JP7074985B2 - Imaging optical system - Google Patents

Description

The present invention is most suitable for digital cameras, silver salt cameras, video cameras, etc., and is particularly suitable for mirrorless cameras having an angle of view of about 46 ° to 65 ° and an F value of about F1.2 and a short back focus. Imaging optical system.

Generally, a large-diameter lens having a bright F-number of about F1.2 has a larger entrance pupil diameter than a lens having a darker F-number, so that it is difficult to correct spherical aberration and axial chromatic aberration. On the other hand, in recent digital cameras, the image sensor has a high pixel count, so especially in the case of an imaging optical system in which axial chromatic aberration is insufficiently corrected, the image may be colored on the image plane or blurred in the out-of-focus area. The coloring of the camera becomes remarkable. In order to solve such a problem, it is important to correct the axial chromatic aberration to be smaller.

The following patent documents disclose conventional imaging optical systems.

Patent Document 1 discloses an optical system having an angle of view of about 45 ° and an F value of about F1.2.

Further, Patent Document 2 discloses an optical system having an angle of view of about 49 ° and an F value of about F1.4.

Japanese Unexamined Patent Publication No. 2007-333790 Japanese Unexamined Patent Publication No. 2016-38418

However, the imaging optical system disclosed in Patent Document 1 is insufficient in axial chromatic aberration correction and has a long back focus, so that it is not the optimum imaging optical system for a mirrorless camera.

Further, the imaging optical system disclosed in Patent Document 2 has a short back focus and is the most suitable imaging optical system for a mirrorless camera. However, since the F value is about F1.4, it is difficult to correct spherical aberration and axial chromatic aberration with the disclosed imaging optical system when trying to brighten the F value to about F1.2.

Therefore, the present invention solves the problem of the conventional imaging optical system, shortens the back focus to suppress the total length of the optical system, satisfactorily corrects axial chromatic aberration, and has an F value of about F1.2. It is an object of the present invention to provide an optimum imaging optical system for a mirrorless camera.

－７．９６ ＜ ｆ１ｆ／ｆ ＜ －１．３３ （７）
但し、
Ｙは最大像高、
Ｂｆは前記第４レンズ群Ｌ４の最も像側の面の面頂から像面までの距離、
ＬＴは前記第１レンズ群Ｌ１の最も物体側の面の面頂から像面までの距離、
ｆはレンズ全系の無限遠合焦時の焦点距離、
ｆ１ｆは前記レンズ成分Ｌ１ｆの焦点距離であり、
Ａｃｉは以下の式で表される。
Ａｃｉ ＝ φｃｐｉ／νｄｃｐｉ ＋ φｃｍｉ／νｄｃｍｉ
但し、
φｃｐｉは、前記第１レンズ群Ｌ１に含まれる物体側からｉ番目の接合レンズの凸レンズ素子の屈折力、
νｄｃｐｉは、記第１レンズ群Ｌ１に含まれる物体側からｉ番目の接合レンズの凸レンズ素子のアッベ数、
φｃｍｉは、前記第１レンズ群Ｌ１に含まれる物体側からｉ番目の接合レンズの凹レンズ素子の屈折力、
νｄｃｍｉは、記第１レンズ群Ｌ１に含まれる物体側からｉ番目の接合レンズの凹レンズ素子のアッベ数である。
In order to solve the above problems, the imaging optical system of the present invention is sequentially arranged from the object side to the image side.
The first lens group L1 having a positive refractive power and
The second lens group L2 having a positive refractive power,
The third lens group L3 having a positive refractive power,
It consists of a fourth lens group L4 having a negative refractive power.
The first lens group L1 has at least one bonded lens, arranges a lens element having the most negative refractive power on the object side, and directs a convex surface toward the object side to have a positive refractive power. Arranged so as to be adjacent to the image side of the lens element having the refractive power of
At the time of focusing, the second lens group L2 and the third lens group L3 move toward the object side by different amounts of movement, and the first lens group L1 and the fourth lens group L4 move with respect to the image plane. The lens component L1f is from the most object-side surface of the first lens group L1 to the image-side surface of the lens element having a negative refractive power with the convex surface facing the object side, and the lens component L1f is negative. It is characterized by having the refractive power of the above and satisfying the following conditional expression.
Y / Bf> 0.80 (1)
LT / f <4.20 (2)

-7.96 <f1f / f <-1.33 (7)
however,
Y is the maximum image height,
Bf is the distance from the top of the surface on the image side of the fourth lens group L4 to the image surface.
LT is the distance from the top of the surface of the first lens group L1 on the most object side to the image plane.
f is the focal length of the entire lens system at infinity focusing ,
f1f is the focal length of the lens component L1f .
Aci is expressed by the following equation.
Aci = φcpi / νdcpi + φcmi / νdcmi
however,
φcpi is the refractive power of the convex lens element of the i-th junction lens from the object side included in the first lens group L1.
νdcpi is the Abbe number of the convex lens element of the i-th junction lens from the object side included in the first lens group L1.
φcmi is the refractive power of the concave lens element of the i-th junction lens from the object side included in the first lens group L1.
νdcmi is the Abbe number of the concave lens element of the i-th junction lens from the object side included in the first lens group L1.

Further, the second invention is further characterized in that, in the first invention, the lens element L1p having a positive refractive power arranged on the most image side of the first lens group L1 satisfies the following conditional expression. It is an imaging optical system.
νdL1p <30 (4)
0.0090 <ΔPgfL1p (5)
however,
ΔPgfL1p is the anomalous dispersibility of the positive lens element L1p and is expressed by the following equation.
ΔPgfL1p = PgfL1p + 0.0018 × νdL1p ― 0.64833
however,
νdL1p is the Abbe number νd of the positive lens element L1p.
PgfL1p is a partial dispersion ratio Pgf with respect to the g-line and the F-line of the positive lens element L1p.

Further, the third invention is an imaging optical system characterized in that the following conditional expressions are further satisfied in the first and second inventions.
0.88 <Fno ・ (f3 / f) <1.96 (6)
however,
Fno is the F value of the entire lens system when focusing at infinity,
f3 is the focal length of the third lens group L3,
f is the focal length of the entire lens system at infinity focusing.

Further, the fourth invention is an imaging optical system characterized in that the following conditional expressions are further satisfied in the first to third inventions.
β1b <0.50 (8)
however,
β1b is the lateral magnification of the lens system arranged on the image side of the first lens group L1 at the time of infinity focusing.

According to the present invention, spherical aberration and axial chromatic aberration, which have been problems of conventional imaging optical systems, are satisfactorily corrected, and optimum imaging is performed for a mirrorless camera having a short back focus and an F value of about F1.2. An optical system can be provided.

It is a lens block diagram at the time of infinity focusing which concerns on Example 1 of this invention. It is a longitudinal aberration diagram at the time of infinity focusing which concerns on Example 1 of this invention. FIG. 3 is a longitudinal aberration diagram at a shooting distance of 2157 mm according to the first embodiment of the present invention. It is a lateral aberration diagram at the time of infinity focusing which concerns on Example 1 of this invention. FIG. 3 is a lateral aberration diagram at a shooting distance of 2157 mm according to the first embodiment of the present invention. It is a lens block diagram at the time of infinity focusing which concerns on Example 2 of this invention. It is a longitudinal aberration diagram at the time of infinity focusing which concerns on Example 2 of this invention. FIG. 3 is a longitudinal aberration diagram at a shooting distance of 2158 mm according to the second embodiment of the present invention. It is a lateral aberration diagram at the time of infinity focusing which concerns on Example 2 of this invention. FIG. 3 is a lateral aberration diagram at a shooting distance of 2158 mm according to the second embodiment of the present invention. It is a lens block diagram at the time of infinity focusing which concerns on Example 3 of this invention. It is a longitudinal aberration diagram at the time of infinity focusing which concerns on Example 3 of this invention. It is a longitudinal aberration diagram at a shooting distance of 2166 mm according to the third embodiment of the present invention. It is a lateral aberration diagram at the time of infinity focusing which concerns on Example 3 of this invention. FIG. 3 is a lateral aberration diagram at a shooting distance of 2166 mm according to the third embodiment of the present invention. It is a lens block diagram at the time of infinity focusing which concerns on Example 4 of this invention. It is a longitudinal aberration diagram at the time of infinity focusing which concerns on Example 4 of this invention. FIG. 3 is a longitudinal aberration diagram at a shooting distance of 1764 mm according to the fourth embodiment of the present invention. It is a lateral aberration diagram at the time of infinity focusing which concerns on Example 4 of this invention. FIG. 3 is a lateral aberration diagram at a shooting distance of 1764 mm according to the fourth embodiment of the present invention. It is a lens block diagram at the time of infinity focusing which concerns on Example 5 of this invention. It is a longitudinal aberration diagram at the time of infinity focusing which concerns on Example 5 of this invention. It is a longitudinal aberration diagram at a shooting distance of 1828 mm according to the fifth embodiment of the present invention. It is a lateral aberration diagram at the time of infinity focusing which concerns on Example 5 of this invention. FIG. 5 is a lateral aberration diagram at a shooting distance of 1828 mm according to the fifth embodiment of the present invention. It is a lens block diagram at the time of infinity focusing which concerns on Example 6 of this invention. It is a longitudinal aberration diagram at the time of infinity focusing which concerns on Example 6 of this invention. It is a longitudinal aberration diagram at a shooting distance of 1709 mm according to the sixth embodiment of the present invention. It is a lateral aberration diagram at the time of infinity focusing which concerns on Example 6 of this invention. It is a lateral aberration diagram at a photographing distance 1709 mm which concerns on Example 6 of this invention. It is a lens block diagram at the time of infinity focusing which concerns on Example 7 of this invention. It is a longitudinal aberration diagram at the time of infinity focusing which concerns on Example 7 of this invention. FIG. 3 is a longitudinal aberration diagram at a shooting distance of 1646 mm according to the seventh embodiment of the present invention. It is a lateral aberration diagram at the time of infinity focusing which concerns on Example 7 of this invention. FIG. 3 is a lateral aberration diagram at a shooting distance of 1646 mm according to the seventh embodiment of the present invention. It is a lens block diagram at the time of infinity focusing which concerns on Example 8 of this invention. It is a longitudinal aberration diagram at the time of infinity focusing which concerns on Example 8 of this invention. It is a longitudinal aberration diagram at a photographing distance of 1565 mm which concerns on Example 8 of this invention. It is a lateral aberration diagram at the time of infinity focusing which concerns on Example 8 of this invention. It is a lateral aberration diagram at a photographing distance of 1565 mm which concerns on Example 8 of this invention.

Hereinafter, examples of the optical system according to the present invention will be described in detail. It should be noted that the following description of the examples describes an example of the optical system of the present invention, and the present invention is not limited to the present embodiment as long as the gist of the present invention is not deviated.

但し、
Ｙは最大像高、
Ｂｆは前記第４レンズ群Ｌ４の最も像側の面の面頂から像面までの距離、
ＬＴは前記第１レンズ群Ｌ１の最も物体側の面の面頂から像面までの距離、
ｆはレンズ全系の無限遠合焦時の焦点距離であり、
Ａｃｉは以下の式で表される。
Ａｃｉ ＝ φｃｐｉ／νｄｃｐｉ ＋ φｃｍｉ／νｄｃｍｉ
但し、
φｃｐｉは、前記第１レンズ群Ｌ１に含まれる物体側からｉ番目の接合レンズの凸レンズ素子の屈折力、
νｄｃｐｉは、記第１レンズ群Ｌ１に含まれる物体側からｉ番目の接合レンズの凸レンズ
素子のアッベ数、
φｃｍｉは、前記第１レンズ群Ｌ１に含まれる物体側からｉ番目の接合レンズの凹レンズ素子の屈折力、
νｄｃｍｉは、記第１レンズ群Ｌ１に含まれる物体側からｉ番目の接合レンズの凹レンズ素子のアッベ数である。 The imaging optical system of this embodiment is in order from the object side to the image side.
The first lens group L1 having a positive refractive power and
The second lens group L2 having a positive refractive power,
The third lens group L3 having a positive refractive power,
It consists of a fourth lens group L4 having a negative refractive power.
The first lens group L1 has at least one bonded lens, arranges a lens element having the most negative refractive power on the object side, and directs a convex surface toward the object side to have a positive refractive power. Arranged so as to be adjacent to the image side of the lens element having the refractive power of
At the time of focusing, the second lens group L2 and the third lens group L3 move toward the object side by different amounts of movement, and the first lens group L1 and the fourth lens group L4 move with respect to the image plane. It is fixed and is characterized by satisfying the following conditional expression.
Y / Bf> 0.80 (1)
LT / f <4.20 (2)

however,
Y is the maximum image height,
Bf is the distance from the top of the surface on the image side of the fourth lens group L4 to the image surface.
LT is the distance from the top of the surface of the first lens group L1 on the most object side to the image plane.
f is the focal length of the entire lens system at infinity focusing.
Aci is expressed by the following equation.
Aci = φcpi / νdcpi + φcmi / νdcmi
however,
φcpi is the refractive power of the convex lens element of the i-th junction lens from the object side included in the first lens group L1.
νdcpi is the Abbe number of the convex lens element of the i-th junction lens from the object side included in the first lens group L1.
φcmi is the refractive power of the concave lens element of the i-th junction lens from the object side included in the first lens group L1.
νdcmi is the Abbe number of the concave lens element of the i-th junction lens from the object side included in the first lens group L1.

When the refractive indexes of the F line, d line, and C line are NF, Nd, and NC, respectively, the Abbe number νd is expressed by the following equation.
νd = (Nd-1) / (NF-NC)

A lens element having a negative refractive power is arranged on the most object side of the first lens group L1, and a lens element having a positive refractive power with a convex surface facing the object side is an image side of the lens element having a negative refractive power. By arranging the lens adjacent to the lens, it is possible to effectively correct the curvature of field and the coma of the entire lens system. Furthermore, by arranging at least one junction lens in the first lens group L1, it is possible to effectively correct the axial chromatic aberration of the entire lens system.

When focusing, the second lens group L2 and the third lens group L3 move toward the object with different movement amounts, so that it is possible to suppress fluctuations in spherical aberration especially during focusing.

The conditional expression (1) defines the back focus of the entire lens system for miniaturization.

If the lower limit of the conditional expression (1) is exceeded and the back focus of the entire lens system becomes long, the total length of the entire lens system becomes long, which is disadvantageous for miniaturization and unsuitable for a mirrorless camera.

By defining the lower limit value of 0.82 for the above-mentioned conditional expression (1), the above-mentioned effect can be further ensured.

The conditional expression (2) defines the total length of the entire lens system in order to avoid excessive enlargement of the optical system.

If the upper limit of the conditional expression (2) is exceeded, the total length of the entire lens system increases, which leads to an excessive increase in size and weight of the product.

By defining the upper limit value of 3.90 for the above-mentioned conditional expression (2), the above-mentioned effect can be further ensured.

The conditional expression (3) defines the sum of the primary achromatic conditions of the bonded lens included in the first lens group L1 in order to improve the performance.

If the upper limit of the conditional expression (3) is exceeded and the sum of the achromatic conditions of the bonded lens included in the first lens group L1 becomes large, the primary achromatic effect becomes insufficient and the axial chromatic aberration worsens. It ends up.

By limiting the upper limit of the conditional expression (3) to 0.0020, the above-mentioned effect can be further ensured.

Further, the lens element L1p having a positive refractive power arranged on the most image side of the first lens group L1 is characterized by satisfying the following conditional expression.
νdL1p <30 (4)
0.0090 <ΔPgfL1p (5)
however,
ΔPgfL1p is the anomalous dispersibility of the positive lens element L1p and is expressed by the following equation.
ΔPgfL1p = PgfL1p + 0.0018 × νdL1p ― 0.64833
however,
νdL1p is the Abbe number νd of the positive lens element L1p.
PgfL1p is a partial dispersion ratio Pgf with respect to the g-line and the F-line of the positive lens element L1p.

The conditional expressions (4) and (5) define the Abbe number νd and the anomalous dispersibility ΔPgf of the positive lens element L1p in order to improve the performance.

When the refractive indexes of the g-line, F-line, d-line, and C-line are Ng, NF, Nd, and NC, respectively, the partial dispersion ratio Pgf is expressed by the following equation.
Pgf = (Ng-NF) / (NF-NC)

When the upper limit of the conditional expression (4) is exceeded and the lower limit of the conditional expression (5) is exceeded, the Abbe number νd of the positive lens element L1p becomes large and the anomalous dispersibility ΔPgf becomes small, the correction of the secondary spectrum is particularly corrected. Due to the shortage, the axial chromatic aberration worsens.

By limiting the upper limit value of the conditional expression (4) to 27 and the lower limit value of the conditional expression (5) to 0.0100, the above-mentioned effect can be further ensured.

Further, it is characterized by satisfying the following conditional expression.
0.88 <Fno ・ (f3 / f) <1.96 (6)
however,
Fno is the F value of the entire lens system when focusing at infinity,
f3 is the focal length of the third lens group L3,
f is the focal length of the entire lens system at infinity focusing.

Conditional expression (6) defines the refractive power of the third lens group L3 and the F value of the entire lens system at infinity in focus in order to reduce the size and alleviate the performance deterioration due to manufacturing errors.

When the upper limit of the conditional expression (6) is exceeded and the F value of the entire lens system at infinity becomes dark, or the refractive power of the third lens group L3 becomes weak, the apparent F in the third lens group L3 Since the value becomes dark, it is advantageous for mitigating performance deterioration when the third lens group L3 is eccentric due to a manufacturing error, but since the amount of movement during focusing increases, the total length of the lens becomes long and it is suitable for miniaturization. It will be disadvantageous.

If the lower limit of the conditional expression (6) is exceeded, the refractive power of the third lens group L3 becomes stronger, or the F value of the entire lens system at infinity focusing becomes brighter, the amount of movement during focusing decreases. Although it is advantageous for miniaturization, since the apparent F value in the third lens group L3 becomes brighter, the axial light beam in the third lens group L3 increases, and only the diameter of the third lens group L3 increases. This leads to an increase in spherical aberration, which makes it difficult to correct it satisfactorily. Further, when the third lens group L3 is eccentric due to a manufacturing error, the center performance may be significantly deteriorated.

By limiting the lower limit value of the conditional expression (6) to 1.00 and the upper limit value to 1.76, the above-mentioned effect can be further ensured.

Further, the lens component L1f is from the surface on the most object side of the first lens group L1 to the surface on the image side of the lens element having a convex surface facing the object side and having a negative refractive power, and the lens component L1f has a negative refractive power. It is characterized by having and satisfying the following conditional expression.
-7.96 <f1f / f <-1.33 (7)
however,
f1f is the focal length of the lens component L1f,
f is the focal length of the entire lens system at infinity focusing.

The conditional expression (7) defines the refractive power of the lens component L1f for miniaturization.

When the upper limit of the conditional expression (7) is exceeded and the refractive power of the lens component L1f becomes stronger, the divergent action of the lens component L1f becomes stronger. Since the height of the light beam in the lens component increases and the lens diameter increases, the product diameter increases.

When the lower limit of the conditional equation (7) is exceeded and the refractive power of the lens component L1f is weakened, the divergent action of the lens component is weakened. Although the ray height in the component does not increase, the ray height in the lens component L1f itself increases and the lens diameter increases, which leads to an increase in the product diameter.

By limiting the upper limit value of the conditional expression (7) to −1.60 and the lower limit value to −6.70, the above-mentioned effect can be further ensured.

Further, it is characterized by satisfying the following conditional expression.
β1b <0.50 (8)
however,
β1b is the lateral magnification of the lens system arranged on the image side of the first lens group L1 at the time of infinity focusing.

The conditional expression (8) defines the lateral magnification of the lens system arranged on the image side of the first lens group L1 in order to improve the performance.

If the upper limit of the conditional expression (8) is exceeded and the lateral magnification of the lens system arranged on the image side of the first lens group L1 becomes larger, the aberration generated in the first lens group L1 is enlarged, so that the performance is improved. Is at a disadvantage.

By limiting the upper limit of the conditional expression (8) to 0.43, the above-mentioned effect can be further ensured.

Further, it is preferable that the most image-side surface of the fourth lens group L4 has a concave surface facing the image side. As a result, the concave surface becomes a field flattener, and the curvature of field is corrected more effectively.

Hereinafter, numerical data of Examples 1 to 8 of the imaging optical system according to the present invention are shown.

In [plane data], the surface number is the number of the lens surface or aperture stop counted from the object side, r is the refractive index of each surface, d is the distance between the surfaces, and nd is the d line (wavelength λ = 587.56 nm). The refractive index and νd indicate the Abbe number with respect to the d line. In addition, BF represents back focus.

The radius of curvature ∞ (infinity) with respect to a flat surface or an aperture stop is entered in the area numbered (aperture).

In [Aspherical surface data], each coefficient value that gives the aspherical surface shape of the lens surface marked with * in [Surface data] is shown. The shape of the aspherical surface is y for the displacement in the direction orthogonal to the optical axis, z for the displacement (sag amount) in the optical axis direction from the intersection of the aspherical surface and the optical axis, and K, 4, 6, 8 for the conic coefficient. When the 10th and 12th order aspherical coefficients are set as A4, A6, A8, A10, and A12, respectively, the coordinates of the aspherical surface are expressed by the following equations.

[Various data] shows values such as focal length.

[Variable interval data] shows the values of the variable interval and the BF (back focus).

[Lens group data] shows the surface number on the most object side constituting each lens group and the combined focal length of the entire group. In all the following specification values, the focal length f, the radius of curvature r, the lens surface spacing d, and other length units are described in millimeters (mm) unless otherwise specified, but optics. The system is not limited to this because the same optical performance can be obtained in both proportional expansion and proportional reduction.

Further, in the aberration diagram corresponding to each embodiment, d, g, and C represent the d-line, g-line, and C-line, respectively, and ΔS and ΔM represent the sagittal image plane and the meridional image plane, respectively. Further, in the lens configuration diagram shown in FIGS. 1, 6, 11, 16, 21, 26, 31, and 36, S is an aperture diaphragm, I is an image plane, LPF is a low-pass filter, and the alternate long and short dash line passing through the center is an optical axis.

The specification values of the imaging optical system according to each embodiment are shown below. In [plane data], the first column is the order of the lens surfaces counted from the object side, the r in the second column is the radius of curvature of the lens surface, the third column d is the lens surface spacing, and the fourth column nd is the d line (wavelength). The refractive index at λ = 587.56 nm) and the fifth column νd represent the Abbe number at the d line (wavelength λ = 587.56 nm). Further, r = ∞ represents a plane, (BF) indicates a back focus, (aperture) indicates a diaphragm surface, and the refractive index n = 1.0000 of air is omitted.

FIG. 1 is a lens configuration diagram of the imaging optical system according to the first embodiment at infinity focusing. The imaging optical system of the first embodiment has a first lens group L1 having a fixed positive refractive power during focusing and a second lens group L1 moving to the object side during focusing and having a positive refractive power in order from the object side to the image side. The lens group L2, the third lens group L3 that moves toward the object with a different amount of movement from the second lens group L2 during focusing and has a positive refractive power, and the fourth lens group L4 that has a fixed negative refractive power during focusing. It is composed of and.

The first lens group L1 is composed of a concave meniscus lens having a convex surface facing the object side, a convex meniscus lens having a convex surface facing the object side, and a concave meniscus lens having a convex surface facing the object side in order from the object side to the image side. It is composed of a lens component L1f to be formed, a convex meniscus lens having a convex surface facing the object side, a junction lens of a biconcave lens and a biconvex lens, and a junction lens of a biconcave lens and a biconvex lens element L1p.

The second lens group L2 is composed of a biconvex lens having both R1 and R2 surfaces aspherical surfaces, and a junction lens of a biconvex lens and a biconcave lens in order from the object side to the image side.

The third lens group L3 includes a junction lens of a biconcave lens and a biconvex lens, a biconvex lens, and a convex meniscus lens in which both R1 and R2 surfaces are aspherical and the concave surface faces the object side, in order from the object side to the image side. Consists of.

The fourth lens group L4 is composed of a junction lens of a biconvex lens and a biconcave lens in order from the object side to the image side.

The aperture stop S is arranged between the second lens group L2 and the third lens group L3, and moves together with the third lens group L3 during focusing.

Subsequently, the specification values of the imaging optical system according to the first embodiment are shown below.

Numerical Example 1
Unit: mm
[Surface data]
Face number rd nd vd
Paraboloid ∞ (d0)
1 174.3636 2.0000 1.51742 52.15
2 46.9132 0.1500
3 44.4646 11.8091 2.00069 25.46
4 175.7292 0.5000
5 138.0277 1.5000 1.74000 28.30
6 33.9507 4.1164
7 44.4897 3.7606 1.83400 37.34
8 60.1885 7.5271
9 -103.3975 1.0000 1.85478 24.80
10 28.1754 18.0826 1.77250 49.62
11 -90.8319 2.7978
12 -53.5734 1.0000 1.58144 40.75
13 43.2889 9.7880 2.00069 25.46
14 -206.7454 d14
15 * 49.6476 8.0731 1.82080 42.71
16 * -188.0627 0.1500
17 349.8022 7.3194 1.49700 81.61
18 -40.7815 1.1755 1.67270 32.17
19 69.2391 d19
(Aperture) ∞ 14.5446
21 -25.2369 1.0000 1.69895 30.05
22 209.8459 3.1699 1.49700 81.61
23 -209.8459 0.2000
24 97.9223 6.7758 1.77250 49.62
25 -39.6611 0.2000
26 * -535.7926 2.8646 1.80610 40.73
27 * -68.4332 d27
28 62.3410 6.7964 2.00069 25.46
29 -84.5557 1.5000 1.80518 25.46
30 36.3089 17.9286
31 ∞ 2.5000 1.51680 64.20
32 ∞ BF
Image plane ∞

[Aspherical data]
15 sides 16 sides 26 sides 27 sides
K 0.0000E + 00 0.0000E + 00 0.0000E + 00 0.0000E + 00
A4 7.7557E-07 1.7836E-06 -3.8902E-06 2.4706E-06
A6 1.0202E-09 -5.0062E-10 -1.5772E-08 -1.4034E-08
A8 4.3706E-13 7.2595E-14 6.1317E-11 5.9831E-11
A10 1.2959E-16 -1.3700E-15 -6.3933E-14 -5.7108E-14
A12 0.0000E + 00 0.0000E + 00 0.0000E + 00 0.0000E + 00

[Various data]
INF
Focal length 50.99
F number 1.25
Full angle of view 2ω 45.97
Image height Y 21.63
Lens total length 154.20

[Variable interval data]
INF Shooting distance 2157mm
d0 ∞ 2002.4093
d14 10.1569 8.6926
d19 3.3130 3.5348
d27 1.5000 2.7425
BF 1.0000 1.0000

[Lens group data]
Focal length of group origin
L1 1 534.25
L2 15 94.67
L3 20 60.43
L4 28 -417.98
L1f 1 -184.54

FIG. 6 is a lens configuration diagram of the imaging optical system according to the second embodiment at infinity focusing. In the imaging optical system of the second embodiment, the first lens group L1 having a fixed positive refractive power at the time of focusing and the second lens group L1 moving to the object side at the time of focusing and having a positive refractive power in order from the object side to the image side. The lens group L2, the third lens group L3 that moves toward the object with a different amount of movement from the second lens group L2 during focusing and has a positive refractive power, and the fourth lens group L4 that has a fixed negative refractive power during focusing. It is composed of and.

The first lens group L1 is a junction lens of a concave meniscus lens having a convex surface facing the object side, a convex meniscus lens having a convex surface facing the object side, and a concave meniscus lens having a convex surface facing the object side in order from the object side to the image side. It is composed of a lens component L1f composed of the above, a convex meniscus lens having a convex surface facing the object side, a junction lens of a biconcave lens and a biconvex lens, and a junction lens of a biconcave lens and a biconvex lens element L1p.

The second lens group L2 is composed of a biconvex lens having both R1 and R2 surfaces aspherical surfaces, and a junction lens of a biconvex lens and a biconcave lens in order from the object side to the image side.

The third lens group L3 includes a junction lens of a biconcave lens and a biconvex lens, a biconvex lens, and a convex meniscus lens in which both R1 and R2 surfaces are aspherical and the concave surface faces the object side, in order from the object side to the image side. Consists of.

The fourth lens group L4 is composed of a junction lens of a biconvex lens and a biconcave lens in order from the object side to the image side.

The aperture stop S is arranged between the second lens group L2 and the third lens group L3, and moves together with the third lens group L3 during focusing.

Subsequently, the specification values of the imaging optical system according to the second embodiment are shown below.

Numerical Example 2
Unit: mm
[Surface data]
Face number rd nd vd
Paraboloid ∞ (d0)
1 161.2931 2.0000 1.54814 45.82
2 43.1964 12.0749 2.00069 25.46
3 175.9647 0.5000
4 138.2379 1.5000 1.74000 28.30
5 35.3803 4.4285
6 49.5436 3.5339 1.83400 37.34
7 68.0014 7.0556
8-105.1012 1.0000 1.85478 24.80
9 28.1754 18.3687 1.77250 49.62
10 -93.8678 2.7725
11 -53.7480 1.0000 1.58144 40.75
12 44.0390 9.9013 2.00069 25.46
13 -177.8893 d13
14 * 51.1697 7.9932 1.82080 42.71
15 * -189.8824 0.1500
16 363.0987 7.5626 1.49700 81.61
17 -39.3800 2.0284 1.67270 32.17
18 70.3322 d18
(Aperture) ∞ 14.4485
20 -24.6947 1.0000 1.69895 30.05
21 187.4269 3.2412 1.49700 81.61
22 -187.4269 0.2000
23 106.5129 6.3642 1.77250 49.62
24-38.5019 0.2000
25 * -471.9072 2.8399 1.80610 40.73
26 * -67.1044 d26
27 62.6445 6.5203 2.00069 25.46
28 -83.9662 1.5000 1.80518 25.46
29 37.1867 18.4276
30 ∞ 2.5000 1.51680 64.20
31 ∞ BF
Image plane ∞

[Aspherical data]
14 faces 15 faces 25 faces 26 faces
K 0.0000E + 00 0.0000E + 00 0.0000E + 00 0.0000E + 00
A4 9.1564E-07 1.7187E-06 -4.0582E-06 2.0938E-06
A6 6.7897E-10 -1.1387E-09 -1.4473E-08 -1.2608E-08
A8 9.2643E-13 1.8851E-12 6.2810E-11 6.0135E-11
A10 5.0392E-16 -2.6450E-15 -7.0590E-14 -6.1286E-14
A12 0.0000E + 00 0.0000E + 00 0.0000E + 00 0.0000E + 00

[Various data]
INF
Focal length 50.99
F number 1.25
Full angle of view 2ω 45.92
Image height Y 21.63
Lens total length 155.04

[Variable interval data]
INF Shooting distance 2158mm
d0 ∞ 2003.1325
d13 10.4606 8.9601
d18 2.9663 3.2231
d26 1.5000 2.7437
BF 1.0000 1.0000

[Lens group data]
Focal length of group origin
L1 1 440.01
L2 14 99.53
L3 19 61.40
L4 27 -495.88
L1f 1 -190.74

FIG. 11 is a lens configuration diagram of the imaging optical system according to the third embodiment at infinity focusing. In the imaging optical system of the third embodiment, the first lens group L1 having a fixed positive refractive power at the time of focusing and the second lens group L1 moving to the object side at the time of focusing and having a positive refractive power in order from the object side to the image side. The lens group L2, the third lens group L3 that moves toward the object with a different amount of movement from the second lens group L2 during focusing and has a positive refractive power, and the fourth lens group L4 that has a fixed negative refractive power during focusing. It is composed of and.

The first lens group L1 is a junction lens of a concave meniscus lens having a convex surface facing the object side, a convex meniscus lens having a convex surface facing the object side, and a concave meniscus lens having a convex surface facing the object side in order from the object side to the image side. It is composed of a lens component L1f composed of the above, a convex meniscus lens having a convex surface facing the object side, a junction lens of a biconcave lens and a biconvex lens, and a junction lens of a biconcave lens and a biconvex lens element L1p.

The second lens group L2 is composed of a biconvex lens having both R1 and R2 surfaces aspherical surfaces, and a junction lens of a biconvex lens and a biconcave lens in order from the object side to the image side.

The third lens group L3 includes a junction lens of a biconcave lens and a biconvex lens, a biconvex lens, and a convex meniscus lens in which both R1 and R2 surfaces are aspherical and the concave surface faces the object side, in order from the object side to the image side. Consists of.

The fourth lens group L4 is composed of a junction lens of a biconvex lens and a biconcave lens in order from the object side to the image side.

The aperture stop S is arranged between the second lens group L2 and the third lens group L3, and moves together with the third lens group L3 during focusing.

Subsequently, the specification values of the imaging optical system according to the third embodiment are shown below.

Numerical Example 3
Unit: mm
[Surface data]
Face number rd nd vd
Paraboloid ∞ (d0)
1 172.5357 2.0000 1.51742 52.15
2 47.0409 11.9669 2.00069 25.46
3 250.8344 0.5000
4 172.0419 1.5000 1.74000 28.30
5 35.7808 3.8761
6 46.4746 3.6228 1.83400 37.34
7 61.9501 7.6578
8 -101.6512 1.0000 1.85478 24.80
9 28.1754 18.6827 1.77250 49.62
10 -88.4311 2.2211
11 -61.1945 1.0000 1.65412 39.68
12 39.7645 10.6991 2.00069 25.46
13 -212.9189 d13
14 * 46.5925 9.0306 1.82080 42.71
15 * -191.7122 0.1500
16 376.7369 7.8280 1.49700 81.61
17 -37.7685 1.2257 1.67270 32.17
18 59.8060 d18
(Aperture) ∞ 11.2056
20 -25.2381 1.0000 1.69895 30.05
21 2024.4092 2.3125 1.49700 81.61
22 -2024.4092 0.2000
23 89.8224 6.7907 1.77250 49.62
24 -37.8188 0.2000
25 * -805.5993 2.6710 1.80610 40.73
26 * -69.8617 d26
27 100.6959 5.2583 1.95375 32.32
28 -68.6219 1.5000 1.68893 31.16
29 44.3864 22.5153
30 ∞ 2.5000 1.51680 64.20
31 ∞ BF
Image plane ∞

[Aspherical data]
14 faces 15 faces 25 faces 26 faces
K 0.0000E + 00 0.0000E + 00 0.0000E + 00 0.0000E + 00
A4 6.8204E-07 1.7383E-06 -4.5403E-06 2.2956E-06
A6 5.4170E-10 -1.6259E-09 -1.5798E-08 -1.3371E-08
A8 1.0518E-12 3.1713E-12 7.7418E-11 7.5238E-11
A10 1.2111E-15 -3.6381E-15 -1.1323E-13 -1.0015E-13
A12 0.0000E + 00 0.0000E + 00 0.0000E + 00 0.0000E + 00

[Various data]
INF
Focal length 50.98
F number 1.25
Full angle of view 2ω 45.95
Image height Y 21.63
Lens total length 155.54

[Variable interval data]
INF Shooting distance 2166mm
d0 ∞ 2010.3931
d13 10.4099 8.9153
d18 3.3213 3.6814
d26 1.6952 2.8297
BF 1.0000 1.0000

[Lens group data]
Focal length of group origin
L1 1 999.94
L2 14 96.99
L3 19 59.89
L4 27 -584.50
L1f 1 -195.08

FIG. 16 is a lens configuration diagram of the imaging optical system according to the fourth embodiment at infinity focusing. In the imaging optical system of the fourth embodiment, the first lens group L1 having a fixed positive refractive power at the time of focusing and the second lens group L1 moving to the object side at the time of focusing and having a positive refractive power in order from the object side to the image side. The lens group L2, the third lens group L3 that moves toward the object with a different amount of movement from the second lens group L2 during focusing and has a positive refractive power, and the fourth lens group L4 that has a fixed negative refractive power during focusing. It is composed of and.

In the first lens group L1, in order from the object side to the image side, a concave meniscus lens having a convex surface facing the object side, a convex meniscus lens having a convex surface facing the object side, and an R2 surface side having an aspherical surface and the convex surface facing the object side. A lens component L1f composed of a concave meniscus lens, a convex meniscus lens with a concave surface facing the object side, a junction lens of a biconcave lens and a biconvex lens, a junction lens of a biconcave lens and a biconvex lens, and a biconvex lens element L1p. Consists of.

The second lens group L2 is composed of a biconvex lens having an aspherical surface on the R2 surface side and a junction lens of a biconvex lens and a biconcave lens in order from the object side to the image side.

The third lens group L3 includes a junction lens of a biconcave lens and a biconvex lens, a biconvex lens, and a convex meniscus lens in which both R1 and R2 surfaces are aspherical and the concave surface faces the object side, in order from the object side to the image side. Consists of.

The fourth lens group L4 is composed of a junction lens of a biconvex lens and a biconcave lens in order from the object side to the image side.

The aperture stop S is arranged between the second lens group L2 and the third lens group L3, and moves together with the third lens group L3 during focusing.

Subsequently, the specification values of the imaging optical system according to the fourth embodiment are shown below.

Numerical Example 4
Unit: mm
[Surface data]
Face number rd nd vd
Paraboloid ∞ (d0)
1 302.7931 1.8000 1.55032 75.50
2 39.3515 0.5486
3 38.4312 14.5245 1.90366 31.32
4 336.0760 0.5000
5 160.1565 2.6681 1.58313 59.46
6 * 31.9245 11.4472
7 -86.4442 2.9636 1.49700 81.61
8 -53.2318 0.7438
9 -47.8124 1.5000 1.85478 24.80
10 26.4054 14.2307 1.80610 40.73
11 -74.9982 2.3058
12 -50.3224 1.0000 1.71736 29.50
13 44.6926 7.5348 1.77250 49.62
14 -1000.0000 0.1500
15 80.4108 7.4064 1.92286 20.88
16 -121.8758 d16
17 50.2172 8.0662 1.80610 40.73
18 * -124.4726 0.1500
19 1156.5162 5.4364 1.49700 81.61
20 -58.5090 1.0000 1.62004 36.30
21 45.2228 d21
(Aperture) ∞ 11.6307
23 -27.9465 1.0000 1.71736 29.50
24 56.8941 6.3234 1.49700 81.61
25 -56.8941 0.2000
26 76.8962 7.1654 1.77250 49.62
27 -43.7202 0.2000
28 * -359.1397 2.6914 1.80610 40.73
29 * -68.1807 d29
30 384.5404 4.2749 2.00069 25.46
31 -83.6834 1.5000 1.62004 36.30
32 41.5521 20.8909
33 ∞ 2.5000 1.51680 64.20
34 ∞ BF
Image plane ∞

[Aspherical data]
6 faces 18 faces 28 faces 29 faces
K 0.0000E + 00 0.0000E + 00 0.0000E + 00 0.0000E + 00
A4 8.2952E-07 3.2818E-06 -2.3732E-06 4.6127E-06
A6 -1.1651E-09 -2.0568E-09 -3.5872E-09 -2.7538E-09
A8 1.1925E-11 9.5324E-13 2.1962E-11 1.9733E-11
A10 -2.5631E-14 -3.4704E-16 -6.7271E-14 -5.9502E-14
A12 3.0791E-17 0.0000E + 00 0.0000E + 00 0.0000E + 00

[Various data]
INF
Focal length 41.35
F number 1.26
Full angle of view 2ω 57.17
Image height Y 21.63
Lens total length 157.00

[Variable interval data]
INF Shooting distance 1764mm
d0 ∞ 1607.0621
d16 5.8882 5.0507
d21 4.6652 4.7626
d29 3.0938 3.8339
BF 1.0000 1.0000

[Lens group data]
Focal length of group origin
L1 1 343.31
L2 17 107.54
L3 22 42.17
L4 30 -131.32
L1f 1 -253.36

FIG. 21 is a lens configuration diagram of the imaging optical system according to the fifth embodiment at infinity focusing. In the imaging optical system of the fifth embodiment, the first lens group L1 having a fixed positive refractive power at the time of focusing and the second lens group L1 moving to the object side at the time of focusing and having a positive refractive power in order from the object side to the image side. The lens group L2, the third lens group L3 that moves toward the object with a different amount of movement from the second lens group L2 during focusing and has a positive refractive power, and the fourth lens group L4 that has a fixed negative refractive power during focusing. It is composed of and.

The first lens group L1 includes a lens component L1f composed of a biconcave lens, a convex meniscus lens having a convex surface facing the object side, and a concave meniscus lens having a convex surface facing the object side, in order from the object side to the image side, and an object. It is composed of a convex meniscus lens with a concave surface facing side, a junction lens of a biconcave lens and a biconvex lens, a junction lens of a biconcave lens and a biconvex lens, and a biconvex lens element L1p.

The second lens group L2 is composed of a biconvex lens having an aspherical surface on the R2 surface side and a junction lens of a biconvex lens and a biconcave lens in order from the object side to the image side.

The third lens group L3 includes a junction lens of a biconcave lens and a biconvex lens, a biconvex lens, and a convex meniscus lens in which both R1 and R2 surfaces are aspherical and the concave surface faces the object side, in order from the object side to the image side. Consists of.

The fourth lens group L4 is composed of a junction lens of a biconvex lens and a biconcave lens in order from the object side to the image side.

The aperture stop S is arranged between the second lens group L2 and the third lens group L3, and moves together with the third lens group L3 during focusing.

Subsequently, the specification values of the imaging optical system according to the fifth embodiment are shown below.

Numerical Example 5
Unit: mm
[Surface data]
Face number rd nd vd
Paraboloid ∞ (d0)
1 -221.6420 1.8000 1.65412 39.68
2 39.9381 1.5098
3 41.6329 11.3422 2.00069 25.46
4 359.7585 0.5000
5 168.6543 2.0000 1.49700 81.61
6 39.0895 9.1587
7 -281.5253 3.0747 1.77250 49.62
8 -101.0141 1.1461
9 -76.8612 1.5000 1.85478 24.80
10 26.4054 16.3594 1.80610 40.73
11 -100.2450 3.1496
12 -52.5699 1.0000 1.71736 29.50
13 47.9875 8.9531 1.77250 49.62
14 -318.3701 0.1500
15 73.5723 8.2433 1.92286 20.88
16 -182.2771 d16
17 56.7954 8.0299 1.80610 40.73
18 * -163.6673 0.1500
19 253.0059 8.0482 1.49700 81.61
20 -41.4877 1.0000 1.62004 36.30
21 46.2007 d21
(Aperture) ∞ 12.3310
23 -27.4550 1.0000 1.71736 29.50
24 62.6944 5.6995 1.49700 81.61
25 -62.6944 0.2000
26 68.5803 7.4334 1.77250 49.62
27 -44.3481 0.2000
28 * -624.0167 3.0706 1.80610 40.73
29 * -58.6088 d29
30 4139.7996 2.9899 2.00069 25.46
31 -105.4686 1.5000 1.62004 36.30
32 39.1421 19.5027
33 ∞ 2.5000 1.51680 64.20
34 ∞ BF
Image plane ∞

[Aspherical data]
18 faces 28 faces 29 faces
K 0.0000E + 00 0.0000E + 00 0.0000E + 00
A4 2.2162E-06 -4.4061E-06 4.7866E-06
A6 -1.4446E-09 -1.3022E-08 -1.3568E-08
A8 6.1850E-13 6.3022E-11 6.5030E-11
A10 -5.8575E-16 -8.8313E-14 -8.4692E-14
A12 0.0000E + 00 0.0000E + 00 0.0000E + 00

[Various data]
INF
Focal length 41.35
F number 1.26
Full angle of view 2ω 57.17
Image height Y 21.63
Lens total length 157.00

[Variable interval data]
INF Shooting distance 1828mm
d0 ∞ 1670.8939
d16 5.4917 4.7334
d21 4.6283 4.7723
d29 2.3377 2.9520
BF 1.0000 1.0000

[Lens group data]
Focal length of group origin
L1 1 163.53
L2 17 136.88
L3 22 37.65
L4 30 -83.83
L1f 1 -142.30

FIG. 26 is a lens configuration diagram of the imaging optical system according to the sixth embodiment at infinity focusing. In the imaging optical system of the sixth embodiment, the first lens group L1 having a fixed positive refractive power at the time of focusing and the second lens group L1 moving to the object side at the time of focusing and having a positive refractive power in order from the object side to the image side. The lens group L2, the third lens group L3 that moves toward the object with a different amount of movement from the second lens group L2 during focusing and has a positive refractive power, and the fourth lens group L4 that has a fixed negative refractive power during focusing. It is composed of and.

The first lens group L1 consists of a concave meniscus lens having a convex surface facing the object side, a convex meniscus lens having a convex surface facing the object side, and both R1 and R2 surfaces having aspherical surfaces and facing the object side in order from the object side to the image side. A lens component L1f composed of a concave meniscus lens with a convex surface, a convex meniscus lens with a concave surface facing the object side, a junction lens of a biconcave lens and a biconvex lens, and a concave meniscus lens with a convex surface facing the object side. It is composed of a junction lens of a biconvex lens and a biconvex lens element L1p.

The second lens group L2 is composed of a biconvex lens having both R1 and R2 surfaces aspherical surfaces, and a junction lens of a biconvex lens and a biconcave lens in order from the object side to the image side.

The third lens group L3 includes a junction lens of a biconcave lens and a biconvex lens, a biconvex lens, and a convex meniscus lens in which both R1 and R2 surfaces are aspherical and the concave surface faces the object side, in order from the object side to the image side. Consists of.

The fourth lens group L4 is composed of a convex meniscus lens having a concave surface facing the object side and a junction lens of both concave lenses in order from the object side to the image side.

The aperture stop S is arranged between the second lens group L2 and the third lens group L3, and moves together with the third lens group L3 during focusing.

Subsequently, the specification values of the imaging optical system according to the sixth embodiment are shown below.

Numerical Example 6
Unit: mm
[Surface data]
Face number rd nd vd
Paraboloid ∞ (d0)
1 208.7963 1.8000 1.55032 75.50
2 37.5679 2.7643
3 45.0047 6.0937 1.90366 31.32
4 109.3983 0.5000
5 * 78.5119 1.6663 1.58313 59.46
6 * 31.4439 9.9385
7 -70.9895 1.8501 2.00069 25.46
8 -62.6798 1.7867
9 -42.2155 1.5004 1.80518 25.46
10 31.3468 9.5060 1.77250 49.62
11 -292.0488 0.2000
12 276.7254 1.0000 1.68893 31.16
13 44.2467 8.1039 1.77250 49.62
14 -290.6421 0.1500
15 64.5740 7.5729 1.92286 20.88
16 -177.0858 d16
17 * 87.5103 5.5489 1.80610 40.73
18 * -136.1628 0.1500
19 785.1137 5.2948 1.49700 81.61
20 -58.4639 1.0000 1.62004 36.30
21 74.9789 d21
(Aperture) ∞ 10.9090
23 -25.5428 1.0000 1.71736 29.50
24 39.9980 8.1122 1.49700 81.61
25 -39.9980 0.2000
26 66.0200 7.6222 1.77250 49.62
27 -44.3960 1.0844
28 * -500.0000 4.4095 1.80610 40.73
29 * -63.0102 d29
30 -652.6258 3.0248 2.00069 25.46
31 -120.1715 1.5000 1.62004 36.30
32 37.3343 18.5186
33 ∞ 2.5000 1.51680 64.20
34 ∞ BF
Image plane ∞

[Aspherical data]
5 sides 6 sides 17 sides
K 0.0000E + 00 0.0000E + 00 0.0000E + 00
A4 -2.4193E-06 -2.5703E-06 -6.1262E-07
A6 4.2279E-09 5.9920E-10 -9.4062E-10
A8 -6.4066E-13 2.0057E-11 8.8650 E-13
A10 -6.3635E-15 -4.2154E-14 6.6622E-16
A12 1.7532E-18 2.9611E-17 0.0000E + 00

18 faces 28 faces 29 faces
K 0.0000E + 00 0.0000E + 00 0.0000E + 00
A4 1.8077E-06 -4.3710E-06 4.0846E-06
A6 -2.0087E-09 -8.1297E-09 -8.8949E-09
A8 2.3893E-12 3.9617E-11 3.9681E-11
A10 -6.7002E-16 -5.2134E-14 -4.4640E-14
A12 0.0000E + 00 0.0000E + 00 0.0000E + 00

[Various data]
INF
Focal length 35.99
F number 1.26
Full angle of view 2ω 64.62
Image height Y 21.63
Lens total length 140.00

[Variable interval data]
INF Shooting distance 1709mm
d0 ∞ 1569.2220
d16 7.1633 6.5587
d21 3.3810 3.5102
d29 3.1483 3.6237
BF 1.0000 1.0000

[Lens group data]
Focal length of group origin
L1 1 95.94
L2 17 162.29
L3 22 33.81
L4 30 -66.76
L1f 1 -94.79

FIG. 31 is a lens configuration diagram of the imaging optical system according to the seventh embodiment at infinity focusing. In the imaging optical system of the seventh embodiment, the first lens group L1 having a fixed positive refractive power at the time of focusing and the second lens group L1 moving to the object side at the time of focusing and having a positive refractive power in order from the object side to the image side. The lens group L2, the third lens group L3 that moves toward the object with a different amount of movement from the second lens group L2 during focusing and has a positive refractive power, and the fourth lens group L4 that has a fixed negative refractive power during focusing. It is composed of and.

The first lens group L1 consists of a concave meniscus lens having a convex surface facing the object side, a convex meniscus lens having a convex surface facing the object side, and both R1 and R2 surfaces having aspherical surfaces and facing the object side in order from the object side to the image side. A lens component L1f composed of a concave meniscus lens with a convex surface, a convex meniscus lens with a concave surface facing the object side, a junction lens of a biconcave lens and a biconvex lens, and a concave meniscus lens with a convex surface facing the object side. It is composed of a junction lens of a biconvex lens and a biconvex lens element L1p.

The second lens group L2 is composed of a biconvex lens having both R1 and R2 surfaces aspherical surfaces, and a junction lens of a biconvex lens and a biconcave lens in order from the object side to the image side.

The third lens group L3 includes a junction lens of a biconcave lens and a biconvex lens, a biconvex lens, and a convex meniscus lens in which both R1 and R2 surfaces are aspherical and the concave surface faces the object side, in order from the object side to the image side. Consists of.

The fourth lens group L4 is composed of a convex meniscus lens having a concave surface facing the object side and a junction lens of both concave lenses in order from the object side to the image side.

The aperture stop S is arranged between the second lens group L2 and the third lens group L3, and moves together with the third lens group L3 during focusing.

Subsequently, the specification values of the imaging optical system according to the seventh embodiment are shown below.

Numerical Example 7
Unit: mm
[Surface data]
Face number rd nd vd
Paraboloid ∞ (d0)
1 226.6509 1.8000 1.55032 75.50
2 37.1876 4.0192
3 55.4122 4.7294 1.90366 31.32
4 116.5808 0.6495
5 * 83.0956 1.5000 1.58313 59.46
6 * 37.5827 9.2166
7 -67.9565 1.7989 2.00069 25.46
8 -62.1377 1.7966
9 -42.9597 1.5000 1.80518 25.46
10 33.3896 9.3826 1.77250 49.62
11 -1000.0000 0.2000
12 142.2232 1.0000 1.68893 31.16
13 54.6257 8.6236 1.77250 49.62
14 -141.4848 0.1500
15 66.8094 7.4639 1.92286 20.88
16 -284.8140 d16
17 * 77.8044 6.3056 1.80610 40.73
18 * -135.9548 0.1500
19 496.0114 6.3427 1.49700 81.61
20 -48.9846 1.0000 1.62004 36.30
21 60.3510 d21
(Aperture) ∞ 10.8113
23 -25.3434 1.0000 1.71736 29.50
24 40.9982 8.0446 1.49700 81.61
25 -40.9982 0.2000
26 66.4770 7.5449 1.77250 49.62
27 -43.4716 0.2000
28 * -500.0000 2.9945 1.80610 40.73
29 * -64.9199 d29
30 -1421.9197 2.5574 2.00069 25.46
31 -220.5750 1.5000 1.62004 36.30
32 39.7560 19.8809
33 ∞ 2.5000 1.51680 64.20
34 ∞ BF
Image plane ∞

[Aspherical data]
5 sides 6 sides 17 sides
K 0.0000E + 00 0.0000E + 00 0.0000E + 00
A4 -2.9369E-06 -2.8547E-06 -3.5602E-07
A6 3.6527E-09 1.1812E-09 -2.3057E-10
A8 3.2827E-12 1.9490E-11 1.0239E-12
A10 -1.5316E-14 -4.1538E-14 4.6815E-16
A12 5.5604E-18 2.0280E-17 0.0000E + 00

18 faces 28 faces 29 faces
K 0.0000E + 00 0.0000E + 00 0.0000E + 00
A4 2.0936E-06 -3.6957E-06 4.3899E-06
A6 -1.6258E-09 -1.3659E-08 -1.4085E-08
A8 2.4213E-12 5.7018E-11 5.7420E-11
A10 -1.3280E-15 -7.1752E-14 -6.5525E-14
A12 0.0000E + 00 0.0000E + 00 0.0000E + 00

[Various data]
INF
Focal length 35.99
F number 1.26
Full angle of view 2ω 64.60
Image height Y 21.63
Lens total length 140.00

[Variable interval data]
INF Shooting distance 1646mm
d0 ∞ 1505.6085
d16 7.1493 6.5282
d21 3.8600 3.9906
d29 3.1285 3.6190
BF 1.0000 1.0000

[Lens group data]
Focal length of group origin
L1 1 91.85
L2 17 173.52
L3 22 34.05
L4 30 -68.63
L1f 1 -83.09

FIG. 36 is a lens configuration diagram of the imaging optical system according to the eighth embodiment at infinity focusing. In the imaging optical system of the eighth embodiment, the first lens group L1 having a fixed positive refractive power at the time of focusing and the second lens group L1 moving to the object side at the time of focusing and having a positive refractive power in order from the object side to the image side. The lens group L2, the third lens group L3 that moves toward the object with a different amount of movement from the second lens group L2 during focusing and has a positive refractive power, and the fourth lens group L4 that has a fixed negative refractive power during focusing. It is composed of and.

The first lens group L1 consists of a concave meniscus lens having a convex surface facing the object side in order from the object side to the image side, a convex meniscus lens having a convex surface facing the object side, and a concave lens having an aspherical surface on the R1 surface side and having a convex surface facing the object side. It is composed of a lens component L1f composed of a meniscus lens, a convex meniscus lens having a convex surface facing the object side, a junction lens of a biconcave lens and a biconvex lens, a biconvex lens, and a biconvex lens element L1p.

The second lens group L2 is composed of a biconvex lens having both R1 and R2 surfaces aspherical surfaces, and a junction lens of a biconvex lens and a biconcave lens in order from the object side to the image side.

The third lens group L3 includes a junction lens of a biconcave lens and a biconvex lens, a biconvex lens, and a convex meniscus lens in which both R1 and R2 surfaces are aspherical and the concave surface faces the object side, in order from the object side to the image side. Consists of.

The fourth lens group L4 is composed of a junction lens of a biconvex lens and a biconcave lens in order from the object side to the image side.

The aperture stop S is arranged between the second lens group L2 and the third lens group L3, and moves together with the third lens group L3 during focusing.

Subsequently, the specification values of the imaging optical system according to the eighth embodiment are shown below.

Numerical Example 8
Unit: mm
[Surface data]
Face number rd nd vd
Paraboloid ∞ (d0)
1 81.2891 1.8000 1.55032 75.50
2 28.9027 0.1500
3 28.2387 4.3344 2.00069 25.46
4 29.1180 9.5131
5 * 158.8717 1.5000 1.55332 71.68
6 62.5908 2.1314
7 89.6194 2.3707 2.00069 25.46
8 137.3005 6.6417
9 -42.7735 1.5000 1.85478 24.80
10 38.3152 8.6871 1.77250 49.62
11 -1000.0000 0.2000
12 101.1960 5.9343 1.77250 49.62
13 -122.4102 0.1500
14 134.7565 5.4178 2.00272 19.32
15 -167.3230 d15
16 * 47.8348 7.9022 1.77250 49.50
17 * -174.6859 0.1500
18 316.6676 7.6993 1.49700 81.61
19 -37.0753 1.0000 1.59551 39.24
20 43.0544 d20
21 ∞ 7.3558
(Aperture) -25.9789 1.0000 1.75520 27.53
23 103.0615 4.4073 1.49700 81.61
24 -103.0615 0.2000
25 83.2463 6.8030 1.77250 49.62
26 -39.5088 0.2000
27 * -500.0000 3.7949 1.80610 40.73
28 * -56.0409 d28
29 106.5408 4.5062 2.00069 25.46
30 -104.2136 1.5000 1.75520 27.53
31 42.8987 21.6282
32 ∞ 2.5000 1.51680 64.20
33 ∞ BF
Image plane ∞

[Aspherical data]
5 sides 16 sides 17 sides 27 sides 28 sides
K 0.0000E + 00 0.0000E + 00 0.0000E + 00 0.0000E + 00 0.0000E + 00
A4 -1.3861E-07 3.9344E-07 2.7239E-06 -4.8096E-06 3.5677E-06
A6 7.4960E-10 6.4953E-10 -1.6905E-09 -6.1663E-09 -3.9779E-09
A8 -6.1209E-12 5.6179E-13 8.4103E-13 4.6850E-11 4.1745E-11
A10 1.1405E-14 -4.0245E-16 -1.8737E-15 -8.1995E-14 -6.4477E-14
A12 -1.0449E-17 0.0000E + 00 0.0000E + 00 0.0000E + 00 0.0000E + 00

[Various data]
INF
Focal length 35.99
F number 1.26
Full angle of view 2ω 64.09
Image height Y 21.63
Lens total length 140.00

[Variable interval data]
INF Shooting distance 1565mm
d0 ∞ 1425.1600
d15 9.3606 8.4796
d20 5.9272 6.1089
d28 2.7346 3.4339
BF 1.0000 1.0000

[Lens group data]
Focal length of group origin
L1 1 266.97
L2 16 118.15
L3 21 45.62
L4 29 -186.66
L1f 1 -67.03

The following [Conditional Expression Corresponding Value] shows a list of corresponding values of each embodiment corresponding to each conditional expression.

[Conditional expression correspondence value]
Conditional expression 1 Conditional expression 2 Conditional expression 3 Conditional expression 4
Example Y / Bf LT / f | ΣAci | vdL1p
1 1.01 3.02 0.0004 25.46
2 0.99 3.04 0.0001 25.46
3 0.83 3.05 0.0001 25.46
4 0.89 3.80 0.0018 20.88
5 0.94 3.80 0.0015 20.88
6 0.98 3.89 0.0012 20.88
7 0.93 3.89 0.0011 20.88
8 0.86 3.89 0.0013 19.32

Conditional expression 5 Conditional expression 6 Conditional expression 7 Conditional expression 8
Example ΔPgfL1p Fno ・ (f3 / f) f1f / f B1b
1 0.0108 1.48 -3.62 0.10
2 0.0108 1.51 -3.74 0.12
3 0.0108 1.47 -3.83 0.05
4 0.0283 1.28 -6.13 0.12
5 0.0283 1.14 -3.44 0.25
6 0.0283 1.18 -2.63 0.38
7 0.0283 1.19 -2.31 0.39
8 0.0315 1.59 -1.86 0.13

As is clear from the various aberration diagrams of each embodiment, according to the present invention, spherical aberration and axial chromatic aberration, which have been problems of the conventional imaging optical system, are satisfactorily corrected, the back focus is short, and the F value is F1. It is possible to provide an optimum imaging optical system for a mirrorless camera of about 2.

L1 1st lens group L2 2nd lens group L3 3rd lens group L4 4th lens group L1f Lens component L1f
L1p Lens element L1p
S Open aperture LPF Low-pass filter I Image plane

Claims (4)

From the object side to the image side, in order
The first lens group L1 having a positive refractive power and
The second lens group L2 having a positive refractive power,
The third lens group L3 having a positive refractive power,
It consists of a fourth lens group L4 having a negative refractive power.
The first lens group L1 has at least one bonded lens, and has a lens element having the most negative refractive power on the object side, and the lens element having a positive refractive power with a convex surface facing the object side. Arranged so as to be adjacent to the image side of the lens element having a negative refractive power.
At the time of focusing, the second lens group L2 and the third lens group L3 move toward the object side by different amounts of movement, and the first lens group L1 and the fourth lens group L4 move with respect to the image plane. The lens component L1f is from the most object-side surface of the first lens group L1 to the image-side surface of the lens element having a negative refractive power with the convex surface facing the object side, and the lens component L1f is negative. Imaging optical system Y / Bf> 0.80 (1) , which has the refractive power of
LT / f <4.20 (2)

-7.96 <f1f / f <-1.33 (7)
however,
Y is the maximum image height,
Bf is the distance from the top of the surface on the image side of the fourth lens group L4 to the image surface.
LT is the distance from the top of the surface of the first lens group L1 on the most object side to the image plane.
f is the focal length of the entire lens system at infinity focusing ,
f1f is the focal length of the lens component L1f .
Aci is expressed by the following equation.
Aci = φcpi / νdcpi + φcmi / νdcmi
however,
φcpi is the refractive power of the convex lens element of the i-th junction lens from the object side included in the first lens group L1.
νdcpi is the Abbe number of the convex lens element of the i-th junction lens from the object side included in the first lens group L1.
φcmi is the refractive power of the concave lens element of the i-th junction lens from the object side included in the first lens group L1.
νdcmi is the Abbe number of the concave lens element of the i-th junction lens from the object side included in the first lens group L1.
The imaging optical system νdL1p <30 (4) according to claim 1, wherein the lens element L1p having a positive refractive power arranged on the most image side of the first lens group L1 satisfies the following conditional expression. )
0.0090 <ΔPgfL1p (5)
however,
ΔPgfL1p is the anomalous dispersibility of the positive lens element L1p and is expressed by the following equation.
ΔPgfL1p = PgfL1p + 0.0018 × νdL1p −0.64833
however,
νdL1p is the Abbe number νd of the positive lens element L1p.
PgfL1p is a partial dispersion ratio Pgf with respect to the g-line and the F-line of the positive lens element L1p.
The imaging optical system according to claim 1 or 2, wherein the imaging optical system satisfies the following conditional expression.
0.88 <Fno ・ (f3 / f) <1.96 (6)
however,
Fno is the F value of the entire lens system when focusing at infinity,
f3 is the focal length of the third lens group L3,
f is the focal length of the entire lens system at infinity focusing.
The imaging optical system according to any one of claims 1 to 3 , wherein the imaging optical system satisfies the following conditional expression.
β1b <0.50 (8)
however,
β1b is the lateral magnification of the lens system arranged on the image side of the first lens group L1 at the time of infinity focusing.

Images