JP2016218242A - Optical system, imaging apparatus, and lens device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact optical system excellent in optical performance up to a periphery, an imaging apparatus, and a lens device.SOLUTION: The optical system comprises, in order from an object side, a first lens group having negative refractive power and a second lens group having positive refractive power. When focusing from infinity to a short-distance object, the first lens group is moved to the object side and the second lens group is fixed. The first lens group comprises, in order from the object side, a negative meniscus lens L1 concave to an image side and a positive meniscus lens L2 convex to the image side and satisfies a predetermined condition.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical system, an imaging device, and a lens device.

  Optical systems installed in optical equipment such as cameras are required to be miniaturized and maintain the required optical performance without causing vignetting while being restricted by the shape of the housing and the position of the image sensor. There must be. In particular, it is difficult to satisfy this requirement in a wide-angle type optical system.

  Patent Document 1 proposes a three-lens optical system composed of an afocal system composed of two meniscus lenses having negative and positive refractive power and a positive lens in order from the object side. Patent Document 2 proposes an optical system including, in order from the object side, a negative lens having a concave surface facing the image side, and a meniscus lens having a positive refractive power and having a convex surface on the image side.

JP-A-8-220430 JP 2009-75141 A

  The optical system of Patent Document 1 does not consider focusing from infinity to a short distance object, and it is difficult to suppress aberration fluctuations such as chromatic aberration of magnification with respect to fluctuations in object distance. In Patent Document 2, since the refractive power of the entire lens group and each lens following the two lens groups on the object side is strong and the sensitivity to manufacturing errors is high, the assembly error when incorporating the lens into the lens barrel is increased. It becomes difficult to secure the performance to the periphery due to the influence.

  It is an object of the present invention to provide a small optical system, an imaging device, and a lens device that are excellent in optical performance up to the periphery.

The optical system of the present invention is an optical system composed of a first lens group having a negative refractive power and a second lens group having a positive refractive power in order from the object side. In focusing, the first lens group moves to the object side, the second lens group does not move, and the first lens group has negative refractive power with a concave surface facing the image side in order from the object side. The first meniscus lens is composed of a second meniscus lens having a positive refractive power with the convex surface facing the image side, and the focal length of the entire optical system is f, on the optical axis of the first meniscus lens and the second meniscus lens Is the distance D12, the radius of curvature of the object side surface of the second meniscus lens is r21, and the radius of curvature of the image side surface of the second meniscus lens is r22,
2.0 <D12 / f <4.0
−0.035 <(r22−r21) / (r22 + r21) <0
It satisfies the following condition.

  According to the present invention, it is possible to provide a small optical system, an imaging device, and a lens device that have excellent optical performance up to the periphery.

It is sectional drawing and aberration figure of the optical system of this invention. Example 1 It is explanatory drawing of the relationship between each lens of the 1st lens group in this invention, and an image side principal point position. It is sectional drawing and aberration figure of the optical system of this invention. (Example 2) It is sectional drawing and aberration figure of the optical system of this invention. (Example 3) It is sectional drawing and aberration diagram of the wide-angle side optical system of the compound eye optical system of this invention. Example 4 It is sectional drawing and aberration diagram of the telephoto side optical system of the compound eye optical system of this invention. Example 4 It is a schematic diagram explaining the method to hold | maintain the lens group of this invention integrally. Example 4

  The optical system (imaging optical system) of the present embodiment can be applied to optical equipment (an imaging device or a lens device attached to and detached from the imaging device body) such as a digital video camera and a digital still camera. The imaging apparatus includes a single-lens reflex camera, a non-reflex camera (mirrorless camera), binoculars, a telescope, a compound-eye imaging apparatus having a plurality of optical systems, and the like. Good. The optical system of the present embodiment forms an optical image of a subject on the imaging surface of the image sensor. The image sensor photoelectrically converts an optical image of a subject formed by the optical system.

  The plurality of optical systems in the compound-eye imaging apparatus may have the same focal length or different focal lengths. In addition, the compound-eye imaging device includes a single imaging element having imaging regions corresponding to a plurality of optical systems, or a plurality of imaging elements respectively corresponding to a plurality of optical systems. In addition, a lens device having a plurality of optical systems may be attached to an imaging device body having an imaging element.

  The optical system according to the present embodiment includes, in order from the object side, a first lens group having a negative refractive power and a second lens group having a positive refractive power. Further, when focusing from infinity to a short distance object, the first lens group moves to the object side, and the second lens group does not move.

  The first lens group includes, in order from the object side, a negative meniscus lens (first meniscus lens) L1 having a concave surface facing the image side, and a meniscus lens having a positive refractive power (second lens) having a convex surface facing the image side. Meniscus lens) L2. In the first lens group, the first lens group and the second lens group are arranged by placing the image side principal point of the first lens group closer to the object side so that the power balance of each group with respect to the entire length of the optical system is appropriate. The main point interval can be increased.

  FIG. 2 is a schematic diagram showing each lens of the first lens group and the image side principal point position of the first lens group. L1 and L2 represent the respective lenses constituting the first lens group, and P2 represents the imaging position of the lens L2 when a light beam parallel to the optical axis indicated by the alternate long and short dash line is incident on the first lens group. , H1 represents the image-side main plane of the first lens group.

  As shown in FIG. 2, the entire refractive power is negative, and a lens L1 having a negative refractive power on the object side of the first lens group and a lens L2 having a positive refractive power on the image side are arranged. It is possible to dispose the image side main plane H1 of one lens group closer to the object side. Further, if the distance between the lenses L1 and L2 is increased while the refractive power of the entire first lens unit is kept constant, the image formation position P2 moves further to the object side, and accordingly the image side main plane H1 also moves to the object side. To do. That is, by widening the distance between the lenses L1 and L2, the image-side principal point of the first lens group can be arranged closer to the object side.

  In the optical system of the present embodiment, it is preferable that the following conditional expression is satisfied, where the distance on the optical axis between the lens L1 and the lens L2 is D12 and the total focal length of the optical system is f.

2.0 <D12 / f <4.0 (1)
When the lower limit of conditional expression (1) is exceeded, the distance D12 between the lens L1 and the lens L2 becomes too small, the principal point distance between the first lens group and the second lens group becomes narrow, and the first lens group or the first lens group The refractive power of the two lens group becomes strong. When the refractive power of the first lens group or the second lens group is increased, the refractive power of each lens constituting the lens group is increased, so that the sensitivity to the manufacturing error is increased, and the assembly error when incorporating each lens into the lens barrel. It becomes difficult to secure the performance up to the peripheral part due to the influence of. On the contrary, if the upper limit value is exceeded, the distance D12 between the lens L1 and the lens L2 becomes too large, the front lens diameter becomes large, and the optical system and the image pickup apparatus become large, which is not preferable.

  Since the lens L2 has a meniscus shape having a positive refractive power with a convex surface facing the image side, the image-side principal point H1 of the first lens group can be disposed more on the object side. The shape of the lens L2 preferably satisfies the following conditional expression where r21 is the radius of curvature of the object side surface and r22 is the radius of curvature of the image side surface.

−0.035 <(r22−r21) / (r22 + r21) <0 (2)
When the lower limit of conditional expression (2) is exceeded, the positive refractive power of each surface becomes too strong, and the variation in field curvature at the time of focusing from the object to the closest object becomes large. On the other hand, if the upper limit is exceeded, it is difficult to place the imaging position P2 on the object side, and it becomes impossible to secure the principal point interval between the first lens group and the second lens group.

  When the first lens group satisfies the conditional expressions (1) and (2), the distance between the lenses L1 and L2 and the shape of the lens L2 can be set to appropriate values and appropriate shapes, while ensuring the desired overall length. Correction of various aberrations from on-axis to off-axis can be realized.

  When the focal length of the first lens group is f1 and the focal length of the second lens group is f2, it is preferable that the following conditional expression (3) is satisfied.

-2.6 <f1 / f2 <-1.8 (3)
When the lower limit value of conditional expression (3) is exceeded, the refractive power of the first lens group with respect to the second lens group becomes too weak, making it difficult to suppress aberration fluctuations during focusing. On the other hand, if the upper limit is exceeded, the refractive power of the first lens group becomes too strong, and it becomes difficult to correct off-axis aberrations such as lateral chromatic aberration and distortion.

  Desirably, an optical system capable of further reducing various off-axis aberrations can be provided by setting the following conditional expression (3a).

-2.5 <f1 / f2 <-1.9 (3a)
When the focal length of the lens L1 is f1n and the focal length of the lens L2 is f1p, it is preferable that the following conditional expression (4) is satisfied.

-10.0 <f1p / f1n <-5.0 (4)
When the lower limit value of conditional expression (4) is exceeded, the negative refractive power of the lens L2 becomes too weak with respect to the positive refractive power of the lens L1, and correction for off-axis aberration fluctuations such as distortion during focusing is performed. Will become difficult. On the other hand, if the upper limit is exceeded, the negative refractive power of the lens L1 is too weak, making it difficult to correct field curvature.

  Desirably, by setting the range in the following conditional expression (4a), it is possible to provide an optical system with less fluctuation in aberration during focusing.

  −9.0 <f1p / f1n <−6.0 (4a)

  FIG. 1A is a sectional view of the optical system of Example 1, and FIG. 1B is an aberration diagram thereof. In the aberration diagrams, d and g are the d-line and g-line, respectively, and ΔM and ΔS are the meridional image plane and the sagittal image plane. Lateral chromatic aberration is represented by the g-line. ω is a half angle of view, and Fno is an F number. These are also true for other embodiments.

  The optical system according to the present exemplary embodiment includes, in order from the object side, a first lens group (front group) Gr1 having a positive refractive power and a second lens group (rear group) Gr2 having a negative refractive power. An aperture stop SP is provided in the second lens group Gr2. In the present embodiment and the embodiments described later, the aperture stop SP is provided on the most object side of the second lens group Gr2. However, the position of the aperture stop SP is not limited to this, and the second lens group Gr2 includes the aperture stop SP. It is sufficient if it is provided. During focusing from infinity to a short distance object, the first lens group Gr1 moves to the object side, and the second lens group Gr2 is stationary (fixed).

  The first lens group Gr1 includes, in order from the object side, a meniscus lens L1 having a negative refractive power with a concave surface facing the image side, and a meniscus lens L2 having a positive refractive power with a convex surface facing the image side. It is configured. The lens L1 disposed closest to the object side has an aspherical surface shape at least on the object side or the image side. By using such a shape, the optical system is reduced in size and distortion is suppressed. .

  The second lens group Gr2 includes, in order from the object side, a meniscus lens L3 having a positive refractive power with a convex surface facing the object side, a biconvex positive lens, and a cemented lens of a biconvex positive lens and a negative lens. And a meniscus lens having negative refractive power. As described above, the second lens group Gr2 includes the positive lens L3 as the lens disposed closest to the object side and at least one negative lens. However, the configuration of the second lens group Gr2 is not limited to this. Absent.

  In this embodiment, by increasing the distance between the lens L1 and the lens L2 with respect to the focal length of the entire system, it is possible to achieve both downsizing and correction of off-axis aberration while securing the overall length even in a wider angle lens. Yes.

  FIG. 3A is a cross-sectional view of the optical system of Example 2, and FIG. 3B is an aberration diagram thereof.

  The optical system of the present embodiment is composed of, in order from the object side, a first lens group (front group) Gr1 having negative refractive power and a second lens group (rear group) Gr2 having positive refractive power. During focusing from infinity to a short distance object, the first lens group Gr1 moves toward the object side, and the second lens group does not move (fixed).

  The first lens group Gr1 includes, in order from the object side, a meniscus lens L1 having a negative refractive power with a concave surface facing the image side, and a meniscus lens L2 having a positive refractive power with a convex surface facing the image side. It is configured. The lens L1 disposed closest to the object side has an aspherical surface shape on at least the object side or the image side. By using such a shape, the optical system can be reduced in size and distortion can be suppressed. Yes.

  The second lens group Gr2 includes, in order from the object side, a meniscus lens L3 having a positive refractive power with a convex surface facing the object side, a biconvex positive lens, a meniscus lens having negative refractive power, a negative lens It is composed of a cemented lens of a lens and a biconvex positive lens. As described above, the second lens group Gr2 includes the positive lens L3 as the lens disposed closest to the object side and at least one negative lens. However, the configuration of the second lens group Gr2 is not limited to this. Absent.

  In this embodiment, the total length of the optical system with respect to the focal length of the entire system is secured larger than that of the first embodiment. In the second embodiment, the distance between the lens L1 and the lens L2 with respect to the focal length of the entire system and the surface shape of the lens L2 are within the ranges of the conditional expressions (1) and (2), and the size is reduced while ensuring a desired overall length. Achieves both correction of off-axis aberrations.

  4A is a sectional view of the optical system of Example 3, and FIG. 4B is an aberration diagram thereof.

  The optical system of the present embodiment is composed of, in order from the object side, a first lens group (front group) Gr1 having negative refractive power and a second lens group (rear group) Gr2 having positive refractive power. During focusing from infinity to a short distance object, the first lens group Gr1 moves toward the object side, and the second lens group does not move (fixed).

  The first lens group Gr1 includes, in order from the object side, a meniscus lens L1 having a negative refractive power with a concave surface facing the image side, and a meniscus lens L2 having a positive refractive power with a convex surface facing the image side. Composed. The lens L1 disposed closest to the object side has an aspherical surface shape on at least the object side or the image side. By using such a shape, the optical system can be reduced in size and distortion can be suppressed. Yes.

  The second lens group Gr2 includes, in order from the object side, a meniscus lens L3 having a positive refractive power with a convex surface facing the object side, a biconvex positive lens, a meniscus lens having negative refractive power, a negative lens It is composed of a cemented lens of a lens and a biconvex positive lens. As described above, the second lens group Gr2 includes the positive lens L3 as the lens disposed closest to the object side and at least one negative lens. However, the configuration of the second lens group Gr2 is not limited to this. Absent.

  In this embodiment, the distance between the lens L1 and the lens L2 with respect to the focal length of the entire system is smaller than in the other embodiments, but the surface shape of the lens L2 is more suitable for the image side principal point position of the first lens group. It is configured so that it can be placed on the object side. As described above, in Example 3, the surface shape of the lens L2 is more effectively used to achieve both reduction in size and correction of off-axis aberration while ensuring the entire length.

  In Example 4, the optical system is used as a wide-angle lens of a compound eye optical system. The compound-eye optical system in this embodiment is composed of two optical systems, that is, a wide-angle side optical system (wide single eye) and a telephoto side optical system (tele single eye).

  FIG. 5A is a cross-sectional view of the wide-angle side optical system, FIG. 5B is an aberration diagram, FIG. 6A is a cross-sectional view of the telephoto side optical system, and FIG.

  The wide-angle optical system includes, in order from the object side, a first lens group Gr1 having a negative refractive power and a second lens group Gr2 having a positive refractive power. The telephoto side optical system includes, in order from the object side, a first lens group Gr1 having negative refractive power and a second lens group Gr2 having positive refractive power.

  In the wide-angle side optical system, the first lens group Gr1 (Grn) includes, in order from the object side, a meniscus lens L1 having a negative refractive power with the convex surface facing the object side, and positive refraction with the convex surface facing the image side. It comprises a meniscus lens L2 having a force. The second lens group Gr2 (Grp) includes, in order from the object side, a biconvex positive lens L3, a positive meniscus lens having a convex surface facing the object side, a biconvex positive lens, and a negative refractive power. A cemented lens of a meniscus-shaped lens having a biconvex negative lens.

  The first lens group Gr1 of the telephoto side optical system includes, in order from the object side, a meniscus lens having a positive refractive power with the convex surface facing the object side, and a meniscus negative lens and a positive lens with the convex surface facing the object side. The cemented lens is composed of a biconvex positive lens. The second lens group Gr2 of the telephoto side optical system includes, in order from the object side, a meniscus lens having a negative refractive power with a convex surface facing the object side, and a meniscus shape having a positive refractive power with a convex surface facing the object side. It is made up of lenses. As described above, the second lens group Gr2 includes the positive lens L3 closest to the object side and includes at least one negative lens.

  The distance from the aperture stop SP of the wide-angle side optical system to the image plane IP is equal to the distance from the aperture stop SP of the telephoto side optical system to the image plane IP. When the wide-angle side optical system and the telephoto side optical system are arranged in parallel, The aperture stops SP and the image planes IP can be arranged on the same plane.

  Further, the compound eye optical system of the present embodiment has the same distance between the wide eye (W) and the tele eye (T) from the most object side surface to the image surface, and the aperture stop SP and image surface IP. The first lens group is arranged in a direction parallel to the image plane IP, and the positions thereof are substantially the same. By adopting such a configuration, it is possible to integrally hold each lens group in which each lens group of the wide single eye and the tele single eye is held by a common member. Alternatively, with this configuration, the lens arrangement positions of the wide eye and the tele eye are also close, so the lenses adjacent to each other in the vertical direction of the wide eye and the tele eye are integrally molded with a common material. It is also possible.

  FIG. 7 is a schematic diagram for explaining a method of integrally holding the first lens group Gr1 and the second lens group Gr2. In FIG. 7, each lens group is represented by one lens for simplification of the drawing. As shown in FIG. 7, the compound eye optical system of the present embodiment has a configuration in which the lens groups are integrally held by the holding means H, and the plurality of first lens groups Gr1 are integrally driven by the driving means in focusing. Yes. Drive means for moving the plurality of first lens groups by the same movement amount may be provided.

  Further, when the first lens group Gr1 is integrally driven, a plurality of focused images having the same angle of view as different subject space ranges (angles of view) can be acquired by one control by the control unit. It is preferable that the conditional expression (5) is satisfied.

0.8 <| ffi / ffh | <1.2 (5)
In the conditional expression (5), ffh and ffi are the focal lengths of the respective focus groups of the arbitrary optical systems i and h. By satisfying this conditional expression, the focus with respect to the change of the subject position in the optical systems i and h The amount of movement of the group can be made the same.

  Assuming that the wide-angle side optical system of the present embodiment is the optical system i and the telephoto side optical system is the optical system h, ffi = -20.33, ffh = 19.92 and ffi / ffh = −1.02. 5) is satisfied.

  In this embodiment, the total length of the wide eye and the position of the first lens group Gr1 are aligned with the tele eye and satisfy the conditional expression (5). Therefore, the angle of view differs from that of the common focus group drive mechanism. It is possible to realize a compound eye optical system suitable for an imaging apparatus capable of simultaneously acquiring the in-focus images.

  Hereinafter, specific numerical data of Numerical Examples 1 to 4 corresponding to the imaging wide-angle systems of Examples 1 to 4 will be shown. In each numerical example, i is the number of the surface counted from the object side, ri is the radius of curvature of the i-th optical surface (i-th surface), and di is the axial distance between the i-th surface and the (i + 1) -th surface. It is. ndi and νdi are the refractive index and Abbe number of the material of the i-th optical member with respect to the d-line, respectively. f is a focal length, Fno is an F number, and ω is a half angle of view. An interval d of 0 indicates that the front and back surfaces are joined.

  The aspherical shape is given by the following equation using R as the radius of curvature and aspherical coefficients K, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12.

X = (H ² / R) / [1+ {1− (1 + K) (H / R) 2} ^1/2 ] + A3 · H ³ + A4 · H ⁴ + A5 · H ⁵ + A6 · H ⁶ + A7 · H ⁷ + A8 · H ⁸ + A9 · H ⁹ + A10 · H ¹⁰ + A11 · H ¹¹ + A12 · H ¹²
Note that “E ± XX” in each aspheric coefficient means “× 10 ^{± XX} ”.

  Table 1 summarizes the relationship between the above-described conditional expressions and numerical examples. For Example 4, values corresponding to the conditional expression are shown only for the wide single eye.

  The focal length, F number, and angle of view represent values when focusing on an object at infinity. BF is a value obtained by converting the distance from the final lens surface to the image plane into air. In the cross-sectional view of each embodiment, the glass block GB arranged closest to the image side corresponds to a CCD protective glass, a low-pass filter, or the like.

(Numerical example 1)
Unit mm
Surface data surface number rd nd vd Effective diameter
1 * 11.222 1.40 1.55332 71.7 18.57
2 * 4.020 14.76 11.66
3 -8.953 2.93 1.48749 70.2 5.11
4 -8.393 1.50 4.39
5 (Aperture) ∞ 0.50 3.49
6 * 10.459 1.70 1.58913 61.2 3.53
7 19.671 1.35 3.71
8 13.719 1.85 1.58313 59.4 4.77
9 -5.513 0.34 5.07
10 11.363 1.79 1.49700 81.5 4.91
11 -5.475 0.80 1.84666 23.8 4.68
12 -35.890 0.19 4.68
13 31.382 0.70 1.85400 40.4 4.63
14 * 5.875 2.50 4.49
15 ∞ 1.10 1.51633 64.1 6.01
16 ∞ 6.54
Image plane ∞

Aspheric data 1st surface
K = -5.79997e-001 A 4 = -4.53155e-004 A 6 = 4.34045e-006 A 8 = -2.53030e-008
A10 = 7.48755e-011

Second side
K = -6.05643e-001 A 4 = -3.74842e-004 A 6 = -1.16781e-005 A 8 = 2.91941e-007
A10 = -6.42497e-009

6th page
K = -5.78386e + 001 A 4 = 4.56029e-003 A 6 = -1.36944e-003 A 8 = 2.16220e-004
A10 = -1.83887e-005

14th page
K = -4.35595e-001 A 4 = 1.91371e-003 A 6 = 3.76363e-005 A 8 = 1.01001e-005
A10 = -5.24423e-008

Various data focal length 3.80
F number 2.88
Half angle of view 45.56
Statue height 3.88
Total lens length 35.00
BF 1.60

Entrance pupil position 8.64
Exit pupil position -7.90
Front principal point position 10.92
Rear principal point position -2.20

Lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 -19.45 19.09 -3.45 -30.41
2 5 8.32 12.82 -0.47 -8.35

Single lens Data lens Start surface Focal length
1 1 -12.16
2 3 101.37
3 6 35.48
4 8 6.99
5 10 7.71
6 11 -7.72
7 13 -8.57
8 15 0.00

(Numerical example 2)
Unit mm

Surface data surface number rd nd vd Effective diameter
1 * 13.209 1.50 1.55332 71.7 14.91
2 * 4.170 13.03 9.83
3 -8.104 2.93 1.48749 70.2 4.79
4 -7.573 1.50 4.44
5 (Aperture) ∞ 0.50 4.46
6 7.219 1.80 1.58313 59.4 4.73
7 16.303 0.10 4.92
8 5.268 2.40 1.49700 81.5 5.14
9 -147.261 0.10 4.91
10 * 7.843 0.91 1.73077 40.5 4.81
11 4.684 0.56 4.45
12 22.673 0.98 1.80000 29.8 4.48
13 3.682 3.50 1.49700 81.5 4.56
14 -14.905 2.50 5.58
15 ∞ 1.10 1.51633 64.1 6.78
16 ∞ 7.09
Image plane ∞

Aspheric data 1st surface
K = 7.65765e-001 A 4 = -8.23324e-004 A 6 = 2.10837e-005 A 8 = -3.34455e-007
A10 = 2.31080e-009

Second side
K = -3.70130e-001 A 4 = -1.09840e-003 A 6 = -8.40951e-006 A 8 = 1.29694e-006
A10 = -5.89550e-008

10th page
K = 0.00000e + 000 A 4 = -1.43367e-003 A 6 = -4.28979e-005 A 8 = -1.48089e-006
A10 = 9.11254e-008

Various data focal length 5.00
F number 2.88
Half angle of view 37.78
Statue height 3.88
Total lens length 35.01
BF 1.60

Entrance pupil position 8.17
Exit pupil position -10.40
Front principal point position 11.09
Rear principal point position -3.40

Lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 -19.98 17.46 -4.01 -29.71
2 5 10.11 14.45 -0.68 -11.04

Single lens Data lens Start surface Focal length
1 1 -11.70
2 3 84.38
3 6 20.71
4 8 10.29
5 10 -18.10
6 12 -5.62
7 13 6.34
8 15 0.00

(Numerical Example 3)
Unit mm

Surface data surface number rd nd vd Effective diameter
1 * 12.972 1.50 1.55332 71.7 14.17
2 * 4.141 10.51 9.35
3 -8.277 4.51 1.48749 70.2 4.97
4 -8.261 1.50 4.24
5 (Aperture) ∞ 0.50 4.39
6 7.249 1.80 1.58313 59.4 4.85
7 17.565 0.13 5.03
8 5.159 2.30 1.49700 81.5 5.28
9 -56.678 0.10 5.02
10 * 8.409 0.91 1.73077 40.5 4.89
11 4.393 0.63 4.49
12 25.284 0.98 1.80000 29.8 4.52
13 3.959 3.50 1.49700 81.5 4.66
14 -11.547 2.50 5.70
15 ∞ 1.10 1.51633 64.1 6.85
16 ∞ 7.27
Image plane ∞

Aspheric data 1st surface
K = 1.66293e + 000 A 4 = -8.28783e-004 A 6 = 2.08475e-005 A 8 = -3.82028e-007
A10 = 2.58986e-009

Second side
K = -3.15226e-001 A 4 = -1.10940e-003 A 6 = -1.15060e-005 A 8 = 1.67109e-006
A10 = -9.16521e-008

10th page
K = 0.00000e + 000 A 4 = -1.58631e-003 A 6 = -4.52009e-005 A 8 = -1.72448e-006
A10 = 1.40540e-007

Various data focal length 5.00
F number 2.88
Half angle of view 37.78
Statue height 3.88
Total lens length 34.07
BF 1.60

Entrance pupil position 7.82
Exit pupil position -10.95
Front principal point position 10.83
Rear principal point position -3.40

Lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 -19.84 16.52 -4.16 -28.72
2 5 10.07 14.45 -0.05 -11.00

Single lens Data lens Start surface Focal length
1 1 -11.70
2 3 93.96
3 6 19.89
4 8 9.63
5 10 -13.91
6 12 -5.99
7 13 6.41
8 15 0.00

(Numerical example 4)
Wide eye unit mm

Surface data surface number rd nd vd Effective diameter
1 * 7.404 1.30 1.55332 71.7 14.08
2 * 3.200 10.31 9.19
3 -7.045 2.96 1.48749 70.2 5.70
4 -6.679 1.50 5.48
5 (Aperture) ∞ 0.50 3.58
6 * 13.012 3.00 1.55332 71.7 3.92
7 -8.146 0.31 4.98
8 -83.682 2.10 1.49700 81.5 5.18
9 -5.101 0.10 5.48
10 31.259 1.71 1.49700 81.5 5.17
11 -6.100 0.80 1.84666 23.8 4.89
12 -12.542 0.10 4.84
13 -27.930 0.70 1.85400 40.4 4.74
14 * 6.238 2.50 4.56
15 ∞ 1.10 1.51633 64.1 6.04
16 ∞ 6.57
Image plane ∞

Aspheric data 1st surface
K = -5.79997e-001 A 4 = -1.15761e-003 A 6 = 1.54266e-005 A 8 = -8.19803e-008
A10 = -1.10277e-010

Second side
K = -6.05643e-001 A 4 = -1.33299e-003 A 6 = -4.73214e-006 A 8 = -7.39960e-007
A10 = 3.09526e-008

6th page
K = -5.78386e + 001 A 4 = 9.45634e-004 A 6 = -5.68033e-004 A 8 = 6.51556e-005
A10 = -5.52108e-006

14th page
K = -4.35595e-001 A 4 = 2.17226e-003 A 6 = 1.20849e-004 A 8 = -4.57029e-006
A10 = 5.79376e-007

Various data focal length 4.40
F number 2.88
Half angle of view 41.37
Statue height 3.88
Total lens length 30.60
BF 1.60

Entrance pupil position 7.64
Exit pupil position -7.45
Front principal point position 9.90
Rear principal point position -2.80

Lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 -20.33 14.58 -4.00 -25.73
2 5 8.26 12.92 -1.13 -8.45

Single lens Data lens Start surface Focal length
1 1 -11.45
2 3 72.17
3 6 9.54
4 8 10.83
5 10 10.43
6 11 -14.88
7 13 -5.91
8 15 0.00

Tele eye unit mm

Surface data surface number rd nd vd Effective diameter
1 * 12.459 2.30 1.55332 71.7 12.65
2 * 55.949 4.21 12.09
3 12.550 0.76 1.72047 34.7 8.55
4 6.251 2.40 1.49700 81.5 7.57
5 15.618 2.41 6.61
6 22.631 1.50 1.67790 55.3 5.73
7 -1218.490 1.50 5.35
8 (Aperture) ∞ 1.51 4.61
9 * 43.453 0.70 1.58313 59.4 4.76
10 6.355 3.69 4.77
11 * 7.011 1.90 1.85135 40.1 7.18
12 9.435 4.01 6.87
13 ∞ 1.10 1.51633 64.1 8.33
14 ∞ 1.60 8.46
Image plane ∞

Aspheric data 1st surface
K = 6.31393e-001 A 4 = -4.37315e-005 A 6 = -1.22774e-007 A 8 = -9.35480e-009
A10 = 3.52194e-011

Second side
K = -3.41126e + 001 A 4 = 5.89862e-005 A 6 = 6.47254e-008 A 8 = -7.02093e-009
A10 = 1.02481e-010

9th page
K = 8.83136e + 001 A 4 = 1.38291e-004 A 6 = -2.27663e-005 A 8 = 2.98008e-006
A10 = -1.66891e-007

11th page
K = 0.00000e + 000 A 4 = -1.58771e-004 A 6 = -1.89942e-006 A 8 = 1.81385e-007
A10 = -7.14087e-009

Various data focal length 27.80
F number 2.88
Half angle of view 7.94
Statue height 3.88
Total lens length 29.60
BF 1.60

Entrance pupil position 26.19
Exit pupil position -11.37
Front principal point position -5.62
Rear principal point position -26.20

Lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 19.92 13.58 3.45 -9.12
2 8 -32.66 12.92 0.04 -11.32

Single lens Data lens Start surface Focal length
1 1 28.43
2 3 -18.21
3 4 19.33
4 6 32.79
5 9 -12.86
6 11 23.57
7 13 0.00

  Although the embodiments of the present invention have been described above, the present invention can be variously modified and changed within the scope of the gist thereof.

  The present invention can be applied to the use of an imaging apparatus such as a digital still camera or a digital video camera.

Gr1: first lens group, Gr2: second lens group, SP: aperture stop, L1: meniscus lens (first meniscus lens), L2: meniscus lens (second meniscus lens)

Claims (13)

An optical system including, in order from the object side, a first lens group having a negative refractive power and a second lens group having a positive refractive power,
During focusing from infinity to a short distance object, the first lens group moves to the object side, and the second lens group is stationary,
The first lens group includes, in order from the object side, a first meniscus lens having a negative refractive power with a concave surface facing the image side, and a second meniscus lens having a positive refractive power with a convex surface facing the image side.
The focal length of the entire optical system is f, the distance on the optical axis between the first meniscus lens and the second meniscus lens is D12, the radius of curvature of the object side surface of the second meniscus lens is r21, the second When the radius of curvature of the image side surface of the meniscus lens is r22,
2.0 <D12 / f <4.0
−0.035 <(r22−r21) / (r22 + r21) <0
An optical system characterized by satisfying the following conditions.   The optical system according to claim 1, wherein the second lens group includes a positive lens that is a lens disposed closest to the object side and at least one negative lens. When the focal length of the first lens group is f1, and the focal length of the second lens group is f2,
-2.6 <f1 / f2 <-1.8
The optical system according to claim 1, wherein the following condition is satisfied. When the focal length of the first meniscus lens is f1n and the focal length of the second meniscus lens is f1p,
-10.0 <f1p / f1n <-5.0
The optical system according to claim 1, wherein the following condition is satisfied.   The optical system according to claim 1, wherein the second lens group further includes an aperture stop.   The optical system according to claim 5, wherein the aperture stop is disposed closest to the object side of the second lens group.   7. The optical system according to claim 1, wherein an object-side surface of the first meniscus lens has an aspherical shape.   An imaging apparatus comprising the optical system according to claim 1.   A lens apparatus comprising the optical system according to claim 1. A plurality of optical systems including the optical system according to any one of claims 1 to 7;
An image pickup apparatus comprising: at least one image pickup device that photoelectrically converts an optical image formed by the plurality of optical systems.   The imaging apparatus according to claim 10, further comprising a holding unit that integrally holds the plurality of first lens groups of the plurality of optical systems.   The imaging device according to claim 10 or 11, wherein the plurality of first lens groups of the plurality of optical systems are formed by integrally molding lenses adjacent to each other in a direction perpendicular to each optical axis. A lens device attached to and detached from the imaging device body,
A plurality of optical systems including the optical system according to any one of claims 1 to 7,
The lens apparatus according to claim 1, wherein the imaging apparatus main body includes at least one imaging element that photoelectrically converts an optical image formed by the plurality of optical systems.