JP6964615B2 - Zoom lens and imaging device - Google Patents

Description

The present disclosure relates to a zoom lens and an imaging device.

Conventionally, as a zoom lens used for a broadcasting camera, a movie shooting camera, a digital camera, etc., a lens group having a positive refractive force and a moving lens group moving at the time of magnification change are used in order from the object side. , A type is known in which the entire length of the lens system is invariant at the time of magnification change by arranging a subsequent group including an aperture. For example, Patent Document 1 and Patent Document 2 below describe a zoom lens having a 5-group or 6-group configuration of the above type.

Japanese Unexamined Patent Publication No. 2016-71141 Japanese Unexamined Patent Publication No. 2016-109952

The zoom lens used in the above camera is required to be compact and have high performance. In order to configure the lens in a compact size and with high performance, it is important to shorten the space of the following group as much as possible to secure the zoom stroke of the lens group that moves at the time of magnification change, and to correct various aberrations well. Is. At that time, in order to satisfactorily correct the axial chromatic aberration on the wide-angle side, the arrangement of the refractive power and the selection of the material of the lens of the subsequent group are particularly important. When the axial chromatic aberration that is insufficiently corrected remains in the succeeding group, if the axial chromatic aberration is corrected by the moving lens group on the object side of the succeeding group, the fluctuation of the axial chromatic aberration is suppressed from the wide-angle end to the zoom intermediate region. It becomes difficult to do.

The lens system described in Patent Document 1 has room for improvement in suppressing fluctuations in axial chromatic aberration from the wide-angle end to the intermediate zoom range. The lens system described in Patent Document 2 also has insufficient suppression of fluctuations in axial chromatic aberration from the wide-angle end to the intermediate zoom range, and also has insufficient miniaturization of the entire system.

This disclosure has been made in view of the above circumstances. The problem to be solved by one embodiment of the present invention is a zoom lens having high optical performance in which fluctuations in axial chromatic aberration are satisfactorily suppressed from the wide-angle end to the intermediate zoom range while achieving miniaturization, and this zoom lens. It is an object of the present invention to provide an image pickup apparatus provided with the above.

Specific means for solving the above problems include the following aspects.
<1> The distance between the first lens group having a positive refractive force fixed to the image plane at the time of scaling and the adjacent group at the time of scaling in order from the object side to the image side. At least two moving lenses in the intermediate group, consisting of an intermediate group consisting of two or more moving lens groups that move along the optical axis and a subsequent group that has the lens group including the aperture on the object side most. The group has a negative refractive power, and the subsequent group includes an LA lens which is at least one positive lens, the refractive index of the LA lens at the d-line is NdA, and the abbe number of the LA lens based on the d-line is νdA, LA. When the partial dispersion ratio between the g-line and F-line of the lens is θgFA, the LA lens has 1.72 <NdA <1.84 (1).
43 <νdA <57 (2)
0.62 <θgFA + 0.001625 × νdA <0.66 (3)
2.21 <NdA + 0.01 × νdA (4)
A zoom lens that satisfies the conditional expressions (1), (2), (3), and (4) represented by.

<2> When the succeeding group includes at least one LA lens on the image side of the aperture and the LA lens located closest to the object side of the LA lenses on the image side of the aperture is the LA lens on the most object side, the LA lens is at the wide-angle end. When the distance between the aperture and the LA lens on the most object side on the optical axis is LDW, and the distance between the aperture at the wide-angle end and the lens surface on the image side on the optical axis is SDW.
0.005 <LDW / SDW <0.45 (5)
A zoom lens of <1> that satisfies the conditional expression (5) represented by.

<3> The subsequent group includes an LB lens which is at least one positive lens on the image side of the LA lens on the most object side, the Abbe number of the d-line reference of the LB lens is ν dB, and between the g-line and the F-line of the LB lens. When the partial dispersion ratio is θgFB, the LB lens has 65 <ν dB <105 (6).
0.6355 <θgFB + 0.001625 × νdB <0.7 (7)
A zoom lens of <2> that satisfies the conditional expressions (6) and (7) represented by.

で表される条件式（８）を満足する＜３＞のズームレンズ。 <4> The focal length of the LA lens on the most object side is fA, the total number of LB lenses arranged on the image side of the LA lens on the most object side is k, and the LB lens arranged on the image side of the LA lens on the most object side is on the object side. When the number assigned in order from the object is i, and the focal length of the i-th LB lens from the object side is fBi among the LB lenses arranged on the image side from the LA lens on the most object side,

A zoom lens of <3> that satisfies the conditional expression (8) represented by.

<5> A zoom lens according to any one of <1> to <4>, in which the lens arranged closest to the object in the subsequent group is the LA lens.

<6> A zoom lens according to any one of <1> to <5>, wherein the object-side surface of at least one LA lens included in the subsequent group is a convex surface.

<7> A zoom lens according to any one of <1> to <6>, in which focusing is performed by moving at least a part of the lenses in the first lens group along the optical axis.

<8> The zoom lens according to any one of <1> to <7> in which the moving lens group on the image side in the intermediate group has a negative refractive power.

<9> The intermediate group consists of a group of moving lenses having two negative refractive powers, and the subsequent group consists of a group of lenses having a positive refractive power fixed to the image plane at the time of scaling. 8> zoom lens.

<10> The intermediate group consists of a group of moving lenses having two negative refractive powers, and the subsequent group changes the distance between the adjacent groups at the time of scaling in order from the object side to the image side. A <8> zoom lens consisting of a lens group having a positive refractive power that moves along the optical axis and a lens group having a positive refractive power that is fixed to the image plane at the time of scaling.

<11> The intermediate group consists of a group of moving lenses having three negative refractive powers, and the subsequent group consists of a group of lenses having a refractive power fixed to the image plane at the time of scaling <8>. Zoom lens.

<12> The intermediate group consists of four moving lens groups having negative refractive power, and the subsequent group consists of lens groups having positive refractive power fixed to the image plane at the time of scaling. 8> zoom lens.

<13> The moving lens group having at least one negative refractive power in the intermediate group includes at least one negative lens, the LN lens, and the refractive index of the LN lens at the d-line is Ndn, based on the d-line of the LN lens. When the Abbe number of the LN lens is νdn and the partial dispersion ratio between the g-line and the F-line of the LN lens is θgFn, the LN lens has 1.72 <Ndn <1.8 (9).
43 <νdn <57 (10)
0.6355 <θgFn + 0.001625 × νdn <0.66 (11)
2.21 <Ndn + 0.01 × νdn (12)
A zoom lens according to any one of <1> to <12> that satisfies the conditional expressions (9), (10), (11), and (12) represented by.

<14> LA lens is further 45 <νdA <55 (2-1)
A zoom lens according to any one of <1> to <13> that satisfies the conditional expression (2-1) represented by.

<15> The LA lens is further 0.637 <θgFA + 0.001625 × νdA <0.65 (3-1).
A zoom lens according to any one of <1> to <14> that satisfies the conditional expression (3-1) represented by.

<16> The LA lens is further 2.21 <NdA + 0.01 × νdA <2.33 (4-1)
A zoom lens according to any one of <1> to <15> that satisfies the conditional expression (4-1) represented by.

<17> 0.005 <LDW / SDW <0.2 (5-1)
A zoom lens of <2> that satisfies the conditional expression (5-1) represented by.

で表される条件式（８−１）を満足する＜４＞のズームレンズ。 <18>

A zoom lens of <4> that satisfies the conditional expression (8-1) represented by.

<19> An imaging device including any of the zoom lenses <1> to <18>.

In addition to the components listed above, "consisting of" and "consisting of" in the present specification refer to lenses having substantially no refractive power, and lenses such as an aperture, a filter, and a cover glass. It is intended that optical elements other than the above, as well as mechanical parts such as a lens flange, a lens barrel, an image pickup element, and an image stabilization mechanism, and the like may be included.

In addition, the "group having a positive refractive power" in the present specification means that the group as a whole has a positive refractive power. Similarly, the "group having a negative refractive power" means that the group as a whole has a negative refractive power. "Lens with positive refractive power" and "positive lens" are synonymous. "Lens with negative refractive power" and "negative lens" are synonymous. The "lens group" is not limited to a configuration consisting of a plurality of lenses, and may be a configuration consisting of only one lens. Further, the "one lens group" is defined as a "one lens group" in which the distance between the adjacent groups and the adjacent groups in the optical axis direction changes at the time of magnification change. That is, when the lens group is divided at intervals that change at the time of magnification change, the lens group included in one division is regarded as one lens group.

A compound aspherical lens (a lens in which a spherical lens and an aspherical film formed on the spherical lens are integrally formed and function as one aspherical lens as a whole) is regarded as a junction lens. Instead, treat it as a single lens. Unless otherwise specified, the sign of the refractive power and the surface shape of the lens surface of the lens including the aspherical surface will be considered in the paraxial region.

The "focal length" used in the conditional expression is the paraxial focal length. The value used in the conditional expression is a value when the d line is used as a reference in a state where the object is in focus at infinity. The partial dispersion ratio θgF between the g-line and the F-line of a lens is θgF = (Ng−) when the refractive indexes of the lens with respect to the g-line, F-line, and C-line are Ng, NF, and NC, respectively. It is defined by NF) / (NF-NC). The "d line", "C line", "F line", and "g line" described in the present specification are emission lines, the wavelength of the d line is 587.56 nm (nanometers), and the wavelength of the C line is 656. The wavelength of the F line is .27 nm (nanometers), the wavelength of the F line is 486.13 nm (nanometers), and the wavelength of the g line is 435.84 nm (nanometers).

According to one embodiment of the present invention, a zoom lens having high optical performance in which fluctuations in axial chromatic aberration are satisfactorily suppressed from the wide-angle end to the middle zoom region while achieving miniaturization, and an image pickup provided with this zoom lens. Equipment can be provided.

It is a figure which corresponds to the zoom lens of Example 1 of this invention, and shows the cross-sectional view and the movement locus of the structure of the zoom lens which concerns on one Embodiment of this invention. It is sectional drawing which shows the structure and the luminous flux of the zoom lens shown in FIG. It is a figure which shows the cross-sectional view of the structure of the zoom lens of Example 2 of this invention, and the movement locus. It is a figure which shows the cross-sectional view of the structure of the zoom lens of Example 3 of this invention, and the movement locus. It is a figure which shows the cross-sectional view and the movement locus of the structure of the zoom lens of Example 4 of this invention. It is a figure which shows the cross-sectional view and the movement locus of the structure of the zoom lens of Example 5 of this invention. It is a figure which shows the cross-sectional view and the movement locus of the structure of the zoom lens of Example 6 of this invention. It is each aberration diagram of the zoom lens of Example 1 of this invention. It is each aberration diagram of the zoom lens of Example 2 of this invention. It is each aberration diagram of the zoom lens of Example 3 of this invention. It is each aberration diagram of the zoom lens of Example 4 of this invention. It is each aberration diagram of the zoom lens of Example 5 of this invention. It is each aberration diagram of the zoom lens of Example 6 of this invention. It is a schematic block diagram of the image pickup apparatus which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the zoom lens of the present disclosure will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a configuration and a movement locus of a zoom lens according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a lens configuration and a luminous flux in each state of the zoom lens. The examples shown in FIGS. 1 and 2 correspond to the zoom lens of the first embodiment described later. In FIGS. 1 and 2, the state of focusing on an infinity object is shown, the left side is the object side, and the right side is the image side. FIG. 1 shows a wide-angle end state. In FIG. 2, the upper row labeled "wide-angle end" shows the wide-angle end state, the middle row labeled "middle" shows the intermediate focal length state, and the lower row labeled "telephoto end" shows the telephoto end state. In FIG. 2, as the luminous flux, the axial luminous flux wa and the maximum angle of view light flux wb in the wide angle end state, the axial luminous flux ma and the maximum angle of view luminous flux mb in the intermediate focal distance state, and the axial luminous flux ta and the maximum in the telescopic end state. The luminous flux tb of the angle of view is shown.

Further, in FIGS. 1 and 2, assuming that the zoom lens is applied to the image pickup apparatus, an example in which the optical member PP whose entrance surface and exit surface are parallel to each other is arranged between the zoom lens and the image plane Sim. Is shown. The optical member PP is a member that assumes various filters, prisms, and / or cover glass and the like. The various filters include, for example, a low-pass filter, an infrared cut filter, a filter that cuts a specific wavelength range, and the like. The optical member PP is a member having no refractive power, and a configuration in which the optical member PP is omitted is also possible. Hereinafter, the description will be made mainly with reference to FIG.

The zoom lens of the present disclosure includes a first lens group G1, an intermediate group Gm, and a succeeding group Gs in order from the object side to the image side along the optical axis Z. The first lens group G1 is a lens group that is fixed to the image plane Sim at the time of scaling and has a positive refractive power. The intermediate group Gm is composed of two or more moving lens groups that move along the optical axis Z by changing the distance between adjacent groups at the time of scaling. That is, the intermediate group Gm is composed of two or more moving lens groups that move along the optical axis Z on different trajectories at the time of scaling. At least two moving lens groups within the intermediate group Gm have a negative refractive power. The subsequent group Gs has a lens group including the aperture stop St on the most object side.

By making the lens group on the most object side a lens group having a positive refractive power, the total length of the lens system (the distance on the optical axis from the lens surface on the most object side to the image plane Sim) can be shortened, resulting in miniaturization. It becomes advantageous to. Furthermore, by adopting a configuration in which the lens group having the most positive refractive power on the object side is fixed at the time of magnification change, the overall length of the lens system does not change at the time of magnification change, and the fluctuation of the center of gravity of the lens system is reduced. Therefore, it is possible to improve the convenience at the time of shooting. Further, by arranging two or more moving lens groups having a negative refractive power on the object side of the lens group including the aperture aperture St, the refractive power of the negative moving lens group having a chromatic aberration effect can be dispersed. , Fluctuations in spherical aberration and chromatic aberration during scaling can be suppressed. This is advantageous in achieving both high magnification and shortening of the overall length of the lens system.

The zoom lens of the example shown in FIG. 1 has a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a negative refractive power in this order from the object side to the image side. It is composed of a third lens group G3 having a refractive power and a fourth lens group G4 having a refractive power. At the time of scaling, the first lens group G1 and the fourth lens group G4 are fixed to the image plane Sim. The second lens group G2 and the third lens group G3 are moving lens groups that move along the optical axis Z by changing the distance between adjacent groups at the time of scaling. An aperture diaphragm St is arranged on the most object side of the fourth lens group G4. The aperture stop St shown in FIG. 1 does not indicate the shape, but indicates the position in the optical axis direction. In the example shown in FIG. 1, the group consisting of the second lens group G2 and the third lens group G3 corresponds to the intermediate group Gm, and the fourth lens group G4 corresponds to the succeeding group Gs. In FIG. 1, the moving locus of each moving lens group when scaling from the wide-angle end to the telephoto end is schematically shown by an arrow under the moving lens group.

In the example shown in FIG. 1, the first lens group G1 is composed of 11 lenses of lenses L1a to L1k in order from the object side to the image side, and the second lens group G2 is directed from the object side to the image side. The third lens group G3 is composed of two lenses L3a to L3b in order from the object side to the image side, and the fourth lens group G4 is composed of six lenses L2a to L2f. The lens is composed of an aperture aperture St and nine lenses L4a to L4i in this order from the object side to the image side. However, in the zoom lens of the present disclosure, the number of lens groups constituting the intermediate group Gm and the succeeding group Gs, the number of lenses constituting each lens group, and the position of the aperture diaphragm St are different from the example shown in FIG. It is also possible to make it.

In the zoom lens of the present disclosure, the subsequent group Gs includes at least one positive lens, the LA lens LA. When the refractive index of the LA lens LA on the d line is NdA, the Abbe number of the LA lens LA based on the d line is ν dA, and the partial dispersion ratio between the g line and the F line of the LA lens LA is θgFA, the LA lens LA is as follows. It is a lens that satisfies the conditional equations (1), (2), (3), and (4).
1.72 <NdA <1.84 (1)
43 <νdA <57 (2)
0.62 <θgFA + 0.001625 × νdA <0.66 (3)
2.21 <NdA + 0.01 × νdA (4)

The conditional expressions (1), (2), (3), and (4) are conditional expressions relating to the material of the LA lens LA. Since a material having a high refractive index can be selected by not falling below the lower limit of the conditional expression (1), it is easy to satisfactorily correct the spherical aberration on the wide-angle side while achieving miniaturization and high magnification. It becomes. Since a material with low dispersion can be selected by not exceeding the upper limit of the conditional expression (1), it becomes easy to satisfactorily correct the axial chromatic aberration on the wide-angle side, and the axial chromatic aberration is satisfactorily corrected from the wide-angle end to the zoom intermediate region. It becomes easy to suppress fluctuations in chromatic aberration.

By making sure that the material does not fall below the lower limit of the conditional expression (2), a material with low dispersion can be selected, so that it becomes easy to satisfactorily correct the axial chromatic aberration on the wide-angle side, and the axial chromatic aberration is satisfactorily corrected from the wide-angle end to the zoom intermediate region. It becomes easy to suppress fluctuations in chromatic aberration. Since a material having a high refractive index can be selected by not exceeding the upper limit of the conditional expression (2), it is easy to satisfactorily correct the spherical aberration on the wide-angle side while achieving miniaturization and high magnification. It becomes. If the configuration satisfies the following conditional expression (2-1), better characteristics can be obtained.
45 <νdA <55 (2-1)

By satisfying the conditional expression (3), it becomes easy to satisfactorily correct the secondary axial chromatic aberration on the wide-angle side. If the configuration satisfies the following conditional expression (3-1), better characteristics can be obtained.
0.637 <θgFA + 0.001625 × νdA <0.65 (3-1)

By satisfying the above conditional equations (1) and (2) and not being below the lower limit of the conditional equation (4), while achieving miniaturization and high magnification, spherical aberration on the wide-angle side and on the axis are achieved. It becomes easy to satisfactorily correct chromatic aberration. In order to select a suitable material that satisfies the above conditional expressions (1) and (2) from the existing optical materials, it is preferable to satisfy the following conditional expression (4-1).
2.21 <NdA + 0.01 × νdA <2.33 (4-1)

For example, in the example shown in FIG. 1, the lens L4a corresponds to the LA lens LA. However, in the zoom lens of the present disclosure, the LA lens LA can be different from the example shown in FIG.

The lens arranged on the most object side of the succeeding group Gs may be configured to be the LA lens LA. In this case, it becomes easy to satisfactorily correct the spherical aberration and the axial chromatic aberration on the wide-angle side while shortening the space of the succeeding group Gs.

The object-side surface of at least one LA lens LA included in the subsequent group Gs is preferably a convex surface. In this case, it becomes easy to satisfactorily correct the spherical aberration on the wide-angle side while shortening the space of the subsequent group Gs.

Subsequent groups Gs may be configured to include an LA lens LA having at least one aspherical surface. In this case, it becomes easy to satisfactorily correct the spherical aberration on the wide-angle side.

Further, it is preferable that the succeeding group Gs includes at least one LA lens LA on the image side of the aperture stop St. In this case, it becomes easy to both correct the axial chromatic aberration on the wide-angle side and the correction of the chromatic aberration of magnification.

In the following, the LA lens LA located closest to the object side of the LA lens LA on the image side of the aperture stop St will be referred to as the LA lens on the most object side. When at least one LA lens LA is arranged on the image side of the aperture stop St, the distance between the aperture stop St at the wide-angle end and the LA lens on the most object side on the optical axis is set to LDW, and the aperture stop St at the wide-angle end. When the distance on the optical axis from the lens surface on the image side is SDW, it is preferable that the following conditional expression (5) is satisfied. By making sure that the value does not fall below the lower limit of the conditional expression (5), it becomes easy to secure a space for providing an aperture diaphragm mechanism that changes the aperture diameter of the aperture diaphragm St in order to make the amount of incident light variable. By including at least one LA lens LA on the image side of the aperture stop St and not exceeding the upper limit of the conditional expression (5), it is easy to both correct the axial chromatic aberration and the Magnification chromatic aberration on the wide-angle side. Become. If the configuration satisfies the following conditional expression (5-1), better characteristics can be obtained.
0.005 <LDW / SDW <0.45 (5)
0.005 <LDW / SDW <0.2 (5-1)

When at least one LA lens LA is arranged on the image side of the aperture stop St and the above conditional expression (5) is satisfied, the succeeding group Gs has at least one positive image side of the LA lens LA on the most object side. It is preferable to include an LB lens which is a lens. When the Abbe number based on the d-line of the LB lens LB is ν dB and the partial dispersion ratio between the g-line and the F-line of the LB lens LB is θgFB, the LB lens LB satisfies the following conditional equations (6) and (7). It is a lens.
65 <ν dB <105 (6)
0.6355 <θgFB + 0.001625 × νdB <0.7 (7)

The conditional expressions (6) and (7) are conditional expressions relating to the material of the LB lens LB. By satisfying the conditional expression (6), it becomes easy to satisfactorily correct the primary axial chromatic aberration on the wide-angle side. Further, it becomes easy to both correct the axial chromatic aberration on the wide-angle side and the correction of the chromatic aberration of magnification. By satisfying the conditional expression (7), it becomes easy to satisfactorily correct the secondary axial chromatic aberration on the wide-angle side.

By including at least one LB lens LB on the image side of the LA lens LA on the most object side, the subsequent group Gs has the effect of correcting the axial chromatic aberration on the wide-angle side by the LA lens LA, and the axial chromatic aberration and the axial chromatic aberration by the LB lens LB. Both the effect of correcting chromatic aberration of magnification and the effect of correction can be obtained.

For example, in the example shown in FIG. 1, the lens L4g and the lens L4i correspond to the LB lens LB. However, in the zoom lens of the present disclosure, the LB lens LB can be different from the example shown in FIG.

Further, the focal length of the LA lens LA on the most object side is fA, the total number of LB lenses LB arranged on the image side of the LA lens LA on the most object side is k, and the LB lens arranged on the image side of the LA lens on the most object side. When the number assigned in order from the object side is i, and the focal length of the i-th LB lens LB from the object side is fBi among the LB lens LBs arranged on the image side from the LA lens LA on the most object side, the following conditional expression is used. It is preferable to satisfy (8). By satisfying the conditional expression (8), it becomes easy to satisfactorily correct the primary axial chromatic aberration and the secondary axial chromatic aberration on the wide-angle side. In addition, it becomes easy to achieve both axial chromatic aberration and chromatic aberration of magnification on the wide-angle side. If the configuration satisfies the following conditional expression (8-1), better characteristics can be obtained.

Further, it is preferable that the moving lens group having at least one negative refractive power in the intermediate group Gm includes at least one negative lens, the LN lens. When the refractive index of the LN lens LN at the d line is Ndn, the Abbe number of the LN lens LN based on the d line is νdn, and the partial dispersion ratio between the g line and the F line of the LN lens LN is θgFn, the LN lens LN is as follows. It is a lens that satisfies the conditional equations (9), (10), (11), and (12).
1.72 <Ndn <1.8 (9)
43 <νdn <57 (10)
0.6355 <θgFn + 0.001625 × νdn <0.66 (11)
2.21 <Ndn + 0.01 × νdn (12)

The conditional expressions (9), (10), (11), and (12) are conditional expressions relating to the material of the LN lens LN. Since a material having a high refractive index can be selected by making sure that the value does not fall below the lower limit of the conditional expression (9), fluctuations in various aberrations during magnification change are satisfactorily suppressed while achieving miniaturization and high magnification. It becomes easy to do. By not exceeding the upper limit of the conditional expression (9), a material having a low dispersion can be selected, so that it becomes easy to satisfactorily suppress fluctuations in chromatic aberration during scaling.

By making sure that the value does not fall below the lower limit of the conditional expression (10), a material having a low dispersion can be selected, so that it becomes easy to satisfactorily suppress fluctuations in chromatic aberration during scaling. Since a material having a high refractive index can be selected by not exceeding the upper limit of the conditional expression (10), fluctuations in various aberrations during scaling are satisfactorily suppressed while achieving miniaturization and high magnification. It becomes easy to do. If the configuration satisfies the following conditional expression (10-1), better characteristics can be obtained.
45 <νdn <55 (10-1)

By satisfying the conditional expression (11), it becomes easy to satisfactorily suppress the fluctuation of the secondary chromatic aberration at the time of scaling. If the configuration satisfies the following conditional expression (11-1), better characteristics can be obtained.
0.637 <θgFn + 0.001625 × νdn <0.65 (11-1)

By satisfying the above conditional equations (9) and (10) and not being below the lower limit of the conditional equation (12), chromatic aberration at the time of variable magnification is included while achieving miniaturization and high magnification. It becomes easy to suppress fluctuations of various aberrations satisfactorily. In order to select a suitable material that satisfies the above conditional expressions (9) and (10) from the existing optical materials, it is preferable to satisfy the following conditional expression (12-1).
2.21 <Ndn + 0.01 × νdn <2.33 (12-1)

For example, in the example shown in FIG. 1, the lens L2d corresponds to the LN lens LN. However, in the zoom lens of the present disclosure, the LN lens LN can be different from the example shown in FIG.

The first lens group G1 preferably includes a focus group, which is a lens group that moves during focusing. That is, it is preferable that focusing is performed by moving at least a part of the lenses in the first lens group G1 along the optical axis Z. Since the first lens group G1 is immovable at the time of magnification change, if at least a part of the lenses in the first lens group G1 are set as the focus group, the image point of the focus group becomes immovable at the time of magnification change. , It is possible to suppress the out-of-focus at the time of scaling.

The zoom lens of the present disclosure preferably includes a vibration isolation group, which is a lens group that corrects image blur by moving in a direction intersecting the optical axis on the image side of the aperture diaphragm St. In the configuration including this anti-vibration group, when the focal length of the anti-vibration group is false and the focal length of the zoom lens at the telephoto end in the state of being in focus on an infinity object is fT, the following conditional expression (13) is satisfied. It is preferable to do so. By making sure that the value does not fall below the lower limit of the conditional expression (13), it becomes easy to suppress fluctuations in spherical aberration and axial chromatic aberration from the wide-angle end to the intermediate zoom region. When the device is equipped with an optical anti-vibration mechanism, the size of the device tends to be large, but it is advantageous for the device to be miniaturized by not exceeding the upper limit of the conditional expression (13).
0.1 << | fas / fT | <0.2 (13)

Further, in the configuration including the anti-vibration group, when the focal length of the anti-vibration group is fas and the combined focal length of all the lenses on the image side from the longest air interval on the optical axis in the subsequent group Gs is fR, the following conditions are met. It is preferable to satisfy the formula (14). By making sure that the value does not fall below the lower limit of the conditional expression (14), it becomes easy to suppress fluctuations in spherical aberration and axial chromatic aberration from the wide-angle end to the intermediate zoom region. When the device is equipped with an optical anti-vibration mechanism, the size of the device tends to be large, but it is advantageous for the device to be miniaturized by not exceeding the upper limit of the conditional expression (14).
0.5 << fas / fR | <1.2 (14)

The most image-side moving lens group in the intermediate group Gm preferably has a negative refractive power. In this case, when correcting the fluctuation of the image position at the time of magnification change, it is possible to move to the image side on the telephoto side, and the zoom stroke of the moving lens group mainly responsible for the magnification change is secured. This becomes easy, which is advantageous for miniaturization and high magnification.

The intermediate group Gm and the succeeding group Gs can have the configuration described below, for example. The intermediate group Gm consists of a group of moving lenses having two negative refractive powers, and the subsequent group Gs has a positive refractive power that includes the aperture stop St and is fixed to the image plane Sim at the time of scaling. It can be configured to consist of a lens group. In this case, the zoom stroke of the moving lens group becomes small, and the overall length of the lens system can be shortened, which is advantageous for miniaturization.

Alternatively, the intermediate group Gm is composed of two moving lens groups having negative refractive powers, and the succeeding group Gs is a group adjacent to each other at the time of scaling including the aperture aperture St in order from the object side to the image side. The lens group has a positive refractive power that moves along the optical axis Z by changing the interval between the lenses, and the lens group has a positive refractive power that is fixed to the image plane Sim at the time of scaling. Can be configured in. In this case, it becomes easy to suppress fluctuations in various aberrations during miniaturization, high magnification, and variable magnification. Further, in the zoom intermediate region where the off-axis luminous flux is the highest, the moving lens group having a positive refractive power including the aperture stop St can be extended to the object side, so that the lens diameter of the first lens group G1 can be suppressed. Therefore, it is advantageous for miniaturization of the first lens group G1.

Alternatively, the intermediate group Gm is composed of a group of moving lenses having three negative refractive powers, and the subsequent group Gs includes an aperture stop St and has a refractive power fixed to the image plane Sim at the time of scaling. It can be configured to consist of a lens group. In this case, it becomes easy to suppress fluctuations in various aberrations during miniaturization, high magnification, and variable magnification. In particular, it is advantageous in suppressing fluctuations in curvature of field during scaling.

Alternatively, the intermediate group Gm consists of a group of moving lenses having four negative refractive powers, and the subsequent group Gs includes the aperture stop St and is fixed with respect to the image plane Sim at the time of scaling. It can be configured to consist of a lens group having. In this case, it becomes easy to suppress fluctuations in various aberrations during miniaturization, high magnification, and variable magnification. In particular, it is advantageous in suppressing fluctuations in curvature of field and fluctuations in spherical aberration during scaling.

Any combination of the above-mentioned preferable configurations and possible configurations is possible, and it is preferable that they are appropriately selectively adopted according to the required specifications. According to the technique of the present disclosure, it is possible to realize a zoom lens having high optical performance by satisfactorily suppressing fluctuations in axial chromatic aberration from the wide-angle end to the zoom intermediate region while achieving miniaturization.

Next, numerical examples of the zoom lens of the present invention will be described.
[Example 1]
A cross-sectional view showing the configuration of the zoom lens of the first embodiment is shown in FIG. 1, and the method and configuration thereof are as described above. Therefore, a part of the duplication description will be omitted here. The zoom lens of the first embodiment has a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a negative refractive power in this order from the object side to the image side. It is composed of a third lens group G3 and a fourth lens group G4 having a positive refractive power. The intermediate group Gm includes a second lens group G2 and a third lens group G3. The subsequent group Gs is composed of the fourth lens group G4. At the time of scaling, the first lens group G1 and the fourth lens group G4 are fixed to the image plane Sim, and the second lens group G2 and the third lens group G3 are of adjacent lens groups. It moves along the optical axis Z by changing the interval.

The first lens group G1 is composed of 11 lenses L1a to L1k in order from the object side to the image side. The second lens group G2 is composed of six lenses L2a to L2f in order from the object side to the image side. The third lens group G3 is composed of two lenses L3a to L3b in order from the object side to the image side. The fourth lens group G4 is composed of an aperture diaphragm St and nine lenses L4a to L4i in this order from the object side to the image side. The lens L4a corresponds to the LA lens LA. The lens L4g and the lens L4i correspond to the LB lens LB. The lens L2d corresponds to the LN lens LN. The focus group consists of the lens L1e.

The basic lens data of the zoom lens of Example 1 is shown in Tables 1A and 1B, the specifications and variable surface spacing are shown in Table 2, and the aspherical coefficient is shown in Table 3. In addition, Table 1A and Table 1B show the basic lens data divided into two tables in order to avoid lengthening one table. In Tables 1A and 1B, the Sn column shows the surface number when the surface on the object side is the first surface and the number is increased by one toward the image side, and the R column shows the surface number of each surface. The radius of curvature is shown, and the column D shows the distance between each surface and the surface adjacent to the image side on the optical axis. Further, the column of Nd shows the refractive index of each component with respect to the d line, the column of νd shows the Abbe number based on the d line of each component, and the column of θgF shows the g line and F of each component. The partial dispersion ratio between the lines is shown.

In Tables 1A and 1B, the sign of the radius of curvature of the surface having the convex surface facing the object side is positive, and the sign of the radius of curvature of the surface having the convex surface facing the image side is negative. Table 1B also shows the aperture stop St and the optical member PP, and the surface number and the phrase (St) are described in the column of the surface number of the surface corresponding to the aperture stop St. The value in the bottom column of D in Table 1B is the distance between the most image-side surface and the image surface Sim in the table. In Tables 1A and 1B, the symbol DD [] is used for the variable surface spacing at the time of scaling, and the surface number of the object side of this spacing is added in [] and entered in the column D. ..

Table 2 shows the zoom magnification Zr, the focal length f, and the F number FNo. , Maximum total angle of view 2ω, and variable surface spacing are shown on a d-line basis. (°) in the column of 2ω means that the unit is degree. In Table 2, the values of the wide-angle end state, the intermediate focal length state, and the telephoto end state are shown in the columns labeled as the wide-angle end, the intermediate, and the telephoto end, respectively.

In Tables 1A and 1B, the surface numbers of the aspherical surface are marked with *, and the numerical value of the radius of curvature of the near axis is described in the column of the radius of curvature of the aspherical surface. In Table 3, the surface number of the aspherical surface is shown in the Sn column, and the numerical value of the aspherical coefficient for each aspherical surface is shown in the columns of KA and Am (m is an integer of 3 or more). The numerical value "E ± n" (n: integer) of the aspherical coefficient in Table 3 means "× 10 ^{± n} ". KA and Am are aspherical coefficients in the aspherical expression represented by the following equation.
Zd = C × h ² / {1+ (1-KA × C ² × h ² ) ^1/2 } + ΣAm × h ^m
However,
Zd: Aspherical depth (length of a perpendicular line drawn from a point on the aspherical surface at height h to a plane perpendicular to the optical axis where the aspherical apex touches)
h: Height (distance from the optical axis to the lens surface)
C: The reciprocal of the radius of curvature of the near axis KA, Am: the aspherical coefficient, and the aspherical Σ means the sum with respect to m.

In the data in each table, degrees are used as the unit of angle and mm (millimeter) is used as the unit of length. Units can also be used. In addition, in each table shown below, numerical values rounded to a predetermined digit are listed.

FIG. 8 shows each aberration diagram in a state where the zoom lens of the first embodiment is in focus on an infinity object. In FIG. 8, spherical aberration, astigmatism, distortion, and chromatic aberration of magnification are shown in order from the left. In FIG. 8, the upper part with the wide-angle end shows the one with the wide-angle end state, the middle part with the middle part shows the one with the intermediate focal length state, and the lower part with the telephoto end shows the one with the telephoto end state. In the spherical aberration diagram, the aberrations on the d-line, C-line, F-line, and g-line are shown by solid lines, long dashed lines, short dashed lines, and alternate long and short dash lines, respectively. In the astigmatism diagram, the aberration on the d-line in the sagittal direction is shown by a solid line, and the aberration on the d-line in the tangential direction is shown by a short dashed line. In the distortion diagram, the aberration on the d line is shown by a solid line. In the chromatic aberration of magnification diagram, the aberrations at the C line, the F line, and the g line are shown by a long dashed line, a short dashed line, and a two-dot chain line, respectively. FNo. Of the spherical aberration diagram. Means F number, and ω in other aberration diagrams means half angle of view.

Unless otherwise specified, the symbols, meanings, description methods, and illustration methods of the data related to the first embodiment are the same in the following examples, and thus duplicate description will be omitted below.

[Example 2]
A cross-sectional view showing the configuration of the zoom lens of the second embodiment is shown in FIG. The zoom lens of the second embodiment has a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a negative refractive power in this order from the object side to the image side. It is composed of a third lens group G3, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a negative refractive power. The intermediate group Gm includes a second lens group G2, a third lens group G3, and a fourth lens group G4. The subsequent group Gs is composed of the fifth lens group G5. At the time of scaling, the first lens group G1 and the fifth lens group G5 are fixed to the image plane Sim, and the second lens group G2, the third lens group G3, and the fourth lens group G4 Moves along the optical axis Z by changing the distance between adjacent lens groups.

The first lens group G1 is composed of five lenses L1a to L1e in order from the object side to the image side. The second lens group G2 is composed of one lens of the lens L2a. The third lens group G3 is composed of five lenses L3a to L3e in order from the object side to the image side. The fourth lens group G4 is composed of three lenses L4a to L4c in order from the object side to the image side. The fifth lens group G5 is composed of an aperture diaphragm St and 13 lenses of lenses L5a to L5m in this order from the object side to the image side. The lens L5a corresponds to the LA lens LA. The lens L5d, the lens L5k, and the lens L5m correspond to the LB lens LB. The lens L3b corresponds to the LN lens LN. The focus group consists of lenses L1c to L1e. The anti-vibration group consists of lenses L5f to L5g.

The basic lens data of the zoom lens of Example 2 is shown in Tables 4A and 4B, the specifications and variable surface spacing are shown in Table 5, the aspherical coefficient is shown in Table 6, and each aberration diagram in the state of being in focus on an infinite object is shown. It is shown in FIG.

[Example 3]
A cross-sectional view showing the configuration of the zoom lens of the third embodiment is shown in FIG. The zoom lens of Example 3 has a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a negative refractive power in this order from the object side to the image side. It is composed of a third lens group G3, a fourth lens group G4 having a negative refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power. The intermediate group Gm includes a second lens group G2, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. The subsequent group Gs consists of the sixth lens group G6. At the time of scaling, the first lens group G1 and the sixth lens group G6 are fixed to the image plane Sim, and the second lens group G2, the third lens group G3, and the fourth lens group G4 The fifth lens group G5 moves along the optical axis Z by changing the distance between adjacent lens groups.

The first lens group G1 is composed of five lenses L1a to L1e in order from the object side to the image side. The second lens group G2 is composed of one lens of the lens L2a. The third lens group G3 is composed of four lenses L3a to L3d in order from the object side to the image side. The fourth lens group G4 is composed of two lenses L4a to L4b in order from the object side to the image side. The fifth lens group G5 is composed of two lenses L5a to L5b in order from the object side to the image side. The sixth lens group G6 is composed of an aperture diaphragm St and ten lenses L6a to L6j in this order from the object side to the image side. The lens L6a corresponds to the LA lens LA. The lens L6b and the lens L6h correspond to the LB lens LB. The lens L4a corresponds to the LN lens LN. The focus group consists of lenses L1c to L1e. The anti-vibration group consists of lenses L6d to L6e.

Table 7 shows the basic lens data of the zoom lens of Example 3, Table 8 shows the specifications and variable surface spacing, Table 9 shows the aspherical coefficient, and FIG. 10 shows each aberration diagram in the state of being in focus on an infinite object. show.

[Example 4]
A cross-sectional view showing the configuration of the zoom lens of the fourth embodiment is shown in FIG. The zoom lens of the fourth embodiment has a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a negative refractive power in this order from the object side to the image side. It is composed of a third lens group G3, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a positive refractive power. The intermediate group Gm includes a second lens group G2 and a third lens group G3. The subsequent group Gs includes a fourth lens group G4 and a fifth lens group G5. At the time of scaling, the first lens group G1 and the fifth lens group G5 are fixed to the image plane Sim, and the second lens group G2, the third lens group G3, and the fourth lens group G4 Moves along the optical axis Z by changing the distance between adjacent lens groups.

The first lens group G1 is composed of six lenses L1a to L1f in order from the object side to the image side. The second lens group G2 is composed of six lenses L2a to L2f in order from the object side to the image side. The third lens group G3 is composed of two lenses L3a to L3b in order from the object side to the image side. The fourth lens group G4 is composed of an aperture diaphragm St and four lenses L4a to L4d in this order from the object side to the image side. The fifth lens group G5 is composed of six lenses L5a to L5f in order from the object side to the image side. The lens L4b corresponds to the LA lens LA. The lens L5b corresponds to the LB lens LB. The first focus group is composed of lenses L1d to L1e, the second focus group is composed of lenses L1f, and the optical axis Z is such that the first focus group and the second focus group have different trajectories during focusing. Move along.

The basic lens data of the zoom lens of Example 4 is shown in Table 10, the specifications and variable surface spacing are shown in Table 11, the aspherical coefficient is shown in Table 12, and the aberration diagrams in the state of being in focus on an infinite object are shown in FIG. show.

[Example 5]
A cross-sectional view showing the configuration of the zoom lens of the fifth embodiment is shown in FIG. The zoom lens of Example 5 has a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a negative refractive power in this order from the object side to the image side. It is composed of a third lens group G3 and a fourth lens group G4 having a positive refractive power. The intermediate group Gm includes a second lens group G2 and a third lens group G3. The succeeding group Gs is composed of the fourth lens group G4. At the time of scaling, the first lens group G1 and the fourth lens group G4 are fixed to the image plane Sim, and the second lens group G2 and the third lens group G3 are of adjacent lens groups. It moves along the optical axis Z by changing the interval.

The first lens group G1 is composed of eight lenses L1a to L1h in order from the object side to the image side. The second lens group G2 is composed of four lenses L2a to L2d in order from the object side to the image side. The third lens group G3 is composed of two lenses L3a to L3b in order from the object side to the image side. The fourth lens group G4 is composed of an aperture diaphragm St and nine lenses L4a to L4i in this order from the object side to the image side. The lens L4f corresponds to the LA lens LA. The lens L4g corresponds to the LB lens LB. The focus group consists of lenses L1d to L1e.

The basic lens data of the zoom lens of Example 5 is shown in Table 13, the specifications and variable surface spacing are shown in Table 14, the aspherical coefficient is shown in Table 15, and the aberration diagrams in the state of being in focus on an infinite object are shown in FIG. show.

[Example 6]
A cross-sectional view showing the configuration of the zoom lens of the sixth embodiment is shown in FIG. The zoom lens of Example 6 has a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a negative refractive power in this order from the object side to the image side. It is composed of a third lens group G3, a fourth lens group G4 having a negative refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power. The intermediate group Gm includes a second lens group G2, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. The subsequent group Gs consists of the sixth lens group G6. At the time of scaling, the first lens group G1 and the sixth lens group G6 are fixed to the image plane Sim, and the second lens group G2, the third lens group G3, and the fourth lens group G4 The fifth lens group G5 moves along the optical axis Z by changing the distance between adjacent lens groups.

The first lens group G1 is composed of five lenses L1a to L1e in order from the object side to the image side. The second lens group G2 is composed of one lens of the lens L2a. The third lens group G3 is composed of four lenses L3a to L3d in order from the object side to the image side. The fourth lens group G4 is composed of two lenses L4a to L4b in order from the object side to the image side. The fifth lens group G5 is composed of two lenses L5a to L5b in order from the object side to the image side. The sixth lens group G6 is composed of an aperture diaphragm St and 12 lenses L6a to L6l in this order from the object side to the image side. The lens L6a corresponds to the LA lens LA. The lens L6b and the lens L6c correspond to the LB lens LB. The lens L4a corresponds to the LN lens LN. The focus group consists of lenses L1c to L1e. The anti-vibration group consists of lenses L6e to L6f.

The basic lens data of the zoom lens of Example 6 is shown in Tables 16A and 16B, the specifications and variable surface spacing are shown in Table 17, the aspherical coefficient is shown in Table 18, and each aberration diagram in the state of being in focus on an infinite object is shown. It is shown in FIG.

Table 19 shows the corresponding values of the conditional expressions (1) to (12) of the zoom lenses of Examples 1 to 6. Examples 1 to 6 are based on the d line. Table 19 shows the values based on the d-line. The code of the corresponding LB lens LB is written in parentheses below the corresponding values of the conditional expressions (6) and (7).

As can be seen from the above data, the zoom lenses of Examples 1 to 6 have been miniaturized, have a magnification of 5 times or more, have a relatively high magnification, and fluctuate axial chromatic aberration from the wide-angle end to the zoom intermediate range. Is well suppressed to achieve high optical performance.

Next, the image pickup apparatus according to the embodiment of the present invention will be described. FIG. 14 shows a schematic configuration diagram of an image pickup device 100 using the zoom lens 1 according to the embodiment of the present invention as an example of the image pickup device according to the embodiment of the present invention. Examples of the image pickup apparatus 100 include a broadcasting camera, a movie shooting camera, a video camera, a surveillance camera, and the like.

The image pickup device 100 includes a zoom lens 1, a filter 2 arranged on the image side of the zoom lens 1, and an image pickup element 3 arranged on the image side of the filter 2. Note that FIG. 14 schematically illustrates a plurality of lenses included in the zoom lens 1.

The image sensor 3 converts an optical image formed by the zoom lens 1 into an electric signal, and for example, a CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), or the like can be used. The image pickup device 3 is arranged so that its image pickup surface coincides with the image plane of the zoom lens 1.

The image pickup device 100 also has a signal processing unit 5 that calculates and processes an output signal from the image pickup element 3, a display unit 6 that displays an image formed by the signal processing unit 5, and a change that controls the scaling of the zoom lens 1. A double control unit 7 is provided. Although only one image sensor 3 is shown in FIG. 14, a so-called three-plate image sensor having three image sensors may be used.

Although the techniques of the present disclosure have been described above with reference to the embodiments and examples, the techniques of the present disclosure are not limited to the above-described embodiments and examples, and various modifications are possible. For example, the radius of curvature, the interplanar spacing, the refractive index, the Abbe number, the aspherical coefficient, and the like of each lens are not limited to the values shown in the above numerical examples, and may take other values.

1 Zoom lens 2 Filter 3 Imaging element 5 Signal processing unit 6 Display unit 7 Variable magnification control unit 100 Imaging device G1 1st lens group G2 2nd lens group G3 3rd lens group G4 4th lens group G5 5th lens group G6 6 Lens group Gm Intermediate group Gs Subsequent group L1a to L6l Lens LA LA lens LB LB lens LN LN lens ma, ta, wa Axial light beam mb, tb, wb Maximum angle of light beam PP Optical member Sim Image plane St Aperture aperture Z optical axis

Claims (18)

In order from the object side to the image side, the distance between the first lens group having a positive refractive power fixed to the image plane at the time of scaling and the adjacent group at the time of scaling is changed. It consists of an intermediate group consisting of two or more moving lens groups that move along the optical axis, and a subsequent group that has a lens group including an aperture on the object side most.
At least two of the moving lens groups in the intermediate group have a negative refractive power and
The trailing group comprises at least one positive lens, the LA lens.
The refractive index of the LA lens on the d line is NdA,
The Abbe number based on the d-line of the LA lens is νdA,
When the partial dispersion ratio between the g-line and the F-line of the LA lens is θgFA,
The LA lens has 1.72 <NdA <1.84 (1).
43 <νdA <57 (2)
0.637 <θgFA + 0.001625 × νdA < 0.65 (3 -1)
2.21 <NdA + 0.01 × νdA (4)
A zoom lens that satisfies the conditional expressions (1), (2), ( 3-1 ), and (4) represented by. The subsequent group includes at least one LA lens on the image side of the aperture.
When the LA lens located closest to the object side of the LA lenses on the image side of the aperture is used as the LA lens on the most object side.
The distance between the aperture and the LA lens on the most object side on the optical axis at the wide-angle end is LDW.
When the distance on the optical axis between the aperture and the lens surface on the image side at the wide-angle end is SDW.
0.005 <LDW / SDW <0.45 (5)
The zoom lens according to claim 1, which satisfies the conditional expression (5) represented by. The subsequent group includes an LB lens which is at least one positive lens on the image side of the LA lens on the most object side.
The Abbe number based on the d-line of the LB lens is ν dB,
When the partial dispersion ratio between the g-line and the F-line of the LB lens is θgFB,
The LB lens has 65 <ν dB <105 (6).
0.6355 <θgFB + 0.001625 × νdB <0.7 (7)
The zoom lens according to claim 2, which satisfies the conditional expressions (6) and (7) represented by. The focal length of the LA lens on the most object side is fA,
The total number of the LB lenses arranged on the image side of the most object side LA lens is k.
The LB lenses arranged on the image side of the LA lens on the most object side are numbered in order from the object side, i.
When the focal length of the i-th LB lens from the object side is fBi among the LB lenses arranged on the image side of the LA lens on the most object side.

The zoom lens according to claim 3, which satisfies the conditional expression (8) represented by. The zoom lens according to any one of claims 1 to 4, wherein the lens arranged closest to the object in the subsequent group is the LA lens. The zoom lens according to any one of claims 1 to 5, wherein the object-side surface of at least one LA lens included in the subsequent group is a convex surface. The zoom lens according to any one of claims 1 to 6, wherein focusing is performed by moving at least a part of the lenses in the first lens group along the optical axis. The zoom lens according to any one of claims 1 to 7, wherein the moving lens group on the most image side in the intermediate group has a negative refractive power. The intermediate group comprises the moving lens group having two negative refractive powers.
The zoom lens according to claim 8, wherein the subsequent group comprises a lens group having a positive refractive power that is fixed to the image plane at the time of scaling. The intermediate group comprises the moving lens group having two negative refractive powers.
The subsequent group is a lens group having a positive refractive power that moves along the optical axis by changing the distance between adjacent groups at the time of scaling in order from the object side to the image side, and the variable magnification. The zoom lens according to claim 8, which comprises a lens group having a positive refractive power fixed to the image plane. The intermediate group comprises the moving lens group having three negative refractive powers.
The zoom lens according to claim 8, wherein the subsequent group comprises a lens group having a refractive power fixed to the image plane at the time of scaling. The intermediate group comprises the moving lens group having four negative refractive powers.
The zoom lens according to claim 8, wherein the subsequent group comprises a lens group having a positive refractive power that is fixed to the image plane at the time of scaling. The moving lens group having at least one negative refractive power in the intermediate group includes at least one negative lens, an LN lens.
The refractive index of the LN lens on the d line is Ndn,
The Abbe number based on the d-line of the LN lens is νdn,
When the partial dispersion ratio between the g-line and the F-line of the LN lens is θgFn,
The LN lens has 1.72 <Ndn <1.8 (9).
43 <νdn <57 (10)
0.6355 <θgFn + 0.001625 × νdn <0.66 (11)
2.21 <Ndn + 0.01 × νdn (12)
The zoom lens according to any one of claims 1 to 12, which satisfies the conditional expressions (9), (10), (11), and (12) represented by. The LA lens is further increased by 45 <νdA <55 (2-1).
The zoom lens according to any one of claims 1 to 13, which satisfies the conditional expression (2-1) represented by. The LA lens further adds 2.21 <NdA + 0.01 × νdA <2.33 (4-1).
The zoom lens according to any one of claims 1 to 14 , which satisfies the conditional expression (4-1) represented by. 0.005 <LDW / SDW <0.2 (5-1)
The zoom lens according to claim 2, which satisfies the conditional expression (5-1) represented by.

The zoom lens according to claim 4, which satisfies the conditional expression (8-1) represented by. An imaging device including the zoom lens according to any one of claims 1 to 17.

Images