JPH07261127A - Short distance correction lens equipped with vibrationproof function - Google Patents

Abstract

PURPOSE:To provide a short distance correction lens which is equipped with the vibrationproof function, relatively long in focal length, and suitable for photographs, videos, etc. CONSTITUTION:The short distance correction lens equipped with the vibrationproof function is equipped with a 1st lens group G1 with positive refractive power and a 2nd lens group G2 with negative refractive power on the object side in order from the object side, and with a final lens group GL with positive refractive power on the most image side, and, this short distance correction lens, which is focused on a short-distance body from the infinite distance side by increasing the interval between the 1st lens group G1 and 2nd lens group G2, is equipped with a displacing means which isolates vibration by moving some partial lens group GLP with positive refractive power in the final lens group GL in the direction almost at a right angle to the optical axis, and meets a condition of 0.25<¦betaM¦, where betaM is the image magnification at the shortest photographic distance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a short-distance correction lens having an anti-vibration function, and more particularly to an anti-vibration method for a short-distance correction lens (so-called microlens or macro lens). The present invention relates to a microlens having a long focal length.

[0002]

2. Description of the Related Art Conventionally, as disclosed in JP-A-1-189621, JP-A-1-191112, and JP-A-1-191113, the shooting distance is infinity or a distance close to infinity (shooting magnification). (It is close to 0)
In some cases, the entire lens group or a part of the lens group is moved in a direction substantially orthogonal to the optical axis to correct a change in image position due to camera shake or the like. In this specification, moving the lens group in a direction substantially orthogonal to the optical axis to correct a change in image position due to camera shake or the like is referred to as “anti-vibration”.

[0003]

However, with the conventional technique as described above, image stabilization cannot be performed in a sufficiently large photographing magnification (for example, -1/2 times), and even if the photographing magnification is equal to (-). There is an inconvenience that the image stabilization cannot be performed near the (1 ×) state. The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a short-distance correction lens having a vibration-proof function, which has a relatively long focal length and is suitable for photography and video. To do.

[0004]

In order to solve the above-mentioned problems, in the present invention, on the object side, in order from the object side,
A first lens group G1 having a positive refractive power and a second lens group G2 having a negative refractive power are provided, and a final lens group GL having a positive refractive power is provided on the most image side. In the short-distance correction lens in which the distance between the first lens group G1 and the second lens group G2 increases when focusing on an object, a partial lens having a positive refractive power in the final lens group GL. Equipped with a displacement means for moving the group GLP in a direction substantially orthogonal to the optical axis for vibration isolation, and satisfying the condition of 0.25 <| βM |, where βM is the shooting magnification at the shortest shooting distance. A short-distance correction lens is provided.

According to a preferred embodiment of the present invention, the focal length of the final lens group GL is fL, the focal length of the entire lens system in the infinity photographing state is f, and the partial lens group GLP in the final lens group GL. Let fLP be the focal length of
When the magnitude of the maximum amount of displacement of the partial lens group GLP in the direction orthogonal to the optical axis at the time of image stabilization is ΔSLP, 0.3 <fL / f <1.5 ΔSLP / fLP <0.1 Satisfy the condition of. Further, a fixed flare stop is provided on the optical axis for blocking unnecessary light rays when the partial lens group GLP in the final lens group GL moves in a direction substantially orthogonal to the optical axis for vibration isolation. Is preferred.

[0006]

In the present invention, the first lens group G1 having a positive refractive power is provided on the object side in order from the object side so as to be suitable for a short-distance correction lens having a relatively long focal length for photography, video, etc. And a second lens group G2 having a negative refractive power, and the final lens group GL having a positive refractive power on the most image side.
And a structure in which the distance between the first lens group G1 and the second lens group G2 increases when focusing on an object at infinity from a short distance. As a reason for adopting this configuration in the present invention, the features and advantages of this type of short-distance correction lens will be briefly described.

First, with the short-distance correction lens having the above-mentioned structure, good image forming performance can be obtained at each photographing magnification including -1/2 times and equal magnification (-1 times). Also, the second
Since the lens group G2 has a negative refractive power, the principal point of combining the first lens group G1 and the second lens group G2 can be located closer to the object side than the second lens group G2. For this reason,
It is advantageous for downsizing. Further, the amount of movement of the second lens group G2 at the time of focusing from an infinite object to a short-distance object can be made smaller than that of the conventionally used front lens paying-out method. This is advantageous.

In addition, the action of the negative refracting power of the second lens group G2 allows the entire Petzval sum to be well balanced, which is advantageous for aberration correction. The present invention is
In this way, the optimum conditions for image stabilization have been found for the short-distance correction lens of the type described above, which is suitable for photography, video, and the like.

The conditions of the present invention will be described in detail below. First of all, in the short-distance correction lens of the type described above, the first lens group G1 has the largest size, so if the first lens group G1 is an image stabilization optical system that is displaced in the direction orthogonal to the optical axis,
It is not preferable because the holding mechanism and the driving mechanism are complicated and large. Further, it is not preferable to use a lens group that moves along the optical axis during focusing, such as the second lens group G2, as an image stabilization optical system, since it complicates and enlarges the holding mechanism and the driving mechanism.

Therefore, in the present invention, the lens group closest to the image side, that is, the final lens group GL, is used because of the simplification of the mechanism of the entire lens system and the excellent aberration characteristics during image stabilization.
Among them, a structure is adopted in which a displacement means is provided in a partial lens group GLP having a positive refracting power to perform image stabilization. Less than,
The partial lens group GLP is called an "anti-vibration lens group".

The short-distance correction lens of the present invention satisfies the following conditional expression (1) in addition to the above configuration. 0.25 <| βM | (1) where βM: shooting magnification at the shortest shooting distance

Conditional expression (1) shows the short-distance focusing ability of the optical system according to the present invention as a short-distance correction lens, and at the same time, an appropriate range () for the magnitude of the photographing magnification at the shortest photographing distance for practical use. The lower limit) is specified. If the lower limit of conditional expression (1) is not reached, the shooting magnification at the shortest shooting distance becomes too small, and the short-distance focusing ability becomes insufficient, making it unsuitable for practical use. By setting the lower limit of conditional expression (1) to 0.45, it is possible to secure a sufficient short-distance focusing ability.

In order to obtain better imaging performance, it is preferable that the following conditional expressions (2) and (3) are satisfied. 0.3 <fL / f <1.5 (2) ΔSLP / fLP <0.1 (3) where fL: focal length of the final lens group GL f: focal length of the entire lens system in infinity shooting fLP : Focal length of the image stabilizing lens group GLP in the final lens group GL SLP: Maximum displacement amount in the direction orthogonal to the optical axis of the image stabilizing lens group GLP during image stabilization

Conditional expression (2) defines an appropriate range for the ratio between the focal length fL of the final lens group GL and the focal length f of the entire lens system in infinity photography.
If the upper limit of conditional expression (2) is exceeded, not only the focal length fL of the final lens group GL becomes too large and the overall lens length becomes long, which is contrary to compactness, but also spherical aberration tends to become excessive on the negative side. , Is inconvenient.

On the contrary, if the lower limit of conditional expression (2) is exceeded,
The focal length fL of the final lens group GL becomes too small, and spherical aberration tends to become excessive on the positive side in the infinity photographing state, and the fluctuation of the curvature of field at the time of focusing at a close distance becomes great. In addition, the Petzval sum tends to largely shift to the positive side, and as a result, the curvature of the image surface tends to occur in the negative direction, which is inconvenient. If the upper limit value of conditional expression (2) is set to 0.8 and the lower limit value is set to 0.45, even better imaging performance can be obtained.

Conditional expression (3) is defined by the magnitude ΔSLP of the maximum displacement amount of the image stabilizing lens group GLP during image stabilizing.
An appropriate range is defined by the ratio of the focal length fLP of LP.
If the upper limit of conditional expression (3) is exceeded, the maximum displacement amount of the image stabilization lens group GLP in the final lens group GL during image stabilization becomes too large, and as a result, the amount of aberration fluctuation during image stabilization will become large. Since it becomes large, it is inconvenient. In particular, at the peripheral position on the image plane, the difference in the optical axis direction between the best image plane in the meridional direction and the best image plane in the sagittal direction widens, which is inconvenient. If the upper limit of conditional expression (3) is set to 0.03, even better imaging performance can be obtained.

In order to obtain even better imaging performance, it is desirable to satisfy the following conditional expressions (4) and (5). WD / f <5.0 (4) | △ | / f <0.5 (5) where WD is the optical axis from the subject to the object side lens surface of the short distance correction lens in the shortest shooting distance state. Along the distance Δ: Amount of change in axial air distance between the first lens group G1 and the second lens group G2 in the infinity shooting state and the shortest shooting distance state However, the sign of the change amount Δ indicates that the axial air distance is It is positive when it increases and negative when the axial air spacing decreases.

Conditional expression (4) shows the short-distance focusing ability of the short-distance correction lens, and is defined as the optical axis from the subject to the lens surface closest to the object side of the short-distance correction lens in the shortest shooting distance state. With respect to the along distance WD, a practically applicable range is shown. If the upper limit of conditional expression (4) is exceeded,
The distance WD to the subject in the shortest shooting distance state is too large, and the short-distance focusing ability is insufficient, which makes it unsuitable for practical use. If the upper limit of conditional expression (4) is set to 3.0, it is possible to secure a more sufficient short-distance focusing ability.

If the upper limit of conditional expression (5) is exceeded, the amount of movement of the second lens group G2 during focusing will be too large, and the amount of aberration variation during focusing at a short distance will be large, which is inconvenient. In particular, spherical aberration, bending of the image surface at the peripheral position on the image surface, and astigmatism are extremely large, which is inconvenient. Moreover, the structure is mechanically complicated, which is not preferable.

In order to obtain better imaging performance and image stabilization performance, it is desirable to satisfy the following conditional expressions (6) and (7) in addition to the above-mentioned conditions. 0.5 <fLP / fL <2.5 (6) L / f <0.25 (7) where L: axial thickness of the antivibration lens group GLP

Conditional expression (6) defines an appropriate range for the ratio between the focal length fLP of the image stabilizing lens group GLP and the focal length fL of the final lens group GL. Conditional expression (6)
When the value exceeds the upper limit of, the spherical aberration is apt to be excessive on the positive side and the distortion is increased on the positive side in both cases of infinity shooting and short-range shooting, which is inconvenient.

On the contrary, if the lower limit of conditional expression (6) is exceeded,
The focal length fLP of the anti-vibration lens group GLP becomes too small,
Not only is spherical aberration excessive on the negative side, but also curvature of the image surface is likely to occur in the negative direction, which is inconvenient. Further, fluctuations of various aberrations during image stabilization become excessive, which makes it difficult to obtain good imaging performance during image stabilization, which is inconvenient. If the upper limit value of conditional expression (6) is set to 1.8 and the lower limit value is set to 1.0, even better imaging performance and image stabilization performance can be obtained.

Conditional expression (7) defines an appropriate range for the ratio of the axial thickness of the image stabilizing lens unit GLP to the focal length of the entire lens system in the infinity photographing state. If the upper limit of conditional expression (7) is exceeded, the axial thickness of the image stabilizing lens group GLP becomes too large, and as a result, the mechanism for image stabilization becomes large and complicated, which is not preferable.

When actually constructing the anti-vibration lens group GLP,
In addition to the above-mentioned conditions, it is desirable to satisfy the following conditional expressions (8) and (9). 1.5 <N + (8) 40 <ν + (9) where N + is the maximum refractive index of the positive lens components in the antivibration lens group GLP ν +: In the antivibration lens group GLP The maximum Abbe number of the Abbe numbers of the positive lens component of N + and ν + are the refractive index and the Abbe number for the d-line (λ = 587.6 nm).

If the lower limit of conditional expression (8) is not reached, spherical aberration tends to become excessively negative and distortion becomes large on the negative side both in the infinity photographing state and in the short distance photographing state. is there. In addition, since the Petzval sum also tends to shift to the positive side, the curvature of the image surface tends to increase in the negative direction, which is inconvenient.

When the value goes below the lower limit of conditional expression (9), in both the infinity state and the short-distance shooting state,
Axial chromatic aberration of short wavelength tends to be excessive on the negative side, and it becomes difficult to obtain good imaging performance.

In addition to the above conditions, it is preferable to satisfy the following conditions when actually constructing an optical system. First, if a fixed flare stop is provided on the optical axis in addition to the aperture stop, it is possible to block unnecessary light rays when the lens group is displaced across the optical axis for vibration isolation, and it is possible to prevent the occurrence of ghosts. It is possible to avoid unnecessary exposure. Further, it is desirable that the anti-vibration lens group GLP be fixed along the optical axis when focusing on a short distance so that the holding mechanism and the driving mechanism can be simplified.

When the image stabilizing lens group GLP is composed of one lens, it is desirable to use a biconvex lens or a meniscus lens having a surface having a strong curvature on the object side.
The refractive power distribution between the first lens group G1 and the second lens group G2 is also important in order to obtain good imaging performance when the entire short-distance correction lens system is constructed, and the focus of the first lens group G1 is important. If the distance and the focal length of the second lens group G2 in the infinity photographing state are f1 and f2, respectively, it is preferable to satisfy the following conditional expression (10). 1.2 <f1 / | f2 | <2.0 (10)

Further, in order to obtain good image forming performance, it is desirable to provide the aperture stop S near the second lens group G2 or the final lens group G3. Also, anti-vibration lens group GLP
Is preferably arranged on the image side of the aperture stop S. The short-distance correction lens of the present invention includes the first lens group G1 having a positive refractive power.
And a second lens group G2 having a negative refractive power and a final lens group GL having a positive refractive power, the light rays between the second lens group G2 and the final lens group GL should be substantially parallel. Is desirable.

Further, if the first lens group G1 is divided into a plurality of lens groups and the air distance between the divided lens groups is changed when focusing on a short distance, a better imaging performance can be obtained ( See the second embodiment). Furthermore, when forming the second lens group G2, it is preferable to include two or more lens groups having negative refracting power. Further, it is preferable to position the image stabilizing lens group GLP closer to the image side than the center position thereof in the final lens group GL, because fluctuations in spherical aberration during image stabilization are reduced.

When the final lens group GL having the positive refracting power closest to the image side is constructed, it is desirable to dispose a cemented lens of a negative lens and a positive lens on the most object side. Further, as the shooting magnification increases, the depth on the side of the object field becomes shallower, which causes the inconvenience of being easily out of focus. In this case, by combining the autofocus system and the short distance correction lens of the present invention, it is possible to avoid the defocus.

[0032]

EXAMPLES In each of the examples of the short-distance correction lens having a vibration-proof function according to the present invention, on the object side, in order from the object side, a first lens group G1 having a positive refractive power and a negative refractive power are provided. And a second lens group G2 having a second lens group G2, and a third lens group GL as a final lens group having a positive refractive power on the most image side
The third lens group (final lens group) GL in the short-distance correction lens in which the distance between the first lens group G1 and the second lens group G2 increases at the time of focusing from infinity to a short-distance object. Among them, there is provided a displacement means 1 for moving a part of the partial lens group GLP having a positive refracting power in a direction substantially orthogonal to the optical axis for vibration isolation.

Each embodiment of the present invention will be described below with reference to the accompanying drawings. [Embodiment 1] FIG. 1 is a diagram showing the structure of a short-distance correction lens according to the first embodiment of the present invention. The illustrated short-distance correction lens includes, in order from the object side, a first lens group G1 including a biconvex lens, a biconvex lens, and a biconcave lens, a cemented lens of a positive meniscus lens having a concave surface facing the object side, and a biconcave lens, and A second lens group G2 including a cemented lens of a positive meniscus lens having a concave surface facing the object side and a biconcave lens, a cemented lens of a biconcave lens and a biconvex lens, a positive meniscus lens having a convex surface facing the object side, and The third lens group GL is composed of a negative meniscus lens having a convex surface directed toward the object side. In the third lens group GL, a positive meniscus lens having a convex surface facing the object side constitutes a vibration-proof lens group GLP having a positive refractive power. An aperture stop S is provided in the third lens group GL as shown in the figure.

FIG. 1 shows the positional relationship between the lens groups in the infinity shooting state. When focusing on a short-distance object, the second lens group G2 moves along the optical axis along the trajectory shown by the arrow in the figure. Moving. However, the first lens group 1 and the third lens group GL are fixed in the optical axis direction. In addition, the third lens group G
The anti-vibration lens group GLP which is a part of L is appropriately moved in a direction substantially orthogonal to the optical axis by the anti-vibration mechanism 1 which is a displacement means,
Image shake caused by camera shake or the like is corrected. Example 1 is an application of the present invention to a photographic lens having a slightly long focal length.

The following table (1) lists the values of specifications of the first embodiment of the present invention. In Table (1), f is the focal length at infinity, β is the shooting magnification at short range, and F _NO
Represents the F number in the infinite state, 2ω represents the angle of view in the infinite state, and Bf represents the back focus. Furthermore, the leftmost number indicates the order of each lens surface from the object side, r
Is the radius of curvature of each lens surface, d is the distance between each lens surface, n
(D) and ν are d lines (λ = 587.6 nm), respectively.
The refractive index and the Abbe number for n (G) are g-lines (λ
= 435.8 nm).

[0036]

[Table 1] f = 200 F _NO = 4.03 2ω = 12.24 ° rd ν n (D) n (G) 1 106.1200 8.1000 69.98 1.52000 1.52908 2 -244.4800 0.5000 3 97.6400 8.5000 69.98 1.52000 1.52908 4 -107.2300 0.7000 5 -103.7400 2.4000 30.04 1.69895 1.72942 6 1192.6899 (d6 = variable) 7 -110.5700 4.0000 28.34 1.72825 1.76206 8 -55.6700 2.0000 64.10 1.51680 1.52667 9 210.7400 2.5000 10 -211.9600 2.0000 28.34 1.72825 1.76206 11 -97.7000 2.0000 64.10 53.1507 1.52 (Variable) 13 -140.6472 1.5000 35.51 1.59507 1.61681 14 84.3489 5.0000 58.54 1.61272 1.62571 15 -58.5014 45.2000 16 99.1934 6.0000 60.14 1.62041 1.63317 17 57107.6968 10.0000 18 172.1229 2.5000 49.45 1.77279 1.79232 19 79.4832 (Bf) 200.00000 -0.50000 d6 22.29075 47.29075 d12 29.58233 4.58233 Bf 65.47270 65.47270 (The positive sign of the amount of movement of the image indicates the same direction as the direction of movement of the lens) (Values corresponding to conditions) βM = -0.5 f = 200.0 fL = 120.0 fLP = 160.156 f1 = 100.0 f2 = −60.0 WD = 499.076 Δ = 25.0 L = 6.0 (1) | βM | = 0.5 (2) fL / f = 0.600 (3) ΔSLP / fLP = 0 .00750 (4) WD / f = 2.4954 (5) | Δ | / f = 0.1250 (6) fLP / fL = 1.3346 (7) L / f = 0.03 (8) N + = 1.62041 (9) ν + = 60.14 (10) f1 / │f2│ = 1.667

2 and 3 are graphs showing various aberrations in the state of infinity and in the state where the photographing magnification is -1/2. In each aberration diagram, F _NO is the F number, Y is the image height, NA is the numerical aperture, and D is the d-line (λ =
587.6 nm) and G is the g-line (λ = 435.8 nm)
Are shown respectively. Further, in the aberration diagram showing astigmatism, the solid line shows the sagittal image plane and the broken line shows the meridional image plane. As is clear from each aberration diagram, in the present example, it is understood that various aberrations are well corrected including in the case of image stabilization.

[Embodiment 2] FIG. 4 is a diagram showing the structure of a short-distance correction lens according to a second embodiment of the present invention. The illustrated short-distance correction lens has, in order from the object side, a cemented lens of a negative meniscus lens having a convex surface facing the object side and a biconvex lens, a positive meniscus lens having a convex surface facing the object side, and a convex surface facing the object side. A first lens group G1 including a cemented lens of a negative meniscus lens and a positive meniscus lens having a convex surface facing the object side, a negative meniscus lens having a convex surface facing the object side, and a positive meniscus lens having a convex surface facing the object side. And a second lens group G2 including a cemented lens of a positive meniscus lens having a concave surface facing the object side and a biconcave lens, and a negative meniscus lens having a convex surface facing the object side and a biconvex lens And a third lens group GL including a lens, a negative meniscus lens having a concave surface facing the object side, and a positive meniscus lens having a convex surface facing the object side. There.

In the third lens group GL, the positive meniscus lens having the convex surface facing the object side constitutes the image stabilizing lens group GLP having a positive refractive power. An aperture stop S is provided between the second lens group G2 and the third lens group GL.
Fixed flare stops FS are provided in the lens groups GL as shown in the figure. Further, in the first lens group G1, a cemented lens of a negative meniscus lens having a convex surface facing the object side and a biconvex lens, and a positive meniscus lens having a convex surface facing the object side constitute the front group G11, and are placed on the object side. A cemented lens of a negative meniscus lens having a convex surface and a positive meniscus lens having a convex surface facing the object side constitutes a rear group G12.

FIG. 4 shows the positional relationship between the lens groups in the infinity shooting state. When focusing on an object at a short distance, the front lens group G11 and the second lens group G1 of the first lens group G1 are shown.
2 moves on the optical axis along the trajectory shown by the arrow in the figure. However, the rear group G12 and the third lens group GL of the first lens group G1 are fixed in the optical axis direction. Also, the third lens group GL
A part of the anti-vibration lens group GLP is appropriately moved in a direction substantially orthogonal to the optical axis by the anti-vibration mechanism 1 which is a displacing means, so that the shake of the image due to camera shake or the like is corrected. The second embodiment also applies the present invention to a photographic lens having a slightly long focal length.

The following table (2) lists the values of specifications of the second embodiment of the present invention. In Table (2), f is the focal length at infinity, β is the shooting magnification at short range, and F _NO
Represents the F number in the infinite state, 2ω represents the angle of view in the infinite state, and Bf represents the back focus. Furthermore, the leftmost number indicates the order of each lens surface from the object side, r
Is the radius of curvature of each lens surface, d is the distance between each lens surface, n
And ν are the refractive index and the Abbe number for the d-line (λ = 587.6 nm), and n (G) is the g-line (λ = 43 nm).
The refractive index for 5.8 nm is shown.

[0042]

[Table 2] f = 199.997 F _NO = 4.00 2ω = 12.32 ° rd ν n (D) n (G) 1 197.7383 2.5000 33.89 1.80384 1.83464 2 85.6098 7.0000 82.52 1.49782 1.50527 3 -206.2828 0.3000 4 71.6067 6.0000 82.52 1.49782 1.50527 5 431.0537 (d5 = variable) 6 79.0168 2.5000 40.90 1.79631 1.82107 7 39.9554 8.8000 60.64 1.60311 1.61540 8 478.7420 (d8 = variable) 9 196.4322 2.0000 57.03 1.62280 1.63639 10 31.4573 5.0000 33.89 1.80384 1.83464 11-102.323. 1.80518 1.84731 13 -58.9450 2.0000 60.14 1.62041 1.63317 14 49.1628 (d14 = variable) 15 1206.1834 2.0000 31.08 1.68893 1.71783 16 69.6055 6.0000 60.14 1.62041 1.63317 17 -59.1728 46.5000 18 -72.7684 2.5000 49.45 1.77279 1.79232 19 -436.1421 0.4000 20.87279 1.79232 19 -436.1421 0.4000 20. 799.3808 (Bf) (Variable distance when focusing) f, β 199.99700 -0.50000 -1.00000 d5 6.64330 14.20990 6.64330 d8 5.14048 17.75138 37.14078 d14 45.12495 32.51405 13.12465 Bf 58.808 70 58.80870 58.80870 (Vibration stabilization data) Infinity shooting magnification Shooting magnification -1/2 -1 Moving amount of anti-vibration lens group in the direction orthogonal to the optical axis (mm) 1.00 1.00 1.00 Moving amount of image (mm ) 0.566 0.566 0.566 (The positive sign of the moving amount of the image shows the same direction as the moving direction of the lens) (Condition corresponding value) βM = -1.0 f = 200.0 fL = 120.0 fLP = 177.100 f1 = 80.000 f2 = -48.0 WD = 272.364 Δ = 32.0 L = 6.0 (1) | βM | = 1.0 (2) fL / f = 0. 600 (3) ΔSLP / fLP = 0.00565 (4) WD / f = 1.3618 (5) | Δ | / f = 0.16 (6) fLP / fL = 1.4758 (7) L / f = 0.03 (8) N + = 1.54814 (9) ν + = 45.87 (10) f1 / | f2 | = 1.667

FIGS. 5 to 6 are graphs showing various aberrations at infinity, various aberrations at a photographing magnification of -1/2, and various aberrations at a uniform photographing magnification (-1). It is a figure. In each aberration diagram, F _NO is the F number, Y is the image height, NA is the numerical aperture, and D is the d-line (λ = 5).
87.6 nm) and G indicates the g-line (λ = 435.8 nm). Further, in the aberration diagram showing astigmatism, the solid line shows the sagittal image plane and the broken line shows the meridional image plane. As is clear from each aberration diagram, in the present example, it is understood that various aberrations are well corrected including in the case of image stabilization.

[0044]

As described above, according to the present invention, it is possible to provide a short-distance correction lens having an anti-vibration function and having a relatively long focal length, which is suitable for photography and video. For this reason, hand-held photography becomes possible, which is extremely convenient at the time of actual photography, and photography can also be performed with good imaging performance under vibration conditions caused by camera shake or the like.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a short-distance correction lens according to Example 1 of the present invention.

FIG. 2 is a diagram of various types of aberration in the infinite state of the first example of FIG.

FIG. 3 is a diagram of various types of aberration when the imaging magnification of the first example of FIG. 1 is −1/2.

FIG. 4 is a diagram showing a configuration of a short-distance correction lens according to Example 2 of the present invention.

5 is a diagram of various types of aberration in the infinite state of the second example of FIG.

FIG. 6 is a diagram of various types of aberration when the imaging magnification of the second example of FIG. 4 is −1/2.

FIG. 7 is a photographing magnification of 1 × (-1 ×) in the second embodiment of FIG. 4;
FIG. 6 is a diagram of various aberrations in the state of FIG.

[Explanation of symbols]

 G1 1st lens group G2 2nd lens group GL Last lens group GLP Anti-vibration lens group 1 Displacement means (anti-vibration mechanism) S Aperture diaphragm FS Fixed flare diaphragm

Claims (7)

[Claims] 1. An object side is provided with a first lens group G1 having a positive refractive power and a second lens group G2 having a negative refractive power in order from the object side, and the most image side has a positive refractive power. In the short-distance correction lens, which is provided with a final lens group GL having a refractive power, and the distance between the first lens group G1 and the second lens group G2 increases when focusing on an object at infinity from a short distance, the final lens The partial lens group GLP having a positive refractive power in the group GL is provided with a displacement means for moving in a direction substantially orthogonal to the optical axis for vibration isolation, and the photographing magnification at the shortest photographing distance is set to βM. At this time, a short-distance correction lens characterized by satisfying the condition of 0.25 <| βM |. 2. The short-distance correction lens according to claim 1, wherein the partial lens group GLP in the final lens group GL is fixed along the optical axis when focusing on a short distance. 3. The focal length of the final lens group GL is fL
And f is the focal length of the entire lens system in the infinity shooting state, and the partial lens group GLP in the final lens group GL.
Where fLP is the focal length of the partial lens group and ΔSLP is the magnitude of the maximum displacement of the partial lens group GLP in the direction orthogonal to the optical axis at the time of image stabilization: 0.3 <fL / f <1.5Δ The short-distance correction lens according to claim 1, wherein the condition of SLP / fLP <0.1 is satisfied. 4. WD is the distance along the optical axis from the subject to the lens surface closest to the object side of the short distance correction lens in the shortest shooting distance state, and f is the focal length of the entire lens system in the infinity shooting state. , The first lens group G1 and the second lens group in the infinity shooting state and the shortest shooting distance state
The condition of WD / f <5.0 | Δ | / f <0.5 is satisfied, where Δ is the amount of change in the axial air distance from the lens group G2. The short-distance correction lens according to any one of items. 5. The focal length of the final lens group GL is fL
When the focal length of the partial lens group GLP in the final lens group GL is fLP, the axial thickness of the partial lens group GLP is L, and the focal length of the entire lens system in the infinity shooting state is f. , 0.5 <fLP / fL <2.5 L / f <0.25 is satisfied, The short-distance correction lens according to any one of claims 1 to 4, characterized in that: 6. A partial lens group G of the final lens group GL.
The maximum refractive index of the positive lens components in the LP is N +
When the maximum Abbe number of the positive lens components in the partial lens group GLP is ν +, the condition of 1.5 <N + 40 <ν + is satisfied. The short-distance correction lens according to any one of 1 to 5. 7. A fixed flare diaphragm is provided on the optical axis for blocking unnecessary light rays when the partial lens group GLP in the final lens group GL moves in a direction substantially orthogonal to the optical axis for vibration isolation. The short-distance correction lens according to claim 1, wherein the short-distance correction lens is provided.