JP6044694B2 - Short-range correction lens system - Google Patents

Description

  The present invention relates to a short distance correction lens system capable of photographing from infinity to a short distance.

  In a general photographing lens system, the photographing distance as a design standard is set to infinity or a low magnification of 0.1 times or less (0 to −0.1 times). In addition, since the entire lens system is integrally extended during focusing, aberration variation is large at close distances exceeding 0.5 × (−0.5 to −1.0 ×), and good optical performance can be maintained. It was difficult. Therefore, in order to enable shooting of an object at a short distance from a shooting magnification of 0.5 times to an equal magnification, a plurality of (two to three) lens groups are independently moved at different ratios to bring about focusing. A photographic lens system that employs a floating mechanism that suppresses aberration fluctuations has been proposed (Patent Documents 1 and 2).

  On the other hand, a short-distance correction lens system equipped with an anti-vibration function that corrects changes in the image position due to camera shake, etc. by displacing a part of the lens system (moving in the direction orthogonal to the optical axis) and displacing the image formation position. Proposed. In a short-distance correction lens system having an anti-vibration function, it is required that the decentration aberration generated due to the decentration of the anti-vibration lens group is suppressed to be small and the optical performance is maintained well. In addition, in order to reduce the burden on the mechanism for decentering the image stabilizing lens group, the image stabilizing lens group is reduced in size and weight, and the displacement of the image point relative to the amount of eccentricity of the image stabilizing lens group (decentering sensitivity) is increased. It is desirable to do.

  In Patent Document 3, a first lens group having a positive refractive power, an aperture stop, a second lens group having a positive refractive power, and a third lens group having a negative refractive power are sequentially arranged from the object side. A short-distance correction lens system with a vibration function is disclosed. In this short distance correction lens system, the first lens group and the second lens group are independently moved to focus from an infinite object to a short distance object, and a part of the third lens group that does not move during focusing is prevented. It is a vibration lens group.

  However, in this configuration, the third lens group positioned away from the aperture stop is not an object side lens group (first lens group, second lens group) having a good symmetry with respect to the aperture stop. Since a part of the lens is used as an anti-vibration lens group, off-axis decentration aberration is greatly generated when the anti-vibration lens group is decentered.

  In Patent Document 4, a first lens group having a positive refractive power, a second lens group having a negative refractive power including an aperture stop, and a third lens group having a positive refractive power are sequentially arranged from the object side. A photographing lens with a vibration function is disclosed. In this photographic lens system, a part of the second lens group in the vicinity of the aperture stop is used as an anti-vibration lens group.

  However, in this configuration, focusing from an infinite object to a close object is performed by independently moving the three lens groups of the first lens group to the third lens group, so that the focus mechanism system is complicated. It will increase in size. Further, since the movement amount (feeding amount) of the entire lens system is too large, it is not practically preferable, and decentering aberration due to tilting of the focus lens group is likely to occur. Here, “eccentric aberration” and “eccentric aberration” are aberrations that occur when the former is caused by, for example, decentering of the anti-vibration lens group (positive displacement to achieve the purpose of image blur correction). For example, aberrations that occur due to tilting of the focus lens group or manufacturing errors (unintentional negative displacement), all of which remain unchanged in that they affect the performance of the optical system (common). .

JP-A-6-130291 JP 2008-20656 A JP 7-261126 A Japanese Patent Laid-Open No. 9-218349

  The present invention has been completed on the basis of the above awareness of problems, and corrects aberration fluctuations well from infinity to short distances (shooting magnification of 0.5 times or more) while simplifying and downsizing the focus mechanism system. To provide a short-range correction lens system capable of obtaining excellent optical performance by suppressing aberration fluctuations (especially off-axis aberration fluctuations such as curvature of field and lateral chromatic aberration) when the lens group is decentered or decentered. With the goal.

In one embodiment, the short distance correction lens system of the present invention includes, in order from the object side, a first lens group having a positive refractive power and a second lens group having a negative refractive power, and is close to an object at infinity. In the short-distance correction lens system in which the first lens unit and the second lens unit move to the object side with different movement amounts during focusing on the object, the first lens unit is moved in order from the object side to the first lens having a positive refractive power. 1a lens group, 1b lens group with negative refractive power, aperture stop, and 1c lens group with positive refractive power; the 1b lens group has a negative negative side on the image side located in order from the object side It is characterized by comprising a cemented lens of a lens and a positive lens concave on the image side; and satisfying the following conditional expression (2).
_{(2) 0 <νd 1bn -νd} 1bp <20
However,
νd _1bn : Abbe number for the d-line of the negative lens in the 1b lens group,
νd _1bp : Abbe number for the d-line of the positive lens in the 1b lens group,
It is.

The short distance correcting lens system of the present invention preferably satisfies the following conditional expression (2 ′) within the conditional expression range of conditional expression (2).
_{(2 ') 0 <νd 1bn} -νd 1bp <15

It is preferable that the short distance correction lens system of the present invention satisfies the following conditional expression (1).
(1) νd _1bn > 30
However,
νd _1bn : Abbe number for the d-line of the negative lens in the 1b lens group,
It is.

It is preferable that the short distance correction lens system of the present invention satisfies the following conditional expressions (3) and (4).
(3) nd _1bn <1.7
(4) nd _1bp > 1.8
However,
nd _1bn : refractive index with respect to d-line of the negative lens in the 1b lens group,
nd _1bp : refractive index of the positive lens in the 1b lens group with respect to d-line,
It is.

In another aspect, the short distance correction lens system of the present invention includes a first lens group having a positive refractive power and a second lens group having a negative refractive power in order from the object side, and is a short distance from an object at infinity. In the short-distance correction lens system in which the first lens unit and the second lens unit move to the object side with different movement amounts during focusing on the object, the first lens unit is moved in order from the object side to the first lens having a positive refractive power. 1a lens group, 1b lens group having negative refractive power, aperture stop, and 1c lens group having positive refractive power; the 1b lens group is composed of a negative single lens concave on the image side; And satisfying the following conditional expression (5).
(5) νd _1b > 45
However,
νd _1b : Abbe number for the d-line of the negative single lens in the 1b lens group,
It is.

The short-distance correction lens system of the present invention preferably satisfies the following conditional expressions (6) and (7).
(6) 2.5 <β _1b <3.2
(7) 0.35 <β _R <0.50
However,
β _1b : lateral magnification of the 1b lens group at infinity shooting,
β _R : lateral magnification of the lens system (the first c lens group and the second lens group) on the image side from the 1b lens group at the time of photographing at infinity,
It is.

It is preferable that the short distance correcting lens system according to the present invention satisfies the following conditional expression (8).
(8) 1.9 <| f2 / f1 | <3.9 (f2 <0)
However,
f1: Focal length [mm] of the first lens group,
f2: Focal length [mm] of the second lens group,
It is.

The short-distance correction lens system of the present invention preferably satisfies the following conditional expression (9).
(9) 0.74 <Δd2 / Δd1 <0.88
However,
Δd1: Amount of movement [mm] of the first lens unit during focusing from an object at infinity to a near object
Δd2: the amount of movement [mm] of the second lens unit during focusing from an infinitely distant object to a close object;
It is.

  According to the present invention, while simplifying and miniaturizing the focus mechanism system, aberration variations are corrected well from infinity to a close distance (shooting magnification of 0.5 times or more), and aberrations when the lens group is decentered or decentered. It is possible to provide a short-distance correction lens system capable of obtaining excellent optical performance by suppressing fluctuations (particularly off-axis aberration fluctuations such as field curvature and lateral chromatic aberration).

It is a lens block diagram in the state where there is no decentering of a vibration-proof lens group in the infinite distance photographing state of Numerical Example 1 of the short distance correction lens system according to the present invention. FIG. 2 is a diagram illustrating various aberrations in the configuration of FIG. 1. FIG. 2 is a lateral aberration diagram in the configuration of FIG. 1. FIG. 3 is a lens configuration diagram in a state in which the anti-vibration lens group is not decentered in the close-up shooting state of the numerical example 1; FIG. 5 is a diagram illustrating various aberrations in the configuration of FIG. 4. FIG. 5 is a lateral aberration diagram in the configuration of FIG. 4. FIG. 7 is a lateral aberration diagram when the image stabilizing lens unit is decentered in the infinite distance photographing state of the short-range correction lens system according to the numerical example 1. 6 is a lateral aberration diagram when the image stabilizing lens unit is decentered in the close-up shooting state of the short-range correction lens system according to the numerical example 1. FIG. It is a lens block diagram in the state where there is no decentration of a vibration-proof lens group in the infinite distance photographing state of Numerical Example 2 of the short distance correction lens system according to the present invention. FIG. 10 is a diagram of various aberrations in the configuration of FIG. 9. FIG. 10 is a lateral aberration diagram in the configuration of FIG. 9. It is a lens block diagram in the state where there is no decentration of an anti-vibration lens group in the short distance photographing state of the numerical example 2; FIG. 13 is a diagram illustrating various aberrations in the configuration of FIG. 12. FIG. 13 is a lateral aberration diagram in the configuration of FIG. 12. FIG. 10 is a lateral aberration diagram when the image stabilizing lens unit is decentered in the infinite distance photographing state of the short-range correction lens system according to the second numerical example. FIG. 12 is a lateral aberration diagram when the image stabilizing lens unit is decentered in the close-up shooting state of the short-range correction lens system according to the second numerical value example. It is a lens block diagram in the state where there is no decentration of a vibration-proof lens group in the infinite distance photographing state of Numerical Example 3 of the short distance correction lens system according to the present invention. FIG. 18 is a diagram illustrating various aberrations in the configuration of FIG. 17. FIG. 18 is a lateral aberration diagram in the configuration of FIG. 17. It is a lens block diagram in the state where there is no decentration of an anti-vibration lens group in the short distance photographing state of the numerical example 3. FIG. 21 is a diagram illustrating various aberrations in the configuration in FIG. 20. FIG. 21 is a lateral aberration diagram in the configuration of FIG. 20. FIG. 11 is a lateral aberration diagram when the vibration-proof lens unit is decentered in the infinite distance photographing state of the short-range correction lens system according to the numerical example 3. FIG. 12 is a lateral aberration diagram when the image stabilizing lens unit is decentered in the close-up shooting state of the short-range correction lens system according to Numerical Example 3; It is a lens block diagram in the state where there is no decentration of an anti-vibration lens group in the infinite distance photographing state of Numerical Example 4 of the short distance correction lens system according to the present invention. FIG. 26 is a diagram illustrating various aberrations in the configuration in FIG. 25. FIG. 26 is a lateral aberration diagram in the configuration of FIG. 25. It is a lens block diagram in the state where there is no decentration of an anti-vibration lens group in the short distance photographing state of the numerical example 4; FIG. 29 is a diagram of various aberrations in the configuration of FIG. 28. FIG. 29 is a lateral aberration diagram in the configuration of FIG. 28. FIG. 12 is a lateral aberration diagram when the vibration-proof lens unit is decentered in the infinite distance photographing state of the short-distance correction lens system according to Numerical Example 4; FIG. 11 is a lateral aberration diagram when the image stabilizing lens unit is decentered in the close-up shooting state of the short-range correction lens system according to Numerical Example 4; It is a lens block diagram in the state where there is no decentration of an anti-vibration lens group in the infinite distance photographing state of Numerical Example 5 of the short distance correction lens system according to the present invention. FIG. 34 is a diagram of various aberrations in the configuration of FIG. 33. FIG. 34 is a lateral aberration diagram in the configuration of FIG. 33. It is a lens block diagram in the state where there is no decentration of an anti-vibration lens group in the short distance photographing state of the same numerical value example 5. FIG. 37 is a diagram showing various aberrations in the configuration of FIG. 36. FIG. 37 is a lateral aberration diagram in the configuration of FIG. 36. FIG. 11 is a lateral aberration diagram when the image stabilizing lens unit is decentered in the infinite distance photographing state of the short distance correction lens system according to the numerical example 5. FIG. 12 is a lateral aberration diagram when the image stabilizing lens unit is decentered in the close-up shooting state of the short-range correction lens system according to the numerical value example 5. It is a lens block diagram in the state where there is no decentration of a vibration-proof lens group in the infinite point photographing state of Numerical Example 6 of the short distance correction lens system according to the present invention. FIG. 42 is a diagram of various aberrations in the configuration of FIG. 41. FIG. 42 is a lateral aberration diagram for the configuration in FIG. 41. It is a lens block diagram in the state where there is no decentration of an anti-vibration lens group in the short distance photographing state of the same numerical value example 6. FIG. 45 is a diagram of various aberrations in the configuration of FIG. 44. FIG. 45 is a lateral aberration diagram in the configuration of FIG. 44. FIG. 12 is a lateral aberration diagram when the vibration-proof lens unit is decentered in the infinite distance photographing state of the short-distance correction lens system according to Numerical Example 6; FIG. 12 is a lateral aberration diagram when the image stabilizing lens unit is decentered in the close-up shooting state of the close-up lens system according to the sixth numerical example. It is a lens block diagram in the state where there is no decentration of a vibration-proof lens group in the infinite point photographing state of Numerical Example 7 of the short distance correction lens system according to the present invention. FIG. 50 is a diagram of various aberrations in the configuration of FIG. 49. FIG. 50 is a transverse aberration diagram for the structure in FIG. 49. It is a lens block diagram in the state where there is no decentration of a vibration-proof lens group in the short distance photographing state of the same numerical value example 7. FIG. 53 is a diagram of various aberrations in the configuration of FIG. 52. FIG. 53 is a lateral aberration diagram in the configuration of FIG. 52. FIG. 10 is a lateral aberration diagram when the vibration-proof lens unit is decentered in the infinite distance photographing state of the short-range correction lens system according to the seventh numerical example. FIG. 12 is a lateral aberration diagram when the vibration-proof lens unit is decentered in the close-up shooting state of the short-range correction lens system according to Numerical Example 7; It is a lens block diagram in the state where there is no decentration of a vibration-proof lens group in the infinite distance photographing state of Numerical Example 8 of the short distance correction lens system according to the present invention. FIG. 58 is a diagram of various aberrations in the configuration in FIG. 57. FIG. 58 is a transverse aberration diagram for the structure in FIG. 57. It is a lens block diagram in the state where there is no decentration of an anti-vibration lens group in the short distance photographing state of the numerical value example 8. FIG. 61 is a diagram illustrating various aberrations in the configuration in FIG. 60. FIG. 61 is a lateral aberration diagram in the configuration of FIG. 60. FIG. 12 is a lateral aberration diagram when the vibration-proof lens unit is decentered in the infinite distance photographing state of the short-distance correction lens system according to Numerical Example 8; 10 is a lateral aberration diagram when the image stabilizing lens unit is decentered in the close-up shooting state of the short-range correction lens system according to Numerical Example 8; FIG. It is a lens block diagram in the state in which there is no decentration of the vibration-proof lens group in the infinite distance photographing state of Numerical Example 9 of the short distance correction lens system according to the present invention. FIG. 66 is a diagram of various aberrations in the configuration of FIG. 65. FIG. 66 is a transverse aberration diagram for the configuration in FIG. 65. It is a lens block diagram in the state where there is no decentration of the anti-vibration lens group in the short-distance photographing state of the same numerical value example 9. FIG. 69 is a diagram of various aberrations in the configuration of FIG. 68. FIG. 69 is a transverse aberration diagram for the structure of FIG. 68. FIG. 10 is a lateral aberration diagram when the vibration-proof lens unit is decentered in the infinite distance photographing state of the short-range correction lens system according to Numerical Example 9; 10 is a lateral aberration diagram when the image stabilizing lens unit is decentered in the close-up shooting state of the short-range correction lens system according to Numerical Example 9; FIG. It is a lens block diagram in the state where there is no decentration of the vibration-proof lens group in the infinity photographing state of Numerical Example 10 of the short distance correction lens system according to the present invention. FIG. 74 is a diagram of various aberrations in the configuration of FIG. 73. FIG. 74 is a transverse aberration diagram for the structure in FIG. 73. It is a lens block diagram in the state where there is no decentration of an anti-vibration lens group in the short distance photographing state of the same numerical value example 10. FIG. 77 is a diagram of various aberrations in the configuration of FIG. 76. FIG. 77 is a transverse aberration diagram for the configuration in FIG. 76. FIG. 12 is a lateral aberration diagram when the image stabilizing lens unit is decentered in the infinite distance photographing state of the short-distance correction lens system according to Numerical Example 10; FIG. 16 is a lateral aberration diagram when the vibration-proof lens unit is decentered in the close-up shooting state of the short-range correction lens system according to Numerical Example 10; It is a lens block diagram in the state where there is no decentration of a vibration-proof lens group in the infinite distance photographing state of Numerical Example 11 of the short distance correction lens system according to the present invention. It is an aberration diagram in the configuration of FIG. FIG. 82 is a transverse aberration diagram for the structure of FIG. 81. It is a lens block diagram in the state where there is no decentration of an anti-vibration lens group in the short distance photographing state of the same numerical value example 11. FIG. 85 is a diagram of various aberrations in the configuration of FIG. 84. FIG. 85 is a transverse aberration diagram for the structure in FIG. 84. FIG. 22 is a lateral aberration diagram when the vibration-proof lens unit is decentered in the infinite distance photographing state of the short-distance correction lens system according to Numerical Example 11; 12 is a lateral aberration diagram when the image stabilizing lens unit is decentered in the close-up shooting state of the short-range correction lens system according to Numerical Example 11; FIG. It is a lens block diagram in the state where there is no decentration of a vibration-proof lens group in the infinite distance photographing state of Numerical Example 12 of the short distance correction lens system according to the present invention. FIG. 90 is a diagram of various aberrations in the configuration of FIG. FIG. 90 is a transverse aberration diagram for the structure of FIG. It is a lens block diagram in the state where there is no decentration of an anti-vibration lens group in the short distance photographing state of the numerical example 12; FIG. 93 is a diagram of various aberrations in the configuration of FIG. 92. FIG. 93 is a transverse aberration diagram for the structure of FIG. 92. FIG. 22 is a lateral aberration diagram when the vibration-proof lens unit is decentered in the infinite distance photographing state of the short-distance correction lens system according to Numerical Example 12; FIG. 16 is a lateral aberration diagram when the vibration-proof lens unit is decentered in the close-up shooting state of the short-range correction lens system according to Numerical Example 12; It is a simple movement figure which shows the movement locus | trajectory in the case of focusing from an infinite distance object to a short distance object of the short distance correction lens system by this invention.

  As shown in the simplified movement diagram of FIG. 97, the short-range correction lens system of the present embodiment includes 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. Consists of. The first lens group G1, in order from the object side, includes a first-a lens group G1a having a positive refractive power, a first-b lens group G1b having a negative refractive power, an aperture stop S, and a first-c lens group G1c having a positive refractive power. Become. I is the image plane.

  In the short distance correction lens system of the present embodiment, as shown in the simplified movement diagram of FIG. 97, when focusing from an object at infinity to a short distance object, the first lens group G1 and the second lens group G2 have different amounts of movement. Move to the object side (feeding out) with (feeding amount). The moving amount (feeding amount) of the first lens group G1 is larger than the moving amount (feeding amount) of the second lens group G2.

  The first-a lens group G1a is composed of three lenses, ie, a negative lens 11, a positive lens 12, and a positive lens 13, in order from the object side through the numerical example 1-12. The negative lens 11 and the positive lens 13 are spherical lenses through all numerical examples 1-12. The positive lens 12 is a spherical lens in Numerical Examples 1-4 and 6-12, and the surface on the object side is an aspherical surface in Numerical Example 5.

In Numerical Example 1-6, the first-b lens group G1b is a cemented lens of a negative lens (a negative lens concave on the image side) 14 and a positive lens (a positive lens concave on the image side) 15 positioned in order from the object side. Consists of two lenses.
In Numerical Example 7-12, the first-b lens group G1b is composed of a negative single lens (negative single lens concave on the image side) 14 ′. The negative single lens 14 ′ is a double-sided spherical lens in Numerical Examples 7-9, 11, and 12, and in Numerical Example 10, the object-side surface is an aspherical surface.
The first-b lens group G1b is an image blur correction lens group (anti-vibration lens group) that corrects image blur by moving in the direction orthogonal to the optical axis and displacing the imaging position through all numerical examples 1-12. .

  The first c lens group G1c includes three lenses of a negative lens 16 and a positive lens 17, which are sequentially positioned from the object side, and a positive lens 18, in order from the object side, through all numerical examples 1-12. The positive lens 18 has an aspheric image side surface.

  The second lens group G2 is composed of three lenses, ie, a negative lens 21, a positive lens 22, and a negative lens 23, in order from the object side, through the numerical example 1-12.

  In the short-distance correction lens system with anti-shake function, set the displacement of the image point (eccentric sensitivity) appropriately with respect to the decentering amount of the image stabilization lens group (anti-vibration lens group). Therefore, it is required to maintain good optical performance at the time of anti-vibration driving by suppressing aberration fluctuations. In addition, it is necessary to select an appropriate glass material for the image blur correction lens group and to allocate an appropriate refractive power to the image blur correction lens group. Furthermore, in order to satisfactorily correct aberrations from an object at infinity to an object at a short distance, it is required to give an appropriate refractive power and focusing movement amount to the focus lens group.

  In this embodiment, the short-distance correction lens system includes a first lens group G1 having a positive refractive power and a second lens group G2 having a negative refractive power, and focusing from an object at infinity to a short-distance object is performed. The floating focus for moving the first lens group G1 and the second lens group G2 by different amounts of movement is essential. As a result, the focus mechanism system can be simplified and miniaturized, and excellent optical performance can be obtained by suppressing aberration fluctuations such as field curvature during close-up shooting.

  In the present embodiment, the first lens group G1 is divided into a first-a lens group G1a having a positive refractive power, a first-b lens group G1b having a negative refractive power, an aperture stop S, and a first-c lens group G1c having a positive refractive power. An image blur correction lens group (anti-vibration lens group) that corrects image blur by moving the first b lens group G1b located immediately before the aperture stop S in the direction orthogonal to the optical axis and changing the imaging position. ). Thereby, in the 1b lens group G1b, since the off-axis light beam passes near the optical axis, aberration variation due to decentering (particularly off-axis aberration variation such as field curvature and lateral chromatic aberration) can be suppressed to obtain excellent optical performance. Can do.

  As described above, in Numerical Example 1-6, the 1b lens group G1b includes the negative lens (negative lens concave on the image side) 14 and the positive lens (positive lens concave on the image side) sequentially from the object side. It consists of two lenses of 15 cemented lenses. As a result, aberration fluctuations due to decentration (particularly off-axis aberration fluctuations such as field curvature and lateral chromatic aberration) can be further reduced.

When the 1b lens group G1b is composed of two lenses, that is, a positive lens and a negative lens, it can be established from the object side in either positive or negative order or negative and positive order, but the 1b lens group G1b includes the 1a lens group. In order to allow the gently convergent light emitted from G1a to enter, the effective diameter on the object side tends to be higher than that on the image side in the 1b lens group G1b.
Therefore, if the lens is constructed in the order of positive and negative from the object side, the diameter of the positive lens on the object side increases and the volume increases and the weight of the first b lens group G1b increases. Therefore, the first b lens group G1b is prevented. The burden on the mechanism system for vibration driving (displacement) increases.
Therefore, in the present embodiment, the first lens group G1b is configured by a cemented lens of the negative lens 14 and the positive lens 15 that are sequentially arranged from the object side, so that the volume of the negative lens does not increase as much as the positive lens even if the diameter is increased. Therefore, the weight of the 1b lens group G1b is reduced, and the burden on the mechanism system that drives (displaces) the 1b lens group G1b is successfully reduced. Further, if the object-side surface of the first-b lens group G1b (negative lens 14) is a concave surface, spherical aberration and coma aberration can be corrected well. Further, the cemented surface of the negative lens 14 and the positive lens 15 of the first lens group G1b is convex on the object side (the negative lens 14 has a concave surface on the image side and the positive lens 15 has a convex surface on the object side). If so, the occurrence of spherical aberration can be suppressed.

Conditional expression (1) comprises the 1b lens group G1b as a cemented lens of a negative lens (a negative lens concave on the image side) 14 and a positive lens (a positive lens concave on the image side) 15 positioned in order from the object side. The Abbe number with respect to the d-line of the negative lens 14 is defined. By satisfying conditional expression (1), it is possible to suppress the variation in lateral chromatic aberration when the first-b lens group G1b is decentered.
When the lower limit of conditional expression (1) is exceeded, correction of lateral chromatic aberration at the time of decentering of the first lens group G1b becomes insufficient.

In the conditional expression (2), the first lens group G1b is composed of a cemented lens of a negative lens (a negative lens concave on the image side) 14 and a positive lens (a positive lens concave on the image side) 15 positioned in order from the object side. The difference between the Abbe numbers of the negative lens 14 and the positive lens 15 with respect to the d-line is defined. By satisfying conditional expression (2), it is possible to suppress the variation in lateral chromatic aberration when the 1b lens group G1b is decentered.
Since the 1b lens group G1b has a negative refractive power as a whole, in order to correct chromatic aberration in the 1b lens group G1b, the negative lens 14 is made of a material having a lower dispersion than the positive lens 15, and is negative. It is necessary to ensure an appropriate Abbe number difference that satisfies the conditional expression (2) between the lens 14 and the positive lens 15.
If the upper limit of conditional expression (2) is exceeded, the lateral chromatic aberration at the time of decentration of the first lens group G1b will be overcorrected.
If the lower limit of conditional expression (2) is exceeded, correction of lateral chromatic aberration at the time of decentering of the first lens group G1b will be insufficient.

Conditional expressions (3) and (4) indicate that the 1b lens group G1b is composed of a negative lens (a negative lens concave on the image side) 14 and a positive lens (a positive lens concave on the image side) 15 positioned in order from the object side. The refractive index with respect to the d-line that the negative lens 14 and the positive lens 15 should satisfy when configured with a cemented lens is defined. When the conditional expressions (3) and (4) are satisfied, the Petzval sum is appropriate, and not only the non-eccentricity but also the curvature of field can be corrected well.
Even if the upper limit of conditional expression (3) is exceeded or the lower limit of conditional expression (4) is exceeded, correction of each field curvature becomes difficult.

  As described above, the first-b lens group G1b includes the negative single lens (negative single lens concave on the image side) 14 ′ in Numerical Examples 7-12. As a result, the volume and weight of the 1b lens group G1b, which is the image blur correction lens group, can be reduced, and the burden on the mechanism system that drives (displaces) the first b lens group G1b can be reduced. Further, since the image-side surface of the first b lens group G1b (negative single lens 14 ′) is a concave surface, generation of spherical aberration can be suppressed. Further, if the object side surface of the first b lens group G1b (negative single lens 14 ′) is a concave surface, the coma aberration can be corrected well.

Conditional expression (5) defines the Abbe number with respect to the d-line that the negative single lens 14 ′ should satisfy when the 1b lens group G1b is composed of the negative single lens 14 ′. By using a lens of low dispersion material that satisfies the conditional expression (5) as the negative single lens 14 ′ that is an image blur correction lens, the magnification at the time of decentering of the 1b lens group G1b (negative single lens 14 ′) is obtained. Variation in chromatic aberration can be suppressed.
In a lens system similar to the Gauss type as in this embodiment, there is no point of correcting chromatic aberration of magnification with only a negative lens just before the aperture stop, and the negative lens just before the aperture stop has a small Abbe number (high dispersion) It has been conventional technical common sense to use materials. In this embodiment, such a conventional technical common sense is reviewed, and a conditional expression is used as the negative single lens 14 ′ so as to correct the lateral chromatic aberration at the time of image stabilization only by the negative single lens 14 ′ positioned immediately before the aperture stop S. A material having a large Abbe number (low dispersion) that satisfies (5) is used.
If the lower limit of conditional expression (5) is exceeded, correction of lateral chromatic aberration at the time of decentering of the first-b lens group G1b (negative single lens 14 ′) will be insufficient.

Conditional expression (6) defines the lateral magnification of the 1b lens group G1b at the time of infinite photographing. Conditional expression (7) defines the lateral magnification of the lens system (the first c lens group G1c and the second lens group G2) on the image side with respect to the first b lens group G1b at the time of photographing at infinity. That is, conditional expressions (6) and (7) define the decentering sensitivity, which is the amount of displacement of the image point with respect to the amount of decentering (displacement) of the 1b lens group G1b that is the image blur correction lens group.
Even if the upper limit of conditional expression (6) is exceeded or the lower limit of conditional expression (7) is exceeded, the decentration sensitivity decreases, and the decentering amount (displacement amount) of the first lens group G1b that is the image blur correction lens group. As a result, the burden on the mechanism system that drives (displaces) the first-b lens group G1b is increased. In addition, the response speed to image blur becomes low, and appropriate image blur correction cannot be performed.
Even if the lower limit of conditional expression (6) is exceeded or the upper limit of conditional expression (7) is exceeded, the refractive power of the first-b lens group G1b, which is the image blur correction lens group, increases too much, so Correction of decentration coma and the like becomes difficult.

Conditional expression (8) defines the ratio of the focal lengths of the first lens group G1 and the second lens group G2 which are the focus lens groups (the focal length of the first lens group G1 is a positive value and the second The focal length of the lens group G2 is a negative value). By satisfying the conditional expression (8), it is possible to appropriately set the moving amount (feeding amount) of the entire lens system accompanying focusing, and to satisfactorily correct aberrations during close-up shooting.
If the upper limit of conditional expression (8) is exceeded, correction of aberrations such as coma and field curvature during short-distance shooting will be insufficient.
If the lower limit of conditional expression (8) is exceeded, the moving amount (feeding amount) of the first lens group G1 accompanying focusing increases, which is not preferable in practice. Further, due to the eccentricity caused by the tilting of the first lens group G1 and the second lens group G2 as the focus lens group, the image surface tilting is likely to occur.

Conditional expression (9) defines the ratio of the moving amount (feeding amount) of the first lens group G1 and the second lens group G2 during focusing from an infinitely distant object to a close object. By satisfying conditional expression (9), it is possible to appropriately set the moving amount (feeding amount) of the entire lens system accompanying focusing, and to satisfactorily correct aberrations during close-up shooting.
If the upper limit of conditional expression (9) is exceeded, the amount of movement (feeding amount) of the second lens group G2 with respect to the first lens group G1 accompanying focusing increases, which is not practically preferable. Further, due to the eccentricity caused by the tilting of the first lens group G1 and the second lens group G2 as the focus lens group, the image surface tilting is likely to occur.
If the lower limit of conditional expression (9) is exceeded, aberration correction such as curvature of field during short-distance shooting will be insufficient.

Next, specific numerical examples will be shown. In the various aberration diagrams, lateral aberration diagrams and tables, d-line, g-line and C-line are aberrations for each wavelength, S is sagittal, M is meridional, FNO _. Is F-number, f is the focal length of the whole system, W Is the half field angle (°), Y is the image height, fB is the back focus, L is the total lens length, r is the radius of curvature, d is the lens thickness or lens spacing, N (d) is the refractive index with respect to the d line, and νd is d. Abbe's number LI with respect to the line is the amount of movement of the image blur correction lens group (anti-vibration lens group) in the direction perpendicular to the optical axis (LV) per 1 mm of movement in the direction perpendicular to the optical axis (eccentric sensitivity), “Ea "Means" × 10 ^-a ". The unit of length is [mm]. F-number, image height, back focus, total lens length, lens distance d that changes with focusing, amount of movement LV in the direction orthogonal to the optical axis of the image blur correction lens group, and amount of movement LI in the direction orthogonal to the optical axis of the image Are shown in the order of infinity shooting state-short-distance shooting state (shortest shooting state).
A rotationally symmetric aspherical surface is defined by
x = cy ² / [1+ [1- (1 + K) c ² y ² ] ^1/2 ] + A4y ⁴ + A6y ⁶ + A8y ⁸ + A10y ¹⁰ + A12y ¹² ...
(Where c is the curvature (1 / r), y is the height from the optical axis, K is the conic coefficient, A4, A6, A8,... Are the aspheric coefficients of each order)

[Numerical Example 1]
1 to 8 and Tables 1 to 4 show Numerical Example 1 of the short-range correction lens system according to the present invention. FIG. 1 is a lens configuration diagram in the state of photographing at infinity, FIG. 2 is a diagram showing aberrations thereof, and FIG. 3 is a diagram showing lateral aberrations thereof. FIG. 4 is a lens configuration diagram in the close-up shooting state, FIG. 5 is a diagram showing aberrations thereof, and FIG. 6 is a diagram showing its lateral aberrations. FIG. 7 is a lateral aberration diagram when anti-vibration driving is performed in an infinite distance photographing state, and FIG. 8 is a lateral aberration diagram when anti-vibration driving is performed in a short-distance photographing state. Table 1 shows surface data, Table 2 shows various data, Table 3 shows aspheric data, and Table 4 shows vibration-proof drive data.

  The short-distance correction lens system of Numerical Example 1 includes, 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.

  The first lens group G1, in order from the object side, includes a first-a lens group G1a having a positive refractive power, a first-b lens group G1b having a negative refractive power, an aperture stop S, and a first-c lens group G1c having a positive refractive power. Become.

  The first-a lens group G1a includes, in order from the object side, a negative meniscus lens 11 convex toward the object side, a positive meniscus lens 12 convex toward the object side, and a biconvex positive lens 13.

  The 1b lens group G1b is composed of a cemented lens of a biconcave negative lens (negative lens concave on the image side) 14 and a positive meniscus lens convex on the object side (positive lens concave on the image side) 15 sequentially from the object side. Become. The 1b lens group G1b is an image blur correction lens group (anti-vibration lens group) that corrects image blur by moving in the direction orthogonal to the optical axis and displacing the imaging position.

  The first c lens group G1c includes, in order from the object side, a cemented lens of a biconcave negative lens 16 and a biconvex positive lens 17 that are sequentially located from the object side, and a biconvex positive lens 18. The biconvex positive lens 18 has an aspheric image side surface.

  The second lens group G2 includes, in order from the object side, a negative meniscus lens 21, a biconvex positive lens 22, and a biconcave negative lens 23 that are convex on the object side.

(Table 1)
Surface data surface number rd N (d) νd
1 257.359 2.000 1.72916 54.7
2 39.866 15.590
3 59.386 6.620 1.83400 37.3
4 469.064 4.670
5 73.257 11.520 1.48749 70.4
6 -101.758 6.380
7 -386.499 1.450 1.67270 32.2
8 34.721 4.580 1.84666 23.8
9 74.798 6.130
10 stops ∞ 6.230
11 -45.091 2.000 1.75211 25.0
12 53.483 9.200 1.49700 81.6
13 -43.476 2.900
14 53.289 6.200 1.80450 39.6
15 * -139.359 d15
16 917.770 1.500 1.63980 34.6
17 42.729 5.220
18 120.465 5.600 1.80518 25.5
19 -70.785 4.170
20 -78.286 1.450 1.72342 38.0
21 144.240-
* Is a rotationally symmetric aspherical surface.
(Table 2)
Various data
Infinity shooting state Short-distance (-0.75x) shooting state
FNO. 2.85 4.66
f 90.84
W 20.8
Y 34.85 34.85
fB 66.65 110.84
L 175.74 226.24
d15 5.680 11.993
(Table 3)
Aspheric data surface number K A4
15 0.000 0.1690E-05
(Table 4)
Anti-vibration drive data
Infinity shooting state Short-distance (-0.75x) shooting state
f 90.84
LV 1.00 1.00
LI -0.74 -1.09

[Numerical Example 2]
9 to 16 and Tables 5 to 8 show Numerical Example 2 of the short distance correction lens system according to the present invention. FIG. 9 is a lens configuration diagram in the state of photographing at infinity, FIG. 10 is a diagram showing various aberrations thereof, and FIG. 11 is a diagram showing its lateral aberrations. 12 is a lens configuration diagram in the close-up shooting state, FIG. 13 is a diagram showing various aberrations thereof, and FIG. 14 is a diagram showing its lateral aberrations. FIG. 15 is a lateral aberration diagram when anti-vibration driving is performed in an infinite distance shooting state, and FIG. 16 is a lateral aberration diagram when anti-vibration driving is performed in a short-distance shooting state. Table 5 shows surface data, Table 6 shows various data, Table 7 shows aspherical data, and Table 8 shows vibration-proof drive data.

The lens configuration of Numerical Example 2 is the same as that of Numerical Example 1 except for the following points.
(1) The negative lens 21 of the second lens group G2 is a biconcave negative lens.

(Table 5)
Surface data surface number rd N (d) νd
1 473.951 2.000 1.69680 55.5
2 42.407 15.520
3 56.655 7.090 1.83400 37.3
4 617.022 4.080
5 81.434 8.290 1.49700 81.6
6 -137.766 6.930
7 -338.338 1.450 1.69895 30.0
8 31.510 5.320 1.80518 25.5
9 85.195 5.880
10 stops ∞ 7.050
11 -39.794 2.000 1.75520 27.5
12 67.154 9.200 1.49700 81.6
13 -37.583 1.400
14 50.849 6.040 1.80 101 40.9
15 * -174.666 d15
16 -4275.941 1.500 1.67270 32.2
17 44.710 5.160
18 137.335 5.350 1.80518 25.5
19 -73.119 5.110
20 -104.080 1.450 1.70154 41.2
21 145.257-
* Is a rotationally symmetric aspherical surface.
(Table 6)
Various data
Infinity shooting state Short-distance (-0.60x) shooting state
FNO. 2.87 4.32
f 90.45
W 21.0
Y 34.85 34.85
fB 66.76 101.86
L 173.26 213.84
d15 5.680 11.159
(Table 7)
Aspheric data surface number K A4 A6
15 0.000 0.1916E-05 -0.9666E-10
(Table 8)
Anti-vibration drive data
Infinity shooting state Short-distance (-0.60x) shooting state
f 90.45
LV 1.00 1.00
LI -0.75 -1.03

[Numerical Example 3]
17 to 24 and Tables 9 to 12 show Numerical Example 3 of the short distance correction lens system according to the present invention. FIG. 17 is a lens configuration diagram in the infinity shooting state, FIG. 18 is a diagram showing various aberrations thereof, and FIG. 19 is a lateral aberration diagram thereof. 20 is a lens configuration diagram in the close-up shooting state, FIG. 21 is a diagram showing various aberrations thereof, and FIG. 22 is a diagram showing its lateral aberrations. FIG. 23 is a lateral aberration diagram when anti-vibration driving is performed in an infinite distance photographing state, and FIG. 24 is a lateral aberration diagram when anti-vibration driving is performed in a short-distance photographing state. Table 9 shows surface data, Table 10 shows various data, Table 11 shows aspherical data, and Table 12 shows vibration-proof drive data.

  The lens configuration of Numerical Example 3 is the same as that of Numerical Example 1.

(Table 9)
Surface data surface number rd N (d) νd
1 396.791 2.000 1.74330 49.2
2 41.655 14.130
3 55.722 7.340 1.80450 39.6
4 925.902 4.330
5 79.513 6.800 1.49700 81.6
6 -130.947 8.610
7 -270.690 1.450 1.63980 34.6
8 34.890 4.440 1.84666 23.8
9 71.321 6.220
10 stops ∞ 6.750
11 -37.654 1.400 1.72825 28.3
12 64.373 9.500 1.49700 81.6
13 -36.125 1.510
14 56.221 5.740 1.80139 45.5
15 * -183.527 d15
16 224.032 1.500 1.67270 32.2
17 45.955 5.030
18 126.696 5.010 1.80518 25.5
19 -90.517 3.700
20 -107.635 1.450 1.70154 41.2
21 148.223-
* Is a rotationally symmetric aspherical surface.
(Table 10)
Various data
Infinity shooting state Short-distance (-0.75x) shooting state
FNO. 2.85 4.66
f 90.07
W 21.1
Y 34.85 34.85
fB 70.11 114.61
L 172.70 225.05
d15 5.680 13.533
(Table 11)
Aspheric data surface number K A4
15 0.000 0.1461E-05
(Table 12)
Anti-vibration drive data
Infinity shooting state Short-distance (-0.75x) shooting state
f 90.07
LV 1.00 1.00
LI -0.75 -1.10

[Numerical Example 4]
25 to 32 and Tables 13 to 16 show Numerical Example 4 of the short distance correction lens system according to the present invention. FIG. 25 is a lens configuration diagram in the infinity shooting state, FIG. 26 is a diagram showing its various aberrations, and FIG. 27 is a diagram showing its lateral aberration. FIG. 28 is a lens configuration diagram in the close-up shooting state, FIG. 29 is a diagram showing various aberrations thereof, and FIG. 30 is a diagram showing its lateral aberrations. FIG. 31 is a lateral aberration diagram when anti-vibration driving is performed in an infinite distance shooting state, and FIG. 32 is a lateral aberration diagram when anti-vibration driving is performed in a short-distance shooting state. Table 13 shows surface data, Table 14 shows various data, Table 15 shows aspherical data, and Table 16 shows image stabilization drive data.

  The lens configuration of Numerical Example 4 is the same as that of Numerical Example 1.

(Table 13)
Surface data surface number rd N (d) νd
1 313.004 2.000 1.83481 42.7
2 42.890 11.700
3 56.534 7.540 1.80610 33.3
4 1344.027 5.180
5 70.142 7.260 1.49700 81.6
6 -126.482 7.850
7 -253.610 1.450 1.63980 34.6
8 33.519 4.750 1.80518 25.5
9 74.839 6.130
10 stops ∞ 6.640
11 -38.315 1.400 1.72825 28.3
12 58.634 9.660 1.49700 81.6
13 -35.914 0.750
14 58.416 7.250 1.80610 40.7
15 * -183.734 d15
16 2478.431 1.550 1.63980 34.6
17 49.802 4.900
18 126.215 5.570 1.80610 33.3
19 -69.406 4.080
20 -65.521 1.450 1.56883 56.0
21 146.337-
* Is a rotationally symmetric aspherical surface.
(Table 14)
Various data
Infinity shooting state Short-distance (-0.50x) shooting state
FNO. 2.85 4.06
f 90.12
W 21.1
Y 34.85 34.85
fB 69.09 98.18
L 171.88 207.25
d15 5.680 11.958
(Table 15)
Aspheric data surface number K A4
15 0.000 0.1173E-05
(Table 16)
Anti-vibration drive data
Infinity shooting state Short-distance (-0.50x) shooting state
f 90.12
LV 1.00 1.00
LI -0.75 -1.01

[Numerical Example 5]
33 to 40 and Tables 17 to 20 show Numerical Example 5 of the short distance correction lens system according to the present invention. FIG. 33 is a lens configuration diagram in the infinity shooting state, FIG. 34 is a diagram showing its various aberrations, and FIG. 35 is a diagram showing its lateral aberration. FIG. 36 is a lens configuration diagram in the close-up shooting state, FIG. 37 is a diagram showing aberrations thereof, and FIG. 38 is a diagram showing its lateral aberrations. FIG. 39 is a lateral aberration diagram when anti-vibration driving is performed in an infinite distance shooting state, and FIG. 40 is a lateral aberration diagram when anti-vibration driving is performed in a short-distance shooting state. Table 17 shows surface data, Table 18 shows various data, Table 19 shows aspherical data, and Table 20 shows image stabilization drive data.

The lens configuration of Numerical Example 5 is the same as that of Numerical Example 1 except for the following points.
(1) The positive lens 12 of the 1a lens group G1a is a biconvex positive lens. The biconvex positive lens 12 has an aspheric object side surface.
(2) The negative lens 21 of the second lens group G2 is a plano-concave negative lens concave on the image side.

(Table 17)
Surface data surface number rd N (d) νd
1 2254.961 2.000 1.65 160 58.4
2 42.516 15.530
3 * 52.658 8.500 1.72916 54.7
4 -473.334 2.630
5 106.175 5.470 1.49700 81.6
6 -198.050 8.690
7 -238.065 1.450 1.59551 39.2
8 34.324 4.410 1.80518 25.5
9 67.445 6.900
10 stops ∞ 6.250
11 -43.265 1.400 1.71736 29.5
12 45.438 8.080 1.48749 70.4
13 -54.875 0.250
14 69.236 6.250 1.80139 45.5
15 * -80.649 d15
16 ∞ 1.500 1.53172 48.8
17 50.628 4.960
18 156.419 4.380 1.80610 33.3
19 -115.982 3.000
20 -427.329 1.450 1.72342 38.0
21 152.155-
* Is a rotationally symmetric aspherical surface.
(Table 18)
Various data
Infinity shooting state Short-distance (-0.50x) shooting state
FNO. 2.87 4.06
f 89.86
W 21.3
Y 34.85 34.85
fB 74.69 104.66
L 173.47 210.47
d15 5.680 12.710
(Table 19)
Aspheric data surface number K A4
3 0.000 -0.9260E-07
15 0.000 0.1535E-05
(Table 20)
Anti-vibration drive data
Infinity shooting state Short-distance (-0.50x) shooting state
f 89.86
LV 1.00 1.00
LI -0.75 -0.99

[Numerical Example 6]
FIGS. 41 to 48 and Tables 21 to 24 show Numerical Example 6 of the short-distance correction lens system according to the present invention. FIG. 41 is a lens configuration diagram in the infinity photographing state, FIG. 42 is a diagram showing various aberrations thereof, and FIG. 43 is a diagram showing its lateral aberrations. 44 is a lens configuration diagram in the close-up shooting state, FIG. 45 is a diagram showing various aberrations thereof, and FIG. 46 is a diagram showing its lateral aberrations. FIG. 47 is a lateral aberration diagram when anti-vibration driving is performed in an infinite distance shooting state, and FIG. 48 is a lateral aberration diagram when anti-vibration driving is performed in a short-distance shooting state. Table 21 shows surface data, Table 22 shows various data, Table 23 shows aspherical data, and Table 24 shows image stabilization drive data.

The lens configuration of Numerical Example 6 is the same as that of Numerical Example 1 except for the following points.
(1) The positive lens 12 of the 1a lens group G1a is a biconvex positive lens.
(2) The negative lens 21 of the second lens group G2 is a plano-concave negative lens concave on the image side.

(Table 21)
Surface data surface number rd N (d) νd
1 658.496 2.000 1.72916 54.7
2 43.844 18.040
3 57.724 7.370 1.80420 46.5
4 -8802.094 2.990
5 91.086 5.950 1.49700 81.6
6 -182.284 9.250
7 -269.188 1.450 1.64769 33.8
8 34.650 4.560 1.84666 23.8
9 72.895 6.200
10 stops ∞ 6.100
11 -48.574 1.400 1.71736 29.5
12 43.801 8.040 1.49700 81.6
13 -66.443 0.250
14 69.460 6.340 1.80139 45.5
15 * -83.906 d15
16 ∞ 1.500 1.56883 56.0
17 54.405 4.870
18 169.367 4.260 1.80610 33.3
19 -119.653 2.980
20 -506.702 1.450 1.63980 34.6
21 156.398-
* Is a rotationally symmetric aspherical surface.
(Table 22)
Various data
Infinity shooting state Short-distance (-0.50x) shooting state
FNO. 2.88 4.02
f 88.80
W 21.6
Y 34.85 34.85
fB 78.02 107.63
L 178.70 215.60
d15 5.680 12.969
(Table 23)
Aspheric data surface number K A4
15 0.000 0.1670E-05
(Table 24)
Anti-vibration drive data
Infinity shooting state Short-distance (-0.50x) shooting state
f 88.80
LV 1.00 1.00
LI -0.77 -1.00

[Numerical Example 7]
49 to 56 and Tables 25 to 28 show Numerical Example 7 of the short distance correction lens system according to the present invention. FIG. 49 is a lens configuration diagram in the infinity photographing state, FIG. 50 is a diagram showing various aberrations thereof, and FIG. 51 is a diagram showing its lateral aberration. FIG. 52 is a lens configuration diagram in the close-up shooting state, FIG. 53 is a diagram showing various aberrations thereof, and FIG. 54 is a lateral aberration diagram thereof. FIG. 55 is a lateral aberration diagram when anti-vibration driving is performed in an infinite distance shooting state, and FIG. 56 is a lateral aberration diagram when anti-vibration driving is performed in a short-distance shooting state. Table 25 shows surface data, Table 26 shows various data, Table 27 shows aspherical data, and Table 28 shows image stabilization drive data.

The lens configuration of Numerical Example 7 is the same as that of Numerical Example 1 except for the following points.
(1) The 1b lens group G1b is composed of a biconcave negative single lens (negative single lens concave on the image side) 14 '.
(2) The negative lens 16 of the first c lens group G1c is a plano-concave negative lens concave on the object side, and the positive lens 17 is a plano-convex positive lens convex on the image side.

(Table 25)
Surface data surface number rd N (d) νd
1 461.940 2.500 1.72000 50.3
2 41.142 15.540
3 62.000 7.490 1.80610 33.3
4 350.110 8.000
5 65.687 7.640 1.49700 81.6
6 -107.896 10.820
7 -358.740 2.000 1.80420 46.5
8 141.717 5.310
9 stop ∞ 8.040
10 -32.932 1.400 1.76182 26.6
11 ∞ 8.900 1.49700 81.6
12 -33.210 1.750
13 65.433 7.000 1.80139 45.5
14 * -144.406 d14
15 114.273 1.500 1.75520 27.5
16 47.735 5.700
17 80.998 5.750 1.80518 25.5
18 -92.183 4.500
19 -72.327 1.450 1.72342 38.0
20 74.154-
* Is a rotationally symmetric aspherical surface.
(Table 26)
Various data
Infinity shooting state Short-distance (-0.50x) shooting state
FNO. 2.88 4.00
f 89.19
W 21.2
Y 34.85 34.85
fB 66.77 91.68
L 177.74 209.25
d14 5.680 12.282
(Table 27)
Aspheric data surface number K A4
14 0.000 0.1550E-05
(Table 28)
Anti-vibration drive data
Infinity shooting state Short-distance (-0.50x) shooting state
f 89.19
LV 1.00 1.00
LI -0.77 -1.00

[Numerical Example 8]
57 to 64 and Tables 29 to 32 show Numerical Example 8 of the short distance correction lens system according to the present invention. FIG. 57 is a lens configuration diagram in the state of photographing at infinity, FIG. 58 is a diagram showing aberrations thereof, and FIG. 59 is a diagram showing its lateral aberrations. FIG. 60 is a lens configuration diagram in the close-up shooting state, FIG. 61 is a diagram showing various aberrations thereof, and FIG. 62 is a diagram showing its lateral aberrations. FIG. 63 is a lateral aberration diagram when the image stabilization drive is performed in the infinite distance shooting state, and FIG. 64 is a lateral aberration diagram when the image stabilization drive is performed in the short distance shooting state. Table 29 shows surface data, Table 30 shows various data, Table 31 shows aspherical data, and Table 32 shows image stabilization drive data.

The lens configuration of Numerical Example 8 is the same as that of Numerical Example 7 except for the following points.
(1) The negative lens 16 of the first c lens group G1c is a biconcave negative lens, and the positive lens 17 is a biconvex positive lens.

(Table 29)
Surface data surface number rd N (d) νd
1 1693.954 2.500 1.65844 50.8
2 41.055 13.160
3 56.198 7.490 1.80610 33.3
4 341.413 7.000
5 68.292 7.640 1.49700 81.6
6 -117.375 9.230
7 -333.385 2.000 1.77250 49.6
8 135.704 5.320
9 stops ∞ 7.350
10 -35.492 1.400 1.74077 27.8
11 168.532 8.900 1.49700 81.6
12 -34.595 3.340
13 58.068 6.000 1.80139 45.5
14 * -199.754 d14
15 113.267 1.500 1.75520 27.5
16 45.735 5.960
17 104.425 5.270 1.80518 25.5
18 -105.748 4.310
19 -86.718 1.450 1.54814 45.8
20 67.844-
* Is a rotationally symmetric aspherical surface.
(Table 30)
Various data
Infinity shooting state Short-distance (-0.75x) shooting state
FNO. 2.88 4.69
f 89.97
W 21.1
Y 34.85 34.85
fB 66.76 108.10
L 172.26 222.07
d14 5.680 14.148
(Table 31)
Aspheric data surface number K A4
14 0.000 0.1564E-05
(Table 32)
Anti-vibration drive data
Infinity shooting state Short-distance (-0.75x) shooting state
f 89.97
LV 1.00 1.00
LI -0.75 -1.10

[Numerical Example 9]
65 to 72 and Tables 33 to 36 show Numerical Example 9 of the short distance correction lens system according to the present invention. FIG. 65 is a lens configuration diagram in the infinity shooting state, FIG. 66 is a diagram showing its various aberrations, and FIG. 67 is a diagram showing its lateral aberration. 68 is a lens configuration diagram in the close-up shooting state, FIG. 69 is a diagram showing various aberrations thereof, and FIG. 70 is a lateral aberration diagram thereof. 71 is a lateral aberration diagram when the image stabilization drive is performed in the infinite distance shooting state, and FIG. 72 is a lateral aberration diagram when the image stabilization drive is performed in the short distance shooting state. Table 33 shows surface data, Table 34 shows various data, Table 35 shows aspherical data, and Table 36 shows image stabilization drive data.

The lens configuration of Numerical Example 9 is the same as that of Numerical Example 8 except for the following points.
(1) The negative lens 21 of the second lens group G2 is a biconcave negative lens.

(Table 33)
Surface data surface number rd N (d) νd
1 752.090 2.500 1.74400 44.9
2 43.606 12.880
3 58.619 7.490 1.80610 33.3
4 859.851 8.850
5 68.831 7.080 1.49700 81.6
6 -126.284 9.620
7 -254.859 2.000 1.63854 55.5
8 115.686 5.510
9 stop ∞ 7.230
10 -36.167 1.400 1.76182 26.6
11 143.880 8.000 1.49700 81.6
12 -35.608 0.250
13 63.687 7.000 1.80610 40.7
14 * -124.847 d14
15 -887.272 1.500 1.59551 39.2
16 50.795 6.570
17 245.346 5.340 1.80610 33.3
18 -60.009 4.330
19 -52.174 1.450 1.51742 52.2
20 207.658-
* Is a rotationally symmetric aspherical surface.
(Table 34)
Various data
Infinity shooting state Short distance (-0.70x) shooting state
FNO. 2.85 4.46
f 90.20
W 21.1
Y 34.85 34.85
fB 68.70 106.80
L 173.38 219.85
d14 5.680 14.044
(Table 35)
Aspheric data surface number K A4
14 0.000 0.1516E-05
(Table 36)
Anti-vibration drive data
Infinity shooting state Short distance (-0.70x) shooting state
f 90.20
LV 1.00 1.00
LI -0.75 -1.07

[Numerical Example 10]
73 to 80 and Tables 37 to 40 show Numerical Example 10 of the short distance correction lens system according to the present invention. FIG. 73 is a lens configuration diagram in the infinity shooting state, FIG. 74 is a diagram showing various aberrations thereof, and FIG. 75 is a diagram showing its lateral aberrations. 76 is a lens configuration diagram in the close-up shooting state, FIG. 77 is a diagram showing various aberrations thereof, and FIG. 78 is a diagram showing its lateral aberration. FIG. 79 is a lateral aberration diagram when anti-vibration driving is performed in an infinite distance shooting state, and FIG. 80 is a lateral aberration diagram when anti-vibration driving is performed in a short-distance shooting state. Table 37 shows surface data, Table 38 shows various data, Table 39 shows aspherical data, and Table 40 shows image stabilization drive data.

The lens configuration of Numerical Example 10 is the same as that of Numerical Example 8 except for the following points.
(1) The object-side surface of the biconcave negative single lens 14 ′ of the 1b lens group G1b is aspheric.

(Table 37)
Surface data surface number rd N (d) νd
1 801.150 2.500 1.66755 41.9
2 43.839 17.638
3 57.889 7.490 1.80610 33.3
4 1118.478 3.944
5 82.838 7.640 1.49700 81.6
6 -171.499 10.144
7 * -197.079 2.000 1.56883 56.0
8 110.909 5.560
9 stops ∞ 7.484
10 -33.934 1.400 1.80518 25.5
11 447.167 8.500 1.49700 81.6
12 -32.827 0.250
13 74.739 5.572 1.80101 40.9
14 * -133.789 d14
15 210.515 1.500 1.76182 26.6
16 61.029 4.786
17 210.371 4.990 1.80518 25.5
18 -71.924 4.434
19 -59.278 1.450 1.56732 42.8
20 235.864-
* Is a rotationally symmetric aspherical surface.
(Table 38)
Various data
Infinity shooting state Short-distance (-0.50x) shooting state
FNO. 2.87 4.03
f 89.78
W 21.3
Y 34.85 34.85
fB 71.81 98.43
L 174.77 209.79
d14 5.680 14.085
(Table 39)
Aspheric data surface number K A4
7 0.000 0.2067E-06
14 0.000 0.1399E-05
(Table 40)
Anti-vibration drive data
Infinity shooting state Short-distance (-0.50x) shooting state
f 89.78
LV 1.00 1.00
LI -0.75 -0.98

[Numerical Example 11]
81 to 88 and Tables 41 to 44 show Numerical Example 11 of the short distance correction lens system according to the present invention. 81 is a lens configuration diagram in the infinity photographing state, FIG. 82 is a diagram showing various aberrations thereof, and FIG. 83 is a diagram showing its lateral aberrations. 84 is a lens configuration diagram in the short-distance photographing state, FIG. 85 is a diagram showing various aberrations thereof, and FIG. 86 is a diagram showing its lateral aberrations. FIG. 87 is a lateral aberration diagram when anti-vibration driving is performed in an infinite distance shooting state, and FIG. 88 is a lateral aberration diagram when anti-vibration driving is performed in a short-distance shooting state. Table 41 shows surface data, Table 42 shows various data, Table 43 shows aspherical data, and Table 44 shows image stabilization drive data.

The lens configuration of Numerical Example 11 is the same as that of Numerical Example 9 except for the following points.
(1) The positive lens 22 of the second lens group G2 is a positive meniscus lens convex on the image side.
(2) The negative lens 23 of the second lens group G2 is a negative meniscus lens convex to the image side.

(Table 41)
Surface data surface number rd N (d) νd
1 6222.464 2.500 1.69680 55.5
2 51.279 21.250
3 61.446 6.790 1.80420 46.5
4 1046.985 4.300
5 78.658 5.790 1.59282 68.6
6 -476.802 13.170
7 -270.658 2.000 1.58913 61.2
8 99.474 5.710
9 stops ∞ 6.250
10 -43.405 1.400 1.76182 26.6
11 101.960 7.140 1.49700 81.6
12 -43.751 0.250
13 67.056 5.290 1.80610 40.7
14 * -135.096 d14
15 -192.704 1.500 1.56732 42.8
16 63.121 5.760
17 -310.957 4.620 1.80610 33.3
18 -51.980 4.290
19 -47.283 1.450 1.51742 52.2
20 -116.387-
* Is a rotationally symmetric aspherical surface.
(Table 42)
Various data
Infinity shooting state Short-distance (-0.60x) shooting state
FNO. 2.88 4.27
f 89.49
W 21.3
Y 34.85 34.85
fB 71.60 101.79
L 176.74 217.27
d14 5.680 16.017
(Table 43)
Aspheric data surface number K A4
14 0.000 0.1612E-05
(Table 44)
Anti-vibration drive data
Infinity shooting state Short-distance (-0.60x) shooting state
f 89.49
LV 1.00 1.00
LI -0.75 -1.03

[Numerical Example 12]
89 to 96 and Tables 45 to 48 show Numerical Example 12 of the short distance correction lens system according to the present invention. FIG. 89 is a lens configuration diagram in the infinity shooting state, FIG. 90 is a diagram showing various aberrations thereof, and FIG. 91 is a diagram showing its lateral aberrations. FIG. 92 is a lens configuration diagram in the close-up shooting state, FIG. 93 is a diagram showing various aberrations thereof, and FIG. 94 is a lateral aberration diagram thereof. FIG. 95 is a lateral aberration diagram when anti-vibration driving is performed in an infinite distance shooting state, and FIG. 96 is a lateral aberration diagram when anti-vibration driving is performed in a short-distance shooting state. Table 45 shows surface data, Table 46 shows various data, Table 47 shows aspherical data, and Table 48 shows image stabilization drive data.

The lens configuration of Numerical Example 12 is the same as that of Numerical Example 9 except for the following points.
(1) The negative lens 23 of the second lens group G2 is a negative meniscus lens convex toward the image side.

(Table 45)
Surface data surface number rd N (d) νd
1 1351.161 2.500 1.63854 55.5
2 47.061 21.200
3 65.007 6.650 1.80420 46.5
4 334.047 4.210
5 65.288 6.010 1.59282 68.6
6 -259.126 12.780
7 -319.084 2.000 1.61800 63.4
8 99.906 5.690
9 stops ∞ 5.850
10 -49.185 1.400 1.80610 33.3
11 60.987 7.990 1.49700 81.6
12 -40.930 0.250
13 61.777 5.180 1.80139 45.5
14 * -191.077 d14
15 -114.378 1.500 1.54814 45.8
16 63.756 5.080
17 911.791 5.510 1.80420 46.5
18 -49.104 4.220
19 -45.079 1.450 1.48749 70.4
20 -267.360-
* Is a rotationally symmetric aspherical surface.
(Table 46)
Various data
Infinity shooting state Short-distance (-0.50x) shooting state
FNO. 2.88 4.07
f 88.55
W 21.6
Y 34.85 34.85
fB 71.71 99.08
L 176.86 212.41
d14 5.680 13.857
(Table 47)
Aspheric data surface number K A4
14 0.000 0.1013E-05
(Table 48)
Anti-vibration drive data
Infinity shooting state Short-distance (-0.50x) shooting state
f 88.55
LV 1.00 1.00
LI -0.75 -1.03

Table 49 shows values for the conditional expressions of the numerical examples.
(Table 49)
Example 1 Example 2 Example 3
Conditional expression (1) 32.17 30.05 34.57
Conditional expression (2) 8.39 4.45 10.79
Conditional expression (3) 1.673 1.699 1.640
Conditional expression (4) 1.847 1.805 1.847
Conditional expression (5) − − −
Conditional expression (6) 2.51 2.70 2.90
Conditional expression (7) 0.49 0.44 0.39
Conditional expression (8) 1.93 2.03 2.40
Conditional expression (9) 0.875 0.865 0.850
Example 4 Example 5 Example 6
Conditional expression (1) 34.57 39.22 33.84
Conditional expression (2) 9.27 13.62 10.06
Conditional expression (3) 1.640 1.596 1.648
Conditional expression (4) 1.805 1.805 1.847
Conditional expression (5) − − −
Conditional expression (6) 2.98 3.00 3.17
Conditional expression (7) 0.38 0.38 0.35
Conditional expression (8) 2.57 3.45 3.89
Conditional expression (9) 0.822 0.810 0.802
Example 7 Example 8 Example 9
Conditional expression (1)---
Conditional expression (2) − − −
Conditional expression (3) − − −
Conditional expression (4) − − −
Conditional expression (5) 46.50 49.62 55.45
Conditional expression (6) 3.11 3.00 2.90
Conditional expression (7) 0.36 0.38 0.40
Conditional expression (8) 1.95 2.10 2.39
Conditional expression (9) 0.791 0.830 0.820
Example 10 Example 11 Example 12
Conditional expression (1)---
Conditional expression (2) − − −
Conditional expression (3) − − −
Conditional expression (4) − − −
Conditional expression (5) 56.04 61.25 63.39
Conditional expression (6) 2.81 2.66 2.51
Conditional expression (7) 0.42 0.45 0.49
Conditional expression (8) 2.95 3.47 3.86
Conditional expression (9) 0.760 0.745 0.770

  As apparent from Table 49, Numerical Example 1 to Numerical Example 6 satisfy the conditional expressions (1) to (4) and (6) to (9), and Numerical Example 7 to Numerical Example. 12 satisfies the conditional expressions (5) to (9). Further, as is apparent from the various aberration diagrams, the various aberrations are corrected relatively well.

G1 First lens group G1a with positive refractive power 1a lens group 11 with positive refractive power 11 Negative lens 12 Positive lens 13 Positive lens G1b 1b lens group with negative refractive power (image blur correction lens group, anti-vibration lens group) )
14 Negative lens (negative lens concave on the image side)
14 'negative single lens (negative single lens concave on the image side)
15 Positive lens (positive lens concave on the image side)
G1c 1st lens group 16 having positive refractive power 16 Negative lens 17 Positive lens 18 Positive lens G2 2nd lens group 21 having negative refractive power Negative lens 22 Positive lens 23 Negative lens S Aperture stop I Image surface

Claims (7)

A first lens group having a positive refractive power and a second lens group having a negative refractive power in order from the object side, and in focusing from an object at infinity to a short distance object, the first lens group and the second lens group In a short-range correction lens system in which each moves toward the object side with a different amount of movement,
The first lens group is composed of, in order from the object side, a first-a lens group having a positive refractive power, a first-b lens group having a negative refractive power, an aperture stop, and a first-c lens group having a positive refractive power;
The first-b lens group includes a cemented lens of a negative lens that is concave on the image side and a positive lens that is concave on the image side, in order from the object side; and that the following conditional expression (2) is satisfied:
A short-range correction lens system characterized by
_{(2) 0 <νd 1bn -νd} 1bp <20
However,
νd _1bn : Abbe number for the d-line of the negative lens in the 1b lens group,
νd _1bp : Abbe number with respect to d-line of the positive lens in the 1b lens group. The short-range correction lens system according to claim 1,
A short-distance correction lens system that satisfies the following conditional expression (1).
(1) νd _1bn > 30
However,
νd _1bn : Abbe number for the d-line of the negative lens in the 1b lens group. In the short distance correction lens system according to claim 1 or 2,
A short-distance correction lens system that satisfies the following conditional expressions (3) and (4).
(3) nd _1bn <1.7
(4) nd _1bp > 1.8
However,
nd _1bn : refractive index with respect to d-line of the negative lens in the 1b lens group,
nd _1bp : Refractive index with respect to d-line of the positive lens in the 1b lens group. A first lens group having a positive refractive power and a second lens group having a negative refractive power in order from the object side, and in focusing from an object at infinity to a short distance object, the first lens group and the second lens group In a short-range correction lens system in which each moves toward the object side with a different amount of movement,
The first lens group is composed of, in order from the object side, a first-a lens group having a positive refractive power, a first-b lens group having a negative refractive power, an aperture stop, and a first-c lens group having a positive refractive power;
The 1b lens group is composed of a negative single lens concave on the image side; and satisfies the following conditional expression (5):
A short-range correction lens system characterized by
(5) νd _1b > 45
However,
νd _1b : Abbe number for the d-line of the negative single lens in the 1b lens group. In the short distance correction lens system according to any one of claims 1 to 4,
A short-distance correction lens system that satisfies the following conditional expressions (6) and (7).
(6) 2.5 <β _1b <3.2
(7) 0.35 <β _R <0.50
However,
β _1b : lateral magnification of the 1b lens group at infinity shooting,
β _R : lateral magnification of the lens system on the image side from the 1b lens group at the time of infinity shooting. The short-range correction lens system according to any one of claims 1 to 5,
A short-distance correction lens system that satisfies the following conditional expression (8):
(8) 1.9 <| f2 / f1 | <3.9 (f2 <0)
However,
f1: the focal length of the first lens group,
f2: Focal length of the second lens group. The short-range correction lens system according to any one of claims 1 to 6,
A short-distance correction lens system that satisfies the following conditional expression (9):
(9) 0.74 <Δd2 / Δd1 <0.88
However,
Δd1: Amount of movement of the first lens unit during focusing from an object at infinity to a near object;
Δd2: The amount of movement of the second lens group during focusing from an object at infinity to a near object.

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