JP5545531B2 - Photographic lens, optical apparatus having the photographic lens, and method of manufacturing the photographic lens - Google Patents

Description

  The present invention relates to a photographic lens, an optical apparatus having the photographic lens, and a method for manufacturing the photographic lens.

  Conventionally, as a photographic lens having an anti-vibration optical system, means for correcting camera shake or the like by moving some lenses in a direction perpendicular to the optical axis is known. For example, in Patent Document 1, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a negative refraction in order from the object side. A fourth lens group having power, and for a short-distance object, the second lens group is moved to the image side along the optical axis for focusing, and the third lens group is set in a direction orthogonal to the optical axis. An optical system that corrects an image position by moving it is disclosed. In general, a telephoto lens is reduced in size by applying a tele ratio to the focal length. In recent years, it is common to mount a motor. For this reason, it is required to reduce the focusing lens group and to move the movement amount.

JP 2009-1625 A

  However, as the focal length increases, the diameter of the focusing lens group increases and the amount of movement increases. In general, in an anti-vibration optical system, the movement amount is added to the outer diameter of the anti-vibration lens group in addition to the thickness of the hardware holding frame, and an actuator is arranged on the outer side, so the mechanism is considerably larger than the effective diameter of the lens. turn into. In addition, a photographing lens having a larger focal length requires a moving amount on the image plane, and the moving amount of the image stabilizing lens group tends to be large.

  In the optical system described in Patent Document 1, the ratio of the amount of movement of the image stabilizing lens group to the amount of movement of the image on the imaging plane is 1.7 at the maximum. Then, a substantially parallel light beam enters the third lens group, and an image formed by the third lens group is relayed by the fourth lens group. In such an optical system, if the ratio of the amount of movement of the image stabilizing lens group to the amount of image movement on the imaging surface is increased, the third lens group becomes a bright optical system with a small focal length, and no image stabilization is performed. This affects the correction of the imaging performance of the state. On the other hand, in a photographic lens having a longer focal length than the optical system described in Patent Document 1, the amount of movement on the required image plane is further increased, which increases the amount of movement of the anti-vibration lens group and impairs commerciality. It will be.

  The present invention has been made in view of such problems, and has a photographic lens capable of obtaining an effective anti-vibration performance while reducing the amount of movement of the anti-vibration lens group and achieving downsizing. It is an object of the present invention to provide an optical apparatus and a method for manufacturing a photographing lens.

In order to solve the above-described problems, a photographic lens according to the present invention has, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a positive refractive power. The fourth lens group is substantially composed of a third lens group having a negative refractive power and a fourth lens group having a negative refractive power. When focusing from infinity to a short-distance object point, the second lens group has an optical axis. The third lens group is configured to move so as to have a component in a direction orthogonal to the optical axis, and the magnification of the third lens group at the time of focusing on infinity is set. β3, the magnification of the fourth lens group is β4, and the air distance from the most image side surface of the first lens group to the most object side surface of the second lens group at the time of focusing on infinity is d12, In the lens group, the widest air among the air spaces between the lenses constituting the first lens group. When the interval is d , the following formula 1.75 <| (β3-1) × β4 | <2.50
1.00 <d / d12 <3.50
Satisfy the conditions.

The photographing lens according to the present invention includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power. The lens unit consists essentially of four lens units with a fourth lens unit having negative refractive power, and the second lens unit moves to the image side along the optical axis when focusing from infinity to a short-distance object point. The first lens group includes at least two lenses having negative refractive power, and the third lens group is configured to move so as to have a component in a direction orthogonal to the optical axis. When the magnification of the third lens unit at the time of focusing on infinity is β3 and the magnification of the fourth lens unit is β4,
1.75 <| (β3-1) × β4 | <2.50
Satisfy the conditions.

Further, in such a photographing lens, the air distance from the most image-side surface of the first lens unit to the most object-side surface of the second lens unit at the time of focusing on infinity is d12. Of the air spaces between the lenses constituting the first lens group, where d is the widest air space, the following formula 1.00 <d / d12 <3.50
It is preferable to satisfy the following conditions.

Further, in such a photographing lens, in the first lens group, the lens located on the object side of the widest air interval among the air intervals between the lenses constituting the first lens group is the front group, and the widest When the lens located on the image side from the air interval is the rear group, the focal length of the front group is f11, and the focal length of the rear group is f12, the following expression 0.30 <f11 / f12 <1.50
It is preferable to satisfy the following conditions.

In such a photographing lens, the first lens group is a lens having a positive refractive power, and when the refractive index with respect to the d-line of each medium of the lens is nd and the Abbe number is νd, Formula nd <1.50
νd> 80
It is preferable to have three or more lenses that satisfy the above condition.

  In such a photographic lens, it is preferable that the third lens group includes at least one lens having a positive refractive power and at least one lens having a negative refractive power.

  Further, in such a photographing lens, it is preferable that all lens surfaces are constituted by spherical surfaces.

  An optical apparatus according to the present invention includes any one of the above-described photographing lenses.

Further, in the manufacturing method of the photographing lens according to the present invention, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens having a positive refractive power. A method of manufacturing a photographic lens comprising substantially four lens groups of a lens group and a fourth lens group having a negative refractive power, wherein the second lens is focused upon focusing from infinity to a short-distance object point. The group is arranged to move toward the image side along the optical axis, and the third lens group is arranged to move so as to have a component in a direction orthogonal to the optical axis, and the third lens group at the time of focusing on infinity. Is β3, the magnification of the fourth lens group is β4, and the air distance from the most image side surface of the first lens group to the most object side surface of the second lens group at the time of focusing on infinity is d12. In the first lens group, among the air intervals between the lenses constituting the first lens group, Where d is a wide air gap , the following formula 1.75 <| (β3-1) × β4 | <2.50
1.00 <d / d12 <3.50
Arrange to satisfy the conditions.

  When the photographic lens, the optical apparatus having the photographic lens, and the manufacturing method of the photographic lens according to the present invention are configured as described above, the movement amount of the anti-vibration lens group is reduced, and it is effective while achieving downsizing. Anti-vibration performance can be obtained.

It is sectional drawing which shows the structure of the imaging lens by 1st Example. FIG. 4A is a diagram illustrating various aberrations of the first example, and FIG. 5A is a diagram illustrating various aberrations in an infinitely photographing state, and FIG. It is a coma aberration diagram. It is sectional drawing which shows the structure of the imaging lens by 2nd Example. FIG. 5A is a diagram illustrating various aberrations of the second example, and FIG. 9A is a diagram illustrating various aberrations in an infinite photographing state, and FIG. It is a coma aberration diagram. It is sectional drawing which shows the structure of the photographic lens by 3rd Example. FIG. 7A is a diagram illustrating various aberrations of the third example, and FIG. 9A is a diagram illustrating various aberrations in an infinite photographing state, and FIG. It is a coma aberration diagram. 1 is a cross-sectional view of a digital single-lens reflex camera equipped with a photographing lens according to the present embodiment. It is a flowchart for demonstrating the manufacturing method of the imaging lens which concerns on this embodiment.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the photographic lens SL according to this embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a positive A third lens group G3 having a refractive power and a fourth lens group G4 having a negative refractive power are configured.

  In the photographing lens SL according to the present embodiment, the second lens group G2 moves to the image side along the optical axis when focusing from infinity to a short-distance object point, and functions as a focusing lens group. This focusing lens group can be applied to autofocus, and is also suitable for driving a motor for autofocus (such as an ultrasonic motor).

  In the photographing lens SL according to the present embodiment, at least a part of the third lens group G3 moves so as to have a component in a direction orthogonal to the optical axis, or rotates in an in-plane direction including the optical axis ( It functions as an anti-vibration lens group that corrects image blur caused by camera shake.

  Now, conditions for configuring such a photographing lens SL will be described. In the photographic lens SL according to this embodiment, when the magnification of the third lens group G3 at the time of focusing on infinity is β3 and the magnification of the fourth lens group G4 is β4, the following conditional expression (1) is satisfied. Is desirable.

1.75 <| (β3-1) × β4 | <2.50 (1)

  Conditional expression (1) is a conditional expression for defining an appropriate anti-vibration coefficient. Exceeding the upper limit value of conditional expression (1) is not preferable because it becomes difficult to correct various aberrations such as spherical aberration. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (1) to 2.30. In order to further secure the effect of the present embodiment, it is more preferable to set the upper limit of conditional expression (1) to 2.10. On the other hand, if the lower limit value of conditional expression (1) is not reached, it becomes difficult to correct fluctuations in decentration coma and field curvature due to decentration. In addition, the shift amount increases, the diameter of the unit that holds the image stabilizing lens group increases, and the optical system increases in size, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (1) to 1.85. In order to further secure the effect of the present embodiment, it is more preferable to set the lower limit of conditional expression (1) to 1.95.

  In addition, in the first lens group G1, the photographic lens SL of the present embodiment has a lens located on the object side of the widest air interval among the air intervals between the lenses constituting the first lens group G1. When the lens located on the image side from the widest air space is the rear group G1R, the focal length of the front group G1F is f11, and the focal length of the rear group G1R is f12, the following conditional expression (2) is satisfied: It is desirable to do.

0.30 <f11 / f12 <1.50 (2)

  Conditional expression (2) is a conditional expression for defining the ratio between the focal length of the front group G1F and the focal length of the rear group G1R in the first lens group G1. Exceeding the upper limit of conditional expression (2) is not preferable because spherical aberration at the time of focusing on infinity deteriorates. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (2) to 1.10. On the other hand, if the lower limit value of conditional expression (2) is not reached, the aberration fluctuation at the time of focusing on a short-distance object point becomes large, and particularly the axial chromatic aberration is deteriorated. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (2) to 0.50.

In the photographic lens SL according to the present embodiment, the air distance from the most image side surface of the first lens group G1 to the most object side surface of the second lens group G2 at the time of focusing on infinity is d12, In the first lens group G1, it is desirable to satisfy the following conditional expression (3), where d is the widest air distance among the air distances between the lenses constituting the first lens group G1.
1.00 <d / d12 <3.50 (3)

  Conditional expression (3) indicates that the air gap D between the lenses constituting the first lens group G1 and the most object of the second lens group G2 from the most image-side surface of the first lens group G1 when focusing on infinity. It is a conditional expression for prescribing the ratio with the air gap d12 to the side surface. Exceeding the upper limit of conditional expression (3) is not preferable because spherical aberration at the time of focusing on infinity increases. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (3) to 3.00. On the other hand, if the lower limit of conditional expression (3) is not reached, spherical aberration at the time of focusing at a short distance increases, and the first lens group G1 becomes large, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (3) to 1.30.

  In the photographic lens SL according to the present embodiment, the first lens group G1 is a lens having a positive refractive power, and the refractive index with respect to the d-line of each medium of the lens is nd, and the Abbe number is νd. Then, it is desirable to have three or more lenses that satisfy the following conditional expressions (4) and (5).

nd <1.50 (4)
νd> 80 (5)

  Each of the lenses having positive refractive power constituting the first lens group G1 is made of anomalous dispersion glass. Conditional expression (4) is a conditional expression for defining the refractive index with respect to the d-line of each medium of a lens having a positive refractive power. If the lower limit of conditional expression (4) is not reached, it is not preferable because the secondary spectrum cannot be corrected.

  Conditional expression (5) is a conditional expression for defining the Abbe number of each medium of a lens having a positive refractive power. If the lower limit of conditional expression (5) is not reached, it is not preferable because the secondary spectrum cannot be corrected.

  In the photographic lens SL according to this embodiment, it is desirable that the first lens group has at least two lenses having negative refractive power. With this configuration, axial chromatic aberration can be favorably corrected.

  In the photographing lens SL according to this embodiment, it is desirable that the third lens group includes at least one lens having a positive refractive power and at least one lens having a negative refractive power. With this configuration, it is possible to reduce fluctuations in decentration coma and field curvature due to decentration during image stabilization.

  In addition, it is desirable that all the lens surfaces of the photographic lens SL according to the present embodiment are spherical surfaces. Thus, it is preferable that the lens surface is spherical because lens processing and assembly adjustment are facilitated, and deterioration of optical performance due to errors in processing and assembly adjustment is prevented. Further, even when the image plane is deviated, it is preferable because there is little deterioration in drawing performance.

  The lens surface may be formed as a flat surface, and in this case, the same effect as that obtained when the lens surface is a spherical surface can be obtained. Alternatively, the lens surface may be formed as an aspheric surface. When the lens surface is an aspheric surface, the aspheric surface is an aspheric surface by grinding, a glass mold aspheric surface made of glass with an aspheric shape, or a composite aspheric surface made of resin with an aspheric shape on the glass surface. Any aspherical surface may be used. The lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

  FIG. 7 shows a schematic cross-sectional view of a digital single-lens reflex camera 1 (hereinafter simply referred to as a camera) as an optical apparatus including the above-described photographing lens SL. In this camera 1, light from an object (subject) (not shown) is collected by the taking lens 2 (shooting lens SL) and imaged on the focusing screen 4 via the quick return mirror 3. The light imaged on the focusing screen 4 is reflected a plurality of times in the pentaprism 5 and guided to the eyepiece lens 6. Thus, the photographer can observe the object (subject) image as an erect image through the eyepiece 6.

  Further, when a release button (not shown) is pressed by the photographer, the quick return mirror 3 is retracted out of the optical path, and light of an object (subject) (not shown) condensed by the photographing lens 2 is captured on the image sensor 7. Form an image. Thereby, the light from the object (subject) is captured by the image sensor 7 and recorded as an object (subject) image in a memory (not shown). In this way, the photographer can shoot an object (subject) with the camera 1. Note that the camera 1 shown in FIG. 7 may be one that holds the photographic lens SL in a detachable manner, or may be molded integrally with the photographic lens SL. The camera 1 may be a so-called single-lens reflex camera or a compact camera without a quick return mirror or the like.

  The contents described below can be appropriately adopted as long as the optical characteristics are not impaired.

In the above description and the embodiments described below, the four-group configuration is shown, but the present invention can also be applied to other group configurations such as the fifth group and the sixth group. Further, a configuration in which a lens or a lens group is added on the object side or a configuration in which a lens or a lens group is added on the most image side may be used. The lens group indicates a part having at least one lens separated by an air interval that changes at the time of focusing , or a part that moves so as to have a component in a direction orthogonal to the optical axis .

  The aperture stop S is preferably arranged in the vicinity of the third lens group G3, but the role of the aperture stop S may be substituted by a lens frame without providing a member as an aperture stop.

  Further, each lens surface may be provided with an antireflection film having a high transmittance in a wide wavelength region in order to reduce flare and ghost and achieve high optical performance with high contrast.

  In the photographic lens SL of the present embodiment, it is preferable that the first lens group G1 has three positive lens components and one negative lens component. In the first lens group G1, it is preferable to dispose the lens components in order of positive / negative / positive in order from the object side with an air gap interposed therebetween. In the photographic lens SL of the present embodiment, it is preferable that the second lens group G2 has two negative lens components.

  In the photographing lens SL of the present embodiment, it is preferable that the third lens group G3 has at least two positive lens components and one negative lens component. In the third lens group G3, it is preferable to arrange the lens components in order of positive and negative from the object side with an air gap interposed therebetween. However, for example, in order from the object side, a combination of a positive and negative lens with a positive refractive power as a whole and a positive lens with an air gap, or in order from the object side, a positive lens and a negative positive A combination with a lens having a positive refractive power as a whole is also effective. In the photographic lens SL of the present embodiment, it is preferable that the fourth lens group G4 has two positive lens components and two negative lens components. Further, it is preferable that the first lens component and the second lens component are cemented in the order of negative and positive and have positive refractive power as a whole. In the fourth lens group G4, it is preferable that lens components are arranged in order of positive (junction lens) negative / positive in order from the object side with an air gap interposed therebetween.

  In addition, in order to explain the present invention in an easy-to-understand manner, the configuration requirements of the embodiment have been described, but it goes without saying that the present invention is not limited to this.

  Hereinafter, an outline of the first manufacturing method of the photographic lens SL of the present embodiment will be described with reference to FIG. First, each lens is arranged and a lens group is prepared (step S100). Specifically, in the present embodiment, for example, as the front group G1F, a biconvex lens L11, a biconvex lens L12, and a biconcave lens L13 are arranged in order from the object side, and as the rear group G1R, the object side in order from the object side. A cemented lens composed of a negative meniscus lens L14 having a convex surface facing the lens and a positive meniscus lens L15 having a convex surface facing the object side is arranged as the first lens group G1, and the negative meniscus having the convex surface facing the object side in order from the object side. A lens L21 and a cemented lens of a positive meniscus lens L22 having a convex surface facing the image side and a biconcave lens L23 are arranged to form the second lens group G2, and in order from the object side, the biconvex lens L31 and the convex surface are directed to the image side. The negative meniscus lens L32 and the positive meniscus lens L33 having a convex surface facing the object side are arranged as a third lens group G3. 41 a cemented lens of a biconvex lens L42, biconvex lens L43, and a fourth lens group G4 are arranged a positive meniscus lens L44 having a convex surface directed toward the object side. The lens groups prepared in this way are arranged to manufacture the photographing lens SL.

  Then, the second lens group G2 is arranged so as to move toward the image side along the optical axis when focusing from infinity to a short-distance object point (step S200). Further, the third lens group G3 is arranged to move so as to have a component in a direction orthogonal to the optical axis (step S300). Further, when the magnification of the third lens group G3 at the time of focusing on infinity is β3 and the magnification of the fourth lens group G4 is β4, the lens is arranged so as to satisfy the above-described conditional expression (1) (step S400).

  Embodiments of the present invention will be described below with reference to the accompanying drawings. 1, 3, and 5 are cross-sectional views illustrating the configuration of the photographic lens SL (SL1 to SL3) according to each embodiment. As shown in these figures, the photographic lens SL of each example includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a positive The third lens group G3 having refractive power and the fourth lens group G4 having negative refractive power are configured. The first lens group G1 includes a front group G1F and a rear group G1R.

  In addition, a low-pass filter P1 is provided between the fourth lens group G4 and the image plane I for cutting a spatial frequency higher than the limit resolution of a solid-state imaging device such as a CCD disposed on the image plane I. Yes.

  In such a photographing lens SL, the second lens group G2 moves to the image side along the optical axis when focusing from infinity to a short-distance object point. The aperture stop S is disposed between the second lens group G2 and the third lens group G3, and moves together with the third lens group G3 when focusing from infinity to a short-distance object point. Further, camera shake correction (anti-vibration) is performed by moving the third lens group G3 so as to have a component in a direction orthogonal to the optical axis.

[First embodiment]
FIG. 1 is a diagram illustrating a configuration of a photographic lens SL1 according to the first example. In the photographic lens SL1 of FIG. 1, the front group G1F of the first lens group G1 is composed of a biconvex lens L11, a biconvex lens L12, and a biconcave lens L13 in order from the object side, and the rear group of the first lens group G1. G1R includes, in order from the object side, a cemented lens of a negative meniscus lens L14 having a convex surface facing the object side and a positive meniscus lens L15 having a convex surface facing the object side. The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface facing the object side, and a cemented lens of a positive meniscus lens L22 having a convex surface facing the image side and a biconcave lens L23. . The third lens group G3 includes, in order from the object side, a biconvex lens L31, a negative meniscus lens L32 having a convex surface directed toward the image side, and a positive meniscus lens L33 having a convex surface directed toward the object side. The fourth lens group G4 includes, in order from the object side, a cemented lens of a biconcave lens L41 and a biconvex lens L42, a biconvex lens L43, and a positive meniscus lens L44 having a convex surface facing the object side.

  Table 1 below lists values of specifications of the photographing lens SL1 according to the first example. In Table 1, f represents the focal length, and β represents the photographing magnification. Furthermore, the surface number is the order of the lens surfaces from the object side along the direction of travel of the light beam, the surface interval is the distance on the optical axis from each optical surface to the next optical surface, and the refractive index and Abbe number are each The value for the d-line (λ = 587.6 nm) is shown. The total length represents the distance on the optical axis from the first surface of the lens surface to the image plane I when focusing on infinity. Here, “mm” is generally used for the focal length, the radius of curvature, the surface interval, and other length units listed in all the following specifications, but the optical system is proportionally enlarged or reduced. However, the same optical performance can be obtained, and the present invention is not limited to this. The radius of curvature of 0.00000 indicates a plane, and the refractive index of air of 1.0000 is omitted. The description of these symbols and the description of the specification table are the same in the following embodiments.

(Table 1)
f = 800.00
FNo = 5.61

Surface number Curvature radius Surface spacing Abbe number Refractive index
1 197.3776 22.0000 82.52 1.497820
2 -1470.7246 2.6400
3 194.5741 22.0000 82.52 1.497820
4 -607.7156 2.5000
5 -573.0998 6.0000 49.61 1.772499
6 255.5150 129.0361
7 96.6534 4.8000 49.61 1.772499
8 62.8138 16.5000 82.52 1.497820
9 298.7352 (d1)
10 523.4388 3.5100 44.78 1.743997
11 87.8081 3.6783
12 -1545.5347 6.5000 23.78 1.846660
13 -53.9911 3.5100 40.11 1.762001
14 99.2249 (d2)
15 0.0000 5.0000 (Aperture stop S)
16 70.1137 9.0000 58.89 1.518230
17 -64.8425 2.0000
18 -60.3328 3.0000 27.51 1.755200
19 -160.1209 1.5000
20 170.3585 4.5000 70.45 1.487490
21 665.2843 (d3)
22 -1747.9398 2.3000 44.79 1.744000
23 35.7523 8.0000 35.74 1.625880
24 -53.8679 3.3536
25 -52.0265 2.2000 44.79 1.744000
26 82.1246 0.5000
27 66.0696 4.5000 48.87 1.531720
28 1093.1559 5.0000
29 0.0000 2.0000 64.19 1.516798
30 0.0000 118.3228

  In the first embodiment, the axial air gap d0 between the object and the first lens group G1, the axial air gap d1 between the first lens group G1 and the second lens group G2, the second lens group G2 and the third lens. The axial air distance d2 between the group G3 and the axial air distance d3 between the third lens group G3 and the fourth lens group G4 change during focusing. In the following Table 2, infinite focus state, first intermediate shooting distance state (shooting magnification β = −0.033 times state), second intermediate shooting distance state (shooting magnification β = −0.050 times state), In addition, a variable interval in the close-up shooting distance state (shooting magnification β = −0.153 times state) is shown.

(Table 2)
Infinity First intermediate shooting distance Second intermediate shooting distance Closest shooting distance
f or β ∞ -0.033 times -0.050 times -0.153 times
d0 ∞ 24188.0670 16162.7470 5412.3602
d1 58.75062 62.04619 63.68051 73.91086
d2 20.91405 17.61849 15.98417 5.75382
d3 14.29757 14.29778 14.35292 14.25488

  Table 3 below shows values corresponding to the conditional expressions of the photographic lens SL1 according to the first example. In addition, although description of the code | symbol in this Table 3 is shown below, this code | symbol description is the same also in a subsequent Example. In Table 3, β3 is the magnification of the third lens group G3 when focusing on infinity, β4 is the magnification of the fourth lens group G4, f11 is the focal length of the front group G1F of the first lens group G1, and f12. Is the focal length of the rear group G1R of the first lens group G1, and d12 is the air from the most image side surface of the first lens group G1 to the most object side surface of the second lens group G2 when focusing on infinity. The distance, d is the air distance between the front group G1F and the rear group G1R, f is the focal length of the entire system, nd and νd are d of each medium of the lens having the positive refractive power of the first lens group G1. Refractive index and Abbe number for the line are shown respectively.

(Table 3)
(1) | (β3-1) × β4 | = 1.965
(2) f11 / f12 = 0.940
(3) d / d12 = 2.196
(4) nd = 1.497820 (L11, L12, L15)
(5) νd = 82.52 (L11, L12, L15)

  FIG. 2 shows aberration diagrams of the first example. That is, FIG. 2A is an aberration diagram in the infinite focus state, and FIG. 2B is a coma aberration diagram when blur correction is performed with respect to 0.3 ° rotational blur in the infinity shooting state. . In each aberration diagram, F is the F number, Y is the image height, D is the aberration curve for the d-line (λ = 587.6 nm), and G is the aberration curve for the g-line (λ = 435.8 nm). Show. In the aberration diagrams showing astigmatism, the solid line shows the sagittal image plane, and the broken line shows the meridional image plane. The description of this aberration diagram is the same in the following examples. As is apparent from the respective aberration diagrams, in the first example, it is understood that various aberrations are favorably corrected from the infinity state to the close-up shooting state, and the imaging performance is excellent.

[Second Embodiment]
FIG. 3 is a diagram illustrating a configuration of the photographic lens SL2 according to the second example. 3, the front group G1F of the first lens group G1 is composed of a biconvex lens L11, a biconvex lens L12, and a biconcave lens L13 in this order from the object side, and the rear group of the first lens group G1. G1R includes, in order from the object side, a cemented lens of a negative meniscus lens L14 having a convex surface facing the object side and a positive meniscus lens L15 having a convex surface facing the object side. The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface facing the object side, a positive meniscus lens L22 having a convex surface facing the image side, and a negative meniscus lens L23 having a convex surface facing the image side. This is composed of a cemented lens. The third lens group G3 includes, in order from the object side, a biconvex lens L31, a negative meniscus lens L32 having a convex surface directed toward the image side, and a biconvex lens L33. The fourth lens group G4 includes, in order from the object side, a cemented lens of a biconcave lens L41 and a biconvex lens L42, a biconcave lens L43, and a biconvex lens L44.

  Table 4 below lists values of specifications of the second embodiment.

(Table 4)
f = 800.00
FNo = 5.62

Surface number Curvature radius Surface spacing Abbe number Refractive index
1 200.5897 22.0000 64.19 1.456000
2 -871.2735 2.6400 91.38
3 172.4889 22.5000 91.38 1.456000
4 -754.1893 2.5000
5 -678.9597 6.0000 49.61 1.772499
6 312.9898 114.6712
7 112.1450 4.8000 49.61 1.772499
8 64.8229 16.5000 82.52 1.497820
9 388.6057 (d1)
10 999.7482 3.5100 44.78 1.743997
11 61.2071 4.5000
12 -115.7864 6.5000 23.78 1.846660
13 -39.3777 3.5100 44.79 1.744000
14 -405.8991 (d2)
15 0.0000 5.0000 (Aperture stop S)
16 104.4111 9.0000 52.32 1.517420
17 -53.5187 2.0000
18 -50.2515 3.0000 35.04 1.749500
19 3239.0007 1.0000
20 134.8987 5.5000 52.32 1.517420
21 -96.6053 (d3)
22 -274.0655 2.3000 44.78 1.743997
23 40.2812 8.0000 42.72 1.567320
24 -43.1114 1.1283
25 -48.0592 2.2000 44.78 1.743997
26 111.3256 10.9555
27 112.7046 4.5000 42.72 1.567320
28 -136.9183 5.0000
29 0.0000 2.0000 64.19 1.516798
30 0.0000 102.0767

  In the second embodiment, the axial air gap d0 between the object and the first lens group G1, the axial air gap d1 between the first lens group G1 and the second lens group G2, the second lens group G2 and the third lens. The axial air distance d2 between the group G3 and the axial air distance d3 between the third lens group G3 and the fourth lens group G4 change during focusing. In the following Table 5, the infinite focus state, the first intermediate shooting distance state (shooting magnification β = −0.033 times state), the second intermediate shooting distance state (shooting magnification β = −0.050 times state), In addition, a variable interval in the close-up shooting distance state (shooting magnification β = −0.127 times state) is shown.

(Table 5)
Infinity First intermediate shooting distance Second intermediate shooting distance Closest shooting distance
f or β ∞ -0.033 times -0.050 times -0.127 times
d0 ∞ 24173.8330 16171.4600 6500.3078
d1 53.88118 57.00296 58.55699 65.80160
d2 12.20954 9.08776 7.53373 0.28912
d3 40.30983 40.31178 40.31760 40.30983

  Table 6 below shows values corresponding to the conditional expressions of the photographic lens SL2 according to the second example.

(Table 6)
(1) | (β3-1) × β4 | = 1.800
(2) f11 / f12 = 0.545
(3) d / d12 = 2.128
(4) nd = 1.456000 (L11, L12), 1.497820 (L15)
(5) νd = 64.19 (L11), 91.38 (L12), 82.52 (L15)

  FIG. 4 shows aberration diagrams of the second example. That is, FIG. 4A is an aberration diagram in the infinite focus state, and FIG. 4B is a coma aberration diagram when blur correction is performed with respect to a 0.3 ° rotational blur in the infinity shooting state. . As is apparent from the respective aberration diagrams, in the second example, it is understood that various aberrations are favorably corrected from the infinity state to the close-up shooting state, and the imaging performance is excellent.

[Third embodiment]
FIG. 5 is a diagram illustrating a configuration of the photographic lens SL3 according to the third example. In the photographic lens SL3 of FIG. 5, the front group G1F of the first lens group G1 is composed of a biconvex lens L11, a biconvex lens L12, and a biconcave lens L13 in order from the object side, and the rear group of the first lens group G1. G1R includes, in order from the object side, a cemented lens of a negative meniscus lens L14 having a convex surface facing the object side and a positive meniscus lens L15 having a convex surface facing the object side. The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface facing the object side, and a cemented lens of a positive meniscus lens L22 having a convex surface facing the image side and a biconcave lens L23. . The third lens group G3 includes, in order from the object side, a biconvex lens L31, a negative meniscus lens L32 having a convex surface directed toward the image side, and a positive meniscus lens L33 having a convex surface directed toward the object side. The fourth lens group G4 includes, in order from the object side, a cemented lens of a biconcave lens L41 and a biconvex lens L42, a biconcave lens L43, and a positive meniscus lens L44 having a convex surface facing the object side.

  Table 7 below lists values of specifications of the third example.

(Table 7)
f = 800.00
FNo = 5.63

Surface number Curvature radius Surface spacing Abbe number Refractive index
1 197.3776 22.0000 82.52 1.497820
2 -1470.7246 2.6400
3 194.5741 22.0000 82.52 1.497820
4 -607.7156 2.5000
5 -573.0998 6.0000 49.61 1.772499
6 255.5150 129.0361
7 96.6534 4.8000 49.61 1.772499
8 62.8138 16.5000 82.52 1.497820
9 298.7352 (d1)
10 523.4388 3.5100 44.78 1.743997
11 87.8081 3.6783
12 -1545.5347 6.5000 23.78 1.846660
13 -53.9911 3.5100 40.11 1.762001
14 99.2249 (d2)
15 0.0000 5.0000 (Aperture stop S)
16 70.1137 9.0000 58.89 1.518230
17 -64.8425 2.0000
18 -60.3328 3.0000 27.51 1.755200
19 -160.1209 1.5000
20 170.3585 4.5000 70.45 1.487490
21 665.2843 (d3)
22 -1747.9398 2.3000 44.79 1.744000
23 35.7523 8.0000 35.74 1.625880
24 -53.8679 3.3536
25 -52.0265 2.2000 44.79 1.744000
26 82.1246 0.5000
27 66.0696 4.5000 48.87 1.531720
28 1093.1559 5.0000
29 0.0000 2.0000 64.19 1.516798
30 0.0000 118.2991

  In this third example, the axial air gap d0 between the object and the first lens group G1, the axial air gap d1 between the first lens group G1 and the second lens group G2, the second lens group G2 and the third lens. The axial air distance d2 between the group G3 and the axial air distance d3 between the third lens group G3 and the fourth lens group G4 change during focusing. In the following Table 8, infinite focus state, first intermediate shooting distance state (shooting magnification β = −0.033 times state), second intermediate shooting distance state (shooting magnification β = −0.050 times state), In addition, a variable interval in the close-up shooting distance state (shooting magnification β = −0.154 times state) is shown.

(Table 8)
Infinity First intermediate shooting distance Second intermediate shooting distance Closest shooting distance
f or β ∞ -0.033 times -0.050 times -0.154 times
d0 ∞ 24188.0670 16162.7470 5412.3602
d1 58.75062 62.04619 63.68051 73.91086
d2 20.91405 17.61849 15.98417 5.75382
d3 14.29757 14.29778 14.35292 14.25488

  Table 9 below shows values corresponding to the conditional expressions of the photographic lens SL3 according to the third example.

(Table 9)
(1) | (β3-1) × β4 | = 1.965
(2) f11 / f12 = 0.940
(3) d / d12 = 2.196
(4) nd = 1.497820 (L11, L12, L15)
(5) νd = 82.52 (L11, L12, L15)

  FIG. 6 shows various aberration diagrams of the third example. That is, FIG. 6A is an aberration diagram in the infinite focus state, and FIG. 6B is a coma aberration diagram when blur correction is performed with respect to a 0.3 ° rotational blur in the infinity shooting state. . As is apparent from the respective aberration diagrams, in the third example, it is understood that various aberrations are favorably corrected from the infinity state to the close-up shooting state, and the imaging performance is excellent.

SL (SL1 to SL3) Shooting lens G1 First lens group G1F Front group G1R Rear group G2 Second lens group G3 Third lens group G4 Fourth lens group S Aperture stop 1 Electronic still camera (optical equipment)

Claims (9)

From the object side,
A first lens group having a positive refractive power;
A second lens group having negative refractive power;
A third lens group having positive refractive power;
Substantially consisting of four lens groups with a fourth lens group having negative refractive power,
The second lens group is configured to move to the image side along the optical axis when focusing from infinity to a short-distance object point,
The third lens group is configured to move so as to have a component in a direction orthogonal to the optical axis,
The magnification of the third lens group at the time of focusing on infinity is β3, the magnification of the fourth lens group is β4, and the second lens from the most image side surface of the first lens group at the time of focusing on infinity. When the air space to the most object side surface of the group is d12, and the air space between the lenses constituting the first lens group in the first lens group is d, the widest air space is d. 1.75 <| (β3-1) × β4 | <2.50
1.00 <d / d12 <3.50
Shooting lens that satisfies the above conditions. From the object side,
A first lens group having a positive refractive power;
A second lens group having negative refractive power;
A third lens group having positive refractive power;
Substantially consisting of four lens groups with a fourth lens group having negative refractive power,
The second lens group is configured to move to the image side along the optical axis when focusing from infinity to a short-distance object point,
The first lens group has at least two lenses having negative refractive power,
The third lens group is configured to move so as to have a component in a direction orthogonal to the optical axis,
When the magnification of the third lens group at the time of focusing on infinity is β3 and the magnification of the fourth lens group is β4, the following expression 1.75 <| (β3-1) × β4 | <2.50
Shooting lens that satisfies the above conditions. The air distance from the most image side surface of the first lens group to the most object side surface of the second lens group at the time of focusing on infinity is d12, and the first lens group in the first lens group Where d is the widest air interval among the air intervals between the lenses constituting the following formula: 1.00 <d / d12 <3.50
The photographic lens according to claim 2 , which satisfies the following condition. In the first lens group, among the air intervals between the lenses constituting the first lens group, a lens positioned on the object side with respect to the widest air interval is set as a front group, and is positioned on the image side with respect to the widest air interval. When the lens is the rear group, the focal length of the front group is f11, and the focal length of the rear group is f12, the following expression 0.30 <f11 / f12 <1.50
The photographic lens according to any one of claims 1 to 3, which satisfies the following condition. The first lens group is a lens having a positive refractive power, and when the refractive index for the d-line of each medium of the lens is nd and the Abbe number is νd, the following formula nd <1.50.
νd> 80
A lens that satisfies the condition more than three, the imaging lens according to any one of claims 1-4.   6. The photographing according to claim 1, wherein the third lens group includes at least one lens having a positive refractive power and at least one lens having a negative refractive power. lens.   The taking lens according to any one of claims 1 to 6, wherein all lens surfaces are formed of spherical surfaces.   An optical apparatus having the photographing lens according to any one of claims 1 to 7. In order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens having a negative refractive power A method of manufacturing a photographic lens comprising substantially four lens groups with a group ,
When focusing from infinity to a short distance object point, the second lens group is arranged to move to the image side along the optical axis,
The third lens group is arranged to move so as to have a component in a direction orthogonal to the optical axis,
The magnification of the third lens group at the time of focusing on infinity is β3, the magnification of the fourth lens group is β4, and the second lens from the most image side surface of the first lens group at the time of focusing on infinity. When the air space to the most object side surface of the group is d12, and the air space between the lenses constituting the first lens group in the first lens group is d, the widest air space is d. 1.75 <| (β3-1) × β4 | <2.50
1.00 <d / d12 <3.50
The manufacturing method of the photographic lens arrange | positioned so that these conditions may be satisfied.

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