JP2000298235A - Zoom lens and video camera using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a zoom lens capable of correcting a hand shake and of being made small in size and light in weight. SOLUTION: A 1st lens group which has positive refracting power and is fixed about an image plane, a 2nd lens group which has negative refracting power and varies power by moving along the optical axis, a 3rd lens group which has positive refracting power and is fixed about the image plane, a 4-th lens group which has negative refracting power and is fixed about the image plane, and a 5-th lens group which has positive refracting power and moves along the optical axis so as to hold the image plane varying owing to the movement of the 2nd lens group and an object at a fixed position from a reference surface are arranged in order from the object side to the image plane side. When a hand shake is made, the 3rd lens group, which has the positive refracting power, is shifted at right angles to the optical axis to correct the movement of an image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens and a video camera using the same. More specifically,
The present invention relates to a zoom lens having a camera shake correction function for optically correcting image shake caused by camera shake, vibration, and the like, and a video camera using the same.

[0002]

2. Description of the Related Art Conventionally, a photographing system such as a video camera has been required to have a shake preventing function for preventing vibration such as camera shake, and various types of anti-shake optical systems have been proposed. For example, in Japanese Patent Application Laid-Open No. 8-29737, a two-lens optical system for camera shake correction is mounted on the front surface of a zoom lens, and one of the two optical systems is moved perpendicularly to the optical axis. A device for correcting the movement of an image due to camera shake is disclosed.

Also, Japanese Patent Application Laid-Open No. 7-128619 discloses that a part of a third lens group composed of a plurality of lenses of a four-group zoom lens is moved perpendicularly to the optical axis. Discloses a technique for correcting the movement of an image due to camera shake.

[0004]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open No. Hei 8-2
In the device described in Japanese Patent No. 9737, since the optical system for camera shake correction is mounted on the front surface of the zoom lens, the lens diameter of the optical system for camera shake correction becomes large, and accordingly the entire device becomes large. As a result, the load on the drive system is increased, which is disadvantageous for miniaturization, weight reduction, and power saving.

[0005] Japanese Patent Application Laid-Open No. 7-128619 discloses a technique in which a part of a third lens group fixed to an image plane is moved perpendicularly to an optical axis, thereby forming an image due to camera shake. Because the camera shake is corrected, it is advantageous in terms of miniaturization and weight reduction as compared with the type in which the optical system for camera shake correction is mounted on the front of the zoom lens, but includes a joint in the lens group for camera shake correction Therefore, sufficient aberration correction could not be performed at the time of camera shake correction. Further, when a fixed lens group having a negative refractive power is arranged in front of the lens group for camera shake correction, a wide light beam enters the lens group for camera shake correction, so that the effective diameter is small. There is a problem that it becomes large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and is a five-group zoom lens, in which a third lens group fixed to an image plane during zooming and focusing. It is an object of the present invention to provide a zoom lens which can correct camera shake by moving the lens in a direction perpendicular to the optical axis, and which can be reduced in size and weight, and a video camera using the same.

[0007]

In order to achieve the above-mentioned object, a zoom lens according to the present invention has a positive refractive power, which is arranged in order from an object side to an image plane side, and has an image plane. And a second lens group having a negative refractive power and performing a zooming action by moving on the optical axis.
A lens group, a third lens group having a positive refractive power and fixed to the image plane, a fourth lens group having a negative refractive power and fixed to the image plane, and a positive Having a refractive power, the second
A zoom lens comprising: a lens group and a fifth lens group that moves on the optical axis such that an image plane that fluctuates due to movement of the object is kept at a fixed position from the reference plane. By moving the image in a direction perpendicular to the optical axis, the image shake at the time of camera shake is corrected.
According to the configuration of the zoom lens, the size can be reduced as compared with a type in which an optical system for camera shake correction is mounted on the front surface of the zoom lens. In addition, since the entire group of optical performances is decentered, deterioration of aberration can be suppressed as compared with a type in which a part of the lens inside the group is moved. Further, since a lens group having a negative refractive power is used as the fourth lens group, a long back focus can be easily secured, and a long back focus is required as in an optical system for 3CCD. This is suitable for an optical system.

In the zoom lens according to the present invention, it is preferable that the fourth lens group includes two lenses. In this case, it is preferable that the fourth lens group includes two lenses, that is, a cemented lens of a lens having a negative refractive power and a lens having a positive refractive power arranged in order from the object side. In this case, the fourth lens group is composed of two lenses, a lens having a positive refractive power and a lens having a negative refractive power, which are arranged in order from the object side and are separated from each other. preferable. In this case, the fourth lens group is composed of two lenses, a lens having a negative refractive power and a lens having a positive refractive power, which are arranged in order from the object side and are separated from each other. preferable.

In the above-described zoom lens according to the present invention, the third lens group is arranged in order from the object side.
And a lens having a negative refractive power separated from each other;
It is preferable to include three lenses, a lens having a positive refractive power and a lens having a positive refractive power, and include at least one aspheric surface. According to this preferred example, since the third lens group is composed of three single lenses including at least one aspheric surface and does not include a cemented lens, the degree of freedom in design is increased, and good aberrations are obtained even when camera shake is corrected. Performance can be ensured.

In the zoom lens according to the present invention, the third lens group is arranged in order from the object side.
And a lens having a positive refractive power separated from each other;
It is preferable that the lens includes three lenses, a lens having a negative refractive power and a lens having a positive refractive power, and includes at least one aspheric surface.

In the above-described zoom lens according to the present invention, the third lens group is disposed in order from the object side.
And a lens having a positive refractive power separated from each other;
It is preferable to include three lenses, a lens having a positive refractive power and a lens having a negative refractive power, and include at least one aspheric surface.

In the above-described zoom lens according to the present invention, the third lens group is arranged in order from the object side.
Further, it is preferable to include two lenses, a lens having a positive refractive power and a lens having a negative refractive power and having the same sag amount on the object-side surface and the image-side surface, which are separated from each other. According to this preferred example, it is not necessary to determine the front and back of the lens at the time of assembling, so that the cost in the process can be reduced. In this case, the third lens group is
It is preferable to include at least one aspheric surface.

In the zoom lens according to the present invention, it is preferable that the third lens group includes a single lens having a positive refractive power. According to this preferred example, the burden on the drive system at the time of camera shake correction is reduced,
Power consumption can be reduced. In this case, it is preferable that the third lens group includes at least one aspheric surface.

In the zoom lens according to the present invention, the third lens group is arranged in order from the object side.
And a lens having a negative refractive power separated from each other;
It preferably comprises two lenses, a lens having a positive refractive power. According to this preferred example, by making the lens on the image plane side convex, the height of light rays emitted from the third lens group is reduced, so that the lens diameter of the fourth lens group can be reduced. In this case, it is preferable that the third lens group includes at least one aspheric surface.

In the zoom lens according to the present invention, in the configuration in which the third lens group includes at least one aspherical surface, the third lens unit has an aspherical surface having a diameter equal to 10% of the lens effective diameter. The local radius of curvature is r ₃₁ , and the local radius of curvature at 90% of the lens effective diameter is r ₃₉
In this case, it is preferable to satisfy the following conditional expression (1).

0.01 <r ₃₁ / r ₃₉ <2.00 (1) According to this preferred example, sufficient aberration performance for realizing high resolution can be obtained.

In the configuration of the zoom lens according to the present invention, when the focal length of the third lens unit is f ₃ and the combined focal length of the third and fourth lens units is f ₃₄ , the following conditional expression is satisfied. It is preferable to satisfy (2).

0.40 <| f ₃ / f ₃₄ | <0.85 (2) According to this preferable example, it is possible to suppress the deterioration of the aberration performance and to loosen the assembly tolerance at the time of manufacturing. can do. In addition, since the amount of movement of the lens at the time of camera shake correction is small, the lens diameter can be reduced, and the size can be reduced.

In the configuration of the zoom lens according to the present invention, when the focal length of the entire system at the wide-angle end is fw and the distance from the last lens surface to the image forming surface in air is BF, the following conditional expression ( It is preferable to satisfy 3).

2.0 <BF / fW <5.0 (3) According to this preferred example, it is possible to insert a color separation optical system having a length capable of performing sufficient color separation. it can. Further, since the back focus does not become unnecessarily long, a small zoom lens can be realized.

In the configuration of the zoom lens according to the present invention, the focal length of the entire system at the wide-angle end is fw, and the i-th focal length.
The focal length of the lens unit fi (i = 1 to 5), when the third lens group the combined focal length of the fourth lens group and a f _34, to satisfy the following conditional expression (4) to (7) preferable.

5.0 <f1 / fW <8.0 (4) 0.5 <| f2 | / fW <1.6 (5) 4.0 <f34 / fW <9.5 (6) 2.0 <f5 / fW <5.0 (7) According to this preferred example, it is easy to correct the aberration and the size can be reduced.

In the zoom lens system according to the present invention, the amount of movement of the third lens group at the focal length f of the entire system at the time of camera shake correction is Y, and the amount of movement of the third lens group at the telephoto end is Yt. When the focal length at the telephoto end is ft, it is preferable to satisfy the following conditional expressions (8) and (9).

Yt> Y (8) (Y / Yt) / (f / ft) <1.5 (9) According to this preferred example, deterioration of optical performance can be suppressed.

[0025] The video camera according to the present invention is a video camera provided with a zoom lens, wherein the zoom lens according to the present invention is used as the zoom lens. According to the configuration of the video camera, a video camera having a small and high-performance camera shake correction function can be realized.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically with reference to embodiments.

FIG. 1 is a layout diagram showing a basic configuration of a zoom lens having a camera shake correction function according to an embodiment of the present invention.

As shown in FIG. 1, the zoom lens according to the present embodiment has positive refraction arranged in order from the object side (left side in FIG. 1) to the image plane side (right side in FIG. 1). A first lens group having a force and fixed to an image plane;
A second lens group having a negative refractive power and performing a zooming action by moving on the optical axis, a third lens group having a positive refractive power and fixed with respect to the image plane, Has a refractive power of
A fourth lens group fixed with respect to the image plane, and having a positive refracting power, and an image plane which fluctuates due to the movement of the second lens group and the object is kept on the optical axis so as to maintain a constant position from the reference plane. And a fifth lens group that moves the lens. Then, when camera shake occurs, the image shake is corrected by shifting the third lens group having a positive refractive power in a direction perpendicular to the optical axis.

Hereinafter, the present invention will be described in more detail with reference to further specific embodiments.

<First Embodiment> FIG. 2 shows a first embodiment of the present invention.
FIG. 3 is a layout diagram showing a configuration of a zoom lens according to the embodiment.

As shown in FIG. 2, a first lens group 21, a second lens group 22, and a third lens group 23 are arranged from the object side (left side in FIG. 2) to the image plane side (right side in FIG. 2). , Fourth
A lens group 24 and a fifth lens group 25 are arranged in this order, thereby forming a zoom lens.

The first lens group 21 has a positive refractive power,
At the time of zooming and focusing, it is fixed with respect to the image plane. The second lens group 22 has a negative refractive power and performs a zooming action by moving on the optical axis. The third lens group 23 includes three lenses of a negative lens, a positive lens, and a positive lens arranged in order from the object side, includes at least one aspheric surface, and has a positive refractive power as a whole. Have. The fourth lens group 24 is composed of two lenses, a cemented lens of a negative lens and a positive lens arranged in order from the object side, has a negative refractive power as a whole, and at the time of zooming and focusing. It is fixed with respect to the image plane. The fifth lens group 25 has a positive refractive power, and moves on the optical axis to simultaneously move the image by zooming and adjust the focus. When camera shake occurs, image shake is corrected by moving the third lens group 23 in a direction perpendicular to the optical axis.

As described above, by introducing at least one aspheric surface into any of the lenses of the third lens group 23, the performance when the lens is shifted can be improved.

In the aspheric surface of the third lens unit 23, the local radius of curvature at 10% of the effective lens diameter is r ₃₁ ,
Let r be the local radius of curvature at 90% of the effective lens diameter
_{When 39} is satisfied, it is desirable that the following conditional expression (1) is satisfied.

0.01 <r ₃₁ / r ₃₉ <2.00 (1) The conditional expression (1) is an expression relating to the amount of aspherical surface, and is sufficient for realizing a high resolution of the zoom lens. This defines the conditions for obtaining the aberration performance. When r ₃₁ / r ₃₉ is 2.00 or more, the correction amount of the spherical aberration becomes too small, and the coma flare easily occurs when the lens moves. On the other hand, when r ₃₁ / r ₃₉ is 0.01 or less, the correction amount of the spherical aberration becomes too large, and sufficient aberration performance cannot be obtained.

Note that the local radius of curvature C here is
This is a value obtained by algebraically calculating based on the aspherical coefficient calculated from the sag amount of the surface shape, and can be obtained by the following equations (a) and (b) of (Equation 1).

[0037]

(Equation 1)

The third lens group (correction lens group) 23
It is preferable that the following conditional expression (2) is satisfied, where f _{3 is} the focal length of the lens and f ₃₄ is the combined focal length of the third lens unit and the fourth lens unit.

0.40 <| f ₃ / f ₃₄ | <0.85 (2) The conditional expression (2) is an expression that defines the focal length of the lens for camera shake correction. When | f ₃ / f ₃₄ | is 0.40 or less, the power of the correcting lens becomes too strong, the aberration performance is greatly deteriorated, and the assembly tolerance at the time of manufacturing becomes severe. On the other hand, when | f ₃ / f ₃₄ | is 0.85 or more, the amount of movement of the lens at the time of camera shake correction becomes large, so that the lens diameter becomes large, which is disadvantageous for downsizing.

The focal length of the entire system at the wide-angle end is represented by f
w, when the distance from the last lens surface to the image forming surface in the air is BF, it is desirable that the following conditional expression (3) is satisfied.

2.0 <BF / fW <5.0 (3) The conditional expression (3) is an expression for realizing a zoom lens having a long back focus like three plates. BF / f
When W is 2.0 or less, a color separation optical system having a length that allows sufficient color separation cannot be inserted. When the BF / fW is 5.0 or more, the back focus becomes unnecessarily long, and a small zoom lens cannot be realized.

The focal length of the entire system at the wide-angle end is represented by f
w, the focal length of the ith lens group is fi (i = 1 to 5), and the combined focal length of the third lens group 23 and the fourth lens group 24 is f
_{When 34} is satisfied, it is desirable that the following conditional expressions (4) to (7) are satisfied.

5.0 <f1 / fW <8.0 (4) 0.5 <| f2 | / fW <1.6 (5) 4.0 <f34 / fW <9.5 (6) 2.0 <f5 / fW <5.0 (7) The conditional expression (4) is an expression relating to the refractive power of the first lens group 21. If f1 / fW is 5.0 or less, the refractive power of the first lens group 21 becomes too large, so that it becomes difficult to correct spherical aberration on the long focal length side. If f1 / fW is 8.0 or more, the lens length increases, and a small zoom lens cannot be realized.

The conditional expression (5) is an expression relating to the refractive power of the second lens group 22. If | f2 | / fW is 0.5 or less, the size can be reduced, but the Petzval sum of the entire system becomes negative and the field curvature cannot be corrected. When | f2 | / fW is 1.6 or more, it becomes easy to correct aberrations, but the variable power system becomes longer, and the size of the entire system cannot be reduced.

The conditional expression (6) is an expression relating to the refractive power of the third lens group 23. If f34 / fW is equal to or less than 4.0, the refractive power of the third lens group 23 becomes too large, and it becomes difficult to correct spherical aberration. When f34 / fW becomes 9.5 or more, the combined system of the first lens group 21 to the third lens group 23 becomes a divergent system, so the lens outer diameter of the fourth lens group 24 located behind the lens system is reduced. And the Petzval sum of the whole system cannot be reduced.

The above conditional expression (7) is an expression relating to the refractive power of the fourth lens group 24. When f5 / fW is 2.0 or less, the comprehensive range of the screen becomes narrow, and it is necessary to increase the lens diameter of the first lens group 21 in order to obtain a desired range. Therefore, reduction in size and weight cannot be achieved. . When f5 / fW is 5.0 or more, the aberration can be easily corrected, but the amount of movement of the fourth lens group 24 at the time of short-distance shooting increases, and not only the entire system cannot be reduced in size but also. ,
It becomes difficult to correct the imbalance of off-axis aberrations at the time of short-range shooting and the long-range shooting.

The amount of movement of the third lens group 23 at the focal length f of the entire system at the time of camera shake correction is Y, the amount of movement of the third lens group 23 at the telephoto end is Yt, and the focal length at the telephoto end is ft. At this time, it is desirable to satisfy the following conditional expressions (8) and (9).

Yt> Y (8) (Y / Yt) / (f / ft) <1.5 (9) The above conditional expressions (8) and (9) satisfy the third lens group 23. Is an expression relating to the amount of movement of. In the case of a zoom lens, when the correction angle is constant in the entire zoom range, the larger the zoom ratio, the higher the third
The larger the amount of movement of the lens group 23, and conversely, the smaller the zoom ratio, the smaller the amount of movement of the third lens group 23. Yt is Y
When (Y / Yt) / (f / ft) becomes 1.5 or more, the correction becomes excessive and the optical performance is greatly deteriorated.

<Second Embodiment> FIG. 6 shows a second embodiment of the present invention.
FIG. 3 is a layout diagram showing a configuration of a zoom lens according to the embodiment.

As shown in FIG. 6, from the object side (left side in FIG. 6) to the image plane side (right side in FIG. 6), a first lens group 61, a second lens group 62, and a third lens group 63 are arranged. , Fourth
The lens group 64 and the fifth lens group 65 are arranged in this order, thereby forming a zoom lens.

The first lens group 61 has a positive refractive power,
At the time of zooming and focusing, it is fixed with respect to the image plane. The second lens group 62 has a negative refractive power, and performs a zooming action by moving on the optical axis. The third lens group 63 includes three lenses, a negative lens, a positive lens, and a positive lens, arranged in order from the object side, includes at least one aspheric surface, and has a positive refractive power as a whole. have. The fourth lens group 64 is composed of two lenses, a cemented lens of a negative lens and a positive lens, arranged in order from the object side, has a negative refractive power as a whole, and at the time of zooming and focusing. It is fixed with respect to the image plane. The fifth lens group 65 has a positive refractive power, and moves on the optical axis to simultaneously move the image by zooming and adjust the focus. When camera shake occurs, image shake is corrected by moving the third lens group 63 in a direction perpendicular to the optical axis.

As described above, by introducing at least one aspheric surface into any of the lenses of the third lens group 63, the performance when the lens is shifted can be improved.

Also in the zoom lens of the present embodiment,
Similarly to the first embodiment, the conditional expressions (1) to (1)
It is desirable to satisfy (9).

<Third Embodiment> FIG. 10 is a layout diagram showing a configuration of a zoom lens according to a third embodiment of the present invention.

As shown in FIG. 10, from the object side (left side in FIG. 10) to the image plane side (right side in FIG. 10), a first lens group 101, a second lens group 102, and a third lens group 103 are arranged. , A fourth lens group 104, and a fifth lens group 105 are arranged in this order, thereby constituting a zoom lens.

The first lens group 101 has a positive refractive power and is fixed with respect to the image plane during zooming and during focusing. The second lens group 102 has a negative refractive power, and performs a zooming action by moving on the optical axis. The third lens group 103 includes three lenses, a positive lens, a positive lens, and a negative lens, arranged in order from the object side, includes at least one aspheric surface, and has a positive refractive power as a whole. Have. The fourth lens group 104 is composed of two lenses, a cemented lens of a negative lens and a positive lens, which are arranged in order from the object side, has a negative refractive power as a whole, and , In a state fixed to the image plane. The fifth lens group 105 has a positive refractive power, and moves on the optical axis to simultaneously move the image by zooming and adjust the focus. When camera shake occurs, image shake is corrected by moving the third lens group 103 in a direction perpendicular to the optical axis.

As described above, by introducing at least one aspherical surface into any of the lenses of the third lens group 63, the performance when the lens is shifted can be improved.

Also in the zoom lens of the present embodiment,
Similarly to the first embodiment, the conditional expressions (1) to (1)
It is desirable to satisfy (9).

<Fourth Embodiment> FIG. 14 is a layout diagram showing a configuration of a zoom lens according to a fourth embodiment of the present invention.

As shown in FIG. 14, the first lens group 141, the second lens group 142, and the third lens group 143 are arranged from the object side (left side in FIG. 14) to the image plane side (right side in FIG. 14). , A fourth lens group 144, and a fifth lens group 145 are arranged in this order, thereby constituting a zoom lens.

The first lens group 141 has a positive refractive power and is fixed with respect to the image plane during zooming and focusing. The second lens group 142 has a negative refractive power, and performs a zooming action by moving on the optical axis. The third lens group 143 includes a negative lens and a positive lens, which are arranged in order from the object side and have surfaces with the same sag amount.
It consists of two lenses and has a positive refractive power as a whole. The fourth lens group 144 includes two lenses, a cemented lens of a positive lens and a negative lens arranged in order from the object side, has a negative refractive power as a whole, Is in a state fixed to the image plane. The fifth lens group 145 has a positive refractive power, and moves on the optical axis to simultaneously move the image by zooming and adjust the focus. When camera shake occurs, by moving the third lens group 143 in a direction perpendicular to the optical axis,
Image shake is corrected.

As described above, by combining the third lens group 143 having a positive refractive power as a whole and the fourth lens group 144 having a negative refractive power as a whole, the light beam incident on the fifth lens group 145 is obtained. Can be lowered. That is, since the lens diameter of the fourth lens group 144 can be reduced, the load on the focus actuator can be reduced.

By introducing at least one aspherical surface into any of the lenses of the third lens group 143,
The performance when the lens is shifted can be improved.

In the zoom lens according to the present embodiment,
Similarly to the first embodiment, the conditional expressions (1) to (1)
It is desirable to satisfy (9).

<Fifth Embodiment> FIG. 18 is a layout diagram showing a configuration of a zoom lens according to a fifth embodiment of the present invention.

As shown in FIG. 18, from the object side (left side in FIG. 18) to the image plane side (right side in FIG. 18), a first lens group 181, a second lens group 182, and a third lens group 183 are arranged. , A fourth lens group 184, and a fifth lens group 185 are arranged to constitute a zoom lens.

The first lens group 181 has a positive refractive power, and is fixed with respect to the image plane during zooming and focusing. The second lens group 182 has a negative refracting power and performs a zooming action by moving on the optical axis. The third lens group 183 includes one lens having a positive refractive power. The fourth lens group 184 includes two lenses, a cemented lens of a negative lens and a positive lens arranged in order from the object side, has a negative refractive power as a whole, Is in a state fixed to the image plane. The fifth lens group 185 has a positive refractive power, and moves on the optical axis to simultaneously move the image by zooming and adjust the focus. When camera shake occurs, the third
By moving the lens group 183 in a direction perpendicular to the optical axis, image shake is corrected.

As described above, by forming the shift lens group (third lens group 183) with one lens, the tolerance can be reduced.

By introducing at least one aspherical surface into any of the lenses of the third lens group 183,
The performance when the lens is shifted can be improved.

Also in the zoom lens of the present embodiment,
Similarly to the first embodiment, the conditional expressions (1) to (1)
It is desirable to satisfy (9).

<Sixth Embodiment> FIG. 22 is a layout diagram showing a configuration of a zoom lens according to a sixth embodiment of the present invention.

As shown in FIG. 22, the first lens group 221, the second lens group 222, and the third lens group 223 are arranged from the object side (left side in FIG. 22) to the image plane side (right side in FIG. 22). , A fourth lens group 224 and a fifth lens group 225 are arranged, thereby constituting a zoom lens.

The first lens group 221 has a positive refractive power, and is fixed with respect to the image plane during zooming and focusing. The second lens group 222 has a negative refractive power, and performs a zooming action by moving on the optical axis. The third lens group 223 includes two lenses, a negative lens and a positive lens, arranged in order from the object side, and has a positive refractive power as a whole. The fourth lens group 224 is composed of two lenses, a positive lens and a negative lens, arranged in order from the object side, has a negative refractive power as a whole, and has an image surface at the time of zooming and focusing. In a fixed state with respect to. The fifth lens group 225 has a positive refractive power, and moves on the optical axis to simultaneously move the image by zooming and adjust the focus. When camera shake occurs, the third
By moving the lens group 223 in a direction perpendicular to the optical axis, image blur is corrected.

By introducing at least one aspheric surface into any of the lenses of the third lens group 223,
The performance when the lens is shifted can be improved.

In the zoom lens according to the present embodiment,
Similarly to the first embodiment, the conditional expressions (1) to (1)
It is desirable to satisfy (9).

<Seventh Embodiment> FIG. 26 is a layout diagram showing a configuration of a zoom lens according to a seventh embodiment of the present invention.

As shown in FIG. 26, from the object side (left side in FIG. 26) to the image plane side (right side in FIG. 26), a first lens group 261, a second lens group 262, and a third lens group 263 are arranged. , A fourth lens group 264 and a fifth lens group 265 are arranged, thereby constituting a zoom lens.

The first lens group 261 has a positive refractive power, and is fixed with respect to the image plane during zooming and focusing. The second lens group 262 has a negative refracting power and performs a zooming action by moving on the optical axis. The third lens group 263 includes two lenses, a negative lens and a positive lens, arranged in order from the object side, and has a positive refractive power as a whole. The fourth lens group 264 includes two lenses, a negative lens and a positive lens, arranged in order from the object side. The fourth lens group 264 has a negative refractive power as a whole. In a fixed state with respect to. The fifth lens group 265 has a positive refractive power, and moves on the optical axis to simultaneously move an image by zooming and adjust focus. When camera shake occurs, the third
By moving the lens group 263 in a direction perpendicular to the optical axis, image shake is corrected.

By introducing at least one aspherical surface into any of the lenses of the third lens group 263,
The performance when the lens is shifted can be improved.

In the zoom lens according to the present embodiment,
Similarly to the first embodiment, the conditional expressions (1) to (1)
It is desirable to satisfy (9).

[0081]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to specific examples.

(Example 1) The following Table 1 shows specific examples of the zoom lens according to the first embodiment.

[0083]

[Table 1]

In the above (Table 1), r (mm) is the radius of curvature of the lens surface, d (mm) is the thickness of the lens or the air gap between the lenses, n is the refractive index of each lens with respect to the d line, ν
Indicates the Abbe number of each lens with respect to the d-line (the same applies to Examples 1 to 7 below).

Table 2 below shows the aspherical coefficients of the zoom lens of this embodiment.

[0086]

[Table 2]

The following Table 3 shows the air gap (mm) that can be varied by zooming when the object point is at a position 2 m from the front end of the lens. The standard position in the following (Table 3) is a position where the magnification of the second lens group 22 is -1. In the following (Table 3), f (mm), F / No, ω
(゜) indicates the focal length at the wide-angle end, the standard position, the telephoto end, the F-number,
The half angle of view.

[0088]

[Table 3]

The third lens group 2 of the zoom lens according to the present embodiment
In the aspheric surface of No. 3, when the local radius of curvature at 10% of the effective lens diameter is r ₃₁ and the local radius of curvature at 90% of the effective lens diameter is r ₃₉ , r ₃₁ / r ₃₉ Is 0.64. That is, the conditional expression (1) is satisfied, and sufficient aberration performance for achieving high resolution is obtained.

In the zoom lens of this embodiment,
The focal length of the third lens group (correction lens group) 23 is f ₃ ,
When the third lens group 23 the composite focal length of the fourth lens group 24 and a _{f 34, | f 3 / f} 34 | value is 0.59. That is, since the conditional expression (2) is satisfied, it is possible to suppress the deterioration of the aberration performance, and it is possible to loosen the assembly tolerance at the time of manufacturing. Also,
Since the amount of movement of the lens at the time of camera shake correction is small, the lens diameter can be reduced and the size can be reduced.

In the zoom lens of this embodiment,
When the focal length of the entire system at the wide-angle end is fw, and the distance from the last lens surface to the imaging surface in air is BF,
The value of BF / fW is 4.09. That is, it is possible to insert a color separation optical system that satisfies the conditional expression (3) and has a length that allows sufficient color separation. Further, since the back focus does not become unnecessarily long, a small zoom lens can be realized.

In the zoom lens of this embodiment,
The focal length of the entire system at the wide angle end fw, the focal length of the i-th lens unit fi (i = 1~5), when the third lens group 23 the composite focal length of the fourth lens group 24 and a f _34, f1
The values of / fW, | f2 | / fW, f34 / fW, and f5 / fW are 7.00, 1.25, 9.14, and 3.7, respectively.
9 That is, since the conditional expressions (4) to (7) are satisfied, the aberration can be easily corrected and the size can be reduced.

FIGS. 3 to 5 show aberration diagrams at the wide-angle end, the standard position, and the telephoto end of the zoom lens according to the present embodiment. In each figure, (a) is a diagram of spherical aberration,
The solid line indicates the value for the d line, and the dashed line indicates the sine condition.
(B) is a diagram of astigmatism, where a solid line indicates sagittal field curvature and a broken line indicates meridional field curvature.
(C) is a diagram showing distortion. (D) is a diagram of the axial chromatic aberration, where the solid line shows the value for the d line, the short dashed line shows the value for the F line, and the long dashed line shows the value for the C line. (E) is a diagram of lateral chromatic aberration, where a short broken line indicates a value with respect to the F line, and a long broken line indicates a value with respect to the C line.

As is clear from the aberration diagrams shown in FIGS. 3 to 5, the zoom lens according to the present embodiment has a sufficient aberration correction capability for realizing high resolution.

(Example 2) The following (Table 4) shows specific examples of the zoom lens according to the second embodiment.

[0096]

[Table 4]

Table 5 below shows the aspherical coefficients of the zoom lens of this embodiment.

[0098]

[Table 5]

The following (Table 6) shows the air gap (mm) that can be changed by zooming when the object point is at a position 2 m from the front end of the lens. The standard position in the following (Table 6) is a position where the magnification of the second lens group 62 is -1. In the following (Table 6), f (mm), F / No, ω
(゜) indicates the focal length at the wide-angle end, the standard position, the telephoto end, the F-number,
The half angle of view.

[0100]

[Table 6]

Third lens group 6 of the zoom lens of this embodiment
In the aspheric surface of No. 3, when the local radius of curvature at 10% of the effective lens diameter is r ₃₁ and the local radius of curvature at 90% of the effective lens diameter is r ₃₉ , r ₃₁ / r ₃₉ Is 0.63. That is, the conditional expression (1) is satisfied.

In the zoom lens of this embodiment,
The focal length of the third lens group (correction lens group) 63 is f ₃ ,
When the third lens group 63 the combined focal length of the fourth lens group 64 and a _{f 34, | f 3 / f} 34 | value is 0.59. That is, the conditional expression (2) is satisfied.

In the zoom lens of this embodiment,
When the focal length of the entire system at the wide-angle end is fw, and the distance from the last lens surface to the imaging surface in air is BF,
The value of BF / fW is 4.01. That is, the conditional expression (3) is satisfied.

In the zoom lens of this embodiment,
The focal length of the entire system at the wide angle end fw, the focal length of the i-th lens unit fi (i = 1~5), when the third lens group 63 the combined focal length of the fourth lens group 64 and a f _34, f1
The values of / fW, | f2 | / fW, f34 / fW, and f5 / fW are 6.98, 1.25, 9.17, and 3.7, respectively.
0. That is, the conditional expressions (4) to (7) are satisfied.

FIGS. 7 to 9 show aberration diagrams at the wide-angle end, the standard position, and the telephoto end of the zoom lens according to the present embodiment. In each figure, (a) is a diagram of spherical aberration,
The solid line indicates the value for the d line, and the dashed line indicates the sine condition.
(B) is a diagram of astigmatism, where a solid line indicates sagittal field curvature and a broken line indicates meridional field curvature.
(C) is a diagram showing distortion. (D) is a diagram of the axial chromatic aberration, where the solid line shows the value for the d line, the short dashed line shows the value for the F line, and the long dashed line shows the value for the C line. (E) is a diagram of lateral chromatic aberration, where a short broken line indicates a value with respect to the F line, and a long broken line indicates a value with respect to the C line.

As is clear from the aberration diagrams shown in FIGS. 7 to 9, the zoom lens according to the present embodiment has a sufficient aberration correcting ability to realize high resolution.

Example 3 The following (Table 7) shows specific examples of the zoom lens according to the third embodiment.

[0108]

[Table 7]

The following (Table 8) shows the aspherical coefficients of the zoom lens of this embodiment.

[0110]

[Table 8]

The following (Table 9) shows the air gap (mm) that can be varied by zooming when the object point is at a position 2 m from the tip of the lens. The standard position in the following (Table 9) is a position where the magnification of the second lens group 102 is -1. In the following (Table 9), f (mm), F / No, ω
(゜) indicates the focal length at the wide-angle end, the standard position, the telephoto end, the F-number,
The half angle of view.

[0112]

[Table 9]

Third lens group 1 of the zoom lens according to the present embodiment
In the aspheric surface of No. 03, when the local radius of curvature at 10% of the lens effective diameter is r ₃₁ and the local radius of curvature at 90% of the lens effective diameter is r ₃₉ , r ₃₁ / r ₃₉
Is 0.86. That is, the conditional expression (1) is satisfied.

In the zoom lens of this embodiment,
When the focal length of the third lens group (correction lens group) 103 is f ₃ and the combined focal length of the third lens group 103 and the fourth lens group 104 is f ₃₄ , the value of | f ₃ / f ₃₄ | is 0. .
62. That is, the conditional expression (2) is satisfied.

In the zoom lens of this embodiment,
When the focal length of the entire system at the wide-angle end is fw, and the distance from the last lens surface to the imaging surface in air is BF,
The value of BF / fW is 3.58. That is, the conditional expression (3) is satisfied.

In the zoom lens of this embodiment,
The focal length of the entire system at the wide angle end fw, the focal length of the i-th lens unit fi (i = 1~5), when the third lens group 103 to the composite focal length of the fourth lens group 104 and the f _34,
f1 / fW, | f2 | / fW, f34 / fW, f5 / f
The values of W are 6.99, 1.25, 8.82,
3.23. That is, the above conditional expressions (4) to (7)
Is satisfied.

FIGS. 11 to 13 show aberration diagrams at the wide-angle end, the standard position, and the telephoto end of the zoom lens according to the present embodiment. In each figure, (a) is a diagram of the spherical aberration, the solid line shows the value for the d-line, and the broken line shows the sine condition. (B) is a diagram of astigmatism, where a solid line indicates sagittal field curvature and a broken line indicates meridional field curvature.
(C) is a diagram showing distortion. (D) is a diagram of the axial chromatic aberration, where the solid line shows the value for the d line, the short dashed line shows the value for the F line, and the long dashed line shows the value for the C line. (E) is a diagram of lateral chromatic aberration, where a short broken line indicates a value with respect to the F line, and a long broken line indicates a value with respect to the C line.

As is apparent from the aberration diagrams shown in FIGS. 11 to 13, the zoom lens according to the present embodiment has a sufficient aberration correction capability for realizing high resolution.

(Example 4) The following (Table 10)
Specific examples of the zoom lens according to the embodiment will be described.

[0120]

[Table 10]

Table 11 below shows the aspherical coefficients of the zoom lens of this embodiment.

[0122]

[Table 11]

The following (Table 12) shows the air gap (mm) that can be changed by zooming when the object point is at a position 2 m from the front end of the lens. The standard position in the following (Table 12) is a position where the magnification of the second lens group 102 is -1. In the following (Table 12), f (mm), F / N
o and ω (゜) are the focal length, F-number, and half angle of view at the wide-angle end, the standard position, and the telephoto end of the zoom lens of (Table 10), respectively.

[0124]

[Table 12]

Third lens group 1 of the zoom lens of the present embodiment
In the aspheric surface of 43, when the local radius of curvature at 10% of the effective lens diameter is r ₃₁ and the local radius of curvature at 90% of the effective lens diameter is r ₃₉ , r ₃₁ / r ₃₉
Are 0.79 and 0.79. That is, the conditional expression (1) is satisfied.

In the zoom lens of this embodiment,
When the focal length of the third lens group (correction lens group) 143 is f ₃ and the combined focal length of the third lens group 143 and the fourth lens group 144 is f ₃₄ , the value of | f ₃ / f ₃₄ | .
62. That is, the conditional expression (2) is satisfied.

In the zoom lens of this embodiment,
When the focal length of the entire system at the wide-angle end is fw, and the distance from the last lens surface to the imaging surface in air is BF,
The value of BF / fW is 3.58. That is, the conditional expression (3) is satisfied.

In the zoom lens of this embodiment,
The focal length of the entire system at the wide angle end fw, the focal length of the i-th lens unit fi (i = 1~5), when the third lens group 143 a composite focal length of the fourth lens group 144 and the f _34,
f1 / fW, | f2 | / fW, f34 / fW, f5 / f
The values of W are 7.00, 1.26, 8.83,
3.23. That is, the above conditional expressions (4) to (7)
Is satisfied.

FIGS. 15 to 17 show aberration diagrams at the wide-angle end, the standard position, and the telephoto end of the zoom lens according to the present embodiment. In each figure, (a) is a diagram of the spherical aberration, the solid line shows the value for the d-line, and the broken line shows the sine condition. (B) is a diagram of astigmatism, where a solid line indicates sagittal field curvature and a broken line indicates meridional field curvature.
(C) is a diagram showing distortion. (D) is a diagram of the axial chromatic aberration, where the solid line shows the value for the d line, the short dashed line shows the value for the F line, and the long dashed line shows the value for the C line. (E) is a diagram of lateral chromatic aberration, where a short broken line indicates a value with respect to the F line, and a long broken line indicates a value with respect to the C line.

As is clear from the aberration diagrams shown in FIGS. 15 to 17, the zoom lens according to the present embodiment has a sufficient aberration correcting ability to realize high resolution.

(Example 5) The following (Table 13)
Specific examples of the zoom lens according to the embodiment will be described.

[0132]

[Table 13]

Table 14 below shows the aspherical coefficients of the zoom lens of this embodiment.

[0134]

[Table 14]

Table 15 below shows the air gap (mm) that can be varied by zooming when the object point is at a position 2 m from the front end of the lens. The standard position in the following (Table 15) is a position where the magnification of the second lens group 182 is -1. In Table 15 below, f (mm), F / N
o and ω (゜) are the focal length, F number, and half angle of incidence at the wide-angle end, the standard position, and the telephoto end of the zoom lens of (Table 13), respectively.

[0136]

[Table 15]

Third lens group 1 of the zoom lens according to this embodiment
In the aspheric surface of 83, when the local radius of curvature at 10% of the effective lens diameter is r ₃₁ and the local radius of curvature at 90% of the effective lens diameter is r ₃₉ , r ₃₁ / r ₃₉
Are 1.02 (the eleventh surface) and 0.26 (the twelfth surface). That is, the conditional expression (1) is satisfied.

In the zoom lens of this embodiment,
When the focal length of the third lens group (correction lens group) 183 is f ₃ and the combined focal length of the third lens group 183 and the fourth lens group 184 is f ₃₄ , the value of | f ₃ / f ₃₄ | .
60. That is, the conditional expression (2) is satisfied.

In the zoom lens of this embodiment,
When the focal length of the entire system at the wide-angle end is fw, and the distance from the last lens surface to the imaging surface in air is BF,
The value of BF / fW is 3.60. That is, the conditional expression (3) is satisfied.

In the zoom lens of this embodiment,
The focal length of the entire system at the wide angle end fw, the focal length of the i-th lens unit fi (i = 1~5), when the third lens group 183 a composite focal length of the fourth lens group 184 and the f _34,
f1 / fW, | f2 | / fW, f34 / fW, f5 / f
The values of W are 6.98, 1.25, 8.93, respectively.
3.36. That is, the above conditional expressions (4) to (7)
Is satisfied.

FIGS. 19 to 21 show aberration diagrams at the wide-angle end, the standard position, and the telephoto end of the zoom lens according to this embodiment. In each figure, (a) is a diagram of the spherical aberration, the solid line shows the value for the d-line, and the broken line shows the sine condition. (B) is a diagram of astigmatism, where a solid line indicates sagittal field curvature and a broken line indicates meridional field curvature.
(C) is a diagram showing distortion. (D) is a diagram of the axial chromatic aberration, where the solid line shows the value for the d line, the short dashed line shows the value for the F line, and the long dashed line shows the value for the C line. (E) is a diagram of lateral chromatic aberration, where a short broken line indicates a value with respect to the F line, and a long broken line indicates a value with respect to the C line.

As is clear from the aberration diagrams shown in FIGS. 19 to 21, the zoom lens according to the present embodiment has a sufficient aberration correcting ability to realize high resolution.

(Example 6) The following (Table 16)
Specific examples of the zoom lens according to the embodiment will be described.

[0144]

[Table 16]

The following (Table 17) shows the aspherical coefficients of the zoom lens of this embodiment.

[0146]

[Table 17]

Table 18 below shows the air gap (mm) that can be varied by zooming when the object point is at a position 2 m from the lens tip. The standard position in the following (Table 18) is a position where the magnification of the second lens group 222 is -1. In the following (Table 18), f (mm), F / N
o and ω (゜) are the focal length, F number, and half angle of incidence at the wide-angle end, the standard position, and the telephoto end of the zoom lens in Table 16 above, respectively.

[0148]

[Table 18]

Third lens group 2 of the zoom lens according to the present embodiment
Assuming that a local radius of curvature at 10% of the lens effective diameter is r ₃₁ and a local radius of curvature at 90% of the lens effective diameter is r _{39 at} 23 aspheric surfaces, r ₃₁ / r ₃₉
Are 1.05 and 0.46. That is, the conditional expression (1) is satisfied.

In the zoom lens of this embodiment,
When the focal length of the third lens group (correction lens group) 223 is f ₃ and the combined focal length of the third lens group 223 and the fourth lens group 224 is f ₃₄ , the value of | f ₃ / f ₃₄ | .
62. That is, the conditional expression (2) is satisfied.

In the zoom lens of this embodiment,
When the focal length of the entire system at the wide-angle end is fw, and the distance from the last lens surface to the imaging surface in air is BF,
The value of BF / fW is 3.58. That is, the conditional expression (3) is satisfied.

In the zoom lens of this embodiment,
The focal length of the entire system at the wide angle end fw, the focal length of the i-th lens unit fi (i = 1~5), when the third lens group 223 a composite focal length of the fourth lens group 224 and the f _34,
f1 / fW, | f2 | / fW, f34 / fW, f5 / f
The values of W are 6.99, 1.25, 8.79, respectively.
3.25. That is, the above conditional expressions (4) to (7)
Is satisfied.

FIGS. 23 to 25 show aberration diagrams at the wide-angle end, the standard position, and the telephoto end of the zoom lens according to the present embodiment. In each figure, (a) is a diagram of the spherical aberration, the solid line shows the value for the d-line, and the broken line shows the sine condition. (B) is a diagram of astigmatism, where a solid line indicates sagittal field curvature and a broken line indicates meridional field curvature.
(C) is a diagram showing distortion. (D) is a diagram of the axial chromatic aberration, where the solid line shows the value for the d line, the short dashed line shows the value for the F line, and the long dashed line shows the value for the C line. (E) is a diagram of lateral chromatic aberration, where a short broken line indicates a value with respect to the F line, and a long broken line indicates a value with respect to the C line.

As is clear from the aberration diagrams shown in FIGS. 23 to 25, the zoom lens of the present embodiment has a sufficient aberration correcting ability to realize high resolution.

(Example 7) The following (Table 19)
Specific examples of the zoom lens according to the embodiment will be described.

[0156]

[Table 19]

Table 20 below shows the aspherical surface coefficients of the zoom lens of this embodiment.

[0158]

[Table 20]

The following (Table 21) shows the air gap (mm) that can be varied by zooming when the object point is at a position 2 m from the lens tip. The standard position in the following (Table 21) is a position where the magnification of the second lens group 262 is -1. In the following (Table 21), f (mm), F / N
o and ω (゜) are the focal length, the F number, and the half angle of incidence at the wide-angle end, the standard position, and the telephoto end of the zoom lens described in (Table 19), respectively.

[0160]

[Table 21]

Third lens group 2 of the zoom lens of this embodiment
When the local radius of curvature at 10% of the effective lens diameter is r ₃₁ and the local radius of curvature at 90% of the effective lens diameter is r ₃₉ in the 63 aspheric surfaces, r ₃₁ / r ₃₉
Are 0.93 and 0.63. That is, the conditional expression (1) is satisfied.

In the zoom lens of this embodiment,
When the focal length of the third lens group (correction lens group) 263 is f ₃ and the combined focal length of the third lens group 263 and the fourth lens group 264 is f ₃₄ , the value of | f ₃ / f ₃₄ | .
61. That is, the conditional expression (2) is satisfied.

In the zoom lens of this embodiment,
When the focal length of the entire system at the wide-angle end is fw, and the distance from the last lens surface to the imaging surface in air is BF,
The value of BF / fW is 3.59. That is, the conditional expression (3) is satisfied.

In the zoom lens of this embodiment,
The focal length of the entire system at the wide angle end fw, the focal length of the i-th lens unit fi (i = 1~5), when the third lens group 263 to the composite focal length of the fourth lens group 264 and the f _34,
f1 / fW, | f2 | / fW, f34 / fW, f5 / f
The values of W are 6.99, 1.25, 8.94, respectively.
3.26. That is, the above conditional expressions (4) to (7)
Is satisfied.

FIGS. 27 to 29 show aberration diagrams at the wide angle end, the standard position, and the telephoto end of the zoom lens according to this embodiment. In each figure, (a) is a diagram of the spherical aberration, the solid line shows the value for the d-line, and the broken line shows the sine condition. (B) is a diagram of astigmatism, where a solid line indicates sagittal field curvature and a broken line indicates meridional field curvature.
(C) is a diagram showing distortion. (D) is a diagram of the axial chromatic aberration, where the solid line shows the value for the d line, the short dashed line shows the value for the F line, and the long dashed line shows the value for the C line. (E) is a diagram of lateral chromatic aberration, where a short broken line indicates a value with respect to the F line, and a long broken line indicates a value with respect to the C line.

As is clear from the aberration diagrams shown in FIGS. 27 to 29, the zoom lens of the present embodiment has a sufficient aberration correcting ability to realize high resolution.

<Eighth Embodiment> FIG. 30 is a layout diagram showing a configuration of a video camera (three-panel video camera) according to an eighth embodiment of the present invention.

As shown in FIG. 30, the video camera according to the present embodiment includes a zoom lens 301, a low-pass filter 302, color separation prisms 303a to 303c, image pickup devices 304a to 304c, a signal processing circuit 305, , A viewfinder 306, a sensor 307 for detecting camera shake, and an actuator 308 for driving a lens. Here, as the zoom lens 301, the zoom lens according to the first embodiment (see FIG. 2) is used, thereby realizing a compact and high-performance video camera with a camera shake correction function.

In this embodiment, the zoom lens shown in FIG. 2 shown in the first embodiment is used. Instead of this zoom lens, the second to seventh embodiments are used. May be used.

In the above embodiment, the camera shake is corrected by shifting the lens group having a positive refractive power. However, the camera shake is corrected by shifting the lens group having a negative refractive power. Do
Similar effects can be obtained.

[0171]

As described above, according to the present invention, according to the present invention, in the five-unit zoom lens, the third lens unit fixed to the image plane at the time of zooming and focusing is perpendicular to the optical axis. By moving the zoom lens in the direction, a camera shake can be corrected, and a zoom lens that can be reduced in size and weight can be realized. Further, by using such a zoom lens, it is possible to realize a compact and high-performance video camera having a camera shake correction function.

[Brief description of the drawings]

FIG. 1 is a layout diagram showing a basic configuration of a zoom lens having a camera shake correction function according to an embodiment of the present invention.

FIG. 2 is a layout diagram showing a configuration of a zoom lens according to the first embodiment of the present invention.

FIG. 3 is an aberration diagram at a wide angle end according to the first embodiment of the present invention.

FIG. 4 is an aberration diagram at a standard position according to the first embodiment of the present invention.

FIG. 5 is an aberration diagram at a telephoto end according to the first embodiment of the present invention.

FIG. 6 is a layout diagram showing a configuration of a zoom lens according to a second embodiment of the present invention.

FIG. 7 is an aberration diagram at a wide-angle end according to a second embodiment of the present invention.

FIG. 8 is an aberration diagram at a standard position according to the second embodiment of the present invention.

FIG. 9 is an aberration diagram at a telephoto end according to a second embodiment of the present invention.

FIG. 10 is a layout diagram showing a configuration of a zoom lens according to a third embodiment of the present invention.

FIG. 11 is an aberration diagram at a wide-angle end according to a third embodiment of the present invention.

FIG. 12 is an aberration diagram at a standard position according to the third embodiment of the present invention.

FIG. 13 is an aberration diagram at a telephoto end according to a third embodiment of the present invention.

FIG. 14 is a layout diagram showing a configuration of a zoom lens according to a fourth embodiment of the present invention.

FIG. 15 is an aberration diagram at a wide-angle end according to a fourth embodiment of the present invention.

FIG. 16 is an aberration diagram at a standard position in Example 4 of the present invention.

FIG. 17 is an aberration diagram at a telephoto end in Example 4 of the present invention.

FIG. 18 is a layout diagram showing a configuration of a zoom lens according to a fifth embodiment of the present invention.

FIG. 19 is an aberration diagram at a wide-angle end according to a fifth embodiment of the present invention.

FIG. 20 is an aberration diagram at a standard position in Example 5 of the present invention.

FIG. 21 is an aberration diagram at a telephoto end in Example 5 of the present invention.

FIG. 22 is a layout diagram illustrating a configuration of a zoom lens according to a sixth embodiment of the present invention.

FIG. 23 is an aberration diagram at a wide angle end according to Embodiment 6 of the present invention.

FIG. 24 is an aberration diagram at a standard position in Example 6 of the present invention.

FIG. 25 is an aberration diagram at a telephoto end in Example 6 of the present invention.

FIG. 26 is a layout diagram showing a configuration of a zoom lens according to a seventh embodiment of the present invention.

FIG. 27 is an aberration diagram at a wide angle end according to a seventh embodiment of the present invention.

FIG. 28 is an aberration diagram at a standard position in Example 7 of the present invention.

FIG. 29 is an aberration diagram at a telephoto end of Example 7 of the present invention.

FIG. 30 is a layout diagram showing a configuration of a video camera according to an eighth embodiment of the present invention.

[Explanation of symbols]

21, 61, 101, 141, 181, 221, 261
First lens group 22, 62, 102, 142, 182, 222, 262
Second lens group 23, 63, 103, 143, 183, 223, 263
Third lens group 24, 64, 104, 144, 184, 224, 264
Fourth lens group 25, 65, 105, 145, 185, 225, 265
Fifth lens group 301 Zoom lens 302 Low-pass filter 303a-c Color separation prism 304a-c Image sensor 305 Signal processing circuit 306 Viewfinder 307 Sensor for detecting camera shake 308 Actuator for driving lens

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 21, 1999 (1999.4.2
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 11

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

In the zoom lens according to the present invention, the third lens group is arranged in order from the object side.
And a lens having a positive refractive power separated from each other;
It preferably comprises two lenses of negative refractive power. According to this preferred example, by making the lens on the object side convex, the height of light rays emitted from the third lens group is reduced, so that the lens diameter of the fourth lens group can be reduced. In this case, it is preferable that the third lens group includes at least one aspheric surface.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0061

[Correction method] Change

[Correction contents]

The first lens group 141 has a positive refractive power and is fixed with respect to the image plane during zooming and focusing. The second lens group 142 has a negative refractive power, and performs a zooming action by moving on the optical axis. The third lens group 143 includes a positive lens and a negative lens which are arranged in order from the object side and have surfaces with the same sag amount.
It consists of two lenses and has a positive refractive power as a whole. The fourth lens group 144 is arranged in order from the object side
It is composed of two lenses, a cemented lens of a negative lens and a positive lens, has a negative refractive power as a whole, and is fixed to the image plane at the time of zooming and focusing. The fifth lens group 145 has a positive refractive power, and moves on the optical axis to simultaneously move the image by zooming and adjust the focus. When camera shake occurs, by moving the third lens group 143 in a direction perpendicular to the optical axis,
Image shake is corrected.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0073

[Correction method] Change

[Correction contents]

The first lens group 221 has a positive refractive power, and is fixed with respect to the image plane during zooming and focusing. The second lens group 222 has a negative refractive power, and performs a zooming action by moving on the optical axis. The third lens group 223 includes a positive lens and a negative lens arranged in order from the object side, and has a positive refractive power as a whole. The fourth lens group 224 is composed of two lenses, a positive lens and a negative lens, arranged in order from the object side, has a negative refractive power as a whole, and has an image surface at the time of zooming and focusing. In a fixed state with respect to. The fifth lens group 225 has a positive refractive power, and moves on the optical axis to simultaneously move the image by zooming and adjust the focus. When camera shake occurs, the third
By moving the lens group 223 in a direction perpendicular to the optical axis, image blur is corrected.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0078

[Correction method] Change

[Correction contents]

The first lens group 261 has a positive refractive power, and is fixed with respect to the image plane during zooming and focusing. The second lens group 262 has a negative refracting power and performs a zooming action by moving on the optical axis. The third lens group 263 is composed of two lenses, a positive lens and a negative lens, arranged in order from the object side, and has a positive refractive power as a whole. The fourth lens group 264 includes two lenses, a negative lens and a positive lens, arranged in order from the object side. The fourth lens group 264 has a negative refractive power as a whole. In a fixed state with respect to. The fifth lens group 265 has a positive refractive power, and moves on the optical axis to simultaneously move an image by zooming and adjust focus. When camera shake occurs, the third
By moving the lens group 263 in a direction perpendicular to the optical axis, image shake is corrected.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H087 KA03 MA15 NA07 PA08 PA09 PA10 PA16 PA20 PB12 PB13 PB14 QA02 QA07 QA17 QA21 QA25 QA34 QA41 QA46 RA05 RA12 RA13 RA41 RA43 SA23 SA27 SA29 SA32 SA63 SA65 SA24 SA24 SB24 SB14 SB14 SB34

Claims (18)

[Claims] 1. A first lens having a positive refractive power and fixed to an image plane, which is arranged in order from an object side to an image plane side.
A lens group, a second lens group having a negative refractive power and performing zooming by moving on the optical axis, and a third lens having a positive refractive power and fixed to the image plane A group, a fourth lens group having a negative refractive power and fixed to an image plane,
And a fifth lens group having a positive refractive power and moving on the optical axis so as to keep the image plane, which fluctuates due to the movement of the object, at a fixed position from the reference plane. A zoom lens, wherein the entire third lens group is moved in a direction perpendicular to an optical axis to correct image shake when camera shake occurs. 2. The zoom lens according to claim 1, wherein the fourth lens group has two lenses. 3. The fourth lens group according to claim 2, wherein the fourth lens group includes two cemented lenses of a lens having a negative refractive power and a lens having a positive refractive power arranged in order from the object side. Zoom lens. 4. The lens system according to claim 2, wherein the fourth lens group includes two lenses, a lens having a positive refractive power and a lens having a negative refractive power, which are arranged in order from the object side and are separated from each other. The zoom lens described. 5. The fourth lens group according to claim 2, wherein the fourth lens group includes two lenses, a lens having a negative refractive power and a lens having a positive refractive power, which are arranged in order from the object side and are separated from each other. The zoom lens described. 6. A third lens group comprising: a lens having a negative refractive power, a lens having a positive refractive power, and a lens having a positive refractive power, which are arranged in order from the object side and are separated from each other. The zoom lens according to claim 1, comprising three lenses and including at least one aspheric surface. 7. A third lens group comprising: a lens having a positive refractive power, a lens having a negative refractive power, and a lens having a positive refractive power, which are arranged in order from the object side and are separated from each other. The zoom lens according to claim 1, comprising three lenses and including at least one aspheric surface. 8. A third lens group comprising: a lens having a positive refractive power, a lens having a positive refractive power, and a lens having a negative refractive power, which are arranged in order from the object side and are separated from each other. The zoom lens according to claim 1, comprising three lenses and including at least one aspheric surface. 9. A lens having a positive refractive power in which a third lens group is arranged in order from the object side and has the same sag amount on the object side surface and the image plane side surface separated from each other; 2. The zoom lens according to claim 1, comprising two lenses having a refractive power. 10. The zoom lens according to claim 1, wherein the third lens group includes one lens having a positive refractive power. 11. The third lens group includes two lenses: a lens having a negative refractive power and a lens having a positive refractive power, which are arranged in order from the object side and are separated from each other. A zoom lens according to claim 1. 12. The zoom lens according to claim 9, wherein the third lens group includes at least one aspheric surface. 13. In the aspheric surface of the third lens group, the local radius of curvature at 10% of the effective lens diameter is r ₃₁ ,
Let r be the local radius of curvature at 90% of the effective lens diameter
Claims 6 to 6 satisfy the following conditional expression (1) when ₃₉ is satisfied:
13. The zoom lens according to any one of items 8 and 12. 0.01 <r ₃₁ / r ₃₉ <2.00 (1) 14. The focal length of the third lens group is f ₃ ,
When the combined focal length of the lens group and the fourth lens group and a f _34, the zoom lens according to any one of claims 1 to 13 to satisfy the following conditional expression (2). 0.40 <| f ₃ / f ₃₄ | <0.85 (2) 15. The focal length of the entire system at the wide-angle end is represented by f
15. The zoom lens according to claim 1, wherein the following conditional expression (3) is satisfied, where BF is the distance from the last lens surface to the image forming surface in the air. 2.0 <BF / fW <5.0 (3) 16. The focal length of the entire system at the wide-angle end is represented by f
w, the focal length of the i-th lens unit fi (i = 1 to 5), when the third lens group the combined focal length of the fourth lens group and a f _34, the following conditional expression (4) to (7) Claim 1 to satisfy
15. The zoom lens according to any one of 15. 5.0 <f1 / fW <8.0 (4) 0.5 <| f2 | / fW <1.6 (5) 4.0 <f34 / fW <9.5 (5) (6) 2.0 <f5 / fW <5.0 (7) 17. When the amount of movement of the third lens group at the focal length f of the entire system at the time of camera shake correction is Y, the amount of movement of the third lens group at the telephoto end is Yt, and the focal length at the telephoto end is ft. 17. The zoom lens according to claim 1, wherein the following conditional expressions (8) and (9) are satisfied. Yt> Y (8) (Y / Yt) / (f / ft) <1.5 (9) 18. A video camera provided with a zoom lens, wherein the zoom lens according to claim 1 is used as the zoom lens.