JP5928875B2 - Zoom lens, information device, and portable information terminal device - Google Patents

Description

  The present invention relates to a zoom lens having a zooming function that changes the angle of view by changing the focal length, a zoom lens suitable for an electronic still camera, a video camera, and the like, and such a zoom lens as a photographing optical system. The present invention relates to an information device and a portable information terminal device.

In recent years, zoom lenses have become common in photographic optical systems used in digital still cameras and the like. In particular, zoom lenses that include an angle of view of about 50 mm in a 35 mm size conversion in the focal length range are generally known. Further, in these zoom lenses, there are demands from users for downsizing, wide-angle, high speed autofocus (hereinafter referred to as AF), and the like.
As a configuration of this zoom lens, as a so-called positive lead type zoom lens having, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a subsequent group. For example, Japanese Patent Laid-Open No. 03-228008 (Patent Document 1), Japanese Patent No. 3716418 (Patent Document 2), Japanese Patent No. 3399686 (Patent Document 3), Japanese Patent No. 4401451 (Patent Document 4), This is disclosed in, for example, 2010-175594 (Patent Document 5).
The reason for adopting such a configuration is that the zoom ratio can be easily increased, and that the overall length can be reduced by the configuration of the front of the positive group.

Conventionally, as a focus method of these zoom lenses, an inner focus type in which a second lens group is moved as shown in Patent Document 1 or the like is known. In this system, the weight of the group to be moved is large during focusing, which increases the size of the motor and actuator and increases the maximum diameter of the lens barrel, as well as an automatic focusing operation (hereinafter referred to as “AF”). This is also disadvantageous in terms of speeding up of operation) and quieting during movie shooting.
As a method of reducing the weight of the focus group, a first lens group having a positive refractive power from the object side, a second lens group having a negative refractive power, a third lens group having a negative refractive power, and the subsequent Patent Document 2, Patent Document 3, Patent Document 4 and Patent Document 5 show a method of having a group and performing focusing with a third lens group.

However, in the zoom lenses disclosed in Patent Document 2, Patent Document 3 and Patent Document 4, it is difficult to say that the focus group is still lightweight, which is insufficient for the above-described user request.
On the other hand, Patent Document 5 shows a method using one negative lens as a focus group. By adopting such a method, the focus group can be reduced in weight and the AF speed and the lens barrel diameter can be reduced. However, the Abbe number and the refractive index range of the second lens group and the third lens group can be reduced. Therefore, the balance with other lens groups is lost, and there is room for improvement in downsizing, manufacturing error sensitivity, and aberration correction.
The present invention has been made in view of the above-described circumstances. The focus group is sufficiently compact, the focus group movement amount is small, the speed of the automatic focusing operation is increased, and the drive system required for the automatic focusing operation is reduced in size. It is small and high-performance, with a half field angle of 36.8 degrees or more at the wide-angle end, a zoom ratio of about 2.8 to 5 times, and a resolution corresponding to an image sensor exceeding 5 to 10 million pixels. An object of the present invention is to provide a zoom lens that can be realized, and to provide a small and high-performance information device and a portable information terminal device that use such a zoom lens as a photographing optical system. Yes.

In order to achieve the above-described object, the zoom lens according to the present invention provides
A first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having negative refractive power in order from the object side to the image side along the optical axis A fourth lens group having a positive refracting power and a fifth lens group having a positive refracting power, an aperture stop between the third lens group and the fourth lens group, and a wide angle During zooming from the end to the telephoto end, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group increases, and the third lens group And a distance between the fourth lens group is reduced, a distance between the fourth lens group and the fifth lens group is changed, and the zoom lens performs focusing by the third lens group,
The average Abbe number of the second lens group is νd2g, the average Abbe number of the third lens group is νd3g, the average refractive index of d-line of the second lens group is nd2g, and the d-line of the third lens group The average refractive index of nd3g,
The following conditional expressions (1) and (2):
(1) 15 <νd3g−νd2g <35
(2) 0.15 <nd2g-nd3g <0.35
It is characterized by satisfying.

According to the zoom lens according to the present invention,
A first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having negative refractive power in order from the object side to the image side along the optical axis A fourth lens group having a positive refracting power and a fifth lens group having a positive refracting power, an aperture stop between the third lens group and the fourth lens group, and a wide angle During zooming from the end to the telephoto end, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group increases, and the third lens group And a distance between the fourth lens group is reduced, a distance between the fourth lens group and the fifth lens group is changed, and the zoom lens performs focusing by the third lens group,
The average Abbe number of the second lens group is νd2g, the average Abbe number of the third lens group is νd3g, the average refractive index of d-line of the second lens group is nd2g, and the d-line of the third lens group The average refractive index of nd3g,
The following conditional expressions (1) and (2):
(1) 15 <νd3g−νd2g <35
(2) 0.15 <nd2g-nd3g <0.35
By satisfying
The focus group is sufficiently compact, the focus group movement is small, the speed of the autofocus operation can be further increased, and it is compact and high-performance with a half angle of view at the wide angle end of 36.8 degrees or more. It is possible to provide a zoom lens capable of realizing a resolving power corresponding to an imaging device having a ratio of about 2.8 to 5 times and exceeding 5 million to 10 million pixels. By using the lens as a photographic optical system, it is possible to further reduce the size of the drive system required for the automatic focusing operation and the resolution required for an image sensor with more than 10 million pixels. Thus, a small and high-performance information device and a portable information terminal device can be provided.

FIG. 2 is a cross-sectional view illustrating a configuration of an optical system of a zoom lens according to Embodiment 1 of the present invention and a zoom locus associated with zooming, in which (a) is a wide angle end, (b) is an intermediate focal length, and (c) is an intermediate focal length. It is sectional drawing along the optical axis in each in a telephoto end. FIG. 3 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the wide angle end of the zoom lens according to Embodiment 1 of the present invention shown in FIG. 1. FIG. 3 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the intermediate focal length of the zoom lens according to Example 1 of the present invention shown in FIG. 1. FIG. 3 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the telephoto end of the zoom lens according to Example 1 of the present invention shown in FIG. 1. FIG. 6 is a diagram illustrating a configuration of an optical system of a zoom lens according to Example 2 of the present invention and a zoom locus associated with zooming, where (a) is a wide angle end, (b) is an intermediate focal length, and (c) is a telephoto end. It is sectional drawing along the optical axis in each. FIG. 6 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the wide angle end of the zoom lens according to Embodiment 2 of the present invention shown in FIG. 5. FIG. 6 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the intermediate focal length of the zoom lens according to Example 2 of the present invention shown in FIG. 5. FIG. 6 is an aberration curve diagram showing spherical aberration, astigmatism, distortion aberration and coma aberration at the telephoto end of the zoom lens according to Embodiment 2 of the present invention shown in FIG. 5. FIG. 6 is a diagram illustrating a configuration of an optical system of a zoom lens according to Example 3 of the present invention and a zoom locus associated with zooming, in which (a) is a wide angle end, (b) is an intermediate focal length, and (c) is a telephoto end. It is sectional drawing along the optical axis in each. FIG. 10 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the wide-angle end of the zoom lens according to Example 3 illustrated in FIG. 9. FIG. 10 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the intermediate focal length of the zoom lens according to Example 3 illustrated in FIG. 9. FIG. 10 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the telephoto end of the zoom lens according to Embodiment 3 of the present invention shown in FIG. 9. FIG. 10 is a diagram illustrating the configuration of an optical system of a zoom lens according to Example 4 of the present invention and a zoom locus associated with zooming, where (a) is a wide angle end, (b) is an intermediate focal length, and (c) is a telephoto end. It is sectional drawing along the optical axis in each. FIG. 14 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the wide-angle end of the zoom lens according to Example 4 illustrated in FIG. 13. FIG. 14 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the intermediate focal length of the zoom lens according to Example 4 illustrated in FIG. 13. FIG. 14 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the telephoto end of the zoom lens according to Example 4 shown in FIG. 13. FIG. 10 is a diagram illustrating the configuration of an optical system of a zoom lens according to Example 5 of the present invention and a zoom locus associated with zooming, where (a) is a wide angle end, (b) is an intermediate focal length, and (c) is a telephoto end. It is sectional drawing along the optical axis in each. FIG. 18 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the wide-angle end of the zoom lens according to Example 5 illustrated in FIG. 17. FIG. 18 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration in the intermediate focal length of the zoom lens according to Example 5 illustrated in FIG. 17. FIG. 18 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the telephoto end of the zoom lens according to Example 5 illustrated in FIG. 17. FIG. 10 is a diagram illustrating a configuration of an optical system of a zoom lens according to Example 6 of the present invention and a zoom locus associated with zooming, where (a) is a wide angle end, (b) is an intermediate focal length, and (c) is a telephoto end. It is sectional drawing along the optical axis in each. FIG. 22 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the wide-angle end of the zoom lens according to Example 6 illustrated in FIG. 21. FIG. 22 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration in the intermediate focal length of the zoom lens according to Example 6 illustrated in FIG. 21. FIG. 22 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the telephoto end of the zoom lens according to Example 6 illustrated in FIG. 21. It is a figure which shows the structure of the optical system of the zoom lens which concerns on Example 7 of this invention, and the zoom locus | trajectory accompanying zooming, (a) is a wide angle end, (b) is an intermediate focal length, (c) is a telephoto end, It is sectional drawing along the optical axis in each. FIG. 26 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the wide-angle end of the zoom lens according to Example 7 illustrated in FIG. 25. FIG. 26 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the intermediate focal length of the zoom lens according to Example 7 illustrated in FIG. 25. FIG. 26 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the telephoto end of the zoom lens according to Example 7 illustrated in FIG. 25. FIG. 10 is a diagram illustrating a configuration of an optical system of a zoom lens according to Example 8 of the present invention and a zoom locus associated with zooming, where (a) is a wide angle end, (b) is an intermediate focal length, and (c) is a telephoto end. It is sectional drawing along the optical axis in each. FIG. 30 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the wide-angle end of the zoom lens according to Example 8 illustrated in FIG. 29. FIG. 30 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the intermediate focal length of the zoom lens according to Example 8 illustrated in FIG. 29. FIG. 30 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the telephoto end of the zoom lens according to Example 8 illustrated in FIG. 29. It is a figure which shows the structure of the optical system of the zoom lens based on Example 9 of this invention, and the zoom locus | trajectory accompanying zooming, (a) is a wide angle end, (b) is an intermediate focal length, (c) is a telephoto end, It is sectional drawing along the optical axis in each. FIG. 34 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the wide-angle end of the zoom lens according to Example 9 illustrated in FIG. 33. FIG. 34 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the intermediate focal length of the zoom lens according to Example 9 illustrated in FIG. 33. FIG. 34 is an aberration curve diagram showing spherical aberration, astigmatism, distortion and coma aberration at the telephoto end of the zoom lens according to Example 9 illustrated in FIG. 33. It is the perspective view seen from the to-be-photographed object side which shows typically the external appearance structure of the digital camera as an imaging device which concerns on the 10th Embodiment of this invention. It is the perspective view seen from the photographer side which shows typically the external appearance structure of the digital camera of FIG. FIG. 38 is a block diagram schematically illustrating a functional configuration of the digital camera in FIG. 37.

Hereinafter, based on an embodiment of the present invention, a zoom lens according to the present invention, an information device using the zoom lens, and a portable information terminal device will be described in detail with reference to the drawings.
Before describing specific examples, first, a fundamental embodiment of the present invention will be described.
Here, FIGS. 1, 5, 9, 13, 17, 21, 21, 25, 29, and 33 are respectively the first embodiment, the second embodiment, and the third embodiment. The fourth embodiment, the fifth embodiment, the sixth embodiment, the seventh embodiment, the eighth embodiment, and the ninth embodiment will be described later. As described above, Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, Example 7, Example 8, and Example 9 are also used.
In the zoom lenses according to the first to ninth embodiments of the present invention, the third lens group is used as a focus group, which not only speeds up AF and reduces noise by reducing the weight of the focus group. By reducing the amount of movement of the focus group, downsizing is simultaneously achieved. At the same time, by contributing to zooming, the degree of freedom in design is increased and further miniaturization and higher performance are achieved. In addition, the contribution of the fourth and fifth lens groups to zooming is increased, and each group corrects aberrations to increase the degree of freedom in design, resulting in further miniaturization. To improve performance. That is, since each group contributes to zooming, if the amount of aberration between the groups is not appropriate, the balance is lost, leading to an increase in aberrations and an increase in the size of the lens system.

The first to ninth embodiments of the present invention are embodiments as a zoom lens.
That is, the zoom lenses according to the first to ninth embodiments of the present invention are:
A first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having negative refractive power in order from the object side to the image side along the optical axis A fourth lens group having a positive refracting power and a fifth lens group having a positive refracting power, an aperture stop between the third lens group and the fourth lens group, and a wide angle During zooming from the end to the telephoto end, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group increases, and the third lens group And a distance between the fourth lens group is reduced, a distance between the fourth lens group and the fifth lens group is changed, and the zoom lens performs focusing by the third lens group,
The average Abbe number of the second lens group is νd2g, the average Abbe number of the third lens group is νd3g, the average refractive index of d-line of the second lens group is nd2g, and the d-line of the third lens group The average refractive index of nd3g,
The following conditional expressions (1) and (2):
(1) 15 <νd3g−νd2g <35
(2) 0.15 <nd2g-nd3g <0.35
Is satisfied (corresponding to claim 1).

The above conditional expressions (1) and (2) indicate appropriate Abbe numbers and refractive index ranges in the second lens group and the third lens group. If the range of conditional expressions (1) and (2) is exceeded, the amount of aberration such as chromatic aberration and curvature of field between the second lens group and the third lens group increases, and the fourth lens group and the fifth lens group Since the balance of aberration correction is lost, aberrations are increased. Further, if this is to be corrected, the size is increased and the sensitivity of manufacturing error increases, which is disadvantageous for productivity.
More preferably, the following formulas (1 ′) and (2 ′) are desirable.
(1 ′) 18 <νd3g−νd2g <32
(2 ') 0.2 <nd2g-nd3g <0.3
In order to achieve higher performance, it is desirable to satisfy the following conditional expression (3) (corresponding to claim 2).
That is, the focal length of the fourth lens group is F3, the focal length at the wide-angle end is Fw, the focal length at the telephoto end is Ft, and the intermediate focal length Fm is Fm = √ (Fw × Ft). As the following conditional expression (3):
(3) 1.0 <| F3 / Fm | <2.5
It is desirable to satisfy

Conditional expression (3) is a conditional expression showing an appropriate focal length range of the third lens group. If the lower limit value of conditional expression (3) is not reached, the power of the group increases, which is advantageous for miniaturization, but increases the sensitivity of eccentricity error. If the upper limit is exceeded, the eccentricity sensitivity is lowered, but it is disadvantageous for downsizing. In addition, satisfying the conditional expressions (1) and (2) at the same time makes it possible to balance the aberrations between the groups and to improve the performance.
In order to achieve higher performance, it is desirable to satisfy the following conditional expressions (4) and (5) (corresponding to claim 3).
That is, when the average Abbe number of the second lens group is νd2g, the average Abbe number of the fourth lens group is νd4g, and the average Abbe number of the fifth lens group is νd5g, the following conditional expressions (4), ( 5):
(4) 10 <νd4g−νd2g <25
(5) 5 <νd5g−νd2g <20
It is desirable to satisfy
Conditional expressions (4) and (5) are conditional expressions showing appropriate ranges of the average Abbe numbers of the lenses constituting the fourth lens group and the fifth lens group, respectively. By satisfying the conditional expressions (1) and (2) simultaneously, the aberrations in each lens group are balanced, which is advantageous not only for high performance but also for miniaturization.

More preferably, the following formula is desirable.
(4 ′) 12 <νd4g−νd2g <22
(5 ′) 10 <νd5g−νd2g <16
In order to further improve the performance, it is desirable that the third lens group is composed of one negative lens (corresponding to claim 4).
By making the third lens group a single negative lens, the weight of the focus group can be reduced, which is advantageous for speeding up focusing and reducing noise.
In order to achieve higher performance, it is desirable that all the lens groups move during zooming (corresponding to claim 5).
Since all the lens groups contribute to zooming, the burden on each group is reduced, which not only is advantageous in terms of aberration correction and workability, but also efficiently reduces the amount of movement of the first lens group. This is advantageous for downsizing.
In the zoom lens, it is preferable that the following conditional expression is satisfied (corresponding to claim 6).

That is, the following conditional expressions (6) and (7) are given, where Fw is the focal length at the wide-angle end, Ft is the focal length at the telephoto end, and Y ′ is the image height.
(6) 0.75 <Y ′ / Fw
(7) 2.8 <Ft / Fw
It is desirable to satisfy
Conditional expression (6) regulates the angle of view, and a high-performance and compact zoom lens having a half angle of view of 36.8 degrees or more at the wide-angle end can be obtained. Here, conditional expression (7) regulates the zoom ratio, and a high-performance, wide-angle and compact zoom lens can be obtained with a zoom ratio of 2.8 times or more.
More preferably, it is desirable to satisfy the following conditional expressions (6 ′) and (7 ′): (6 ′) 0.87 <Y ′ / Fw
(7 ') 2.8 <Ft / Fw <5
The aperture diameter of the aperture may be simplified due to the mechanism of “constant regardless of zooming”, but by changing the aperture diameter at the telephoto end compared to the wide-angle end, the change in the F number is reduced. You can also. When it is necessary to reduce the amount of light that reaches the image plane, the aperture may be made smaller, but reducing the amount of light by inserting an ND filter or the like without greatly changing the aperture diameter reduces the resolving power due to the diffraction phenomenon. Is more preferable.

In the present invention, a five-group configuration is used. By increasing the number of subsequent groups of the third lens group, which is the focus group, and moving during zooming, the burden on zooming of the front group is reduced and the degree of freedom is increased, which is advantageous in terms of aberration correction and workability. However, this is a trade-off with downsizing of the optical system, and it is appropriate to use the fourth lens group having positive refractive power and the fifth lens group having positive refractive power. In addition, the four-group configuration is advantageous for downsizing, but the degree of design freedom is reduced correspondingly, which is disadvantageous in terms of aberration correction, and the five-group configuration is appropriate.
An information device according to the present invention is an information device having a photographing function characterized by having the zoom lens as a photographing optical system (corresponding to claim 7). This information device has a photographing function characterized in that an object image by a zoom lens is formed on a light receiving surface of an image sensor (corresponding to claim 8). As described above, the information device can be implemented as a digital camera, a video camera, a silver salt camera, or the like, but can be suitably implemented as a portable information terminal device (corresponding to claim 9).
The zoom lens according to the present invention has a configuration as described above, the focus group is sufficiently compact, the focus group movement is small, a small size and high performance, a half angle of view at the wide angle end of 36.8 degrees or more, and a zoom ratio is high. 2.8 times to 5 times, sufficiently small aberration, small size, and a zoom lens that has a resolution corresponding to an image sensor with more than 5 to 10 million pixels as an imaging optical system. A good shooting function can be realized.

The above description is common to the zoom lenses according to the first to ninth embodiments.
The tenth embodiment of the present invention is an embodiment of an information device such as a so-called digital camera or video camera, or a portable information terminal device such as a mobile phone, which will be described in detail later.
Next, examples based on specific numerical values based on the above-described first to ninth embodiments of the present invention will be described in detail.
Examples 1 to 9 described below are examples of specific configurations based on numerical examples of the zoom lenses according to the first to ninth embodiments of the present invention, respectively. 1 to 4 are diagrams for explaining a zoom lens in Example 1 according to the first embodiment of the present invention, and FIGS. 5 to 8 illustrate the second embodiment of the present invention. FIG. 9 to FIG. 12 are for explaining the zoom lens in Example 3 according to the third embodiment of the present invention. FIGS. 13 to 16 are for explaining a zoom lens in Example 4 according to the fourth embodiment of the present invention, and FIGS. 17 to 20 are related to the fifth embodiment of the present invention. FIG. 21 to FIG. 24 are for explaining the zoom lens in Example 6 according to the sixth embodiment of the present invention, and FIG. FIG. 28 shows an implementation according to the seventh embodiment of the present invention. FIG. 29 to FIG. 32 are for explaining the zoom lens in Example 8 according to the eighth embodiment of the present invention, and FIG. FIG. 36 is a diagram for explaining a zoom lens in Example 9 according to the ninth embodiment of the present invention.

In the zoom lenses according to the first to ninth embodiments, the optical element formed of a parallel plate disposed on the image plane side of the fifth lens group includes various optical filters such as an optical low-pass filter and an infrared cut filter. In addition, it is assumed to be a cover glass (seal glass) of a light receiving image pickup device such as a CMOS (complementary metal oxide semiconductor) image sensor or a CCD (charge coupled device) image sensor, and is shown as an equivalent transparent parallel plate. , And so on.
In the first to ninth embodiments, some lens surfaces are aspherical. In order to form an aspherical surface, each lens surface is directly aspherical like a so-called molded aspherical lens, and a resin that forms an aspherical surface on the lens surface of a spherical lens like a so-called hybrid aspherical lens. There is a configuration in which an aspheric surface is obtained by laying a thin film, any of which may be used.
Aberrations in the zoom lenses according to the first to ninth embodiments are sufficiently corrected, and can correspond to light receiving elements having more than 5 to 10 million pixels. By configuring the zoom lens according to the first to ninth embodiments of the present invention, it is possible to increase the speed of the automatic focusing (AF) operation and to reduce the size of the drive system required for the automatic focusing (AF) operation. In addition, it is clear from Examples 1 to 9 that very good image performance can be secured while achieving sufficient size reduction.

The meanings of symbols common to Examples 1 to 9 are as follows.
f: Focal length of the entire optical system F: F number (F value)
ω: Half angle of view (degrees)
R: radius of curvature (paraxial radius of curvature for aspheric surfaces)
D: surface interval Nd: refractive index [nu] d: Abbe number K: aspherical conic constant A _4: 4-order aspherical constants A _6: 6-order aspherical constants A _8: 8-order aspherical constants A _10: 10 The following aspheric constant A ₁₂ : 12th order aspheric constant A ₁₄ : 14th order aspheric constant The aspherical shape used here is the reciprocal of the paraxial radius of curvature (paraxial curvature) from the optical axis. The height is H, the conic constant is K, the aspherical coefficient of each order described above is used, and X is the aspherical amount in the optical axis direction, which is defined by the following equation (8). The shape is specified by giving a constant and an aspheric coefficient.

で表されるものであり、近軸曲率半径と円錐定数、非球面係数を与えて形状を特定する。

The shape is specified by giving a paraxial radius of curvature, a conic constant, and an aspherical coefficient.

FIG. 1 schematically shows the lens configuration of the optical system of the zoom lens of Example 1 according to the first embodiment of the present invention and the zoom locus associated with zooming from the wide-angle end to the telephoto end through a predetermined intermediate focal length. (A) is a sectional view at a short focal end, that is, a wide angle end, (b) is a sectional view at a predetermined intermediate focal length, and (c) is a sectional view at a long focal end, that is, a telephoto end . In FIG. 1 showing the lens group arrangement of Example 1, the left side in the figure is the object (subject) side, and the right side is the image side.
The zoom lens shown in FIG. 1 includes, in order from the object side along the optical axis, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a negative refractive power. A third lens group G3 having a positive refractive power, a fifth lens group G5 having a positive refractive power, and a third lens group G3 and a fourth lens group. An aperture stop AD is disposed between G4 and G4.
The first lens group G1 includes a first lens L1 and a second lens L2 sequentially from the object side. The second lens group G2 includes a third lens L3 and a fourth lens L4 sequentially from the object side. And the fifth lens L5, the third lens group G3 includes a single sixth lens L6, and the fourth lens group G4 sequentially includes, from the object side, the seventh lens L7, The eighth lens L8 and the ninth lens L9 are arranged, and the fifth lens group G5 is formed by sequentially arranging the tenth lens L10 and the eleventh lens L11 from the object side.

The first lens group G1 to the fifth lens group G5 are each supported by a common support frame or the like appropriate for each group, and operate integrally for each group during zooming or the like. FIG. 1 also shows the surface numbers of the optical surfaces. Note that each reference symbol in FIG. 1 is used independently for each embodiment in order to avoid complication of explanation due to an increase in the number of digits of the reference symbol. Therefore, a reference symbol common to the drawings according to the other embodiments. Even if attached, they are not necessarily a common configuration with other embodiments.
With the zooming from the wide-angle end (short focal end) to the telephoto end (long focal end), the entire first lens group G1 to fifth lens group G5 move to move the first lens group G1 and the second lens group G1. The distance between the lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 increases, the distance between the third lens group G3 and the fourth lens group G4 decreases, and the fourth lens The distance between the group G4 and the fifth lens group G5 decreases. The aperture stop AD operates integrally with the fourth lens group G4.
The first lens group G1 includes, in order from the object side, a first lens L1 composed of a negative meniscus lens having a convex surface facing the object side, and a second lens L2 composed of a positive meniscus lens having a convex surface facing the object side. doing. The two lenses of the first lens L1 and the second lens L2 are closely bonded to each other and are integrally joined to form a cemented lens composed of two lenses.

The second lens group G2 is composed of a third lens L3 composed of a negative meniscus lens having a convex surface directed toward the object side in order from the object side, and a biconcave lens in which aspherical surfaces are formed on both surfaces with a stronger concave surface directed toward the image side. A fourth lens L4 and a fifth lens L5 composed of a biconvex lens having a stronger convex surface on the object side are arranged.
The third lens group G3 includes a single sixth lens L6 made of a negative meniscus lens having a strong concave surface facing the object side.
The aperture stop AD is interposed between the third lens group G3 and the fourth lens group G4 and operates integrally with the fourth lens group G4 as described above.
The fourth lens group G4 is composed of, from the object side, a seventh lens L7, which is a biconvex lens in which a strong convex surface is directed toward the object side and aspheric surfaces are formed on both surfaces, and a biconvex lens having a strong convex surface toward the image side. An eighth lens L8 and a ninth lens L9 made of a biconcave lens having a stronger concave surface on the object side are arranged. The two lenses of the eighth lens L8 and the ninth lens L9 are closely bonded to each other and joined together to form a cemented lens composed of two lenses.

The fifth lens group G5 includes, from the object side, a tenth lens L10 including a biconvex lens in which a slightly strong convex surface is directed toward the object side and aspheric surfaces are formed on both surfaces, and a negative meniscus lens having a convex surface directed toward the object side 11th lens L11 which consists of.
In this case, as shown in FIG. 1, the first lens group G1 moves substantially monotonously from the image side to the object side with zooming from the wide-angle end (short focal end) to the telephoto end (long focal end). The second lens group G2 moves from the image side to the object side, the third lens group G3 moves from the image side to the object side, and the aperture stop AD and the fourth lens group G4 generally move from the image side to the object side. The fifth lens group G5 moves from the image side to the object side.
In Example 1, the focal length f, F number F, and half angle of view ω of the entire optical system are f = 16.146 to 53.852, F = 3.59 to 5.93, and ω, respectively, by zooming. = 41.53 to 14.87. The optical characteristics of the optical elements in Example 1 are as shown in Table 1 below.

In Table 1, the lens surface with the surface number indicated by adding “* (asterisk)” to the surface number is an aspherical surface. The same applies to the other embodiments.
That is, in Table 1, the sixth surface, the seventh surface, the thirteenth surface, the fourteenth surface, the eighteenth surface, and the nineteenth surface with “*” are aspherical surfaces, and the formula [8 The parameters (aspheric coefficient) of each aspheric surface in] are as follows. In the aspheric parameter, “En” represents “power of 10”, that is, “× 10 ⁿ ”, for example, “E-05” represents “× 10 ⁻⁵ ”. The same applies to the other embodiments.
Aspherical parameter 6th surface K = 0
A ₄ = −1.12571E−05
A ₆ = 1.21899E-07
A ₈ = 2.76874E-09
A ₁₀ = −4.5160E-11
A ₁₂ = 1.38009E-13
The seventh side K = 0
A ₄ = -4.98762E-05
A ₆ = 3.02710E-07
A ₈ = −1.833352E-09
A ₁₀ = −4.95535E-12

13th surface K = 0
A ₄ = −2.23034E-05
A ₆ = −3.30061E−08
A ₈ = 1.96596E-09
A ₁₀ = -4.33079E-11
14th surface K = 0
A ₄ = −6.886789E-06
A ₆ = 1.59127E-07
A ₈ = -8.05125E-10
A ₁₀ = −2.46291E-11

18th surface K = -4.776959
A ₄ = −2.06414E-06
A ₆ = −1.71695E-07
A ₈ = −2.333143E-09
A ₁₀ = 6.08643E-12
19th surface K = 0.50443
A ₄ = 3.72591E-05
A ₆ = −4.111291E-08
A ₈ = −2.02648E-09
A ₁₀ = 3.886766E-12
In the first embodiment, the focal length f of the entire optical system, the variable distance DA between the first lens group G1 and the second lens group G2, and the variable distance between the second lens group G2 and the third lens group G3. The distance DB, the variable distance DC between the third lens group G3 and the aperture stop AD, the variable distance DD between the fourth lens group G4 and the fifth lens group G5, the fifth lens group G5 and the filter FG, etc. The variable interval such as the variable interval DE is changed as shown in the following Table 2 with zooming.

In the zoom lens of Example 1 described above, the values in the conditional expressions (1) to (7) described above are as shown in the column of Example 1 in Table 19 below.
In the zoom lens of Example 1 described above, the values of the parameters related to conditional expressions (1) to (7) are all within the range of the conditional expressions.
2, FIG. 3, and FIG. 4 show aberration diagrams of spherical aberration, astigmatism, distortion, and coma aberration at the wide-angle end, the intermediate focal length, and the telephoto end, respectively, of Example 1. In each of these aberration diagrams, the broken line in the spherical aberration diagram represents the sine condition, the solid line in the astigmatism diagram represents the sagittal, and the broken line represents the meridional. In addition, “g” and “d” represent the g line and the d line, respectively. The same applies to the aberration diagrams of the other examples.

FIG. 5 schematically shows the lens configuration of the optical system of the zoom lens of Example 2 according to the second embodiment of the present invention and the zoom locus accompanying zooming from the wide-angle end to the telephoto end through a predetermined intermediate focal length. (A) is a cross-sectional view at a short focal end, that is, a wide-angle end, (b) is a cross-sectional view at a predetermined intermediate focal length, and (c) is a cross-sectional view at a long focal end, that is, a telephoto end. . In FIG. 5 showing the arrangement of the lens groups of Example 2, the left side in the drawing is the object (subject) side.
The zoom lens shown in FIG. 5 includes a first lens group G1 having a positive refractive power and a second lens group G2 having a negative refractive power in order from the object side to the image side along the optical axis. A third lens group G3 having a negative refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a positive refractive power, and a third lens group G3. And the fourth lens group G4 are arranged with an aperture stop AD.
The first lens group G1 includes a first lens L1 and a second lens L2 sequentially from the object side. The second lens group G2 includes a third lens L3 and a fourth lens L4 sequentially from the object side. And the fifth lens L5, the third lens group G3 includes a single sixth lens L6, and the fourth lens group G4 sequentially includes, from the object side, the seventh lens L7, The eighth lens L8 and the ninth lens L9 are arranged, and the fifth lens group G5 is formed by sequentially arranging the tenth lens L10 and the eleventh lens L11 from the object side.

The first lens group G1 to the fifth lens group G5 are each supported by a common support frame or the like appropriate for each group, and operate integrally for each group during zooming or the like. FIG. 5 also shows the surface numbers of the optical surfaces. In addition, in order to avoid complication of explanation due to an increase in the number of digits of the reference code, each reference code in FIG. 5 is used independently for each embodiment. Therefore, the same reference numerals as those in the drawings according to the other embodiments are used. Even if attached, they are not necessarily a common configuration with other embodiments.
With the zooming from the wide-angle end (short focal end) to the telephoto end (long focal end), the entire first lens group G1 to fifth lens group G5 move to move the first lens group G1 and the second lens group G1. The distance between the lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 increases, the distance between the third lens group G3 and the fourth lens group G4 decreases, and the fourth lens The distance between the group G4 and the fifth lens group G5 decreases. The aperture stop AD operates integrally with the fourth lens group G4.
The first lens group G1 includes, in order from the object side, a first lens L1 composed of a negative meniscus lens having a convex surface facing the object side, and a second lens L2 composed of a positive meniscus lens having a convex surface facing the object side. doing. The two lenses of the first lens L1 and the second lens L2 are closely bonded to each other and are integrally joined to form a cemented lens composed of two lenses.

The second lens group G2 is composed of a third lens L3 composed of a negative meniscus lens having a convex surface directed toward the object side in order from the object side, and a biconcave lens in which aspherical surfaces are formed on both surfaces with a stronger concave surface directed toward the object side. A fourth lens L4 and a fifth lens L5 composed of a biconvex lens having a stronger convex surface on the image side are arranged.
The third lens group G3 includes a single sixth lens L6 including a negative meniscus lens having a concave surface directed toward the object side.
The aperture stop AD is interposed between the third lens group G3 and the fourth lens group G4 and operates integrally with the fourth lens group G4 as described above.
The fourth lens group G4 is composed of, from the object side, a seventh lens L7, which is a biconvex lens in which a strong convex surface is directed toward the object side and aspheric surfaces are formed on both surfaces, and a biconvex lens having a strong convex surface toward the image side. An eighth lens L8 and a ninth lens L9 made of a biconcave lens having a stronger concave surface on the object side are arranged. The two lenses of the eighth lens L8 and the ninth lens L9 are closely bonded to each other and joined together to form a cemented lens composed of two lenses.

The fifth lens group G5 is composed of a tenth lens L10, which is a biconvex lens in which an aspheric surface is formed on both sides of the object side, and a negative meniscus lens having a convex surface on the object side. An eleventh lens L11 is disposed.
In this case, as shown in FIG. 5, the first lens group G1 moves from the image side to the object side almost monotonously with zooming from the wide-angle end (short focal end) to the telephoto end (long focal end). The second lens group G2 moves from the image side to the object side, the third lens group G3 moves from the image side to the object side, and the aperture stop AD and the fourth lens group G4 generally move from the image side to the object side. The fifth lens group G5 moves from the image side to the object side.
In Example 2, the focal length f, F number F, and half angle of view ω of the entire optical system are f = 16.146 to 53.851, F = 3.6 to 5.77, and ω by zooming, respectively. = 41.53 to 14.87. The optical characteristics of each optical element in Example 2 are as shown in the following table.

In Table 3, the lens surface with the surface number indicated by adding “*” to the surface number is an aspherical surface. The same applies to the other embodiments.
That is, in Table 3, the optical surfaces of the sixth surface, the seventh surface, the thirteenth surface, the fourteenth surface, the eighteenth surface, and the nineteenth surface marked with “*” are aspherical surfaces. The parameters (aspheric coefficients) of each aspheric surface in () are as follows. In the aspheric parameter, “En” represents “power of 10”, that is, “× 10 ⁿ ”, for example, “E-05” represents “× 10 ⁻⁵ ”. The same applies to the other embodiments.
Aspherical parameter 6th surface K = 0
A ₄ = −6.193912E-05
A ₆ = 6.02764E-07
A ₈ = −3.692727-09
A ₁₀ = −5.86282E-12

The seventh side K = 0
A ₄ = −9.55571E−05
A ₆ = 6.67024E-07
A ₈ = −5.778157E-09
A ₁₀ = 3.44512E-12
13th surface K = 0
A ₄ = −2.21195E−05
A ₆ = −1.07672E-06
A ₈ = 1.98544E-08
A ₁₀ = −3.47093E-10
14th surface K = 0
A ₄ = 5.12674E-06
A ₆ = −9.94310E−07
A ₈ = 1.53589E-08
A ₁₀ = _-2.78900E-10

18th surface K = -1.2879
A ₄ = −1.577778E-05
A ₆ = −7.80973E−08
A ₈ = −8.669905E-10
A ₁₀ = 3.89552E-12
19th surface K = 0.98584
A ₄ = 4.43195E-05
A ₆ = 5.66872E-08
A ₈ = −2.664609E-09
A ₁₀ = 1.33387E-11
In Example 2, the focal length f of the entire optical system, the variable distance DA between the first lens group G1 and the second lens group G2, and the variable distance between the second lens group G2 and the third lens group G3. The distance DB, the variable distance DC between the third lens group G3 and the aperture stop AD, the variable distance DD between the fourth lens group G4 and the fifth lens group G5, the fifth lens group G5 and the filter FG, etc. The variable interval such as the variable interval DE is changed as shown in the following Table 4 with zooming.

Each value in conditional expression (1) to conditional expression (7) in the above-described second embodiment is as shown in the column of the second embodiment in Table 19 below.
In the zoom lens of Example 2 described above, the values of the parameters related to the conditional expressions (1) to (7) described above are all within the range of the conditional expressions.
6, FIG. 7 and FIG. 8 show aberration diagrams of spherical aberration, astigmatism, distortion aberration, and coma aberration at the wide-angle end, intermediate focal length, and telephoto end, respectively, of Example 2. In each of these aberration diagrams, the broken line in the spherical aberration diagram represents the sine condition, the solid line in the astigmatism diagram represents the sagittal, and the broken line represents the meridional. In addition, “g” and “d” represent the g line and the d line, respectively. The same applies to the aberration diagrams of the other examples.

FIG. 9 schematically shows the lens configuration of the zoom lens optical system of Example 3 according to the third embodiment of the present invention and the zoom locus associated with zooming from the wide-angle end to the telephoto end through a predetermined intermediate focal length. (A) is a cross-sectional view at a short focal end, that is, a wide-angle end, (b) is a cross-sectional view at a predetermined intermediate focal length, and (c) is a cross-sectional view at a long focal end, that is, a telephoto end. . In FIG. 9 showing the lens group arrangement of Example 3, the left side in the drawing is the object (subject) side.
The zoom lens shown in FIG. 9 includes, in order from the object side along the optical axis, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a negative refractive power. A third lens group G3 having a positive refractive power, a fifth lens group G5 having a positive refractive power, and a third lens group G3 and a fourth lens group. An aperture stop AD is disposed between G4 and G4.
The first lens group G1 includes a first lens L1 and a second lens L2 sequentially from the object side. The second lens group G2 includes a third lens L3 and a fourth lens L4 sequentially from the object side. And the fifth lens L5, the third lens group G3 includes a single sixth lens L6, and the fourth lens group G4 sequentially includes, from the object side, the seventh lens L7, The eighth lens L8 and the ninth lens L9 are arranged, and the fifth lens group G5 is formed by sequentially arranging the tenth lens L10 and the eleventh lens L11 from the object side.

The first lens group G1 to the fifth lens group G5 are each supported by a common support frame or the like appropriate for each group, and operate integrally for each group during zooming or the like.
With the zooming from the wide-angle end (short focal end) to the telephoto end (long focal end), the entire first lens group G1 to fifth lens group G5 move to move the first lens group G1 and the second lens group G1. The distance between the lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 increases, the distance between the third lens group G3 and the fourth lens group G4 decreases, and the fourth lens The distance between the group G4 and the fifth lens group G5 decreases. The aperture stop AD operates integrally with the fourth lens group G4.
The first lens group G1 is composed of a first lens L1 composed of a negative meniscus lens having a convex surface facing the object side and a second meniscus lens composed of a positive meniscus lens having a convex surface facing the object side. A lens L2 is disposed. The two lenses of the first lens L1 and the second lens L2 are closely bonded to each other and are integrally joined to form a cemented lens composed of two lenses.
The second lens group G2 is composed of a third lens L3 composed of a negative meniscus lens having a convex surface directed toward the object side in order from the object side, and a biconcave lens in which aspherical surfaces are formed on both surfaces with a stronger concave surface directed toward the image side. A fourth lens L4 and a fifth lens L5 composed of a biconvex lens having a stronger convex surface on the image side are arranged.

The third lens group G3 includes a single sixth lens L6 including a negative meniscus lens having a concave surface directed toward the object side.
The aperture stop AD is interposed between the third lens group G3 and the fourth lens group G4 and operates integrally with the fourth lens group G4 as described above.
The fourth lens group G4 is composed of, from the object side, a seventh lens L7, which is a biconvex lens in which a strong convex surface is directed toward the object side and aspheric surfaces are formed on both surfaces, and a biconvex lens having a strong convex surface toward the image side. An eighth lens L8 and a ninth lens L9 made of a biconcave lens with a slightly strong concave surface facing the image side are arranged. The two lenses of the eighth lens L8 and the ninth lens L9 are closely bonded to each other and joined together to form a cemented lens composed of two lenses.

The fifth lens group G5 is composed of a tenth lens L10, which is a biconvex lens in which an aspheric surface is formed on both sides of the object side, and a negative meniscus lens having a convex surface on the object side. An eleventh lens L11 is disposed.
In this case, as shown in FIG. 9, the first lens group G1 moves from the image side to the object side almost monotonously with zooming from the wide-angle end (short focal end) to the telephoto end (long focal end). The second lens group G2 moves from the image side to the object side, the third lens group G3 moves from the image side to the object side, and the aperture stop AD and the fourth lens group G4 generally move from the image side to the object side. The fifth lens group G5 moves from the image side to the object side.
In Example 3, the focal length f, F number F, and half angle of view ω of the entire optical system are f = 16.146 to 53.85, F = 3.62 to 5.67, and ω by zooming, respectively. = 41.53 to 14.87. The optical characteristics of the optical elements in Example 3 are as shown in Table 5 below.

In Table 5, the lens surface with the surface number indicated by adding “*” to the surface number is an aspherical surface.
That is, in Table 5, the optical surfaces of the sixth surface, the seventh surface, the thirteenth surface, the fourteenth surface, the eighteenth surface, and the nineteenth surface marked with “*” are aspheric surfaces, and the formula (8 The parameters (aspheric coefficients) of each aspheric surface in () are as follows.
Aspherical parameter 6th surface K = 0
A ₄ = −8.181151E-06
A ₆ = −2.01833E-07
A ₈ = 2.53333E-09
A ₁₀ = -1.29107E-11

The seventh side K = 0
A ₄ = −3.223283E-05
A ₆ = −1.88341E-07
A ₈ = 1.96755E-09
A ₁₀ = −1.43273E-11
13th surface K = 0
A ₄ = −3.2004E-05
A ₆ = -9.60992E-07
A ₈ = 1.55589E-08
A ₁₀ = −2.82657E−10
14th surface K = 0
A ₄ = 3.53815E-06
A ₆ = −8.66214E-07
A ₈ = 1.17377E-08
A ₁₀ = −2.22442E−10

18th surface K = -1.25337
A ₄ = −1.58768E−05
A ₆ = −1.866624E-07
A ₈ = 6.94712E-10
A ₁₀ = −5.997184E-12
19th face K = 0
A ₄ = 3.31640E-05
A ₆ = −1.06067E-07
A ₈ = −6.292723E-10
A ₁₀ = 0
In Example 3, the focal length f of the entire optical system, the variable distance DA between the first lens group G1 and the second lens group G2, and the variable distance between the second lens group G2 and the third lens group G3. The distance DB, the variable distance DC between the third lens group G3 and the aperture stop AD, the variable distance DD between the fourth lens group G4 and the fifth lens group G5, the fifth lens group G5 and the filter FG, etc. The variable interval such as the variable interval DE is changed as shown in the following Table 6 with zooming.

In the zoom lens of Example 3 described above, the values in the conditional expressions (1) to (7) described above are as shown in the column of Example 3 in Table 19 below.
In the zoom lens of Example 3 described above, the values of the conditional expressions (1) to (7) are all within the range of the conditional expressions.
10, 11, and 12 show aberration diagrams of spherical aberration, astigmatism, distortion, and coma aberration at the wide-angle end, the intermediate focal length, and the telephoto end of Example 3, respectively. In each of these aberration diagrams, the broken line in the spherical aberration diagram represents the sine condition, the solid line in the astigmatism diagram represents the sagittal, and the broken line represents the meridional. In addition, “g” and “d” represent the g line and the d line, respectively.

FIG. 13 schematically shows the lens configuration of the zoom lens optical system of Example 4 according to the fourth embodiment of the present invention and the zoom locus associated with zooming from the wide-angle end to the telephoto end through a predetermined intermediate focal length. (A) is a sectional view at a short focal end, that is, a wide-angle end, (b) is a sectional view at a predetermined intermediate focal length, and (c) is a sectional view at a long focal end, that is, a telephoto end. . In FIG. 13 showing the arrangement of the lens groups in Example 4, the left side is the object (subject) side.
The zoom lens shown in FIG. 13 includes, in order from the object side along the optical axis, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a negative refractive power. A third lens group G3 having a positive refractive power, a fifth lens group G5 having a positive refractive power, and a third lens group G3 and a fourth lens group. An aperture stop AD is disposed between G4 and G4.
The first lens group G1 includes a first lens L1 and a second lens L2 sequentially from the object side. The second lens group G2 includes a third lens L3 and a fourth lens L4 sequentially from the object side. And the fifth lens L5, the third lens group G3 includes a single sixth lens L6, and the fourth lens group G4 sequentially includes, from the object side, the seventh lens L7, The eighth lens L8 and the ninth lens L9 are arranged, and the fifth lens group G5 is formed by sequentially arranging the tenth lens L10 and the eleventh lens L11 from the object side.

The first lens group G1 to the fifth lens group G5 are each supported by a common support frame or the like appropriate for each group, and operate integrally for each group during zooming or the like.
With the zooming from the wide-angle end (short focal end) to the telephoto end (long focal end), the entire first lens group G1 to fifth lens group G5 move to move the first lens group G1 and the second lens group G1. The distance between the lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 increases, the distance between the third lens group G3 and the fourth lens group G4 decreases, and the fourth lens The distance between the group G4 and the fifth lens group G5 decreases. The aperture stop AD operates integrally with the fourth lens group G4.
The first lens group G1 includes, in order from the object side, a first lens L1 composed of a negative meniscus lens having a convex surface facing the object side, and a second lens L2 composed of a positive meniscus lens having a convex surface facing the object side. doing. The two lenses of the first lens L1 and the second lens L2 are closely bonded to each other and are integrally joined to form a cemented lens composed of two lenses.
The second lens group G2 is composed of a third lens L3 composed of a negative meniscus lens having a convex surface directed toward the object side in order from the object side, and a biconcave lens in which aspherical surfaces are formed on both surfaces with a stronger concave surface directed toward the image side. A fourth lens L4 and a fifth lens L5 made of a biconvex lens with convex surfaces having the same curvature facing both sides are arranged.

The third lens group G3 includes a single sixth lens L6 made of a negative meniscus lens having a strong concave surface facing the object side.
The aperture stop AD is interposed between the third lens group G3 and the fourth lens group G4 and operates integrally with the fourth lens group G4 as described above.
The fourth lens group G4 includes, from the object side, a seventh lens L7, which is a biconvex lens having an aspheric surface on both sides with a strong convex surface facing the object side, and a biconvex lens with a strong convex surface facing the object side. An eighth lens L8 and a ninth lens L9 made of a biconcave lens having a stronger concave surface on the image side are arranged. The two lenses of the eighth lens L8 and the ninth lens L9 are closely bonded to each other and joined together to form a cemented lens composed of two lenses.
The fifth lens group G5 is composed of a tenth lens L10, which is a biconvex lens in which an aspheric surface is formed on both sides, and a negative meniscus lens having a convex surface facing the image side. An eleventh lens L11 is disposed.

This fourth embodiment is different from the other embodiments in that the negative meniscus lens of the eleventh lens L11 of the fifth lens group G5 has a convex surface facing the image side.
In Example 4, the focal length f, F number F, and half angle of view ω of the entire optical system are f = 16.146 to 53.852, F = 3.68 to 5.97, and ω, respectively, by zooming. = 41.53 to 14.87. The optical characteristics of the optical elements in Example 4 are as shown in Table 7 below.

In Table 7, the lens surface with the surface number indicated by adding “*” to the surface number is an aspherical surface. The same applies to the other embodiments.
That is, in Table 7, the optical surfaces of the sixth surface, the seventh surface, the thirteenth surface, the fourteenth surface, the eighteenth surface, and the nineteenth surface marked with “*” are aspheric surfaces, and the formula (8 ), Parameters of each aspheric surface (aspheric coefficient) are as follows.
Aspheric parameter 6th surface K = 0.0
A ₄ = −3.843970E-05
A ₆ = 1.211950E-07
A ₈ = −5.4666700E-09
A ₁₀ = 3.589930E-11
A ₁₂ = 5.576910E-13

7th surface K = 0.0
A ₄ = −6.222930E-05
A ₆ = 1.289240E-07
A ₈ = -9.269550E-09
A ₁₀ = 1.049680E-10
13th surface K = 0.0
A ₄ = 4.838910E-06
A ₆ = −2.840070E-07
A ₈ = 8.697220E-09
A ₁₀ = −1.836370E-11
14th surface K = 0.0
A ₄ = 4.698360E-05
A ₆ = −1.627670E-07
A ₈ = 5.742440E-09
A ₁₀ = 2.564070E-11

18th surface K = −1.373112
A ₄ = 1.668360E-05
A ₆ = 1.266830E-07
A ₈ = -5.146740E-09
A ₁₀ = _1.518190E-10
19th surface K = −2.895300E-02
A ₄ = 7.250660E-05
A ₆ = 6.967700E-07
A ₈ = −1.676340E−08
A ₁₀ = 2.591100E-10
In Example 4, the focal length f of the entire optical system, the variable distance DA between the first lens group G1 and the second lens group G2, and the variable distance between the second lens group G2 and the third lens group G3. The distance DB, the variable distance DC between the third lens group G3 and the aperture stop AD, the variable distance DD between the fourth lens group G4 and the fifth lens group G5, the fifth lens group G5 and the filter FG, etc. The variable intervals such as the variable interval DE are changed as shown in the following Table 8 along with zooming.

In the zoom lens of Example 4 described above, the values in the conditional expressions (1) to (7) described above are as shown in the column of Example 4 in Table 19 below.
In the zoom lens of Example 4 described above, the values of the parameters related to the conditional expressions (1) to (7) described above are all within the range of the conditional expressions.
FIGS. 14, 15 and 16 show aberration diagrams of spherical aberration, astigmatism, distortion and coma aberration at the wide-angle end, intermediate focal length and telephoto end, respectively, in Example 4. In each of these aberration diagrams, the broken line in the spherical aberration diagram represents the sine condition, the solid line in the astigmatism diagram represents the sagittal, and the broken line represents the meridional. In addition, “g” and “d” represent the g line and the d line, respectively.
In addition, at the wide angle end, distortion is corrected electronically so that the ideal image becomes 14.3 mm.

FIG. 17 schematically illustrates the lens configuration of the zoom lens optical system according to Example 5 according to the fifth embodiment of the present invention and the zoom locus associated with zooming from the wide-angle end to the telephoto end through a predetermined intermediate focal length. (A) is a cross-sectional view at a short focal end, that is, a wide-angle end, (b) is a cross-sectional view at a predetermined intermediate focal length, and (c) is a cross-sectional view at a long focal end, that is, a telephoto end. . In FIG. 17 showing the lens group arrangement of the fifth embodiment, the left side is the object (subject) side.
The zoom lens shown in FIG. 17 includes, in order from the object side along the optical axis, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a negative refractive power. A third lens group G3 having a positive refractive power, a fifth lens group G5 having a positive refractive power, and a third lens group G3 and a fourth lens group. An aperture stop AD is disposed between G4 and G4.
The first lens group G1 includes a first lens L1 and a second lens L2 sequentially from the object side. The second lens group G2 includes a third lens L3 and a fourth lens L4 sequentially from the object side. And the fifth lens L5, the third lens group G3 includes a single sixth lens L6, and the fourth lens group G4 sequentially includes, from the object side, the seventh lens L7, The eighth lens L8 and the ninth lens L9 are arranged, and the fifth lens group G5 is formed by sequentially arranging the tenth lens L10 and the eleventh lens L11 from the object side.

The first lens group G1 to the fifth lens group G5 are each supported by a common support frame or the like appropriate for each group, and operate integrally for each group during zooming or the like.
FIG. 17 also shows the surface numbers of the optical surfaces.
With the zooming from the wide-angle end (short focal end) to the telephoto end (long focal end), the entire first lens group G1 to fifth lens group G5 move to move the first lens group G1 and the second lens group G1. The distance between the lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases once and then increases, and the distance between the third lens group G3 and the fourth lens group G4 decreases. Then, the distance between the fourth lens group G4 and the fifth lens group G5 decreases. The aperture stop AD operates integrally with the fourth lens group G4.
The first lens group G1 includes, in order from the object side, a first lens L1 composed of a negative meniscus lens having a convex surface facing the object side, and a second lens L2 composed of a positive meniscus lens having a convex surface facing the object side. doing. The two lenses of the first lens L1 and the second lens L2 are closely bonded to each other and are integrally joined to form a cemented lens composed of two lenses.
The second lens group G2 is composed of a third lens L3 composed of a negative meniscus lens having a convex surface directed toward the object side in order from the object side, and a biconcave lens in which aspherical surfaces are formed on both surfaces with a stronger concave surface directed toward the image side. A fourth lens L4 and a fifth lens L5 composed of a biconvex lens having a stronger convex surface on the image side are arranged.

The third lens group G3 includes a single sixth lens L6 made of a negative meniscus lens having a strong concave surface facing the object side.
The aperture stop AD is interposed between the third lens group G3 and the fourth lens group G4 and operates integrally with the fourth lens group G4 as described above.
The fourth lens group G4 is composed of, from the object side, a seventh lens L7, which is a biconvex lens in which a strong convex surface is directed toward the object side and aspheric surfaces are formed on both surfaces, and a biconvex lens having a strong convex surface toward the image side. An eighth lens L8 and a ninth lens L9 made of a biconcave lens having a stronger concave surface on the image side are arranged. The two lenses of the eighth lens L8 and the ninth lens L9 are closely bonded to each other and joined together to form a cemented lens composed of two lenses.

The fifth lens group G5 is composed of a tenth lens L10, which is a biconvex lens in which an aspheric surface is formed on both sides of the object side, and a negative meniscus lens having a convex surface on the object side. An eleventh lens L11 is disposed.
In Example 5, the focal length f, F number F, and half angle of view ω of the entire optical system are f = 16.146 to 53.84, F = 3.63 to 5.74, and ω, respectively, by zooming. = 41.5 to 14.87. The optical characteristics of the optical elements in Example 5 are as shown in Table 9 below.

In Table 9, the lens surface with the surface number indicated by adding “*” to the surface number is an aspherical surface. The same applies to the other embodiments.
That is, in Table 9, the optical surfaces of the sixth surface, the seventh surface, the thirteenth surface, the fourteenth surface, the eighteenth surface, and the nineteenth surface marked with “*” are aspheric surfaces, and the formula [8 The parameters (aspheric coefficient) of each aspheric surface in] are as follows. In the aspheric parameter, “En” represents “power of 10”, that is, “× 10 ⁿ ”, for example, “E-5” represents “× 10 ⁻⁵ ”. The same applies to the other embodiments.
Aspherical parameter 6th surface K = 0
A ₄ = 5.52979E-05
A ₆ = −1.467723E-06
A ₈ = 1.40955E-08
A ₁₀ = −5.75258E-11

The seventh side K = 0
A ₄ = 3.02092E-05
A ₆ = −1.53901E−06
A ₈ = 1.44769E-08
A ₁₀ = −6.26901E-11
13th surface K = 0
A ₄ = −8.40542E-06
A ₆ = -4.37152E-07
A ₈ = 1.03740E-08
A ₁₀ = −2.45238E-10
14th surface K = 0
A ₄ = 2.47361E-05
A ₆ = −6.221729E-07
A ₈ = 1.37690E-08
A ₁₀ = −2.72842E−10

18th surface K = −0.92674
A ₄ = −1.83059E−05
A ₆ = -3.30349E-08
A ₈ = −2.28321E-09
A ₁₀ = −6.15846E-13
19th face K = 0
A ₄ = 3.19375E-05
A ₆ = 3.31577E-08
A ₈ = −2.88956E-09
A ₁₀ = 0
In Example 5, the focal length f of the entire optical system, the variable distance DA between the first lens group G1 and the second lens group G2, and the variable distance between the second lens group G2 and the third lens group G3. The distance DB, the variable distance DC between the third lens group G3 and the aperture stop AD, the variable distance DD between the fourth lens group G4 and the fifth lens group G5, the fifth lens group G5 and the filter FG, etc. The variable interval such as the variable interval DE is changed as shown in the following Table 10 with zooming.

In the zoom lens of Example 5 described above, the values in the conditional expressions (1) to (7) described above are as shown in the column of Example 5 in Table 19 below.
In the zoom lens of Example 5 described above, the values of the parameters related to the conditional expressions (1) to (7) described above are all within the range of the conditional expressions.
18, 19 and 20 show aberration diagrams of spherical aberration, astigmatism, distortion, and coma aberration at the wide-angle end, intermediate focal length, and telephoto end, respectively, in Example 5. In each of these aberration diagrams, the broken line in the spherical aberration diagram represents the sine condition, the solid line in the astigmatism diagram represents the sagittal, and the broken line represents the meridional. In addition, “g” and “d” represent the g line and the d line, respectively.

FIG. 21 schematically illustrates the lens configuration of the zoom lens optical system according to Example 6 of the sixth embodiment of the present invention and the zoom locus associated with zooming from the wide-angle end to the telephoto end through a predetermined intermediate focal length. (A) is a cross-sectional view at a short focal end, that is, a wide-angle end, (b) is a cross-sectional view at a predetermined intermediate focal length, and (c) is a cross-sectional view at a long focal end, that is, a telephoto end. . In FIG. 21 showing the arrangement of the lens groups in Example 6, the left side is the object (subject) side.
The zoom lens shown in FIG. 21 includes, in order from the object side along the optical axis, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a negative refractive power. A third lens group G3 having a positive refractive power, a fifth lens group G5 having a positive refractive power, and a third lens group G3 and a fourth lens group. An aperture stop AD is disposed between G4 and G4.
The first lens group G1 includes a first lens L1 and a second lens L2 sequentially from the object side. The second lens group G2 includes a third lens L3 and a fourth lens L4 sequentially from the object side. And the fifth lens L5, the third lens group G3 includes a single sixth lens L6, and the fourth lens group G4 sequentially includes, from the object side, the seventh lens L7, The eighth lens L8 and the ninth lens L9 are arranged, and the fifth lens group G5 is formed by sequentially arranging the tenth lens L10 and the eleventh lens L11 from the object side.

The first lens group G1 to the fifth lens group G5 are each supported by a common support frame or the like appropriate for each group, and operate integrally for each group during zooming or the like. With the zooming from the wide-angle end (short focal end) to the telephoto end (long focal end), the entire first lens group G1 to fifth lens group G5 move to move the first lens group G1 and the second lens group G1. The distance between the lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases once and then increases, and the distance between the third lens group G3 and the fourth lens group G4 decreases. Then, the distance between the fourth lens group G4 and the fifth lens group G5 decreases. The aperture stop AD operates integrally with the fourth lens group G4.
The first lens group G1 includes, in order from the object side, a first lens L1 composed of a negative meniscus lens having a convex surface facing the object side, and a second lens L2 composed of a positive meniscus lens having a convex surface facing the object side. doing. The two lenses of the first lens L1 and the second lens L2 are closely bonded to each other and are integrally joined to form a cemented lens composed of two lenses.
The second lens group G2 is composed of a third lens L3 composed of a negative meniscus lens having a convex surface directed toward the object side in order from the object side, and a biconcave lens in which aspherical surfaces are formed on both surfaces with a stronger concave surface directed toward the image side. A fourth lens L4 and a fifth lens L5 composed of a biconvex lens with a slightly strong convex surface facing the image side are arranged.

The third lens group G3 includes a single sixth lens L6 including a negative meniscus lens having a concave surface directed toward the object side.
The aperture stop AD is interposed between the third lens group G3 and the fourth lens group G4 and operates integrally with the fourth lens group G4 as described above.
The fourth lens group G4 includes, from the object side, a seventh lens L7 composed of a biconvex lens in which an aspheric surface is formed on both surfaces with a stronger convex surface directed toward the object side, and an eighth lens composed of a biconvex lens having the same curvature on both surfaces. L8 and a ninth lens L9 made of a biconcave lens having the same curvature on both sides are disposed. The two lenses of the eighth lens L8 and the ninth lens L9 are closely bonded to each other and joined together to form a cemented lens composed of two lenses.
The fifth lens group G5 is composed of a tenth lens L10, which is a biconvex lens in which an aspheric surface is formed on both sides of the object side, and a negative meniscus lens having a convex surface on the object side. An eleventh lens L11 is disposed.
In Example 6, the focal length f, the F number F, and the half angle of view ω of the entire optical system are f = 16.15 to 53.852, F = 3.62 to 5.77, and ω, respectively, by zooming. = 41.53 to 14.87. The optical characteristics of the optical elements in Example 6 are as shown in Table 11 below.

In Table 11, the lens surface with the surface number indicated by adding “*” to the surface number is an aspherical surface. The same applies to the other embodiments.
That is, in Table 11, the optical surfaces of the sixth surface, the seventh surface, the thirteenth surface, the fourteenth surface, the eighteenth surface, and the nineteenth surface marked with “*” are aspheric surfaces, and the formula [8 The parameters (aspheric coefficient) of each aspheric surface in] are as follows.
Aspherical parameter 6th surface K = 0
A ₄ = 2.63554E-05
A ₆ = −1.09237E-06
A ₈ = 9.8447E-09
A ₁₀ = −3.41409E-11

The seventh side K = 0
A ₄ = 2.93738E-06
A ₆ = −1.13624E-06
A ₈ = 1.01043E-08
A ₁₀ = −3.888306E-11
13th surface K = 0
A ₄ = 3.21402E-07
A ₆ = −1.03872E-07
A ₈ = 6.34622E-09
A ₁₀ = _-1.99948E-10
14th surface K = 0
A ₄ = 2.47699E-05
A ₆ = −2.4115E-07
A ₈ = 9.50458E-09
A ₁₀ = _-2.36136E-10

18th surface K = −0.57855
A ₄ = −1.83484E−05
A ₆ = −2.90044E−08
A ₈ = -1.90061E-09
A ₁₀ = −5.50054E-12
19th surface K = −0.09961
A ₄ = 3.54974E-05
A ₆ = 3.443435E-08
A ₈ = -3.14805E-09
In Example 6, the focal length f of the entire optical system, the variable distance DA between the first lens group G1 and the second lens group G2, and the variable distance between the second lens group G2 and the third lens group G3. The distance DB, the variable distance DC between the third lens group G3 and the aperture stop AD, the variable distance DD between the fourth lens group G4 and the fifth lens group G5, the fifth lens group G5 and the filter FG, etc. The variable interval such as the variable interval DE is changed as shown in the following Table 12 with zooming.

In the zoom lens of Example 6 described above, the values in the conditional expressions (1) to (7) described above are as shown in the column of Example 6 in Table 19 below.
In the zoom lens of Example 6 described above, the values of the parameters according to the conditional expressions (1) to (7) are all within the range of the conditional expressions.
FIGS. 22, 23, and 24 show spherical aberration, astigmatism, distortion, and coma aberration diagrams at the wide-angle end, the intermediate focal length, and the telephoto end, respectively, of Example 6. In each of these aberration diagrams, the broken line in the spherical aberration diagram represents the sine condition, the solid line in the astigmatism diagram represents the sagittal, and the broken line represents the meridional. In addition, “g” and “d” represent the g line and the d line, respectively.

FIG. 25 schematically illustrates the lens configuration of the optical system of the zoom lens of Example 7 according to the seventh embodiment of the present invention and the zoom locus associated with zooming from the wide-angle end to the telephoto end through a predetermined intermediate focal length. (A) is a cross-sectional view at a short focal end, that is, a wide-angle end, (b) is a cross-sectional view at a predetermined intermediate focal length, and (c) is a cross-sectional view at a long focal end, that is, a telephoto end. . In FIG. 25 showing the arrangement of lens groups in Example 7, the left side in the figure is the object (subject) side, and the right side is the image side.
The zoom lens shown in FIG. 25 includes, in order from the object side along the optical axis, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a negative refractive power. A third lens group G3 having a positive refractive power, a fifth lens group G5 having a positive refractive power, and a third lens group G3 and a fourth lens group. An aperture stop AD is disposed between G4 and G4.
The first lens group G1 includes a first lens L1 and a second lens L2 sequentially from the object side. The second lens group G2 includes a third lens L3 and a fourth lens L4 sequentially from the object side. And the fifth lens L5, the third lens group G3 includes a single sixth lens L6, and the fourth lens group G4 sequentially includes, from the object side, the seventh lens L7, The eighth lens L8 and the ninth lens L9 are arranged, and the fifth lens group G5 is formed by sequentially arranging the tenth lens L10 and the eleventh lens L11 from the object side.

The first lens group G1 to the fifth lens group G5 are each supported by a common support frame or the like appropriate for each group, and operate integrally for each group during zooming or the like.
FIG. 25 also shows the surface numbers of the optical surfaces.
With the zooming from the wide-angle end (short focal end) to the telephoto end (long focal end), the entire first lens group G1 to fifth lens group G5 move to move the first lens group G1 and the second lens group G1. The distance between the lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 increases, the distance between the third lens group G3 and the fourth lens group G4 decreases, and the fourth lens The distance between the group G4 and the fifth lens group G5 decreases. The aperture stop AD operates integrally with the fourth lens group G4.
The first lens group G1 includes, in order from the object side, a first lens L1 composed of a negative meniscus lens having a convex surface facing the object side, and a second lens L2 composed of a positive meniscus lens having a convex surface facing the object side. doing. The two lenses of the first lens L1 and the second lens L2 are closely bonded to each other and are integrally joined to form a cemented lens composed of two lenses.
The second lens group G2 is composed of a third lens L3 composed of a negative meniscus lens having a convex surface directed toward the object side in order from the object side, and a biconcave lens in which aspherical surfaces are formed on both surfaces with a stronger concave surface directed toward the image side. A fourth lens L4 and a fifth lens L5 made of a biconvex lens having the same curvature on both surfaces are disposed.

The third lens group G3 includes a single sixth lens L6 made of a negative meniscus lens having a strong concave surface facing the object side.
The aperture stop AD is interposed between the third lens group G3 and the fourth lens group G4 and operates integrally with the fourth lens group G4 as described above.
The fourth lens group G4 includes, from the object side, a seventh lens L7 composed of a biconvex lens in which an aspheric surface is formed on both surfaces with a stronger convex surface directed toward the object side, and an eighth lens composed of a biconvex lens having the same curvature on both surfaces. L8 and a ninth lens L9 made of a biconcave lens having the same curvature on both sides are disposed. The two lenses of the eighth lens L8 and the ninth lens L9 are closely bonded to each other and joined together to form a cemented lens composed of two lenses.
The fifth lens group G5 includes, from the object side, a tenth lens L10 including a biconvex lens in which a slightly strong convex surface is directed toward the object side and aspheric surfaces are formed on both surfaces, and a negative meniscus lens having a convex surface directed toward the object side 11th lens L11 which consists of.
In Example 7, the focal length f, the F number F, and the half angle of view ω of the entire optical system are f = 16.146 to 53.852, F = 3.61 to 5.76, and ω, respectively, by zooming. = 41.53 to 14.87. The optical characteristics of the optical elements in Example 7 are as shown in Table 13 below.

In Table 13, the lens surface with the surface number indicated by adding “*” to the surface number is an aspherical surface. The same applies to the other embodiments.
That is, in Table 13, the optical surfaces of the sixth surface, the seventh surface, the thirteenth surface, the fourteenth surface, the eighteenth surface, and the nineteenth surface marked with “*” are aspheric surfaces, and the equation [8 The parameters (aspheric coefficient) of each aspheric surface in] are as follows. In the aspheric parameter, “En” represents “power of 10”, that is, “× 10 ⁿ ”, for example, “E-05” represents “× 10 ⁻⁵ ”. The same applies to the other embodiments.
Aspherical parameter 6th surface K = 0
A ₄ = 3.46877E-05
A ₆ = −1.274443E-06
A ₈ = 1.11921E-08
A ₁₀ = −4.40045E-11

The seventh side K = 0
A ₄ = 6.8617E-06
A ₆ = −1.344447E-06
A ₈ = 1.13537E-08
A ₁₀ = −4.81564E-11
13th surface K = 0
A ₄ = −1.2513E-06
A ₆ = -4.84014E-08
A ₈ = 5.40686E-09
A ₁₀ = −2.0620E−10
14th surface K = 0
A ₄ = 2.71708E-05
A ₆ = −2.3373E-07
A ₈ = 9.93932E-09
A ₁₀ = −2.54318E−10

18th surface K = −0.65075
A ₄ = -1.90482E-05
A ₆ = -3.34777E-08
A ₈ = -1.71693E-09
A ₁₀ = −5.556274E-12
19th surface K = −0.20854
A ₄ = 3.63343E-05
A ₆ = 2.45318E-08
A ₈ = -2.95008E-09
In Example 7, the focal length f of the entire optical system, the variable distance DA between the first lens group G1 and the second lens group G2, and the variable distance between the second lens group G2 and the third lens group G3. The distance DB, the variable distance DC between the third lens group G3 and the aperture stop AD, the variable distance DD between the fourth lens group G4 and the fifth lens group G5, the fifth lens group G5 and the filter FG, etc. The variable interval such as the variable interval DE is changed as shown in the following Table 14 with zooming.

In the zoom lens of Example 7 described above, the values in the conditional expressions (1) to (7) described above are as shown in the column of Example 7 in Table 19 below.
In the zoom lens of Example 7 described above, the values of the parameters according to conditional expressions (1) to (7) are all within the range of the conditional expressions.
FIGS. 26, 27, and 28 show aberration diagrams of spherical aberration, astigmatism, distortion, and coma aberration at the wide-angle end, the intermediate focal length, and the telephoto end, respectively, according to the seventh embodiment. In each of these aberration diagrams, the broken line in the spherical aberration diagram represents the sine condition, the solid line in the astigmatism diagram represents the sagittal, and the broken line represents the meridional. In addition, “g” and “d” represent the g line and the d line, respectively. The same applies to the aberration diagrams of the other examples.

FIG. 29 schematically illustrates the lens configuration of the optical system of the zoom lens of Example 8 according to the eighth embodiment of the present invention and the zoom locus associated with zooming from the wide-angle end to the telephoto end through a predetermined intermediate focal length. (A) is a cross-sectional view at a short focal end, that is, a wide-angle end, (b) is a cross-sectional view at a predetermined intermediate focal length, and (c) is a cross-sectional view at a long focal end, that is, a telephoto end. . In FIG. 29 showing the lens group arrangement of Example 8, the left side in the figure is the object (subject) side, and the right side is the image side.
The zoom lens shown in FIG. 29 includes, in order from the object side along the optical axis, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a negative refractive power. A third lens group G3 having a positive refractive power, a fifth lens group G5 having a positive refractive power, and a third lens group G3 and a fourth lens group. An aperture stop AD is disposed between G4 and G4.
The first lens group G1 includes a first lens L1 and a second lens L2 sequentially from the object side. The second lens group G2 includes a third lens L3 and a fourth lens L4 sequentially from the object side. And the fifth lens L5, the third lens group G3 includes a single sixth lens L6, and the fourth lens group G4 sequentially includes, from the object side, the seventh lens L7, The eighth lens L8 and the ninth lens L9 are arranged, and the fifth lens group G5 is formed by sequentially arranging the tenth lens L10 and the eleventh lens L11 from the object side.

The first lens group G1 to the fifth lens group G5 are each supported by a common support frame or the like appropriate for each group, and operate integrally for each group during zooming or the like. FIG. 29 also shows the surface number of each optical surface. Note that each reference symbol in FIG. 1 is used independently for each embodiment in order to avoid complication of explanation due to an increase in the number of digits of the reference symbol. Therefore, a reference symbol common to the drawings according to the other embodiments. Even if attached, they are not necessarily a common configuration with other embodiments.
With the zooming from the wide-angle end (short focal end) to the telephoto end (long focal end), the entire first lens group G1 to fifth lens group G5 move to move the first lens group G1 and the second lens group G1. The distance between the lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 increases, the distance between the third lens group G3 and the fourth lens group G4 decreases, and the fourth lens The distance between the group G4 and the fifth lens group G5 decreases. The aperture stop AD operates integrally with the fourth lens group G4.
The first lens group G1 includes, in order from the object side, a first lens L1 composed of a negative meniscus lens having a convex surface facing the object side, and a second lens L2 composed of a positive meniscus lens having a convex surface facing the object side. doing. The two lenses of the first lens L1 and the second lens L2 are closely bonded to each other and are integrally joined to form a cemented lens composed of two lenses.

The second lens group G2 is composed of a third lens L3 composed of a negative meniscus lens having a convex surface directed toward the object side in order from the object side, and a biconcave lens in which aspherical surfaces are formed on both surfaces with a stronger concave surface directed toward the object side. A fourth lens L4 and a fifth lens L5 made of a biconvex lens having the same curvature on both surfaces are disposed.
The third lens group G3 includes a single sixth lens L6 made of a negative meniscus lens having a strong concave surface facing the object side.
The aperture stop AD is interposed between the third lens group G3 and the fourth lens group G4 and operates integrally with the fourth lens group G4 as described above.
The fourth lens group G4 includes, from the object side, a seventh lens L7 composed of a biconvex lens in which an aspheric surface is formed on both surfaces with a stronger convex surface directed toward the object side, and an eighth lens composed of a biconvex lens having the same curvature on both surfaces. L8 and a ninth lens L9 made of a biconcave lens having the same curvature on both sides are disposed. The two lenses of the eighth lens L8 and the ninth lens L9 are closely bonded to each other and joined together to form a cemented lens composed of two lenses.

The fifth lens group G5 includes, from the object side, a tenth lens L10 including a biconvex lens with a slightly strong convex surface facing the image side and aspheric surfaces on both surfaces, and a negative meniscus lens having a convex surface facing the object side 11th lens L11 which consists of.
In Example 8, the focal length f, F number F, and half angle of view ω of the entire optical system are f = 16.145 to 53.86, F = 3.64 to 5.75, and ω, respectively, by zooming. = 41.53 to 14.87. The optical characteristics of the optical elements in Example 8 are as shown in Table 15 below.

In Table 15, the lens surface with the surface number indicated by adding “* (asterisk)” to the surface number is an aspherical surface. The same applies to the other embodiments.
That is, in Table 15, the sixth, seventh, thirteenth, fourteenth, eighteenth, and nineteenth optical surfaces marked with “*” are aspheric surfaces, and the formula [8 The parameters (aspheric coefficient) of each aspheric surface in] are as follows. In the aspheric parameter, “En” represents “power of 10”, that is, “× 10 ⁿ ”, for example, “E-05” represents “× 10 ⁻⁵ ”. The same applies to the other embodiments.
Aspherical parameters 6th surface K = 0.000000E + 00
A ₄ = 2.855640E-05
A ₆ = −1.210950E-06
A ₈ = 1.113490E-08
A ₁₀ = −5.459440E-11

7th surface K = 0.00000000 + 00
A ₄ = 1.969800E-06
A ₆ = −1.114090E-06
A ₈ = 8.666190E-09
A ₁₀ = −3.9951870E-11
13th surface K = 0.00000000 + 00
A ₄ = −4.439230E-06
A ₆ = -9.177670E-08
A ₈ = 4.021770E-09
A ₁₀ = −1.681980E−10
14th surface K = 0.00000000 + 00
A ₄ = 2.834640E-05
A ₆ = −2.280050E-07
A ₈ = 6.993710E-09
A ₁₀ = _{-2.005280E-10}

18th surface K = −4.551530E-01
A ₄ = -2.952530E-05
A ₆ = 2.344050E-08
A ₈ = -4.179360E-09
A ₁₀ = 2.547520E-12
19th surface K = −6.6799000E-01
A ₄ = 2.331810E-05
A ₆ = 4.120810E-08 A ₈ = -4.205110E-09
In Example 8, the focal length f of the entire optical system, the variable distance DA between the first lens group G1 and the second lens group G2, and the variable distance between the second lens group G2 and the third lens group G3 are used. The distance DB, the variable distance DC between the third lens group G3 and the aperture stop AD, the variable distance DD between the fourth lens group G4 and the fifth lens group G5, the fifth lens group G5 and the filter FG, etc. The variable interval such as the variable interval DE is changed as shown in Table 16 along with zooming.

In the zoom lens of Example 8 described above, the values in the conditional expressions (1) to (7) described above are as shown in the column of Example 8 in Table 19 below.
In the zoom lens of Example 8 described above, the values of the parameters related to conditional expressions (1) to (7) are all within the range of the conditional expressions.
30, FIG. 31, and FIG. 32 show aberration diagrams of spherical aberration, astigmatism, distortion, and coma aberration at the wide-angle end, intermediate focal length, and telephoto end, respectively, of Example 8. In each of these aberration diagrams, the broken line in the spherical aberration diagram represents the sine condition, the solid line in the astigmatism diagram represents the sagittal, and the broken line represents the meridional. In addition, “g” and “d” represent the g line and the d line, respectively. The same applies to the aberration diagrams of the other examples.

FIG. 33 schematically shows the lens configuration of the optical system of the zoom lens of Example 9 according to the ninth embodiment of the present invention and the zoom locus accompanying zooming from the wide-angle end to the telephoto end through a predetermined intermediate focal length. (A) is a cross-sectional view at a short focal end, that is, a wide-angle end, (b) is a cross-sectional view at a predetermined intermediate focal length, and (c) is a cross-sectional view at a long focal end, that is, a telephoto end. . In FIG. 33 showing the lens group arrangement of Example 9, the left side in the figure is the object (subject) side, and the right side is the image side.
The zoom lens shown in FIG. 33 includes, in order from the object side along the optical axis, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a negative refractive power. A third lens group G3 having a positive refractive power, a fifth lens group G5 having a positive refractive power, and a third lens group G3 and a fourth lens group. An aperture stop AD is disposed between G4 and G4.
The first lens group G1 includes a first lens L1 and a second lens L2 sequentially from the object side. The second lens group G2 includes a third lens L3 and a fourth lens L4 sequentially from the object side. And the fifth lens L5, the third lens group G3 includes a single sixth lens L6, and the fourth lens group G4 sequentially includes, from the object side, the seventh lens L7, The eighth lens L8 and the ninth lens L9 are arranged, and the fifth lens group G5 is formed by sequentially arranging the tenth lens L10 and the eleventh lens L11 from the object side.

The first lens group G1 to the fifth lens group G5 are each supported by a common support frame or the like appropriate for each group, and operate integrally for each group during zooming or the like. FIG. 33 also shows the surface numbers of the optical surfaces. Note that each reference symbol in FIG. 33 is used independently for each embodiment in order to avoid complication of the explanation due to an increase in the number of digits of the reference symbol. However, they are not necessarily in common with other embodiments.
With the zooming from the wide-angle end (short focal end) to the telephoto end (long focal end), the entire first lens group G1 to fifth lens group G5 move to move the first lens group G1 and the second lens group G1. The distance between the lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 increases, the distance between the third lens group G3 and the fourth lens group G4 decreases, and the fourth lens The distance between the group G4 and the fifth lens group G5 decreases. The aperture stop AD operates integrally with the fourth lens group G4.
The first lens group G1 includes, in order from the object side, a first lens L1 composed of a negative meniscus lens having a convex surface facing the object side, and a second lens L2 composed of a positive meniscus lens having a convex surface facing the object side. doing. The two lenses of the first lens L1 and the second lens L2 are closely bonded to each other and are integrally joined to form a cemented lens composed of two lenses.

The second lens group G2 is composed of a third lens L3 composed of a negative meniscus lens having a convex surface directed toward the object side in order from the object side, and a biconcave lens in which aspherical surfaces are formed on both surfaces with a stronger concave surface directed toward the object side. A fourth lens L4 and a fifth lens L5 composed of a biconvex lens having a stronger convex surface on the image side are arranged.
The third lens group G3 includes a single sixth lens L6 made of a negative meniscus lens having a strong concave surface facing the object side.
The aperture stop AD is interposed between the third lens group G3 and the fourth lens group G4 and operates integrally with the fourth lens group G4 as described above.
The fourth lens group G4 is composed of, from the object side, a seventh lens L7, which is a biconvex lens in which a strong convex surface is directed toward the object side and aspheric surfaces are formed on both surfaces, and a biconvex lens having a strong convex surface toward the image side. An eighth lens L8 and a ninth lens L9 made of a biconcave lens having a stronger concave surface on the object side are arranged. The two lenses of the eighth lens L8 and the ninth lens L9 are closely bonded to each other and joined together to form a cemented lens composed of two lenses.
The fifth lens group G5 includes, from the object side, a tenth lens L10 including a biconvex lens in which a slightly strong convex surface is directed toward the object side and aspheric surfaces are formed on both surfaces, and a negative meniscus lens having a convex surface directed toward the object side 11th lens L11 which consists of.

  In Example 9, the focal length f, the F number F, and the half angle of view ω of the entire optical system are f = 16.19 to 45.75, F = 3.63 to 5.86, and ω, respectively, by zooming. = 41.45 to 17.36. The optical characteristics of the optical elements in Example 9 are as shown in Table 17 below.

In Table 17, the lens surface with the surface number indicated by adding “* (asterisk)” to the surface number is an aspherical surface. The same applies to the other embodiments.
That is, in Table 17, the optical surfaces of the sixth surface, the seventh surface, the thirteenth surface, the fourteenth surface, the eighteenth surface, and the nineteenth surface marked with “*” are aspheric surfaces, and the formula [8 The parameters (aspheric coefficient) of each aspheric surface in] are as follows. In the aspheric parameter, “En” represents “power of 10”, that is, “× 10 ⁿ ”, for example, “E-05” represents “× 10 ⁻⁵ ”. The same applies to the other embodiments.
Aspherical parameter 6th surface K = 0
A ₄ = −2.62797E-05
A ₆ = 2.15039E-07
A ₈ = 1.25881E-09
A ₁₀ = −3.373739E-11
A ₁₂ = -5.96466E-14

The seventh side K = 0
A ₄ = −6.94415E−05
A ₆ = 2.98647E-07
A ₈ = −1.81245E-09
A ₁₀ = −2.26671E-11
13th surface K = 0
A ₄ = -1.84404E-05
A ₆ = −9.86481E−08
A ₈ = 1.21421E-09
A ₁₀ = −2.38227E-11
14th surface K = 0
A ₄ = 9.50545E-06
A ₆ = 8.222895E-08
A ₈ = -9.41319E-10
A ₁₀ = −1.57178E-11
A ₁₂ = 0

18th surface K = -4.00213
A ₄ = 5.35275E-06
A ₆ = -6.14576E-08
A ₈ = -3.35757E-09
A ₁₀ = 3.63892E-11
19th surface K = −0.0203
A ₄ = 4.11207E-05
A ₆ = 6.45731E-08
A ₈ = -4.12993E-09
A ₁₀ = 4.1149E-11
In Example 9, the focal length f of the entire optical system, the variable distance DA between the first lens group G1 and the second lens group G2, and the variable distance between the second lens group G2 and the third lens group G3. The distance DB, the variable distance DC between the third lens group G3 and the aperture stop AD, the variable distance DD between the fourth lens group G4 and the fifth lens group G5, the fifth lens group G5 and the filter FG, etc. The variable interval such as the variable interval DE is changed as shown in the following Table 18 with zooming.
The glass material of the third lens group G3 is assumed to be S-PHM53 manufactured by OHARA.
Νd and θg, F of S-PHM53 are as follows from the published catalog.
νd = 65.44
θg, F = 0.5401 <−1.2 × 10 ⁻³ · 65.44 + 0.62 = 0.5415

In the zoom lens of Example 9 described above, the values in the conditional expressions (1) to (7) described above are as shown in the column of Example 9 in Table 19 below.
In the zoom lens of Example 9 described above, the values of the parameters related to conditional expressions (1) to (7) are all within the range of the conditional expressions.
Further, FIGS. 34, 35, and 36 show spherical aberration, astigmatism, distortion, and coma aberration diagrams at the wide-angle end, the intermediate focal length, and the telephoto end, respectively, of Example 9. In each of these aberration diagrams, the broken line in the spherical aberration diagram represents the sine condition, the solid line in the astigmatism diagram represents the sagittal, and the broken line represents the meridional. In addition, “g” and “d” represent the g line and the d line, respectively. The same applies to the aberration diagrams of the other examples.
In the zoom lenses of Examples 1 to 9, the values of the parameters related to the conditional expressions (1) to (7) described above are individually shown for each example.
The values of conditional expressions (1) to (7) in Examples 1 to 9 are collectively shown in the following table [19].

As shown in Table 19, in the zoom lenses of Examples 1 to 9, the values of the parameters according to the conditional expressions (1) to (7) described above are in the range of the respective conditional expressions.
Next, the present invention configured by adopting a zoom lens such as the first to ninth embodiments according to the first to ninth embodiments of the present invention as an imaging optical system. An information device according to the tenth embodiment will be described with reference to FIGS. FIG. 37 is a perspective view schematically showing an external configuration of a digital camera as an imaging apparatus according to the tenth embodiment of the present invention viewed from the object side, and FIG. 38 is a perspective view of the digital camera from the photographer side. It is a perspective view which shows typically the external appearance structure which looked. FIG. 39 is a block diagram showing a functional configuration of the digital camera. 37 to 39 illustrate a digital camera as an imaging device, but not only an imaging device mainly for imaging including a video camera and a conventional film camera using a so-called silver salt film. Mobile information terminals such as mobile phones and PDAs (personal data assistants), and various information devices including these functions, including mobile terminal devices such as so-called smartphones (registered trademark) and tablet terminals. In many cases, an imaging function corresponding to a digital camera or the like is incorporated. Although such an information device also has a slightly different appearance, it includes substantially the same functions and configuration as a digital camera or the like. Such an information device includes the above-described first to ninth embodiments of the present invention. The zoom lens according to the embodiment can be used as an imaging optical system.

As shown in FIGS. 37 and 38, the digital camera includes a camera body 105, an imaging lens 101, an optical viewfinder 102, a strobe (electronic flashlight) 103, a shutter button 104, a liquid crystal monitor 107, an operation button 108, and a memory card slot. 109, a zoom switch 110, and the like. Further, as shown in FIG. 39, the digital camera includes a central processing unit (CPU) 111, an image processing device 112, a light receiving element 113, a signal processing device 114, a semiconductor memory 115, a communication card 116 and the like in a camera body 105. It has.
The digital camera includes an imaging lens 101 as an imaging optical system, and a light receiving element 113 configured as an image sensor using a CMOS (complementary metal oxide semiconductor) imaging element or a CCD (charge coupled device) imaging element. The light receiving element 113 reads a subject optical image formed by the imaging lens 101. As the imaging lens 101, the zoom lens according to the first to ninth embodiments of the present invention as described in the first to ninth embodiments is used.
The output of the light receiving element 113 is processed by a signal processing device 114 controlled by the central processing unit 111 and converted into digital image information.

The image information digitized by the signal processing device 114 is recorded in a semiconductor memory 115 such as a nonvolatile memory after being subjected to predetermined image processing in the image processing device 112 which is also controlled by the central processing unit 111. In this case, the semiconductor memory 115 may be a memory card loaded in the memory card slot 109 or a semiconductor memory built on board in the digital camera body. The liquid crystal monitor 107 can display an image being photographed, or can display an image recorded in the semiconductor memory 115. Further, the image recorded in the semiconductor memory 115 is transmitted to the outside via a communication card 116 or the like loaded in a communication card slot (not explicitly shown, but may also be used as the memory card slot 109). Is also possible.
When the camera is carried, the objective surface of the imaging lens 101 is covered with a lens barrier (not shown). When the user operates the power switch 106 to turn on the power, the lens barrier opens and the objective surface The structure is exposed. At this time, in the lens barrel of the imaging lens 101, the optical systems of the respective groups constituting the zoom lens are, for example, arranged at the wide-angle end (short focal end), and by operating the zoom switch 110, When the arrangement of the group optical system is changed, the zooming operation to the telephoto end (long focal end) can be performed via the intermediate focal length. It is desirable that the optical system of the optical viewfinder 102 is also scaled in conjunction with the change in the angle of view of the imaging lens 101.

In many cases, focusing is performed by half-pressing the shutter button 104. Focusing in the zoom lenses according to the first to ninth embodiments of the present invention (the zoom lenses defined in claims 1 to 6 or shown in the first to ninth embodiments described above) is a zoom lens. Can be performed by moving a part of the plurality of groups of optical systems. When the shutter button 104 is further pushed down to the fully depressed state, photographing is performed, and then the processing as described above is performed.
When the image recorded in the semiconductor memory 115 is displayed on the liquid crystal monitor 107 or transmitted to the outside via the communication card 116 or the like, the operation button 108 is operated in a predetermined manner. The semiconductor memory 115 and the communication card 116 are used by being loaded into dedicated or general-purpose slots such as the memory card slot 109 and the communication card slot, respectively.
As described above, the image pickup apparatus such as the digital camera described above or an information apparatus having a similar image pickup function includes a zoom lens as in the first to ninth embodiments (Examples 1 to 9). The imaging lens 101 configured by using the imaging lens 101 can be used as an imaging optical system. Accordingly, it is possible to realize an information device such as a high-quality and small-sized digital camera using a light receiving element having a number of pixels exceeding 10 million pixels or a portable information terminal device having a similar imaging function. .
The configuration of the zoom lens according to the first to ninth embodiments of the present invention can also be applied as a photographing lens of a conventional silver salt film camera or a projection lens of a projector.

G1 first lens group (positive)
G2 Second lens group (negative)
G3 Third lens group (negative)
G4 4th lens group (positive)
G5 5th lens group (positive)
L1 to L11 Lens AD Aperture stop FG filter, etc. 101 Imaging lens 102 Optical viewfinder 103 Strobe (electronic flashlight)
104 Shutter button 105 Camera body 106 Power switch 107 Liquid crystal monitor 108 Operation button 109 Memory card slot 110 Zoom switch 111 Central processing unit (CPU)
112 Image processing device 113 Light receiving element (area sensor)
114 Signal processor 115 Semiconductor memory 116 Communication card, etc.

Japanese Patent Laid-Open No. 03-228008 Japanese Patent No. 3716418 Japanese Patent No. 3397686 Japanese Patent No. 4401451 JP 2010-175594 A

Claims (9)

A first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having negative refractive power in order from the object side to the image side along the optical axis A fourth lens group having a positive refracting power and a fifth lens group having a positive refracting power, an aperture stop between the third lens group and the fourth lens group, and a wide angle During zooming from the end to the telephoto end, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group increases, and the third lens group And a distance between the fourth lens group decreases, a distance between the fourth lens group and the fifth lens group changes, and the zoom lens performs focusing by the third lens group,
The average Abbe number of the second lens group is νd2g, the average Abbe number of the third lens group is νd3g, the average refractive index of d-line of the second lens group is nd2g, and the d-line of the third lens group The average refractive index of nd3g,
The following conditional expressions (1) and (2):
(1) 15 <νd3g−νd2g <35
(2) 0.15 <nd2g-nd3g <0.35
A zoom lens characterized by satisfying Assuming that the focal length of the third lens group is F3, the focal length at the wide angle end is Fw, the focal length at the telephoto end is Ft, and the intermediate focal length Fm is Fm = √ (Fw × Ft), Conditional expression (3) below:
(3) 1.0 <| F3 / Fm | <2.5
The zoom lens according to claim 1, wherein: When the average Abbe number of the second lens group is νd2g, the average Abbe number of the fourth lens group is νd4g, and the average Abbe number of the fifth lens group is νd5g, the following conditional expressions (4) and (5) :
(4) 10 <νd4g−νd2g <25
(5) 5 <νd5g−νd2g <20
The zoom lens according to claim 1, wherein the zoom lens satisfies the following.   The zoom lens according to any one of claims 1 to 3, wherein the third lens group includes one negative lens.   The zoom lens according to any one of claims 1 to 4, wherein all the lens groups move during zooming. When the focal length at the wide angle end is Fw, the focal length at the telephoto end is Ft, and the image height is Y ′, the following conditional expressions (6) and (7):
(6) 0.75 <Y ′ / Fw
(7) 2.8 <Ft / Fw
The zoom lens according to claim 1, wherein the zoom lens satisfies the following.   An information device having a photographing function, comprising the zoom lens according to claim 1 as a photographing optical system.   8. The information apparatus having a photographing function according to claim 7, wherein an object image formed by the zoom lens is formed on a light receiving surface of the image sensor.   A portable information terminal device comprising the zoom lens according to claim 1 as a photographing optical system of a photographing function unit.

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