JPH11237550A - Variable power optical system provided with vibration proof function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the eccentricity generation amount of a lens group while miniaturizing a device and simplifying a mechanism or the like, by moving a 32nd group in the vertical direction to an optical axis, correcting the shake of photographing images when a variable power optical system is vibrated and making the focus distances of the 32nd group and a third group and the focus distance of the entire system satisfy specified conditions. SOLUTION: This system is provided with the first group L1 of positive refractive power, the second group L2 of negative refractive power provided with a variable power function, the third group L3 of the positive refractive power and the forth group L4 of the positive refractive power provided with a correction function for correcting an image surface fluctuated by variable power and a focusing function. The third group L3 is provided with the 31st group L31 of the negative refractive power and the 32nd group L32 of the positive refractive power. Then, the 32nd group L32 is moved in the vertical direction to the optical axis, the shake of the photographing images when this variable power optical system is vibrated is corrected, and at the time of defining the focus distances of the 32nd group L32 and the third group L3 respectively as f32 and f3 and the focus distance of the wide angle end of the entire system as fW, 8<f3/fW<25 and 0.3<|f32/f3|<0.75 are satisfied.

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. Cameras, video cameras, electronic still cameras, and 3-CCD compatible electronic devices that 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 reduction function suitable for a camera or the like.

[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 photographed image at this time have been proposed.

For example, in Japanese Patent Publication No. 56-21133, some optical members are moved in a direction to cancel the vibrational displacement of an image due to vibration in response to an output signal from a detecting means for detecting a vibration state in an optical device. This stabilizes the image.

In Japanese Patent Application Laid-Open No. 61-223819, in a photographing system in which a refraction type variable apex angle prism is arranged closest to the subject, the apex angle of the refraction type variable apex angle prism is changed according to the vibration of the imaging system. The image is deflected to stabilize the image.

Japanese Patent Publication No. 56-34847, Japanese Patent Publication No. 5
In JP-A-7-7414, an optical member spatially fixed to vibration is arranged in a part of a photographing system, and a photographed image is deflected by utilizing a prism effect generated by vibration of the optical member. A still image is obtained on the image plane.

[0007] Japanese Patent Application Laid-Open Nos.
In Japanese Patent Application Laid-Open No. -125211, vibration of a photographing system is detected using an acceleration sensor or the like, and according to a signal obtained at this time,
There is also a method of obtaining a still image by vibrating a part of a lens group of a photographing system in a direction orthogonal to an optical axis.

In Japanese Patent Laid-Open Publication No. Hei 7-128619, a first positive refractive power which is fixed during zooming and focusing in order from the object side.
Group, a second group of negative refractive power having a zooming function, an aperture stop,
A zoom lens having four lens groups, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power having both a correction function and a focusing function for correcting an image plane which fluctuates due to zooming. An optical system, wherein the third unit includes two lens units, a first unit having a negative refractive power and a second unit having a positive refractive power. The third unit is moved in a direction perpendicular to the optical axis. The shake of the captured image when the variable magnification optical system vibrates is corrected.

In Japanese Patent Application Laid-Open No. 7-199124,
Vibration reduction is performed by vibrating the entire third unit of the variable power optical system having four groups of negative, positive, and positive refractive powers.

[0010]

In general, an anti-vibration optical system is disposed in front of a photographing system, and a part of the movable lens group of the anti-vibration optical system is vibrated to eliminate a blur of a photographed image and obtain a still image. The method has a problem that the whole apparatus becomes large and a moving mechanism for moving the movable lens group becomes complicated.

There is also a problem that the amount of decentering aberration generated when the movable lens group is vibrated increases, and the optical performance is greatly reduced.

An optical system that performs image stabilization using a variable apex angle prism has a problem that the amount of chromatic aberration of eccentric magnification increases during image stabilization, especially on the long focal length side (telephoto side).

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

Also, in a variable magnification optical system having a four-unit configuration including four lens units having positive, negative, positive, and positive refractive powers, a method of performing image stabilization by moving the entire third unit in a direction perpendicular to the optical axis. In this case, when the size of an image pickup device such as a CCD is reduced in order to reduce the size of the entire optical system, there is a problem that the accuracy with respect to the eccentric position of the third group for vibration reduction becomes too severe. .

Particularly, in recent years, even in consumer video cameras, the 3-CCD system has been adopted in some cameras in order to improve image quality. However, the 3-CCD compatible positive,
In a variable power optical system having four groups of negative, positive and positive refractive powers,
If the entire third lens unit is moved in the direction perpendicular to the optical axis and vibrated, the sensitivity of the third lens unit for correcting the optical axis for image stabilization is too small, and the movement of the correction lens unit is reduced. There is a problem that the amount becomes too large and the whole optical system becomes too thick.

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, and an image obtained when the variable power optical system vibrates (tilts) is obtained. By configuring so as to correct the blur, the amount of eccentricity generated when the lens group is decentered is reduced while the size of the entire apparatus is reduced, the mechanism is simplified, and the load on the driving unit is reduced. It is an object of the present invention to provide a variable power optical system having an anti-vibration function for correcting aberrations well and increasing the sensitivity of the eccentric lens group for anti-vibration, thereby reducing the size of the entire optical system.

[0017]

According to a first aspect of the present invention, there is provided a variable power optical system having an anti-vibration function, comprising: (1-1) a fixed positive refractive power at the time of zooming and focusing in order from the object side. The first lens group, the second lens group having a negative refractive power having a zooming function, the third lens group having a positive refractive power, and both a correcting function for correcting an image plane that fluctuates due to zooming and a focusing function. A variable power optical system having four lens groups of a fourth group having a positive refractive power, wherein the third group is composed of at least two of a 31st group having a negative refractive power and a 32nd group having a positive refractive power. A lens group, and moving the 32nd group in a direction perpendicular to the optical axis to correct blurring of a captured image when the variable power optical system vibrates;
When the focal lengths of the second and third lens units are f32 and f3, respectively, and the focal length at the wide-angle end of the whole system is fW, 8 <f3 / fW <25 (a) 0.3 <| f32 / f3 | <0.75 ‥‥‥ (b) is satisfied.

In particular, (1-1-1) the third lens group is arranged in order from the object side to the 31st lens group and the 32nd lens group.

(1-1-2) The third lens unit includes, in order from the object side, a 31st lens unit having a negative refractive power, a 32nd lens unit having a positive refractive power, and a third lens unit.
Having three lens groups of three groups. And so on.

The variable power optical system having the image stabilizing function according to the second aspect of the present invention includes: (1-2) a first group having a fixed positive refractive power, which is fixed during zooming and focusing in order from the object side; A second group of negative refractive power having a function, a third group of positive refractive power, and a second group of positive refractive power having both of a correction function and a focusing function for correcting an image plane fluctuating by zooming. A variable power optical system having four lens groups of four groups, wherein the third group has two or more lens groups including a 31st group having a negative refractive power and a 32nd group having a positive refractive power; The third
The two units are moved in the direction perpendicular to the optical axis to correct the blur of the photographed image when the variable magnification optical system vibrates, the focal length at the wide angle end of the entire system is fW, and the focal length at the wide-angle end from the final lens surface to the imaging surface is When the back focus at the wide-angle end when the optical member having no refracting power is removed is bfW, the condition 3 <bfW / fW <6ｆ (b3) is satisfied.

In particular, (1-2-1) when the focal lengths of the 32nd lens group and the third lens group are f32 and f3, respectively, 8 <f3 / fW <25 (b1) 0.3 <| f32 /F3|<0.75‥‥‥(b2).

The variable power optical system having the image stabilizing function according to the third aspect of the present invention includes: (1-3) a first group having a fixed positive refractive power which is fixed at the time of zooming and focusing in order from the object side; A second group of negative refractive power having a function, a third group of positive refractive power, and a second group of positive refractive power having both of a correction function and a focusing function for correcting an image plane fluctuating by zooming. A variable power optical system having four lens units including four lens units, wherein the third unit includes a 31st unit having a negative refractive power,
The 32nd lens having a positive refractive power as a whole having the above negative lens
Group, and a third group including one positive lens,
It is characterized in that the two units are moved in the direction perpendicular to the optical axis to correct the blur of the photographed image when the variable magnification optical system vibrates.

In particular, (1-3-1) when the focal lengths of the second and third lens units are f32 and f3, respectively, and the focal length at the wide-angle end of the whole system is fW, 8 <f3 / fW <25 ° {(C1) 0.3 <| f32 / f3 | <0.75} (c2).

In another configuration (1-1), (1-2) or (1-3), the focal length of the second lens unit is f2, and the focal lengths of the entire system at the wide-angle end and the telephoto end are fW, When fT,

[0025]

(Equation 2) It is characterized by satisfying certain conditions.

Incidentally, the first, second and third inventions are collectively referred to as "the present invention" hereinafter.

[0027]

FIG. 1 is a schematic view showing a paraxial refractive power arrangement according to the present invention, and FIGS. 2 to 4 are lens sectional views at the wide-angle end of Numerical Examples 1 to 3 of the present invention.

In the figure, L1 is a first lens unit having a positive refractive power, L2 is a second lens unit having a negative refractive power, L3 is a third lens unit having a positive refractive power, and a 31st lens unit L31 having a negative refractive power. And the 32nd of positive refractive power
It has two or more lens groups of group L32.

In the first to third numerical examples, the 32nd lens unit L32 is moved in the direction perpendicular to the optical axis as shown by the arrow 3 to correct the blur of the photographed image when the variable magnification optical system vibrates (tilts).

L4 is a fourth lens unit having a positive refractive power. SP denotes an aperture stop, which is arranged in front of the third lens unit L3, in the third lens unit, or between the third lens unit and the fourth lens unit. G is a glass block such as a face plate. IP is an image plane.

As shown in FIG. 1, in the present embodiment, at the time of zooming from the wide-angle end to the telephoto end, the second lens unit is moved to the image plane side as indicated by an arrow, and the image plane fluctuation caused by zooming is changed to the fourth lens unit. Is moved for correction.

Further, a rear focus system is employed 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 for 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. Thereby, 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 shown by a straight line 4c in FIG.

The zoom lens according to the present embodiment employs a zoom system in which a virtual image formed by a combined system of the first and second units is formed on the photosensitive surface by the third and fourth units.

In the present embodiment, the performance degradation due to the eccentricity error of the first group is prevented by adopting the rear focus method as described above in comparison with a conventional so-called four-group zoom lens in which the first group is extended and focused. First while doing
This effectively prevents the effective lens diameter of the group from increasing.

Then, the aperture stop is placed immediately before the third lens unit, or
By arranging in the group or between the third and fourth groups, aberration fluctuation due to the movable lens group is reduced, and the distance between the lens groups ahead of the aperture stop is shortened to reduce the diameter of the front lens. Is easily achieved.

In the numerical embodiments 1 and 3 of FIGS. 2 and 4 of the present invention, the third unit L3 is composed of two lens units, a 31st unit having a negative refractive power and a 32nd unit having a positive refractive power. Numerical example 2 of 3
Then, the third lens unit L3 is divided into a 31st lens unit L31 having a negative refractive power, a 32nd lens unit L32 having a positive refractive power, and a 33rd lens unit L having a positive refractive power.
It comprises 33 lens groups.

In the present embodiment, the third group may be composed of three or more lens groups. Then, the 32nd lens group of the third lens group is moved in the direction perpendicular to the optical axis for image stabilization to correct image blurring when the variable magnification 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 blurring of a photographed image by moving a lens group in a direction perpendicular to the optical axis in a variable power optical system according to the present invention will be described with reference to FIG.

As shown in FIG. 14A, the optical system is composed of three parts, a fixed group Y1, an eccentric group Y2, and a fixed group Y3, and the object point P on the optical axis sufficiently separated 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.
Assuming that the object point P is instantaneously tilted due to camera shake as shown in FIG. 4B, the object point P also instantaneously moves to the image point p ', resulting in 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. 14C, and the amount and direction of the movement depends on the power arrangement. It is expressed as the eccentric sensitivity of the lens group.

Therefore, the image point p 'shifted by the camera shake in FIG. 14B 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 small, the movement amount Δ becomes a large value, the movement amount of the shift lens group necessary for image stabilization becomes too large, and the lens diameter increases.

In particular, a shooting lens for a 3-CCD video camera requires a space on the image plane side for arranging a prism for color separation, and therefore has a longer back focus than a normal single-plate shooting lens. Is required. For this reason, the positive refractive power of the third lens unit becomes weaker than the positive refractive power of the fourth lens unit, and the sensitivity of the third lens unit in the direction perpendicular to the optical axis decreases.

Therefore, if the entire third lens unit is moved in the direction perpendicular to the optical axis direction to perform vibration, the amount of movement of the third lens unit becomes too large. If an attempt is made to increase the eccentric sensitivity of the third lens group by using a currently-used four-group zoom lens having a positive, negative, positive, and positive refractive power as a photographing lens for a video camera, It becomes necessary to increase the refracting power of the third lens group, and it becomes difficult to secure the back focus, and the lens becomes unsuitable for the 3-CCD system.

Therefore, in the present invention, the third lens unit is divided into two or more lens units, a first lens unit having a negative refractive power and a second lens unit having a positive refractive power. By increasing the eccentric sensitivity.
A compact anti-vibration optical system that is compatible with CCD has been achieved.

Here, conditional expression (a1) according to the first invention,
The condition (a2), the conditional expressions (b1) and (b2) according to the second invention, and the conditional expressions (c1) and (c2) according to the third invention mainly correspond to the third group in the four-unit zoom lens having the configuration described above. This is for appropriately setting the focal length (refractive power) of the second lens group and the 32nd lens group to increase the sensitivity of the shift lens group while ensuring a sufficiently long back focus.

When the refractive power of the third lens unit is increased beyond the lower limits of the conditional expressions (a1), (b1) and (c1), it is advantageous for shortening the overall length of the lens, but it becomes difficult to secure the back focus. Not so good. Conditional expressions (a1) and (b)
If the refractive power of the third lens unit is weakened beyond the upper limits of 1) and (c1), it becomes difficult to shorten the entire length of the lens.

The conditional expressions (a2), (b2) and (c2) relate to the arrangement of the refractive powers of the two lens units of the third unit, the 31st unit and the 32nd unit. Conditional expressions (a2), (b2),
If the refractive power of the 32nd lens group increases beyond the lower limit of (c2), the eccentricity sensitivity also increases, and the remaining amount of image stabilization due to the influence of mechanical errors increases. Conversely, if the refractive power of the 32nd lens group becomes smaller than the upper limit value, the amount of movement of the 32nd lens group required for image stabilization becomes too large, and members such as actuators for driving the lens group become large, which is not good.

In the second aspect of the present invention, by satisfying the conditional expression (b3), the present invention is suitably applied to a 3-CCD compatible video camera.

If the back focus exceeds the lower limit of conditional expression (b3) and the back focus becomes too short, there is no space for inserting a color separation prism or the like. In addition, the refractive power of the 31st lens group becomes too strong, and it becomes difficult to maintain the optical performance when the 32nd lens group is shifted and shake-proofed.

In the first, second and third aspects of the present invention, the total length of the lens is reduced by satisfying conditional expression (4).

If the refractive power of the second lens unit becomes too strong beyond the lower limit value of the conditional expression (4), it is advantageous for shortening the overall length of the lens, but it is necessary to correct the variation of the field curvature and the distortion over the entire zoom range. Is not good because it becomes difficult. If the refractive power of the second lens unit becomes too weak beyond the upper limit value of the conditional expression (4), the amount of movement of the second lens unit required for zooming becomes too large.

In the first, second, and third aspects of the present invention, in order to sufficiently correct the chromatic aberration of magnification over the entire zoom range, the second lens unit includes a meniscus having a strong concave surface directed toward the image surface in order from the object side. Negative lens, negative lens with both lens surfaces concave, positive lens,
And it is good to comprise with a negative lens. Further, when the back focus is extended for the 3-CCD, the refractive power of the fourth lens unit increases, and the height of the axial ray passing through the fourth lens unit increases, so that spherical aberration easily occurs. Is preferably composed of at least one negative lens and two positive lenses, and has at least one aspheric surface.

Next, a numerical embodiment 1 of FIG. 2 will be described. In FIG. 2, the third lens unit is composed of a 31st lens unit having a fixed negative refractive power in order from the object side, and a 32nd lens unit having a positive refractive power shifted vertically to the optical axis for image stabilization. Are composed of a negative lens and a positive lens with both lens surfaces being concave, the 32nd lens unit is composed of a meniscus-shaped negative lens with a strong concave surface facing the image surface side, and two positive lens with both lens surfaces being convex.

By providing an aspherical surface on at least one surface of each of the 31st and 32nd units, various aberrations generated in each lens unit are reduced, and deterioration of optical performance during image stabilization is suppressed. .

In this embodiment, aspherical surfaces are introduced into the lens surface closest to the object side in the 31st lens unit and the lens surface closest to the image plane in the 32nd lens unit, so as to reduce spherical aberration and coma generated in each lens unit. As a result, the eccentric aberration, particularly the eccentric coma generated at the time of image stabilization is corrected well.

The position of the aspherical surface may be different on each group. Further, in order to correct the chromatic aberration of magnification and the field curvature due to the eccentricity, it is desirable that the chromatic aberration is corrected as much as possible by the shift group alone and the Petzval sum is reduced.

Therefore, it is effective to include at least one negative lens in the shift lens group (the 32nd group) in order to correct chromatic aberration and to reduce Petzval sum. At this time, in order to keep the chromatic aberration of the entire system favorable, it is preferable to include at least one positive lens in the third group in addition to the 32nd group.

Next, a second embodiment of FIG. 3 will be described. In FIG. 3, the third lens unit is a third lens unit having a fixed negative refractive power from the object side, a second lens unit having a positive refractive power shifted in a direction perpendicular to the optical axis for image stabilization, and a weak refractive power (the third lens unit). (Fifth or more times the focal length f3).

The 31st unit is composed of one negative lens, the 32nd unit is composed of a negative lens and a positive lens having both convex surfaces, and the 33rd unit is composed of a cemented lens of a positive lens and a negative lens. An aspherical surface is introduced to the lens surface closest to the image plane in the 32nd lens group to form a third lens unit.
The spherical aberration and coma in the two groups are reduced to suppress the occurrence of eccentric coma that occurs during image stabilization.

In this embodiment, the chromatic aberration of the entire third lens unit is corrected by making the entire third lens unit have a weak refractive power, and the influence of the position error of the third lens unit is reduced.

Next, a numerical example 3 of FIG. 4 will be described. In FIG. 4, the third lens unit is composed of, in order from the object side, a 31st lens unit having a fixed negative refractive power and a 32nd lens unit having a positive refractive power shifted in a direction perpendicular to the optical axis for image stabilization. The 31st lens unit includes a negative lens having both concave lens surfaces and a positive lens having both lens surfaces convex. The 32nd lens unit includes a meniscus negative lens having a convex surface facing the object side and a positive lens having both convex lens surfaces. It consists of a lens.

Aspherical surfaces are provided on the object-side lens surface of the 31st lens unit and the image-side lens surface of the 32nd lens unit to prevent a decrease in optical performance during image stabilization.

Next, numerical examples of the present invention will be described. In the numerical examples, Ri is the radius of curvature of the i-th lens surface in order from the object side, Di is the i-th lens thickness and air spacing from the object side, and Ni and νi are the i-th lens surfaces in order from the object side. The refractive index and Abbe number of glass. Also, R29 to R33 in Numerical Embodiment 1 and R in Numerical Embodiment 2
Reference numerals 28 to R32 and R26 to R30 in Numerical Example 3 indicate optical filters, face plates, and the like, but these may be omitted as necessary.

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 aspheric coefficients, respectively,

[0070]

(Equation 3) It is represented by the following equation. " ^EX " means 10-X. Table 1 shows the relationship between the above-described conditional expressions and various numerical values in the numerical examples.

[0071]

[Outside 1]

[0072]

[Outside 2]

[0073]

[Outside 3]

[0074]

[Table 1]

[0075]

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. When the lens group is decentered while reducing the overall size of the apparatus, simplifying the mechanism, and reducing the load on the driving means, the configuration is such that image blurring caused by (tilting) is corrected. Variable power optics with anti-vibration function that minimizes the amount of eccentricity, satisfactorily corrects eccentric aberrations, and increases the sensitivity of the eccentric lens group for anti-vibration, miniaturizing the entire optical system A system can be achieved.

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

FIG. 3 is a sectional view of a lens at a wide angle end according to Numerical Example 2 of the present invention.

FIG. 4 is a sectional view of a lens at a wide-angle end according to a third numerical embodiment of the present invention.

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

FIG. 6 is a diagram showing 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 showing 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 showing 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.

FIG. 14 is an explanatory diagram of the optical principle of the vibration isolation system according to the present invention.

[Explanation of symbols]

 L1 First group L2 Second group L3 Third group L4 Fourth group L31 First group L32 Second group L33 Third group SP Aperture IP Image plane d d-line g g-line ΔM Meridional image plane ΔS Sagittal image plane

Claims (8)

[Claims] 1. 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 third lens unit having a positive refractive power during zooming and focusing in order from the object side. A variable power optical system having four lens units of a fourth lens unit having a positive refractive power and having both a correction function and a focusing function of correcting an image plane that fluctuates due to zooming; The third group includes two or more lens groups, a 31st group having a negative refractive power and a 32nd group having a positive refractive power.
The second group is moved in the direction perpendicular to the optical axis to correct the blur of the photographed image when the variable power optical system vibrates, and the 32nd group and the third group are corrected.
When the focal lengths of the groups are f32 and f3, respectively, and the focal length at the wide-angle end of the entire system is fW, it is satisfied that 8 <f3 / fW <25 0.3 <| f32 / f3 | <0.75. A variable power optical system with a characteristic anti-vibration function. 2. The third lens unit is arranged in the order from the object side to the 31st lens.
2. The variable power optical system having an image stabilizing function according to claim 1, wherein the first and second lens units are arranged in this order. 3. The third lens unit includes, in order from the object side, a third lens unit having a negative refractive power, a first lens unit having a positive refractive power, and a third lens unit. Claim 1
Variable magnification optical system with anti-vibration function. 4. A first lens unit having a fixed positive refractive power, a second lens unit having a negative refractive power having a variable power function, and a third lens unit having a positive refractive power during zooming and focusing in order from the object side. A variable power optical system having four lens units of a fourth lens unit having a positive refractive power and having both a correction function and a focusing function of correcting an image plane that fluctuates due to zooming; The third group includes two or more lens groups, a 31st group having a negative refractive power and a 32nd group having a positive refractive power.
The two units are moved in the direction perpendicular to the optical axis to correct the blur of the photographed image when the variable magnification optical system vibrates, the focal length at the wide angle end of the entire system is fW, and the focal length at the wide-angle end from the final lens surface to the imaging surface is A variable-magnification optical system having a vibration-proof function characterized by satisfying the following condition: 3 <bfW / fW <6, where bfW is the back focus at the wide-angle end when an optical member having no refractive power is removed. system. 5. When the focal lengths of the 32nd lens unit and the third lens unit are f32 and f3, respectively, 8 <f3 / fW <25 0.3 <| f32 / f3 | <0.75 is satisfied. A variable power optical system having an anti-shake function. 6. 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 third lens unit having a positive refractive power during zooming and focusing in order from the object side. A variable power optical system having four lens units of a fourth lens unit having a positive refractive power and having both a correction function and a focusing function of correcting an image plane that fluctuates due to zooming; The 3rd group is the 31st group with negative refractive power, 1
The 32nd lens having a positive refractive power as a whole having the above negative lens
Group, and a third group including one positive lens,
A variable power optical system having an image stabilizing function, wherein the second unit is moved in a direction perpendicular to the optical axis to correct blurring of a captured image when the variable power optical system vibrates. 7. When the focal lengths of the second and third lens units are f32 and f3, respectively, and the focal length at the wide-angle end of the entire system is fW, 8 <f3 / fW <25 0.3 <| f32 / f3 | <0.75, wherein the variable-power optical system having a vibration-proof function according to claim 6, wherein | <0.75 is satisfied. 8. When the focal length of the second lens unit is f2, and the focal lengths at the wide-angle end and the telephoto end of the entire system are fW and fT, respectively: A variable power optical system having an image stabilizing function according to any one of claims 1 to 7, which satisfies the following condition: