JP7093523B2 - Shooting lens - Google Patents

Description

The present invention relates to an optical system and is suitable for a shooting lens used in a shooting device such as a digital still camera, a digital video camera, or a cinema camera.

The photographic optical system used in optical equipment such as digital cameras is required to have a large diameter ratio so as to be able to handle high-speed shooting and expressions that make use of large blur. Further, with the recent increase in the number of pixels of CCD / CMOS sensors, it is required to further correct various aberrations and achieve high performance.

Conventionally, short focus lenses often take the retrofocus type because it is necessary to secure sufficient back focus. A photographic lens that uses a retrofocus type to achieve a large aperture ratio and high performance is known.

JP-A-2017-227799 JP 2014-123018

The optical system disclosed in Patent Document 1 makes extensive use of aspherical surfaces to achieve both miniaturization and high performance, but since it adopts a typical double gauss type before and after the aperture, it is before and after the aperture. There is a problem that the correction of the sagittal coma flare generated in the facing concave surfaces is insufficient.

The optical system disclosed in Patent Document 2 realizes a large diameter ratio of about F1.4 and high-speed focusing after making the front and rear apertures a non-double Gauss type, but it has axial chromatic aberration and sagittal coma flare. There is a problem that the correction of various aberrations including the above is insufficient.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a photographing lens which is as bright as F1.4 and has well corrected various aberrations such as sagittal coma flare.

The first invention for solving the above-mentioned problems is composed of a front group Gf having a positive refractive power, an opening aperture S, and a rear group Gr having a positive refractive power in order from the object side, and the front group Gf. The positive lens Lf1 and the negative lens Lf2 are joined to the most image side, and the lens component Lfb with the concave surface facing the image side is arranged. A photographing lens characterized by having a lens component Lra having a convex surface facing the object side and having a negative refractive power as a whole, a negative lens Lr3 having a concave surface facing the object side, and a positive lens Lr4, and satisfying the following conditional expression. ..
(1) 1.6 ≤ Fr / F <2.5
(2) -0.7 <100 x (N2-N1) / (V2-V1) <-0.05
Fr: Focal length of the rear group Gr: Focal length of the whole system N1: Refractive index of Lr1 N2: Refractive index of Lr2 V1: Abbe number of Lr1 V2: Abbe number of Lr2

The second invention is the photographing lens according to the first invention, wherein the Lr1 satisfies the following conditional expression.
(3) PgFr1- (-0.0018 × V1 + 0.6483)> 0
PgFr1: Partial dispersion ratio of the positive lens Lr1 V1: Abbe number of the Lr1

The third invention is the first invention or the second invention, wherein the positive lens Lf1 constituting the lens component Lfb arranged on the most image side of the front group Gf satisfies the following conditional expression. The shooting lens described in.
(4) Vf1> 50
(5) PgFf1- (-0.0018 x Vf1 + 0.6483)> 0
Vf1: Abbe number of the positive lens Lf1 PgFf1: Partial dispersion ratio of the positive lens Lf1

The fourth invention is the photographing lens according to any one of the first invention to the third invention, which is characterized by satisfying the following conditional expression.
(6) -15 <(R_fi + R_ro) / (R_fi-R_ro) <-1
R_fi: Radius of curvature of the most image-side surface of the front group Gf R_ro: Radius of curvature of the most object-side surface of the rear group Gr

The fifth invention is the photographing lens according to any one of the first invention to the fourth invention, which is characterized by satisfying the following conditional expression.
(7) -0.9 <Fr × (N2-N1) /Rac <-0.05
Fr: Focal length of the rear group Gr: Refractive index of Lr1 N2: Refractive index of Lr2 Rac: Radius of curvature of the junction surface of the lens component Lra

The sixth invention is the photographing lens according to any one of the first invention to the fifth invention, which is characterized by satisfying the following conditional expression.
(8) -1.8 <R_L31 / D <-1.0
R_Lr31: Radius of curvature D on the object side of the negative lens Lr3: Distance on the optical axis from the aperture stop S to the surface of the negative lens Lr3 on the object side.

The seventh invention is the photographing lens according to any one of the first invention to the sixth invention, which is characterized by satisfying the following conditional expression.
(9) Npave <1.75
Npave: Mean value of the refractive index of the positive lens included in the rear group Gr

Eighth invention according to any one of the first to seventh inventions, wherein the rear group Gr has at least one aspherical surface in which the negative refractive power becomes stronger as the distance from the optical axis increases. Shooting lens.

In the ninth invention, the front group Gf is composed of a first lens group Gf1 having a positive or negative refractive power and a second lens group Gf2 having a positive refractive power in order from the object side, from infinity to close range. The first invention to the eighth, characterized in that the first lens group Gf1 is fixed to an image plane during focusing, and the second lens group Gf2 and the rear group Gr move toward an object on the optical axis. The photographing lens according to any one of the inventions of.

INDUSTRIAL APPLICABILITY The present invention makes it possible to provide a photographing lens which is as bright as F1.4 and which is satisfactorily corrected for various aberrations such as sagittal coma flare.

It is a lens block diagram which concerns on Example 1 of the photographing lens of this invention. It is a longitudinal aberration diagram at the shooting distance infinity of the shooting lens of the first embodiment. It is a longitudinal aberration diagram at a shooting distance of 392 mm of the shooting lens of Example 1. It is a lateral aberration diagram at the shooting distance infinity of the shooting lens of the first embodiment. FIG. 3 is a lateral aberration diagram at a shooting distance of 392 mm of the shooting lens of the first embodiment. It is a lens block diagram which concerns on Example 2 of the photographing lens of this invention. It is a longitudinal aberration diagram at the shooting distance infinity of the shooting lens of the second embodiment. It is a longitudinal aberration diagram at a shooting distance of 392 mm of the shooting lens of Example 2. It is a lateral aberration diagram at the shooting distance infinity of the shooting lens of the second embodiment. FIG. 3 is a lateral aberration diagram at a shooting distance of 392 mm of the shooting lens of the second embodiment. It is a lens block diagram which concerns on reference example 3 of the photographing lens of this invention. It is a longitudinal aberration diagram at an infinity shooting distance of the shooting lens of Reference Example 3. It is a longitudinal aberration diagram at a shooting distance of 392 mm of the shooting lens of Reference Example 3. It is a lateral aberration diagram at an infinity shooting distance of the shooting lens of Reference Example 3. It is a lateral aberration diagram at a shooting distance of 392 mm of the shooting lens of Reference Example 3. It is a lens block diagram which concerns on Example 4 of the photographing lens of this invention. It is a longitudinal aberration diagram at the shooting distance infinity of the shooting lens of the fourth embodiment. It is a longitudinal aberration diagram at a shooting distance of 390 mm of the shooting lens of Example 4. It is a lateral aberration diagram at a shooting distance infinity of the shooting lens of Example 4. It is a lateral aberration diagram at a shooting distance of 390 mm of the shooting lens of Example 4. It is a lens block diagram which concerns on Example 5 of the photographing lens of this invention. It is a longitudinal aberration diagram at the shooting distance infinity of the shooting lens of Example 5. It is a longitudinal aberration diagram at a shooting distance of 373 mm of the shooting lens of Example 5. It is a lateral aberration diagram at a shooting distance infinity of the shooting lens of Example 5. FIG. 3 is a lateral aberration diagram at a shooting distance of 373 mm of the shooting lens of Example 5. It is a lens block diagram which concerns on Example 6 of the photographing lens of this invention. It is a longitudinal aberration diagram at the shooting distance infinity of the shooting lens of Example 6. It is a longitudinal aberration diagram at a shooting distance of 373 mm of the shooting lens of Example 6. It is a lateral aberration diagram at a shooting distance infinity of the shooting lens of Example 6. FIG. 3 is a lateral aberration diagram at a shooting distance of 373 mm of the shooting lens of Example 6.

Hereinafter, the photographing lens according to the embodiment of the present invention will be described. When the refractive indexes of the materials for the g-line, F-line, d-line, and C-line are Ng, NF, Nd, and NC, respectively, the Abbe number Vd for the d-line of the material and the portion between the g-line and the F-line are obtained. The dispersion ratio PgF is represented below.
Vd = (Nd-1) / (NF-NC)
PgF = (Ng-NF) / (NF-NC)

As can be seen from the lens configuration diagrams shown in FIGS. 1, 6, 11, 16, 21, and 26, the photographing lens of the present invention has a front group Gf having a positive refractive force in order from the object side to the image side. , Aperture aperture S, rear group Gr having a positive refractive force, and a lens component Lfb in which a positive lens Lf1 and a negative lens Lf2 are joined and a concave surface is directed toward the image side is arranged on the most image side of the front group Gf. In the rear group Gr, the positive lens Lr1 and the negative lens Lr2 are joined in this order from the object side to the image side, and the negative lens component Lra with the convex surface facing the object side, the negative lens Lr3 with the concave surface facing the object side, and the positive lens Lr3. It has a lens Lr4 and is characterized by satisfying the following conditional expression.
(1) 1.3 <Fr / F <2.5
(2) -0.7 <100 x (N2-N1) / (V2-V1) <-0.05
F: Focal length of the whole system Fr: Focal length of the rear group Gr N1: Refractive index of the glass material of Lr1 N2: Refractive index of the glass material of Lr2 V1: Abbe number of the glass material of Lr1 V2: Abbe number of the glass material of Lr2

In the present application, the lens component represents a single lens or a bonded lens obtained by joining a plurality of lenses.

The optical system of the present invention is characterized in that various aberrations such as sagittal coma flare, which is a problem of the double Gauss type, are satisfactorily corrected by adopting a non-double Gauss type before and after the aperture.

Higher-order aberrations such as peripheral spherical aberration are known as the cause of the characteristic flare, which is widely called sagittal coma flare and is sometimes described as "spreading the wings of a bird". This increases as the aperture increases and the angle of view increases. Further, it is known that sagittal coma flare is likely to occur on a surface having a tight curvature or a surface having a large surface power, for example, on a surface having a tight concave surface facing each other before and after the aperture in the double gauss type.

On the other hand, one of the advantages of the double Gauss type is the ease of correction of spherical aberration and astigmatism. Therefore, it is desirable to reduce sagittal coma flare while maintaining the advantages of the double-Gauss type, and it is possible to satisfactorily correct various aberrations and obtain a high-resolution image over the entire angle of view.

By the way, in the region of tertiary aberration, each aberration coefficient is calculated individually for each surface, but in the case of higher-order aberration, the contribution of the surface before that surface cannot be ignored. In the double gauss type, the concave surface before the aperture has a strong effect on the concave surface after the aperture. Therefore, if a new lens component is inserted just before the concave surface behind the aperture and the path of the light beam is adjusted appropriately, it becomes possible to reduce sagittal coma flare while maintaining good astigmatism and spherical aberration. It is desirable that the lens component to be inserted here is a junction lens component having a negative power. This is because having a negative power makes it possible to share the aberration correction of the concave surface before or after the aperture, and since there are more surfaces than a single lens and the degree of freedom is increased, more effective aberration correction becomes possible.

The optical system of the present invention is based on the above considerations, and by arranging the junction lens component immediately after the aperture and directing the convex surface toward the object side, aberration correction having a character different from that of the typical double gauss type can be performed. It is possible.

First, since the optical system of the present invention is asymmetrical before and after the aperture, the aberrations to be corrected are divided between the front group and the rear group to obtain good aberration correction for the entire system. Conditional expression (1) defines an appropriate power distribution for the entire system.

If the difference in height between the axial ray and the peripheral main ray in the front group becomes smaller than the upper limit of the conditional expression (1), the role of aberration correction cannot be divided, which is not preferable. Further, if the power of the rear group Gr becomes stronger beyond the lower limit of the conditional expression (1), spherical aberration is particularly deteriorated, which is not preferable.

Regarding the conditional expression (1), it is desirable to set the upper limit value to 2. By setting it to 0 , the above-mentioned effect can be further ensured.

The junction negative lens component Lra is placed on the most object side of the rear group Gr. Lra not only contributes to the correction of axial chromatic aberration, but also contributes to the correction of spherical aberration and astigmatism of the negative lens Lr3. Generally, in order for a junction lens consisting of two positive and negative lenses to have negative power as a whole, it is necessary to weaken the power of the positive lens and increase the power of the negative lens. Therefore, in Lra, it is desirable to use a low refractive index glass material for the positive lens and a high refractive index glass material for the negative lens to make the so-called old achromatic material.

The conditional expression (2) defines the two glass materials of Lra in order to have the above-mentioned role.

When the difference in refractive index becomes smaller than the upper limit of the conditional expression (2), the negative power of Lra as a whole becomes too small, and the incident angles of the axial and peripheral marginal rays on the surface of Lr3 on the object side become large. , Spherical aberration and coma are worsened. If the Abbe number difference becomes smaller than the lower limit of the conditional expression (2), axial chromatic aberration worsens, which is not preferable.

Regarding the conditional expression (2), preferably the upper limit value is -0.1, more preferably the upper limit value is -0.2, and the lower limit value is -0.5, and further preferably the lower limit value is -0.4. For example, the above-mentioned effect can be more ensured.

The optical system of the present invention is characterized by satisfying the following conditional expression.
(3) PgFr1- (-0.0018 × V1 + 0.6483)> 0
Abbe number of glass material with PgFr1: partial dispersion ratio V1: Lr1 of positive lens Lr1

Conditional expression (3) defines the glass material of Lr1 for correcting axial chromatic aberration, especially the secondary spectrum. Since Lr1 is close to the aperture, the secondary spectrum can be satisfactorily corrected without deteriorating the chromatic aberration of magnification by using a glass material having high anomalous dispersibility.

If the anomalous dispersibility becomes smaller than the lower limit of the conditional expression (3), the correction of the secondary spectrum becomes insufficient, which is not preferable.

Desirably, by setting the lower limit value of the conditional expression (3) to 0.01, the above-mentioned effect can be further ensured.

The optical system of the present invention is characterized by satisfying the following conditional expression.
(4) Vf1> 50
(5) PgFf1- (-0.0018 x Vf1 + 0.6483)> 0
Vf1: Abbe number of positive lens Lf1 PgFf1: Partial dispersion ratio of positive lens Lf1

The conditional expression (4) and the conditional expression (5) define the glass material of the positive lens Lf1 constituting the junction lens Lfb in order to satisfactorily correct the axial chromatic aberration. Generally, the on-axis ray is high and the peripheral main ray is low near the aperture. By using a glass material having a high Abbe number and high anomalous dispersibility for the positive lens immediately before the aperture, it is possible to satisfactorily correct the axial chromatic aberration without deteriorating the chromatic aberration of magnification.

If the Abbe number becomes smaller than the lower limit of the conditional expression (4), the correction of axial chromatic aberration becomes insufficient, which is not preferable.

If the anomalous dispersibility becomes smaller than the lower limit of the conditional expression (5), the correction of the secondary spectrum becomes insufficient, which is not preferable.

Desirably, by setting the lower limit value of the conditional expression (4) to 60, the above-mentioned effect can be further ensured.

Further, by setting the lower limit value of the conditional expression (5) to 0.005, the above-mentioned effect can be further ensured.

The optical system of the present invention is characterized by satisfying the following conditional expression.
(6) -15 <(R_fi + R_ro) / (R_fi-R_ro) <-1
R_fi: Radius of curvature of the surface of the front group Gf on the most image side R_ro: Radius of curvature of the surface of the rear group Gr on the most object side

Conditional expression (6) defines the relationship between the radii of curvature of the two surfaces before and after the aperture in order to correct spherical aberration and astigmatism in a well-balanced manner.

If the convex surface on the most object side of Lra becomes loose beyond the upper limit of the conditional expression (6), spherical aberration becomes overcorrected, which is not preferable.

If the convex surface of Lra on the most object side becomes tighter than the lower limit of the conditional expression (6), astigmatism worsens, which is not preferable.

With respect to the range of the conditional expression (6), preferably, if the upper limit value is −1.5 and the lower limit value is −10, the effect can be further ensured.

The optical system of the present invention is characterized by satisfying the following conditional expression.
(7) -0.9 <Fr × (N2-N1) /Rac <-0.05
Fr: Focal length of the rear group Gr N1: Refractive index of the glass material of Lr1 N2: Refractive index of the glass material of Lr2 Rac: Radius of curvature of the joint surface of Lra

The conditional expression (7) specifies the surface power of the joint surface of Lra in order to particularly satisfactorily correct the sagittal coma flare.

The joint surface of Lra can be regarded as the image-side surface of the positive lens Lr1 and the object-side surface of the negative lens Lr2. If the curvature of the joint surface is loosened while maintaining the power of the entire Lra, the curvature of the surface of the positive lens Lr1 on the object side and the surface of the negative lens Lr2 on the image side will eventually be in order to maintain the respective powers of Lr1 and Lr2. It gets tight.

If the surface power of the joint surface becomes weaker than the upper limit of the conditional expression (7), the curvature of the surface on the most image side of Lra becomes tight to compensate for it, which causes deterioration of sagittal coma flare, which is not preferable.

If the curvature of the joint surface becomes too tight beyond the lower limit of the conditional expression (7), the convex surface on the most object side of Lra becomes too loose, which is not preferable because spherical aberration is particularly deteriorated.

The effect of the conditional expression (7) can be ensured by preferably setting the lower limit value to -0.6 and further setting the upper limit value to -0.2.

The optical system of the present invention is characterized by satisfying the following conditional expression.
(8) -1.8 <R_Lr31 / D <-1.0
R_Lr31: Radius of curvature D on the object side of the negative lens Lr3: Distance on the optical axis from the aperture to the surface of the negative lens Lr3 on the object side.

The conditional expression (8) defines the position of the negative lens Lr3 and the radius of curvature as conditions for satisfactorily correcting the sagittal coma flare while suppressing astigmatism. Here, the distance on the optical axis is positive in the direction toward the image plane.

If the curvature of the surface of the negative lens Lr3 on the object side exceeds the upper limit of the conditional expression (8), the height of the peripheral main rays incident on the surface becomes too high, which leads to deterioration of sagittal coma flare in particular.

If the curvature of the object-side surface of the negative lens Lr3 becomes loose beyond the lower limit of the conditional expression (8), the object-side surface of the negative lens Lr3 does not become concentric with respect to the aperture, and astigmatism worsens. Not preferred.

With respect to the conditional expression (8), preferably, the lower limit value is set to -1.7 and the upper limit value is set to -1.1, so that the effect can be further ensured.

The optical system of the present invention is characterized by satisfying the following conditional expression.
(9) Npave <1.75
Npave: Mean value of the refractive index of the positive lens included in the rear group Gr

The conditional expression (9) defines the glass material of the positive lens included in the rear group Gr in order to correct the axial chromatic aberration. Many glass materials with a low refractive index and a high Abbe number have high anomalous dispersibility and are effective for secondary spectral correction.

If the upper limit of the conditional expression (9) is exceeded, the secondary spectrum deteriorates, which is not preferable.

Desirably, the effect can be ensured by setting the upper limit value of the conditional expression (9) to 1.7.

It is desirable that the optical system of the present invention has an aspherical surface in the rear group Gr in which the negative refractive power becomes stronger as the distance from the optical axis increases. Such an aspherical surface can increase the incident angle of the on-axis light ray while keeping the incident angle of the peripheral light ray small, and contributes to the correction of the spherical aberration without deteriorating the off-axis aberration.

In the optical system of the present invention, the front group Gf is composed of a first lens group Gf1 having a positive or negative refractive power and a second lens group Gf2 having a positive refractive power, and the second lens is used for focusing from infinity to close range. It is desirable that the group Gf2 and the rear group Gr move on the optical axis. At this time, the second lens group Gf2 and the rear group Gr may move together or may move with different movement amounts. With such a configuration, it is possible to reduce fluctuations in spherical aberration and astigmatism due to fluctuations in object distance.

Next, the lens configuration of the embodiment according to the optical system of the present invention will be described. In the following description, the lens configuration will be described in order from the object side to the image side.

In [plane data], the surface number is the number of the lens surface or aperture aperture 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, νd is the Abbe number with respect to the d line, and PgF is the partial dispersion ratio between the g line and the F line. BF represents back focus.

The radius of curvature ∞ (infinity) with respect to the plane or the aperture stop is entered in the area numbered (opening 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) in each shooting distance state.

[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, and 26, S is an aperture diaphragm, I is an image plane, F is an optical filter, and the alternate long and short dash line passing through the center is an optical axis.

FIG. 1 is a lens configuration diagram of an optical system according to a first embodiment of the present invention. The photographing lens of FIG. 1 is composed of a front group Gf having a positive refractive power, an aperture stop S, and a rear group Gr having a positive refractive power in order from the object side.

The front group Gf is composed of a first lens group Gf1 having a negative refractive power and a second lens group Gf2 having a positive refractive power in order from the object side.

The first lens group Gf1 includes a positive meniscus lens with a convex surface facing the object side, a negative meniscus lens with a convex surface facing the object side, a negative meniscus lens with a convex surface facing the object side, a biconcave lens and a biconvex lens in order from the object side. It is composed of a biconvex lens, which is a bonded lens component that is bonded and has a concave surface facing the object side.

The second lens group Gf2 is composed of a biconvex lens, a biconvex lens Lf1 and a biconcave lens Lf2 joined in order from the object side, and a lens component Lfb having a concave surface facing the image side.

The rear group Gr joins the biconvex lens Lr1 and the biconcave lens Lr2 in order from the object side and directs the convex surface toward the object side, the lens component Lra having a negative refractive power as a whole, and the negative meniscus lens Lr3 with the concave surface directed toward the object side. It is composed of a biconvex positive lens Lr4 and a positive meniscus lens Lr5 convex on the image side. Further, the lens surfaces on both sides of the Lr5 have a predetermined aspherical shape.

Further, when focusing from infinity to close range, the first lens group Gf1 is fixed to the image plane, and the second lens group Gf2 and the rear group Gr move toward the object with different movement amounts. The aperture stop S moves along with the rear group Gr. Further, the optical filter F is arranged between the rear group Gr and the image plane I.

Subsequently, the specification values of the photographing lens according to the first embodiment are shown below.
Numerical Example 1
Unit: mm
[Surface data]
Face number rd nd vd PgF
Physical surface ∞ (d0)
1 100.1781 5.1152 1.88300 40.80 0.57
2 263.6399 0.1500
3 96.7438 1.5000 1.43700 95.10 0.53
4 30.2768 10.2323
5 142.4961 1.5000 1.43700 95.10 0.53
6 39.8179 12.5390
7 -44.9109 1.5000 1.80518 25.46 0.62
8 43.7275 19.2720 1.69700 48.52 0.56
9 -70.7862 1.4794
10 92.7996 5.4873 1.88300 40.80 0.57
11 -1496.7015 (d11)
12 84.9103 6.3511 1.92286 20.88 0.64
13 -403.8437 2.6597
14 62.1843 12.5177 1.59282 68.63 0.54
15 -40.7651 1.5000 1.58144 40.89 0.58
16 34.4234 (d16)
(Aperture) ∞ 1.5000
18 42.5229 9.9618 1.43700 95.10 0.53
19 -26.9843 1.5000 1.64769 33.84 0.59
20 48.3757 6.4302
21 -27.6987 1.5000 1.64769 33.84 0.59
22 -89.0606 0.1500
23 79.4854 7.1914 1.59282 68.63 0.54
24 -34.9648 0.1500
25 * -1000.0176 3.1425 1.85135 40.10 0.57
26 * -62.8954 (d26)
27 ∞ 1.4500 1.52301 58.59 0.54
28 ∞ BF
Image plane ∞

[Aspherical data]
25 faces 26 faces
K 0.00000 0.00000
A4 -2.06891E-06 2.59962E-06
A6 -2.90337E-09 -2.22211E-09
A8 2.62013E-11 2.68513E-11
A10 -5.94009E-15 0.00000E + 00
A12 0.00000E + 00 0.00000E + 00

[Various data]
INF 392
Focal length 41.29 41.48
F number 1.47 1.67
Full angle of view 2ω 55.77 51.90
Image height Y 21.63 21.63
Lens total length 170.00 170.00

[Variable interval data]
INF 392
d0 ∞ 222.5038
d11 7.3395 1.3052
d16 8.5678 7.2817
d26 38.3130 45.6334
BF 1.0000 1.0000

[Lens group data]
Focal length of group origin
Gf1 1 -276.75
Gf2 12 102.97
Gr 18 66.22

FIG. 6 is a lens configuration diagram of an optical system according to a second embodiment of the present invention. The photographing lens of FIG. 6 is composed of a front group Gf having a positive refractive power, an aperture stop S, and a rear group Gr having a positive refractive power in order from the object side.

The front group Gf is composed of a first lens group Gf1 having a negative refractive power and a second lens group Gf2 having a positive refractive power in order from the object side.

The first lens group Gf1 includes a positive meniscus lens with a convex surface facing the object side, a negative meniscus lens with a convex surface facing the object side, a negative meniscus lens with a convex surface facing the object side, a biconcave lens and a biconvex lens in order from the object side. It is composed of a bonded lens component and a biconvex positive lens.

The second lens group Gf2 is composed of a biconvex positive lens, a biconvex lens Lf1 and a biconcave lens Lf2 joined in order from the object side, and a lens component Lfb having a concave surface facing the image side.

In the rear group Gr, in order from the object side, the biconvex positive lens Lr1 and the biconcave negative lens Lr2 are joined to face the convex surface toward the object side, the lens component Lra having a negative refractive power as a whole, and the concave surface toward the object side. It is composed of a negative meniscus lens Lr3, a biconvex positive lens Lr4, and a positive meniscus lens Lr5 with a convex surface facing the image side. Further, the lens surface on the object side of Lr1 and the lens surface on the object side of Lr5 have a predetermined aspherical shape.

Further, when focusing from infinity to close range, the first lens group Gf1 is fixed to the image plane, and the second lens group Gf2 and the rear group Gr move toward the object with different movement amounts. The aperture stop S moves along with the rear group Gr. Further, the optical filter F is arranged between the rear group Gr and the image plane I.

Subsequently, the specification values of the photographing lens according to the second embodiment are shown below.
Numerical Example 2
Unit: mm
[Surface data]
Face number rd nd vd PgF
Physical surface ∞ (d0)
1 115.1546 5.8945 1.88300 40.80 0.57
2 975.3495 0.1500
3 422.2284 1.5000 1.43700 95.10 0.53
4 32.2391 9.3740
5 122.5492 1.5000 1.43700 95.10 0.53
6 38.3846 13.8385
7 -44.1184 1.5000 1.78472 25.72 0.62
8 51.7057 16.4321 1.61997 63.88 0.54
9 -61.5358 0.1682
10 97.6477 6.0683 1.88300 40.80 0.57
11 -591.6935 (d11)
12 87.4079 6.9985 1.92286 20.88 0.64
13 -296.8665 6.6293
14 86.0770 11.8213 1.59282 68.63 0.54
15 -37.0626 1.5000 1.59270 35.44 0.59
16 43.4826 (d16)
(Aperture) ∞ 1.5000
18 * 53.7133 12.4441 1.49710 81.56 0.54
19 -26.21 1.5083 1.58144 40.89 0.58
20 51.676 6.3935
21 -26.2564 1.5000 1.64769 33.84 0.59
22 -100.3054 0.1500
23 72.5553 6.8628 1.59282 68.63 0.54
24 -36.6793 0.1500
25 * -299.6342 2.8782 1.85135 40.10 0.57
26 -59.8585 d (26)
27 ∞ 1.4500 1.52301 58.59 0.54
28 ∞ BF
Image plane ∞

[Aspherical data]
18 sides 25 sides
K 0.00000 0.00000
A4 1.21164E-07 -5.61743E-06
A6 1.33169E-10 -8.14410E-10
A8 -1.53784E-12 -5.21594E-12
A10 5.36290E-15 2.91778E-15
A12 0.00000E + 00 0.00000E + 00

[Various data]
INF 392
Focal length 41.07 41.46
F number 1.45 1.64
Full angle of view 2ω 56.03 51.81
Image height Y 21.63 21.63
Lens total length 170.00 170.00

[Variable interval data]
INF 392
d0 ∞ 222.5081
d11 6.1665 0.1797
d16 8.0718 6.6034
d26 36.5500 44.0052
BF 1.0000 1.0000

[Lens group data]
Focal length of group origin
Gf1 1 -197.34
Gf2 12 101.01
Gr 18 65.93
( Reference example 3)

FIG. 11 is a lens configuration diagram of the optical system of Reference Example 3 of the present invention. The photographing lens of FIG. 11 is composed of a front group Gf having a positive refractive power, an aperture stop S, and a rear group Gr having a positive refractive power in order from the object side.

The front group Gf is composed of a first lens group Gf1 having a positive refractive power as a whole and having a negative refractive power in order from the object side, and a second lens group Gf2 having a positive refractive power.

In the first lens group Gf1, in order from the object side, a positive meniscus lens having a convex surface facing the object side and a negative meniscus lens having a convex surface facing the object side are joined, and a negative lens component having the convex surface facing the object side and the object side. It is composed of a negative meniscus lens with a convex surface, a lens component obtained by joining a biconcave lens and a biconvex lens, and a biconvex positive lens.

The second lens group Gf2 is composed of a biconvex lens, a biconvex lens Lf1 and a biconcave lens Lf2 joined in order from the object side, and a lens component Lfb having a concave surface facing the image side.

In the rear group Gr, in order from the object side, the biconvex positive lens Lr1 and the biconcave negative lens Lr2 are joined and the convex surface is directed toward the object side. It is composed of a negative meniscus lens Lr3, a biconvex positive lens Lr4, and a positive meniscus lens Lr5 with a convex surface facing the image side. Further, the lens surfaces on both sides of the Lr5 have a predetermined aspherical shape.

Further, when focusing from infinity to close range, the first lens group Gf1 is fixed to the image plane, and the second lens group Gf2 and the rear group Gr move toward the object with different movement amounts. The aperture stop S moves along with the rear group Gr. Further, the optical filter F is arranged between the rear group Gr and the image plane I.

Subsequently, the specification values of the photographing lens according to Reference Example 3 are shown below.
Numerical reference example 3
Unit: mm
[Surface data]
Face number rd nd vd PgF
Physical surface ∞ (d0)
1 78.7591 5.6379 1.88300 40.80 0.57
2 177.7058 1.5000 1.49700 81.61 0.54
3 36.0637 8.2831
4 103.2502 1.5000 1.51823 58.96 0.54
5 51.2202 12.9512
6 -52.7660 1.5000 1.78472 25.72 0.62
7 56.3892 11.9542 1.59282 68.63 0.54
8 -111.2883 4.3529
9 134.5725 8.6509 1.90043 37.37 0.58
10 -118.3131 (d10)
11 78.4167 6.0793 1.92286 20.88 0.64
12 1224.2161 0.1500
13 42.9153 14.3576 1.59282 68.63 0.54
14 -54.8439 1.5000 1.58144 40.89 0.58
15 26.6838 (d15)
(Aperture) ∞ 1.5000
17 71.6768 8.3783 1.55032 75.50 0.54
18 -25.36 1.5000 1.64769 33.84 0.59
19 62.5184 5.8251
20 -26.5654 1.5000 1.69895 30.05 0.60
21 -137.5349 1.2012
22 89.264 6.5317 1.59282 68.63 0.54
23 -37.0865 0.1500
24 * -600.0000 5.4368 1.88202 37.22 0.58
25 * -56.2362 (d25)
26 ∞ 1.4500 1.52301 58.59 0.54
27 ∞ BF
Image plane ∞

[Aspherical data]
24 sides 25 sides
K 0.00000 0.00000
A4 -1.30009E-06 2.69852E-06
A6 2.42601E-09 2.42526E-09
A8 1.07857E-11 1.27803E-11
A10 -1.83824E-15 0.00000E + 00
A12 0.00000E + 00 0.00000E + 00

[Various data]
INF 392
Focal length 48.50 47.72
F number 1.45 1.71
Full angle of view 2ω 48.50 44.97
Image height Y 21.63 21.63
Lens total length 170.00 170.00

[Variable interval data]
INF 392
d0 ∞ 222.5000
d10 8.7131 1.2559
d15 11.7899 9.1854
d25 36.6069 46.6686
BF 1.0000 1.0000

[Lens group data]
Focal length of group origin
Gf1 1 -896.90
Gf2 11 113.47
Gr 17 68.87
(Example 4)

FIG. 16 is a lens configuration diagram of an optical system according to a fourth embodiment of the present invention. The photographing lens of FIG. 16 is composed of a front group Gf having a positive refractive power, an aperture stop S, and a rear group Gr having a positive refractive power in order from the object side.

The front group Gf is composed of a first lens group Gf1 having a positive refractive power and a second lens group Gf2 having a positive refractive power in order from the object side.

The first lens group Gf1 starts from a negative meniscus lens with a convex surface facing the object side, a lens component in which a biconvex lens and a biconcave lens are joined, a lens component in which a biconcave lens and a biconvex lens are joined, and a biconvex positive lens in order from the object side. It is configured.

The second lens group Gf2 has a positive refractive power, and is a positive meniscus lens whose convex surface is directed toward the object side in order from the object side. It is composed of the lens component Lfb to be directed.

The rear group Gr joins a biconvex positive lens Lr1 and a biconcave negative lens Lr2 in order from the object side, and has a lens component Lra having a negative refractive power as a whole with the convex surface facing the object side and a concave surface on the object side. It is composed of a negative meniscus lens Lr3, a biconvex positive lens Lr4, and a positive meniscus lens Lr5 with a convex surface facing the image side. Further, the lens surfaces on both sides of the Lr5 have a predetermined aspherical shape.

Further, when focusing from infinity to close range, the first lens group Gf1 is fixed to the image plane, and the second lens group Gf2, the aperture stop S, and the rear group Gr move toward the object with different movement amounts. The aperture stop S moves along with the rear group Gr. Further, the optical filter F is arranged between the rear group Gr and the image plane I.

Subsequently, the specification values of the photographing lens according to the fourth embodiment are shown below.
Numerical Example 4
Unit: mm
[Surface data]
Face number rd nd vd PgF
Physical surface ∞ (d0)
1 132.7712 1.5000 1.59270 35.44 0.59
2 35.9816 7.8270
3 102.3907 9.2006 1.77250 49.62 0.55
4 -76.4209 1.5000 1.49700 81.61 0.54
5 41.5099 12.1729
6 -45.3374 1.5000 1.80518 25.46 0.62
7 43.2101 15.2072 1.80420 46.50 0.56
8-83.7323 3.8958
9 88.1166 7.1343 1.92286 20.88 0.64
10 -182.5786 (d10)
11 84.8942 4.1496 1.90043 37.37 0.58
12 343.6632 0.6202
13 58.9249 12.0711 1.59282 68.63 0.54
14 -40.3057 1.5000 1.58144 40.89 0.58
15 35.3966 (d15)
(Aperture) ∞ 1.5000
17 50.3156 8.8789 1.43700 95.10 0.53
18 -25.7532 1.5000 1.62004 36.30 0.59
19 56.7132 6.4376
20 -24.1218 1.5000 1.75520 27.53 0.61
21 -56.3815 0.1500
22 95.9432 7.0264 1.59282 68.63 0.54
23 -32.6263 0.1500
24 * -111.9924 3.1413 1.85135 40.10 0.57
25 * -44.2632 (d25)
26 ∞ 1.4500 1.52301 58.59 0.54
27 ∞ BF
Image plane ∞

[Aspherical data]
24 sides 25 sides
K 0.00000 0.00000
A4 -4.89989E-06 1.02163E-06
A6 -3.55578E-09 -1.95928E-09
A8 4.13008E-11 3.67634E-11
A10 -1.47483E-14 0.00000E + 00
A12 0.0000E + 00 0.00000E + 00

[Various data]
INF 390
Focal length 40.75 40.11
F number 1.45 1.65
Full angle of view 2ω 56.39 53.57
Image height Y 21.63 21.63
Lens total length 167.60 167.60

[Variable interval data]
INF 390
d0 ∞ 222.5000
d10 12.6800 4.9149
d15 6.8571 7.9950
d25 37.0499 43.6771
BF 1.0000 1.0000

[Lens group data]
Focal length of group origin
Gf1 1 170.96
Gf2 11 217.52
Gr 17 70.04

FIG. 21 is a lens configuration diagram of an optical system according to a fifth embodiment of the present invention. The photographing lens of FIG. 21 is composed of a front group Gf having a positive refractive power, an aperture stop S, and a rear group Gr having a positive refractive power in order from the object side.

The front group Gf is composed of a first lens group Gf1 having a positive refractive power and a second lens group Gf2 having a positive refractive power in order from the object side.

The first lens group Gf1 is a lens component in which a negative meniscus lens having a convex surface facing the object side, a positive meniscus lens, and a negative meniscus lens having a convex surface facing the object side are joined in order from the object side, and a biconcave negative lens and a biconvex. It is composed of a biconvex positive lens, which is a lens component obtained by joining the positive lenses of. Further, the surface of the negative meniscus lens arranged on the object side of the first lens group Gf1 on the object side has a predetermined aspherical shape.

The second lens group Gf2 is composed of a positive meniscus lens having a convex surface facing the object side, a biconvex positive lens Lf1 and a biconcave negative lens Lf2 joined in order from the object side, and a lens component Lfb having a concave surface facing the image side. Has been done. Further, the surface of the positive lens Lf1 on the object side has a predetermined aspherical shape.

In the rear group Gr, in order from the object side, the biconvex positive lens Lr1 and the biconcave negative lens Lr2 are joined and the convex surface is directed toward the object side. It is composed of a negative meniscus lens Lr3, a biconvex positive lens Lr4, and a positive meniscus lens Lr5 with a convex surface facing the image side. Further, the surface of the Lr5 on the object side has a predetermined aspherical shape.

Further, when focusing from infinity to close range, the first lens group Gf1 is fixed to the image plane, and the second lens group Gf2, the aperture stop S, and the rear group Gr are integrally moved to the object side. Further, the optical filter F is arranged between the rear group Gr and the image plane I.

Subsequently, the specification values of the photographing lens according to the fifth embodiment are shown below.
Numerical Example 5
Unit: mm
[Surface data]
Face number rd nd vd PgF
Physical surface ∞ (d0)
1 * 64.2552 1.5000 1.59201 67.02 0.54
2 28.4746 7.6714
3 53.3747 6.0662 1.72916 54.67 0.55
4 248.4045 1.5000 1.43700 95.10 0.53
5 26.7947 13.7455
6 -41.3072 1.5000 1.71736 29.50 0.60
7 34.7840 14.2930 1.72916 54.67 0.55
8 -105.7513 0.5051
9 73.3762 6.5450 1.88300 40.80 0.57
10 -166.6276 (d10)
11 52.8534 6.2718 1.92286 20.88 0.64
12 -2028.2715 0.1500
13 * 187.0149 6.4787 1.55332 71.68 0.54
14 -53.6930 1.5000 1.62004 36.30 0.59
15 34.4765 6.6544
(Aperture) ∞ 1.5000
17 42.5887 9.7456 1.55032 75.50 0.54
18 -23.7752 1.5000 1.67270 32.17 0.60
19 49.1845 6.2863
20 -24.332 1.5000 1.73800 32.26 0.59
21 -82.6306 0.1500
22 63.8891 7.3518 1.59282 68.63 0.54
23 -33.3785 0.1500
24 * -449.7696 2.9789 1.88202 37.22 0.58
25 -57.3043 (d25)
26 ∞ 1.4500 1.52301 58.59 0.54
27 ∞ BF
Image plane ∞

[Aspherical data]
1 side 13 sides 24 sides
K 0.00000 0.00000 0.00000
A4 1.58447E-06 -1.44376E-08 -7.56161E-06
A6 3.24089E-10 9.61001E-11 -1.26578E-09
A8 -1.85822E-13 1.75142E-12 -8.33470E-12
A10 2.81751E-16 -4.11611E-16 8.80688E-16
A12 -1.57674E-19 0.00000E + 00 0.00000E + 00

[Various data]
INF 373
Focal length 36.05 35.77
F number 1.47 1.59
Full angle of view 2ω 62.44 59.82
Image height Y 21.63 21.63
Lens total length 150.00 150.00

[Variable interval data]
INF 373
d0 ∞ 222.5000
d10 5.4562 0.1500
d25 36.5502 41.8564
BF 1.0000 1.0000

[Lens group data]
Focal length of group origin
Gf1 1 408.26
Gf2 11 218.53
Gr 17 57.81

FIG. 26 is a lens configuration diagram of the optical system according to the sixth embodiment of the present invention. The photographing lens of FIG. 26 is composed of a front group Gf having a positive refractive power, an aperture stop S, and a rear group Gr having a positive refractive power in order from the object side.

The front group Gf is composed of a first lens group Gf1 having a positive refractive power and a second lens group Gf2 having a positive refractive power in order from the object side.

The first lens group Gf1 is a negative meniscus lens having a convex surface facing the object side, a negative meniscus lens having a convex surface facing the object side, a lens component obtained by joining a biconcave negative lens and a biconvex positive lens, in order from the object side. It consists of a biconvex positive lens. Further, the surface of the negative meniscus lens arranged on the object side of the first lens group Gf1 on the object side has a predetermined aspherical shape.

The second lens group Gf2 is composed of a positive meniscus lens having a convex surface facing the object side, a biconvex positive lens Lf1 and a biconcave negative lens Lf2 joined in order from the object side, and a lens component Lfb having a concave surface facing the image side. Has been done. Further, the surface of the positive lens Lf1 on the object side has a predetermined aspherical shape.

In the rear group Gr, in order from the object side, the biconvex positive lens Lr1 and the biconcave negative lens Lr2 are joined and the convex surface is directed toward the object side. It is composed of a negative meniscus lens Lr3, a biconvex positive lens Lr4, and a positive meniscus lens Lr5 with a convex surface facing the image side. Further, the surface of the Lr1 on the object side and the surfaces on both sides of the Lr5 have a predetermined aspherical shape.

Further, when focusing from infinity to close range, the first lens group Gf1 is fixed to the image plane, and the second lens group Gf2, the aperture stop S, and the rear group Gr are integrally moved to the object side. Further, the optical filter F is arranged between the rear group Gr and the image plane I.

Subsequently, the specification values of the photographing lens according to the sixth embodiment are shown below.
Numerical Example 6
Unit: mm
[Surface data]
Face number rd nd vd PgF
Physical surface ∞ (d0)
1 * 46.1299 3.3854 1.59201 67.02 0.54
2 22.4285 11.4787
3 91.5740 1.5000 1.43700 95.10 0.53
4 27.7803 15.0994
5 -31.2266 1.5000 1.72825 28.32 0.61
6 49.9490 10.1931 1.72916 54.67 0.55
7 -46.4217 0.1500
8 78.8421 6.0489 1.95375 32.32 0.59
9 -152.9680 (d9)
10 47.8564 6.1460 1.92286 20.88 0.64
11 -788.7197 0.1500
12 * 925.8164 4.8765 1.49710 81.56 0.54
13 -64.2443 1.5000 1.74077 27.76 0.61
14 43.3425 7.6676
(Aperture) ∞ 2.3148
16 * 70.2434 8.7280 1.49710 81.56 0.54
17 -20.983 1.5000 1.69895 30.05 0.60
18 200.000 4.6431
19 -26.2026 1.5000 1.91082 35.25 0.58
20 -55.9194 0.1500
21 55.1449 8.4521 1.59282 68.63 0.54
22 -29.8944 0.1500
23 * -128.2815 3.1153 1.88202 37.22 0.58
24 * -54.2341 (d24)
25 ∞ 1.4500 1.52301 58.59 0.54
26 ∞ BF
Image plane ∞

[Aspherical data]
1 side 12 sides 16 sides
K 0.00000 0.00000 0.00000
A4 2.77355E-06 3.28527E-06 7.35036E-07
A6 9.41383E-10 -5.08432E-10 4.34499E-09
A8 1.85798E-12 3.95977E-12 -3.95443E-12
A10 -1.60700E-15 0.00000E + 00 0.00000E + 00
A12 2.39390E-18 0.00000E + 00 0.00000E + 00

23 sides 24 sides
K 0.00000 0.00000
A4 -2.68432E-05 -1.58542E-05
A6 -2.67387E-08 -2.14489E-08
A8 -1.27059E-10 -5.59706E-11
A10 4.77755E-13 2.86893E-13
A12 0.00000E + 00 0.00000E + 00

[Various data]
INF 373
Focal length 28.84 28.59
F number 1.45 1.54
Full angle of view 2ω 74.29 72.75
Image height Y 21.63 21.63
Lens total length 150.00 150.00

[Variable interval data]
INF 373
d0 ∞ 222.5051
d9 10.7511 7.3580
d24 36.5501 39.9432
BF 1.0000 1.0000

[Lens group data]
Focal length of group origin
Gf1 1 196.57
Gf2 10 329.92
Gr 16 51.48

The values corresponding to the conditional expressions corresponding to each of the above embodiments are shown below.
Conditional expression / Example 1 2 3 *
(1) Fr / F 1.60 1.61 1.42
(2) 100 × (N2-N1) / (V2-V1) -0.34 -0.21 -0.23
(3) PgFr1- (-0.0018 × V1 + 0.6483) 0.05 0.04 0.03
(4) Vf1 68.63 68.63 68.63
(5) PgFf1- (-0.0018 × Vf1 + 0.6483) 0.02 0.02 0.02
(6) (R_fi + R_ro) / (R_fi-R_ro) -9.50 -9.50 -2.19
(7) Fr × (N2-N1) /Rac -0.52 -0.21 -0.26
(8) R_L31 / D -1.43 -1.20 -1.54
(9) Npave 1.63 1.65 1.68

Conditional expression / Example 4 5 6
(1) Fr / F 1.72 1.60 1.78
(2) 100 × (N2-N1) / (V2-V1) -0.31 -0.28 -0.39
(3) PgFr1- (-0.0018 × V1 + 0.6483) 0.05 0.02 0.04
(4) Vf1 68.63 71.68 81.56
(5) PgFf1- (-0.0018 × Vf1 + 0.6483) 0.02 0.02 0.04
(6) (R_fi + R_ro) / (R_fi-R_ro) -5.75 -9.50 -4.22
(7) Fr × (N2-N1) /Rac -0.50 -0.30 -0.50
(8) R_L31 / D -1.32 -1.28 -1.52
(9) Npave 1.63 1.68 1.66
* Indicates a reference example.

Gf Front group Gf1 First lens group Gf2 Second lens group Gr Rear group S Aperture aperture F Optical filter I Image plane

Claims (9)

From the object side, it is composed of a front group Gf having a positive refractive power, an aperture stop S, and a rear group Gr having a positive refractive power.
A lens component Lfb in which a positive lens Lf1 and a negative lens Lf2 are joined and a concave surface is directed to the image side is arranged on the most image side of the front group Gf.
In the rear group Gr, the positive lens Lr1 and the negative lens Lr2 are joined in order from the object side, the convex surface is directed toward the object side, the lens component Lra having a negative refractive power as a whole, and the negative lens Lr3 with the concave surface directed toward the object side. It has a positive lens Lr4 and
A shooting lens characterized by satisfying the following conditional expression.
(1) 1.6 ≤ Fr / F <2.5
(2) -0.7 <100 x (N2-N1) / (V2-V1) <-0.05
Fr: Focal length of the rear group Gr: Focal length of the whole system N1: Refractive index of Lr1 N2: Refractive index of Lr2 V1: Abbe number of Lr1 V2: Abbe number of Lr2 The photographing lens according to claim 1, wherein the Lr1 satisfies the following conditional expression.
(3) PgFr1- (-0.0018 × V1 + 0.6483)> 0
PgFr1: Partial dispersion ratio of the positive lens Lr1 V1: Abbe number of the Lr1
The photographing lens according to claim 1 or 2, wherein the positive lens Lf1 constituting the lens component Lfb arranged on the most image side of the front group Gf satisfies the following conditional expression.
(4) Vf1> 50
(5) PgFf1- (-0.0018 x Vf1 + 0.6483)> 0
Vf1: Abbe number of the positive lens Lf1 PgFf1: Partial dispersion ratio of the positive lens Lf1
The photographing lens according to any one of claims 1 to 3, wherein the photographing lens satisfies the following conditional expression.
(6) -15 <(R_fi + R_ro) / (R_fi-R_ro) <-1
R_fi: Radius of curvature of the most image-side surface of the front group Gf R_ro: Radius of curvature of the most object-side surface of the rear group Gr
The photographing lens according to any one of claims 1 to 4, wherein the photographing lens satisfies the following conditional expression.
(7) -0.9 <Fr × (N2-N1) /Rac <-0.05
Fr: Focal length of the rear group Gr: Refractive index of Lr1 N2: Refractive index of Lr2 Rac: Radius of curvature of the junction surface of the lens component Lra
The photographing lens according to any one of claims 1 to 5, wherein the photographing lens satisfies the following conditional expression.
(8) -1.8 <R_L31 / D <-1.0
R_Lr31: Radius of curvature D on the object side of the negative lens Lr3: Distance on the optical axis from the aperture stop S to the surface of the negative lens Lr3 on the object side.
The photographing lens according to any one of claims 1 to 6, wherein the photographing lens satisfies the following conditional expression.
(9) Npave <1.75
Npave: Mean value of the refractive index of the positive lens included in the rear group Gr
The photographing lens according to any one of claims 1 to 7, wherein the rear group Gr has at least one aspherical surface whose negative refractive power becomes stronger as the distance from the optical axis increases.
The front group Gf is composed of a first lens group Gf1 having a positive or negative refractive power and a second lens group Gf2 having a positive refractive power in order from the object side.
A claim characterized in that the first lens group Gf1 is fixed to an image plane during focusing from infinity to close proximity, and the second lens group Gf2 and the rear group Gr move toward an object on the optical axis. The photographing lens according to any one of 1 to 8.

Images