JP7178796B2 - INNER FOCUS IMAGING LENS AND IMAGING DEVICE - Google Patents

Description

The present invention is an inner-focus imaging lens that is compact as a whole and that satisfactorily corrects various aberrations from infinity to the closest object.It is possible to reduce the load on the focus drive system by reducing the weight of the lens system of the focus group in particular. The present invention relates to an inner-focus imaging lens and an imaging apparatus equipped with such an inner-focus imaging lens.

2. Description of the Related Art In recent years, particularly in photographing using a digital camera, photographing devices capable of photographing both still images and moving images with a single photographing device have become widespread. A photographing lens required for such a photographing apparatus is required to have high-speed focusing because images are always recorded not only when photographing a still image but also when photographing a moving image.
In particular, in a photographing device having a contrast detection autofocus mechanism, the lens group moves minutely to determine whether the focus lens group should move along the optical axis in the direction of the object or in the direction of image formation for focusing. , a so-called wobbling lens group. Since both the focus lens group and the wobbling lens group operate to change the focal position along the optical axis, it is desirable that the focus lens group also has the function of the wobbling lens group. Due to the required movement, it is even more desirable to reduce the weight of the focus lens group.

In recent years, interchangeable-lens cameras are often equipped with a movie shooting function, and there is an increasing demand for an anti-shake function to prevent image deterioration due to camera shake during movie shooting.

Patent No. 5714925 JP 2016-118770

Regarding conventional inner focus lenses, patent document 1 discloses an inner focus lens that is compact, has a wide angle, and has excellent imaging performance, as well as achieving sufficient weight reduction of the focus lens group. ing.

In the inner focus type lens disclosed in Patent Document 1, the focus lens is made into one lens group, and the focus lens group is composed of one negative lens. Therefore, it was possible to reduce the load on the focus lens group driving system. However, in order to increase the close-up magnification, it is theoretically necessary to increase the amount of movement of the focus lens group or increase the lateral magnification.
When the movement amount of the focus lens group is increased in the inner focus type lens disclosed in Patent Document 1, spherical aberration, curvature of field, longitudinal chromatic aberration, etc. increase, making it difficult to correct various aberrations.
In addition, even when the lateral magnification of the focus lens group is increased in the inner focus type lens disclosed in Patent Document 1, it becomes difficult for each lens group to maintain an appropriate power, resulting in aberrations during focusing from infinity to close distance. In order to avoid this, a large number of lenses are required, which hinders the reduction of the load on the focus lens group drive system and miniaturization.

The inner focus lens disclosed in Patent Document 1 also does not have a vibration reduction mechanism and cannot meet the requirement for vibration reduction.

Patent Document 2 discloses a lens system, an interchangeable lens device, and a camera system which are conventional inner focus lenses and in which aberrations are suppressed. For example, Numerical Example 5 of Patent Document 2 has a positive-positive-negative positive-negative structure, and focusing from an infinity object focus state to a close object focus state is performed with the second lens group and the fourth lens group on the optical axis. to the object side.

However, in Numerical Example 5, the power balance between the second lens group and the fourth lens group, which are focus lens groups, is poor, and the lateral magnification of the fourth lens group is too high. requires an increase in the number of lenses in the fourth lens group, which increases the load on the focus lens group drive system, and hinders wobbling support required for moving image shooting. In addition, there is a problem that it does not have a vibration reduction mechanism and cannot satisfy the demand for vibration reduction correction.

(Purpose of Invention)
The present invention has been made in view of the above-mentioned problems of the conventional inner focus type imaging lens, and is compact as a whole and satisfactorily corrects various aberrations from focusing at infinity to focusing at the closest distance. An object of the present invention is to provide an inner focus type imaging lens and an imaging device having the same.

The present invention comprises a first focus lens group having positive refractive power, and a second focus lens group having positive refractive power arranged closer to the image side than the first focus lens group, and When focusing on a short-distance object, the first focus lens group moves toward the object side, and the second focus lens group moves toward the object side by a movement amount different from that of the first focus lens group. It is a focus type imaging lens.
The present invention is also an image pickup apparatus comprising the inner focus type image pickup lens and an image pickup device arranged on the image plane of the inner focus type image pickup lens.

According to the present invention, there is provided an inner focus type imaging lens which is compact as a whole and which satisfactorily corrects various aberrations, particularly from focusing at infinity to focusing at the closest distance, and in particular, a focus lens by reducing the weight of the lens system of the focus lens group. It is possible to provide an inner focus type imaging lens capable of reducing the load on a group drive system and an imaging apparatus having the same.

1 is a lens configuration diagram of Example 1 of an inner focus imaging lens of the present invention. FIG. FIG. 2 is various aberration diagrams in the infinity focused state of Example 1 of the inner focus type imaging lens of the present invention. FIG. 2 is various aberration diagrams in the infinity focused state of Example 1 of the inner focus type imaging lens of the present invention. FIG. 4 is a graph showing various aberrations in the closest focus state of Example 1 of the inner focus imaging lens of the present invention. FIG. 4 is a graph showing various aberrations in the closest focus state of Example 1 of the inner focus imaging lens of the present invention. FIG. 5 is a lens configuration diagram of Example 2 of the inner focus imaging lens of the present invention. FIG. 10 is a diagram of various aberrations in the infinity focused state of Example 2 of the inner focus imaging lens of the present invention; FIG. 10 is a diagram of various aberrations in the infinity focused state of Example 2 of the inner focus imaging lens of the present invention; FIG. 10 is a diagram of various aberrations in the closest focus state of Example 2 of the inner focus imaging lens of the present invention; FIG. 10 is a diagram of various aberrations in the closest focus state of Example 2 of the inner focus imaging lens of the present invention; FIG. 10 is a lens configuration diagram of Example 3 of the inner focus imaging lens of the present invention; FIG. 10 is a diagram of various aberrations in the infinity focused state of Example 3 of the inner focus imaging lens of the present invention; FIG. 10 is a diagram of various aberrations in the infinity focused state of Example 3 of the inner focus imaging lens of the present invention; FIG. 10 is a diagram of various aberrations in the closest focus state of Example 3 of the inner focus imaging lens of the present invention; FIG. 10 is a diagram of various aberrations in the closest focus state of Example 3 of the inner focus imaging lens of the present invention; FIG. 11 is a lens configuration diagram of Example 4 of the inner focus imaging lens of the present invention; FIG. 10 is a diagram of various aberrations in the infinity focused state of Example 4 of the inner focus type imaging lens of the present invention; FIG. 10 is a diagram of various aberrations in the infinity focused state of Example 4 of the inner focus type imaging lens of the present invention; FIG. 10 is a diagram of various aberrations in the closest focus state of Example 4 of the inner focus imaging lens of the present invention; FIG. 10 is a diagram of various aberrations in the closest focus state of Example 4 of the inner focus imaging lens of the present invention; FIG. 11 is a lens configuration diagram of Example 5 of the inner focus imaging lens of the present invention. FIG. 11 is a diagram of various aberrations in the infinity focused state of Example 5 of the inner focus imaging lens of the present invention; FIG. 11 is a diagram of various aberrations in the infinity focused state of Example 5 of the inner focus imaging lens of the present invention; FIG. 10 is a diagram of various aberrations in the closest focus state of Example 5 of the inner focus imaging lens of the present invention. FIG. 10 is a diagram of various aberrations in the closest focus state of Example 5 of the inner focus imaging lens of the present invention. FIG. 11 is a lens configuration diagram of Example 6 of the inner focus imaging lens of the present invention. FIG. 10 is a diagram of various aberrations in the infinity focused state of Example 6 of the inner focus imaging lens of the present invention; FIG. 10 is a diagram of various aberrations in the infinity focused state of Example 6 of the inner focus imaging lens of the present invention; FIG. 10 is a diagram of various aberrations in the closest focused state of Example 6 of the inner focus imaging lens of the present invention; FIG. 10 is a diagram of various aberrations in the closest focused state of Example 6 of the inner focus imaging lens of the present invention; FIG. 11 is a lens configuration diagram of Example 7 of the inner focus imaging lens of the present invention. FIG. 10 is a diagram of various aberrations in an infinitely focused state of Example 7 of the inner focus type imaging lens of the present invention; FIG. 10 is a diagram of various aberrations in an infinitely focused state of Example 7 of the inner focus type imaging lens of the present invention; FIG. 12 is various aberration diagrams in the closest focus state of Example 7 of the inner focus type imaging lens of the present invention. FIG. 12 is various aberration diagrams in the closest focus state of Example 7 of the inner focus type imaging lens of the present invention. FIG. 12 is a configuration diagram of an eighth embodiment of the imaging device of the present invention;

Embodiments of the present invention will be described below.
(First embodiment)
A first embodiment of the present invention comprises a first focus lens group having positive refractive power, and a second focus lens group having positive refractive power disposed closer to the image side than the first focus lens group. and, when focusing from an object at infinity to a short distance object, the first focus lens group moves toward the object side, and the second focus lens group moves toward the object side by a movement amount different from that of the first focus lens group. This is an inner focus imaging lens characterized by

In the first embodiment of the present invention, by arranging two focus lens groups, it is possible to increase the photographing magnification with a small amount of movement, and the weight of the focus lens group is reduced to reduce the weight of the focus lens group drive system. It becomes possible to reduce the load. Furthermore, since the extension amount is reduced, aberration fluctuations can be suppressed, and various aberrations can be satisfactorily corrected from focusing at infinity to focusing at the closest distance.

(Second embodiment)
A second embodiment of the present invention is an inner focus imaging lens characterized by satisfying the following conditional expression (1) in the first embodiment.
(1) 0.3 ≤ fo1 / fo2 ≤ 3.3
where fo1 is the focal length of the first focus lens group
fo2: focal length of the second focus lens group

Conditional expression (1) indicates the ratio of the focal lengths of the first focus lens group and the second focus lens group. By satisfying conditional expression (1), it is possible to make the amount of movement of each focus lens group appropriate, to make the optical system compact, and to correct aberrations with a small number of lenses.

If the lower limit of conditional expression (1) is not reached, the power of the second focus lens group is weak, resulting in a low lateral magnification. Otherwise, the power of the first focus lens group is too strong, resulting in excess spherical aberration and under curvature of field, making it difficult to correct aberrations with a small number of lenses and increasing the load on the focus drive system.
On the other hand, when the upper limit of conditional expression (1) is exceeded, the lateral magnification is low because the power of the first focus lens group is weak. Either the design becomes difficult, or the power of the second focus lens group becomes too strong, and both spherical aberration and curvature of field tend to be under-corrected. Become.

Further, if the conditional expression (1) satisfies the following range, a more favorable effect can be expected. At this time, even if either the upper limit or the lower limit of the range shown below is satisfied, favorable effects can be expected.
Preferably (1)' 0.6 ≤ fo1 / fo2 ≤ 3.0
More preferably (1)'' 0.9 ≤ fo1 / fo2 ≤ 2.7
More preferably (1)''' 1.2 ≤ fo1 / fo2 ≤ 2.4

(Third embodiment)
3rd Embodiment is an inner It is a focus type imaging lens.

By disposing the negative lens group between the first focus lens group and the second focus lens group, it becomes possible to increase the lateral magnification of at least one of the first focus lens group and the second focus lens group. , the amount of movement of the first focus lens group and the second focus lens group (focus lens group with increased lateral magnification) required for focusing can be reduced, and a compact optical system can be designed.

At this time, having a lens group having a negative refractive power between the first focus lens group and the second focus lens group means that the lens group is arranged between the first focus lens group and the second focus lens group. indicates that the composite focal length of all lenses that are used is negative. Preferably, the lens group with negative refractive power is fixed to the optical axis during focusing.

By disposing a negative lens group between the first focus lens group and the second focus lens group and satisfying the conditional expression (1) described above, the lateral magnification of the first focus lens group and the second focus lens group is can be made appropriate, the amount of extension can be made appropriate, and the optical system can be made more compact.

(Fourth embodiment)
A fourth embodiment of the present invention is one of the first to third embodiments, characterized in that a lens group having negative refractive power is provided closer to the image side than the second focus lens group. It is an inner focus type imaging lens.

By having the negative lens group behind the second focus lens group, the peripheral luminous flux passing through the second focus lens group approaches the optical axis, making it possible to reduce the diameter and weight of the second focus lens group. It is possible to design an optical system that can meet the demands of high-speed focusing and wobbling operations.

(Fifth embodiment)
A fifth embodiment of the present invention is an inner focus type lens system according to one of the first to fourth embodiments, wherein the second focus lens group is composed of one lens component. It is an imaging lens.
Here, the single lens component refers to a lens such as a single lens, a cemented lens, or a compound aspherical lens that does not include an air layer between the surface closest to the object and the surface closest to the image.

By constructing the second focus lens group with a single lens component, it is possible to reduce the weight of the optical system and meet the demands for high-speed focusing and wobbling operations.

(Sixth embodiment)
A sixth embodiment of the present invention is one of the first to fifth embodiments, and is arranged between the first focus lens group and the second focus lens group in a direction perpendicular to the optical axis. This is an inner focus imaging lens characterized by having a vibration reduction lens group that corrects camera shake by moving.

Since the central luminous flux and the peripheral luminous flux converge between the first focus lens group and the second focus lens group, it is possible to reduce the size and weight of the anti-vibration lens group. In addition, since the optical path difference between the infinity object focus state and the close object focus state is small, it becomes easy to improve the resolution performance during image stabilization.

(Seventh embodiment)
The seventh embodiment of the present invention is an inner focus imaging lens characterized by satisfying the following conditional expression (2) in the sixth embodiment.
(2) 0.05 ≤ |(1-βvc)×βr| ≤ 1.9
where βvc is the lateral magnification of the anti-vibration lens group when focused at infinity;
βr: Composite lateral magnification of lenses placed on the image side of the anti-vibration lens group when focusing on infinity

Conditional expression (2) is a conditional expression that defines the ratio of image shift with respect to the amount of movement of the anti-vibration lens group.
If the upper limit of conditional expression (2) is exceeded, even if the anti-vibration lens group moves minutely, the image will shift significantly, so high-precision control is required. In addition, the power of the anti-vibration lens group is large, and spherical aberration tends to be excessive, making it difficult to achieve high resolution performance.
If the lower limit of conditional expression (2) is exceeded, the amount of movement of the anti-vibration lens group required to shift the image by a predetermined amount becomes large, so the anti-vibration drive system becomes large and the size of the lens barrel is reduced. hindrance to

Further, if conditional expression (2) satisfies the following range, a more favorable effect can be expected. At this time, even if either the upper limit or the lower limit of the range shown below is satisfied, favorable effects can be expected.
Preferably, (2)' 0.10 ≤ |(1-βvc) × βr| ≤ 1.6
More preferably, (2)'' 0.15 ≤ |(1-βvc) × βr| ≤ 1.3
More preferably, (2)''' 0.20 ≤ |(1-βvc) × βr| ≤ 1.0

(Eighth embodiment)
An eighth embodiment of the present invention is an inner focus imaging lens characterized in that, in the sixth or seventh embodiment, the anti-vibration lens system is composed of one lens component.

If the anti-vibration lens group is composed of a plurality of lenses, it becomes difficult to reduce the weight, and the size of the anti-vibration drive system becomes large, which hinders reduction in the size of the lens barrel.

(Ninth embodiment)
A ninth embodiment of the present invention is one of the first to eighth embodiments, and has at least one lens element having a positive power on the object side of the first focus lens group. An inner focus type imaging lens characterized by satisfying conditional expressions (3) and (4).
(3) G1dPgF ≤ 0.0282
(4) G1vd ≤ 46.0
where, G1dPgF: lens element with positive power on the object side of the first focus lens group
Anomalous dispersion of g-line and F-line
G1vd: Lens element with positive power on the object side of the first focus lens group
Abbe number at the d-line

When conditional expressions (3) and (4) are satisfied, it is possible to suppress fluctuations in axial chromatic aberration and lateral chromatic aberration from infinity to close range.

(Tenth embodiment)
A tenth embodiment of the present invention is one of the first to ninth embodiments, wherein at least one lens element having negative power is provided in the first focus lens group, and the following conditions are satisfied: An inner focus imaging lens characterized by satisfying formulas (5) and (6).
(5) G2dPgF ≥ 0.0007
(6) G2vd ≤ 45.0
where, G2dPgF: G-line and F-line of the lens element with negative power in the first focus lens group
anomalous dispersion
G2vd: at the d-line of a lens element with negative power in the first focus lens group
Abbe number

When conditional expressions (5) and (6) are satisfied, it is possible to suppress fluctuations in axial chromatic aberration and lateral chromatic aberration from infinity to close range.

(Eleventh embodiment)
An eleventh embodiment of the present invention is one of the first to tenth embodiments, wherein an aperture stop is arranged between the first focus lens group and the second focus lens group. This is an inner focus imaging lens characterized by

Arranging the focus lens group across the aperture stop facilitates the arrangement of the focus driving system and the control of vignetting of the upper and lower rays of the peripheral luminous flux.

(12th embodiment)
A twelfth embodiment of the present invention is characterized in that it comprises one of the inner focus imaging lenses of Embodiments 1 to 11, and an imaging element arranged on the image plane of the inner focusing imaging lens. It is an imaging device.

The imaging device is compact as a whole, and takes advantage of the features of an inner-focusing imaging lens that effectively corrects various aberrations, especially from focusing at infinity to focusing at the closest distance. can do.

(Example)
Embodiments 1 to 8 of the inner focus imaging lens of the present invention will be described below with reference to the accompanying drawings.
In the optical specification table of the example of the inner focus type imaging lens, No. is the surface number, and the surface number indicates the order of the surface from the object side to the image plane side. R is the radius of curvature of each lens surface (mm), D is the lens thickness and air gap (mm), Nd and ABV are the refractive index and Abbe number at the wavelength of the d-line (λ=587.6 nm). The sign of the radius of curvature is positive when the convex surface faces the object side.
F is the focal length (mm) of the entire inner focus imaging lens system, Fno is the F number, and W is the half angle of view (°).

A surface numbered with ASPH is an aspherical surface. The aspherical shape has the vertex of the surface as the origin, the coordinate perpendicular to the optical axis is H, the displacement in the direction of the optical axis at H is X(H), the paraxial radius of curvature is R, the conic coefficient is ε, and the second-order Assuming an aspherical coefficient A, a 4th-order aspherical coefficient B, a 6th-order aspherical coefficient C, an 8th-order aspherical coefficient D, and a 10th-order aspherical coefficient E, the following equation (1) is obtained.

The sign of the surface shape and refractive power is considered in the paraxial region when an aspherical surface is included.

1, 4, 7, 10, 13, 16, and 19, which show the lens configuration diagrams of the embodiments, show the infinity in-focus state and the closest distance in-focus state. Of the aberration diagrams, FIGS. 2, 5, 8, 11, 14, 17, and 20 show various longitudinal aberrations (A) and lateral aberrations (B) in the infinity focused state. Of the aberration diagrams, FIGS. 3, 6, 9, 12, 15, 18, and 21 show various longitudinal aberrations (A) and lateral aberrations (B) in the state of focus at the shortest distance. Each longitudinal aberration diagram shows spherical aberration (mm), astigmatism (mm), and distortion (%) in order from the left of the drawing. In the spherical aberration diagrams, the vertical axis represents the ratio to the maximum F-number, the solid line represents the d-line (587.5618 nm), the dashed line the C-line (656.2725 nm), and the long dashed line the F-line (486.1327 nm). In the astigmatism diagrams, the vertical axis represents the image height (IMG HT), the solid line represents the sagittal direction (S), and the four-dot chain line represents the meridional direction (T). In the distortion diagrams, the vertical axis represents the image height (IMG HT). In each lateral aberration diagram, the left side shows the lateral aberration in the tangential direction and the right side shows the lateral aberration in the sagittal direction for each image height (half angle of view) from the top. In these lateral aberration diagrams, the solid line represents the d-line (587.5618 nm), the dashed line represents the C-line (656.2725 nm), and the long dashed line represents the F-line (486.1327 nm).

(Example 1)
As shown in FIG. 1, the inner focus imaging lens of Example 1 includes a positive first lens group L1, a positive second lens group L2, a negative third lens group L3, a positive fourth lens group L4, It is the configuration of the negative fifth lens L5, the second lens group L2 is the first focus lens group, and the fourth lens group L4 is the second focus lens group.

An optical specification table of the inner focus imaging lens of Example 1 is shown below.
No. RD Nd ABV
1ASPH -1212.5063 1.4000 1.49845 81.61
2ASPH 29.0985 12.4057
3 170.9861 4.9865 1.94136 21.13
4 -68.1355 6.1277
5 -35.9780 1.2000 1.85505 23.78
6 -454.1711 2.5504
7ASPH 25.9693 8.1222 1.59412 67.02
8ASPH -33.7218 2.7571
9STOP 0.0000 0.2000
10 104.2271 1.0224 1.80655 25.30
11 23.8723 15.5621
12ASPH 43.8452 5.6989 1.49856 81.56
13ASPH -31.2197 0.2000
14 33.3772 5.9035 1.86290 24.80
15 266.4530 1.2815 1.65965 33.72
16 19.5017 12.2639
17 -20.7323 1.2000 1.61599 38.71
18 -33.4231 17.5658

infinity short range
F 41.1947 36.1160
Fno 2.0834 2.3759
W 27.4433 23.7380
D(0) INF 134.5124
D(4) 6.1277 2.6108
D(8) 2.7571 6.2740
D(11) 15.5621 11.2121
D(13) 0.2000 4.5500

The aspheric coefficients of Example 1 are shown below.
No. ε *4 *6 *8 *10
1 1.00000E+00 6.40958E-06 -2.02463E-08 3.45386E-11 -2.75776E-14
2 1.00000E+00 5.65334E-06 -1.43670E-08 1.97422E-11 -2.41721E-14
7 1.00000E+00 -1.19932E-05 -3.89527E-09 -2.76725E-11 1.24792E-13
8 1.00000E+00 1.26852E-05 -1.31319E-08 1.35488E-11 8.33317E-14
12 1.00000E+00 -1.84977E-06 -5.69701E-09 -3.09555E-11 6.56866E-14
13 1.96612E+00 6.29488E-06 4.80463E-11 2.02382E-11 -5.09673E-14

(Example 2)
As shown in FIG. 3, the inner focus imaging lens of Example 2 includes a positive first lens group L1, a positive second lens group L2, a negative third lens group L3, a positive fourth lens group L4, The configuration of the negative fifth lens group L5 is such that the second lens group L2 is the first focus lens group and the fourth lens group L4 is the second focus lens group.

An optical specification table of the inner focus imaging lens of Example 2 is shown below.
No. RD Nd ABV
1 93.7186 1.2100 1.55350 51.76
2 33.5533 8.1771 1.88621 40.14
3 1027.4025 7.2701
4 -65.7611 1.2000 1.68988 31.22
5 288.6738 0.2000
6ASPH 35.9503 7.9664 1.59489 68.62
7ASPH -62.3459 0.2000
8 123.8312 1.2000 1.89262 29.84
9 26.7206 6.7003
10STOP 0.0000 24.0963
11ASPH 90.0851 3.2672 1.59489 68.62
12ASPH -50.2927 2.7146
13 352.7908 4.3549 1.86290 24.80
14 -34.8987 3.2867 1.67017 32.78
15 99.3779 7.6526
16 -32.2053 1.2000 1.80969 42.90
17 -189.6140 19.7532

infinity short range
F87.3068 60.3001
Fno 2.0602 2.5154
W 13.6158 11.7595
D(0) INF 292.4777
D(3) 7.2701 3.2701
D(7) 0.2000 4.2000
D(10) 24.0963 15.4823
D(12) 2.7146 11.3286

The aspheric coefficients of Example 2 are shown below.
No. ε *4 *6 *8 *10
6 1.00000E+00 -3.62033E-06 -2.21401E-09 -7.67439E-12 8.86764E-15
7 1.00000E+00 4.66764E-06 -6.48288E-09 3.21758E-12 3.10470E-15
11 1.00000E+00 3.11699E-07 5.90701E-09 -5.58276E-11 -1.91998E-14
12 -0.36293E+00 -1.21240E-06 7.25732E-09 -5.91160E-11 -4.13513E-14

(Example 3)
As shown in FIG. 7, the inner focus imaging lens of Example 3 includes a positive first lens group L1, a positive second lens group L2, a negative third lens group L3, a positive fourth lens group L4, It is the configuration of the negative fifth lens group L5, the second lens group L2 is the first focus lens group, and the fourth lens L4 is the second focus lens group.

An optical specification table of the inner focus imaging lens of Example 3 is shown below.
No. RD Nd ABV
1ASPH 144.2896 1.2000 1.59035 69.06
2ASPH 18.0423 26.6523
3 39.0915 3.6647 1.90539 32.50
4 -88.7922 4.9746
5 -28.5745 1.2000 1.85505 23.78
6 0.0000 0.2000
7ASPH 39.9090 4.9136 1.72086 49.84
8ASPH -24.5222 1.5000
9STOP 0.0000 1.8144
10 59.0991 1.2000 1.82660 24.63
11 17.3219 10.1939
12ASPH 36.5683 4.6860 1.67031 55.23
13ASPH -21.6467 0.2000
14 -29.5345 1.2000 1.70804 29.98
15 -39.9753 0.2000
16 -167.1765 1.2168 1.88621 40.14
17 -162.2011 0.2000
18 609.1983 1.2000 1.59745 68.00
19 23.9583 24.0298

infinity short range
F25.5053 22.5703
Fno 2.0640 2.2011
W 40.7679 38.9042
D(0) INF 69.0527
D(4) 4.9746 3.2034
D(8) 1.5000 3.2712
D(11) 10.1939 8.6007
D(13) 0.2000 1.7932

The aspheric coefficients of Example 3 are shown below.
No. ε *4 *6 *8 *10
1 1.00000E+00 1.23969E-06 -7.26264E-09 1.55979E-11 -3.34862E-15
2 1.00000E+00 -2.98346E-06 -1.50521E-08 -5.70384E-11 -3.82983E-14
7 1.00000E+00 -2.00525E-05 -1.59477E-08 -8.50223E-12 -3.61332E-14
8 1.00000E+00 1.69432E-05 -5.91383E-08 2.02637E-10 -5.76224E-13
12 1.00000E+00 -8.31099E-06 -1.90220E-08 8.57290E-12 5.70173E-13
13 -0.42671E-01 1.24067E-05 -4.59324E-09 -4.46177E-10 2.53286E-12

(Example 4)
As shown in FIG. 10, the inner focus imaging lens of Example 4 includes a negative first lens group L1, a positive second lens group L2, a negative third lens group L3, a positive fourth lens group L4, The configuration of the negative fifth lens group L5 is such that the second lens group L2 is the first focus lens group and the fourth lens group L4 is the second focus lens group.

An optical specification table of the inner focus imaging lens of Example 4 is shown below.
(Example 4)
No. RD Nd ABV
1ASPH -78.2652 1.3957 1.49853 81.63
2ASPH 33.3626 3.4702
3 243.5409 3.8575 1.94531 20.32
4 -68.8567 9.7200
5 -29.5735 1.2026 1.87533 22.25
6 -65.2816 7.4205
7ASPH 23.9635 7.9275 1.59412 67.02
8ASPH -36.8715 1.5000
9STOP 0.0000 1.8103
10 91.4476 0.9970 1.85505 23.78
11 23.6155 16.3202
12ASPH 41.5111 5.9874 1.49856 81.56
13ASPH -29.9802 0.1985
14 36.7723 7.4493 1.86290 24.80
15 -428.8345 1.1097 1.72037 39.19
16 20.1231 10.4727
17 -18.5250 1.2007 1.58580 43.84
18 -27.4392 16.9226

infinity short range
F 40.3257 35.5993
Fno 2.0601 2.3208
W 28.0112 24.2389
D(0) INF 132.3661
D(4) 9.7200 6.7748
D(8) 1.5000 4.4462
D(11) 16.3202 11.9698
D(13) 0.1985 4.5464

The aspheric coefficients of Example 4 are shown below.
No. ε *4 *6 *8 *10
1 1.00000E+00 6.84115E-06 -1.73113E-08 3.30311E-11 -3.74126E-14
2 1.00000E+00 -5.25764E-07 -1.16342E-08 9.34315E-12 -3.25672E-14
7 1.00000E+00 -1.37129E-05 6.01825E-10 -5.47753E-11 2.20626E-13
8 1.00000E+00 1.50797E-05 -1.64311E-08 2.51506E-11 1.16154E-13
12 1.00000E+00 -2.68692E-06 -1.19155E-08 1.22634E-11 -5.54621E-14
13 1.88983E+00 7.31224E-06 1.09594E-09 1.45533E-11 -3.19242E-14

(Example 5)
As shown in FIG. 13, the inner focus imaging lens of Example 5 includes a positive first lens group L1, a positive second lens group L2, a negative third lens group L3, and a positive fourth lens group L4. , the negative fifth lens group L5, the second lens group L2 is the first focus lens group, and the fourth lens L4 is the second focus lens group.

The optical specification table of the inner focus imaging lens of Example 5 is shown below.
(Example 5)
No. RD Nd ABV
1ASPH -144.9792 1.4001 1.50841 79.78
2ASPH 29.9487 8.2836
3 -322.0749 3.5524 1.94256 20.87
4 -52.1927 7.6513
5 -23.7315 1.2001 1.87452 22.30
6 -42.7383 5.1398
7ASPH 26.2145 8.0508 1.59412 67.02
8ASPH -31.4199 1.5020
9STOP 0.0000 1.6805
10 76.9449 0.9998 1.68894 31.29
11 20.9447 16.2467
12 47.8142 7.8130 1.53998 74.89
13 -17.4544 1.1998 1.72763 29.87
14ASPH -27.4945 0.2002
15 53.7381 6.2365 1.86290 24.80
16 -28.5797 1.1100 1.69410 33.47
17 26.1070 10.1769
18 -15.4296 1.1995 1.85869 34.28
19 -22.0548 15.9633

infinity short range
F 37.7214 33.0633
Fno 2.0600 2.2720
W 30.1474 26.7569
D(0) INF 120.6865
D(4) 7.6513 4.9677
D(8) 1.5020 4.1858
D(11) 16.2467 11.8982
D(14) 0.2002 4.5497

The aspheric coefficients of Example 5 are shown below.
No. ε *4 *6 *8 *10
1 1.00000E+00 7.73911E-06 -2.42113E-08 3.11207E-11 -3.05238E-14
2 1.00000E+00 1.72533E-06 -1.71241E-08 -1.98236E-11 -4.69372E-14
7 1.00000E+00 -1.29551E-05 2.25819E-09 -3.91687E-11 1.89476E-13
8 1.00000E+00 1.44505E-05 -8.67265E-09 9.66543E-12 1.18841E-13
14 1.93852E+00 6.62353E-06 2.55413E-09 3.22498E-11 1.52721E-14

(Example 6)
As shown in FIG. 16, the inner focus imaging lens of Example 6 includes a positive first lens group L1, a positive second lens group L2, a negative third lens group L3, and a positive fourth lens group L4. , the negative fifth lens group L5, the second lens group L2 is the first focus lens group, and the fourth lens L4 is the second focus lens group. In the third lens group L3 of the inner focus imaging lens of Example 6, the negative lens arranged on the image side is a vibration reduction lens group.

An optical specification table of the inner focus imaging lens of Example 6 is shown below.
(Example 6)
No. RD Nd ABV
1ASPH -43.5266 1.2000 1.63362 36.44
2ASPH 56.3816 11.7252
3 67.1842 4.6770 2.06011 26.94
4 -97.6864 6.8650
5 -33.9476 0.9000 1.74707 27.76
6 143.8662 4.0940
7ASPH 30.5293 8.4267 1.59412 67.02
8ASPH -28.0899 9.0426
9STOP 0.0000 1.5129
10 54.7950 1.2000 1.75012 27.63
11 24.2625 3.1410
12ASPH 77.3167 1.2000 1.49856 81.56
13ASPH 47.6594 6.7361
14ASPH 93.9603 3.8390 1.49856 81.56
15ASPH -23.9153 1.5091
16 -26.1396 2.0613 1.88621 40.14
17 -21.1309 1.2100 1.64591 35.08
18 -34.3681 8.2055
19 79.9335 1.2000 1.49845 81.61
20 32.5952 21.7017

infinity short range
F 41.2014 36.2004
Fno 2.0600 2.3254
W 28.1265 24.5238
D(0) INF 130.4830
D(4) 6.8650 3.0748
D(8) 9.0426 12.8328
D(13) 6.7361 2.5251
D(15) 1.5091 5.7201

The aspheric coefficients of Example 6 are shown below.
No. ε *4 *6 *8 *10
1 1.00000E+00 1.35021E-05 -2.28598E-08 2.90367E-11 -1.91937E-14
2 1.00000E+00 6.77610E-06 -1.09467E-08 7.55415E-12 -2.98774E-15
7 1.00000E+00 -1.60670E-05 5.27756E-09 -1.50323E-11 1.97303E-14
8 1.00000E+00 1.22746E-05 -1.19400E-08 2.28792E-11 -7.10720E-15
12 1.00000E+00 -6.37003E-06 -5.05953E-08 5.55206E-10 -1.01982E-12
13 1.00000E+00 -8.25959E-06 -2.72239E-08 3.11555E-10 -1.42452E-13
14 1.00000E+00 1.16536E-07 4.26346E-08 -4.32069E-10 1.37300E-12
15 1.00000E+00 7.37942E-06 4.11151E-08 -4.08413E-10 1.25153E-12

(Example 7)
As shown in FIG. 19, the inner focus imaging lens of Example 7 includes a positive first lens group L1, a positive second lens group L2, a negative third lens group L3, a positive fourth lens group L4, It is the configuration of the negative fifth lens group L5, the second lens group L2 is the first focus lens group, and the fourth lens L4 is the second focus lens group. In the third lens group L3 of the inner focus imaging lens of Example 7, the positive lens arranged on the image side is the anti-vibration lens group.

An optical specification table of the inner focus imaging lens of Example 7 is shown below.
No. RD Nd ABV
1ASPH -45.6091 1.2810 1.58547 59.46
2ASPH 58.1783 13.4670
3 37.9247 4.5845 2.06011 26.94
4 1087.0454 7.8754
5 -33.1619 0.9000 1.80633 29.84
6 72.2716 1.2802
7ASPH 28.9469 7.3500 1.69661 53.20
8ASPH -27.3544 2.7020
9STOP 0.0000 3.8810
10 -42.8152 1.2000 1.85505 23.78
11 33.7973 1.7417
12ASPH 40.7465 3.7329 1.49856 81.56
13ASPH -45.6027 10.1351
14ASPH -178.9853 2.7530 1.82537 42.71
15ASPH -28.9395 1.9025
16 54.2768 1.2100 1.71828 45.78
17 17.8291 4.9894 1.85435 23.75
18 23.5671 29.6485

infinity short range
F 41.1921 36.2086
Fno 2.0600 2.3274
W 27.5161 24.9626
D(0) INF 128.9162
D(4) 7.8754 3.9207
D(8) 2.7020 6.6551
D(13) 10.1351 6.0469
D(15) 1.9025 5.9876

The aspheric coefficients of Example 7 are shown below.
No. ε *4 *6 *8 *10
1 1.00000E+00 7.37837E-06 -1.24030E-08 1.56528E-11 -7.22325E-15
2 1.00000E+00 -2.28069E-06 -6.87805E-09 -1.94934E-12 1.69529E-14
7 1.00000E+00 -1.74080E-05 8.36553E-09 -2.75833E-11 5.10058E-14
8 1.00000E+00 1.41270E-05 -1.97640E-08 4.48228E-11 -2.33347E-14
12 1.00000E+00 -1.58229E-06 -2.50994E-08 3.23867E-10 -6.01941E-13
13 1.00000E+00 3.09904E-06 2.06002E-08 6.67456E-11 1.11953E-13
14 1.00000E+00 -4.47999E-06 2.34183E-08 -6.30846E-11 -3.71892E-14
15 1.00000E+00 1.01773E-06 1.32507E-08 -2.83436E-11 -6.23085E-14

Table 1 shows the values of the conditional expressions in each example.

(Example 8)
An image pickup apparatus 100 of Example 8 includes an image pickup lens 110 and an image pickup element 120 arranged on the image plane of the image pickup lens 110, as shown in the configuration diagram of FIG. A filter F and a cover glass CG may be arranged between the imaging lens 110 and the imaging device 120 .

F filter CG cover glass IMG image plane STOP aperture stop L1 1st lens group L2 2nd lens group L3 3rd lens group L4 4th lens group

Claims (10)

A first focus lens group having a positive refractive power, and a second focus lens group having a positive refractive power arranged closer to the image than the first focus lens group, wherein the distance from an infinity object to a short distance object is provided. When focusing on , the first focus lens group moves toward the object side, and the second focus lens group moves toward the object side by a movement amount different from that of the first focus lens group,
a combined focal length of all lenses arranged between the first focus lens group and the second focus lens group is negative ;
Inner focus type imaging, characterized in that the combined focal length of all lenses arranged closer to the image side than the second focus lens group is negative, and the lens arranged closest to the object side has negative refractive power. lens. 2. The inner focus imaging lens according to claim 1, wherein the following conditional expression (1) is satisfied.
(1) 0.3 ≤ fo1 / fo2 ≤ 3.3
where fo1 is the focal length of the first focus lens group
fo2: focal length of the second focus lens group 3. The inner focus imaging lens according to claim 1, wherein the second focus lens group is composed of one lens component. 4. The camera according to any one of claims 1 to 3, further comprising a vibration reduction lens group that moves in a direction perpendicular to the optical axis between the first focus lens group and the second focus lens group. Inner focus imaging lens. 5. The inner focus imaging lens according to claim 4, wherein the following conditional expression (2) is satisfied.
(2) 0.05 ≤ |(1-βvc)×βr| ≤ 1.9
where βvc: Lateral magnification of the anti-vibration lens group when focusing on infinity;
βr: Composite lateral magnification of the lens placed on the image side of the anti-vibration lens group when focusing on infinity 6. The inner focus imaging lens according to claim 4, wherein the vibration reduction lens group is composed of one lens component. It has at least one lens element having a positive power on the object side of the first focus lens group, and satisfies the following conditional expressions (3) and (4). 1. The inner focus imaging lens according to item 1.
(3) G1dPgF ≤ 0.0282
(4) G1vd ≤ 45.0
where, G1dPgF: g-line and F-line anomalous dispersion of a lens element with positive power on the object side of the first focus lens group
G1vd: Abbe number for the d-line of the lens element with positive power on the object side of the first focus lens group One of Claims 1 to 7, characterized in that at least one lens element having negative power is provided in the first focus lens group, and the following conditional expressions (5) and (6) are satisfied. The inner focus type imaging lens according to the item.
(5) G2dPgF ≥ 0.0007
(6) G2vd ≤ 45.0
where, G2dPgF: g-line and F-line anomalous dispersion of the lens element with negative power in the first focus lens group
G2vd: Abbe number at the d-line of the negative power lens element in the first focus lens group 9. The inner focus imaging lens according to claim 1, wherein an aperture stop is arranged between the first focus lens group and the second focus lens group. An imaging apparatus comprising: the inner focusing imaging lens according to any one of claims 1 to 9; and an imaging device arranged on an image plane of the inner focusing imaging lens.

Images