JP5561256B2 - OPTICAL SYSTEM, OPTICAL DEVICE HAVING THE OPTICAL SYSTEM, AND METHOD FOR PRODUCING OPTICAL SYSTEM - Google Patents

Description

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

  Conventionally, a retrofocus lens preceded by a lens group having a negative refractive power is known as an optical system with a wide angle of view that can secure a back focus enough to be used in a single lens reflex camera or a digital camera even with a short focal length. . This lens type has been proposed with a large aperture of about F1.4 (see, for example, Patent Document 1). In recent years, not only aberration performance but also ghost and flare requirements, which are one of the factors that impair optical performance, have become increasingly demanding for such optical systems. Higher performance is also required for the prevention film, and multilayer film design technology and multilayer film formation technology continue to advance to meet the demand (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 11-30743 JP 2000-356704 A

  However, the conventional optical system with a wide angle of view has a problem that the aberration correction at the time of image stabilization is not sufficient when the image stabilization mechanism is employed. At the same time, the optical surface in such an optical system also has a problem that reflected light that becomes ghost or flare is easily generated.

  The present invention has been made in view of such a problem, and further reduces ghosts and flares, and has an optical system with higher performance and excellent vibration isolation performance, an optical apparatus having the optical system, and an optical system. An object is to provide a manufacturing method.

In order to solve the above problems, an optical system according to the present invention includes:
From the object side,
A first lens group;
A second lens group having negative refractive power;
The third lens group having a positive refractive power substantially consists of three lens groups ,
An antireflection film is provided on at least one of the optical surfaces of the first lens group and the second lens group, and the antireflection film includes at least one layer formed using a wet process,
The first lens group is fixed in the optical axis direction with respect to the image plane,
The second lens group is composed of a cemented negative lens movably arranged to have a component in a direction orthogonal to the optical axis ,
The distance on the optical axis from the lens surface closest to the image plane of the second lens group at infinity focusing to the paraxial image plane of the entire system is Σdvr, and the focal length of the entire system at infinity focusing is where f is
3.07 ≦ Σdvr / f <5.00
An optical system characterized by satisfying the following conditions is provided.
The present invention also provides:
From the object side,
A first lens group;
A second lens group having negative refractive power;
The third lens group having a positive refractive power substantially consists of three lens groups,
An antireflection film is provided on at least one of the optical surfaces of the first lens group and the second lens group, and the antireflection film includes at least one layer formed using a wet process,
The first lens group is fixed in the optical axis direction with respect to the image plane,
The second lens group is composed of a cemented negative lens movably arranged to have a component in a direction orthogonal to the optical axis,
The distance on the optical axis from the lens surface closest to the image plane of the second lens group at infinity focusing to the paraxial image plane of the entire system is Σdvr, and the focal length of the entire system at infinity focusing is When the lateral magnification of the second lens group at the time of focusing on infinity is βvr and the lateral magnification of the third lens group at the time of focusing on infinity is β3,
2.00 <Σdvr / f <5.00
0.15 <| (1-βvr) × β3 | <0.50
An optical system characterized by satisfying the following conditions is provided.
The optical system according to the present invention is
From the object side,
A first lens group;
A second lens group having negative refractive power;
The third lens group having a positive refractive power substantially consists of three lens groups,
An antireflection film is provided on at least one of the optical surfaces of the first lens group and the second lens group, and the antireflection film includes at least one layer formed using a wet process,
The first lens group is fixed in the optical axis direction with respect to the image plane,
The second lens group is composed of a cemented negative lens movably arranged so as to have a component in a direction orthogonal to the optical axis,
The distance on the optical axis from the lens surface closest to the image plane of the second lens group at infinity focusing to the paraxial image plane of the entire system is Σdvr, and the focal length of the entire system at infinity focusing is f, and the focal length of the second lens group is f2.
When
2.00 <Σdvr / f <5.00
−0.35 <f / f2 <−0.07
An optical system characterized by satisfying the following conditions is provided.
The optical system according to the present invention is
From the object side,
A first lens group;
A second lens group having negative refractive power;
The third lens group having a positive refractive power substantially consists of three lens groups,
An antireflection film is provided on at least one of the optical surfaces of the first lens group and the second lens group, and the antireflection film includes at least one layer formed using a wet process,
The first lens group is fixed in the optical axis direction with respect to the image plane,
The second lens group is composed of a cemented negative lens, a negative lens, and a positive lens in order from an object side that is movably disposed so as to have a component in a direction orthogonal to the optical axis.
The distance on the optical axis from the lens surface closest to the image plane of the second lens group at infinity focusing to the paraxial image plane of the entire system is Σdvr, and the focal length of the entire system at infinity focusing is where f is
2.00 <Σdvr / f <5.00
An optical system characterized by satisfying the following conditions is provided.

  An optical apparatus according to the present invention includes any one of the above-described optical systems that forms an image of an object on a predetermined image plane.

In addition, the method for manufacturing an optical system according to the present invention includes:
In order from the object side, an optical system manufacturing method comprising substantially three lenses by a first lens group, a second lens group having a negative refractive power, and a third lens group having a positive refractive power. There,
An antireflection film is provided on at least one of the optical surfaces of the first lens group and the second lens group, and the antireflection film includes at least one layer formed by using a wet process,
The first lens group is disposed so as to be fixed in the optical axis direction with respect to the image plane,
The second lens group is composed of a cemented negative lens, and the second lens group is arranged to move so as to have a component in a direction substantially perpendicular to the optical axis,
The distance on the optical axis from the lens surface closest to the image plane of the second lens group at infinity focusing to the paraxial image plane of the entire system is Σdvr, and the focal length of the entire system at infinity focusing is where f is
3.07 ≦ Σdvr / f <5.00
An optical system manufacturing method is provided, wherein the optical system is arranged so as to satisfy the above condition.

  ADVANTAGE OF THE INVENTION According to this invention, a ghost and a flare can be reduced more and the optical system excellent in the anti-vibration performance, the optical apparatus provided with this optical system, and the manufacturing method of an optical system can be provided.

It is sectional drawing which shows the lens structure of the optical system which concerns on 1st Example. FIG. 4A is a diagram illustrating various aberrations according to the first example, in which FIG. 3A is a diagram illustrating various aberrations in an infinite focus state, and FIG. 4B is a blur correction for 0.70 ° rotational blur in the infinite focus state. It is a coma aberration figure when it went. FIG. 6A is a diagram illustrating various aberrations according to the first example, and FIG. 9A is a diagram illustrating various aberrations in an intermediate shooting distance state, and FIG. 9B is a camera shake correction for 0.70 ° rotation blur in the intermediate shooting distance state. It is a coma aberration figure at the time. It is sectional drawing which shows the lens structure of the optical system which concerns on 1st Example, Comprising: The figure explaining an example of a mode that the incident light ray reflects in the 1st reflected light generation surface and the 2nd reflected light generation surface It is. It is sectional drawing which shows the lens structure of the optical system which concerns on 2nd Example. FIG. 6A is a diagram illustrating various aberrations according to the second example, in which FIG. 9A is a diagram illustrating various aberrations in an infinite focus state, and FIG. 9B is a blur correction for 0.70 ° rotational blur in an infinite photographing state. FIG. FIG. 5A is a diagram illustrating various aberrations according to the second example, in which FIG. 9A is a diagram illustrating aberrations in the intermediate shooting distance state, and FIG. 9B is a camera shake correction for 0.70 ° rotation blur in the intermediate shooting distance state. It is a coma aberration figure at the time. It is sectional drawing which shows the lens structure of the optical system which concerns on 3rd Example. FIG. 7A is a diagram illustrating various aberrations according to the third example, and FIG. 9A is a diagram illustrating various aberrations in an infinite focus state, and FIG. 9B is a blur correction for 0.70 ° rotational blur in an infinite photographing state. FIG. FIG. 6A is a diagram illustrating various aberrations according to the third example, in which FIG. 9A is a diagram illustrating various aberrations in an intermediate shooting distance state, and FIG. 9B is a blur correction for 0.70 ° rotation blur in the intermediate shooting distance state. It is a coma aberration figure at the time. It is sectional drawing which shows the lens structure of the optical system which concerns on 4th Example. FIG. 9A is a diagram illustrating various aberrations according to the fourth example, in which FIG. 10A is a diagram illustrating aberrations in an infinite focus state, and FIG. 10B is a camera shake correction for 0.70 ° rotation blur in an infinite photographing state. FIG. FIG. 9A is a diagram illustrating various aberrations according to the fourth example, in which FIG. 9A is a diagram illustrating various aberrations in an intermediate shooting distance state, and FIG. 9B is a blur correction for 0.70 ° rotation blur in the intermediate shooting distance state. It is a coma aberration figure at the time. It is sectional drawing which shows the lens structure of the optical system which concerns on 5th Example. FIG. 9A is a diagram illustrating various aberrations according to the fifth example, in which FIG. 10A is a diagram illustrating various aberrations in an infinite focus state, and FIG. 10B is a blur correction for 0.70 ° rotational blur in the infinity shooting state. FIG. FIG. 7A is a diagram illustrating various aberrations according to the fifth example, in which FIG. 9A illustrates various aberrations in an intermediate shooting distance state, and FIG. 10B illustrates shake correction with respect to 0.70 ° rotation blur in the intermediate shooting distance state. It is a coma aberration figure at the time. It is sectional drawing which shows the lens structure of the optical system which concerns on 6th Example. FIG. 9A is a diagram illustrating various aberrations according to the sixth example, in which FIG. 10A is a diagram illustrating various aberrations in an infinitely focused state, and FIG. FIG. FIG. 6A is a diagram illustrating various aberrations according to the sixth example, in which FIG. 9A illustrates various aberrations in an intermediate shooting distance state, and FIG. 10B illustrates shake correction for 0.70 ° rotation blur in the intermediate shooting distance state. It is a coma aberration figure at the time. It is sectional drawing which shows the lens structure of the optical system which concerns on 7th Example. FIG. 10A is a diagram illustrating various aberrations according to Example 7, wherein FIG. 10A is a diagram illustrating aberrations in an infinite focus state, and FIG. 10B is a camera shake correction for 0.70 ° rotational blur in an infinite state photographing state. FIG. FIG. 9A is a diagram illustrating various aberrations according to the seventh example. FIG. 10A is a diagram illustrating aberrations at an intermediate shooting distance state, and FIG. 9B is a camera shake correction for 0.70 ° rotation blur at the intermediate shooting distance state. It is a coma aberration figure at the time. It is sectional drawing which shows the lens structure of the optical system which concerns on an 8th Example. FIG. 10A is a diagram illustrating various aberrations according to Example 8, wherein FIG. 10A is a diagram illustrating various aberrations in the infinite focus state, and FIG. 10B is a blur correction for 0.70 ° rotational blur in the infinity shooting state. FIG. FIG. 10A is a diagram illustrating various aberrations according to Example 8, wherein FIG. 10A is a diagram illustrating aberrations at an intermediate shooting distance state, and FIG. 9B is a blur correction for 0.70 ° rotational blur in the intermediate shooting distance state. It is a coma aberration figure at the time. 1 is a cross-sectional view of a digital single-lens reflex camera equipped with an optical system according to the present embodiment. It is a flowchart for demonstrating the manufacturing method of the optical system which concerns on this embodiment. It is explanatory drawing which shows an example of the layer structure of an antireflection film. It is a graph which shows the spectral characteristic of an antireflection film. It is a graph which shows the spectral characteristics of the antireflection film concerning a modification. It is a graph which shows the incident angle dependence of the spectral characteristic of the antireflection film concerning a modification. It is a graph which shows the spectral characteristics of the anti-reflective film produced with the prior art. It is a graph which shows the incident angle dependence of the spectral characteristic of the anti-reflective film produced with the prior art.

  Hereinafter, preferred embodiments of the present application will be described. The optical system according to the present embodiment includes, in order from the object side, a first lens group, a second lens group having a negative refractive power, and a third lens group having a positive refractive power. The lens group is fixed in the optical axis direction with respect to the image plane. The second lens group is an anti-vibration lens group that is displaced so as to have a component in a direction orthogonal to the optical axis to displace the image.

  In the optical system according to this embodiment, the distance on the optical axis from the lens surface closest to the image plane of the second lens unit to the paraxial image plane of the entire system at the time of focusing on infinity is Σdvr, When the focal length of the entire system at the time of focusing is f, the following conditional expression (1) is satisfied.

2.00 <Σdvr / f <5.00 (1)

  In order to secure a back focus enough to use a short focal length lens in a single-lens reflex camera or digital camera, the height of the marginal ray from the optical axis is set higher at the time of emission than at the time of incidence on the lens. It is known that it is effective to have a so-called wide converter characteristic capable of making the pupil magnification larger than one. In addition, even when there is no back focus restriction, it is effective to use the configuration having the wide converter characteristics as described above in order to compensate for the shortage of peripheral light amount that becomes conspicuous as the angle of view increases.

  A so-called retrofocus lens type with a large aperture of about F1.4 has been proposed. Here, when an anti-vibration mechanism is introduced to such an optical system having a wide angle of view, it becomes a problem where the anti-vibration lens is inserted. The “marginal ray” is a ray farthest from the optical axis among rays reaching the image height 0.

  In a retrofocus lens, the lens group on the object side has a strong negative refractive power, and the lens group on the image plane side has an asymmetric refractive power arrangement with a strong positive refractive power. This makes it difficult to correct negative distortion and coma. Therefore, it is necessary to correct aberrations as much as possible with the lens group alone. If such aberration correction is not sufficient for each lens group alone, spherical aberration, coma aberration, and decentering coma will occur when the subsequent lens group is shaken or when focusing on an object at a short distance. Aberration and curvature of field occur greatly.

  Therefore, in the optical system according to the present embodiment, a first lens group having a positive or negative refractive power, a second lens group having a negative refractive power, and a third lens having a positive refractive power in order from the object side. The arrangement of groups was adopted. Accordingly, the first lens group is considered as the above-described wide converter unit, and optimal aberration correction is performed. Further, since the anti-vibration lens group (hereinafter also referred to as “second lens group”) has a negative refractive power, even when combined with the third lens group, the refractive power arrangement of the retrofocus lens is taken so that the back focus and the imaging device It becomes easy to optimize the angle of incidence of the light beam on. As a result of such a configuration, it is possible to satisfactorily correct spherical aberration and coma. Further, coma aberration, particularly sagittal coma aberration, can be effectively corrected for the peripheral luminous flux because the second lens group has negative refractive power. As a result, good aberration correction can be realized without increasing the lens diameter. In addition, since the lens surface closest to the object has a shape with the concave surface facing the object, the above-described effects can be further exhibited.

  Further, the optical system according to the present embodiment satisfies the above-described conditional expression (1) that defines an effective range in which good imaging performance can be exhibited even during image stabilization while maintaining a balance with aberration correction. The configuration. Conditional expression (1) defines how far the second lens group, which is an anti-vibration lens group, is away from the image plane by a ratio to the focal length of the entire system. This conditional expression (1) means that the optical performance is particularly good when the image stabilizing lens group (second lens group) is located too close to the image plane or far from the focal plane. It is because it cannot be demonstrated at the time of shaking.

  Conventionally, as a big problem when introducing an anti-vibration mechanism in a wide-angle lens such as the optical system according to the present embodiment, it is difficult to correct astigmatism fluctuations when the second lens group, which is an anti-vibration lens group, is decentered. Met. In addition, with a large aperture lens, it is difficult to correct decentration coma when the anti-vibration lens group (second lens group) is decentered. The reason for this is that the angle at which the light beam of the peripheral image height is incident on each refracting surface of the second lens group, which is an anti-vibration lens group, varies greatly when decentered, resulting in a balance of astigmatism, coma, and the like. It is derived from the fact that it is greatly collapsed and cannot be corrected. Therefore, a relatively large number of lens groups having the same refractive power as that of the anti-vibration lens group (second lens group) are gathered, and the anti-vibration lens is located in the vicinity of one of these lens groups. When the second lens group, which is a group, is arranged, it is less necessary to perform high-order aberrations in the anti-vibration lens group (second lens group) and the lens groups before and after the anti-vibration lens group (second lens group). This is advantageous for aberration correction when the lens group) is decentered. As described above, the optical system according to the present embodiment is in the vicinity of the first lens group in which a relatively large number of lens groups having the same negative refractive power as that of the second lens group that is the anti-vibration lens group are gathered. The second lens group which is the anti-vibration lens group is arranged. As a result, the second lens group which is the anti-vibration lens group has the conditional expression (1) described above with respect to the image plane. Good aberration correction was achieved by being far enough to satisfy.

  In addition, when the anti-vibration lens group (second lens group) is arranged at a position close to the image plane in the retrofocus lens, it is difficult to arrange a mechanism for performing focusing. This is because, considering the load of the focusing unit capable of the autofocus mechanism, it is advantageous to perform the focusing unit relatively at a position closer to the image plane side of the lens. For this reason, if the second lens group, which is an anti-vibration lens group, is arranged at a position close to the image plane, it is forced to be arranged close to the focusing portion. As a result, it is necessary to reduce the moving stroke when focusing on a short-distance object using the focusing lens group. For this purpose, the refractive power of the third lens group must be increased. As a result, correction of spherical aberration and coma becomes difficult, which is not preferable. Similarly, if the anti-vibration lens group (second lens group) tries to obtain a sufficient anti-vibration effect with a small amount of decentering, the anti-vibration lens group (second lens group) also needs a strong refractive power. Both coma and astigmatism fluctuations at the time of decentration are difficult to correct, which is not preferable.

  If the upper limit value of conditional expression (1) is exceeded, the second lens group, which is an anti-vibration lens group, is too close to the object side with respect to the entire lens, so the total length of the lens tends to be long. As a result, it is necessary to make the refractive power of the first lens unit stronger than the optimum value for correcting aberrations in order to prevent the peripheral light amount from being insufficient, which is undesirable because distortion, field curvature, and the like deteriorate. . In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (1) to 4.50. 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 4.00.

  If the lower limit value of conditional expression (1) is not reached, the second lens group, which is an anti-vibration lens group, is too much on the image plane side with respect to the entire lens. Group) and the third lens group require a strong refractive power. As a result, it is difficult to correct both coma and astigmatism fluctuations when the anti-vibration lens group (second lens group) is decentered. Absent. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (1) to 2.20. 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 2.40.

  In the optical system according to the present embodiment, an antireflection film is provided on at least one of the optical surfaces of the first lens group and the second lens group, and the antireflection film is a layer formed by using a wet process. At least one layer. With this configuration, the optical system according to the present embodiment can reduce ghosts and flares caused by reflection of light from an object on an optical surface, thereby achieving high imaging performance.

  In the optical system according to the present embodiment, the antireflection film is preferably a multilayer film, and the layer formed using the wet process is preferably the outermost layer among the layers constituting the multilayer film. . In this way, since the difference in refractive index with air can be reduced, it is possible to reduce the reflection of light and further reduce ghosts and flares.

  In the optical system according to the present embodiment, it is preferable that the refractive index nd is 1.30 or less, where nd is the refractive index of the layer formed using the wet process. In this way, since the difference in refractive index with air can be reduced, it is possible to reduce the reflection of light and further reduce ghosts and flares.

  In the optical system according to the present embodiment, it is preferable that the optical surface provided with the antireflection film is a concave lens surface when viewed from the aperture stop. In the first lens group and the second lens group, reflected light is likely to be generated on a concave lens surface when viewed from the aperture stop. Therefore, by forming an antireflection film on such a lens surface, ghost and flare can be effectively prevented. Can be reduced.

  In the optical system according to the present embodiment, the concave lens surface viewed from the aperture stop provided with the antireflection film is preferably a lens surface on the image plane side. In the first lens group and the second lens group, reflected light is likely to be generated on the lens surface on the concave image surface side when viewed from the aperture stop. Therefore, by forming an antireflection film on such a lens surface, ghost and flare are formed. Can be effectively reduced.

  In the optical system according to the present embodiment, the concave lens surface viewed from the aperture stop provided with the antireflection film is preferably an object-side lens surface. In the first lens group and the second lens group, reflected light is likely to be generated on the concave object-side lens surface when viewed from the aperture stop. Therefore, by forming an antireflection film on such a lens surface, ghosts and flares are prevented. It can be effectively reduced.

  In the optical system according to the present embodiment, it is preferable that the optical surface provided with the antireflection film is a concave lens surface when viewed from the object side. In the first lens group and the second lens group, reflected light is likely to be generated on a concave lens surface when viewed from the object side. Therefore, by forming an antireflection film on such a lens surface, ghosts and flares can be effectively prevented. Can be reduced.

  In the optical system according to the present embodiment, the concave lens surface viewed from the object side provided with the antireflection film is preferably a lens surface on the image plane side. In the first lens group and the second lens group, reflected light is likely to be generated on the lens surface on the concave image surface side when viewed from the object side. Therefore, by forming an antireflection film on such a lens surface, ghost and flare are formed. Can be effectively reduced.

  In the optical system according to the present embodiment, it is preferable that the concave lens surface viewed from the object side provided with the antireflection film is an object side lens surface. In the first lens group and the second lens group, reflected light is likely to be generated on a concave object side lens surface when viewed from the object side. Therefore, by forming an antireflection film on such a lens surface, ghost and flare are prevented. It can be effectively reduced.

  In the optical system according to the present embodiment, the antireflection film is not limited to a wet process, and may be formed by a dry process or the like. At this time, it is preferable that the antireflection film includes at least one layer having a refractive index of 1.30 or less. By making the antireflection film include at least one layer having a refractive index of 1.30 or less, even if the antireflection film is formed by a dry process or the like, the same effect as that obtained by using a wet process can be obtained. Can be obtained. At this time, the layer having a refractive index of 1.30 or less is preferably the most surface layer among the layers constituting the multilayer film.

  In the optical system according to the present embodiment, when the lateral magnification of the second lens group at the time of focusing on infinity is βvr and the lateral magnification of the third lens group at the time of focusing on infinity is β3, the following conditions are satisfied. It is desirable to satisfy Formula (2).

0.15 <| (1-βvr) × β3 | <0.50 (2)

  Conditional expression (2) indicates a component in a direction in which the image is substantially orthogonal to the optical axis on the image plane with respect to a movement amount having a component in a direction orthogonal to the optical axis of the second lens group which is the anti-vibration lens group. This is a condition that prescribes the percentage of movement that can be held.

  If the upper limit of conditional expression (2) is exceeded, the refractive power of the second lens group, which is the anti-vibration lens group, becomes too strong. As a result, aberration correction can be performed for both coma and astigmatism variations during decentering. It becomes difficult and not preferable.

  If the upper limit value of conditional expression (2) is exceeded, the lateral magnification of the third lens group becomes too large in addition to the fact that the refractive power of the image stabilizing lens group (second lens group) becomes too strong as described above. This means that the refractive power of the third lens group is too strong than the appropriate value, and as a result, spherical aberration, coma aberration and the like are also deteriorated. In addition, since the lateral magnification of the third lens group is too higher than an appropriate value, fluctuations in coma and astigmatism at the time of decentering due to decentering of the anti-vibration lens group (second lens group) are excessively enlarged. As a result, it becomes difficult to correct fluctuations in coma and astigmatism when the image stabilizing lens group (second lens group) is decentered.

  In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (2) to 0.45. In order to further secure the effect of the present embodiment, it is more preferable to set the upper limit of conditional expression (2) to 0.42.

  If the lower limit of conditional expression (2) is not reached, the amount of movement of the anti-vibration lens group (second lens group) necessary for anti-vibration control becomes larger than the appropriate value, and as a result, the anti-vibration lens Both the coma and astigmatism fluctuations when the lens group (second lens group) is decentered are difficult to correct, which is not preferable. In addition, the driving means such as an actuator for driving the anti-vibration lens group (second lens group) also becomes large. As a result, since the distance between the lens groups is compressed from an appropriate value, the refractive power of each lens group becomes too strong, and spherical aberration, coma aberration and the like are also deteriorated.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (2) to 0.18. In order to further secure the effect of the present embodiment, it is more preferable to set the lower limit of conditional expression (2) to 0.21.

  The optical system according to this embodiment satisfies the following conditional expression (3), where f is the focal length of the entire system at the time of focusing on infinity and f2 is the focal length of the second lens group. Is desirable.

−0.35 <f / f2 <−0.07 (3)

  Conditional expression (3) is a conditional expression for defining the focal length f2 of the second lens group which is the image stabilizing lens group.

  If the upper limit of conditional expression (3) is exceeded, the refractive power of the anti-vibration lens group (second lens group) becomes too weak, so this anti-vibration lens group (second lens group) necessary for anti-vibration control ) Becomes larger than an appropriate value, and as a result, coma aberration and astigmatism variation at the time of decentering of the anti-vibration lens group (second lens group) are difficult to correct aberrations, which is not preferable. In addition, driving means such as an actuator for driving the anti-vibration lens group (second lens group) also becomes large. As a result, since the distance between the lens groups is compressed from an appropriate value, the refractive power of each lens group becomes too strong, so that spherical aberration, coma aberration and the like are also deteriorated.

  In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (3) to −0.10. In order to further secure the effect of the present embodiment, it is more preferable to set the upper limit of conditional expression (3) to −0.12.

  If the lower limit of conditional expression (3) is not reached, the refractive power of the image stabilizing lens group (second lens group) becomes too strong. As a result, the eccentricity of the image stabilizing lens group (second lens group) is increased. Both coma and astigmatism fluctuations at the time are not preferable because it becomes difficult to correct aberrations.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (3) to −0.31. In order to further secure the effect of the present embodiment, it is more preferable to set the lower limit of conditional expression (3) to −0.28.

  In general, it is known that an optical surface that is concentric with respect to an aperture stop hardly generates astigmatism. As a big problem when an anti-vibration mechanism is introduced in an optical system with a wide angle of view, astigmatism at the time of decentering and fluctuations in this astigmatism can be mentioned. The reason for this is that the angle at which the peripheral image height is incident on each refractive surface of the anti-vibration lens group varies greatly during decentering, and as a result, the balance of astigmatism, coma, etc. is greatly lost and corrected. It comes from the fact that it cannot be done. Therefore, in the optical system according to the present embodiment, the optical surface is concentric with respect to the aperture stop S, and the peripheral image height is high with respect to each refractive surface of the image stabilizing lens group (second lens group) even when decentered. The angle at which the light beam is incident is not changed greatly at the time of eccentricity. As a result, astigmatism and coma variation at the time of decentration were corrected satisfactorily.

  Thus, in the optical system according to the present embodiment, it is desirable that the aperture stop S is disposed on the image plane side with respect to the second lens group, and the aperture stop S is disposed in the third lens group. It is more desirable. In this case, it is desirable to arrange lens components before and after the aperture stop S.

  In the optical system according to the present embodiment, the light beam emitted from the second lens group that is the anti-vibration lens group becomes divergent light. Here, when there is no lens group between the second lens group and the aperture stop S, the light beam that has passed through the aperture stop S has a higher incident height with respect to the lens group on the image plane side than the aperture stop S. become. As a result, since spherical aberration and coma aberration deteriorate, it is desirable to have a lens component between the second lens group and the aperture stop S. From the above viewpoint, it is more desirable that the lens component between the second lens group and the aperture stop S has a positive refractive power. In addition, since it is possible to correct aberration before and after the aperture stop S by having a lens component on the image plane side from the aperture stop S, the third lens group may have a lens component before and after the aperture stop S. preferable. With this configuration, spherical aberration and coma can be favorably corrected. From the above viewpoint, it is more desirable that the lens component on the image plane side from the aperture stop S has a positive refractive power. In addition, a lens frame may be used instead of a member as an aperture stop.

  In the optical system according to the present embodiment, it is desirable that the third lens group moves toward the object side when focusing from an object at infinity to an object at a short distance. As a focusing method for an optical system having a wide angle of view, a so-called rear focus type in which only the image plane side is moved from the aperture stop S is known. However, in an optical system with a large aperture and a wide angle of view, variations in spherical aberration, coma and field curvature are not desirable. Therefore, in the optical system according to the present embodiment, the third lens group has lens components before and after the aperture stop S, so that spherical aberration, coma aberration, and image can be obtained even when focusing from an infinite object to a close object. It became possible to suppress the aberration fluctuation of the surface curvature. In addition, since there are lens components before and after the aperture stop S as described above, the spherical aberration and the coma aberration can be favorably corrected as described above.

  Next, an optical apparatus equipped with the optical system according to this embodiment will be described. FIG. 26 shows a schematic configuration diagram of a single-lens reflex camera 1 (hereinafter simply referred to as a camera) equipped with an optical system according to the present embodiment having an image stabilization function shown in a first example described later. In this camera 1, light from a subject (not shown) is collected by a photographic lens (SL) 2 having an anti-vibration function to be described later, reflected by a quick return mirror 3, and imaged on a focusing screen 4. The subject image formed on the focusing screen 4 is reflected by the pentaprism 5 a plurality of times and can be viewed as an erect image by the photographer via the eyepiece 6.

  The photographer observes the subject image through the eyepiece 6 while half-pressing a release button (not shown), determines the focus on the subject and the shooting composition, and then fully presses the release button. When the release button is fully pressed, the quick return mirror 3 is flipped upward, the light from the subject is received by the image sensor 7 and a photographed image is acquired and recorded in a memory (not shown). When the release button is fully pressed, the tilt of the photographic lens 2 (camera 1) is detected by a sensor 8 (for example, an angle sensor) built in the photographic lens 2 (optical system SL) and transmitted to the CPU 9. Then, the amount of rotation blur is detected, and the lens driving means 10 is driven to drive the camera shake correction lens group so as to have a component in the direction orthogonal to the optical axis, and image blur on the image sensor 7 when camera shake occurs is corrected. . In this way, the optical apparatus 1 including the photographing lens 2 (optical system SL) having a vibration-proof function described later is configured. The camera 1 shown in FIG. 26 may hold the optical system SL in a detachable manner, or may be formed integrally with the optical system SL. Further, a mirrorless camera that does not have a quick return mirror or the like may be used, and the same effect as the above camera can be achieved. The camera 1 can be mounted not only with the first embodiment described above but also with a photographic lens of another embodiment.

  Hereinafter, an outline of the method of manufacturing the optical system of the present embodiment will be described with reference to FIG. In FIG. 27, each lens is arranged to prepare a lens group (step S100). In the optical system according to the present embodiment, an antireflection film is provided on at least one of the optical surfaces in the first lens group and the second lens group, and the antireflection film is a layer formed using a wet process. At least one layer.

  Specifically, in this embodiment, for example, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a convex surface facing the object side, and a negative meniscus lens having a convex surface facing the object side. The first lens group G1 includes a cemented lens with a shaped aspherical negative lens L13, a cemented lens with a biconvex positive lens L14 and a biconcave negative lens L15, and a biconvex positive lens L16. In order from the object side, a cemented lens of a biconcave negative lens L21 and a positive meniscus lens L22 having a convex surface facing the object side is disposed to form the second lens group G2, and convex from the object side to the object side. Positive meniscus lens L31 with a convex surface, biconvex positive lens L32, negative meniscus lens L33 with a convex surface facing the object side, aperture stop S, biconcave negative lens L34 and biconvex non- A cemented lens of a surface positive lens L35, a positive lens L36 of a biconvex shape, and a third lens group G3 disposed a positive meniscus lens L37 having a convex surface directed toward the image side.

  At this time, the first lens group G1 is disposed so as to be fixed in the optical axis direction with respect to the image plane (step S200). The second lens group G2 is arranged so as to move so as to have a component in a direction orthogonal to the optical axis (step S300).

  The distance between these lens groups on the optical axis from the lens surface closest to the image plane of the second lens group G2 at the time of focusing at infinity to the paraxial image plane of the entire system is Σdvr, and focusing at infinity is performed. When the focal length of the entire system at the time is f, the arrangement is performed so as to satisfy the above-described conditional expression (1) (step S400).

  Hereinafter, each example of the optical system according to the present embodiment will be described with reference to the drawings. 1, 5, 8, 11, 14, 17, 20, and 23 are cross-sectional views illustrating the lens configuration of the optical system SL (SL <b> 1 to SL <b> 8) according to each example.

  As shown in FIGS. 1 and 5, the optical systems SL1 and SL2 according to the first and second examples have a first lens group G1 having a negative refractive power and a negative refractive power in order from the object side. It is composed of a second lens group G2 and a third lens group G3 having a positive refractive power.

  On the other hand, as shown in FIGS. 8, 11, 14, 17, 20, and 23, the optical systems SL3 to SL8 according to the third to eighth examples have positive refractive power in order from the object side. The first lens group G1 includes a second lens group G2 having a negative refractive power, and a third lens group G3 having a positive refractive power.

  In each embodiment, the first lens group G1 is fixed in the optical axis direction with respect to the image plane, and the second lens group G2 moves so as to have a component substantially perpendicular to the optical axis and moves on the image plane. This is an anti-vibration lens group for displacing the image. The aperture stop S is disposed in the third lens group G3, has lens components having a positive refractive power before and after the aperture stop S (except for the eighth embodiment), and focuses on a short-distance object. The third lens group G3 moves to the object side.

  In each embodiment, the height of the aspheric surface in the direction perpendicular to the optical axis is y, and the distance (sag amount) along the optical axis from the tangential plane of the apex of each aspheric surface to each aspheric surface at height y. Is S (y), r is the radius of curvature of the reference sphere (paraxial radius of curvature), κ is the conic constant, and An is the nth-order aspheric coefficient, and is expressed by the following equation (a). . In the following examples, “E-n” represents “× 10-n”.

S (y) = (y2 / r) / {1+ (1-κ × y2 / r2) 1/2}
+ A4 x y4 + A6 x y6 + A8 x y8 (a)

  In each embodiment, the secondary aspheric coefficient A2 is zero. In the table of each example, an aspherical surface is marked with * on the left side of the surface number.

[First embodiment]
FIG. 1 is a diagram showing a lens configuration of an optical system SL1 according to the first example of the present application. In the optical system SL1 of FIG. 1, the first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a convex surface facing the object side, and a convex surface facing the object side. A negative meniscus lens-shaped aspherical negative lens L13, a biconvex positive lens L14 and a biconcave negative lens L15, and a biconvex positive lens L16. Yes.

  The second lens group G2 includes, in order from the object side, a cemented lens of a biconcave negative lens L21 and a positive meniscus lens L22 having a convex surface facing the object side.

  The third lens group G3 includes, in order from the object side, a positive meniscus lens L31 having a convex surface directed toward the object side, a positive lens L32 having a biconvex shape, a negative meniscus lens L33 having a convex surface directed toward the object side, an aperture stop S, and a biconcave lens. The lens includes a cemented lens of a negative lens L34 having a shape and an aspherical positive lens L35 having a biconvex shape, a positive lens L36 having a biconvex shape, and a positive meniscus lens L37 having a convex surface facing the image plane I side.

  In the first embodiment, the lens surface (surface number 2) on the image plane I side of the negative meniscus lens L11 of the first lens group G1, and the object side lens of the biconcave negative lens L21 of the second lens group G2. An antireflection film described later is formed on the surface (surface number 11).

  It should be noted that the focal length of the entire system is f, and the image blur correction coefficient (ratio of the amount of image movement on the imaging surface to the amount of movement of the moving lens group in shake correction) corrects rotational shake at an angle θ with a K lens. For this, the moving lens group for blur correction may be moved in the direction orthogonal to the optical axis by (f · tan θ) / K. In the first example, since the image stabilization coefficient is 0.306 and the focal length is 28.50 (mm), the amount of movement of the second lens group G2 for correcting the rotation blur of 0.70 °. Is 1.14 (mm).

  Table 1 below lists values of specifications of the first embodiment. In Table 1, f represents the focal length, FNO represents the F number, 2ω represents the angle of view (unit: °), and Bf represents the back focus. Also, 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 interval 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 curvature radius “∞” of the object plane and the image plane, and the curvature radius 0.000 of the aperture stop each indicate a plane. Further, 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) First Example
f = 28.50
FNO = 1.45
2ω = 75.6
Image height = 21.6
Total length = 133.3

Surface number Curvature radius Surface spacing Refractive index Abbe number object surface ∞ ∞
1 84.252 2.40 1.74100 52.67
2 30.284 6.24
3 57.477 2.10 1.77250 49.60
4 36.791 0.20 1.55389 38.09
* 5 32.506 12.47
6 498.367 6.33 1.74400 44.79
7 -54.700 1.30 1.52699 53.00
8 320.562 0.20
9 84.738 5.36 1.74806 50.00
10 -139.358 5.00
11 -75.418 1.30 1.48749 70.40
12 53.719 2.98 1.83400 37.16
13 118.654 (d13)
14 45.171 3.76 1.69680 55.52
15 121.944 0.20
16 39.937 6.09 1.69680 55.52
17 -136.788 0.20
18 138.447 1.30 1.62004 36.30
19 27.404 5.00
20 0.000 6.67 Aperture stop S
21 -22.640 1.30 1.78472 25.68
22 65.850 5.67 1.77250 49.60
* 23 -59.294 1.14
24 256.664 6.00 1.74100 52.67
25 -37.599 0.20
26 -56.322 4.25 1.77250 49.61
27 -31.870 (Bf)
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length First lens group 1 733.43
Second lens group 11 -141.94
Third lens group 14 42.52

  In the first embodiment, the lens surfaces of the fifth surface and the 23rd surface are aspherical. The following Table 2 shows aspheric data, that is, the values of the conic constant κ and the aspheric constants A4 to A8.

(Table 2)
κ A4 A6 A8
5th surface 0.042900 -6.54648E-08 -1.07103E-09 -2.03329E-12
Side 23 -19.496500 2.12065E-06 3.80233E-08 -5.28645E-11

  In the first example, the axial air gap d13 between the second lens group G2 and the third lens group G3 and the back focus Bf change during focusing. Table 3 below shows variable intervals at each focal length in the infinitely focused state and the photographing magnification of -0.0333 times. Note that d0 is the distance from the object to the lens surface closest to the object, β is the shooting magnification, and the other embodiments are the same, and the description thereof is omitted.

(Table 3)
Infinite focus state Intermediate shooting distance state
d0 or β ∞ -0.0333
d13 7.55 6.52
Bf 38.11 39.14

  Table 4 below shows values corresponding to the conditional expressions in the first embodiment. In Table 4, Σdvr is the distance on the optical axis from the lens surface closest to the image plane of the second lens group G2 at the time of focusing at infinity to the paraxial image plane of the entire system, and βvr is focused at infinity. Βvr is the lateral magnification of the second lens group G2 at the time, β3 is the lateral magnification of the third lens group at the time of focusing on infinity, f is the focal length of the entire system, and f2 is the focal length of the second lens group G2. Each distance is represented. The description of the above symbols is the same in the following embodiments.

(Table 4)
(1) Σdvr / f = 3.07
(2) | (1-βvr) × β3 | = 0.31
(3) f / f2 = -0.20

  FIG. 2A shows an aberration diagram in the infinite focus state in the first embodiment, and FIG. 3A shows an aberration diagram in an intermediate shooting distance state. Further, FIG. 2B shows a coma aberration diagram when the blur correction is performed with respect to the rotational blur of 0.70 ° in the infinite focus state in the first embodiment, and 0.70 ° in the intermediate shooting distance state. FIG. 3B shows a coma aberration diagram when the shake correction for the rotational shake is performed. In each aberration diagram, FNO is the F number, NA is the numerical aperture, Y is the image height, A is the incident angle of the principal ray, D is the d-line (λ = 587.6 nm), and G is the g-line ( (λ = 435.8 nm), respectively. In the aberration diagrams showing astigmatism, the solid line shows the sagittal image plane, and the broken line shows the meridional image plane. In the coma aberration, the broken line shows a sagittal lateral aberration diagram. The description of these aberration diagrams is the same in the following examples.

  As is apparent from the respective aberration diagrams, it is clear that the optical system SL1 according to the first example has various aberrations corrected well and has excellent imaging performance.

  FIG. 4 shows a state where a ghost is generated by the light beam BM incident from the object side in the optical system SL1 according to the first example. In FIG. 4, when a light beam BM from the object side enters the optical system SL1 as shown in the drawing, the object-side lens surface (the first reflected light generating surface, whose surface number is the birefringent negative lens L21) 11), and the reflected light is reflected again on the image side lens surface (second reflected light generating surface, whose surface number is 2) in the negative meniscus lens L11 of the first lens group G1, and the image is reflected again. Surface I is reached and ghosts and flares are generated. The first reflected light generation surface (surface number 11) is a concave lens surface when viewed from the object, and the second reflected light generation surface (surface number 2) is a concave shape when viewed from the aperture stop. It is a lens surface. By forming an antireflection film corresponding to a wide incident angle in a wider wavelength range on such a surface, ghosts and flares can be effectively reduced.

[Second Embodiment]
FIG. 5 is a diagram showing a lens configuration of the optical system SL2 according to the second example of the present application. In the optical system SL2 of FIG. 5, the first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a convex surface facing the object side, and a convex surface facing the object side. A cemented lens with an aspheric negative lens L13 having a negative meniscus lens shape, a cemented lens with a positive meniscus lens L14 having a convex surface facing the image surface I and a negative meniscus lens L15 having a convex surface facing the image surface I, and This is composed of a biconvex positive lens L16.

  The second lens group G2 includes, in order from the object side, a cemented lens of a biconcave negative lens L21 and a positive meniscus lens L22 having a convex surface facing the object side.

  The third lens group G3 includes, in order from the object side, a positive meniscus lens L31 having a convex surface directed toward the object side, a positive lens L32 having a biconvex shape, a negative meniscus lens L33 having a convex surface directed toward the object side, an aperture stop S, and a biconcave lens. The lens includes a cemented lens of a negative lens L34 having a shape and an aspherical positive lens L35 having a biconvex shape, a positive lens L36 having a biconvex shape, and a positive meniscus lens L37 having a convex surface facing the image plane I side.

  In the second embodiment, the image surface I side lens surface (surface number 2) of the negative meniscus lens L11 of the first lens group G1 and the image surface I side of the biconvex positive lens L16 of the first lens group G1. An antireflection film described later is formed on the lens surface (surface number 10).

  It should be noted that the focal length of the entire system is f, and the image blur correction coefficient (ratio of the amount of image movement on the imaging surface to the amount of movement of the moving lens group in shake correction) corrects rotational shake at an angle θ with a K lens. For this, the moving lens group for blur correction may be moved in the direction orthogonal to the optical axis by (f · tan θ) / K. In the second embodiment, since the image stabilization coefficient is 0.306 and the focal length is 27.99 (mm), the amount of movement of the second lens group G2 for correcting the rotation blur of 0.70 °. Is 1.12 (mm).

  Table 5 below shows values of specifications of the second embodiment.

(Table 5) Second Example
f = 27.99
FNO = 1.45
2ω = 76.7
Image height = 21.6
Total length = 133.3

Surface number Curvature radius Surface spacing Refractive index Abbe number object surface ∞ ∞
1 67.583 2.40 1.74100 52.67
2 30.054 6.93
3 68.341 2.10 1.77250 49.60
4 36.441 0.20 1.55389 38.09
* 5 33.585 12.50
6 -176.482 3.98 1.74400 44.79
7 -61.111 1.30 1.52599 53.31
8 -288.957 0.20
9 150.265 5.50 1.74806 50.00
10 -78.414 5.00
11 -63.966 1.30 1.48749 70.40
12 68.577 2.82 1.83400 37.16
13 186.927 (d13)
14 39.297 4.23 1.69680 55.52
15 103.599 0.20
16 39.021 6.42 1.69680 55.52
17 -148.831 0.20
18 113.771 1.30 1.61266 44.46
19 26.212 5.00
20 0.000 7.01 Aperture stop S
21 -22.122 1.30 1.78472 25.68
22 49.850 5.35 1.77250 49.60
* 23 -53.784 1.79
24 407.632 6.00 1.75500 52.31
25 -36.823 0.20
26 -51.964 4.18 1.77250 49.61
27 -31.344 (Bf)
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length 1st lens group 1 -858.75
Second lens group 11 -141.98
Third lens group 14 43.51

  In the second embodiment, the lens surfaces of the fifth surface and the 23rd surface are formed in an aspherical shape. Table 6 below shows the data of the aspheric surface, that is, the values of the vertex curvature radius R, the conic constant κ, and the aspheric constants A4 to A8.

(Table 6)
κ A4 A6 A8
5th surface 0.016000 8.67227E-07 -2.62240E-10 -1.58840E-12
Surface 23 -19.875800 -9.08714E-07 5.51987E-08 -7.97050E-11

  In the second embodiment, the axial air distance d13 between the second lens group G2 and the third lens group G3 and the back focus Bf change during focusing. Table 7 below shows the variable intervals at the respective focal lengths in the infinitely focused state and the photographing magnification of -0.0333 times.

(Table 7)
Infinite focus state Intermediate shooting distance state
d0 or β ∞ -0.0333
d13 7.81 6.74
Bf 38.12 39.18

  Table 8 below shows values corresponding to the conditional expressions in the second embodiment.

(Table 8)
(1) Σdvr / f = 3.18
(2) | (1-βvr) × β3 | = 0.31
(3) f / f2 = -0.20

  FIG. 6A shows an aberration diagram in the infinite focus state in the second embodiment, and FIG. 7A shows an aberration diagram in the intermediate shooting distance state. Further, FIG. 6B shows a coma aberration diagram when the blur correction is performed with respect to the rotational blur of 0.70 ° in the infinite focus state in the second embodiment, and 0.70 ° in the intermediate shooting distance state. FIG. 7B shows a coma aberration diagram when the shake correction for the rotational shake is performed.

  As is apparent from the respective aberration diagrams, it is clear that in the second embodiment, various aberrations are corrected well and the imaging performance is excellent.

[Third embodiment]
FIG. 8 is a diagram showing a lens configuration of the optical system SL3 according to the third example of the present application. In the optical system SL3 of FIG. 8, the first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a convex surface facing the object side, and a convex surface facing the object side. A negative meniscus lens-shaped aspherical negative lens L13, a positive meniscus lens L14 having a convex surface facing the image plane I, and a biconvex positive lens L15.

  The second lens group G2 includes, in order from the object side, a cemented lens of a biconcave negative lens L21 and a positive meniscus lens L22 having a convex surface facing the object side.

  The third lens group G3 includes, in order from the object side, a positive meniscus lens L31 having a convex surface directed toward the object side, a positive lens L32 having a biconvex shape, a negative meniscus lens L33 having a convex surface directed toward the object side, an aperture stop S, and a biconcave lens. The lens includes a cemented lens of a negative lens L34 having a shape and an aspherical positive lens L35 having a biconvex shape, a positive lens L36 having a biconvex shape, and a positive meniscus lens L37 having a convex surface facing the image plane I side.

  In the third example, the lens surface (surface number 2) on the image plane I side in the negative meniscus lens L11 of the first lens group G1, and the object side lens in the biconcave negative lens L21 of the second lens group G2. An antireflection film described later is formed on the surface (surface number 10).

  It should be noted that the focal length of the entire system is f, and the image blur correction coefficient (ratio of the amount of image movement on the imaging surface to the amount of movement of the moving lens group in shake correction) corrects rotational shake at an angle θ with a K lens. For this, the moving lens group for blur correction may be moved in the direction orthogonal to the optical axis by (f · tan θ) / K. In the third example, since the image stabilization coefficient is 0.306 and the focal length is 28.44 (mm), the amount of movement of the second lens group G2 for correcting the rotation blur of 0.70 °. Is 1.13 (mm).

  Table 9 below shows values of specifications of the third embodiment.

(Table 9) Third Example
f = 28.44
FNO = 1.45
2ω = 75.8
Image height = 21.6
Total length = 133.3

Surface number Curvature radius Surface spacing Refractive index Abbe number object surface ∞ ∞
1 100.000 2.40 1.74100 52.67
2 30.472 6.11
3 61.820 2.10 1.77250 49.60
4 40.528 0.20 1.55389 38.09
* 5 34.996 11.06
6 -230.000 8.00 1.74397 44.85
7 -85.027 0.20
8 84.290 4.89 1.74397 44.85
9 -199.472 5.00
10 -74.412 1.30 1.48749 70.41
11 55.716 2.99 1.80100 34.96
12 131.420 (d12)
13 44.605 3.61 1.69680 55.52
14 108.329 0.20
15 38.431 6.09 1.69680 55.52
16 -159.242 0.20
17 116.847 1.30 1.62004 36.30
18 26.190 5.00
19 0.000 6.56 Aperture stop S
20 -23.170 2.29 1.76182 26.56
21 48.664 6.00 1.77250 49.60
* 22 -61.350 1.40
23 298.511 6.00 1.72916 54.66
24 -39.601 0.20
25 -63.162 4.44 1.77250 49.61
26 -33.521 (Bf)

[Lens focal length]
Lens group Start surface Focal length 1st lens group 1 553.08
Second lens group 10 -142.23
Third lens group 13 43.02

  In the third embodiment, the lens surfaces of the fifth surface and the twenty-second surface are formed in an aspheric shape. Table 10 below shows the aspheric data, that is, the values of the vertex curvature radius R, the conic constant κ, and the aspheric constants A4 to A8.

(Table 10)
κ A4 A6 A8
5th surface -0.116100 -8.06560E-07 -1.69170E-09 -1.57780E-12
Side 22 -17.884100 2.86500E-06 2.91840E-08 -3.77560E-11

  In the third example, the axial air distance d12 and the back focus Bf between the second lens group G2 and the third lens group G3 change during focusing. Table 11 below shows variable intervals at each focal length in an infinitely focused state and a photographing magnification of -0.0333 times.

(Table 11)
Infinite focus state Intermediate shooting distance state
d0 or β ∞ -0.0333
d12 7.47 6.45
Bf 38.32 39.34

  Table 12 below shows values corresponding to the conditional expressions in the third embodiment.

(Table 12)
(1) Σdvr / f = 3.13
(2) | (1-βvr) × β3 | = 0.31
(3) f / f2 = -0.20

  FIG. 9A shows an aberration diagram in the infinite focus state in the third embodiment, and FIG. 10A shows an aberration diagram in the intermediate shooting distance state. Further, FIG. 9B shows a coma aberration diagram when the blur correction is performed with respect to the rotational blur of 0.70 ° in the infinite focus state in the third embodiment, and 0.70 ° in the intermediate shooting distance state. FIG. 10B shows a coma aberration diagram when the shake correction for the rotational shake is performed.

  As is apparent from each aberration diagram, in the third example, it is clear that various aberrations are corrected favorably and the imaging performance is excellent.

[Fourth embodiment]
FIG. 11 is a diagram showing a lens configuration of the optical system SL4 according to the fourth example of the present application. In the optical system SL4 of FIG. 11, the first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a convex surface facing the object side, and a convex surface facing the object side. A cemented lens with an aspheric negative lens L13 having a negative meniscus lens shape facing, a cemented lens with a negative meniscus lens L14 having a convex surface facing the object side and a biconvex positive lens L15, and a positive lens L16 with a biconvex shape It is composed of

  The second lens group G2 includes, in order from the object side, a cemented lens of a biconcave negative lens L21 and a positive meniscus lens L22 having a convex surface facing the object side.

  The third lens group G3 includes, in order from the object side, a positive meniscus lens L31 having a convex surface directed toward the object side, a positive lens L32 having a biconvex shape, a negative meniscus lens L33 having a convex surface directed toward the object side, an aperture stop S, and a biconcave lens. The lens includes a cemented lens of a negative lens L34 having a shape and an aspherical positive lens L35 having a biconvex shape, a positive lens L36 having a biconvex shape, and a positive meniscus lens L37 having a convex surface facing the image plane I side.

  In the fourth example, the image surface I side lens surface (surface number 2) of the negative meniscus lens L11 of the first lens group G1 and the image surface I side of the biconvex positive lens L16 of the first lens group G1. An antireflection film described later is formed on the lens surface (surface number 10).

  It should be noted that the focal length of the entire system is f, and the image blur correction coefficient (ratio of the amount of image movement on the imaging surface to the amount of movement of the moving lens group in shake correction) corrects rotational shake at an angle θ with a K lens. For this, the moving lens group for blur correction may be moved in the direction orthogonal to the optical axis by (f · tan θ) / K. In the fourth embodiment, since the image stabilization coefficient is 0.290 and the focal length is 24.70 (mm), the amount of movement of the second lens group G2 for correcting the rotation blur of 0.70 °. Is 1.04 (mm).

  Table 13 below lists values of specifications of the fourth embodiment.

(Table 13) Fourth Example
f = 24.70
FNO = 1.44
2ω = 83.7
Image height = 21.6
Total length = 133.3

Surface number Curvature radius Surface spacing Refractive index Abbe number object surface ∞ ∞
1 70.260 2.40 1.74100 52.67
2 28.526 11.93
3 8844.268 2.10 1.77250 49.60
4 50.722 0.20 1.55389 38.09
* 5 41.921 12.50
6 298.509 2.27 1.75520 27.58
7 88.204 7.50 1.74397 44.85
8 -82.134 0.20
9 62.241 5.50 1.77250 49.61
10 -737.077 5.00
11 -96.957 1.30 1.58313 59.38
12 44.004 3.72 1.83400 37.16
13 128.781 (d13)
14 47.455 3.03 1.69680 55.52
15 90.837 0.20
16 33.070 5.62 1.68692 55.00
17 -440.765 0.20
18 66.442 1.30 1.63980 34.56
19 23.078 5.00
20 0.000 8.45 Aperture stop S
21 -20.977 1.30 1.78472 25.68
22 51.753 4.09 1.77250 49.60
* 23 -48.262 1.07
24 362.304 5.96 1.74100 52.67
25 -34.691 0.20
26 -49.773 4.51 1.77250 49.61
27 -28.781 (Bf)
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length First lens group 1 111.53
Second lens group 11 -147.13
Third lens group 14 42.48

  In the fourth embodiment, the lens surfaces of the fifth surface and the 23rd surface are formed in an aspherical shape. Table 14 below shows the data of aspheric surfaces, that is, the values of the vertex curvature radius R, the conic constant κ, and the aspheric constants A4 to A8.

(Table 14)
κ A4 A6 A8
5th surface 0.041600 -3.01610E-06 -1.30950E-10 -1.50790E-12
Surface 23 -23.208700 -6.21040E-06 1.01630E-07 -1.81570E-10

  In the fourth example, the axial air distance d13 between the second lens group G2 and the third lens group G3 and the back focus Bf change during focusing. Table 15 below shows variable intervals at each focal length in the infinitely focused state and the photographing magnification of -0.0333 times.

(Table 15)
Infinite focus state Intermediate shooting distance state
d0 or β ∞ -0.0333
d13 6.30 5.47
Bf 31.47 32.29

  Table 16 below shows values corresponding to the conditional expressions in the fourth embodiment.

(Table 16)
(1) Σdvr / f = 3.19
(2) | (1-βvr) × β3 | = 0.29
(3) f / f2 = -0.17

  FIG. 12A shows an aberration diagram in the infinite focus state in the fourth embodiment, and FIG. 13A shows an aberration diagram in the intermediate shooting distance state. Further, FIG. 12B shows a coma aberration diagram when the blur correction is performed with respect to the rotational blur of 0.70 ° in the infinite focus state in the fourth embodiment, and 0.70 ° in the intermediate shooting distance state. FIG. 13B shows a coma aberration diagram when the shake correction for the rotational shake is performed.

  As is apparent from each aberration diagram, it is clear that in the fourth example, various aberrations are corrected satisfactorily and the imaging performance is excellent.

[Fifth embodiment]
FIG. 14 is a diagram showing a lens configuration of an optical system SL5 according to the fifth example of the present application. In the optical system SL5 of FIG. 14, the first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a convex surface facing the object side, and a convex surface facing the object side. It is composed of a cemented lens with an aspheric negative lens L13 having a negative meniscus lens shape and a positive lens L14 having a biconvex shape.

  The second lens group G2 includes, in order from the object side, a cemented lens of a biconcave negative lens L21 and a positive meniscus lens L22 having a convex surface facing the object side.

  The third lens group G3 includes, in order from the object side, a biconvex positive lens L31, a negative meniscus lens L32 having a convex surface directed toward the image plane I, an aperture stop S, a biconcave negative lens L33, and a biconvex shape. The lens includes a cemented lens with an aspherical positive lens L34, a positive meniscus lens L35 having a convex surface facing the image surface I, and a positive meniscus lens L36 having a convex surface facing the image surface I.

  In the fifth embodiment, the lens surface (surface number 2) on the image plane I side of the negative meniscus lens L11 of the first lens group G1, and the object side lens of the biconcave negative lens L21 of the second lens group G2. An antireflection film described later is formed on the surface (surface number 8).

  It should be noted that the focal length of the entire system is f, and the image blur correction coefficient (ratio of the amount of image movement on the imaging surface to the amount of movement of the moving lens group in shake correction) corrects rotational shake at an angle θ with a K lens. For this, the moving lens group for blur correction may be moved in the direction orthogonal to the optical axis by (f · tan θ) / K. In the fifth embodiment, since the image stabilization coefficient is 0.272 and the focal length is 28.08 (mm), the amount of movement of the second lens group G2 for correcting the rotation blur of 0.70 °. Is 1.26 (mm).

  Table 17 below provides values of specifications of the fifth embodiment.

(Table 17) Fifth Example
f = 28.08
FNO = 1.84
2ω = 76.4
Image height = 21.6
Total length = 124.5

Surface number Curvature radius Surface spacing Refractive index Abbe number object surface ∞ ∞
1 69.946 2.40 1.74100 52.67
2 25.426 5.00
3 45.000 2.10 1.77250 49.60
4 26.915 0.20 1.55389 38.09
* 5 23.566 13.79
6 57.582 4.75 1.90366 31.31
7 -391.763 4.00
8 -65.539 1.30 1.55857 45.21
9 56.097 3.60 1.74397 44.85
10 836.329 (d10)
11 49.880 6.47 1.74100 52.67
12 -37.637 1.30 2.00069 25.46
13 -61.930 11.01
14 0.000 5.00 Aperture stop S
15 -26.632 2.50 1.76182 26.56
16 69.109 5.84 1.77250 49.60
* 17 -110.000 1.44
18 -148.037 3.02 1.72916 54.66
19 -44.972 0.20
20 -87.642 3.82 1.77250 49.60
21 -31.772 (Bf)
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length 1st lens group 1 -169.53
Second lens group 8 -163.95
Third lens group 11 42.15

  In the fifth embodiment, the lens surfaces of the fifth surface and the seventeenth surface are aspherical. Table 18 below shows the data of the aspheric surface, that is, the values of the vertex curvature radius R, the conic constant κ, and the aspheric constants A4 to A8.

(Table 18)
κ A4 A6 A8
5th surface 0.043300 8.68000E-07 -3.24000E-09 -2.56000E-12
17th surface 3.855700 1.23000E-05 2.12000E-09 -1.65000E-11

  In the fifth example, the axial air gap d10 between the second lens group G2 and the third lens group G3 and the back focus Bf change during focusing. Table 19 below shows variable intervals at each focal length in the infinitely focused state and the photographing magnification of -0.0333 times.

(Table 19)
Infinite focus state Intermediate shooting distance state
d0 or β ∞ -0.0333
d10 8.65 7.48
Bf 38.10 39.27

  Table 20 below shows values corresponding to the conditional expressions in the fifth embodiment.

(Table 20)
(1) Σdvr / f = 3.11
(2) | (1-βvr) × β3 | = 0.27
(3) f / f2 = -0.17

  FIG. 15A shows an aberration diagram of the fifth embodiment in the infinite focus state, and FIG. 16A shows an aberration diagram of the intermediate shooting distance state. Further, FIG. 15B shows a coma aberration diagram when the blur correction is performed with respect to the rotational blur of 0.70 ° in the infinite focus state in the fifth embodiment, and 0.70 ° in the intermediate shooting distance state. FIG. 16B shows a coma aberration diagram when the shake correction for the rotational shake is performed.

  As is apparent from each aberration diagram, it is clear that in the fifth example, various aberrations are corrected well and the imaging performance is excellent.

[Sixth embodiment]
FIG. 17 is a diagram showing a configuration of an optical system SL6 according to the sixth example of the present application. In the optical system SL6 of FIG. 17, the first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a convex surface facing the object side, and a convex surface facing the object side. It is composed of a cemented lens with an aspheric negative lens L13 having a negative meniscus lens shape, a negative meniscus lens L14 having a concave surface facing the object side, and a biconvex positive lens L15.

  The second lens group G2, in order from the object side, is a cemented lens of a positive meniscus lens L21 having a concave surface facing the object side and a negative meniscus lens L22 having a concave surface facing the object side, a biconcave negative lens L23, and It is composed of a positive meniscus lens L24 having a convex surface facing the object side.

  The third lens group G3 includes, in order from the object side, a positive meniscus lens L31 having a convex surface directed toward the object side, a positive lens L32 having a biconvex shape, a negative meniscus lens L33 having a convex surface directed toward the object side, an aperture stop S, and a biconcave lens. The lens includes a cemented lens of a negative lens L34 having a shape and an aspherical positive lens L35 having a biconvex shape, a positive lens L36 having a biconvex shape, and a positive meniscus lens L37 having a concave surface facing the object side.

  In the sixth example, the image surface I side lens surface (surface number 2) of the negative meniscus lens L11 of the first lens group G1 and the object side lens surface (surface of the positive meniscus lens L14 of the first lens group G1). An antireflection film described later is formed in No. 6).

  It should be noted that the focal length of the entire system is f, and the image blur correction coefficient (ratio of the amount of image movement on the imaging surface to the amount of movement of the moving lens group in shake correction) corrects rotational shake at an angle θ with a K lens. For this, the moving lens group for blur correction may be moved in the direction orthogonal to the optical axis by (f · tan θ) / K. In the sixth example, since the image stabilization coefficient is 0.290 and the focal length is 29.0 (mm), the amount of movement of the second lens group G2 for correcting the rotation blur of 0.70 °. Is 1.22 (mm).

  Table 21 below provides values of specifications of the sixth embodiment.

(Table 21) Sixth Example
f = 29.00
FNO = 1.45
2ω = 74.7
Image height = 21.6
Total length = 134.1

Surface number Curvature radius Surface spacing Refractive index Abbe number object surface ∞ ∞
1 58.989 2.40 1.74100 52.67
2 29.526 6.92
3 72.211 2.10 1.77250 49.60
4 38.041 0.20 1.55389 38.09
* 5 35.056 12.50
6 -43.678 3.98 1.74400 44.78
7 -43.282 0.20
8 91.966 5.50 1.74806 50.00
9 -104.422 3.59
10 -55.000 2.51 1.48749 70.40
11 -41.353 1.50 1.51742 52.31
12 -63.431 0.20
13 -125.764 1.30 1.48749 70.40
14 41.948 0.33
15 43.787 3.35 1.83400 37.16
16 93.370 (d16)
17 40.425 4.23 1.69680 55.52
18 145.955 0.20
19 38.368 6.26 1.69680 55.52
20 -160.073 0.20
21 263.236 1.30 1.61266 44.46
22 26.332 5.00
23 0.000 5.00 Aperture stop S
24 -25.587 1.30 1.78472 25.68
25 43.936 5.35 1.77250 49.60
* 26 -83.081 2.23
27 344.521 4.42 1.75500 52.31
28 -50.243 0.20
29 -102.612 4.73 1.77250 49.61
30 -33.734 (Bf)
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length 1st lens group 1 874.69
Second lens group 10 -150.04
Third lens group 17 43.27

  In the sixth embodiment, the lens surfaces of the fifth surface and the twenty-sixth surface are aspherical. Table 22 below shows the data of aspheric surfaces, that is, the values of the vertex curvature radius R, the conic constant κ, and the aspheric constants A4 to A8.

(Table 22)
κ A4 A6 A8
5th surface 0.155400 2.09390E-07 -8.01120E-10 -1.97890E-12
26th -39.109400 5.05950E-06 2.86350E-08 -4.43890E-11

  In the sixth example, the axial air gap d16 between the second lens group G2 and the third lens group G3 and the back focus Bf change during focusing. Table 23 below shows variable intervals at each focal length in an infinitely focused state and a photographing magnification of -0.0333 times.

(Table 23)
Infinite focus state Intermediate shooting distance state
d0 or β ∞ -0.0333
d16 9.74 8.70
Bf 37.32 38.36

  Table 24 below shows values corresponding to the conditional expressions in the sixth embodiment.

(Table 24)
(1) Σdvr / f = 3.02
(2) | (1-βvr) × β3 | = 0.29
(3) f / f2 = 0.19

  FIG. 18A shows an aberration diagram in the infinite focus state in the sixth embodiment, and FIG. 19A shows an aberration diagram in the intermediate shooting distance state. Further, FIG. 18B shows a coma aberration diagram when the blur correction is performed for the rotational blur of 0.70 ° in the infinite focus state in the sixth embodiment, and 0.70 ° in the intermediate shooting distance state. FIG. 19B shows a coma aberration diagram when the shake correction for the rotational shake is performed.

  As is apparent from each aberration diagram, it is clear that in the sixth example, various aberrations are corrected well and the imaging performance is excellent.

[Seventh embodiment]
FIG. 20 is a diagram showing a lens configuration of an optical system SL7 according to the seventh example of the present application. In the optical system SL7 of FIG. 20, the first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a convex surface facing the object side, and a convex surface facing the object side. A cemented lens with an aspheric negative lens L13 having a negative meniscus lens shape facing, a cemented lens with a positive meniscus lens L14 having a concave surface facing the object side and a negative meniscus lens L15 having a concave surface facing the object side, and on the object side It is composed of a positive meniscus lens L16 having a convex surface.

  The second lens group G2 includes, in order from the object side, a cemented lens of a biconcave negative lens L21 and a positive meniscus lens L22 having a convex surface facing the object side.

  The third lens group G3 includes, in order from the object side, a positive meniscus lens L31 having a convex surface directed toward the object side, a positive lens L32 having a biconvex shape, a negative meniscus lens L33 having a convex surface directed toward the object side, an aperture stop S, and a biconcave lens. The lens includes a cemented lens of a negative lens L34 having a shape and an aspherical positive lens L35 having a biconvex shape, a positive lens L36 having a biconvex shape, and a positive meniscus lens L37 having a concave surface facing the object side.

  In the seventh example, the lens surface (surface number 2) on the image plane I side in the negative meniscus lens L11 of the first lens group G1, and the object side lens in the biconcave negative lens L21 of the second lens group G2. An antireflection film described later is formed on the surface (surface number 11).

  It should be noted that the focal length of the entire system is f, and the image blur correction coefficient (ratio of the amount of image movement on the imaging surface to the amount of movement of the moving lens group in shake correction) corrects rotational shake at an angle θ with a K lens. For this, the moving lens group for blur correction may be moved in the direction orthogonal to the optical axis by (f · tan θ) / K. In the seventh example, since the image stabilization coefficient is 0.30 and the focal length is 30.87 (mm), the amount of movement of the second lens group G2 for correcting the rotation blur of 0.70 °. Is 1.26 (mm).

  Table 25 below provides values of specifications of the seventh embodiment.

(Table 25) Seventh Example
f = 30.87
FNO = 1.45
2ω = 71.3
Image height = 21.6
Total length = 135.0

Surface number Curvature radius Surface spacing Refractive index Abbe number object surface ∞ ∞
1 54.000 2.40 1.74100 52.67
2 30.057 11.01
3 296.733 2.10 1.77250 49.60
4 47.966 0.20 1.55389 38.09
* 5 42.169 7.57
6 -26631.000 6.84 1.74400 44.78
7 -46.891 1.30 1.52599 53.31
8 -139.643 0.20
9 63.943 5.50 1.74806 50.00
10 5875.968 5.10
11 -80.793 1.30 1.48749 70.40
12 51.576 3.05 1.83400 37.16
13 111.029 (d13)
14 39.561 4.26 1.69680 55.52
15 122.864 0.20
16 38.831 6.04 1.69680 55.52
17 -152.489 0.20
18 214.322 1.45 1.61266 44.46
19 24.780 5.00
20 0.000 5.07 Aperture stop S
21 -23.877 1.30 1.78472 25.68
22 40.125 6.00 1.77250 49.60
* 23 -68.316 2.73
24 270.446 6.00 1.75500 52.31
25 -43.519 0.20
26 -92.358 5.31 1.77250 49.61
27 -35.520 (Bf)
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length 1st lens group 1 688.01
Second lens group 11 -146.58
Third lens group 14 43.20

  In the seventh embodiment, the lens surfaces of the fifth surface and the 23rd surface are formed in an aspherical shape. Table 26 below shows aspherical data, that is, the values of the vertex curvature radius R, the conic constant κ, and the aspherical constants A4 to A8.

(Table 26)
κ A4 A6 A8
5th surface -0.678900 -4.81790E-07 -9.78310E-10 1.73750E-13
23rd surface -30.523200 1.70060E-06 4.19410E-08 -5.89620E-11

  In the seventh example, the axial air distance d13 between the second lens group G2 and the third lens group G3 and the back focus Bf change during focusing. Table 27 below shows variable intervals at each focal length in the infinitely focused state and the photographing magnification of -0.0333 times.

(Table 27)
Infinite focus state Intermediate shooting distance state
d0 or β ∞ -0.0333
d13 6.39 5.28
Bf 38.32 39.43

  Table 28 below shows values corresponding to the conditional expressions in the seventh embodiment.

(Table 28)
(1) Σdvr / f = 2.87
(2) | (1-βvr) × β3 | = 0.30
(3) f / f2 = -0.21

  FIG. 21A shows an aberration diagram of the seventh embodiment in the infinite focus state, and FIG. 22A shows an aberration diagram of the intermediate shooting distance state. Further, FIG. 21B shows a coma aberration diagram when the blur correction is performed with respect to the rotational blur of 0.70 ° in the infinite focus state in the seventh embodiment, and 0.70 ° in the intermediate shooting distance state. FIG. 22B shows a coma aberration diagram when the shake correction for the rotational shake is performed.

  As is apparent from the respective aberration diagrams, it is clear that in the seventh example, various aberrations are satisfactorily corrected and the imaging performance is excellent.

[Eighth embodiment]
FIG. 23 is a diagram showing a lens configuration of the optical system SL8 according to the eighth example of the present application. In the optical system SL8 of FIG. 23, the first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface directed toward the object side, a negative meniscus lens L12 having a convex surface directed toward the object side, and a convex surface facing the object side. A negative meniscus lens-shaped aspherical negative lens L13, a positive 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 cemented lens of a biconcave negative lens L21 and a positive meniscus lens L22 having a convex surface facing the object side.

  The third lens group G3 includes, in order from the object side, an aperture stop S, a cemented lens of a biconvex positive lens L31 and a negative meniscus lens L32 having a concave surface facing the object side, a biconcave negative lens L33, and a biconvex lens. The lens includes a cemented lens with a shaped aspherical positive lens L34, a positive meniscus lens L35 having a concave surface facing the object side, and a positive meniscus lens L36 having a concave surface facing the object side.

  In the eighth example, the image surface I side lens surface (surface number 5) of the negative meniscus aspheric negative lens L13 of the first lens group G1 and the image surface of the positive meniscus lens L22 of the second lens group G2 are shown. An antireflection film described later is formed on the lens surface (surface number 12) on the I side.

  It should be noted that the focal length of the entire system is f, and the image blur correction coefficient (ratio of the amount of image movement on the imaging surface to the amount of movement of the moving lens group in shake correction) corrects rotational shake at an angle θ with a K lens. For this, the moving lens group for blur correction may be moved in the direction orthogonal to the optical axis by (f · tan θ) / K. In the seventh embodiment, since the image stabilization coefficient is 0.27 and the focal length is 28.00 (mm), the amount of movement of the second lens group G2 for correcting the rotation blur of 0.70 °. Is 1.26 (mm).

  Table 29 below provides values of specifications of the eighth embodiment.

(Table 29) Eighth Example
f = 28.00
FNO = 1.84
2ω = 76.5
Image height = 21.6
Total length = 124.5

Surface number Curvature radius Surface spacing Refractive index Abbe number object surface ∞ ∞
1 100.000 2.40 1.74100 52.67
2 25.947 5.00
3 46.077 2.10 1.77250 49.60
4 28.597 0.20 1.55389 38.09
* 5 23.872 9.01
6 87.112 3.61 1.90366 31.31
7 18648.952 0.20
8 58.326 3.81 1.90366 31.31
9 250.749 4.00
10 -70.091 1.30 1.60614 37.90
11 48.211 4.02 1.74397 44.85
12 986.837 (d12)
13 0.000 0.10 Aperture stop S
14 59.349 5.59 1.74100 52.67
15 -45.974 1.30 2.00069 25.46
16 -61.044 16.05
17 -25.065 2.50 1.84666 23.78
18 118.919 8.00 1.77250 49.60
* 19 -71.765 1.23
20 -109.608 2.93 1.72916 54.66
21 -45.839 0.20
22 -156.670 4.67 1.80400 46.57
23 -32.339 (Bf)
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length 1st lens group 1 -240.33
Second lens group 10 -152.94
Third lens group 13 41.75

  In the eighth embodiment, the fifth and nineteenth lens surfaces are aspherical. Table 30 below shows the data of the aspheric surface, that is, the values of the vertex curvature radius R, the conic constant κ, and the aspheric constants A4 to A8.

(Table 30)
κ A4 A6 A8
5th surface -0.105300 -1.44211E-06 -3.86598E-09 -6.08176E-13
19th surface 3.354500 1.14404E-05 2.95647E-09 -8.75837E-12

  In the eighth example, the axial air distance d12 between the second lens group G2 and the third lens group G3 and the back focus Bf change during focusing. Table 31 below shows variable intervals at each focal length in an infinitely focused state and a photographing magnification of -0.0333 times.

(Table 31)
Infinite focus state Intermediate shooting distance state
d0 or β ∞ -0.0333
d12 8.08 7.28
Bf 38.20 39.26

  Table 32 below shows values corresponding to the conditional expressions in the eighth embodiment.

(Table 32)
(1) Σdvr / f = 3.17
(2) | (1-βvr) × β3 | = 0.27
(3) f / f2 = -0.18

  FIG. 24A shows an aberration diagram in the infinite focus state in the eighth embodiment, and FIG. 25A shows an aberration diagram in the intermediate shooting distance state. Further, FIG. 24B shows a coma aberration diagram when the blur correction is performed with respect to the rotational blur of 0.70 ° in the infinite focus state in the eighth embodiment, and 0.70 ° in the intermediate focal length state. FIG. 25B shows a coma aberration diagram when the shake correction for the rotational shake is performed. As is apparent from each aberration diagram, it is clear that in the eighth example, various aberrations are corrected well and the imaging performance is excellent.

  Next, an antireflection film (also referred to as a multilayer broadband antireflection film) used in the optical systems SL1 to SL8 (hereinafter collectively referred to as SL) according to each example of the present embodiment will be described.

  FIG. 28 is a diagram illustrating an example of a film configuration of an antireflection film. The antireflection film 101 is composed of seven layers and is formed on the optical surface of the optical member 102 such as a lens. The first layer 101a is formed of aluminum oxide deposited by a vacuum deposition method. Further, a second layer 101b made of a mixture of titanium oxide and zirconium oxide deposited by a vacuum deposition method is further formed on the first layer 101a. Further, a third layer 101c made of aluminum oxide deposited by a vacuum deposition method is formed on the second layer 101b, and titanium oxide and zirconium oxide deposited by a vacuum deposition method are formed on the third layer 101c. A fourth layer 101d made of the mixture is formed. Furthermore, a fifth layer 101e made of aluminum oxide deposited by vacuum deposition is formed on the fourth layer 101d, and titanium oxide and zirconium oxide deposited by vacuum deposition on the fifth layer 101e. A sixth layer 101f made of the mixture is formed.

  Then, a seventh layer 101g made of a mixture of magnesium fluoride and silica is formed on the sixth layer 101f formed in this way by a wet process, and the antireflection film 101 of this embodiment is formed. For the formation of the seventh layer 101g, a sol-gel method which is a kind of wet process is used. The sol-gel method is a method in which a sol obtained by mixing raw materials is made into a non-flowable gel by hydrolysis / polycondensation reaction, etc., and this gel is heated and decomposed to obtain a product, In the production of an optical thin film, a film can be formed by applying an optical thin film material sol on the optical surface of an optical member and forming a gel film by drying and solidifying. The wet process is not limited to the sol-gel method, and a method of obtaining a solid film without going through a gel state may be used.

  Thus, the first layer 101a to the sixth layer 101f of the antireflection film 101 are formed by electron beam evaporation which is a dry process, and the seventh layer 101g which is the uppermost layer is prepared by a hydrofluoric acid / magnesium acetate method. It is formed by the following procedure by a wet process using the prepared sol solution. First, an aluminum oxide layer to be the first layer 101a, a titanium oxide-zirconium oxide mixed layer to be the second layer 101b, a third layer on the lens film formation surface (the optical surface of the optical member 102 described above) in advance using a vacuum deposition apparatus, An aluminum oxide layer to be the layer 101c, a titanium oxide-zirconium oxide mixed layer to be the fourth layer 101d, an aluminum oxide layer to be the fifth layer 101e, and a titanium oxide-zirconium oxide mixed layer to be the sixth layer 101f are formed in this order. And after taking out the optical member 102 from a vapor deposition apparatus, the thing which added the silicon alkoxide to the sol liquid prepared by the hydrofluoric acid / magnesium acetate method is apply | coated by the spin coat method, The magnesium fluoride used as the 7th layer 101g A layer made of a mixture of silica and silica is formed. The reaction formula when prepared by the hydrofluoric acid / magnesium acetate method is shown in the following formula (b).

2HF + Mg (CH3COO) 2 → MgF2 + 2CH3COOH (b)

  The sol solution used for the film formation is used for film formation after mixing raw materials and subjecting to an autoclave at 140 ° C. for 24 hours at a high temperature and pressure. The optical member 102 is completed by heat treatment at 160 ° C. for 1 hour in the air after the seventh layer 101g is formed. By using such a sol-gel method, the seventh layer 101g is formed by depositing particles having a size of several nm to several tens of nm leaving a void.

  The optical performance of the optical member having the antireflection film 101 formed as described above will be described with reference to spectral characteristics shown in FIG.

  The optical member (lens) having the antireflection film according to this embodiment is formed under the conditions shown in Table 33 below. Here, in Table 33, the reference wavelength is λ, and the layers 101a (first layer) to 101g (seventh layer) of the antireflection film 101 when the refractive index (optical member) of the substrate is 1.62, 1.74, and 1.85. The optical film thickness of each layer is determined. In Table 33, aluminum oxide is represented by Al2O3, a mixture of titanium oxide and zirconium oxide is represented by ZrO2 + TiO2, and a mixture of magnesium fluoride and silica is represented by MgF2 + SiO2.

(Table 33)
Substance Refractive index Optical film thickness Optical film thickness Optical film thickness
Medium air 1
7th layer MgF2 + SiO2 1.26 0.268λ 0.271λ 0.269λ
6th layer ZrO2 + TiO2 2.12 0.057λ 0.054λ 0.059λ
5th layer Al2O3 1.65 0.171λ 0.178λ 0.162λ
4th layer ZrO2 + TiO2 2.12 0.127λ 0.13λ 0.158λ
3rd layer Al2O3 1.65 0.122λ 0.107λ 0.08λ
Second layer ZrO2 + TiO2 2.12 0.059λ 0.075λ 0.105λ
1st layer Al2O3 1.65 0.257λ 0.03λ 0.03λ
Refractive index of substrate 1.62 1.74 1.85

  FIG. 29 shows the spectral characteristics when light rays are perpendicularly incident on an optical member in which the reference wavelength λ is 550 nm in Table 33 and the optical film thickness of each layer of the antireflection film 101 is designed.

  From FIG. 29, it can be seen that the optical member having the antireflection film 101 designed with the reference wavelength λ of 550 nm can suppress the reflectance to 0.2% or less over the entire wavelength range of 420 nm to 720 nm. Further, even in the optical member having the antireflection film 101 whose optical film thickness is designed with the reference wavelength λ as d line (wavelength 587.6 nm) in Table 33, the spectral characteristics are hardly affected, and the reference shown in FIG. It has been found that the spectral characteristics are almost the same as when the wavelength λ is 550 nm.

  Next, a modified example of the antireflection film will be described. This antireflection film consists of five layers, and similarly to Table 33, the optical film thickness of each layer with respect to the reference wavelength λ is designed under the conditions shown in Table 34 below. In this modification, the above-described sol-gel method is used for forming the fifth layer.

(Table 34)
Material Refractive index Optical film thickness Optical film thickness Medium Air 1
5th layer MgF2 + SiO2 1.26 0.275λ 0.269λ
4th layer ZrO2 + TiO2 2.12 0.045λ 0.043λ
3rd layer Al2O3 1.65 0.212λ 0.217λ
Second layer ZrO2 + TiO2 2.12 0.077λ 0.066λ
1st layer Al2O3 1.65 0.288λ 0.290λ
Refractive index of substrate 1.46 1.52

  FIG. 30 shows the spectral characteristics when light rays are perpendicularly incident on an optical member having an antireflection film in which the optical film thickness is designed with the refractive index of the substrate being 1.52 and the reference wavelength λ being 550 nm in Table 34. Yes. It can be seen from FIG. 30 that the antireflection film of the present modification has a reflectivity of 0.2% or less over the entire wavelength range of 420 nm to 720 nm. In Table 34, even an optical member having an antireflection film in which each optical film thickness is designed with the reference wavelength λ as the d-line (wavelength 587.6 nm) hardly affects the spectral characteristics, and the spectral characteristics shown in FIG. It is known to have almost the same characteristics as

  FIG. 31 shows the spectral characteristics in the case where the incident angles of the light rays to the optical member having the spectral characteristics shown in FIG. 30 are 30, 45, and 60 degrees, respectively. 30 and 31 do not show the spectral characteristics of the optical member having the antireflection film whose refractive index is 1.46 shown in Table 34, but the refractive index of the substrate is almost equal to 1.52. Needless to say, it has the following spectral characteristics.

  For comparison, FIG. 32 shows an example of an antireflection film formed only by a dry process such as a conventional vacuum deposition method. FIG. 32 shows the spectral characteristics when a light beam is perpendicularly incident on an optical member designed with an antireflection film configured with the refractive index of 1.52 of the same substrate as in Table 34 under the conditions shown in Table 35 below. FIG. 33 shows the spectral characteristics in the case where the incident angles of light rays to the optical member having the spectral characteristics shown in FIG. 32 are 30, 45, and 60 degrees, respectively.

(Table 35)
Material Refractive index Optical film thickness Medium Air 1
7th layer MgF2 1.39 0.243λ
6th layer ZrO2 + TiO2 2.12 0.119λ
5th layer Al2O3 1.65 0.057λ
4th layer ZrO2 + TiO2 2.12 0.220λ
3rd layer Al2O3 1.65 0.064λ
Second layer ZrO2 + TiO2 2.12 0.057λ
1st layer Al2O3 1.65 0.193λ
Refractive index of substrate 1.52

  When comparing the spectral characteristics of the optical member having the antireflection film according to this embodiment shown in FIGS. 29 to 31 with the spectral characteristics of the conventional example shown in FIGS. 32 and 33, the antireflection film has any incidence. It can be seen that the corner also has a lower reflectivity and has a lower reflectivity over a wider band.

  Next, an example in which the antireflection film shown in Table 33 and Table 34 is applied to the first to eighth embodiments will be described.

  In the optical system SL1 of the first example, the refractive index of the negative meniscus lens L11 of the first lens group G1 is nd = 1.74100 as shown in Table 1, and the biconcave shape of the second lens group G2 Since the negative lens L21 has a refractive index of nd = 1.48749, the antireflective film 101 having a refractive index of 1.74 corresponding to the refractive index of the substrate on the image surface side lens surface (surface number 2) of the negative meniscus lens L11. (Refer to Table 33) and use an antireflection film (see Table 34) corresponding to the refractive index of the substrate of 1.46 on the object side lens surface (surface number 11) of the biconcave negative lens L21. Thus, the reflected light from each lens surface can be reduced, and ghost and flare can be reduced.

  In the optical system SL2 of the second example, the refractive index of the negative meniscus lens L11 of the first lens group G1 is nd = 1.74100 as shown in Table 5, and the biconvex shape of the first lens group G1. Since the refractive index of the positive lens L16 is nd = 1.74806, the antireflective film 101 corresponding to the refractive index of the substrate corresponding to 1.74 on the lens surface (surface number 2) on the image plane side of the negative meniscus lens L11. (See Table 33), and an antireflection film (see Table 33) corresponding to a refractive index of the substrate of 1.74 is used on the image surface side (surface number 10) lens surface of the biconvex positive lens L16. As a result, reflected light from each lens surface can be reduced, and ghost and flare can be reduced.

  In the optical system SL3 of the third example, the refractive index of the negative meniscus lens L11 of the first lens group G1 is nd = 1.74100 as shown in Table 9, and the biconcave shape of the second lens group G2 Since the negative lens L21 has a refractive index of nd = 1.48749, the antireflective film 101 having a refractive index of 1.74 corresponding to the refractive index of the substrate on the image surface side lens surface (surface number 2) of the negative meniscus lens L11. (Refer to Table 33) and use an antireflection film (see Table 34) corresponding to the refractive index of the substrate of 1.46 on the object-side lens surface (surface number 10) of the biconcave negative lens L21. Thus, the reflected light from each lens surface can be reduced, and ghost and flare can be reduced.

  In the optical system SL4 of the fourth example, the refractive index of the negative meniscus lens L11 of the first lens group G1 is nd = 1.74100 as shown in Table 13, and the biconvex shape of the first lens group G1 Since the refractive index of the positive lens L16 is nd = 1.77250, the antireflective film 101 corresponding to the refractive index of the substrate corresponding to the refractive index of 1.74 on the lens surface (surface number 2) on the image plane side in the negative meniscus lens L11. (See Table 33), an antireflection film (see Table 33) corresponding to a refractive index of the substrate of 1.74 is used on the image surface side lens surface (surface number 10) of the biconvex positive lens L16. As a result, reflected light from each lens surface can be reduced, and ghost and flare can be reduced.

  In the optical system SL5 of the fifth example, the refractive index of the negative meniscus lens L11 of the first lens group G1 is nd = 1.74100 as shown in Table 17, and the biconcave shape of the second lens group G2 Since the negative lens L21 has a refractive index of nd = 1.55857, the antireflective film 101 having a refractive index of 1.74 corresponding to the refractive index of the substrate on the image surface side lens surface (surface number 2) of the negative meniscus lens L11. (Refer to Table 33) and use an antireflection film (see Table 34) corresponding to a refractive index of the substrate of 1.52 on the object-side lens surface (surface number 8) of the biconcave negative lens L21. Thus, the reflected light from each lens surface can be reduced, and ghost and flare can be reduced.

  In the optical system SL6 of the sixth example, the refractive index of the negative meniscus lens L11 of the first lens group G1 is nd = 1.74100 as shown in Table 21, and the positive meniscus lens of the first lens group G1. Since the refractive index of L14 is nd = 1.74400, the antireflective film 101 (Table 33) whose refractive index of the substrate corresponds to 1.74 on the lens surface (surface number 2) on the image surface side in the negative meniscus lens L11. And an antireflection film (see Table 33) corresponding to a refractive index of the substrate of 1.74 is used on the object-side lens surface (surface number 6) of the positive meniscus lens L14. Reflected light can be reduced, and ghost and flare can be reduced.

  In the optical system SL7 of the seventh example, the refractive index of the negative meniscus lens L11 of the first lens group G1 is nd = 1.74100 as shown in Table 25, and the biconcave shape of the second lens group G2 Since the negative lens L21 has a refractive index of nd = 1.48749, the antireflective film 101 having a refractive index of 1.74 corresponding to the refractive index of the substrate on the image surface side lens surface (surface number 2) of the negative meniscus lens L11. (Refer to Table 33) and use an antireflection film (see Table 34) corresponding to the refractive index of the substrate of 1.46 on the object side lens surface (surface number 11) of the biconcave negative lens L21. Thus, the reflected light from each lens surface can be reduced, and ghost and flare can be reduced.

  In the optical system SL8 of the eighth example, the refractive index of the negative meniscus lens L13 in the first lens group G1 is nd = 1.55389, as shown in Table 29, and the positive meniscus lens in the second lens group G2. Since the refractive index of L22 is nd = 1.74397, the antireflective film 101 corresponding to the refractive index of the substrate of 1.52 on the image side lens surface (surface number 5) in the negative meniscus lens L13 (Table 34). By using an antireflection film (see Table 33) corresponding to a refractive index of the substrate of 1.74 on the lens surface (surface number 12) on the image surface side of the positive meniscus lens L22. The reflected light can be reduced, and ghost and flare can be reduced.

  In the above-described embodiment, the following description can be appropriately adopted as long as the optical performance is not impaired.

  In the present embodiment, an optical system having a three-group configuration is shown, but the above-described configuration conditions and the like can be applied to other group configurations such as a four-group configuration. Further, a configuration in which a lens or a lens group is added closest to the object side, or a configuration in which a lens or a lens group is added closest to the image plane side may be used. The lens group indicates a portion having at least one lens that is separated by an air interval that changes at the time of focusing, or that is separated depending on whether or not it moves so as to have a component substantially orthogonal to the optical axis.

  Alternatively, a single lens group, a plurality of lens groups, or a partial lens group may be moved in the optical axis direction to be a focusing lens group that performs focusing from an object at infinity to a near object. In this case, the focusing lens group can be applied to autofocus, and is also suitable for driving a motor for autofocus (such as an ultrasonic motor). In particular, as described above, the third lens group is preferably a focusing lens group.

  In addition, the lens group or the partial lens group is moved so as to have a component in a direction perpendicular to the optical axis, or is rotated (swayed) in the in-plane direction including the optical axis to reduce image blur caused by camera shake. A vibration-proof lens group to be corrected may be used. In particular, it is preferable that at least a part of the second lens group is an anti-vibration lens group.

  Further, the lens surface may be formed as a spherical surface, a flat surface, or an aspheric surface. It is preferable that the lens surface is a spherical surface or a flat surface 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. 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.

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

  As described above, according to the present invention, it is possible to provide an optical system that further reduces ghosts and flares and has excellent anti-vibration performance, an optical apparatus including the optical system, and a method for manufacturing the optical system. .

SL (SL1 to SL8) Optical system G1 First lens group
G2 Second lens group G3 Third lens group
S Aperture stop I Image plane 1 Digital SLR camera (optical equipment)
101 Antireflection film 101a 1st layer 101b 2nd layer 101c 3rd layer 101d 4th layer 101e 5th layer 101f 6th layer 101g 7th layer 102 Optical member

Claims (20)

From the object side,
A first lens group;
A second lens group having negative refractive power;
The third lens group having a positive refractive power substantially consists of three lens groups ,
An antireflection film is provided on at least one of the optical surfaces of the first lens group and the second lens group, and the antireflection film includes at least one layer formed using a wet process,
The first lens group is fixed in the optical axis direction with respect to the image plane,
The second lens group is composed of a cemented negative lens movably arranged to have a component in a direction orthogonal to the optical axis ,
The distance on the optical axis from the lens surface closest to the image plane of the second lens group at infinity focusing to the paraxial image plane of the entire system is Σdvr, and the focal length of the entire system at infinity focusing is where f is
3.07 ≦ Σdvr / f <5.00
An optical system characterized by satisfying the following conditions. From the object side,
A first lens group;
A second lens group having negative refractive power;
The third lens group having a positive refractive power substantially consists of three lens groups ,
An antireflection film is provided on at least one of the optical surfaces of the first lens group and the second lens group, and the antireflection film includes at least one layer formed using a wet process,
The first lens group is fixed in the optical axis direction with respect to the image plane,
The second lens group is composed of a cemented negative lens movably arranged to have a component in a direction orthogonal to the optical axis ,
The distance on the optical axis from the lens surface closest to the image plane of the second lens group at infinity focusing to the paraxial image plane of the entire system is Σdvr, and the focal length of the entire system at infinity focusing is When f is set , and the lateral magnification of the second lens group at the time of focusing on infinity is βvr, and the lateral magnification of the third lens group at the time of focusing on infinity is β3 , the following expression 2.00 <Σdvr / f <5.00
0.15 <| (1-βvr) × β3 | <0.50
An optical system characterized by satisfying the following conditions. From the object side,
A first lens group;
A second lens group having negative refractive power;
The third lens group having a positive refractive power substantially consists of three lens groups ,
An antireflection film is provided on at least one of the optical surfaces of the first lens group and the second lens group, and the antireflection film includes at least one layer formed using a wet process,
The first lens group is fixed in the optical axis direction with respect to the image plane,
The second lens group is composed of a cemented negative lens movably arranged to have a component in a direction orthogonal to the optical axis ,
The distance on the optical axis from the lens surface closest to the image plane of the second lens group at infinity focusing to the paraxial image plane of the entire system is Σdvr, and the focal length of the entire system at infinity focusing is f, and the focal length of the second lens group is f2.
Then, the following formula 2.00 <Σdvr / f <5.00
−0.35 <f / f2 <−0.07
An optical system characterized by satisfying the following conditions. From the object side,
A first lens group;
A second lens group having negative refractive power;
The third lens group having a positive refractive power substantially consists of three lens groups ,
An antireflection film is provided on at least one of the optical surfaces of the first lens group and the second lens group, and the antireflection film includes at least one layer formed using a wet process,
The first lens group is fixed in the optical axis direction with respect to the image plane,
The second lens group is composed of a cemented negative lens, a negative lens, and a positive lens in order from an object side that is movably disposed so as to have a component in a direction orthogonal to the optical axis .
The distance on the optical axis from the lens surface closest to the image plane of the second lens group at infinity focusing to the paraxial image plane of the entire system is Σdvr, and the focal length of the entire system at infinity focusing is When f is given, the following formula 2.00 <Σdvr / f <5.00
An optical system characterized by satisfying the following conditions. When the lateral magnification of the second lens group at infinity focusing is βvr and the lateral magnification of the third lens group at infinity focusing is β3,
0.15 <| (1-βvr) × β3 | <0.50
The optical system of claim 1 or 4, characterized by satisfying the condition. When the focal length of the entire system at the time of focusing on infinity is f and the focal length of the second lens group is f2, the following equation −0.35 <f / f2 <−0.07
The optical system of claim 1 or 4, characterized by satisfying the condition. When the focal length of the entire system at the time of focusing on infinity is f and the focal length of the second lens group is f2, the following equation −0.35 <f / f2 <−0.07
The optical system according to claim 2 , wherein the following condition is satisfied. The antireflection film is a multilayer film,
Wherein the layer formed using a wet process, an optical system according to any one of claims 1 to 7, characterized in that said a layer of the most surface side among the layers constituting the multilayer film. Wherein when the refractive index of the layer formed using a wet process was nd, optical system according to any one of claims 1 nd is characterized in that 1.30 or less 8. Wherein the optical surface of the antireflection film is provided, an optical system according to any one of claims 1 9, characterized in that when viewed from the aperture stop is a concave lens surface. The optical system according to claim 10 , wherein the lens surface having a concave shape when viewed from the aperture stop is a lens surface on the image plane side. The optical system according to claim 10 , wherein the concave lens surface as viewed from the aperture stop is an object side lens surface. Wherein the optical surface of the antireflection film is provided, an optical system according to claim 1, any one of 12, characterized in that as viewed from the object side is a concave lens surface. The optical system according to claim 13 , wherein the lens surface having a concave shape when viewed from the object side is a lens surface on the image surface side. The optical system according to claim 13 , wherein the concave lens surface when viewed from the object side is a lens surface on the object side. The optical system according to any one of claims 1 to 15 , wherein the aperture stop is disposed closer to the image plane than the second lens group. The optical system according to claim 15 , wherein the aperture stop is disposed in the third lens group. The third lens group, upon focusing on a close object, the optical system according to any one of claims 1 to 17, characterized in that it is arranged to move to the object side. An optical apparatus comprising an optical system according to any one of claims 1 to 18. In order from the object side, an optical system manufacturing method comprising substantially three lenses by a first lens group, a second lens group having a negative refractive power, and a third lens group having a positive refractive power. There,
An antireflection film is provided on at least one of the optical surfaces of the first lens group and the second lens group, and the antireflection film includes at least one layer formed by using a wet process,
The first lens group is disposed so as to be fixed in the optical axis direction with respect to the image plane,
The second lens group is composed of a cemented negative lens, and the second lens group is arranged to move so as to have a component in a direction substantially perpendicular to the optical axis,
The distance on the optical axis from the lens surface closest to the image plane of the second lens group at infinity focusing to the paraxial image plane of the entire system is Σdvr, and the focal length of the entire system at infinity focusing is where f is
3.07 ≦ Σdvr / f <5.00
An optical system manufacturing method, wherein the optical system is arranged so as to satisfy the above condition.

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