
95.10
0.53364


30
−598.44413
0.201





*31 
368.80746
4.859
1.43700
95.10
0.53364


32
−554.61142
0.120





33
246.78912
2.000
1.87573
33.07
0.58993


34
90.30287
14.369
1.43700
95.10
0.53364


35
−165.06917
DD[35]



















TABLE 7B







Example 3












Sn
R
D
Nd
νd
θgF















36 (St)
∞
5.443





37
−123.66864
2.152
1.74013
53.99
0.54392


38
106.23972
0.120





39
43.07978
6.038
1.82873
23.56
0.62166


40
79.41060
4.793





41
−2045.29618
2.417
1.71427
55.75
0.54278


42
81.84372
11.272





43
−450.84998
1.500
1.85111
33.90
0.58814


44
28.54578
7.398
1.72407
31.81
0.59828


45
−132.79641
2.089





46
−59.56628
1.522
1.82755
46.41
0.55735


47
45.48327
7.378
1.56028
51.74
0.55624


48
−60.94569
0.120





49
118.37886
8.225
1.89083
20.46
0.62941


50
4081.97394
12.053





51
251.30507
6.682
1.64159
59.42
0.54234


52
−52.64719
0.120





53
−1086.74320
3.764
1.93580
34.41
0.58467


54
39.52357
0.120





55
38.73128
12.447
1.45850
86.38
0.50346


56
−112.66691
0.120





57
67.33817
5.510
1.74408
29.70
0.59983


58
−63.27986
1.811
1.97235
16.86
0.66452


59
−256.78118
0.250





60
∞
1.000
1.51633
64.14
0.53531


61
∞
11.915





62
∞
33.000
1.60863
46.60
0.56787


63
∞
13.200
1.51633
64.05
0.53463


64
∞
5.509
















TABLE 8







Example 3













WIDE
MIDDLE
TELE
















Zr
1.0
28.0
125.2



f
8.120
227.365
1016.564



Bf
47.553
47.553
47.553



FNo.
1.76
1.77
5.29



2ω (°)
71.8
2.8
0.6



DD[12]
2.341
172.008
186.290



DD[19]
0.961
1.161
0.962



DD[23]
301.106
69.423
1.323



DD[28]
12.765
15.893
2.270



DD[35]
2.051
60.739
128.378

















TABLE 9







Example 3










Sn
13
25
31





KA
 1.0000000E+00
 1.0000000E+00
 1.0000000E+00


A3 
 0.0000000E+00
 0.0000000E+00
 0.0000000E+00


A4 
 6.3438393E−07
 2.0128702E−07
−2.9550844E−07


A5 
 7.6791228E−08
−9.8169288E−09
 1.3826476E−08


A6 
−7.7309931E−09
 1.5316378E−09
−1.6688302E−09


A7 
−3.1643996E−10
−1.7021879E−10
 1.3398339E−11


A8 
 1.5912916E−10
 8.4370119E−12
 5.7440881E−12


A9 
−1.7172261E−11
−9.8454833E−14
−2.5059424E−13


A10
 7.0064058E−13
−4.3453113E−15
−9.5003421E−16


A11
 1.8606267E−14
 5.5846966E−17
 2.3332275E−16


A12
−2.8394809E−15
 3.5313772E−19
−1.0776179E−18


A13
 6.5234868E−17
 2.7502736E−19
−1.8494947E−19


A14
 2.5807864E−18
−1.4230041E−20
 4.5998255E−21


A15
−1.4672685E−19
 2.5927640E−22
−3.8123231E−23


A16
 1.9648262E−21
−1.6718312E−24
 6.8746386E−26









Example 4
A configuration and a movement trajectory of a zoom lens of Example 4 are illustrated in FIG. 9. The zoom lens of Example 4 has the same configuration as the summary of the zoom lens of Example 3. For the zoom lens of Example 4, fundamental lens data is shown in Table 10A and Table 10B, specifications and variable surface intervals are shown in Table 11, aspherical coefficients are shown in Table 12, and each aberration diagram is illustrated in FIG. 10.







TABLE 10A







Example 4












Sn
R
D
Nd
d
gF















 1
−36008.04337
4.400
1.83400
37.18
0.57780


 2
378.86570
2.000





 3
376.42706
18.131
1.43387
95.18
0.53733


 4
−1223.16988
0.120





 5
818.14991
8.613
1.43875
94.94
0.53433


 6
−2301.80775
27.161





 7
388.21899
15.567
1.43387
95.18
0.53733


 8
−2513.81139
0.120





 9
276.19329
15.665
1.43875
94.94
0.53433


10
1912.08396
1.470





11
174.56396
15.189
1.43875
94.94
0.53433


12
393.61945
DD[12]





*13 
−689.22713
2.500
1.90620
36.05
0.58080


14
44.65746
6.183





15
−140.72112
1.500
1.90619
37.80
0.57584


16
76.48503
4.400





17
−81.78691
1.500
1.81247
40.07
0.57232


18
126.90606
4.663
1.80690
22.81
0.63049


19
−142.56847
DD[19]





20
118.59802
10.893
1.82922
21.82
0.63511


21
−34.74526
1.500
1.95000
33.07
0.58811


22
200.60599
4.020
1.59410
60.47
0.55516


23
−334.12641
DD[23]





24
244.29768
10.779
1.43700
95.10
0.53364


*25 
−123.81759
0.120





26
599.47022
5.200
1.41390
100.82
0.53373


27
−350.29665
2.020
1.69220
29.64
0.60116


28
−2944.90692
DD[28]





29
100.62182
12.961
1.43700
95.10
0.53364


30
−583.48762
0.227





*31 
362.03413
4.791
1.43700
95.10
0.53364


32
−557.09258
0.120





33
251.93172
2.000
1.87633
36.03
0.58082


34
89.93057
14.320
1.43700
95.10
0.53364


35
−164.45465
DD[35]



















TABLE 10B







Example 4












Sn
R
D
Nd
νd
θgF















36 (St)
∞
5.488





37
−124.74549
2.193
1.73778
54.22
0.54363


38
106.94709
0.120





39
43.02425
6.079
1.83076
23.46
0.62245


40
79.98480
4.835





41
−3145.16912
2.446
1.71863
47.72
0.55989


42
81.36354
11.327





43
−453.06834
1.537
1.85046
34.24
0.58719


44
28.61001
7.456
1.72463
31.52
0.59910


45
−132.63507
2.116





46
−59.64035
1.522
1.82708
46.44
0.55731


47
45.48292
7.364
1.56064
48.24
0.56321


48
−60.92361
0.120





49
118.65254
8.276
1.89115
21.12
0.62734


50
3852.05531
12.097





51
253.74777
6.697
1.64109
59.45
0.54233


52
−52.71089
0.120





53
−1064.61974
3.818
1.93617
34.38
0.58474


54
39.44576
0.120





55
38.80144
12.439
1.45734
86.56
0.50306


56
−112.87571
0.120





57
67.68486
5.510
1.74321
30.58
0.59777


58
−63.22808
1.800
1.97233
16.64
0.66592


59
−258.70498
0.250





60
∞
1.000
1.51633
64.14
0.53531


61
∞
11.744





62
∞
33.000
1.60863
46.60
0.56787


63
∞
13.200
1.51633
64.05
0.53463


64
∞
5.509
















TABLE 11







Example 4













WIDE
MIDDLE
TELE
















Zr
1.0
28.0
125.2



f
8.105
226.929
1014.614



Bf
47.382
47.382
47.382



FNo.
1.76
1.80
5.24



2ω (°)
71.6
2.8
0.6



DD[12]
2.463
169.812
183.787



DD[19]
1.682
1.882
1.683



DD[23]
299.727
70.296
2.748



DD[28]
13.130
16.258
2.635



DD[35]
2.060
60.814
128.209

















TABLE 12







Example 4










Sn
13
25
31





KA
 1.0000000E+00
 1.0000000E+00
 1.0000000E+00


A3 
 0.0000000E+00
 0.0000000E+00
 0.0000000E+00


A4 
 6.3438393E−07
 2.0128702E−07
−2.9550844E−07


A5 
 7.6791228E−08
−9.8169288E−09
 1.3826476E−08


A6 
−7.7309931E−09
 1.5316378E−09
−1.6688302E−09


A7 
−3.1643996E−10
−1.7021879E−10
 1.3398339E−11


A8 
 1.5912916E−10
 8.4370119E−12
 5.7440881E−12


A9 
−1.7172261E−11
−9.8454833E−14
−2.5059424E−13


A10
 7.0064058E−13
−4.3453113E−15
−9.5003421E−16


A11
 1.8606267E−14
 5.5846966E−17
 2.3332275E−16


A12
−2.8394809E−15
 3.5313772E−19
−1.0776179E−18


A13
 6.5234868E−17
 2.7502736E−19
−1.8494947E−19


A14
 2.5807864E−18
−1.4230041E−20
 4.5998255E−21


A15
−1.4672685E−19
 2.5927640E−22
−3.8123231E−23


A16
 1.9648262E−21
−1.6718312E−24
 6.8746386E−26









Example 5
A configuration and a movement trajectory of a zoom lens of Example 5 are illustrated in FIG. 11. The zoom lens of Example 5 has the same configuration as the summary of the zoom lens of Example 1. For the zoom lens of Example 5, fundamental lens data is shown in Table 13A and Table 13B, specifications and variable surface intervals are shown in Table 14, aspherical coefficients are shown in Table 15, and each aberration diagram is illustrated in FIG. 12.







TABLE 13A







Example 5












Sn
R
D
Nd
νd
θgF















 1
−1247.24500
4.400
1.83481
42.73
0.56481


 2
378.17990
2.000





 3
384.66501
23.905
1.43387
95.18
0.53733


 4
−620.71480
0.120





 5
607.95739
13.672
1.43387
95.18
0.53733


 6
−1635.54315
22.044





 7
357.64078
18.727
1.43387
95.18
0.53733


 8
−2323.86403
0.120





 9
333.52184
16.884
1.43875
94.94
0.53433


10
∞
2.271





11
172.83587
16.561
1.43875
94.94
0.53433


12
362.63143
DD[12]





*13 
435.75278
1.862
1.90366
31.31
0.59481


14
53.61935
5.888





15
−124.90000
1.800
1.87070
40.73
0.56825


16
43.07230
3.495
1.49700
81.61
0.53887


17
85.30127
5.072





18
−60.50976
1.820
1.88300
40.76
0.56679


19
−3479.99444
2.391
1.94595
17.98
0.65460


20
−138.69469
0.120





21
217.53448
10.316
1.80518
25.42
0.61616


22
−31.70522
1.820
1.80400
46.53
0.55775


23
−931.64568
DD[23]





24
197.33862
11.635
1.49700
81.54
0.53748


*25 
−116.78713
0.120





26
338.03978
8.590
1.43700
95.10
0.53364


27
−154.07793
1.820
1.59270
35.31
0.59336


28
903.60083
DD[28]





29
102.17632
12.042
1.43700
95.10
0.53364


30
−357.01739
1.488





*31 
190.97599
4.923
1.43700
95.10
0.53364


32
−1341.73050
0.305





33
183.93205
3.502
1.80440
39.59
0.57297


34
71.03957
11.361
1.43700
95.10
0.53364


35
−596.98574
DD[35]



















TABLE 13B







Example 5












Sn
R
D
Nd
νd
θgF















36 (St)
∞
5.210





37
−179.42575
1.800
1.80139
45.45
0.55814


38
82.74660
5.282





39
49.90039
3.622
1.84666
23.78
0.61923


40
297.42629
2.442





41
−112.44053
1.800
1.80400
46.53
0.55775


42
136.69219
13.203





43
−108.07011
6.051
1.72916
54.09
0.54490


44
25.68443
8.831
1.63980
34.47
0.59233


45
−54.46125
3.071





46
−46.99407
1.988
1.77250
49.60
0.55212


47
39.66945
6.922
1.54814
45.78
0.56859


48
−55.57389
0.120





49
884.41655
2.120
1.51742
52.43
0.55649


50
−144.84593
7.934





51
−97.87116
3.030
1.48749
70.24
0.53007


52
−42.84697
4.043





53
1151.08531
1.800
1.96300
24.11
0.62126


54
57.15854
7.468





55
74.21323
7.643
1.51742
52.43
0.55649


56
−35.33831
0.135





57
62.39042
6.337
1.54072
47.23
0.56511


58
−44.23377
2.258
2.00069
25.46
0.61364


59
−162.17197
0.250





60
∞
1.000
1.51633
64.14
0.53531


61
∞
11.899





62
∞
33.000
1.60859
46.44
0.56664


63
∞
13.200
1.51633
64.05
0.53463


64
∞
5.510
















TABLE 14







Example 5













WIDE
MIDDLE
TELE
















Zr
1.0
21.6
120.6



f
8.297
179.363
1000.855



Bf
47.539
47.539
47.539



FNo.
1.76
1.79
5.19



2ω (°)
70.2
3.4
0.6



DD[12]
2.399
162.308
181.594



DD[23]
297.098
80.665
2.945



DD[28]
2.497
11.964
6.252



DD[35]
2.279
49.336
113.482

















TABLE 15







Example 5










Sn
13
25
31





KA
 1.0000000E+00
 1.0000000E+00
 1.0000000E+00


A3 
 0.0000000E+00
 0.0000000E+00
 0.0000000E+00


A4 
−2.0418640E−08
 1.6774969E−07
−2.1898905E−07


A5 
 1.7997276E−07
−8.4229260E−10
−1.3844130E−09


A6 
−4.5437887E−08
−2.0469494E−12
 1.2931566E−09


A7 
 6.6751364E−09
−6.4965005E−13
−2.4165943E−10


A8 
−5.9456491E−10
 3.8125842E−15
 1.8466846E−11


A9 
 3.4600193E−11
 2.1729178E−15
−6.7241617E−13


A10
−1.7060286E−12
 1.3528170E−17
 8.4080445E−15


A11
 9.6566222E−14
−1.6168407E−18
 1.6635466E−16


A12
−4.4727077E−15
−1.1639852E−19
−6.6941235E−18


A13
 8.4045374E−17
 6.8007151E−21
 1.2311712E−19


A14
 2.0761838E−18
−1.5682732E−22
−3.5545539E−21


A15
−1.1818133E−19
 2.2116854E−24
 7.7910896E−23


A16
 1.4620255E−21
−1.5630382E−26
−6.2738171E−25









Table 16 shows corresponding values of Conditional Expressions (1) to (7) of the zoom lenses of Examples 1 to 5.













TABLE 16





Expression








Number

Example 1
Example 2
Example 3
Example 4
Example 5





















(1)
f1/fNw
−10.127
−10.121
−10.081
−10.219
−9.923


(2)
fP2/fP1
0.774
0.673
0.674
0.676
0.806


(3)
νn
35.27
35.31
35.31
29.64
35.31


(4)
νp
95.10
95.10
95.10
100.82
95.10


(5)
θp + 0.001625 × νp
0.6882
0.6882
0.6882
0.6976
0.6882


(6)
fn/fP1
−1.427
−2.961
−2.914
−3.109
−1.423


(7)
Ndn
1.59270
1.59270
1.59270
1.69220
1.59270









As is perceived from the data described above, even in a case where the zoom lenses of Examples 1 to 5 are configured in a small size, the zoom magnification is greater than or equal to a power of 120, and a high magnification is achieved. In addition, high optical characteristics are implemented by suppressing a change in aberration during zooming and favorably correcting various types of aberration.
Next, an imaging apparatus according to the embodiment of the present disclosure will be described. FIG. 13 illustrates a schematic configuration diagram of an imaging apparatus 100 using a zoom lens 1 according to the embodiment of the present disclosure as one example of the imaging apparatus according to the embodiment of the present disclosure. For example, a broadcasting camera, a movie imaging camera, a video camera, and a monitoring camera can be exemplified as the imaging apparatus 100.
The imaging apparatus 100 comprises the zoom lens 1, a filter 2 arranged on the image side of the zoom lens 1, and an imaging element 3 arranged on the image side of the filter 2. In FIG. 13, a plurality of lenses comprised in the zoom lens 1 are schematically illustrated.
The imaging element 3 converts an optical image formed by the zoom lens 1 into an electric signal and can use, for example, a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). The imaging element 3 is arranged such that an imaging surface thereof matches an image surface of the zoom lens 1.
The imaging apparatus 100 also comprises a signal processing unit 5 performing calculation processing on an output signal from the imaging element 3, a display unit 6 displaying an image formed by the signal processing unit 5, a zooming control unit 7 controlling zooming of the zoom lens 1, and a focusing control unit 8 controlling focusing of the zoom lens 1. While only one imaging element 3 is illustrated in FIG. 13, a so-called three-plate type imaging apparatus including three imaging elements may also be used.
While the technology of the present disclosure has been illustratively described with the embodiment and the examples, the technology of the present disclosure is not limited to the embodiment and the examples and can be subjected to various modifications. For example, the radius of curvature, the surface interval, the refractive index, the Abbe number, the aspherical coefficient, and the like of each lens are not limited to the values shown in each example of the numerical values and may have other values.

## Claims

1. A zoom lens consisting of, in order from an object side to an image side:
a first lens group that has a positive refractive power and is fixed with respect to an image surface during zooming;
a negative moving lens group that consists of one or two lens groups moved along an optical axis by changing an interval with an adjacent lens group during zooming, and has a negative refractive power as a whole at a wide angle end;
a first positive moving lens group that has a positive refractive power and is moved along the optical axis during zooming;
a second positive moving lens group that has a positive refractive power and is moved along the optical axis during zooming; and
a subsequent lens group including a stop,
wherein all intervals between adjacent lens groups are changed during zooming,
all lens groups included in the negative moving lens group are moved to the image side during zooming from the wide angle end to a telephoto end,
the first positive moving lens group consists of a single lens that is a positive lens, and a cemented lens configured by cementing two lenses in which any one is a positive lens and the other is a negative lens,
in a state where an object at infinity is focused, in a case where a focal length of the first lens group is denoted by f1, a focal length of the negative moving lens group at the wide angle end is denoted by fNw, a focal length of the first positive moving lens group is denoted by fP1, and a focal length of the second positive moving lens group is denoted by fP2, Conditional Expressions (1a) and (2) are satisfied, which are represented by


−11.5<f1/fNw≤−9.923  (1a)



0.5<fP2/fP1<1  (2),



and
in a state where an object at infinity is focused, in a case where a focal length of the negative lens of the first positive moving lens group is denoted by fn, and the focal length of the first positive moving lens group is denoted by fP1, Conditional Expression (6) is satisfied, which is represented by


−4<fn/fP1<−1  (6),



and
in a case where a d line-based Abbe number of a positive lens of which the d line-based Abbe number is largest out of the positive lenses included in the first positive moving lens group is denoted by νp, and a partial dispersion ratio, between g line and F line, of the positive lens of which the d line-based Abbe number is largest out of the positive lenses included in the first positive moving lens group is denoted by θp, Conditional Expressions (4) and (5) are satisfied, which are represented by


80<νp  (4)



0.66<θp+0.001625×νp<0.72  (5).

2. The zoom lens according to claim 1,
wherein in a case where a d line-based Abbe number of the negative lens of the first positive moving lens group is denoted by νn, Conditional Expression (3) is satisfied, which is represented by


20<νn<40  (3).

3. The zoom lens according to claim 2,
wherein Conditional Expression (3-1) is satisfied, which is represented by


25<νn<37  (3-1).

4. The zoom lens according to claim 1,
wherein in a case where a refractive index of the negative lens of the first positive moving lens group with respect to d line is denoted by Ndn, Conditional Expression (7) is satisfied, which is represented by


1.55<Ndn<1.77  (7).

5. The zoom lens according to claim 4,
wherein Conditional Expression (7-1) is satisfied, which is represented by


1.57<Ndn<1.7  (7-1).

6. The zoom lens according to claim 1,
wherein the second positive moving lens group at the telephoto end is positioned on the object side from the second positive moving lens group at the wide angle end, and
in a state where an object at infinity is focused, an interval between the first positive moving lens group and the second positive moving lens group is largest on a wide angle side from a zoom position at which a lateral magnification of a combined lens group obtained by combining the first positive moving lens group and the second positive moving lens group is −1.

7. The zoom lens according to claim 1,
wherein in a state where an object at infinity is focused, during zooming from the wide angle end to the telephoto end, a combined lens group obtained by combining the first positive moving lens group and the second positive moving lens group, and the negative moving lens group simultaneously pass through respective points at which lateral magnifications are −1.

8. The zoom lens according to claim 1,
wherein the negative moving lens group consists of one lens group having a negative refractive power.

9. The zoom lens according to claim 1,
wherein the negative moving lens group consists of one lens group having a negative refractive power and one lens group having a positive refractive power in order from the object side to the image side.

10. The zoom lens according to claim 1,
wherein the first lens group comprises at least one lens that is moved along the optical axis during focusing.

11. The zoom lens according to claim 1,
wherein Conditional Expression (1-1a) is satisfied, which is represented by


−11<f1/fNw≤−9.923  (1-1a).

12. The zoom lens according to claim 1,
wherein Conditional Expression (2-1) is satisfied, which is represented by


0.6<fP2/fP1<0.9  (2-1).

13. The zoom lens according to claim 1,
wherein Conditional Expression (4-1) is satisfied, which is represented by


90<νp<105  (4-1).

14. The zoom lens according to claim 1,
wherein Conditional Expression (5-1) is satisfied, which is represented by


0.67<θp+0.001625×νp<0.7  (5-1).

15. The zoom lens according to claim 1,
wherein Conditional Expression (6-1) is satisfied, which is represented by


−3.5<fn/fP1<−1.2  (6-1).

16. An imaging apparatus comprising:
the zoom lens according to claim 1.