JP2000321494A - Variable power optical system provided with vibration- proof function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a variable power optical system provided with vibration- proof function which obtains a still image by optically correcting the blur of a photographic image when the variable power optical system vibrates. SOLUTION: This variable power optical system has a 1st lens group L1 with positive refracting power which is fixed at the time of power variation and focusing, a 2nd lens group L2 with negative refracting power with a power varying function, a 3rd lens group L3 with positive refracting power, a 4th lens group L4 with positive refracting power which corrects an image plane varying as the power varies and has a focusing function in this order from the object side. In this case, the 3rd lens group L3 is moved at right angles to the optical axis to correct a blur of a photographic image when the variable power optical system vibrates and the 2nd lens group L2 consists of a negative meniscus lens 21 which has a very strong concave surface to the image plane side, a negative lens 22, a positive lens 23, and a negative lens 24 in this order from the object side and satisfies a condition of 0.05<|f2/ft|<0.07, where ft is the focal length of the whole system at the telephoto end and f2 is the focal length of the 2nd lens group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable power optical system having an image stabilizing function, and more particularly to a variable power optical system by moving a part of a lens group of the variable power optical system in a direction perpendicular to an optical axis. Suitable for video cameras, silver halide photography cameras, electronic still cameras, etc., which stabilize the captured image by optically correcting the blur of the captured image when the camera vibrates (tilt) to obtain a still image. The present invention relates to a variable power optical system having a vibration function.

[0002]

2. Description of the Related Art When an image is taken from a moving object such as a car or an aircraft in progress, vibration is transmitted to an image taking system, resulting in camera shake and blurring of the taken image.

Conventionally, various anti-vibration optical systems having a function of preventing blurring of a captured image have been proposed.

For example, in Japanese Patent Application Laid-Open No. 56-21133, some optical members are moved in a direction to cancel the vibrational displacement of the image due to the vibration in response to the output signal from the detecting means for detecting the vibration state in the optical device. By doing so, the image is stabilized. Japanese Patent Application Laid-Open No. Sho 61-223819 discloses a photographing system in which a variable apex angle prism is arranged closest to the object side, thereby stabilizing an image by changing the apex angle of the variable apex angle prism in accordance with the vibration of the imaging system. ing.

[0005] Japanese Patent Application Laid-Open No. 1-116619 and Japanese Patent Application Laid-Open
In Japanese Patent Application Laid-Open No. 124452/1994, a still image is detected by detecting vibration of a photographing system using an acceleration sensor or the like, and vibrating some lens groups of the photographing system in a direction perpendicular to an optical axis according to a signal obtained at this time. Have gained.

In Japanese Patent Application Laid-Open No. Hei 7-128619, a third lens unit of a four-unit variable magnification optical system comprising a lens unit having positive, negative, positive and positive refractive powers is arranged in order from the object side. It is composed of two lens groups of power, and vibration is prevented by vibrating the positive lens group.

In Japanese Patent Application Laid-Open No. Hei 7-199124, the entire third lens group of a four-unit variable magnification optical system including lens groups having positive, negative, positive, and positive refractive powers is sequentially oscillated from the object side. It is carried out.

On the other hand, in Japanese Patent Application Laid-Open No. 5-60974, a variable power optical system of four groups consisting of lens units having positive, negative, positive, and positive refractive powers is arranged in order from the object side. The overall length of the lens is shortened as a telephoto-type negative lens.

[0009]

Generally, an image stabilizing optical system is disposed in front of a photographing system, and a part of the movable lens group of the image stabilizing optical system is vibrated to eliminate blurring of a photographed image and obtain a still image. The method has a problem that the entire apparatus becomes large and a moving mechanism for moving the movable lens group becomes complicated.

In an optical system that performs image stabilization using a variable apex angle prism, there is a problem that the amount of eccentric magnification chromatic aberration increases during image stabilization, especially on the long focal length side.

On the other hand, in an optical system for performing image stabilization by decentering some lenses of the photographing system in a direction perpendicular to the optical axis, there is an advantage that no extra optical system is required for image stabilization. However, there is a problem in that a space for a lens to be moved is required, and the amount of eccentric aberration generated during image stabilization increases.

When the entire third lens group of the four-unit variable power optical system including lenses having positive, negative, positive, and positive refractive powers is moved in a direction perpendicular to the optical axis, the vibration is reduced. When the three lens groups are formed of a telephoto type including a positive lens and a meniscus-shaped negative lens for shortening the overall length, eccentric aberration, particularly eccentric distortion, occurs. When this is used for a video camera or the like that shoots a moving image, there is a problem in that a problem such as noticeable deformation of an image during image stabilization occurs.

If the zoom ratio is further increased, there is a problem that a change in peripheral light amount becomes conspicuous during image stabilization.

According to the present invention, a relatively small and light lens group constituting a part of a variable power optical system is moved in a direction perpendicular to the optical axis.
The zoom lens system is configured to correct image blurring when the zooming optical system is vibrated (tilted), and by appropriately configuring the lens group for correcting image blurring, the size of the entire apparatus can be reduced. It is an object of the present invention to provide a variable power optical system having an image stabilizing function that satisfactorily corrects eccentric aberration when the lens group is decentered while simplifying the mechanism and reducing the load on a driving unit.

[0015]

Means for Solving the Problems The first invention of claim 1 is:
A first lens unit having a fixed positive refractive power, a second lens unit having a negative refractive power having a variable power function, a third lens unit having a positive refractive power, and a variable power during zooming and focusing in order from the object side. A variable power optical system having a fourth lens unit having a positive refractive power and having a focusing function and correcting an image plane which fluctuates due to magnification, wherein the third lens unit is moved in a direction perpendicular to the optical axis. The second lens group includes a meniscus negative twenty-first lens and a negative twenty-second lens having a strong concave surface on the image surface side in order from the object side when the variable magnification optical system vibrates. 0.05 <| f2 / ft | <where the focal length at the telephoto end of the entire system is ft and the focal length of the second lens group is f2. It is characterized by satisfying the conditional expression of 0.07.

According to a second aspect of the present invention, there is provided a first lens unit having a positive refractive power fixed during zooming and focusing in order from the object side, and a second lens unit having a negative refractive power having a zooming function. A third lens unit having a positive refractive power, a variable power optical system having a fourth lens unit having a positive refractive power and having a focusing function while correcting an image plane that varies due to zooming; The lens group is moved in the direction perpendicular to the optical axis to correct the blur of the captured image when the variable power optical system vibrates, and the third lens group is moved from the most object side lens surface of the variable power optical system. When the distance to the lens surface closest to the object side is LS and the focal length at the telephoto end of the entire system is ft, the following conditional expression is satisfied: 0.42 <| LS / ft | <0.59 I have.

[0017]

FIG. 1 is a schematic view showing a paraxial refractive power arrangement according to the present invention, FIG. 2 is an explanatory view of the optical principle of a vibration-proof optical system according to the present invention, and FIG. FIG. 4 is an explanatory diagram of a light amount change. FIG. 4 is a sectional view of a lens at a wide angle end according to Numerical Embodiment 1 of the present invention.

In the drawing, L1 is a first group having a positive refractive power, L2 is a second group having a negative refractive power, and L3 is a third group having a positive refractive power. In the present embodiment, the third lens unit L3 is moved in the direction perpendicular to the optical axis to correct the blur of the captured image when the variable power optical system vibrates (tilts). L4 is a fourth unit having a positive refractive power. SP denotes an aperture stop, which is arranged in front of the third lens unit L3. G is a glass block such as a face plate. IP is an image plane. Reference numeral FP denotes a flare cut stop, which is arranged between the third and fourth units, and is moved on the optical axis with zooming.

In this embodiment, at the time of zooming from the wide-angle end to the telephoto end, the second unit is moved to the image plane side as indicated by the arrow in FIG. It is moved and corrected.

Also, a rear focus system is adopted in which the fourth unit is moved on the optical axis to perform focusing. A solid line curve 4a and a dotted line curve 4b of the fourth lens group shown in the same figure show the image plane fluctuation caused by zooming from the wide-angle end to the telephoto end when focusing on an object at infinity and an object at a short distance, respectively. The movement locus for correction is shown. The first and third units are fixed during zooming and focusing.

In the present embodiment, the fourth unit is moved to correct the image plane fluctuation caused by zooming, and the fourth unit is moved to perform focusing. In particular, as shown by curves 4a and 4b in the same figure, the zoom lens is moved so as to have a convex locus toward the object side when zooming from the wide-angle end to the telephoto end. Thus, the space between the third and fourth units is effectively used, and the overall length of the lens is effectively reduced.

In this embodiment, for example, when focusing from an object at infinity to an object at a short distance at the telephoto end, the fourth unit is moved forward as indicated by a straight line 4c in FIG.

In this embodiment, as compared with the conventional so-called four-unit zoom lens, in which the first unit is extended and focused, the rear focus method is used to prevent the performance deterioration due to the eccentric error of the first unit. First while doing
This effectively prevents the effective lens diameter of the group from increasing. By arranging the aperture stop immediately before the third lens unit, aberration variation due to the movable lens unit is reduced, and the distance between the lens units in front of the aperture stop is shortened, so that the diameter of the front lens can be easily reduced. are doing.

In the present invention, the third lens unit L3 is moved in the direction perpendicular to the optical axis for image stabilization to correct image blur when the variable power optical system vibrates. As a result, compared to the conventional anti-vibration optical system, anti-vibration is performed without newly adding an optical member such as a lens group or a variable apex prism for anti-vibration.

Next, the optical principle of an image stabilizing system for correcting a blur of a photographed image by moving a lens group in a direction perpendicular to the optical axis in the variable power optical system according to the present invention will be described with reference to FIG.

As shown in FIG. 2A, the optical system has a fixed group Y
1. It is composed of three parts of an eccentric group Y2 and a fixed group Y3, and it is assumed that an object point P on the optical axis sufficiently far from the lens is formed as an image point p at the center of the imaging plane IP. .

Now, the entire optical system including the imaging plane IP is shown in FIG.
As shown in (B), if the camera is tilted momentarily due to camera shake,
The object point P also instantaneously moves to the image point p 'and becomes a blurred image.

On the other hand, when the eccentric group Y2 is moved in the direction perpendicular to the optical axis, the image point p moves to p ″ as shown in FIG.
The moving amount and direction depend on the power arrangement, and are expressed as the eccentric sensitivity of the lens group.

In FIG. 2B, the image point p 'shifted by the camera shake is returned to the original image forming position p by moving the eccentric group Y2 in the direction perpendicular to the optical axis by an appropriate amount. As shown in (D), camera shake correction, that is, image stabilization is performed.

Now, the amount of movement of the shift lens group (eccentric group) Y2 required to correct the optical axis by θ ° is Δ, the focal length of the entire optical system is f, and the sensitivity of the shift lens group Y2 to eccentricity is TS.
Then, the movement amount Δ is given by the following equation: Δ = f · tan (θ) / TS.

Now, the eccentric sensitivity TS of the shift lens group Y2
Is too large, the amount of movement Δ becomes a small value, and the amount of movement of the shift lens group necessary for image stabilization can be made small. However, it is difficult to perform appropriate image stabilization control, and correction remains. In particular, video cameras and digital still cameras use C
Since the image size of an image sensor such as a CD is smaller than that of a silver halide film and the focal length for the same angle of view is shorter, the shift amount Δ of the shift lens group for correcting the same angle becomes smaller.

Therefore, if the accuracy of the mechanism (mechanism) is almost the same, the uncorrected portion on the screen becomes relatively large.

On the other hand, if the eccentric sensitivity TS is too small, the amount of movement of the shift lens group necessary for control becomes large, and the driving means such as an actuator for driving the shift lens group also becomes large.

In the present invention, the eccentricity sensitivity TS of the third lens unit is set to an appropriate value by setting the refractive power arrangement of each lens unit to an appropriate value. An optical system with less load on driving means such as an actuator has been achieved.

Further, when the lens group inside such an optical system is shifted in a direction perpendicular to the optical axis to perform image stabilization, the peripheral light amount distribution is asymmetric with respect to the shift direction. For this reason, at the time of moving image shooting, the direction of camera shake changes over time, so that the amount of peripheral light also changes over time, thereby causing flickering around the screen.

This will be described with reference to FIG.

Assuming that the correction angle of the optical axis is θ, the deflection H of the light beam on the lens surface closest to the object side of the optical system is equal to the correction lens L3 formed by the optical system closer to the object side than the correction lens (third group) L3. Assuming that the distance from the image HP to the lens surface closest to the object side of the optical system is DS, H = DS · tan θ as shown in FIG.

FIGS. 3 (B), 3 (C) and 3 (D) show changes in the peripheral light amount during image stabilization. 3B is a normal state, FIG. 3C is a correction state in which the optical system faces downward, and FIG.
(D) is a correction state in which the optical system faces upward. In the correction state, the light amount changes because the light beam width W of the light beam changes. The amount of change increases as the amount H of fluctuation of the central ray passing through the first surface increases.

Therefore, in order to reduce the change in the amount of light, the distance from the first surface to the third lens unit L3 to be shifted must be reduced to reduce the distance DS.

For this purpose, it is preferable to increase the refractive power of the second lens unit and to reduce the amount of movement required for zooming the second lens unit.

Therefore, in the first invention, the relationship between the focal length f2 of the second lens unit and the focal length ft at the telephoto end of the entire system is set so as to satisfy 0.05 <| f2 / ft | <0.07 (1). By doing so, the amount of movement of the second lens group necessary for zooming is reduced.

When the refracting power of the second lens unit is increased beyond the lower limit of the conditional expression (1), the moving amount of the second lens unit at the time of zooming is reduced, but the Petzval sum increases in the negative direction as a whole. It is not preferable because it becomes difficult to correct the curvature of field. Conversely, if the value exceeds the upper limit of (1), the amount of movement of the second lens unit at the time of zooming becomes large, and the entire lens system is not reduced in size.

If a high zoom ratio such as 20 times or more is used under the conditional expression (1), it becomes difficult to correct lateral chromatic aberration accompanying zooming.

In the present invention, the second lens group includes, in order from the object side, a meniscus negative 21st lens, a negative 22nd lens, a positive 23rd lens, and a negative 24th lens having a strong concave surface on the image plane side. By reducing the symmetry before and after the second lens unit, the achromatic effect of the principal point is enhanced, and the chromatic aberration of magnification is effectively corrected.

In the first aspect of the present invention, when the focal length of the twenty-fourth lens is f24, it is preferable to satisfy the following condition: 1.2 <| f24 / f2 | <2.5 (2)

Conditional expression (2) is mainly for effectively correcting the difference in magnification color number. If the focal length of the twenty-fourth lens is too small below the upper limit of conditional expression (2), the effect of correcting chromatic aberration will be insufficient. Conversely, if the lower limit is exceeded, it becomes difficult to correct distortion at the wide-angle end.

In the second aspect of the present invention, in order to reduce a change in the amount of peripheral light during image stabilization, the light from the lens surface closest to the object side of the photographing system (variable optical system) is set at the time of image stabilization of the third lens group. When the distance to the lens surface closest to the object side of the portion moving perpendicular to the axis is LS, and the focal length at the telephoto end of the entire system is ft, the following condition is satisfied: 0.42 <| LS / ft | <0.59 (3) We are trying to satisfy the formula.

If the upper limit of conditional expression (3) is exceeded, the change in the amount of light during image stabilization becomes more conspicuous when the magnification is increased. Conversely, in order to exceed the lower limit, it is necessary to increase the refractive power of the second lens unit. And it becomes difficult to correct aberration fluctuations during zooming.

Incidentally, in the first invention, if the conditional expression (3) of the second invention is satisfied, it is possible to better correct the aberration change at the time of image stabilization.

The variable power optical system having the image stabilizing function according to the first and second aspects of the present invention can be realized by satisfying the above-mentioned conditions. In order to achieve performance, it is desirable to satisfy at least one of the following conditions.

(A-1) The third lens group includes, in order from the object side, a positive 31st lens and a meniscus negative 32nd lens with a strong concave surface facing the image side.

(A-2) The third lens group is composed of, in order from the object side, a positive 31st lens, a meniscus-shaped negative 32nd lens having a strong concave surface on the image side, and a positive 33rd lens. That is.

By providing a meniscus-shaped negative lens having a strong concave surface on the image surface side in the third lens group, the entire third lens group is configured as a telephoto configuration to reduce the distance between the principal points of the second lens group and the third lens group. This shortens the overall length of the lens.

When such a meniscus-shaped negative lens is provided, a positive distortion occurs on the lens surface, which causes a large eccentric distortion at the time of image stabilization. In order to reduce this decrease, the distortion generated in the entire third lens group may be reduced.

In this embodiment, distortion is corrected in the third lens group while maintaining a certain telephoto configuration by arranging a positive 33rd lens on the image side of the negative 32nd meniscus lens. In addition, the occurrence of eccentric distortion generated when the third lens group is shifted to perform image stabilization is reduced.

(A-3) The thirty-first lens has an aspherical surface on both sides.

By providing aspherical surfaces on both lens surfaces of the thirty-first lens, spherical aberration is suppressed by the third lens unit,
Eccentric coma generated during image stabilization is reduced.

(A-4) When the focal lengths of the 32nd lens and the entire third lens group are f32 and f3, respectively, 1.2 <| f32 / f3 | <1.8 (4) To be satisfied.

Conditional expression (4) is for achieving the miniaturization of the entire optical system by making the third lens group a telephoto type.

If the refractive power of the 32nd lens in the third lens unit is increased beyond the lower limit of the conditional expression (4), it is advantageous for shortening the total length of the lens, but the Petzval sum increases in the negative direction, and the image becomes negative. It is not good because it becomes difficult to correct the surface curvature. Conversely, if the lower limit is exceeded, the overall length will be insufficiently reduced.

(A-5) Appropriately setting the sensitivity of the shift group for image stabilization greatly affects the image stabilization performance.

Therefore, the focal length of the entire system at the wide-angle end is represented by f
w, when the focal length of the third lens unit is f3, it is preferable to satisfy the following condition: 3.5 <f3 / fw <5.5 (5) Thus, the sensitivity of the shift lens group is set to an appropriate value while shortening the overall length of the lens.

If the refractive power of the third lens group is increased beyond the lower limit of the conditional expression (5), the sensitivity of the shift lens group becomes too large, and if the mechanical precision is not strict, the remaining correction during vibration reduction becomes large. Not so good.

Conversely, if the upper limit is exceeded and the refractive power of the third lens group is weakened, the shift amount of the third lens group required for image stabilization becomes large, or the overall length of the lens becomes large, which is good. Absent.

(A-6) It is necessary to correct distortion and astigmatism in the third lens group while maintaining the telephoto configuration of the third lens group, and to maintain good optical performance during image stabilization. When the focal length of the 33 lens is f33 and the focal length of the third lens unit is f3, it is preferable to satisfy the following condition: 1.2 <f33 / f3 <2.0 (6)

If the refractive power of the 33rd lens becomes too strong below the lower limit of the conditional expression (6), the telephoto property of the third lens group is not maintained and the effect of shortening the entire length is lost, which is not good.
Conversely, if the upper limit is exceeded, the correction of distortion and astigmatism in the third lens group becomes insufficient, and the optical performance during image stabilization deteriorates.

(A-7) In order to achieve a reduction in the change in light quantity during image stabilization, the diameter of the aperture is made smaller on the telephoto side during zooming so as to restrict the central light flux so that the peripheral light quantity is relatively increased. It is good to do.

(A-8) It is preferable to introduce an aspherical surface into the second lens unit in order to correct astigmatism and distortion during zooming.

(A-9) Since the third lens group moves for vibration reduction, it is necessary to increase the lens diameter accordingly.

Therefore, it is desirable to dispose a fixed stop on the object side or the image plane side of the third lens group in order to prevent excessive on-axis light flux from entering. In the present embodiment, a fixed stop is arranged between the third lens unit and the fourth lens unit to effectively use a space and prevent unnecessary light beams from entering.

Next, numerical examples of the present invention will be described. In the numerical examples, Ri is the radius of curvature of the ith lens surface in order from the object side, Di is the ith lens thickness and air spacing in order from the object side, and Ni and νi are the ith lens in order from the object side. Are the refractive index and Abbe number of the glass. Table 1 shows the relationship between the above-described conditional expressions and the numerical examples.

The aspheric surface has an X-axis in the optical axis direction, an H-axis in a direction perpendicular to the optical axis, a positive traveling direction of light, R is a paraxial radius of curvature,
When A, B, C, D, and E are aspherical coefficients

[0073]

(Equation 1)

This is represented by the following equation. Numerical family example 1 f = 1 ~ 20.59 Fno = 1.85 ~ 3.17 2ω = 63.0 ° ~ 3.4 ° R 1 = 11.517 D 1 = 0.35 N 1 = 1.846660 ν 1 = 23.8 R 2 = 6.297 D 2 = 1.43 N 2 = 1.603112 ν 2 = 60.6 R 3 = -92.841 D 3 = 0.05 R 4 = 5.730 D 4 = 0.75 N 3 = 1.696797 ν 3 = 55.5 R 5 = 15.090 D 5 = Variable R 6 = 9.859 D 6 = 0.20 N 4 = 1.834000 ν 4 = 37.2 R 7 = 1.328 D 7 = 0.68 R 8 = 13.880 D 8 = 0.17 N 5 = 1.834807 ν 5 = 42.7 R 9 = 15.420 D 9 = 0.07 R10 = 2.620 D10 = 0.69 N 6 = 1.846660 ν 6 = 23.8 R11 = -4.562 D11 = 0.04 R12 = -3.405 D12 = 0.17 N 7 = 1.804000 ν 7 = 46.6 R13 = 5.388 D13 = Variable R14 = Aperture D14 = 0.30 R15 = 2.335 (Aspheric) D15 = 0.93 N 8 = 1.583126 ν 8 = 59.4 R16 = 25.000 (aspheric surface) D16 = 0.10 R17 = 3.731 D17 = 0.20 N 9 = 1.846660 ν 9 = 23.8 R18 = 2.179 D18 = 0.40 R19 = 8.449 D19 = 0.57 N10 = 1.516330 ν10 = 64.1 R20 = -5.658 D20 = 0.50 R21 = fixed aperture D21 = variable R22 = 3.043 D22 = 0.70 N11 = 1.516330 ν11 = 64.1 R23 = -2.736 D23 = 0.17 N12 = 1.805181 ν12 = 25.4 R24 = -5.522 D24 = 0.75 R25 = ∞ D25 = 0.82 N13 = 1.516330 ν13 = 64.2 R26 = ∞ ＼focal length 1.00 6.15 20.59 variable interval＼ D5 0.18 4.44 5.65 D13 5.83 1.56 0.36 D21 2.17 0.65 2.44 Spherical coefficient R15 k = -3.775970e + 00 B = 3.18486e-02 C = -4.89959e-03 D = -1.95138e-03 E = 1.32137e-03 R16 k = -1.05769e + 02 B = 7.80185e-03 C = -3.881520e-03 D = 0.00000e + 00 E = 0.00000e + 00 Numerical example 2 f = 1 ~ 22.55 Fno = 1.85 ~ 3.98 2ω = 63.0 ° ~ 3.1 ° R 1 = 12.297 D 1 = 0.38 N 1 = 1.846660 ν 1 = 23.8 R 2 = 6.682 D 2 = 1.52 N 2 = 1.603112 ν 2 = 60.6 R 3 = -120.232 D 3 = 0.05 R 4 = 6.114 D 4 = 0.88 N 3 = 1.696797 ν 3 = 55.5 R 5 = 16.311 D 5 = variable R 6 = 12.864 D 6 = 0.20 N 4 = 1.834000 ν 4 = 37.2 R 7 = 1.344 D 7 = 0.74 R 8 = -3.873 (aspheric) D 8 = 0.20 N 5 = 1.814740 ν 5 = 37.0 R 9 = -75.000 D 9 = 0.07 R10 = 2.319 D10 = 0.70 N 6 = 1.846660 ν 6 = 23.8 R11 = -3.711 D11 = 0.04 R12 = -3.139 D12 = 0.17 N 7 = 1.806098 ν 7 = 40.9 R13 = 3.131 D13 = Variable R14 = Aperture D14 = 0.38 R15 = 2.489 (Aspheric) D15 = 0.85 N 8 = 1.583126 ν 8 = 59.4 R16 = 25.305 (Aspheric) D16 = 0.10 R17 = 5.216 D17 = 0.20 N 9 = 1.846660 ν 9 = 23.8 R18 = 2.738 D18 = 0.33 R19 = 12.789 D19 = 0.55 N10 = 1.516330 ν10 = 64.1 R20 = -4.292 D20 = 0.50 R21 = fixed aperture D21 = variable R22 = 3.060 D22 = 0.70 N11 = 1.516330 ν11 = 64.1 R23 = -2.829 D23 = 0.17 N12 = 1.846660 12 = 23.8 R24 = -5.411 D24 = 0.75 R25 = ∞ D25 = 0.82 N13 = 1.516330 ν13 = 64.2 R26 = ∞ ＼ Focal length 1.00 6.08 22.55 Variable interval＼ D5 0.18 4.78 6.08 D13 6.25 1.65 0.35 D21 2.79 1.17 3.07 Aspheric coefficient R8 k = 2.64239e + 00 B = 6.73912e-03 C = 2.62124e-04 D = 3.71477e-03 E = 0.00000e + 00 R15 k = -3.31127e + 00 B = 2.18668e-02 C = -1.38403e- 03 D = -1.75691e-03 E = 1.28774e-03 R16 k = 4.00000e + 01 B = 5.94845e-03 C = -1.05613e-04 D = 0.00000e + 00 E = 0.00000e + 00 Numerical example 3 f = 1 ~ 22.34 Fno = 1.85 ~ 3.55 2ω = 63.0 ° ~ 3.1 ° R 1 = 11.948 D 1 = 0.35 N 1 = 1.846660 ν 1 = 23.8 R 2 = 6.382 D 2 = 1.43 N 2 = 1.603112 ν 2 = 60.6 R 3 = -87.012 D 3 = 0.05 R 4 = 5.919 D 4 = 0.75 N 3 = 1.696797 ν 3 = 55.5 R 5 = 16.039 D 5 = Variable R 6 = 11.021 D 6 = 0.20 N 4 = 1.834000 ν 4 = 37.2 R 7 = 1.300 D 7 = 0.67 R 8 = -3.802 D 8 = 0.17 N 5 = 1.834807 ν 5 = 42.7 R 9 = 13.482 D 9 = 0.07 R10 = 2.600 D10 = 0.69 N 6 = 1.846660 ν 6 = 23.8 R11 = -3.471 D11 = 0.04 R12 = -3.006 D12 = 0.17 N 7 = 1.804000 ν 7 = 46.6 R13 = 5.101 D13 = Variable R14 = Aperture D14 = 0.25 R15 = 2.375 (Aspheric) D15 = 1.07 N 8 = 1.583126 ν 8 = 59.4 R16 = 25.150 (Non Surface) D16 = 0.05 R17 = 3.556 D17 = 0.20 N 9 = 1.846660 ν 9 = 23.8 R18 = 2.148 D18 = 0.42 R19 = 8.588 D19 = 0.57 N10 = 1.516330 ν10 = 64.1 R20 = -8.185 D20 = 0.37 R21 = Fixed aperture D21 = Variable R22 = 3.393 D22 = 0.70 N11 = 1.516330 ν11 = 64.1 R23 = -2.437 D23 = 0.17 N12 = 1.805181 ν12 = 25.4 R24 = -4.575 D24 = 0.75 R25 = ∞ D25 = 0.82 N13 = 1.516330 ν13 = 64.2 R26 = ＼ ＼ Distance 1.00 6.65 22.34 Variable interval＼ D5 0.17 4.66 5.93 D13 6.10 1.61 0.35 D21 2.29 0.53 2.46 Aspherical coefficient R15 k = -3.44285e + 00 B = 2.91925e-02 C = -4.87054e-03 D = -1.33859e-03 E = 1.43602e-03 R16 k = -8.39783e + 00 B = 8.77241e-03 C = -6.49371e-03 D = 2.03005e-03 E = 0.00000e + 00

[0075]

[Table 1]

[0076]

As described above, according to the present invention, by moving the relatively small and light lens group constituting a part of the variable power optical system in the direction perpendicular to the optical axis, the variable power optical system is vibrated. By configuring so as to correct the image blurring caused by (tilting), the eccentricity when the lens group is decentered while reducing the size of the entire apparatus, simplifying the mechanism, and reducing the load on the driving means. It is possible to achieve a variable power optical system having an anti-vibration function in which the amount of generated aberration is reduced and the eccentric aberration is corrected well.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a paraxial refractive power arrangement of a variable power optical system according to the present invention.

FIG. 2 is an explanatory view of the optical principle of a vibration isolation system according to the present invention.

FIG. 3 is a diagram for explaining a change in light amount during image stabilization.

FIG. 4 is a sectional view of a lens at a wide angle end according to Numerical Embodiment 1 of the present invention.

FIG. 5 is a diagram illustrating various aberrations at a wide-angle end according to Numerical Embodiment 1 of the present invention.

FIG. 6 is a diagram illustrating various aberrations at the telephoto end according to Numerical Embodiment 1 of the present invention.

FIG. 7 is a diagram showing various aberrations at the telephoto end according to Numerical Embodiment 1 of the present invention.

FIG. 8 is a diagram illustrating various aberrations at the wide-angle end according to Numerical Example 2 of the present invention.

FIG. 9 is a diagram showing various aberrations at the telephoto end according to Numerical Example 2 of the present invention.

FIG. 10 is a diagram showing various aberrations at the telephoto end according to Numerical Example 2 of the present invention;

FIG. 11 is a diagram illustrating various aberrations at a wide angle end according to Numerical Example 3 of the present invention.

FIG. 12 is a diagram illustrating various aberrations at the telephoto end according to Numerical Example 3 of the present invention.

FIG. 13 is a diagram illustrating various aberrations at the telephoto end according to Numerical Example 3 of the present invention.

[Explanation of symbols]

 L1 First lens unit L2 Second lens unit L3 Third lens unit L4 Fourth lens unit SP diaphragm FP fixed diaphragm IP image plane d d-line g g-line ΔM meridional image plane ΔS sagittal image plane

Claims (6)

[Claims] 1. A first lens group having a fixed positive refractive power, a second lens group having a negative refractive power having a zooming function, and a second lens group having a positive refractive power during zooming and focusing in order from the object side. A variable power optical system having a third lens group and a fourth lens group having a positive refractive power and having a focusing function and correcting an image plane that fluctuates due to zooming, wherein the third lens group is perpendicular to the optical axis. The second lens group is moved in the direction to correct the blur of the captured image when the variable power optical system vibrates, and the second lens group is a meniscus-shaped negative 21st lens having a strong concave surface on the image surface side in order from the object side; The negative 22nd lens,
When the focal length at the telephoto end of the whole system is ft and the focal length of the second lens group is f2, 0.05 <| f2 / ft | <0. A zoom optical system having an anti-vibration function, which satisfies the following conditional expression. 2. The anti-vibration function according to claim 1, wherein a conditional expression of 1.2 <| f24 / f2 | <2.5 is satisfied, where f24 is a focal length of the 24th lens. Variable power optical system having 3. A first lens unit having a fixed positive refractive power, a second lens unit having a negative refractive power having a zooming function, and a second lens unit having a positive refractive power when zooming and focusing in order from the object side. A variable power optical system having a third lens group and a fourth lens group having a positive refractive power and having a focusing function and correcting an image plane that fluctuates due to zooming, wherein the third lens group is perpendicular to the optical axis. To correct the blur of the captured image when the variable power optical system vibrates, from the most object side lens surface of the variable power optical system to the most object side lens surface of the third lens group. Where LS is the distance of LS and ft is the focal length at the telephoto end of the entire system, the following conditional expression is satisfied: 0.42 <| LS / ft | <0.59 Variable power optical system. 4. The third lens unit according to claim 1, wherein the third lens group includes a positive first lens in order from the object side, and a meniscus negative second lens having a strong concave surface facing the image surface side.
Or a variable power optical system having the anti-vibration function according to 3. 5. When the focal lengths of the 32nd lens and the entire third lens group are f32 and f3, respectively, a conditional expression of 1.2 <| f32 / f3 | <1.8 is satisfied. 4. A variable power optical system having an image stabilizing function according to claim 1. 6. A variable-magnification optical system having an image stabilizing function according to claim 1, further comprising an aperture stop that varies an opening diameter according to a focal length of the entire system during zooming. system.