WO2013027362A1

WO2013027362A1 - Zoom lens system, interchangeable lens device, and camera system

Info

Publication number: WO2013027362A1
Application number: PCT/JP2012/005098
Authority: WO
Inventors: 俊一郎吉永; 恭一宮崎
Original assignee: パナソニック株式会社
Priority date: 2011-08-25
Filing date: 2012-08-10
Publication date: 2013-02-28

Abstract

A zoom lens system provided with a first lens group having a negative power, a second lens group having a positive power, and a rear lens group comprising at least one lens group, wherein the zooming operation is performed by changing the distance between each lens group, and at least two lens elements among all the lens elements constituting the second lens group satisfies the following conditions: 0.660327≤{(ng-nF)+0.001802×(nd-1)}/(nF-nC)≤0.730327 and (nd-1)/(nF-nC)≥50 (wherein ng, nF, nd, and nC respectively represents the refractive index of the g line, F line, d line, and C line of the lens elements constituting the second lens group).

Description

Zoom lens system, interchangeable lens device and camera system

The present disclosure relates to a zoom lens system, an interchangeable lens device, and a camera system.

The interchangeable-lens digital camera system (hereinafter also simply referred to as “camera system”) can shoot high-quality images with high sensitivity, and has high-speed focusing and post-shooting image processing. There is an advantage that the interchangeable lens device can be easily replaced, and it has been rapidly spread in recent years. In addition, an interchangeable lens device including a zoom lens system that forms an optical image so as to be variable in magnification is popular in that the focal length can be freely changed without exchanging lenses.

Various zoom lens systems having high optical performance from the wide-angle end to the telephoto end have been proposed as zoom lens systems used for interchangeable lens devices.

Patent Document 1 discloses a projection lens in which, among at least two moving lens groups that move at the time of zooming, the maximum moving lens group that has the maximum movement amount has at least one positive lens.

Patent Document 2 discloses a zoom lens having a first lens group having a negative power and a second lens group having a positive power, and the first lens group having a composite optical element including a lens element and a resin layer laminated thereon. Is disclosed.

JP 2010-008797 A JP 2007-155836 A

The present disclosure provides a zoom lens system that has a short overall lens length, is small and lightweight, and is particularly excellent in optical performance with sufficiently corrected chromatic aberration. The present disclosure also provides an interchangeable lens apparatus and a camera system including the zoom lens system.

The zoom lens system in the present disclosure is:
Having a plurality of lens groups composed of at least one lens element;
From the object side to the image side,
A first lens group having negative power;
A second lens group having positive power;
A rear lens group comprising at least one lens group,
Zooming from the wide-angle end to the telephoto end during imaging by changing the interval on the optical axis of each lens group,
Of all the lens elements constituting the second lens group, at least two lenses satisfy the following conditions (1) and (2):
0.660327 ≦ {(ng−nF) + 0.001802 × (nd−1)} / (nF−nC) ≦ 0.730327 (1)
(Nd-1) / (nF-nC) ≧ 50 (2)
(here,
ng: refractive index with respect to g-line (wavelength: 435.84 nm) of the lens elements constituting the second lens group,
nF: refractive index with respect to F-line (wavelength: 486.13 nm) of the lens elements constituting the second lens group,
nd: refractive index with respect to d-line (wavelength: 587.56 nm) of lens elements constituting the second lens group;
nC: Refractive index with respect to C line (wavelength: 656.27 nm) of the lens elements constituting the second lens group)
Satisfied.

The interchangeable lens device in the present disclosure is:
Having a plurality of lens groups composed of at least one lens element;
From the object side to the image side,
A first lens group having negative power;
A second lens group having positive power;
A rear lens group comprising at least one lens group,
Zooming from the wide-angle end to the telephoto end during imaging by changing the interval on the optical axis of each lens group,
Of all the lens elements constituting the second lens group, at least two lenses satisfy the following conditions (1) and (2):
0.660327 ≦ {(ng−nF) + 0.001802 × (nd−1)} / (nF−nC) ≦ 0.730327 (1)
(Nd-1) / (nF-nC) ≧ 50 (2)
(here,
ng: refractive index with respect to g-line of lens elements constituting the second lens group,
nF: refractive index with respect to the F line of the lens elements constituting the second lens group,
nd: refractive index with respect to d-line of lens elements constituting the second lens group,
nC: Refractive index with respect to the C line of the lens elements constituting the second lens group)
Zoom lens system that satisfies
A lens mount unit that can be connected to a camera body including an image sensor that receives an optical image formed by the zoom lens system and converts the optical image into an electrical image signal.

The camera system in the present disclosure is:
Having a plurality of lens groups composed of at least one lens element;
From the object side to the image side,
A first lens group having negative power;
A second lens group having positive power;
A rear lens group comprising at least one lens group,
Zooming from the wide-angle end to the telephoto end during imaging by changing the interval on the optical axis of each lens group,
Of all the lens elements constituting the second lens group, at least two lenses satisfy the following conditions (1) and (2):
0.660327 ≦ {(ng−nF) + 0.001802 × (nd−1)} / (nF−nC) ≦ 0.730327 (1)
(Nd-1) / (nF-nC) ≧ 50 (2)
(here,
ng: refractive index with respect to g-line of lens elements constituting the second lens group,
nF: refractive index with respect to the F line of the lens elements constituting the second lens group,
nd: refractive index with respect to d-line of lens elements constituting the second lens group,
nC: Refractive index with respect to the C line of the lens elements constituting the second lens group)
An interchangeable lens apparatus including a zoom lens system satisfying
And a camera body including an image sensor that receives the optical image formed by the zoom lens system and converts the optical image into an electrical image signal.

The zoom lens system according to the present disclosure has a short overall lens length, is small and lightweight, and is particularly excellent in optical performance because chromatic aberration is sufficiently corrected.

FIG. 1 is a lens arrangement diagram illustrating an infinitely focused state of the zoom lens system according to Embodiment 1 (Numerical Example 1). FIG. 2 is a longitudinal aberration diagram of the zoom lens system according to Numerical Example 1 when the zoom lens system is in focus at infinity. FIG. 3 is a lateral aberration diagram in a basic state where image blur correction is not performed and in an image blur correction state at the telephoto end of the zoom lens system according to Numerical Example 1. FIG. 4 is a lens arrangement diagram illustrating an infinitely focused state of the zoom lens system according to Embodiment 2 (Numerical Example 2). FIG. 5 is a longitudinal aberration diagram of the zoom lens system according to Numerical Example 2 when the zoom lens system is in focus at infinity. 6 is a lateral aberration diagram in a basic state where image blur correction is not performed and in an image blur correction state at the telephoto end of a zoom lens system according to Numerical Example 2. FIG. FIG. 7 is a lens layout diagram illustrating an infinitely focused state of the zoom lens system according to Embodiment 3 (Numerical Example 3). FIG. 8 is a longitudinal aberration diagram of the zoom lens system according to Numerical Example 3 when the zoom lens system is in focus at infinity. FIG. 9 is a lateral aberration diagram in a basic state where image blur correction is not performed and in an image blur correction state at the telephoto end of a zoom lens system according to Numerical Example 3. FIG. 10 is a lens arrangement diagram illustrating an infinitely focused state of the zoom lens system according to Embodiment 4 (Numerical Example 4). FIG. 11 is a longitudinal aberration diagram of the zoom lens system according to Numerical Example 4 when the zoom lens system is in focus at infinity. 12 is a lateral aberration diagram in a basic state where image blur correction is not performed and in an image blur correction state at the telephoto end of a zoom lens system according to Numerical Example 4. FIG. FIG. 13 is a schematic configuration diagram of an interchangeable lens digital camera system according to the fifth embodiment.

Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

In addition, the inventors provide the accompanying drawings and the following description in order for those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims. Absent.

(Embodiments 1 to 4)
1, 4, 7, and 10 are lens arrangement diagrams of the zoom lens systems according to Embodiments 1 to 4, respectively, and all represent the zoom lens system in an infinitely focused state.

In each figure, (a) shows a lens configuration at the wide angle end (shortest focal length state: focal length f _W ), and (b) shows an intermediate position (intermediate focal length state: focal length f _M = √ (f _W * f). The lens configuration of _T )) and (c) show the lens configuration at the telephoto end (longest focal length state: focal length f _T ). Also, in each figure, the broken line arrows provided between FIGS. (A) and (b) are obtained by connecting the positions of the lens groups in the wide-angle end, the intermediate position, and the telephoto end in order from the top. Straight line. The wide-angle end and the intermediate position, and the intermediate position and the telephoto end are simply connected by a straight line, which is different from the actual movement of each lens group.

Further, in each figure, an arrow attached to the lens group represents focusing from an infinitely focused state to a close object focused state. That is, FIGS. 1, 4, 7, and 10 show the direction in which a third lens group G3, which will be described later, moves during focusing from an infinite focus state to a close object focus state.

The zoom lens system according to Embodiment 1 includes, in order from the object side to the image side, a first lens group G1 having negative power, a second lens group G2 having positive power, and a first lens group having negative power. 3 lens group G3. In the zoom lens system according to Embodiment 1, during zooming, the distance between the lens groups, that is, the distance between the first lens group G1 and the second lens group G2, and the second lens group G2 and the third lens group G3. All the lens groups move in the direction along the optical axis so that the distance between them changes. In the zoom lens system according to Embodiment 1, by making these lens groups have a desired power arrangement, the entire lens system can be reduced in size while maintaining high optical performance.

In the zoom lens systems according to Embodiments 2 to 4, in order from the object side to the image side, the first lens group G1 having negative power, the second lens group G2 having positive power, and the negative power And a fourth lens group G4 having a positive power. In the zoom lens system according to Embodiment 2, during zooming, the distance between the lens groups, that is, the distance between the first lens group G1 and the second lens group G2, the second lens group G2 and the third lens group G3, The first lens group G1, the second lens group G2, and the third lens group G3 are in a direction along the optical axis so that the distance between the third lens group G3 and the fourth lens group G4 changes. Move to each. In the zoom lens systems according to Embodiments 3 and 4, during zooming, the distance between the lens groups, that is, the distance between the first lens group G1 and the second lens group G2, the second lens group G2 and the third lens group. All the lens groups are moved in the direction along the optical axis so that both the distance from G3 and the distance between the third lens group G3 and the fourth lens group G4 change. The zoom lens system according to each embodiment can reduce the size of the entire lens system while maintaining high optical performance by arranging these lens groups in a desired power arrangement.

In FIGS. 1, 4, 7, and 10, an asterisk * attached to a specific surface indicates that the surface is aspherical. In each figure, a symbol (+) and a symbol (−) attached to a symbol of each lens group correspond to a power symbol of each lens group. In each figure, the straight line described on the rightmost side represents the position of the image plane S.

As shown in FIGS. 1, 4, 7 and 10, an aperture stop A is provided between the fourth lens element L4 and the fifth lens element L5 in the second lens group G2.

(Embodiment 1)
As shown in FIG. 1, the first lens group G1 includes, in order from the object side to the image side, a negative meniscus first lens element L1 having a convex surface facing the object side, and a negative meniscus having a convex surface facing the object side. It comprises a second lens element L2 having a shape and a third lens element L3 having a positive meniscus shape with a convex surface facing the object side. Among these, the second lens element L2 has two aspheric surfaces.

The second lens group G2 includes, in order from the object side to the image side, a positive meniscus fourth lens element L4 with a convex surface facing the object side, and a negative meniscus fifth lens element L5 with a convex surface facing the object side. And a sixth lens element L6 having a biconvex shape and a seventh lens element L7 having a positive meniscus shape having a convex surface facing the object side. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented. The fourth lens element L4 has two aspheric surfaces, and the seventh lens element L7 has an aspheric image side surface. Furthermore, an aperture stop A is provided between the fourth lens element L4 and the fifth lens element L5. In the second lens group G2, the sixth lens element L6 and the seventh lens element L7 simultaneously satisfy conditions (1) and (2) described later.

The third lens group G3 includes only a biconcave eighth lens element L8. The eighth lens element L8 has two aspheric surfaces.

In the zoom lens system according to Embodiment 1, during zooming from the wide-angle end to the telephoto end during imaging, the first lens group G1 moves along a locus convex toward the image side, and the second lens group G2 Moves monotonously to the object side, and the third lens group G3 moves substantially monotonically to the object side. That is, during zooming, all the lens groups are placed on the optical axis so that the distance between the first lens group G1 and the second lens group G2 changes and the distance between the second lens group G2 and the third lens group G3 changes. Move along each.

Furthermore, in the zoom lens system according to Embodiment 1, the third lens group G3 is a focusing lens group that moves along the optical axis during focusing from an infinitely focused state to a close object focused state, The third lens group G3 moves toward the image side along the optical axis during focusing.

Further, by moving the seventh lens element L7 in the second lens group G2 in a direction orthogonal to the optical axis, image point movement due to vibration of the entire system is corrected, that is, image blur due to camera shake, vibration, or the like is corrected. It can be corrected optically.

(Embodiment 2)
As shown in FIG. 4, the first lens group G1 includes, in order from the object side to the image side, a negative meniscus first lens element L1 having a convex surface facing the object side, and a negative meniscus having a convex surface facing the object side. It comprises a second lens element L2 having a shape and a third lens element L3 having a positive meniscus shape with a convex surface facing the object side. Among these, the second lens element L2 has two aspheric surfaces.

The second lens group G2, in order from the object side to the image side, includes a biconvex fourth lens element L4, a biconcave fifth lens element L5, a biconvex sixth lens element L6, and an object. And a plano-convex seventh lens element L7 having a convex surface directed to the side. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented. The fourth lens element L4 has two aspheric surfaces. Furthermore, an aperture stop A is provided between the fourth lens element L4 and the fifth lens element L5. In the second lens group G2, the sixth lens element L6 and the seventh lens element L7 simultaneously satisfy conditions (1) and (2) described later.

The fourth lens group G4 comprises solely a biconvex ninth lens element L9. The ninth lens element L9 has two aspheric surfaces.

In the zoom lens system according to Embodiment 2, during zooming from the wide-angle end to the telephoto end during imaging, the first lens group G1 moves along a locus convex toward the image side, and the second lens group G2 Moves monotonously toward the object side, the third lens group G3 moves along a locus convex toward the object side, and the fourth lens group G4 is fixed with respect to the image plane S. That is, during zooming, the distance between the first lens group G1 and the second lens group G2 changes, the distance between the second lens group G2 and the third lens group G3 changes, and the third lens group G3 and the fourth lens. The first lens group G1, the second lens group G2, and the third lens group G3 move along the optical axis so that the distance from the group G4 changes.

Furthermore, in the zoom lens system according to Embodiment 2, the third lens group G3 is a focusing lens group that moves along the optical axis during focusing from an infinity in-focus state to a close object in-focus state, The third lens group G3 moves toward the image side along the optical axis during focusing.

(Embodiment 3)
As shown in FIG. 7, the first lens group G1 includes, in order from the object side to the image side, a negative meniscus first lens element L1 having a convex surface facing the object side, and a negative meniscus having a convex surface facing the object side. It comprises a second lens element L2 having a shape and a third lens element L3 having a positive meniscus shape with a convex surface facing the object side. Among these, the second lens element L2 has two aspheric surfaces.

The fourth lens group G4 comprises solely a positive meniscus ninth lens element L9 with the convex surface facing the object side. The ninth lens element L9 has two aspheric surfaces.

In the zoom lens system according to Embodiment 3, during zooming from the wide-angle end to the telephoto end during imaging, the first lens group G1 moves monotonously to the image side, and the second lens group G2 monotonously Moving to the object side, the third lens group G3 monotonously moves to the image side, and the fourth lens group G4 monotonously moves to the image side. That is, during zooming, the distance between the first lens group G1 and the second lens group G2 decreases, the distance between the second lens group G2 and the third lens group G3 increases, and the third lens group G3 and the fourth lens. All the lens groups move along the optical axis so that the distance from the group G4 changes.

In the zoom lens system according to Embodiment 3, the third lens group G3 is a focusing lens group that moves along an optical axis in focusing from an infinite focus state to a close object focus state, The third lens group G3 moves toward the image side along the optical axis during focusing.

(Embodiment 4)
As shown in FIG. 10, the first lens group G1 includes, in order from the object side to the image side, a negative meniscus first lens element L1 having a convex surface facing the object side, and a negative meniscus having a convex surface facing the image side. It comprises a second lens element L2 having a shape and a third lens element L3 having a positive meniscus shape with a convex surface facing the object side. Among these, the first lens element L1 has an aspheric image side surface, and the second lens element L2 has both aspheric surfaces.

The second lens group G2 includes, in order from the object side to the image side, a biconvex fourth lens element L4, a negative meniscus fifth lens element L5 with a convex surface facing the object side, and a biconvex second lens element L5. 6 lens elements L6 and a biconvex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented. The fourth lens element L4 has two aspheric surfaces. Furthermore, an aperture stop A is provided between the fourth lens element L4 and the fifth lens element L5. In the second lens group G2, the sixth lens element L6 and the seventh lens element L7 simultaneously satisfy conditions (1) and (2) described later.

The third lens group G3 comprises solely a negative meniscus eighth lens element L8 with the convex surface facing the object side. The eighth lens element L8 has two aspheric surfaces.

In the zoom lens system according to Embodiment 4, during zooming from the wide-angle end to the telephoto end during imaging, the first lens group G1 moves along a locus convex toward the image side, and the second lens group G2 Moves monotonously to the object side, the third lens group G3 monotonously moves to the object side, and the fourth lens group G4 monotonously moves to the image side. That is, during zooming, the distance between the first lens group G1 and the second lens group G2 changes, the distance between the second lens group G2 and the third lens group G3 changes, and the third lens group G3 and the fourth lens. All the lens groups move along the optical axis so that the distance from the group G4 increases.

Furthermore, in the zoom lens system according to Embodiment 4, the third lens group G3 is a focusing lens group that moves along an optical axis during focusing from an infinity in-focus state to a close object in-focus state, The third lens group G3 moves toward the image side along the optical axis during focusing.

As described above, Embodiments 1 to 4 have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can also be applied to an embodiment in which changes, replacements, additions, omissions, and the like are appropriately performed.

Hereinafter, for example, conditions useful for satisfying a zoom lens system such as the zoom lens systems according to Embodiments 1 to 4 will be described. A plurality of useful conditions are defined for the zoom lens system according to each embodiment, but the configuration of the zoom lens system that satisfies all of the plurality of conditions is most useful. However, by satisfying individual conditions, it is possible to obtain a zoom lens system that exhibits the corresponding effects.

For example, as in the zoom lens systems according to Embodiments 1 to 4, the first lens has a plurality of lens groups each including at least one lens element, and has negative power in order from the object side to the image side. Group, a second lens group having a positive power, and a rear lens group composed of at least one lens group, and changing the distance on the optical axis of each lens group from the wide-angle end to the telephoto end during imaging In a zoom lens system that performs zooming (hereinafter, this lens configuration is referred to as a basic configuration of the embodiment), at least two of all lens elements constituting the second lens group must satisfy the following condition (1) and Satisfy (2).
0.660327 ≦ {(ng−nF) + 0.001802 × (nd−1)} / (nF−nC) ≦ 0.730327 (1)
(Nd-1) / (nF-nC) ≧ 50 (2)
here,
ng: refractive index with respect to g-line of lens elements constituting the second lens group,
nF: refractive index with respect to the F line of the lens elements constituting the second lens group,
nd: refractive index with respect to d-line of lens elements constituting the second lens group,
nC is the refractive index with respect to the C line of the lens elements constituting the second lens group.

The conditions (1) and (2) are conditions for defining partial dispersion of lens elements constituting the second lens group. If either one of the conditions (1) and (2) is not satisfied, it is difficult to correct chromatic aberration generated in the second lens group, and excellent optical performance cannot be ensured.

In addition, the said effect can be made more successful by satisfy | filling at least 1 of the following conditions (1) 'and (2)'.
0.660327 ≦ {(ng−nF) + 0.001802 × (nd−1)} / (nF−nC) ≦ 0.710327 (1) ′
(Nd-1) / (nF-nC) ≧ 60 (2) ′

Furthermore, by satisfying at least one of the following conditions (1) ″ and (2) ″, the above effect can be further achieved.
0.660327 ≦ {(ng−nF) + 0.001802 × (nd−1)} / (nF−nC) ≦ 0.690327 (1) ″
(Nd-1) / (nF-nC) ≧ 65 (2) ''

For example, as in the zoom lens systems according to Embodiments 1 to 4, it has a basic configuration, and at least two of all the lens elements constituting the second lens group satisfy the conditions (1) and (2). It is beneficial for the zoom lens system to satisfy the following condition (3).
1.3 ≦ M ≦ 5.0 (3)
here,
M: imaging magnification at the d-line of the rear lens group at the telephoto end.

The condition (3) is a condition that defines the imaging magnification of the rear lens group. If the lower limit of the condition (3) is not reached, the focal lengths of the first lens group and the second lens group become longer, and the first lens group and the second lens group become larger, making it difficult to reduce the size of the zoom lens system. It becomes. On the contrary, if the upper limit of the condition (3) is exceeded, the aberration generated in the first lens group and the second lens group is excessively enlarged, and there is a possibility that excellent optical performance cannot be ensured.

It should be noted that the above effect can be further achieved by satisfying at least one of the following conditions (3-1) ′ and (3-1) ″.
1.4 ≦ M (3-1) ′
M ≦ 3.0 (3-1) ''

Furthermore, the above effect can be further achieved by satisfying at least one of the following conditions (3-2) ′ and (3-2) ″.
1.5 ≦ M (3-2) ′
M ≦ 2.0 (3-2) ''

Each lens group constituting the zoom lens system according to Embodiments 1 to 4 includes a refractive lens element that deflects incident light by refraction (that is, a type in which deflection is performed at an interface between media having different refractive indexes) However, the present invention is not limited to this. For example, a diffractive lens element that deflects incident light by diffraction, a refractive / diffractive hybrid lens element that deflects incident light by a combination of diffractive action and refractive action, and a refractive index that deflects incident light according to the refractive index distribution in the medium Each lens group may be composed of a distributed lens element or the like. In particular, in a refractive / diffractive hybrid lens element, forming a diffractive structure at the interface of media having different refractive indexes is advantageous because the wavelength dependency of diffraction efficiency is improved.

(Embodiment 5)
FIG. 9 is a schematic configuration diagram of an interchangeable lens digital camera system according to the fifth embodiment.

The interchangeable lens digital camera system 100 according to the fifth embodiment includes a camera body 101 and an interchangeable lens apparatus 201 that is detachably connected to the camera body 101.

The camera body 101 receives an optical image formed by the zoom lens system 202 of the interchangeable lens apparatus 201 and converts it into an electrical image signal, and displays the image signal converted by the image sensor 102. A liquid crystal monitor 103 and a camera mount unit 104 are included. On the other hand, the interchangeable lens device 201 includes a zoom lens system 202 according to any of Embodiments 1 to 4, a lens barrel 203 that holds the zoom lens system 202, and a lens mount unit connected to the camera mount unit 104 of the camera body. 204. The camera mount unit 104 and the lens mount unit 204 electrically connect not only a physical connection but also a controller (not shown) in the camera body 101 and a controller (not shown) in the interchangeable lens device 201. It also functions as an interface that enables mutual signal exchange. Note that FIG. 9 illustrates a case where the zoom lens system according to Embodiment 1 is used as the zoom lens system 202.

In the fifth embodiment, since the zoom lens system 202 according to any one of the first to fourth embodiments is used, an interchangeable lens apparatus that is compact and excellent in imaging performance can be realized at low cost. Further, it is possible to reduce the size and cost of the entire camera system 100 according to the fifth embodiment. Note that the zoom lens systems according to Embodiments 1 to 4 do not have to use the entire zooming area. That is, a range in which the optical performance is ensured according to a desired zooming region may be cut out and used as a zoom lens system having a lower magnification than the zoom lens system described in the corresponding numerical examples 1 to 4 below. Good.

As described above, the fifth embodiment has been described as an example of the technique disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can also be applied to an embodiment in which changes, replacements, additions, omissions, and the like are appropriately performed.

Hereinafter, numerical examples in which the zoom lens systems according to Embodiments 1 to 4 are specifically implemented will be described. In each numerical example, the unit of length in the table is “mm”, and the unit of angle of view is “°”. In each numerical example, r is a radius of curvature, d is a surface interval, nd is a refractive index with respect to the d line, and νd is an Abbe number with respect to the d line. In each numerical example, the surface marked with * is an aspherical surface, and the aspherical shape is defined by the following equation.

here,
Z: distance from a point on the aspheric surface having a height h from the optical axis to the tangent plane of the aspheric vertex,
h: height from the optical axis,
r: vertex radius of curvature,
κ: conic constant,
An: n-order aspherical coefficient.

2, 5, 8 and 11 are longitudinal aberration diagrams of the zoom lens system according to Numerical Examples 1 to 4 in an infinitely focused state, respectively.

In each longitudinal aberration diagram, (a) shows the aberration at the wide angle end, (b) shows the intermediate position, and (c) shows the aberration at the telephoto end. Each longitudinal aberration diagram shows spherical aberration (SA (mm)), astigmatism (AST (mm)), and distortion (DIS (%)) in order from the left side. In the spherical aberration diagram, the vertical axis represents the F number (indicated by F in the figure), the solid line is the d line (d-line), the short broken line is the F line (F-line), and the long broken line is the C line (C- line) and the dashed line are the characteristics of the g-line. In the astigmatism diagram, the vertical axis represents the image height (indicated by H in the figure), the solid line represents the sagittal plane (indicated by s), and the broken line represents the meridional plane (indicated by m in the figure). is there. In the distortion diagram, the vertical axis represents the image height (indicated by H in the figure).

FIGS. 3, 6, 9 and 12 are lateral aberration diagrams at the telephoto end of the zoom lens systems according to Numerical Examples 1 to 4, respectively.

In each lateral aberration diagram, the upper three aberration diagrams show the basic state where image blur correction is not performed at the telephoto end, and the lower three aberration diagrams show the seventh lens element L7 in the second lens group G2 perpendicular to the optical axis. This corresponds to the image blur correction state at the telephoto end moved by a predetermined amount in a certain direction. Of the lateral aberration diagrams in the basic state, the upper row shows the lateral aberration at the image point of 70% of the maximum image height, the middle row shows the lateral aberration at the axial image point, and the lower row shows the lateral aberration at the image point of -70% of the maximum image height. Respectively. Of each lateral aberration diagram in the image blur correction state, the upper stage is the lateral aberration at the image point of 70% of the maximum image height, the middle stage is the lateral aberration at the axial image point, and the lower stage is at the image point of -70% of the maximum image height. Each corresponds to lateral aberration. In each lateral aberration diagram, the horizontal axis represents the distance from the principal ray on the pupil plane, the solid line is the d line (d-line), the short broken line is the F line (F-line), and the long broken line is the C line ( C-line), the dashed line is the characteristic of the g-line. In each lateral aberration diagram, the meridional plane is a plane including the optical axis of the first lens group G1.

For the zoom lens systems of the numerical examples, the movement amount in the direction perpendicular to the optical axis of the seventh lens element L7 in the image blur correction state at the telephoto end is as follows.
Example 1 0.151 mm
Example 2 0.174 mm
Example 3 0.150 mm
Example 4 0.183 mm

When the shooting distance is ∞ and the zoom lens system is tilted by 0.3 ° at the telephoto end, the image decentering amount is obtained when the seventh lens element L7 is translated by the above values in the direction perpendicular to the optical axis. Equal to image eccentricity.

As is clear from each lateral aberration diagram, it is understood that the symmetry of the lateral aberration at the axial image point is good. In addition, when the lateral aberration at the + 70% image point and the lateral aberration at the −70% image point are compared in the basic state, the curvature is small and the inclinations of the aberration curves are almost equal. It can be seen that the aberration is small. This means that sufficient imaging performance is obtained even in the image blur correction state. Also, when the image blur correction angle of the zoom lens system is the same, the amount of parallel movement desirable for image blur correction decreases as the focal length of the entire zoom lens system decreases. Accordingly, at any zoom position, it is possible to perform sufficient image blur correction without deteriorating the imaging characteristics for an image blur correction angle up to 0.3 °.

(Numerical example 1)
The zoom lens system of Numerical Example 1 corresponds to Embodiment 1 shown in FIG. Table 1 shows surface data of the zoom lens system of Numerical Example 1, Table 2 shows aspheric data, Table 3 shows various data in the infinite focus state, Table 4 shows single lens data, and zoom lens group data. Table 5 shows the zoom lens group magnification.

Table 1 (surface data)

Surface number r d nd vd
Object ∞
1 22.56500 0.60000 1.91082 35.2
2 8.87180 3.38880
3 * 161.15710 1.53960 1.54491 63.0
4 * 25.45760 1.09000
5 38.58320 1.11330 1.94595 18.0
6 368.16320 Variable
7 * 12.90370 2.53650 1.77010 49.7
8 * 174.20560 1.00000
9 (Aperture) ∞ 1.01210
10 52.20090 0.50000 1.80610 33.3
11 8.45000 5.00000 1.49700 81.6
12 -25.47590 0.97360
13 21.73460 1.40000 1.59282 68.6
14 * 1645.90510 variable
15 * -29.24 150 0.63030 1.51698 63.3
16 * 15.56180 (BF)
Image plane ∞

Table 2 (Aspheric data)

3rd surface K = 0.00000E + 00, A4 = -5.40561E-04, A6 = 4.99889E-06, A8 = -6.83627E-08
A10 = -2.02222E-10, A12 = 4.87115E-11, A14 = -9.69574E-13
4th surface K = -3.43984E + 01, A4 = -3.78566E-04, A6 = 1.31116E-06, A8 = -3.37486E-08
A10 = 1.68554E-09, A12 = -3.10322E-11, A14 = 0.00000E + 00
7th surface K = -1.26224E + 00, A4 = -3.84985E-05, A6 = 2.79594E-06, A8 = -5.05066E-07
A10 = 1.68520E-08, A12 = -1.68971E-10, A14 = 0.00000E + 00
8th surface K = 0.00000E + 00, A4 = -8.16943E-05, A6 = -6.87729E-07, A8 = 1.92480E-08
A10 = -3.53871E-08, A12 = 1.78570E-09, A14 = 0.00000E + 00
14th surface K = 0.00000E + 00, A4 = 5.59374E-05, A6 = 4.06840E-07, A8 = 8.98299E-08
A10 = 0.00000E + 00, A12 = 0.00000E + 00, A14 = 0.00000E + 00
15th surface K = 0.00000E + 00, A4 = 8.10385E-04, A6 = -5.52345E-06, A8 = -1.44759E-06
A10 = -6.02610E-08, A12 = 8.48779E-09, A14 = 0.00000E + 00
16th surface K = 0.00000E + 00, A4 = 9.08424E-04, A6 = -1.48426E-05, A8 = -6.19242E-07
A10 = -5.84727E-08, A12 = 5.79258E-09, A14 = 0.00000E + 00

Table 3 (Various data in focus at infinity)

Zoom ratio 2.65486
Wide angle Medium telephoto Focal length 19.2763 30.9369 51.1760
F number 7.98089 11.92627 11.97257
Angle of view 29.9768 18.9733 11.5973
Image height 10.8150 10.8150 10.8150
Total lens length 66.1204 63.7558 66.5606
BF 24.75657 30.00006 36.17954
d6 17.1286 7.4888 0.4000
d14 3.4510 5.4827 9.1969
Entrance pupil position 10.7485 8.7180 6.3473
Exit pupil position -7.4886 -8.2324 -9.3812
Front principal point position 18.5013 14.6214 0.0400
Rear principal point position 46.8440 32.8189 15.3847

Table 4 (Single lens data)

Lens Start surface Focal length 1 1 -16.3937
2 3 -55.7063
3 5 45.4883
4 7 17.9733
5 10 -12.5713
6 11 13.4242
7 13 37.1415
8 15 -19.5524

Table 5 (Zoom lens group data)

Group Start surface Focal length Lens construction length Front principal point position Rear principal point position 1 1 -18.39787 7.73170 -0.16006 0.90319
2 7 14.64158 12.42220 4.05739 5.70624
3 15 -19.55244 0.63030 0.26989 0.48667

Table 6 (zoom lens group magnification)

Group Start surface Wide angle Medium telephoto 1 1 0.00000 0.00000 0.00000
2 7 -0.46085 -0.66159 -0.97337
3 15 2.27351 2.54168 2.85773

(Numerical example 2)
The zoom lens system of Numerical Example 2 corresponds to Embodiment 2 shown in FIG. Table 7 shows surface data of the zoom lens system of Numerical Example 2, Table 8 shows aspheric data, Table 9 shows various data in the infinite focus state, Table 10 shows single lens data, and zoom lens group data. Table 11 shows the zoom lens group magnification.

Table 7 (surface data)

Surface number r d nd vd
Object ∞
1 57.68700 0.60000 1.91082 35.2
2 11.32300 2.68000
3 * 64.60800 1.40000 1.54360 56.0
4 * 19.55300 1.02000
5 17.35400 1.66000 1.94595 18.0
6 34.35900 Variable
7 * 13.05900 2.41000 1.77010 49.7
8 * -74.90500 1.00000
9 (Aperture) ∞ 3.13000
10 -48.16600 0.50000 1.80610 33.3
11 7.94200 3.17000 1.49700 81.6
12 -18.12300 0.40000
13 23.45900 1.40000 1.59282 68.6
14 ∞ Variable
15 * -36.52100 0.60000 1.51610 63.4
16 * 16.89700 variable
17 * 125.12600 3.15000 1.80500 40.9
18 * -37.30500 (BF)
Image plane ∞

Table 8 (Aspherical data)

3rd surface K = 0.00000E + 00, A4 = -1.42000E-04, A6 = 5.00000E-06, A8 = -8.99000E-08
A10 = 9.97000E-10, A12 = -5.23000E-12, A14 = 4.61000E-15
4th surface K = -2.33000E + 00, A4 = -1.26000E-04, A6 = 5.07000E-06, A8 = -1.01000E-07
A10 = 1.13000E-09, A12 = -5.73000E-12, A14 = 0.00000E + 00
7th surface K = -1.00000E + 00, A4 = -2.00000E-05, A6 = -4.20000E-07, A8 = -1.16000E-07
A10 = 4.20000E-09, A12 = -1.37000E-10, A14 = 0.00000E + 00
8th surface K = 0.00000E + 00, A4 = -3.68000E-05, A6 = -1.62000E-06, A8 = -3.10000E-08
A10 = 3.12000E-11, A12 = -6.14000E-11, A14 = 0.00000E + 00
15th surface K = 0.00000E + 00, A4 = 1.46000E-04, A6 = -9.46000E-06, A8 = 4.34000E-07
A10 = -1.05000E-08, A12 = 9.62000E-11, A14 = 0.00000E + 00
16th surface K = 0.00000E + 00, A4 = 1.92000E-04, A6 = -7.56000E-06, A8 = 2.99000E-07
A10 = -6.91000E-09, A12 = 6.04000E-11, A14 = 0.00000E + 00
17th surface K = 0.00000E + 00, A4 = -7.89000E-05, A6 = 1.20000E-06, A8 = -1.30000E-08
A10 = 9.06000E-11, A12 = -2.83000E-13, A14 = 0.00000E + 00
18th surface K = 0.00000E + 00, A4 = -9.01000E-05, A6 = 1.00000E-06, A8 = -1.02000E-08
A10 = 6.91000E-11, A12 = -2.09000E-13, A14 = 0.00000E + 00

Table 9 (Various data in infinite focus state)

Zoom ratio 2.74646
Wide angle Medium telephoto Focal length 14.6197 24.2279 40.1524
F number 3.65722 4.67234 6.12149
Angle of view 39.9158 24.6458 14.8124
Image height 10.8150 10.8150 10.8150
Total lens length 65.3281 62.3258 63.7051
BF 14.19991 14.19922 14.20096
d6 18.8807 8.1202 0.5251
d14 2.8325 7.1021 15.7923
d16 6.2950 9.7843 10.0667
Entrance pupil position 11.0104 8.7262 6.0579
Exit pupil position -26.9751 -47.6999 -65.4139
Front principal point position 20.4392 23.4711 25.9601
Rear principal point position 50.7084 38.0979 23.5526

Table 10 (Single lens data)

Lens Start surface Focal length 1 1 -15.5637
2 3 -52.1502
3 5 35.3886
4 7 14.6142
5 10 -8.4243
6 11 11.5784
7 13 39.5716
8 15 -22.2984
9 17 36.0099

Table 11 (Zoom lens group data)

Group Start surface Focal length Lens construction length Front principal point position Rear principal point position 1 1 -18.72489 7.36000 -0.15423 1.34643
2 7 16.10846 12.01000 2.54292 3.56847
3 15 -22.29843 0.60000 0.26954 0.47529
4 17 36.00993 3.15000 1.35608 2.74570

Table 12 (zoom lens group magnification)

Group Start surface Wide angle Medium telephoto 1 1 0.00000 0.00000 0.00000
2 7 -0.53599 -0.83493 -1.37703
3 15 2.45050 2.60689 2.61978
4 17 0.59444 0.59446 0.59441

(Numerical Example 3)
The zoom lens system of Numerical Example 3 corresponds to Embodiment 3 shown in FIG. Table 13 shows surface data of the zoom lens system of Numerical Example 3, Table 14 shows aspheric data, Table 15 shows various data in the infinite focus state, Table 16 shows single lens data, and zoom lens group data. Table 17 shows the zoom lens group magnification.

Table 13 (surface data)

Surface number r d nd vd
Object ∞
1 40.30130 0.60000 1.91082 35.2
2 10.71610 2.68000
3 * 204.92050 1.40000 1.54360 56.0
4 * 24.83570 1.02000
5 18.72090 1.66000 1.94595 18.0
6 37.96840 Variable
7 * 12.69190 2.41000 1.77010 49.7
8 * -76.63950 1.00000
9 (Aperture) ∞ 3.13000
10 -68.70900 0.50000 1.80610 33.3
11 7.73520 3.17000 1.49700 81.6
12 -17.80350 0.40000
13 17.91980 1.40000 1.49700 81.6
14 ∞ Variable
15 * -64.42640 0.60000 1.51610 63.4
16 * 15.47640 variable
17 * 23.48230 3.15000 1.80500 40.9
18 * 56.76900 (BF)
Image plane ∞

Table 14 (Aspherical data)

3rd surface K = 0.00000E + 00, A4 = -1.42000E-04, A6 = 5.00000E-06, A8 = -8.99000E-08
A10 = 9.97000E-10, A12 = -5.23000E-12, A14 = 4.61000E-15
4th surface K = -2.33000E + 00, A4 = -1.26000E-04, A6 = 5.07000E-06, A8 = -1.01000E-07
A10 = 1.13000E-09, A12 = -5.73000E-12, A14 = 0.00000E + 00
7th surface K = -1.00000E + 00, A4 = -2.00000E-05, A6 = -4.20000E-07, A8 = -1.16000E-07
A10 = 4.20000E-09, A12 = -1.37000E-10, A14 = 0.00000E + 00
8th surface K = 0.00000E + 00, A4 = -3.68000E-05, A6 = -1.62000E-06, A8 = -3.10000E-08
A10 = 3.12000E-11, A12 = -6.14000E-11, A14 = 0.00000E + 00
15th surface K = 0.00000E + 00, A4 = 1.46000E-04, A6 = -9.46000E-06, A8 = 4.34000E-07
A10 = -1.05000E-08, A12 = 9.62000E-11, A14 = 0.00000E + 00
16th surface K = 0.00000E + 00, A4 = 1.92000E-04, A6 = -7.56000E-06, A8 = 2.99000E-07
A10 = -6.91000E-09, A12 = 6.04000E-11, A14 = 0.00000E + 00
17th surface K = 0.00000E + 00, A4 = -7.89000E-05, A6 = 1.20000E-06, A8 = -1.30000E-08
A10 = 9.06000E-11, A12 = -2.83000E-13, A14 = 0.00000E + 00
18th surface K = 0.00000E + 00, A4 = -9.01000E-05, A6 = 1.00000E-06, A8 = -1.02000E-08
A10 = 6.91000E-11, A12 = -2.09000E-13, A14 = 0.00000E + 00

Table 15 (Various data in focus at infinity)

Zoom ratio 1.31956
Wide angle Medium telephoto Focal length 18.9726 19.6381 25.0356
F number 3.81362 3.87315 4.31403
Angle of View 32.6837 31.6324 24.8350
Image height 10.8150 10.8150 10.8150
Total lens length 57.6309 57.3511 55.4228
BF 16.47970 16.25775 15.30427
d6 9.9179 9.1953 4.4450
d14 1.1676 1.5253 4.4678
d16 6.9457 7.2527 8.0857
Entrance pupil position 9.3106 9.1228 7.6786
Exit pupil position -20.5364 -21.4582 -25.9118
Front principal point position 18.5588 18.5356 17.5070
Rear principal point position 38.6583 37.7130 30.3872

Table 16 (single lens data)

Lens Start surface Focal length 1 1 -16.1833
2 3 -52.1310
3 5 37.4690
4 7 14.3072
5 10 -8.5998
6 11 11.3162
7 13 36.0561
8 15 -24.1174
9 17 47.7345

Table 17 (Zoom lens group data)

Group Start surface Focal length Lens construction length Front principal point position Rear principal point position 1 1 -19.08671 7.36000 -0.13737 1.33919
2 7 14.91727 12.01000 3.01383 3.75944
3 15 -24.11738 0.60000 0.31829 0.52354
4 17 47.73449 3.15000 -1.18127 0.29425

Table 18 (zoom lens group magnification)

Group Start surface Wide angle Medium telephoto 1 1 0.00000 0.00000 0.00000
2 7 -0.64516 -0.66597 -0.84522
3 15 2.58976 2.57669 2.50481
4 17 0.59494 0.59959 0.61956

(Numerical example 4)
The zoom lens system of Numerical Example 4 corresponds to Embodiment 4 shown in FIG. Table 19 shows surface data of the zoom lens system in Numerical Example 4, Table 20 shows aspheric data, Table 21 shows various data in the infinite focus state, Table 22 shows single lens data, and zoom lens group data. Table 23 shows the zoom lens group magnification.

Table 19 (surface data)

Surface number r d nd vd
Object ∞
1 16.42280 0.80000 1.85400 40.4
2 * 8.69880 5.35360
3 * -16.24340 0.50000 1.58700 59.6
4 * -1000.00000 0.20000
5 21.90190 1.25200 1.94595 18.0
6 40.03200 Variable
7 * 11.89960 2.02150 1.77200 50.0
8 * -1000.00000 1.00000
9 (Aperture) ∞ 2.00000
10 25.47380 0.58990 1.90366 31.3
11 7.34840 2.70950 1.49700 81.6
12 -33.68110 1.50000
13 33.63990 1.20000 1.59282 68.6
14 -86.34380 Variable
15 * 89.01190 0.40000 1.77200 50.0
16 * 10.64130 variable
17 * 43.32750 3.19620 1.77200 50.0
18 * -62.33520 (BF) 9.654
Image plane ∞

Table 20 (Aspheric data)

2nd surface K = 0.00000E + 00, A4 = -3.04224E-05, A6 = -3.39736E-07, A8 = 0.00000E + 00
A10 = 0.00000E + 00
3rd surface K = 0.00000E + 00, A4 = 8.94998E-05, A6 = -1.77785E-06, A8 = 3.92646E-08
A10 = -3.91376E-10
4th surface K = 0.00000E + 00, A4 = 7.11423E-05, A6 = -1.79171E-06, A8 = 2.82400E-08
A10 = -2.93586E-10
7th surface K = 0.00000E + 00, A4 = -4.57043E-05, A6 = -8.52737E-08, A8 = 3.62974E-09
A10 = -1.40385E-09
8th surface K = 0.00000E + 00, A4 = 4.15779E-05, A6 = -2.33061E-07, A8 = -3.98850E-09
A10 = -1.29915E-09
15th surface K = 0.00000E + 00, A4 = 1.00000E-04, A6 = -1.10837E-05, A8 = 2.79906E-07
A10 = -2.65808E-09
16th surface K = 0.00000E + 00, A4 = 1.21515E-04, A6 = -1.15513E-05, A8 = 1.97566E-07
A10 = -9.89769E-10
17th surface K = 0.00000E + 00, A4 = 7.90705E-05, A6 = -1.03130E-06, A8 = 1.21938E-08
A10 = -8.96221E-11
18th surface K = 0.00000E + 00, A4 = 5.73840E-05, A6 = -1.13324E-06, A8 = 1.43220E-08
A10 = -1.00247E-10

Table 21 (Various data in focus at infinity)

Zoom ratio 2.76784
Wide angle Medium telephoto Focal length 14.3537 23.9034 39.7286
F number 3.62506 4.47999 5.94685
Angle of view 41.1121 24.5308 14.9900
Image height 10.8150 10.8150 10.8150
Total lens length 62.3073 56.8859 59.2609
BF 13.93740 13.71325 13.18514
d6 17.0129 6.6327 0.6000
d14 2.1442 6.6384 13.4790
d16 6.4901 7.1788 9.2741
Entrance pupil position 11.7748 9.5407 7.3316
Exit pupil position -23.0429 -29.5489 -44.9601
Front principal point position 20.5572 20.2369 19.9151
Rear principal point position 47.9536 32.9825 19.5323

Table 22 (Single lens data)

Lens Start surface Focal length 1 1 -22.7424
2 3 -28.1341
3 5 49.4633
4 7 15.2461
5 10 -11.6080
6 11 12.4096
7 13 40.9881
8 15 -15.6906
9 17 33.5522

Table 23 (Zoom lens group data)

Group Start surface Focal length Lens construction length Front principal point position Rear principal point position 1 1 -15.88153 8.10560 2.22827 3.67295
2 7 13.54864 11.02090 2.65451 3.70332
3 15 -15.69064 0.40000 0.25696 0.43072
4 17 33.55220 3.19620 0.74950 2.11789

Table 24 (zoom lens group magnification)

Group Start surface Wide angle Medium telephoto 1 1 0.00000 0.00000 0.00000
2 7 -0.51257 -0.84401 -1.35215
3 15 3.19164 3.18929 3.21812
4 17 0.55247 0.55915 0.57489

Table 25 below shows corresponding values for each condition in the zoom lens system of each numerical example.

Table 25 (corresponding values of conditions)

As described above, the embodiments have been described as examples of the technology in the present disclosure. For this purpose, the accompanying drawings and detailed description are provided.

Accordingly, among the components described in the accompanying drawings and the detailed description, not only the components essential for solving the problem, but also the components not essential for solving the problem in order to illustrate the above technique. May also be included. Therefore, it should not be immediately recognized that these non-essential components are essential as those non-essential components are described in the accompanying drawings and detailed description.

In addition, since the above-described embodiments are for illustrating the technique in the present disclosure, various modifications, replacements, additions, omissions, and the like can be made within the scope of the claims and the equivalents thereof.

The present disclosure is applicable to, for example, a digital still camera, a digital video camera, a camera of a portable information terminal such as a smartphone, a PDA (Personal Digital Assistance) camera, a surveillance camera in a surveillance system, a Web camera, an in-vehicle camera, and the like. In particular, the present disclosure is suitable for a photographing optical system that requires high image quality, such as a digital still camera system and a digital video camera system.

In addition, the zoom lens system according to the present disclosure can be applied to an interchangeable lens device equipped with an electric zoom function for driving the zoom lens system with a motor, which is included in the digital video camera system, among the interchangeable lens devices according to the present disclosure. is there.

G1 1st lens group G2 2nd lens group G3 3rd lens group G4 4th lens group L1 1st lens element L2 2nd lens element L3 3rd lens element L4 4th lens element L5 5th lens element L6 6th lens element L7 7th lens element L8 8th lens element L9 9th lens element A Aperture stop S Image surface 100 Lens interchangeable digital camera system 101 Camera body 102 Image sensor 103 Liquid crystal monitor 104 Camera mount unit 201 Interchangeable lens device 202 Zoom lens system 203 Lens tube 204 Lens mount

Claims

A zoom lens system having a plurality of lens groups each composed of at least one lens element,
From the object side to the image side,
A first lens group having negative power;
A second lens group having positive power;
A rear lens group comprising at least one lens group,
Zooming from the wide-angle end to the telephoto end during imaging by changing the interval on the optical axis of each lens group,
A zoom lens system in which at least two of the lens elements constituting the second lens group satisfy the following conditions (1) and (2):
0.660327 ≦ {(ng−nF) + 0.001802 × (nd−1)} / (nF−nC) ≦ 0.730327 (1)
(Nd-1) / (nF-nC) ≧ 50 (2)
here,
ng: refractive index with respect to g-line of lens elements constituting the second lens group,
nF: refractive index with respect to the F line of the lens elements constituting the second lens group,
nd: refractive index with respect to d-line of lens elements constituting the second lens group,
nC is the refractive index with respect to the C line of the lens elements constituting the second lens group.
The zoom lens system according to claim 1, wherein the zoom lens system satisfies the following condition (3):
1.3 ≦ M ≦ 5.0 (3)
here,
M: imaging magnification at the d-line of the rear lens group at the telephoto end.
The rear lens group
A third lens group disposed adjacent to the image side of the second lens group and having negative power;
The zoom lens system according to claim 1, further comprising a fourth lens group that is disposed adjacent to the image side of the third lens group and has a positive power.
A zoom lens system according to claim 1;
An interchangeable lens apparatus comprising: a lens mount unit that can be connected to a camera body including an imaging element that receives an optical image formed by the zoom lens system and converts the optical image into an electrical image signal.
An interchangeable lens device comprising the zoom lens system according to claim 1;
A camera system comprising: the interchangeable lens device and a camera main body including an image sensor that is detachably connected via a camera mount unit and receives an optical image formed by the zoom lens system and converts the optical image into an electrical image signal. .