JPH1164729A - Zoom lens having camera shake correction function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain high optical performance in spite of compact constitution and to excellently correct an off-axis image point moving error at the time of correcting camera shake by decentering a camera shake correction group constituted of a lens group having positive power in a perpendicular direction to an optical axis so that the camera shake may be corrected, and further satisfying specified conditions. SOLUTION: This lens is equipped with a 1st group Gr1 having the positive power, a 2nd group Gr2 having negative power and a succeeding group constituted of a zoom group; the succeeding group includes a final group GR constituted of a lens group having the negative power and the camera shake correction group Gb adjacent to the object side of the final group and constituted of the lens group having the positive power; and the camera shake is corrected by decentering the camera shake correction group in the perpendicular direction to the optical axis. The respective conditional expressions 1.5<f1/fW<6.0, -1.0<f2/fW<-0.20, -1.5<fB/fR<-0.3 and 0.8<fB/fW<4.0 are satisfied. Provided that f1 and f2 mean the focal distances of the 1st group and the 2nd group, fW means the focal distance of an entire system at a wide angle end, and fB and fR mean the focal distances of the camera shake correction group and the final group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens having a camera shake correction function, and more particularly to a zoom lens having a camera shake correction function suitably used for a single-lens reflex camera.

[0002]

2. Description of the Related Art Various types of zoom lenses having a camera shake correction function have been proposed.
For example, in Japanese Patent Application Laid-Open No. Hei 7-318865,
There has been proposed a zoom lens that performs camera shake correction by moving a positive, positive, and negative fourth lens unit in a direction perpendicular to the optical axis. Japanese Patent Application Laid-Open No. Hei 5-224160 discloses a zoom lens that corrects camera shake by dividing a fifth group of positive, negative, positive, positive, and negative into two groups of negative and positive, and moving the front group. Has been proposed.

[0003]

Since the former zoom lens is a zoom lens for a lens shutter camera, it has a configuration in which a sufficient back focus cannot be secured. Further, the aperture stop exists in the same fourth group as the camera shake correction group. A zoom lens in which a camera shake correction group and an aperture stop exist in the same zoom group has a problem in that a diaphragm driving mechanical component and a camera shake correction driving mechanical component interfere with each other. To avoid this interference, the entire zoom group including the driving mechanical parts becomes large, and as a result, the compactness of the whole zoom lens is impaired, and the camera becomes large. The same applies when the focus group and the aperture stop are in the same zoom group or when the focus group and the camera shake correction group are in the same zoom group. Attempting to avoid interference with the mechanical parts for the camera will lead to an increase in the size of the camera.

In the latter zoom lens, an off-axis image point movement error, which is one of camera shake aberrations, is not satisfactorily corrected.
Even if the image performance at the time of camera shake is guaranteed to some extent, if the distortion is not properly corrected, a large off-axis image point movement error occurs. As a result, when correction is performed for a long time, there is a problem that an off-axis image is blurred. Also, in the latter zoom lens, the front group that moves for camera shake correction is composed of a plurality of lenses, so even if axial lateral chromatic aberration during camera shake correction can be corrected, the camera shake correction group Since the weight is too large, a heavy load is imposed on the camera shake correction driving means. Conversely, the camera shake correction group is a single lens 1
With a zoom lens made up of sheets, the burden on the camera shake correction driving means is minimized, but there is a problem that axial lateral chromatic aberration generated when eccentric driving is performed cannot be corrected. Furthermore, some zoom lenses for which the focusing method is not specified have a camera shake correction function but do not have an appropriate focus solution.
There are zoom lenses for which it is difficult to ensure image performance for a close-range object.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a compact optical system having high optical performance and good off-axis image point movement error during camera shake correction. It is another object of the present invention to provide a zoom lens having a camera shake correction function, which has been corrected to the above.

[0006]

In order to achieve the above object, a zoom lens having a camera shake correction function according to a first aspect of the present invention includes, in order from an object side, a first lens unit having a positive power and a negative lens having a negative power. A second group, and a succeeding group consisting of at least one zoom group, wherein the first group and the second group are arranged so that the distance between the first group and the second group increases during zooming from the wide-angle end to the telephoto end. A second lens unit that moves to the object side, wherein the succeeding lens unit includes a last lens unit located closest to the image side and having a negative power, and an object of the last lens unit. Located adjacent to the side, and
A camera shake correction group composed of a lens group having a positive power, and performing the camera shake correction by decentering the camera shake correction group in a direction perpendicular to the optical axis, and further satisfying the following conditional expression: It is characterized by. 1.5 <f1 / fW <6.0 -1.0 <f2 / fW <-0.20 -1.5 <fB / fR <-0.3 0.8 <fB / fW <4.0 where f1: focal length of the first group, f2: focal length of the second group Distance, fW: focal length of the entire system at the wide-angle end, fB: focal length of the camera shake correction group, fR: focal length of the last group.

According to a second aspect of the present invention, there is provided a zoom lens having a camera shake correction function according to the first embodiment, wherein the camera shake correction group comprises one cemented lens.

According to a third aspect of the present invention, there is provided a zoom lens having a camera shake correction function according to the first aspect of the present invention, wherein
Focusing is performed by moving the group along the optical axis.

According to a fourth aspect of the present invention, there is provided a zoom lens having a camera shake correction function according to the first aspect of the present invention, wherein an aperture stop is provided in a zoom group other than the zoom group including the camera shake correction group.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A zoom lens having a camera shake correction function according to the present invention will be described below with reference to the drawings. FIGS. 1, 8, and 15 are lens configuration diagrams corresponding to the zoom lenses of the first, second, and third embodiments, respectively, and show the lens arrangement at the wide-angle end [W]. Arrows mi (i = 1, 2, 3,...) In each lens configuration diagram schematically show the movement of the i-th lens unit (Gri) during zooming from the wide-angle end [W] to the telephoto end [T]. Is shown in Also, in each lens configuration diagram, the surface with ri (i = 1, 2, 3, ...) is counted from the object side as i
The third surface, the surface marked with * for ri, is an aspheric surface. The axial top surface interval between the groups to which di (i = 1, 2, 3,...) is a variable interval that changes during zooming, of the i-th axial top surface interval counted from the object side. The arrow mD in the lens configuration diagram represents the parallel eccentricity of the camera shake correction group (that is, the movement in the direction perpendicular to the optical axis), and the arrow mF represents the focus movement of the focus group.

The zoom lens according to the first embodiment has, in order from the object side, a first group (Gr1) having a positive power, a second group (Gr2) having a negative power, and a positive group. The zoom lens includes a third lens unit (Gr3), a fourth lens unit (Gr4) having positive power, and a fifth lens unit (Gr5) having negative power. Then, as shown by arrows m1 to m5 in FIG. 1, at the time of zooming from the wide-angle end [W] to the telephoto end [T], the distance between the first unit (Gr1) and the second unit (Gr2) increases. , 2nd group (Gr2) and 3rd group
The distance between (Gr3) and the third group (Gr3) and the fourth group (Gr4)
Are moved so that the distance between the fourth group (Gr4) and the fifth group (Gr5) becomes narrow. The second group (G
An aperture stop (S) that zooms together with the third lens unit (Gr3) between the most image-side surface of r2) and the most object-side surface of the third lens unit (Gr3).
Is arranged.

In the first embodiment, each group is configured as follows in order from the object side. First group (Gr1)
Is composed of a cemented lens of a negative meniscus lens convex on the object side and a biconvex positive lens, and a positive meniscus lens convex on the object side. The second group (Gr2) includes a negative meniscus lens convex on the object side, a biconcave negative lens, a biconvex positive lens, and a negative meniscus lens concave on the object side. The third group (Gr3) includes a biconvex positive lens, a positive meniscus lens convex on the object side, and a negative meniscus lens convex on the object side. The fourth unit (Gr4) includes a cemented lens composed of a biconvex positive lens and a negative meniscus lens convex on the image side. The fifth unit (Gr5) includes a positive meniscus lens convex on the image side, a negative meniscus lens concave on the object side,
It is composed of

In the first embodiment, the second group (Gr2) is a focus group (GF), and the fourth group (Gr4) is a camera shake correction group (Gr).
B). That is, as indicated by the arrow mF (FIG. 1), the second group
By moving (Gr2) to the object side along the optical axis,
Focusing is performed from an object at infinity to an object at a short distance, and the entire fourth unit (Gr4) is eccentrically moved in a direction perpendicular to the optical axis as shown by an arrow mD (FIG. 1). Thus, the camera shake correction is performed.

The zoom lens according to the second embodiment has, in order from the object side, a first unit (Gr1) having a positive power, a second unit (Gr2) having a negative power, and a positive unit having a positive power. The zoom lens includes a third lens unit (Gr3) and a fourth lens unit (Gr4) having negative power. Then, as shown by arrows m1 to m4 in FIG. 8, at the time of zooming from the wide-angle end [W] to the telephoto end [T], the distance between the first lens unit (Gr1) and the second lens unit (Gr2) increases. The distance between the second group (Gr2) and the third group (Gr3) is reduced, and the third group (Gr3)
Each group moves so that the distance between r3) and the fourth group (Gr4) becomes narrow. The most image-side surface of the second group (Gr2) and the third group (Gr2)
An aperture stop (S) that zooms together with the third lens unit (Gr3) is arranged between the third lens unit (Gr3) and the surface closest to the object in 3).

In the second embodiment, each group is configured as follows in order from the object side. First group (Gr1)
Is composed of a cemented lens of a negative meniscus lens convex on the object side and a biconvex positive lens, and a positive meniscus lens convex on the object side. The second group (Gr2) includes a negative meniscus lens convex on the object side, a biconcave negative lens, a biconvex positive lens, and a biconcave negative lens. 3rd group (Gr
3) is composed of a biconvex positive lens, a positive meniscus lens convex on the object side, and a negative meniscus lens convex on the object side. The fourth group (Gr4) includes a cemented lens of a biconvex positive lens and a negative meniscus lens convex on the image side, a positive meniscus lens convex on the image side, and a negative meniscus lens concave on the object side. .

In the second embodiment, the second group (Gr2) is the focus group (GF), and the cemented lens forming a part of the fourth group (Gr4) is the camera shake correction group (Gb). That is, as shown by an arrow mF (FIG. 1), the second unit (Gr2) is moved to the object side along the optical axis, thereby performing focusing from an object at infinity to an object at a short distance. Further, as shown by an arrow mD (FIG. 1), the camera shake correction is performed by eccentrically moving the camera shake correction group (Gb) constituting a part of the fourth group (Gr4) in the direction perpendicular to the optical axis. Configuration.

The zoom lens according to the third embodiment has, in order from the object side, a first unit (Gr1) having a positive power, a second unit (Gr2) having a negative power, and a positive unit. The zoom lens includes a third lens unit (Gr3), a fourth lens unit (Gr4) having positive power, and a fifth lens unit (Gr5) having negative power. Then, as shown by arrows m1 to m5 in FIG.
Group (Gr1) during zooming from the camera to the telephoto end [T]
The distance between the second group (Gr2) and the third group (Gr2)
The distance between the group (Gr3) and the third group (Gr3) and the fourth group (Gr3)
Each group moves so that the distance between the fourth group (Gr4) and the fifth group (Gr5) becomes narrower. The second group
Between the most image-side surface of (Gr2) and the most object-side surface of the third lens unit (Gr3), an aperture stop that zooms together with the third lens unit (Gr3)
(S) is arranged.

In the third embodiment, each group is configured as follows in order from the object side. First group (Gr1)
Is composed of a cemented lens of a negative meniscus lens convex on the object side and a positive meniscus lens concave on the image side, and a positive meniscus lens convex on the object side. The second group (Gr2) includes a negative meniscus lens convex on the object side, a biconcave negative lens,
It is composed of a biconvex positive lens, a negative meniscus lens concave on the object side, and a positive meniscus lens convex on the object side. The third unit (Gr3) includes two biconvex positive lenses and a biconcave negative lens. The fourth unit (Gr4) includes a cemented lens composed of a biconvex positive lens and a negative meniscus lens convex on the image side. The fifth unit (Gr5) includes a positive meniscus lens convex on the image side and a negative meniscus lens concave on the object side.

In the third embodiment, four lenses (r6 to r13) forming a part of the second group (Gr2) are the focus group (Gf), and the fourth group (Gr4) is the camera shake correction group (Gr4). GB). That is,
As shown by an arrow mF (FIG. 15), the focus group (Gf) constituting a part of the second group (Gr2) is moved toward the object side along the optical axis, so that an object at infinity can be moved to a close object. Focusing is performed, and the arrow mD (FIG. 1)
As shown in 5), the entire fourth lens unit (Gr4) is eccentrically moved in a direction perpendicular to the optical axis to perform camera shake correction.

As described above, the first to third embodiments are:
In order from the object side, a first group (Gr1) having positive power,
A second group (Gr2) having negative power, and a subsequent group (Gr3...) Including at least one zoom group;
When zooming from [W] to the telephoto end [T], the first lens unit (Gr.
1st group (Gr2) such that the distance between 1) and the second group (Gr2) increases.
1) and the second group (Gr2) are both zoom lenses that move toward the object side, and the subsequent group (Gr3 ...) is a lens group that is located closest to the image side and has a negative power. A final lens group (GR) and a camera shake correction group (GB or Gb), which is located adjacent to the object side of the final lens group (GR), and includes a lens group having positive power, The camera shake correction is performed by decentering the camera shake correction group (GB or Gb) in the direction perpendicular to the optical axis. This zoom lens configuration having a camera shake correction function (hereinafter referred to as “characteristic zoom configuration”) is suitable for a single-lens reflex camera and has various features as described below.

According to the characteristic zoom structure, the first group (G
Since the distance between r1) and the second lens unit (Gr2) is minimized at the wide-angle end [W], the power arrangement of the entire system is a retrofocus type at the wide-angle end [W]. Therefore, a sufficient back focus can be secured. Conversely, the first group (Gr1) and the second group
(Gr2) is the largest at the telephoto end [T].
In [T], the power arrangement of the entire system is a telephoto type.
Therefore, the total length at the telephoto end [T] can be reduced. Also, unlike the case where the first lens unit (Gr1) is fixed in zooming such as video zoom,
In zooming from [W] to the telephoto end [T], both the first lens unit (Gr1) and the second lens unit (Gr2) move toward the object side, so that the total length of the wide angle end [W] can be reduced.

The conditional expressions which are desirably satisfied in the characteristic zoom configuration will be described. For example, the following conditional expression
It is desirable to satisfy at least one of (1) to (3). Conditional expressions (1) and (2) define conditions for appropriately maintaining the power of the first group (Gr1) and the second group (Gr2).
(3) specifies conditions for appropriately maintaining the back focus.

1.5 <f1 / fW <6.0 (1) -1.0 <f2 / fW <-0.20 (2) 0.85 <LBW / Ymax <2.5 (3) where f1 is the focal point of the first lens unit (Gr1). Distance, f2: focal length of the second lens unit (Gr2), fW: focal length of the entire system at the wide-angle end [W], LBW: back focus at the wide-angle end [W], Ymax: 1 / one of the screen diagonal length 2.

When the value exceeds the upper limit of the conditional expression (1), the first lens unit (Gr1)
Is too weak, the degree of the telephoto type at the telephoto end [T] is weakened, and as a result, the overall length at the telephoto end [T] is increased. On the other hand, the conditional expression
When the value falls below the lower limit of (1), it is advantageous in shortening the total length at the telephoto end [T]. However, in order to secure off-axis light flux at the wide-angle end [W], the diameter of the first lens unit (Gr1) must be reduced. It must be increased, and the power becomes too large, so that it becomes difficult to correct aberrations.

When the value exceeds the upper limit of the conditional expression (2), the second lens unit (Gr2)
Becomes too weak, and the diameter of the first lens unit (Gr1) must be increased in order to secure an off-axis light beam at the wide-angle end [W]. In addition, since the degree of the retrofocus type at the wide angle end [W] is weakened, it becomes difficult to secure a sufficient back focus. On the other hand, the conditional expression
When the value falls below the lower limit of (2), the Petzval sum becomes excessively negative, and it becomes difficult to correct astigmatism and curvature of field. In addition, the degree of the telephoto type at the telephoto end [T] becomes weak, and as a result, the overall length at the telephoto end [T] increases.

When the value exceeds the upper limit of the conditional expression (3), the back focus becomes too long, so that the total length is increased. On the other hand, when the value goes below the lower limit of the conditional expression (3), the back focus becomes too short.
aking lens) It becomes difficult to arrange a mirror.

The following conditional expression (1 ') shows a more desirable conditional range in conditional expression (1). By adopting a configuration that satisfies conditional expression (1 ′), higher optical performance can be realized. 2.5 <f1 / fW <6.0… (1 ')

The following conditional expression (3 ') shows a more desirable conditional range in conditional expression (3). With a configuration that satisfies the conditional expression (3 ′), a more compact zoom lens can be obtained. 0.85 <LBW / Ymax <1.35… (3 ')

In general, a zoom lens for a single-lens reflex camera has a smaller lens diameter as it goes from the object side to the image side, so that the lens weight also becomes smaller. When performing camera shake correction, a camera shake correction drive unit that drives the camera shake correction group is necessary. To reduce the load on the drive unit, it is necessary to make the camera shake correction group small and light. Therefore, it is preferable to use the image side lens group as a camera shake correction group as much as possible. In the first to third embodiments,
Since the lens group located adjacent to the object side of the final group (GR) is used as the image stabilization group (GB or Gb), the load on the image stabilization drive unit is reduced, and the image stabilization drive It is possible to achieve miniaturization of the means.

One of the camera shake aberrations that occurs during camera shake correction is an off-axis image point movement error. This is the amount of overcorrection or undercorrection of off-axis image points that remains when the on-axis image points are corrected by the eccentricity of the camera shake correction group. This aberration mainly depends on the distortion of the focus group (GF or Gf) located closer to the object side than the camera shake correction group (GB or Gb) and the distortion of the camera shake correction group (GB or Gb). ing. Therefore, if the distortion occurring in the camera shake correction group (GB or Gb) is set to an appropriate value,
Off-axis image point movement errors can be reduced. further,
Since the distortion of the entire system has been corrected, the focus group (G
F or Gf), the camera shake correction group (GB or Gb), and the total distortion generated in the final group (GR) can reduce the off-axis image point movement error. From this viewpoint, it is desirable to satisfy at least one of the following conditional expressions (4) and (5).

-1.5 <fB / fR <-0.3 (4) 0.8 <fB / fW <4.0 (5) where fB: focal length of the camera shake correction group (GB or Gb), fR: final group (GR) FW is the focal length of the entire system at the wide-angle end [W].

Conditional expression (4) represents the final group (GR) and the camera shake correction group.
(GB or Gb) are defined as conditions for maintaining a proper power ratio. Exceeding the upper limit of conditional expression (4), the camera shake correction group
Since the power of (GB or Bb) becomes too small compared to the power of the final group (GR), the aberration load in the camera shake correction group (GB or Bb) becomes too small. Therefore, it becomes impossible to obtain the distortion aberration coefficient of the camera shake correction group (GB or Bb) required to cancel the off-axis image point movement error generated at the time of camera shake correction. On the other hand, when the value goes below the lower limit of conditional expression (4), the power of the camera shake correction group (GB or Bb) becomes too large compared to the power of the final group (GR).
(GB or Bb) causes excessive distortion. For this reason, the burden of the distortion of the final group (GR) for suppressing the distortion of the entire system is too small, and the distortion of the entire system cannot be corrected.

Conditional expression (5) defines conditions for keeping the power of the camera shake correction group (GB or Bb) appropriately. Conditional expression
When the value exceeds the upper limit of (5), the power of the camera shake correction group (GB or Bb) becomes too weak, so that the sensitivity at the time of camera shake correction becomes weak. For this reason, while increasing the amount of eccentric movement of the camera shake correction group (GB or Bb), the camera shake correction group (GB or Bb)
The diameter must be increased. Conversely, the conditional expression
If the value is below the lower limit of (5), the power of the camera shake correction group (GB or Bb) becomes too strong, so that the sensitivity at the time of camera shake correction becomes strong. In this case, since the amount of eccentric movement can be reduced, it is not necessary to increase the diameter of the camera shake correction group (GB or Bb), but the position accuracy of the eccentric movement of the camera shake correction group (GB or Bb) must be improved. Therefore, the position accuracy exceeds the performance limit of the position detecting means and the cost increases.

The following conditional expression (5 ') shows a more desirable conditional range in conditional expression (5). By adopting a configuration that satisfies the conditional expression (5 ′), a zoom lens with more accurate position detection accuracy can be obtained. 1.0 <fB / fW <4.0… (5 ')

In the case where the camera shake correction group is composed of one single lens, the number of constituent lenses is minimal, so that the load on the camera shake correction driving means can be minimized. However, when the camera shake correction group is decentered, it is impossible to perform color correction using a single lens alone, so that it is not possible to correct axial lateral chromatic aberration generated at the time of decentering. Further, it is not preferable to configure the camera shake correction group with a plurality of lenses in order to correct the chromatic aberration of the camera shake correction group because the load on the camera shake correction driving unit increases. Therefore,
As in the third embodiment, it is desirable to form a camera shake correction group (GB or Gb) with one cemented lens. If the camera shake correction group is composed of one cemented lens, it is possible to correct the axial lateral chromatic aberration at the time of camera shake correction and to minimize the load on the camera shake correction drive unit.

Generally, different driving means are required for driving for camera shake correction, driving of the aperture stop, and driving of the focus group. For example, when the camera shake correction group and the aperture stop exist in the same zoom group, it is necessary to arrange each driving mechanical component around one lens holding member.
If this arrangement is performed so that the two driving mechanical parts do not physically interfere with each other, the entire zoom group including the driving mechanical parts becomes large as described above, and as a result, the entire zoom lens becomes large. The compactness of the camera is impaired, and the camera becomes larger. Further, not only the arrangement of the driving mechanical parts but also the arrangement of the means for supplying electric power to the driving means are complicated, which is not preferable.

In order to solve the problem caused by the interference between the driving mechanical parts, as in the first to third embodiments, the camera shake correction group, the aperture stop, and the focus group are independent of the zoom group. It is desirable to arrange them separately. If the camera shake correction group, the aperture stop, and the focus group are separately arranged in independent zoom groups, the driving mechanical components are separately arranged in independent zoom groups. As a result, the size of each zoom group and the difficulty of designing each driving mechanical component are reduced, so that the entire zoom lens including the driving unit is made compact without causing interference between the driving mechanical components. It becomes possible.

In the case of the first to third embodiments, the first zoom group (GA) having the aperture stop (S) and the movement of the whole (GF) or part (Gf) along the optical axis The above-described configuration is realized by providing a second zoom group (GF) that performs focusing by using a third zoom group (GB) that performs camera shake correction by parallel eccentricity of the whole (GB) or a part (Gb). ing. In each embodiment, the third group (Gr3) corresponds to the first zoom group (GA), the second group (Gr2) corresponds to the second zoom group (GF), and the fourth group (Gr2) corresponds to the fourth group. The group (Gr4) corresponds to the third zoom group (GB).

The focus group (GF or Gf) is replaced with the camera shake correction group (G
B or Gb), the focus group (G
The object distance to the lens group on the image side of F or Gf) is constant irrespective of focusing. In other words, since the magnification of the camera shake correction group (GB or Gb) is constant regardless of focusing, the fluctuation of aberration up to the camera shake correction group (GB or Gb) is reduced. Therefore, since the effect of camera shake correction does not depend on the object distance, a sufficient camera shake correction effect can be obtained from infinity shooting to close-range shooting.

As described above, in a general single-lens reflex camera zoom lens, since the lens diameter decreases from the object side to the image side, the second group as in the first to third embodiments is reduced. When (Gr2) is used for focusing, the load on the driving means can be reduced as compared with the case where the first lens unit (Gr1) is used for focusing.

Each of the zoom units constituting the first to third embodiments is constituted only by a refraction type lens which deflects an incident light beam by refraction, but is not limited to this.
For example, each zoom group may be configured by a diffractive lens that deflects an incident light beam by diffraction, a refraction / diffraction hybrid lens that deflects an incident light beam by a combination of a diffraction action and a refraction action, or the like.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A zoom lens having a camera shake correction function according to the present invention will be described more specifically with reference to construction data, aberration diagrams, and the like. Examples 1 to 3 given here as examples correspond to the above-described first to third embodiments, respectively, and FIGS. 1, 8, and 15 showing the first to third embodiments correspond to FIGS. 3 shows lens configurations at the wide-angle end [W] of Examples 1 to 3, respectively.

In the construction data of each embodiment, ri (i = 1, 2, 3,...) Is the radius of curvature of the i-th surface counted from the object side, and di (i = 1, 2, 3,. ..) is the i-th shaft upper surface interval counted from the object side (shown here before the eccentricity), and the shaft upper surface interval (variable interval) changed by zooming.
Is from the wide-angle end [W] to the intermediate focal length state [M] to the telephoto end [T].
Is the actual surface spacing between groups. Also, Ni (i =
1, 2, 3,. . . ), Ν i (i = 1, 2, 3,...) Are the refractive index (Nd) for the d-line of the i-th lens counted from the object side,
Abbe number (νd). Each focal length state [W], [M],
Focal length f and F number FNO of the whole system corresponding to [T]
Is shown together with the construction data.

Also, the surface marked with * for the radius of curvature ri is:
It indicates that the surface is constituted by an aspherical surface, and is defined by the following expression (AS) representing the surface shape of the aspherical surface. The aspherical surface data of each aspherical surface is shown together with other data, and Table 1 shows values corresponding to the conditional expressions of each embodiment. X = (C · Y ² ) / {1 + √ (1-ε · Y ² · C ² )} + Σ (Ai · Y ⁱ ) (AS) where, in the equation (AS), X: the optical axis direction The displacement amount from the reference plane, Y: height in the direction perpendicular to the optical axis, C: paraxial curvature, ε: second-order surface parameter, Ai: i-th order aspherical coefficient.

Example 1 (Positive / Negative / Positive / Positive / Negative)

[Aspherical surface data of the sixth surface (r6)] ε = 1.0000 A4 = 0.83645 300 × 10 ^-5 A6 = 0.67353 100 × 10 ^-7 A8 = -0.10566100 × 10 ^-8 A10 = 0.51276 200 × 10 ^-11 A12 = 0.88135000 × 10 ^-15

[Aspherical surface data of the nineteenth surface (r19)] ε = 1.0000 A4 = -0.39985900 × 10 ^-4 A6 = 0.21782000 × 10 ^-6 A8 = 0.95114000 × 10 ^-9 A10 = -0.20385600 × 10 ^-10 A12 = -0.29974600 × 10 ^-12

[Aspherical surface data of the twentieth surface (r20)] ε = 1.0000 A4 = 0.77224600 × 10 ^-4 A6 = 0.72183200 × 10 ^-6 A8 = 0.51068600 × 10 ^-8 A10 = 0.42389 400 × 10 ^-10 A12 = -0.73088800 × 10 ^-12

[Aspherical surface data of the 24th surface (r24)] ε = 1.0000 A4 = -0.45652900 × 10 ^-4 A6 = -0.51530 100 × 10 ^-6 A8 = -0.52845 600 × 10 ^-8 A10 = 0.41459 300 × 10 ^-10 A12 = -0.71354200 × 10 ^-12

[Aspherical surface data of the 25th surface (r25)] ε = 1.0000 A4 = -0.34438900 × 10 ^-4 A6 = -0.52934900 × 10 ^-6 A8 = 0.50113400 × 10 ^-9 A10 = -0.43265 700 × 10 ^-10 A12 = -0.20027900 × 10 ^-14

<< Embodiment 2 (positive / negative / positive / negative) >>

[Aspherical surface data of sixth surface (r6)] ε = 1.0000 A4 = 0.84449900 × 10 ^-5 A6 = 0.63551500 × 10 ^-8 A8 = 0.20154300 × 10 ^-11 A10 = -0.14396 400 × 10 ^-12 A12 = 0.17773000 × 10 ^-14

[Aspherical surface data of the nineteenth surface (r19)] ε = 1.0000 A4 = -0.40326000 × 10 ^-4 A6 = 0.26710500 × 10 ^-6 A8 = 0.12593500 × 10 ^-8 A10 = -0.19817 800 × 10 ^-10 A12 = -0.47458 300 × 10 ^-12

[Aspherical surface data of the twentieth surface (r20)] ε = 1.0000 A4 = 0.82195 200 × 10 ^-4 A6 = 0.74794 100 × 10 ^-6 A8 = 0.70469000 × 10 ^-8 A10 = 0.24450 700 × 10 ^-10 A12 = -0.47794400 × 10 ^-12

[Aspherical surface data of the 24th surface (r24)] ε = 1.0000 A4 = -0.51552400 × 10 ^-4 A6 = -0.42163600 × 10 ^-6 A8 = -0.18955400 × 10 ^-8 A10 = 0.71695600 × 10 ^-10 A12 = -0.17765700 × 10 ^-11

[Aspherical surface data of the 25th surface (r25)] ε = 1.0000 A4 = -0.32518400 × 10 ^-4 A6 = -0.37081400 × 10 ^-6 A8 = 0.25625300 × 10 ^-8 A10 = -0.42716 300 × 10 ^-10 A12 = -0.31376 100 × 10 ^-12

<< Embodiment 3 (positive / negative / positive / positive / negative) >>

[Aspherical surface data of the sixth surface (r6)] ε = 1.0000 A4 = 0.66392800 × 10 ^-5 A6 = -0.35561500 × 10 ^-7 A8 = 0.28951400 × 10 ^-9 A10 = -0.11033500 × 10 ^-11 A12 = 0.54879700 × 10 ^-14

[Aspherical surface data of the 21st surface (r21)] ε = 1.0000 A4 = 0.59076200 × 10 ^-4 A6 = 0.82572900 × 10 ^-6 A8 = -0.12752000 × 10 ^-7 A10 = -0.87916000 × 10 ^-10 A12 = 0.15020400 × 10 ^-11

[Aspherical surface data of the 22nd surface (r22)] ε = 1.0000 A4 = 0.19223400 × 10 ^-3 A6 = 0.43866100 × 10 ^-6 A8 = 0.59818500 × 10 ^-7 A10 = -0.16565500 × 10 ^-8 A12 = 0.15712800 × 10 ^-10

[Aspherical surface data of the 26th surface (r26)] ε = 1.0000 A4 = -0.10553800 × 10 ^-3 A6 = -0.10910900 × 10 ^-5 A8 = 0.43503400 × 10 ^-7 A10 = -0.82295000 × 10 ^-9 A12 = 0.40413 400 × 10 ^-11

[Aspherical surface data of the 27th surface (r27)] ε = 1.0000 A4 = -0.69947800 × 10 ^-4 A6 = -0.87885400 × 10 ^-6 A8 = 0.29904700 × 10 ^-7 A10 = -0.50361 200 × 10 ^-9 A12 = 0.20882900 × 10 ⁻¹¹

[0063]

[Table 1]

FIGS. 2 and 3; FIGS. 9 and 10; FIGS. 16 and 1
FIG. 7 shows the aberration performance of each embodiment before decentering (normal state). 2, 9, and 16 are longitudinal aberration diagrams of the first to third embodiments before decentering (normal state) and in infinity shooting, and FIGS. 3, 10, and 17 are the first to third embodiments. FIG. 14 is a longitudinal aberration diagram of the third embodiment before eccentricity and in a short-distance shooting state (an imaging distance of 1 m). 9, FIG. 9, FIG. 10, FIG. 16 and FIG. 17, [W] is a wide-angle end, [M] is an intermediate focal length state (middle), and [T] is various aberrations at a telephoto end (from the left). In order, spherical aberration, astigmatism,
Distortion; Y ': image height), the solid line (d) represents the aberration with respect to the d-line, the dashed line (SC) represents the sine condition, and the dashed line (DM)
And a solid line (DS) represent astigmatism with respect to the d-line on the meridional surface and the sagittal surface, respectively.

FIGS. 4 to 7, FIGS. 11 to 14, and FIGS. 18 to 21 show the aberration performance of each embodiment before eccentricity (normal state) and after eccentricity (camera shake correction state). 4 and 5; FIG.
FIGS. 12 and 18 are transverse aberration diagrams on the meridional surface before and after eccentricity, at infinity, and in FIGS. 6 and 7; FIGS. FIG. 7 is a lateral aberration diagram before and after decentering, in a close-up shooting state, and on a meridional surface in each embodiment. 4 to 7 show the first embodiment and FIGS.
4 corresponds to the second embodiment, and FIGS. 18 to 21 correspond to the third embodiment, respectively. FIGS. 4, 6; FIGS. 11, 13; 7, FIG. 12, FIG. 14; FIG.
9 and FIG. 21 correspond to the telephoto end [T], respectively. 4 to 7, FIG. 11 to FIG. 14, and FIG.
[A] is the lateral aberration at the image height Y '= + 12,0, -12 in the camera shake correction state of 0.7 degrees {the camera shake correction angle θ of the camera shake correction group θ = 0.7 ° (= 0.0122173 rad)}. FIG. 3B is a lateral aberration diagram at an image height Y ′ = + 12,0 in a normal state.

Table 2 shows the off-axis image point movement error and the on-axis lateral chromatic aberration in each embodiment in the 0.7-degree camera shake correction state. In Table 2, [W] is the wide-angle end, [M] is the intermediate focal length state.
(Middle), [T] is the off-axis image point movement error at the telephoto end (mm)
And on-axis lateral chromatic aberration (mm), and the value in each focal length state is, in order from the top, the image height Y ′ on the meridional surface.
= 12mm (+12,0), Image height on meridional plane Y '=-12
mm (-12,0), image height on sagittal plane Y '= 12mm {(0, + 1
2); The minus side appears symmetrically with the plus side. }. Further, the value of the on-axis lateral chromatic aberration represents the difference between the values of the d-line and the g-line.

[0067]

[Table 2]

[0068]

As described above, according to the first to fourth aspects of the present invention, it has high optical performance while being compact,
In addition, it is possible to realize a zoom lens having a camera shake correction function in which an off-axis image point movement error during camera shake correction is satisfactorily corrected. Further, according to the second aspect, it is possible to satisfactorily correct the axial lateral chromatic aberration during the camera shake correction while minimizing the load on the camera shake correction drive unit. Third
According to the invention, sufficient optical performance can be obtained from infinity photography to short-range photography. According to the fourth aspect, the mechanical components for driving the diaphragm are arranged in a different zoom group from the mechanical components for image stabilization, so that the size can be reduced without causing interference between the mechanical components for driving. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a lens configuration diagram of a first embodiment (Example 1).

FIG. 2 is a longitudinal aberration diagram of Example 1 in an infinity shooting state before decentering.

FIG. 3 is a longitudinal aberration diagram in a close-up shooting state before decentering according to the first embodiment.

FIG. 4 is a meridional lateral aberration diagram before and after decentering, at a wide-angle end, and at infinity, according to the first embodiment.

FIG. 5 is a meridional lateral aberration diagram before and after eccentricity, at a telephoto end, and at infinity in the first embodiment.

FIG. 6 is a meridional lateral aberration diagram before and after decentering, at a wide-angle end, and in a close-up shooting state according to the first embodiment.

FIG. 7 is a meridional lateral aberration diagram before and after decentering, at a telephoto end, and in a close-up shooting state according to the first embodiment.

FIG. 8 is a lens configuration diagram of a second embodiment (Example 2).

FIG. 9 is a longitudinal aberration diagram of Embodiment 2 in an infinity shooting state before decentering.

FIG. 10 is a longitudinal aberration diagram of Example 2 in a short-distance shooting state before decentering.

FIG. 11 is a meridional lateral aberration diagram before and after decentering, at a wide-angle end, and at infinity in Example 2;

FIG. 12 is a meridional lateral aberration diagram before and after decentering, at a telephoto end, and at infinity in Example 2;

FIG. 13 is a meridional lateral aberration diagram before and after eccentricity, at a wide-angle end, and in a close-up shooting state in Example 2.

FIG. 14 is a meridional lateral aberration diagram before and after decentering, at a telephoto end, and in a close-up shooting state according to the second embodiment.

FIG. 15 is a diagram illustrating a lens configuration according to a third embodiment (Example 3).

FIG. 16 is a longitudinal aberration diagram of Embodiment 3 in an infinity shooting state before decentering.

FIG. 17 is a longitudinal aberration diagram of Example 3 in a close-up shooting state before decentering.

FIG. 18 is a meridional lateral aberration diagram before and after decentering, at the wide-angle end, and at infinity in Example 3;

FIG. 19 is a meridional lateral aberration diagram before and after eccentricity, at a telephoto end, and at infinity in Example 3;

FIG. 20 is a meridional lateral aberration diagram before and after decentering, at a wide-angle end, and in a close-up shooting state according to the third embodiment.

FIG. 21 is a meridional lateral aberration diagram before and after eccentricity, at a telephoto end, and in a close-up shooting state in Example 3.

[Explanation of symbols]

 Gr1… First group Gr2… Second group Gr3… Third group S… Aperture stop Gr4… Fourth group Gr5… Fifth group GF… Focus group Gf… Focus group GB… Camera shake correction group Gb… Camera shake correction GR… Final group

Claims (4)

[Claims] 1. A first group having a positive power, a second group having a negative power, and a subsequent group consisting of at least one zoom group are provided in order from the object side, and from a wide-angle end to a telephoto end. A zoom lens in which both the first and second groups move toward the object side so that the distance between the first and second groups increases during zooming. A final group composed of a lens group having a negative power, and a camera shake correction group composed of a lens group having a positive power and located adjacent to the object side of the final group. A zoom lens having a camera shake correction function, wherein the camera shake correction is performed by decentering the camera shake correction group in a direction perpendicular to an optical axis, and further satisfying the following conditional expression: 1.5 <f1 /FW<6.0 -1.0 <f2 / fW <-0.20 -1.5 <fB / fR <-0.3 0.8 <fB / fW <4.0 where f1: focal length of the first group, f2: focal length of the second group, fW: focal length of the entire system at the wide-angle end, fB: focal length of the camera shake correction group FR: focal length of the last group. 2. A zoom lens having a camera shake correction function according to claim 1, wherein said camera shake correction group comprises one cemented lens. 3. A zoom lens having a camera shake correction function according to claim 1, wherein focusing is performed by moving said second group along an optical axis. 4. A zoom group other than the zoom group including the camera shake correction group has an aperture stop.
A zoom lens having the image stabilization function described in the above.