WO2013065252A1

WO2013065252A1 - Zoom-lens system, imaging device, and camera

Info

Publication number: WO2013065252A1
Application number: PCT/JP2012/006781
Authority: WO
Inventors: 恭一美藤; 毅洋西岡
Original assignee: パナソニック株式会社
Priority date: 2011-11-04
Filing date: 2012-10-23
Publication date: 2013-05-10

Abstract

A zoom-lens system provided with a first lens group having positive power, a second lens group having negative power, a third lens group having positive power, and a fourth lens group, in that order from the object side to the image side. The first lens group has a lens element that has a reflective surface for changing the direction of light rays from the object. When zooming from the wide-angle end to the telephoto end when imaging, the second and fourth lens groups move along the optical axis but the first lens group does not. This zoom-lens system satisfies the condition 2.8 < L/(D₁+D₂) < 4.0 (L represents the total lens length, D₁ represents the distance that the second lens group moves when zooming, and D₂ represents the distance that the fourth lens group moves when zooming).

Description

Zoom lens system, imaging device and camera

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

Demand for downsizing and high performance of a camera having an image sensor that performs photoelectric conversion (hereinafter simply referred to as a digital camera) such as a digital still camera or a digital video camera is extremely strong. In particular, in recent years, there has been a demand for a thin digital camera with the highest priority on storage and portability. As one of means for realizing such a thin digital camera, various zoom lens systems for bending light rays from an object have been proposed.

For example, Patent Documents 1 to 3 have five groups including a first lens group having a positive power and including a lens element having a reflecting surface that bends a light beam from an object, and a second lens group having a negative power. A zoom type lens system is disclosed.

JP 2010-107566 A JP 2009-103853 A JP 2008-0665347 A

The present disclosure provides a compact zoom lens system having not only excellent optical performance but also a relatively high zoom ratio and a short overall lens length. The present disclosure also provides an imaging apparatus including the zoom lens system and a thin and compact camera including the imaging apparatus.

The zoom lens system in the present disclosure is:
From the object side to the image side,
A first lens group having positive power;
A second lens group having negative power;
A third lens group having positive power;
A fourth lens group,
The first lens group includes a lens element having a reflecting surface for bending light rays from an object,
During zooming from the wide-angle end to the telephoto end during imaging, the first lens group does not move along the optical axis, and the second lens group and the fourth lens group move along the optical axis,
The following conditions (1):
2.8 <L / (D ₁ + D ₂ ) <4.0 (1)
(here,
L: total lens length (distance from the most object side lens surface of the first lens group to the image plane),
D ₁ : the amount of movement of the second lens group during zooming from the wide-angle end to the telephoto end during imaging,
D ₂ is the amount of movement of the fourth lens group during zooming from the wide-angle end to the telephoto end during imaging)
It is characterized by satisfying.

An imaging apparatus according to the present disclosure
An imaging apparatus capable of outputting an optical image of an object as an electrical image signal,
A zoom lens system that forms an optical image of the object;
An image sensor that converts an optical image formed by the zoom lens system into an electrical image signal;
The zoom lens system is
From the object side to the image side,
A first lens group having positive power;
A second lens group having negative power;
A third lens group having positive power;
A fourth lens group,
The first lens group includes a lens element having a reflecting surface for bending light rays from an object,
During zooming from the wide-angle end to the telephoto end during imaging, the first lens group does not move along the optical axis, and the second lens group and the fourth lens group move along the optical axis,
The following conditions (1):
2.8 <L / (D ₁ + D ₂ ) <4.0 (1)
(here,
L: total lens length (distance from the most object side lens surface of the first lens group to the image plane),
D ₁ : the amount of movement of the second lens group during zooming from the wide-angle end to the telephoto end during imaging,
D ₂ is the amount of movement of the fourth lens group during zooming from the wide-angle end to the telephoto end during imaging)
This zoom lens system satisfies the above.

The camera in the present disclosure is
A camera that converts an optical image of an object into an electrical image signal, and displays and stores the converted image signal;
An image pickup apparatus including a zoom lens system that forms an optical image of an object, and an image sensor that converts an optical image formed by the zoom lens system into an electrical image signal;
The zoom lens system is
From the object side to the image side,
A first lens group having positive power;
A second lens group having negative power;
A third lens group having positive power;
A fourth lens group,
The first lens group includes a lens element having a reflecting surface for bending light rays from an object,
During zooming from the wide-angle end to the telephoto end during imaging, the first lens group does not move along the optical axis, and the second lens group and the fourth lens group move along the optical axis,
The following conditions (1):
2.8 <L / (D ₁ + D ₂ ) <4.0 (1)
(here,
L: total lens length (distance from the most object side lens surface of the first lens group to the image plane),
D ₁ : the amount of movement of the second lens group during zooming from the wide-angle end to the telephoto end during imaging,
D ₂ is the amount of movement of the fourth lens group during zooming from the wide-angle end to the telephoto end during imaging)
This zoom lens system satisfies the above.

The zoom lens system according to the present disclosure not only has excellent optical performance, but also has a relatively high zoom ratio and a short overall lens length.

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 a digital still camera 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 directions in which a later-described fourth lens group G4 moves during focusing from an infinite focus state to a close object focus state.

The zoom lens system according to each embodiment includes, in order from the object side to the image side, a first lens group G1 having a positive power, a second lens group G2 having a negative power, and a first lens group having a positive power. 3 lens group G3, 4th lens group G4 which has positive power, and 5th lens group G5 which has positive power are provided. The second lens element L2 (prism) in the first lens group G1 corresponds to a lens element that has a reflecting surface that bends light rays from the object, for example, bends an axial principal ray from the object by approximately 90 °. The position is omitted. In the zoom lens system according to each embodiment, the lens element having a reflective surface is a prism, but the lens element having the reflective surface may be, for example, a mirror element. In addition, as will be described later, the prisms arranged in the zoom lens system according to each embodiment are both flat on the entrance surface and the exit surface, but at least one of the entrance surface and the exit surface depends on the lens configuration. It may be convex or concave.

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 distance between the second lens group G2 and the third lens group G3, and the third lens group G3 and the fourth lens group G4. The second lens group G2 and the fourth lens group G4 are respectively in the direction along the optical axis so that the distance between the lens group G4 and the distance between the fourth lens group G4 and the fifth lens group G5 are changed. Moving. 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 drawing, the straight line described on the rightmost side represents the position of the image plane S, and is located on the object side of the image plane S (between the image plane S and the most image side lens surface of the fifth lens group G5). Are provided with a parallel plate P equivalent to an optical low-pass filter, a face plate of an image sensor, or the like.

(Embodiment 1)
As shown in FIG. 1, the first lens group G1 has a negative meniscus first lens element L1 with a convex surface facing the object side in order from the object side to the image side, and both the entrance surface and the exit surface are flat. It consists of a second lens element L2 (prism) having a reflecting surface and a biconvex third lens element L3. Among these, the third lens element L3 has two aspheric surfaces.

The second lens group G2 includes, in order from the object side to the image side, a biconcave fourth lens element L4 and a positive meniscus fifth lens element L5 with a convex surface facing the object side. Among these, the fourth lens element L4 has two aspheric surfaces.

The third lens group G3 includes, in order from the object side to the image side, a biconvex sixth lens element L6 and a negative meniscus seventh lens element L7 with a convex surface facing the image side. The sixth lens element L6 and the seventh lens element L7 are cemented, and in the surface data in the corresponding numerical value example described later, an adhesive layer between the sixth lens element L6 and the seventh lens element L7 is used. Surface number 12 is given. The sixth lens element L6 has an aspheric object side surface. An aperture stop A is provided on the most image side of the third lens group G3.

The fourth lens group G4 includes, in order from the object side to the image side, a biconvex eighth lens element L8, a biconvex ninth lens element L9, and a biconcave tenth lens element L10. . Among these, the ninth lens element L9 and the tenth lens element L10 are cemented, and in the surface data in the corresponding numerical value example described later, the adhesion between the ninth lens element L9 and the tenth lens element L10. Surface number 19 is given to the agent layer. The ninth lens element L9 has an aspheric object side surface.

The fifth lens group G5 comprises solely a biconvex eleventh lens element L11. The eleventh lens element L11 has two aspheric surfaces.

On the object side of the image plane S (between the image plane S and the eleventh lens element L11), a parallel plate P is provided.

In the zoom lens system according to Embodiment 1, during zooming from the wide-angle end to the telephoto end during imaging, the second lens group G2 monotonously moves to the image side, and the fourth lens group G4 is substantially monotonous. The first lens group G1, the third lens group G3, and the fifth lens group G5 are 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 increases, the distance between the second lens group G2 and the third lens group G3 decreases, and the third lens group G3 and the fourth lens. The second lens group G2 and the fourth lens group G4 move along the optical axis so that the distance between the group G4 decreases and the distance between the fourth lens group G4 and the fifth lens group G5 increases.

Furthermore, in the zoom lens system according to Embodiment 1, the fourth lens group G4 moves toward the object side along the optical axis during focusing from the infinite focus state to the close object focus state.

(Embodiment 2)
As shown in FIG. 4, the first lens group G1 has a negative meniscus first lens element L1 with a convex surface facing the object side in order from the object side to the image side, and both the incident surface and the exit surface are flat. It consists of a second lens element L2 (prism) having a reflecting surface and a biconvex third lens element L3. Among these, the third lens element L3 has two aspheric surfaces.

The third lens group G3 includes, in order from the object side to the image side, a biconvex sixth lens element L6 and a negative meniscus seventh lens element L7 with a convex surface facing the image side. Among these, the seventh lens element L7 has an aspheric image side surface. An aperture stop A is provided on the most image side of the third lens group G3.

The fourth lens group G4 includes, in order from the object side to the image side, a biconvex eighth lens element L8, a biconvex ninth lens element L9, and a biconcave tenth lens element L10. . Among these, the ninth lens element L9 and the tenth lens element L10 are cemented, and in the surface data in the corresponding numerical value example described later, the adhesion between the ninth lens element L9 and the tenth lens element L10. Surface number 19 is given to the agent layer. The eighth lens element L8 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 second lens group G2 monotonously moves to the image side, and the fourth lens group G4 is substantially monotonous. The first lens group G1, the third lens group G3, and the fifth lens group G5 are 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 increases, the distance between the second lens group G2 and the third lens group G3 decreases, and the third lens group G3 and the fourth lens. The second lens group G2 and the fourth lens group G4 move along the optical axis so that the distance between the group G4 decreases and the distance between the fourth lens group G4 and the fifth lens group G5 increases.

Furthermore, in the zoom lens system according to Embodiment 2, the fourth lens group G4 moves toward the object side along the optical axis during focusing from the infinite focus state to the close object focus state.

(Embodiment 3)
As shown in FIG. 7, the first lens group G1 has a negative meniscus first lens element L1 with a convex surface facing the object side in order from the object side to the image side, and both the incident surface and the exit surface are flat. It consists of a second lens element L2 (prism) having a reflecting surface and a biconvex third lens element L3. Among these, the third lens element L3 has two aspheric surfaces.

The third lens group G3 is composed of a biconvex sixth lens element L6 and a biconcave seventh lens element L7 in order from the object side to the image side. Among these, the seventh lens element L7 has an aspheric image side surface. An aperture stop A is provided on the most object side of the third lens group G3.

In the zoom lens system according to Embodiment 3, during zooming from the wide-angle end to the telephoto end during imaging, the second lens group G2 monotonously moves to the image side, and the fourth lens group G4 is substantially monotonous. The first lens group G1, the third lens group G3, and the fifth lens group G5 are 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 increases, the distance between the second lens group G2 and the third lens group G3 decreases, and the third lens group G3 and the fourth lens. The second lens group G2 and the fourth lens group G4 move along the optical axis so that the distance between the group G4 decreases and the distance between the fourth lens group G4 and the fifth lens group G5 increases.

Furthermore, in the zoom lens system according to Embodiment 3, the fourth lens group G4 moves toward the object side along the optical axis during focusing from the infinite focus state to the close object focus state.

(Embodiment 4)
As shown in FIG. 10, the first lens group G1 has a negative meniscus first lens element L1 with a convex surface facing the object side in order from the object side to the image side, and both the entrance surface and the exit surface are flat. It consists of a second lens element L2 (prism) having a reflecting surface and a biconvex third lens element L3. Among these, the third lens element L3 has two aspheric surfaces.

The third lens group G3 is composed of a biconvex sixth lens element L6 and a biconcave seventh lens element L7 in order from the object side to the image side. The sixth lens element L6 and the seventh lens element L7 are cemented, and in the surface data in the corresponding numerical value example described later, an adhesive layer between the sixth lens element L6 and the seventh lens element L7 is used. Surface number 12 is given. The sixth lens element L6 has an aspheric object side surface. An aperture stop A is provided on the most image side of the third lens group G3.

In the zoom lens system according to Embodiment 4, during zooming from the wide-angle end to the telephoto end during imaging, the second lens group G2 monotonously moves to the image side, and the fourth lens group G4 is substantially monotonous. The first lens group G1, the third lens group G3, and the fifth lens group G5 are 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 increases, the distance between the second lens group G2 and the third lens group G3 decreases, and the third lens group G3 and the fourth lens. The second lens group G2 and the fourth lens group G4 move along the optical axis so that the distance between the group G4 decreases and the distance between the fourth lens group G4 and the fifth lens group G5 increases.

Furthermore, in the zoom lens system according to Embodiment 4, the fourth lens group G4 moves toward the object side along the optical axis when focusing from the infinite focus state to the close object focus state.

In the zoom lens systems according to Embodiments 1 to 4, the first lens group G1 has a reflecting surface that can bend the light beam from the object, for example, can bend the axial principal ray from the object by approximately 90 °. Since the second lens element L2 (prism) is included, the zoom lens system can be made thin in the optical axis direction of the axial ray from the object in the imaging state.

In the zoom lens systems according to Embodiments 1 to 4, the first lens group G1 does not move along the optical axis during zooming from the wide-angle end to the telephoto end during imaging, so that the zoom lens system is housed. As the lens barrel, a lens barrel that does not change its shape due to zooming can be used, and a camera with a high degree of freedom in shape and excellent impact resistance can be manufactured.

In the zoom lens systems according to Embodiments 1 to 4, since the fourth lens group G4 and the fifth lens group G5 disposed immediately on the image side of the fourth lens group G4 have positive power, Various aberrations can be corrected satisfactorily over the entire area, and further downsizing can be achieved while maintaining high performance.

In the zoom lens systems according to Embodiments 1 to 4, since the second lens group has two lens elements and an air space between the two lens elements, various aberrations, particularly distortion, are excellent. Can be corrected.

The zoom lens systems according to Embodiments 1 to 4 have a five-group configuration including a first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. However, the zoom lens system according to the present disclosure includes a first lens group having a positive power, a second lens group having a negative power, a third lens group having a positive power, and a fourth lens group. As long as the number of lens groups is not particularly limited, a 4-group or 5-group configuration may be used, or any other configuration.

Further, as described above, it is beneficial that the fourth lens group G4 and the fifth lens group G5 disposed immediately on the image side of the fourth lens group G4 have positive power. There is no particular limitation on the power of the lens group G4 and the power of the lens group disposed on the image side of the fourth lens group G4.

In the zoom lens systems according to Embodiments 1 to 4, when zooming from the wide-angle end to the telephoto end during imaging, the second lens group G2 and the fourth lens group G4 are arranged along the optical axis among all the lens groups. Each of the lens groups, or a sub-lens group of a part of each lens group, for example, the third lens group G3 in a direction perpendicular to the optical axis. Therefore, it is possible to correct image point movement due to vibration of the entire system, that is, to optically correct image blur due to camera shake or vibration.

When correcting the image point movement due to the vibration of the entire system, for example, the third lens group G3 moves in a direction perpendicular to the optical axis, thereby suppressing the enlargement of the entire zoom lens system and making it compact. However, it is possible to correct image blur while maintaining excellent imaging characteristics with small decentration coma and decentering astigmatism.

In addition, when one lens group is composed of a plurality of lens elements, a part of the sub-lens groups of each lens group is any one of the plurality of lens elements or adjacent to each other. A plurality of lens elements.

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, in order from the object side to the image side, a first lens group having a positive power, a second lens group having a negative power, and a positive power And a fourth lens group, and the first lens group has a lens element having a reflecting surface for bending light rays from the object, from the wide-angle end to the telephoto end during imaging. During zooming, the first lens group does not move along the optical axis, and the second lens group and the fourth lens group move along the optical axis. The zoom lens system (referred to as basic configuration of the form) satisfies the following condition (1).
2.8 <L / (D ₁ + D ₂ ) <4.0 (1)
here,
L: total lens length (distance from the most object side lens surface of the first lens group to the image plane),
D ₁ : the amount of movement of the second lens group during zooming from the wide-angle end to the telephoto end during imaging,
D ₂ is the amount of movement of the fourth lens group during zooming from the wide-angle end to the telephoto end during imaging.

The condition (1) is a condition for defining a ratio between the total lens length and the total movement amount of the second lens group and the fourth lens group during zooming. If the lower limit of the condition (1) is not reached, the total lens length becomes too short with respect to the total amount of movement of the second lens group and the fourth lens group, and the power of each lens group becomes small. As a result, the aberration fluctuations become large and correction of various aberrations becomes difficult. On the contrary, if the upper limit of the condition (1) is exceeded, the total lens length becomes too long with respect to the sum of the movement amount of the second lens group and the movement amount of the fourth lens group. It becomes difficult to provide.

The above effect can be further achieved by satisfying at least one of the following conditions (1) ′ and (1) ″.
3.0 <L / (D ₁ + D ₂ ) (1) ′
L / (D ₁ + D ₂ ) <3.8 (1) ″

For example, a zoom lens system having a basic configuration like the zoom lens systems according to Embodiments 1 to 4 is beneficial to satisfy the following condition (2).
1.5 <f _W × D _A / {f _T × tan (ω _T )} ² <2.5 (2)
here,
f _W : focal length of the entire system at the wide-angle end,
f _T : focal length of the entire system at the telephoto end,
D _A : the thickness on the optical axis of the lens element having a reflecting surface for bending the light beam from the object,
ω _T : half value of the maximum field angle at the telephoto end.

The condition (2) is a condition for defining the product of the focal length of the entire system at the wide-angle end and the thickness on the optical axis of the lens element having a reflecting surface for bending the light beam from the object. If the lower limit of the condition (2) is not reached, the thickness of the lens element having the reflecting surface on the optical axis becomes too small, and the effective light beam diameter of the lens element having the reflecting surface becomes too small. It becomes difficult to ensure. On the contrary, if the upper limit of the condition (2) is exceeded, the focal length of the entire system at the wide angle end becomes large, and it becomes difficult to ensure a sufficiently wide angle of view. Or since the thickness on the optical axis of the lens element which has a reflective surface becomes large, it becomes difficult to provide a compact lens barrel, an imaging device, and a camera.

In addition, when the following condition (2) ′ is further satisfied, the above effect can be further achieved.
2.0 <f _W × D _A / {f _T × tan (ω _T )} ² (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 diffraction and refraction, and a refractive index that deflects incident light by 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.

Further, in each embodiment, an optical low-pass filter, a face plate of an image sensor, or the like is equivalent to the object side of the image plane S (between the image plane S and the most image side lens surface of the fifth lens group G5). Although the configuration in which the parallel plate P is arranged is shown, as this low-pass filter, a birefringent low-pass filter made of quartz or the like whose predetermined crystal axis direction is adjusted, or a required optical cutoff frequency. A phase-type low-pass filter or the like that achieves the characteristics by the diffraction effect can be applied.

(Embodiment 5)
FIG. 13 is a schematic configuration diagram of a digital still camera according to the fifth embodiment. In FIG. 13, the digital still camera includes an image pickup apparatus including a zoom lens system 1 and an image pickup device 2 that is a CCD, a liquid crystal monitor 3, and a housing 4. As the zoom lens system 1, the zoom lens system according to Embodiment 1 is used. In FIG. 13, the zoom lens system 1 includes a first lens group G1, a second lens group G2, a third lens group G3 including an aperture stop A, a fourth lens group G4, and a fifth lens group G5. It is configured. In the housing 4, the zoom lens system 1 is disposed on the front side, and the imaging element 2 is disposed on the rear side of the zoom lens system 1. A liquid crystal monitor 3 is disposed on the rear side of the housing 4, and an optical image of the subject by the zoom lens system 1 is formed on the image plane S.

Thus, by using the zoom lens system according to Embodiment 1 for a digital still camera, it is possible to provide a small digital still camera that has a high ability to correct resolution and curvature of field and has a short overall lens length when not in use. it can. In the digital still camera shown in FIG. 13, any of the zoom lens systems according to Embodiments 2 to 4 may be used instead of the zoom lens system according to Embodiment 1. Further, the optical system of the digital still camera shown in FIG. 13 can also be used for a digital video camera for moving images. In this case, not only a still image but also a moving image with high resolution can be taken.

In the digital still camera according to the fifth embodiment, the zoom lens system according to the first to fourth embodiments is shown as the zoom lens system 1, but these zoom lens systems do not use the entire zooming area. May be. That is, a range in which the optical performance is ensured may be cut out according to a desired zooming area, and used as a zoom lens system having a lower magnification than the zoom lens system described in the first to fourth embodiments.

In addition, an image pickup apparatus including the zoom lens system according to Embodiments 1 to 4 described above and an image pickup device such as a CCD or a CMOS is used as a camera for a portable information terminal such as a smartphone, a monitoring camera for a monitoring system, a Web The present invention can also be applied to cameras, in-vehicle cameras, and the like.

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 vd 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). 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).

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 a basic state in which no image blur correction is performed at the telephoto end, and the lower three aberration diagrams move the entire third lens group G3 by a predetermined amount in a direction perpendicular to the optical axis. This corresponds to the image blur correction state at the telephoto end. 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) characteristics. In each lateral aberration diagram, the meridional plane is a plane including the optical axis of the first lens group G1 and the optical axis of the third lens group G3.

For the zoom lens systems of the numerical examples, the amount of movement in the direction perpendicular to the optical axis of the third lens group G3 in the image blur correction state at the telephoto end is as follows.
Numerical example 1 0.057 mm
Numerical example 2 0.063 mm
Numerical example 3 0.067 mm
Numerical example 4 0.090 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 when the entire third lens group G3 is translated by the above values in the direction perpendicular to the optical axis. Is equal to the amount of 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. When the image blur correction angle of the zoom lens system is the same, the amount of parallel movement required 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, and Table 3 shows various data.

Table 1 (surface data)

Surface number r d nd vd
Object ∞
1 55.32020 0.30000 2.00272 19.3
2 10.05990 1.91420
3 ∞ 7.74970 1.84666 23.8
4 ∞ 0.15000
5 * 10.81330 2.45960 1.76681 49.7
6 * -18.10640 variable
7 * -10.66560 0.50000 1.76681 49.7
8 * 3.71540 0.69640
9 6.01790 0.91440 1.94595 18.0
10 11.60840 Variable
11 * 13.82380 1.13390 1.80470 41.0
12 -6.06820 0.01000 1.56732 42.8
13 -6.06820 0.30000 1.72825 28.3
14 -54.37500 1.40000
15 (Aperture) ∞ Variable
16 5.55560 2.57520 1.49700 81.6
17 -17.53130 0.15000
18 * 10.31070 2.48730 1.58332 59.1
19 -4.58010 0.01000 1.56732 42.8
20 -4.58010 0.54650 1.90366 31.3
21 5.80420 Variable
22 * 11.38970 2.11630 1.52996 55.8
23 * -22.47300 1.56810
24 ∞ 0.60000 1.51680 64.2
25 ∞ 0.37000
Image plane ∞

Table 2 (Aspheric data)

5th surface K = 0.00000E + 00, A4 = -1.39779E-04, A6 = -5.69411E-07, A8 = -1.06898E-08
A10 = -4.12215E-10
6th surface K = 0.00000E + 00, A4 = 6.81171E-05, A6 = -6.39098E-07, A8 = 2.83872E-09
A10 = -3.85521E-10
7th surface K = 0.00000E + 00, A4 = -2.99952E-05, A6 = 6.80376E-05, A8 = -5.33952E-06
A10 = 1.83170E-07
8th surface K = -2.40921E-01, A4 = -2.01561E-03, A6 = 1.98430E-05, A8 = -4.11420E-06
A10 = 2.47916E-08
11th surface K = 0.00000E + 00, A4 = -1.36112E-04, A6 = -2.03260E-05, A8 = 4.87452E-06
A10 = -4.67253E-07
18th surface K = 0.00000E + 00, A4 = -5.80086E-04, A6 = 4.16760E-07, A8 = -2.13784E-06
A10 = 1.86164E-07
22nd surface K = 0.00000E + 00, A4 = 9.63663E-04, A6 = -1.11055E-05, A8 = -6.03768E-07
A10 = 1.87812E-08
23rd face K = 0.00000E + 00, A4 = 1.57684E-03, A6 = -2.51251E-05, A8 = -2.66167E-06
A10 = 7.78641E-08

Table 3 (various data)

Zoom ratio 3.83406
Wide angle Medium telephoto Focal length 4.5567 8.9170 17.4707
F number 4.04304 5.08877 6.11134
Angle of View 41.8496 23.6451 12.3700
Image height 3.4770 3.8920 3.8920
Total lens length 45.4477 45.4476 45.4477
d6 0.6000 3.5833 6.3433
d10 6.3933 3.4099 0.6500
d15 9.1028 5.2370 2.2000
d21 1.4000 5.2658 8.3028
Entrance pupil position 7.4758 10.1072 13.6383
Exit pupil position -23.1762 -37.0339 -66.1507
Front principal point position 11.1387 16.8758 26.4913
Rear principal point position 40.9447 36.5061 27.9252

Single lens data Lens Start surface Focal length 1 1 -12.3033
2 3 ∞
3 5 9.1673
4 7 -3.5401
5 9 12.2370
6 11 5.3772
7 13 -9.4039
8 16 8.8148
9 18 5.7932
10 20 -2.7639
11 22 14.5785

Zoom lens group data Group Start surface Focal length Lens construction length Front principal point position Rear principal point position 1 1 11.38835 12.57350 8.59125 17.93305
2 7 -5.15889 2.11080 0.08035 0.76996
3 11 12.03419 2.84390 0.22330 0.84940
4 16 27.99456 5.76900 -17.21681 -7.06120
5 22 14.57852 4.28440 0.47555 1.38243

Zoom lens group magnification group Start surface Wide angle Medium telephoto 1 1 0.00000 0.00000 0.00000
2 7 -0.47292 -0.65093 -0.99874
3 11 -3.41699 -8.26051 -24.49682
4 16 0.32078 0.18735 0.08048
5 22 0.77188 0.77724 0.77912

(Numerical example 2)
The zoom lens system of Numerical Example 2 corresponds to Embodiment 2 shown in FIG. Table 4 shows surface data of the zoom lens system of Numerical Example 2, Table 5 shows aspheric data, and Table 6 shows various data.

Table 4 (surface data)

Surface number r d nd vd
Object ∞
1 68.65880 0.30000 2.00272 19.3
2 9.88400 1.99840
3 ∞ 7.90000 1.84666 23.8
4 ∞ 0.15000
5 * 12.48580 2.80000 1.76681 49.7
6 * -16.29730 Variable
7 * -12.30580 0.50000 1.76681 49.7
8 * 3.97600 0.66450
9 5.96940 1.01000 1.94595 18.0
10 11.51950 Variable
11 8.43790 1.21000 1.53172 48.8
12 -8.43790 0.15000
13 -9.63780 0.60000 1.63550 23.9
14 * -46.55380 1.40000
15 (Aperture) ∞ Variable
16 * 5.63940 2.22000 1.52996 55.8
17 * -15.45380 0.15000
18 5.61390 2.24000 1.49700 81.6
19 -6.31550 0.01000 1.56732 42.8
20 -6.31550 0.70000 2.00100 29.1
21 4.35230 Variable
22 * 12.48100 2.00000 1.52996 55.8
23 * -34.69420 1.00000
24 ∞ 0.60000 1.51680 64.2
25 ∞ 0.37000
Image plane ∞

Table 5 (Aspheric data)

5th surface K = 0.00000E + 00, A4 = -1.40047E-04, A6 = 6.05607E-07, A8 = -3.01600E-08
A10 = 3.95126E-10
6th surface K = 0.00000E + 00, A4 = 3.34858E-05, A6 = 7.64444E-07, A8 = -3.22057E-08
A10 = 4.96677E-10
7th surface K = 0.00000E + 00, A4 = -4.56081E-04, A6 = 6.69082E-05, A8 = -4.34674E-06
A10 = 1.26585E-07
8th surface K = -5.56317E-01, A4 = -1.15487E-03, A6 = 6.31133E-05, A8 = -4.41083E-06
A10 = 1.49813E-07
14th surface K = 0.00000E + 00, A4 = 3.09872E-04, A6 = 8.49527E-05, A8 = -2.32049E-05
A10 = 2.71920E-06
16th surface K = 0.00000E + 00, A4 = 1.86586E-04, A6 = 3.98838E-06, A8 = 2.75127E-07
A10 = 3.78214E-09
17th surface K = 0.00000E + 00, A4 = 7.52446E-04, A6 = -1.85390E-06, A8 = -9.89481E-08
A10 = -1.42653E-08
22nd surface K = 0.00000E + 00, A4 = -2.55948E-04, A6 = 1.82614E-04, A8 = -1.07529E-05
A10 = 2.26616E-07
23rd surface K = 0.00000E + 00, A4 = -1.66318E-03, A6 = 3.93105E-04, A8 = -2.34599E-05
A10 = 4.54497E-07

Table 6 (various data)

Zoom ratio 3.82543
Wide angle Medium telephoto Focal length 4.5541 8.9082 17.4212
F number 4.04192 5.09009 6.10335
Angle of View 41.4983 23.5044 12.4026
Image height 3.4410 3.9020 3.9020
Total lens length 45.4524 45.4523 45.4525
d6 0.6000 3.9847 7.1170
d10 7.1670 3.7822 0.6500
d15 7.5501 4.5293 2.0582
d21 2.1624 5.1832 7.6544
Entrance pupil position 7.5314 10.2427 13.8970
Exit pupil position -15.1272 -21.0354 -28.8206
Front principal point position 10.7187 15.3811 20.7842
Rear principal point position 40.9457 36.5588 28.0221

Single lens data Lens Start surface Focal length 1 1 -11.5443
2 3 ∞
3 5 9.6259
4 7 -3.8674
5 9 12.0333
6 11 8.1371
7 13 -19.2466
8 16 8.0912
9 18 6.3776
10 20 -2.4922
11 22 17.5782

Zoom lens group data Group Start surface Focal length Lens configuration length Front principal point position Rear principal point position 1 1 12.29616 13.14840 9.26915 19.79405
2 7 -5.85662 2.17450 0.10408 0.85188
3 11 13.53803 3.36000 0.08243 0.73130
4 16 24.16146 5.32000 -18.42739 -6.93327
5 22 17.57820 3.60000 0.35100 1.22873

Zoom lens group magnification group Start surface Wide angle Medium telephoto 1 1 0.00000 0.00000 0.00000
2 7 -0.47303 -0.65099 -0.99872
3 11 -3.69792 -10.26802 -60.77135
4 16 0.25 165 0.12853 0.02764
5 22 0.84136 0.84322 0.84457

(Numerical Example 3)
The zoom lens system of Numerical Example 3 corresponds to Embodiment 3 shown in FIG. Table 7 shows surface data of the zoom lens system of Numerical Example 3, Table 8 shows aspheric data, and Table 9 shows various data.

Table 7 (surface data)

Surface number r d nd vd
Object ∞
1 46.93000 0.30000 2.00272 19.3
2 8.93120 1.99410
3 ∞ 7.42000 1.84666 23.8
4 ∞ 0.15000
5 * 12.39480 2.60000 1.76681 49.7
6 * -16.60730 variable
7 * -13.34410 0.50000 1.76681 49.7
8 * 4.20360 0.63280
9 6.14600 1.00000 1.94595 18.0
10 12.01580 Variable
11 (Aperture) ∞ 0.85000
12 9.35 300 1.12000 1.54814 45.8
13 -9.35300 0.15000
14 -12.35 180 0.60000 1.63550 23.9
15 * 154.69170 variable
16 * 5.28630 2.42000 1.52996 55.8
17 * -22.48140 0.15000
18 5.56290 2.67000 1.49700 81.6
19 -4.67160 0.01000 1.56732 42.8
20 -4.67160 0.70000 2.00100 29.1
21 4.14970 Variable
22 * 17.29270 2.44000 1.52996 55.8
23 * -9.49880 0.78850
24 ∞ 0.50000 1.51680 64.2
25 ∞ 0.37000
Image plane ∞

Table 8 (Aspherical data)

5th surface K = 0.00000E + 00, A4 = -1.90274E-04, A6 = -7.99606E-07, A8 = 9.39275E-08
A10 = -2.73985E-09, A12 = 0.00000E + 00, A14 = 0.00000E + 00, A16 = 0.00000E + 00
6th surface K = 0.00000E + 00, A4 = -5.45762E-05, A6 = 1.03639E-06, A8 = 3.04122E-08
A10 = -1.70060E-09, A12 = 0.00000E + 00, A14 = 0.00000E + 00, A16 = 0.00000E + 00
7th surface K = 0.00000E + 00, A4 = -7.72244E-04, A6 = 7.82721E-05, A8 = -3.32334E-06
A10 = 7.79930E-08, A12 = 0.00000E + 00, A14 = 0.00000E + 00, A16 = 0.00000E + 00
8th surface K = -4.84027E-01, A4 = -1.32994E-03, A6 = 6.48856E-05, A8 = -1.22011E-06
A10 = 7.21849E-08, A12 = 0.00000E + 00, A14 = 0.00000E + 00, A16 = 0.00000E + 00
15th surface K = 0.00000E + 00, A4 = 3.74799E-04, A6 = 1.39103E-05, A8 = -2.98561E-06
A10 = 3.81732E-07, A12 = 0.00000E + 00, A14 = 0.00000E + 00, A16 = 0.00000E + 00
16th surface K = 0.00000E + 00, A4 = 3.94704E-04, A6 = -1.89999E-05, A8 = 2.84952E-06
A10 = -8.17298E-08, A12 = 0.00000E + 00, A14 = 0.00000E + 00, A16 = 0.00000E + 00
17th surface K = 0.00000E + 00, A4 = 8.82886E-04, A6 = -4.05639E-05, A8 = 3.70916E-06
A10 = -1.77627E-07, A12 = 0.00000E + 00, A14 = 0.00000E + 00, A16 = 0.00000E + 00
22nd surface K = 0.00000E + 00, A4 = 6.63960E-05, A6 = -3.20982E-05, A8 = 1.28816E-05
A10 = -1.03818E-06, A12 = 2.73096E-08, A14 = 2.22328E-10, A16 = -1.98662E-11
23rd surface K = 0.00000E + 00, A4 = -1.07874E-04, A6 = -1.33878E-04, A8 = 2.54473E-05
A10 = -1.19583E-06, A12 = -2.04052E-09, A14 = 1.25835E-09, A16 = -2.36606E-11

Table 9 (various data)

Zoom ratio 3.81912
Wide angle Medium telephoto Focal length 4.5736 8.9432 17.4670
F number 4.04409 5.06880 6.07256
Angle of View 41.1750 23.5289 12.5047
Image height 3.4210 3.9180 3.9180
Total lens length 45.4459 45.4459 45.4460
d6 0.4179 3.9219 7.2285
d10 8.0106 4.5065 1.2000
d15 7.3038 4.4812 2.0667
d21 2.3482 5.1709 7.5854
Entrance pupil position 7.0260 9.2911 11.7303
Exit pupil position -26.5688 -59.0389 -347.0251
Front principal point position 10.8137 16.8797 28.3181
Rear principal point position 40.9190 36.5072 27.9654

Single lens data Lens Start surface Focal length 1 1 -11.0441
2 3 ∞
3 5 9.6307
4 7 -4.1178
5 9 12.2829
6 12 8.7164
7 14 -17.9741
8 16 8.3273
9 18 5.5936
10 20 -2.1116
11 22 11.9457

Zoom lens group data Group Start surface Focal length Lens construction length Front principal point position Rear principal point position 1 1 12.97951 12.46410 9.32493 19.55689
2 7 -6.35228 2.13280 0.10767 0.84838
3 11 15.97947 2.72000 0.73357 1.37859
4 16 25.53240 5.95000 -25.87620 -8.67772
5 22 11.94573 3.72850 1.06291 2.02651

Zoom lens group magnification group Start surface Wide angle Medium telephoto 1 1 0.00000 0.00000 0.00000
2 7 -0.48144 -0.65552 -0.99505
3 11 -4.61886 -15.05595 180.87758
4 16 0.19262 0.08450 -0.00903
5 22 0.82264 0.82618 0.82768

(Numerical example 4)
The zoom lens system of Numerical Example 4 corresponds to Embodiment 4 shown in FIG. Table 10 shows surface data of the zoom lens system of Numerical Example 4, Table 11 shows aspheric data, and Table 12 shows various data.

Table 10 (surface data)

Surface number r d nd vd
Object ∞
1 103.02920 0.30000 2.00272 19.3
2 12.77880 2.43840
3 ∞ 8.51710 1.84666 23.8
4 ∞ 0.15000
5 * 12.07530 2.90120 1.69385 53.1
6 * -19.43760 Variable
7 * -13.20660 0.50000 1.77200 50.0
8 * 4.30020 0.60010
9 6.12960 1.14610 1.94595 18.0
10 11.83500 Variable
11 * 13.22100 1.15260 1.81000 41.0
12 -7.02210 0.01000 1.56732 42.8
13 -7.02210 0.30000 1.72825 28.3
14 56.59210 1.00000
15 (Aperture) ∞ Variable
16 * 5.78150 2.55090 1.51760 63.5
17 * -14.52750 0.12000
18 11.23090 3.89340 1.59282 68.6
19 -4.69070 0.01000 1.56732 42.8
20 -4.69070 0.77140 2.00100 29.1
21 5.20420 Variable
22 * 54.36630 2.33920 1.52996 55.8
23 * -5.79710 0.50000
24 ∞ 0.60000 1.51680 64.2
25 ∞ 0.37000
Image plane ∞

Table 11 (Aspheric data)

5th surface K = 0.00000E + 00, A4 = -1.10379E-04, A6 = -7.58116E-07, A8 = 2.12080E-08
A10 = -2.17300E-10, A12 = 0.00000E + 00, A14 = 0.00000E + 00
6th surface K = 0.00000E + 00, A4 = 4.11448E-05, A6 = -6.19577E-07, A8 = 2.88216E-08
A10 = -3.35617E-10, A12 = 0.00000E + 00, A14 = 0.00000E + 00
7th surface K = 0.00000E + 00, A4 = -1.55355E-04, A6 = 3.05392E-05, A8 = -1.37779E-06
A10 = 2.66649E-08, A12 = 0.00000E + 00, A14 = 0.00000E + 00
8th surface K = -8.75131E-01, A4 = -6.43005E-05, A6 = 4.28077E-05, A8 = -8.03509E-07
A10 = -3.45587E-09, A12 = 0.00000E + 00, A14 = 0.00000E + 00
11th surface K = 0.00000E + 00, A4 = -1.28454E-04, A6 = -3.70424E-06, A8 = 7.78067E-07
A10 = -1.63998E-07, A12 = 0.00000E + 00, A14 = 0.00000E + 00
16th surface K = 7.74219E-01, A4 = -5.39950E-04, A6 = -2.81182E-05, A8 = 2.74443E-06
A10 = -3.89462E-07, A12 = 1.60693E-08, A14 = 0.00000E + 00
17th surface K = 0.00000E + 00, A4 = 8.64892E-04, A6 = -1.99521E-05, A8 = 7.95379E-06
A10 = -9.71022E-07, A12 = 5.04694E-08, A14 = 0.00000E + 00
22nd surface K = 0.00000E + 00, A4 = 6.33384E-04, A6 = 1.76866E-04, A8 = -3.12044E-05
A10 = 2.81700E-06, A12 = -1.19783E-07, A14 = 2.01452E-09
23rd face K = 0.00000E + 00, A4 = 4.63863E-03, A6 = -2.83007E-04, A8 = 1.37042E-05
A10 = -1.71417E-07, A12 = 0.00000E + 00, A14 = 0.00000E + 00

Table 12 (various data)

Zoom ratio 4.69855
Wide angle Medium telephoto Focal length 4.5820 9.8677 21.5290
F number 4.04821 5.29652 6.48773
Angle of View 41.8161 21.2048 10.0533
Image height 3.4770 3.8920 3.8920
Total lens length 49.9390 49.9391 49.9391
d6 0.6483 4.7796 8.7047
d10 8.7064 4.5751 0.6500
d15 8.5553 5.5891 3.1998
d21 1.8586 4.8249 7.2142
Entrance pupil position 8.7977 12.3604 17.1413
Exit pupil position -44.1878-2867.4296 71.2474
Front principal point position 12.9051 22.1941 45.1718
Rear principal point position 45.4011 40.0775 28.3672

Single lens data Lens Start surface Focal length 1 1 -14.5728
2 3 ∞
3 5 11.1554
4 7 -4.1504
5 9 12.2457
6 11 5.8101
7 13 -8.5610
8 16 8.3477
9 18 6.1402
10 20 -2.3721
11 22 10.0197

Zoom lens group data Group Start surface Focal length Lens construction length Front principal point position Rear principal point position 1 1 14.41338 14.30670 10.32859 20.98416
2 7 -6.35041 2.24620 0.16249 0.99225
3 11 16.59194 2.46260 -0.05346 0.59657
4 16 19.18236 7.34570 -19.43101 -4.45387
5 22 10.01968 3.43920 1.40047 2.39430

Zoom lens group magnification group Start surface Wide angle Medium telephoto 1 1 0.00000 0.00000 0.00000
2 7 -0.45589 -0.64811 -1.08124
3 11 -6.48009 47.38009 10.88193
4 16 0.12595 -0.02598 -0.14709
5 22 0.85438 0.85818 0.86307

Table 13 below shows the corresponding values for each condition in the zoom lens system of each numerical example.

Table 13 (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 can be applied to digital input devices such as a digital camera, a camera of a portable information terminal such as a smartphone, a monitoring camera in a monitoring system, a Web camera, and an in-vehicle camera. In particular, the present disclosure is suitable for a photographing optical system that requires high image quality, such as a digital camera.

G1 1st lens group G2 2nd lens group G3 3rd lens group G4 4th lens group G5 5th lens group L1 1st lens element L2 2nd lens element (prism)
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 L10 10th lens element L11 11th lens element A Aperture stop P Parallel Flat plate S Image surface 1 Zoom lens system 2 Image sensor 3 Liquid crystal monitor 4 Case

Claims

From the object side to the image side,
A first lens group having positive power;
A second lens group having negative power;
A third lens group having positive power;
A fourth lens group,
The first lens group includes a lens element having a reflecting surface for bending light rays from an object,
During zooming from the wide-angle end to the telephoto end during imaging, the first lens group does not move along the optical axis, and the second lens group and the fourth lens group move along the optical axis,
A zoom lens system characterized by satisfying the following condition (1):
2.8 <L / (D 1 + D 2 ) <4.0 (1)
here,
L: total lens length (distance from the most object side lens surface of the first lens group to the image plane),
D 1 : the amount of movement of the second lens group during zooming from the wide-angle end to the telephoto end during imaging,
D 2 is the amount of movement of the fourth lens group during zooming from the wide-angle end to the telephoto end during imaging.
The zoom lens system according to claim 1, wherein the fourth lens group has positive power.
The zoom lens system according to claim 1, further comprising a fifth lens group immediately on the image side of the fourth lens group.
The zoom lens system according to claim 3, wherein the fifth lens group has a positive power.
The zoom lens system according to claim 1, wherein the second lens group includes two lens elements, and an air gap is provided between the two lens elements.
An imaging apparatus capable of outputting an optical image of an object as an electrical image signal,
A zoom lens system that forms an optical image of the object;
An image sensor that converts an optical image formed by the zoom lens system into an electrical image signal;
An imaging apparatus, wherein the zoom lens system is the zoom lens system according to claim 1.
A camera that converts an optical image of an object into an electrical image signal, and displays and stores the converted image signal;
An image pickup apparatus including a zoom lens system that forms an optical image of an object, and an image sensor that converts an optical image formed by the zoom lens system into an electrical image signal;
The camera according to claim 1, wherein the zoom lens system is the zoom lens system according to claim 1.