JP2009175648A - Zoom lens and image pickup apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve the miniaturization, high image quality, and high zoom ratio of a zoom lens. <P>SOLUTION: In the zoom lens configuration having five groups of positive, negative, positive, positive and positive refractive powers, the fifth lens group GR5 is configured of, in order from an object side to an image side, a fixed group GR5-1 having a negative refractive power and being fixed, and a movable group GR5-2 having a positive refractive power and being movable in a direction substantially orthogonal to the optical axis. The image formed on an image surface is movable in a direction substantially orthogonal to the optical axis by moving the movable group of the fifth lens group in the direction substantially orthogonal to the optical axis. The zoom lens is configured to satisfy the following conditional expressions (1) and (2): 0.6<¾f51/f52¾<1.0 (1); and 0.2<fw/f52<0.5 (2), where f51 is the focal length of the fixed group of the fifth lens group, f52 is the focal length of the movable group of the fifth lens group, and fw is the focal length of the entire lens system at a wide-angle end. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a zoom lens and an imaging apparatus. Specifically, the present invention relates to a compact zoom lens and an image pickup apparatus with high image quality and high magnification.

  In recent years, small-sized imaging devices such as consumer video cameras and digital video cameras have been widely used for home use.

  For these small image pickup devices, there is a high demand for downsizing, high image quality, high magnification, etc. with an emphasis on portability, and the shooting lenses mounted on the image pickup device, especially zoom lenses, There is a demand for downsizing and improving lens performance by shortening the depth.

  In recent years, there has been a high demand for optical camera shake correction, and in addition to miniaturization, high image quality, and high magnification, the degree of design difficulty for satisfying the demand for optical camera shake correction has become very high.

  Under such circumstances, the conventional zoom lens includes, for example, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, A fourth lens group having a refractive power and a fifth lens group having a positive refractive power are arranged in order from the object side to the image side, and the third lens group has a lens having a positive refractive power and a negative refractive power. In some cases, the third lens group is movable in a direction substantially orthogonal to the optical axis direction in order to correct image fluctuations during camera shake (see, for example, Patent Document 1).

  In the zoom lens described in Patent Document 1, for example, a zoom lens for a video camera capable of optical camera shake correction is realized by the above-described configuration.

  Further, the conventional zoom lens has, for example, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a positive refractive power. The fourth lens group and the fifth lens group having a positive refractive power are arranged in order from the object side to the image side, and the fifth lens group has a positive subgroup having a positive refractive power and a negative refractive power. Some of them have negative subgroups, and the positive subgroups can be moved in a direction substantially orthogonal to the optical axis direction, thereby shifting the image and enabling camera shake correction.

  In the conventional zoom lenses as described in Patent Document 1 and Patent Document 2 described above, a lens group constituting the zoom lens, particularly on the telephoto side, in order to correct image blur mainly due to camera shake. Is designed so that a part of the image can be moved in a direction substantially perpendicular to the optical axis, and the quality of the image is improved and the optical performance is improved. In addition, the lens configuration is determined so as to satisfy desired optical performance while ensuring miniaturization and high magnification.

  From this point of view, in the zoom lenses described in Patent Document 1 and Patent Document 2, by adopting a five-group lens structure, high image magnification and high image quality are achieved while achieving high image quality. It is possible to secure a correction function and satisfy desired optical performance.

JP 2003-228001 A JP 2006-23593 A

  However, in the conventional zoom lens described above, particularly with the mounting of the optical camera shake correction function, in order to reduce the size of the imaging device including the mechanical mechanism, the increase in the size of the camera shake correction mechanism cannot be ignored. It has the following problems.

  In the zoom lens described in Patent Document 1, the third lens group is movable in a direction substantially orthogonal to the optical axis direction in order to correct image fluctuations during camera shake. Since the diameter of the luminous flux tends to be larger than the other lens groups except for the first lens group, the effective diameter on the lens surface when including camera shake correction becomes very large. This will increase the size of the device.

  Further, since the third lens group exists at substantially the center of the optical axis of the zoom lens and has a strong refractive power, when the third lens group moves in a direction substantially orthogonal to the optical axis direction, the light beam position in the other lens group Fluctuations increase, the effective diameter on the lens surfaces constituting the other lens groups increases, and the imaging apparatus increases in size.

  In the zoom lens described in Patent Document 2, the fifth lens group is configured by a positive subgroup having a positive refractive power and a negative subgroup having a negative refractive power, and the positive subgroup is in the optical axis direction. The image can be shifted to enable camera shake correction by allowing movement in a direction substantially orthogonal to the lens. However, by using a camera shake correction mechanism for the object side lens group (positive subgroup) of the fifth lens group, Space is required for arranging the camera shake correction mechanism on both sides in the optical axis direction of the partial group, and the size of the imaging device is increased accordingly.

  Further, in order to secure the space on both sides in the optical axis direction of the positive subgroup, restrictions on the optical design occur, and there is a possibility that the image quality is deteriorated.

  Further, in the zoom lens described in Patent Document 2, a cemented lens system is configured in the lens configuration on the image side after the second lens group, and in particular, optical performance such as chromatic aberration and resolution on the wide angle side. On the other hand, the aberration is not sufficiently corrected from the viewpoint of optical performance to ensure good high-definition image quality. Accordingly, various aberrations such as axial chromatic aberration and lateral chromatic aberration remain, which adversely affects image quality.

  The above-described problems are particularly serious in realizing a compact and high-power zoom lens because the influence increases as the higher magnification and higher image quality are ensured.

  Therefore, an object of the zoom lens and the imaging apparatus of the present invention is to overcome the above-described problems and to achieve downsizing, high image quality, and high magnification.

In order to solve the above-described problems, the zoom lens has a first lens group having a positive refractive power and a fixed first lens group, and has a negative refractive power and is movable in the optical axis direction in order to at least change the magnification. The second lens group, the third lens group having a positive refractive power and a fixed third lens group, and moving in the optical axis direction in order to correct and focus the focal position by zooming with a positive refractive power The fourth lens group made possible and the fifth lens group having a positive refractive power are arranged in order from the object side to the image side, and the fifth lens group has a negative refractive power and is fixed. And a movable group that has a positive refractive power and is movable in a direction substantially orthogonal to the optical axis. The movable group of the fifth lens group is arranged in order from the object side to the image side. Is moved in a direction substantially perpendicular to the optical axis, so that an image formed on the image plane can be moved in a direction substantially perpendicular to the optical axis. Is a, which is constituted so as to satisfy the following conditional expressions (1) and (2).
(1) 0.6 <| f51 / f52 | <1.0
(2) 0.2 <fw / f52 <0.5
However,
f51: focal length of the fixed group of the fifth lens group f52: focal length of the movable group of the fifth lens group fw: focal length of the entire lens system at the wide angle end.

  Therefore, in the zoom lens, fluctuations in aberrations such as spherical aberration, astigmatism, and distortion are suppressed during camera shake correction.

In order to solve the above-described problem, the imaging apparatus includes a zoom lens and an imaging element that converts an optical image formed by the zoom lens into an electrical signal, and the zoom lens has a positive refractive power. A fixed first lens group, a second lens group having a negative refractive power and movable in the optical axis direction for at least zooming, and a fixed third lens group having a positive refractive power A lens group, a fourth lens group having a positive refractive power and movable in the optical axis direction to correct and focus the focal position by zooming, and a fifth lens group having a positive refractive power Are arranged in order from the object side to the image side, and the fifth lens group has a fixed group having a negative refractive power and a direction having a positive refractive power and substantially perpendicular to the optical axis. A movable group that is movable toward the image side from the object side, and the fifth lens When the movable group of the group is moved in a direction substantially perpendicular to the optical axis, an image formed on the image plane can be moved in a direction substantially perpendicular to the optical axis, and the following conditional expression (1) and condition: This is configured to satisfy the formula (2).
(1) 0.6 <| f51 / f52 | <1.0
(2) 0.2 <fw / f52 <0.5
However,
f51: focal length of the fixed group of the fifth lens group f52: focal length of the movable group of the fifth lens group fw: focal length of the entire lens system at the wide angle end.

  Therefore, in the imaging apparatus, fluctuations in aberrations such as spherical aberration, astigmatism, and distortion are suppressed during camera shake correction.

In the zoom lens or the imaging apparatus described above, it is desirable that the movable group of the fifth lens group is configured to satisfy the following conditional expression (3).
(3) 2.0 <ft / f52 <5.0
However,
ft: The focal length of the entire lens system at the telephoto end.

  By satisfying conditional expression (3), the astigmatism on the telephoto side can be prevented from being tilted and the resolution can be prevented from deteriorating.

In the zoom lens or the imaging apparatus described above, it is preferable that the fifth lens group is configured to satisfy the following conditional expression (4).
(4) fi <f5
However,
fi: focal length of i-th lens group (i = 1 to 4)
f5: The focal length of the fifth lens group.

  By satisfying conditional expression (4), coma aberration deterioration is suppressed and resolution deterioration is also suppressed.

  Furthermore, in the zoom lens or the imaging apparatus described above, it is possible to improve the optical performance on both the wide angle side and the telephoto side by forming at least one surface of the fifth lens group as an aspheric surface.

  Furthermore, in the zoom lens or the imaging device described above, the fixed group of the fifth lens group includes a first lens having a positive refractive power, a second lens having a negative refractive power, and a negative refraction. By configuring the third lens having power with a cemented lens that is sequentially cemented from the object side to the image side, it is possible to suppress the occurrence of chromatic aberration on the wide-angle side and improve the image quality.

  In addition, in the zoom lens or the imaging apparatus described above, the movable group of the fifth lens group includes a fourth lens having a positive refractive power and a fifth lens having a negative refractive power from the object side. By using a cemented lens that is sequentially cemented to the image side, it is possible to suppress the occurrence of chromatic aberration on the wide-angle side and improve the image quality.

In the zoom lens or the imaging apparatus described above, an aperture stop is disposed on the image side of the second lens group and on the object side of the fifth lens group, and the lens group is disposed on the image side of the aperture stop. It is desirable that at least one lens group has a three-piece cemented lens constituted by cementing three lenses and satisfies the following conditional expressions (5) and (6).
(5) fm <0
(6) νm <30
However,
fm: focal length of the intermediate lens in the three-piece cemented lens νm: the Abbe number of the intermediate lens in the three-piece cemented lens.

  By satisfying conditional expression (5) and conditional expression (6), various aberrations such as spherical aberration, coma aberration, and chromatic aberration are corrected well.

Furthermore, in the zoom lens or the imaging apparatus described above, it is desirable that the three-piece cemented lens is configured to satisfy the following conditional expression (7).
(7) fs <0
However,
fs: The focal length of the three-piece cemented lens.

  By satisfying conditional expression (7), various aberrations such as spherical aberration and coma are corrected satisfactorily.

  Furthermore, in the zoom lens or the imaging apparatus described above, the chromatic aberration on the wide angle side is particularly suppressed by configuring the three-piece cemented lens in the fifth lens group.

  In the zoom lens or the imaging apparatus described above, the first lens having a positive refractive power, the second lens having a negative refractive power, and the negative lens are arranged in order from the object side to the image side. In particular, the chromatic aberration on the wide-angle side is favorably corrected.

  Furthermore, in the zoom lens or the imaging device described above, at least one surface of the three-piece cemented lens is formed as an aspheric surface, and thus spherical aberration and coma aberration on the wide-angle side are particularly favorably corrected.

Furthermore, in the zoom lens or the imaging device described above, the fifth lens group is configured to include a three-piece cemented lens having a negative refractive power and a lens group having a positive refractive power, and the following conditional expression: It is desirable to configure so as to satisfy (5) and conditional expression (6).
(5) fm <0
(6) νm <30
However,
fm: focal length of the intermediate lens in the three-piece cemented lens νm: the Abbe number of the intermediate lens in the three-piece cemented lens.

  By satisfying conditional expression (5) and conditional expression (6), various aberrations such as spherical aberration, coma aberration, and chromatic aberration are corrected well.

In order to solve the above-described problem, another zoom lens has a first lens group having a positive refractive power and a fixed first lens group, and has a negative refractive power and moves in the optical axis direction to at least change the magnification. The second lens group enabled, the third lens group fixed with positive refractive power, and the optical axis direction for correcting and focusing the focal position by zooming with positive refractive power And a fifth lens group having a positive refractive power arranged in order from the object side to the image side. The fifth lens group has a negative refractive power. A fixed group that is fixed and a movable group that has a positive refractive power and is movable in a direction substantially orthogonal to the optical axis, and is positioned in order from the object side to the image side. The fixed group includes a first lens having a positive refractive power, a second lens having a negative refractive power, and a first lens having a negative refractive power. And the movable group of the fifth lens group includes a fourth lens having a positive refractive power and a fifth lens having a negative refractive power. Is formed on the image plane by moving the movable group of the fifth lens group in a direction substantially orthogonal to the optical axis. The image can be moved in a direction substantially perpendicular to the optical axis, and is configured to satisfy the following conditional expressions (1) and (2).
(1) 0.6 <| f51 / f52 | <1.0
(2) 0.2 <fw / f52 <0.5
However,
f51: focal length of the fixed group of the fifth lens group f52: focal length of the movable group of the fifth lens group fw: focal length of the entire lens system at the wide angle end.

  Therefore, in another zoom lens, fluctuations in aberrations such as spherical aberration, astigmatism, and distortion are suppressed during camera shake correction.

Another image pickup apparatus includes a zoom lens and an image pickup element that converts an optical image formed by the zoom lens into an electrical signal in order to solve the above-described problem, and the zoom lens has a positive refractive power. A first lens group that has a fixed refractive power, a second lens group that has a negative refractive power and is movable in the optical axis direction in order to at least change the magnification, and a fixed that has a positive refractive power A third lens group, a fourth lens group having positive refracting power and movable in the optical axis direction to correct and focus the focal position by zooming, and a fifth lens having positive refracting power The fifth lens group includes a fixed group having a negative refractive power and a fixed group having a positive refractive power and substantially orthogonal to the optical axis. A movable group that is movable in a moving direction is positioned in order from the object side to the image side. A first lens having a positive refractive power, a second lens having a negative refractive power, and a third lens having a negative refractive power in order from the object side to the image side. The movable group of the fifth lens group includes a fourth lens having a positive refractive power and a fifth lens having a negative refractive power in order from the object side to the image side. An image formed on the image plane moves in a direction substantially orthogonal to the optical axis by moving the movable group of the fifth lens group in a direction substantially orthogonal to the optical axis. It is made possible to satisfy the following conditional expressions (1) and (2).
(1) 0.6 <| f51 / f52 | <1.0
(2) 0.2 <fw / f52 <0.5
However,
f51: focal length of the fixed group of the fifth lens group f52: focal length of the movable group of the fifth lens group fw: focal length of the entire lens system at the wide angle end.

  Therefore, in another imaging apparatus, fluctuations in aberrations such as spherical aberration, astigmatism, and distortion are suppressed during camera shake correction.

In another zoom lens or another imaging device described above, it is desirable that the movable group of the fifth lens group is configured to satisfy the following conditional expression (3).
(3) 2.0 <ft / f52 <5.0
However,
ft: The focal length of the entire lens system at the telephoto end.

  By satisfying conditional expression (3), the astigmatism on the telephoto side can be prevented from being tilted and the resolution can be prevented from deteriorating.

In another zoom lens or another imaging apparatus described above, it is preferable that the fifth lens group be configured to satisfy the following conditional expression (4).
(4) fi <f5
However,
fi: focal length of i-th lens group (i = 1 to 4)
f5: The focal length of the fifth lens group.

  By satisfying conditional expression (4), coma aberration deterioration is suppressed and resolution deterioration is also suppressed.

  Furthermore, in another zoom lens or another imaging apparatus described above, it is possible to improve the optical performance on both the wide-angle side and the telephoto side by forming at least one surface of the fifth lens group as an aspherical surface. .

Another zoom lens includes a first lens group having a positive refracting power and a fixed first lens group, and a second lens group having a negative refracting power and capable of moving in the optical axis direction at least for zooming. A fourth lens group having positive refractive power and being fixed; and a fourth lens group having positive refractive power and movable in the optical axis direction in order to correct and focus the focal position by zooming. A lens group and a fifth lens group having a positive refractive power are arranged in order from the object side to the image side, and are opened at a position closer to the image side than the second lens group and closer to the object side than the fifth lens group. A diaphragm is arranged, and at least one lens group among the lens groups arranged on the image side from the aperture diaphragm has a three-piece cemented lens constructed by cementing three lenses, and the following conditional expression (5) And conditional expression (6).
(5) fm <0
(6) νm <30
However,
fm: focal length of the intermediate lens in the three-piece cemented lens νm: the Abbe number of the intermediate lens in the three-piece cemented lens.

  Therefore, in another zoom lens, various aberrations such as spherical aberration, coma aberration, and chromatic aberration are corrected well.

Another image pickup apparatus includes a zoom lens and an image pickup device that converts an optical image formed by the zoom lens into an electrical signal, and the zoom lens has a fixed first lens having a positive refractive power. A second lens group having a negative refractive power and movable in the optical axis direction at least for zooming; a third lens group having a positive refractive power and fixed; and A fourth lens group that has refractive power and is movable in the optical axis direction to correct and focus the focal position by zooming, and a fifth lens group that has positive refractive power are imaged from the object side. An aperture stop disposed at a position closer to the image side than the second lens group and closer to the object side than the fifth lens group, and at least of the lens groups disposed closer to the image side than the aperture stop. Three-lens cemented lens consisting of three lenses cemented by one lens group Has a lens, in which is configured so as to satisfy the following conditional expressions (5) and (6).
(5) fm <0
(6) νm <30
However,
fm: focal length of the intermediate lens in the three-piece cemented lens νm: the Abbe number of the intermediate lens in the three-piece cemented lens.

  Therefore, in another imaging apparatus, various aberrations such as spherical aberration, coma aberration, and chromatic aberration are corrected well.

In the above-described another zoom lens or another imaging apparatus, it is preferable that the three-piece cemented lens is configured to satisfy the following conditional expression (7).
(7) fs <0
However,
fs: The focal length of the three-piece cemented lens.

  By satisfying conditional expression (7), various aberrations such as spherical aberration and coma are corrected satisfactorily.

  Further, in the above-described another zoom lens or another imaging apparatus, the chromatic aberration on the wide-angle side is particularly suppressed by configuring the three-piece cemented lens in the fifth lens group.

  Further, in the above-described another zoom lens or another image pickup apparatus, the three-piece cemented lens is arranged in order from the object side to the image side and has a negative refractive power and a first lens having a positive refractive power. By configuring with the second lens and the third lens having a negative refractive power, chromatic aberration on the wide-angle side is particularly well corrected.

  In addition, in the above-described another zoom lens or another imaging apparatus, at least one surface of the three-piece cemented lens is formed as an aspheric surface, so that spherical aberration and coma on the wide-angle side are particularly good. It is corrected.

Still another zoom lens includes a first lens group having a positive refractive power and a fixed first lens group, and a second lens group having a negative refractive power and capable of moving in the optical axis direction in order to at least change the magnification. A fourth lens group having positive refractive power and being fixed; and a fourth lens group having positive refractive power and movable in the optical axis direction in order to correct and focus the focal position by zooming. A lens group and a fifth lens group having a positive refractive power are arranged in order from the object side to the image side. The fifth lens group has a three-piece cemented lens having a negative refractive power and a positive refractive power. And the following conditional expression (5) and conditional expression (6) are satisfied.
(5) fm <0
(6) νm <30
However,
fm: focal length of the intermediate lens in the three-piece cemented lens νm: the Abbe number of the intermediate lens in the three-piece cemented lens.

  Therefore, in another zoom lens, various aberrations such as spherical aberration, coma aberration, and chromatic aberration are corrected well.

Still another image pickup apparatus includes a zoom lens and an image pickup element that converts an optical image formed by the zoom lens into an electric signal, and the zoom lens has a first lens that has a positive refractive power and is fixed. A second lens group having a negative refractive power and movable in the optical axis direction at least for zooming; a third lens group having a positive refractive power and fixed; and A fourth lens group that has refractive power and is movable in the optical axis direction to correct and focus the focal position by zooming, and a fifth lens group that has positive refractive power are imaged from the object side. The fifth lens group includes a three-piece cemented lens having a negative refractive power and a lens group having a positive refractive power. The following conditional expression (5) and This is configured to satisfy the conditional expression (6).
(5) fm <0
(6) νm <30
However,
fm: focal length of the intermediate lens in the three-piece cemented lens νm: the Abbe number of the intermediate lens in the three-piece cemented lens.

  Therefore, in another imaging device, various aberrations such as spherical aberration, coma aberration, and chromatic aberration are corrected well.

  In the above-described another zoom lens or still another imaging device, the first lens having a positive refractive power and the second lens having a negative refractive power are arranged in order from the object side to the image side. In particular, the chromatic aberration on the wide-angle side is favorably corrected by comprising the above lens and the third lens having negative refractive power.

  Further, in the above-described further zoom lens or further image pickup apparatus, at least one surface of the three-piece cemented lens is formed as an aspheric surface, so that particularly spherical aberration and coma aberration on the wide-angle side are favorably corrected. Is done.

  According to the present invention, it is possible to suppress degradation of optical performance, and it is possible to provide a zoom lens or an imaging device that is small in size, high in image quality, and high in magnification.

  The best mode for carrying out the zoom lens and the imaging apparatus of the present invention will be described below with reference to the drawings.

  First, the zoom lens of the present invention will be described.

  The zoom lens according to the present invention includes a first lens group having a positive refractive power and a fixed first lens group, and a second lens group having a negative refractive power and capable of moving in the optical axis direction at least in order to perform zooming. A third lens group having a positive refracting power and a fixed third lens group, and a fourth lens having a positive refracting power and movable in the optical axis direction in order to correct and focus the focal position by zooming And a fifth lens group having a positive refractive power are arranged in order from the object side to the image side. The fifth lens group includes a fixed group having a negative refractive power and a positive group. A movable group that has refractive power and is movable in a direction substantially orthogonal to the optical axis is positioned in order from the object side to the image side, and the movable group of the fifth lens group is in a direction substantially orthogonal to the optical axis. By being moved, an image formed on the image plane can be moved in a direction substantially orthogonal to the optical axis.

  As described above, the zoom lens of the present invention is configured to correct image blur due to camera shake or the like by moving the movable group of the fifth lens group in a direction substantially orthogonal to the optical axis.

  Therefore, in the zoom lens according to the present invention, by using the movable group of the fifth lens group located closest to the image side for camera shake correction, the lens group for camera shake correction is provided in a portion where the effective diameter of the light beam is relatively small. Therefore, it is possible to avoid an increase in the size of the lens barrel.

  In addition, since the movable group of the fifth lens group is located closest to the image side, there is little influence on fluctuations in the light beam position in other lens groups during camera shake correction, and further enlargement of the lens barrel is prevented. It becomes possible.

  Further, there are few restrictions on securing the space on both sides in the optical axis direction of the movable group of the fifth lens group, and it becomes possible to improve the optical performance and reduce the size of the lens barrel.

The zoom lens of the present invention is configured to satisfy the following conditional expressions (1) and (2).
(1) 0.6 <| f51 / f52 | <1.0
(2) 0.2 <fw / f52 <0.5
However,
f51: focal length of the fixed group of the fifth lens group f52: focal length of the movable group of the fifth lens group fw: focal length of the entire lens system at the wide angle end.

  Conditional expression (1) defines the ratio of the focal length f51 of the fixed group of the fifth lens group and the focal length f52 of the movable group of the fifth lens group, that is, the range of the refractive power ratio.

  If the value of | f51 / f52 | in the conditional expression (1) exceeds the upper limit value, the refractive power of the movable group of the fifth lens group becomes too strong, and the optical performance during camera shake correction is greatly deteriorated. That is, when a movable group having a strong refractive power is operated for camera shake correction, in particular, coma is deteriorated and the resolution is greatly lowered as the image height is increased. Further, if the value of | f51 / f52 | in the conditional expression (1) exceeds the upper limit value, the distortion aberration is deteriorated and the image is greatly distorted asymmetrically.

  On the contrary, if the value of | f51 / f52 | in the conditional expression (1) exceeds the lower limit value, the refractive power of the fixed group of the fifth lens group becomes too strong, and the luminous flux divergence action in the fifth lens group becomes large. The overall length of the entire zoom lens system becomes longer, and the lens barrel becomes larger.

  Conditional expression (2) is an expression that defines the ratio of the focal length fw of the entire lens system at the wide-angle end to the focal length f52 of the movable group of the fifth lens group, that is, the range of the refractive power ratio.

  If the value of fw / f52 in the conditional expression (2) exceeds the upper limit value, the refractive power of the movable group of the fifth lens group becomes too strong, and in particular, the optical performance on the wide angle side is greatly deteriorated. That is, the spherical aberration on the wide-angle side is overcorrected and falls to the under side, or the coma aberration deteriorates, resulting in degradation of resolution.

  On the contrary, if the value of fw / f52 in conditional expression (2) exceeds the lower limit, the refractive power of the movable group of the fifth lens group becomes too weak, and in particular, the optical performance on the wide angle side is greatly deteriorated. That is, the spherical aberration on the wide angle side falls to the over side due to insufficient correction, and the coma aberration deteriorates, resulting in degradation of resolution.

  Therefore, the zoom lens according to the present invention satisfies the conditional expressions (1) and (2), thereby improving the optical performance at the time of camera shake correction, optimizing the aberration correction, and shortening the total length of the entire zoom lens system. The lens barrel can be reduced in size and resolution can be prevented from being deteriorated.

In the zoom lens according to the embodiment of the present invention, it is preferable that the following conditional expression (3) is satisfied.
(3) 2.0 <ft / f52 <5.0
However,
ft: The focal length of the entire lens system at the telephoto end.

  Conditional expression (3) defines the ratio of the focal length ft of the entire lens system at the telephoto end to the focal length f52 of the movable group of the fifth lens group, that is, the range of the refractive power ratio.

  If the value of ft / f52 in conditional expression (3) exceeds the upper limit value, the refractive power of the movable group of the fifth lens group becomes too strong, and in particular, the optical performance on the telephoto side is greatly reduced. That is, the astigmatism on the telephoto side falls to the under side or the coma aberration deteriorates, resulting in degradation of resolution.

  Conversely, if the value of ft / f52 in conditional expression (3) exceeds the lower limit, the refractive power of the movable group of the fifth lens group becomes too weak, and in particular, the optical performance on the telephoto side is greatly reduced. That is, the astigmatism on the telephoto side falls to the over side, or the coma aberration deteriorates, resulting in degradation of resolution.

  Therefore, when the zoom lens satisfies the conditional expression (3), it is possible to suppress deterioration of the optical performance particularly on the telephoto side.

In the zoom lens according to the embodiment of the present invention, it is preferable that the following conditional expression (4) is satisfied.
(4) fi <f5
However,
fi: focal length of i-th lens group (i = 1 to 4)
f5: The focal length of the fifth lens group.

  Conditional expression (4) is the relationship between the focal length f5 of the fifth lens group and the focal length fi (i = 1 to 4) of the other lens groups (first lens group to fourth lens group), that is, It is a formula that defines the relationship of refractive power.

  When the value of the focal length f5 of the fifth lens group in the conditional expression (4) exceeds the value of the focal length fi of the i-th lens group, the refractive power of the fifth lens group becomes too strong. The performance is greatly deteriorated. That is, since the refractive power of the movable group having positive refractive power in the fifth lens group becomes strong, especially when the movable group having strong refractive power moves for camera shake correction, the coma aberration deteriorates, and the image height increases. As resolution increases, the resolution is greatly reduced. Further, if the value of the focal length f5 of the fifth lens group in the conditional expression (4) exceeds the value of the focal length fi of the i-th lens group, the distortion is deteriorated and the image is greatly distorted asymmetrically.

  Therefore, when the zoom lens satisfies the conditional expression (4), it is possible to suppress the deterioration of the optical performance particularly during the camera shake correction.

  In the zoom lens according to the embodiment of the present invention, it is preferable that at least one surface of the fifth lens group is formed as an aspheric surface.

  As a result, it is possible to satisfactorily correct spherical aberration and coma particularly on the wide angle side. Further, by forming at least one surface of the fifth lens group as an aspherical surface, on the telephoto side, it is possible to suppress deterioration of performance particularly when the movable group is moved during camera shake correction. Therefore, by forming at least one surface of the fifth lens group as an aspherical surface, it is possible to improve the optical performance on both the wide angle side and the telephoto side.

  In the zoom lens according to the embodiment of the present invention, the fixed group of the fifth lens group includes a first lens having a positive refractive power, a second lens having a negative refractive power, and a negative refraction. It is preferable to form a cemented lens (three-lens cemented lens) in which a third lens having power is cemented in order from the object side to the image side.

  Thereby, in particular, it is possible to suppress the occurrence of chromatic aberration on the wide angle side and improve the image quality.

  In the zoom lens according to the embodiment of the present invention, the movable group of the fifth lens group includes the fourth lens having a positive refractive power and the fifth lens having a negative refractive power on the object side. It is preferable that the lens is constituted by a cemented lens that is sequentially cemented from the image side to the image side.

  Thereby, in particular, it is possible to suppress the occurrence of chromatic aberration on the wide angle side and improve the image quality.

  By the way, in recent years, with the widespread use of high-definition image quality monitors, there has been an increasing demand for higher image quality for small-sized imaging devices such as video cameras. It is an issue. Therefore, from the viewpoint of chromatic aberration and resolution on the wide angle side, high-precision aberration correction such as correction of longitudinal chromatic aberration and lateral chromatic aberration is particularly required.

  Therefore, the zoom lens according to the present invention can be configured as follows, in particular, in order to improve the image quality on the wide angle side.

In the zoom lens according to an embodiment of the present invention, it is preferable that the three cemented lenses in the fifth lens group are configured to satisfy the following conditional expressions (5) and (6).
(5) fm <0
(6) νm <30
However,
fm: focal length of the intermediate lens in the three-piece cemented lens νm: the Abbe number of the intermediate lens in the three-piece cemented lens.

  Conditional expression (5) is an expression for appropriately setting the focal length of the intermediate lens in the triplet cemented lens of the fifth lens group.

  If the value of fm in conditional expression (5) exceeds the upper limit value, the positive refractive power of the three-piece cemented lens in the fifth lens group becomes too strong, and various aberrations such as spherical aberration and coma become worse. Will come down.

  Conditional expression (6) is an expression for appropriately setting the Abbe number of the intermediate lens in the triplet cemented lens of the fifth lens group.

  If the value of νm in conditional expression (6) exceeds the upper limit value, the condition for correcting chromatic aberration by the three-piece cemented lens in the fifth lens group will be lost, and the chromatic aberration of the entire zoom lens system will deteriorate. The condition for correcting chromatic aberration is a condition determined by the relationship of correcting chromatic aberration and the relationship of refractive power. If this condition is not met, a high-quality image cannot be obtained.

  Therefore, when the zoom lens satisfies the conditional expressions (5) and (6), various aberrations such as spherical aberration and coma are corrected well, and the occurrence of chromatic aberration is suppressed, thereby improving the image quality. be able to.

  The three-piece cemented lens for correcting the chromatic aberration described above needs to be arranged on the image side from the aperture stop, in particular, in order to have a configuration that contributes to an improvement in image quality on the wide angle side. The aperture stop is arranged at a position closer to the image side than the second lens group and closer to the object side than the fifth lens group.

  For example, in the case where the aperture stop is arranged on the object side of the third lens group, the light beam incident through the first lens group is reduced on the side close to the object, and the first lens group The diameter can be reduced. For example, when the aperture stop is arranged on the image side of the third lens group or the fourth lens group, the light beam incident through the first lens group is narrowed on the side close to the image. Thus, the overall length of the entire zoom lens system can be shortened.

In the zoom lens according to the embodiment of the present invention, it is preferable that the three cemented lenses in the fifth lens group satisfy the following conditional expression (7).
(7) fs <0
However,
fs: The focal length of the three-piece cemented lens.

  Conditional expression (7) is an expression for appropriately setting the focal length of the three-piece cemented lens in the fifth lens group.

  When the value of fs in conditional expression (7) exceeds the upper limit, the positive refractive power of the three-piece cemented lens in the fifth lens group becomes too strong, and various aberrations such as spherical aberration and coma deteriorate, resulting in image quality. Will come down.

  Therefore, when the zoom lens satisfies the conditional expression (7), various aberrations such as spherical aberration and coma are corrected well, and the image quality can be improved.

  In the zoom lens according to the embodiment of the present invention, the three-piece cemented lens is configured in the fifth lens group.

  Thereby, in particular, it is possible to suppress chromatic aberration on the wide-angle side and improve image quality.

  In the above, an example in which the three-piece cemented lens is configured in the fifth lens group is shown. However, if the three-piece cemented lens is arranged on the image side of the aperture stop, It is also possible to constitute a four-lens group. This also makes it possible to suppress chromatic aberration on the wide angle side and improve image quality.

  In the zoom lens according to the embodiment of the present invention, as described above, the three-lens cemented lens is arranged in order from the object side to the image side, the first lens having positive refractive power, and the negative lens. The second lens having a refractive power of 3 and the third lens having a negative refractive power.

  Therefore, in particular, the chromatic aberration on the wide-angle side is corrected well, and the image quality can be improved.

  Furthermore, at least one surface of the three-lens cemented lens in the fifth lens group is formed of an aspherical surface. Thereby, in particular, spherical aberration and coma aberration on the wide angle side can be corrected well, and image quality can be improved.

  As described above, in the zoom lens of the present invention, by appropriately setting the configuration of each lens and each conditional expression, it is possible to suppress deterioration of optical performance, and it is small and has high image quality. A zoom lens with a high magnification can be provided.

  Next, specific embodiments of the zoom lens according to the present invention and numerical examples obtained by applying specific numerical values to the embodiments will be described with reference to the drawings and tables.

  The meanings of the symbols shown in the following description are as shown below.

  “Ri” is the radius of curvature of the i-th surface (i-th surface) from the object side to the image side, and “Di” is the surface distance between the i-th surface and the (i + 1) -th surface (lens of the lens). "Ni" is the refractive index of the d-line (wavelength 587.6 nm) of the material constituting the i-th lens, and "νi" is the d-line (wavelength 587) of the material constituting the i-th lens. Abbe number at .6 nm). Regarding the curvature radius, “∞” indicates that the surface is a flat surface, and regarding the surface interval, “Variable” indicates that the surface interval is a variable interval.

Some lenses used in each numerical example have an aspheric lens surface. In the aspherical shape, “Xi” is the coordinate in the optical axis direction of the aspheric surface on the i-th surface, “Ci” is the paraxial curvature (reciprocal of the radius of curvature) on the i-th surface, and “Y” is the optical axis. If the distance from
Xi = (Ci · Y ² ) / {1+ (1−Ci ² · Y ² ) ^1/2 } + A4 · Y ⁴ + A6 · Y ⁶ + A8 · Y ⁸ + A10 · Y ¹⁰
Shall be defined by A4, A6, A8, and A10 are aspheric coefficients of the respective orders (4th order, 6th order, 8th order, and 10th order).

  FIG. 1 is a diagram showing a lens configuration of a zoom lens 1 according to the first embodiment of the present invention.

  As shown in FIG. 1, the zoom lens 1 according to the first embodiment is composed of 14 lenses.

  The first lens group GR1 has a positive refractive power as a whole, and includes three lenses, a lens L1, a lens L2, and a lens L3. The lens L1 and the lens L2 constitute a cemented lens having a cemented surface R2 in which a concave surface and a convex surface having the same radius of curvature facing the image side of the lens L1 and the object side of the lens L2 are cemented.

  The second lens group GR2 has a negative refracting power as a whole and includes three lenses, a lens L4, a lens L5, and a lens L6. The second lens group GR2 is movable in the optical axis direction and mainly has a function of performing zooming. The lens L5 and the lens L6 constitute a cemented lens having a cemented surface R9 in which a concave surface and a convex surface having the same radius of curvature facing the image side of the lens L5 and the object side of the lens L6 are cemented. The lens L4 has an aspherical concave surface on the image side.

  The third lens group GR3 is configured by a single lens L7 having a positive refractive power. The lens L7 is a meniscus lens having a convex surface directed toward the object side, and both the object side surface and the image side surface are formed as aspherical surfaces.

  The fourth lens group GR4 has a positive refractive power as a whole, and is constituted by two lenses, a lens L8 and a lens L9. The fourth lens group GR4 is movable in the optical axis direction, and has a function of correcting the focal position by zooming and focusing. The lens L8 and the lens L9 constitute a cemented lens having a cemented surface R15 in which a concave surface and a convex surface having the same radius of curvature facing the image side of the lens L8 and the object side of the lens L9 are cemented. The image side surface of the lens L9 is formed as an aspherical surface.

  The fifth lens group GR5 has a positive refracting power as a whole, and includes five lenses of a lens L10, a lens L11, a lens L12, a lens L13, and a lens L14. The fifth lens group GR5 includes a fixed group GR5-1 having a negative refractive power, the lens L10, the lens 11, and the lens L12 and having a fixed position, and a lens having a positive refractive power. A movable group GR5-2, which includes two lenses L13 and L14 and is movable in a direction substantially orthogonal to the optical axis, is arranged in order from the object side to the image side.

  By moving the movable group GR5-2 of the fifth lens group GR5 located closest to the image side in a direction substantially orthogonal to the optical axis, the image formed on the image plane is moved in a direction substantially orthogonal to the optical axis. It is possible to make it.

  The lens L10, the lens L11, and the lens L12 constitute a three-piece cemented lens in which surfaces having the same radius of curvature facing the image side and the object side are cemented, and each has a cemented surface R18 and a cemented surface R19. The image side surface of the lens L12 is aspheric.

  The lens L13 and the lens L14 constitute a cemented lens having a cemented surface R22 in which a concave surface and a convex surface having the same radius of curvature facing the image side of the lens L13 and the object side of the lens L14 are cemented. The object side surface of the lens 13 is formed as an aspherical surface.

  A diaphragm IR (diaphragm surface R11) is disposed between the second lens group GR2 and the third lens group GR3, and the diaphragm IR is fixed.

  A filter FL (filter surfaces R24 and R25) is disposed between the fifth lens group GR5 and the image plane IMG.

  The zoom lens 1 satisfies the conditional expressions (1) to (7).

  Table 1 shows lens data of Numerical Example 1 in which specific numerical values are applied to the zoom lens 1 according to the first embodiment.

  When zooming from the wide-angle end state to the telephoto end state in the zoom lens 1, the surface distance D5 between the first lens group GR1 and the second lens group GR2, the second lens group GR2, and the third lens group (aperture stop) SP) The surface distance D10 between GR3, the surface distance D13 between the third lens group GR3 and the fourth lens group GR4, and the surface distance D16 between the fourth lens group GR4 and the fifth lens group GR5 are changed. To do. Therefore, the wide-angle end state (focal length f = 1.00), the intermediate focal length state (focal length f = 5.53), and the telephoto end state (focal length f = 10.93) of each surface interval in Numerical Example 1. Table 2 shows values when the object distance is infinity.

  In the zoom lens 1, the image side surface (R7) of the lens L4 of the second lens group GR2, both surfaces (R12, R13) of the lens L7 of the third lens group GR3, and the image side of the lens L9 of the fourth lens group GR4. The surface (R16), the image-side surface (R20) of the lens L12 of the fifth lens group GR5, and the object-side surface (R21) of the lens L12 of the fifth lens group GR5 are aspheric. Therefore, Table 3 shows the fourth, sixth, eighth and tenth aspheric coefficients A4, A6, A8 and A10 of the aspheric surface in Numerical Example 1.

In Table 3 and the table showing the aspherical coefficient described later, “E-i” represents an exponential expression with 10 as the base, that is, “10 ⁻ⁱ ”, for example, “0.12345E-05”. Represents “0.12345 × 10 ⁻⁵ ”.

  Table 4 shows the values of the conditional expressions (1) to (7) in the zoom lens 1, that is, the focal length (fi) of each lens group GRi (i = 1 to 5), and the fixed group of the fifth lens group. The focal length (f51) of GR5-1, the focal length (f52) of the movable group GR5-2 of the fifth lens group, the focal length (fw) of the entire lens system at the wide-angle end, and the focal length (fw) of the entire lens system at the telephoto end ( ft), focal length (fm) of the intermediate lens in the three-piece cemented lens of the fifth lens group, Abbe number (νm) of the intermediate lens in the three-piece cemented lens of the fifth lens group, three-piece cemented lens of the fifth lens group The focal length (fs), open F value (Fno.), Angle of view (2ω), and refractive power ratio (| f51 / f52 |, fw / f52, ft / f52) are shown.

  2 to 4 are graphs showing various aberrations in the infinite focus state in Numerical Example 1, FIG. 2 is a wide angle end state, FIG. 3 is an intermediate focal length state, and FIG. 4 is a telephoto end state. Various aberration diagrams are shown.

  In the spherical aberration diagrams shown in FIGS. 2 to 4, the solid line shows the value of the d-line (wavelength 587.6 nm), the dotted line shows the value of the g-line (wavelength 435.8 nm), and the dashed line shows the C-line (wavelength). The value of 656.3 nm) is shown respectively. In the astigmatism diagrams shown in FIGS. 2 to 4, values on the sagittal image plane are indicated by solid lines, and values on the meridional image plane are indicated by broken lines.

  From each aberration diagram, it is clear that Numerical Example 1 has excellent imaging performance with various aberrations corrected well.

  FIG. 5 is a diagram showing a lens configuration of the zoom lens 2 according to the second embodiment of the present invention.

  The zoom lens 2 in the second embodiment is composed of 14 lenses as shown in FIG.

  The first lens group GR1 has a positive refractive power as a whole, and includes three lenses, a lens L1, a lens L2, and a lens L3. The lens L1 and the lens L2 constitute a cemented lens having a cemented surface R2 in which a concave surface and a convex surface having the same radius of curvature facing the image side of the lens L1 and the object side of the lens L2 are cemented.

  The second lens group GR2 has a negative refracting power as a whole and includes three lenses, a lens L4, a lens L5, and a lens L6. The second lens group GR2 is movable in the optical axis direction and mainly has a function of performing zooming. The lens L5 and the lens L6 constitute a cemented lens having a cemented surface R9 in which a concave surface and a convex surface having the same radius of curvature facing the image side of the lens L5 and the object side of the lens L6 are cemented. The lens L4 has an aspherical concave surface on the image side.

  The third lens group GR3 is configured by a single lens L7 having a positive refractive power. The lens L7 is a meniscus lens having a convex surface directed toward the object side, and both the object side surface and the image side surface are formed as aspherical surfaces.

  The fourth lens group GR4 has a positive refractive power as a whole, and is constituted by two lenses, a lens L8 and a lens L9. The fourth lens group GR4 is movable in the optical axis direction, and has a function of correcting the focal position by zooming and focusing. The lens L8 and the lens L9 constitute a cemented lens having a cemented surface R15 in which a concave surface and a convex surface having the same radius of curvature facing the image side of the lens L8 and the object side of the lens L9 are cemented. The image side surface of the lens L9 is formed as an aspherical surface.

  The fifth lens group GR5 has a positive refracting power as a whole, and includes five lenses of a lens L10, a lens L11, a lens L12, a lens L13, and a lens L14. The fifth lens group GR5 includes a fixed group GR5-1 having a negative refractive power, the lens L10, the lens 11, and the lens L12 and having a fixed position, and a lens having a positive refractive power. A movable group GR5-2, which includes two lenses L13 and L14 and is movable in a direction substantially orthogonal to the optical axis, is arranged in order from the object side to the image side.

  By moving the movable group GR5-2 of the fifth lens group GR5 located closest to the image side in a direction substantially orthogonal to the optical axis, the image formed on the image plane is moved in a direction substantially orthogonal to the optical axis. It is possible to make it.

  The lens L10, the lens L11, and the lens L12 constitute a three-piece cemented lens in which surfaces having the same radius of curvature facing the image side and the object side are cemented, and each has a cemented surface R18 and a cemented surface R19. The image side surface of the lens L12 is aspheric.

  The lens L13 and the lens L14 constitute a cemented lens having a cemented surface R22 in which a concave surface and a convex surface having the same radius of curvature facing the image side of the lens L13 and the object side of the lens L14 are cemented. The object side surface of the lens 13 is formed as an aspherical surface.

  A diaphragm IR (diaphragm surface R11) is disposed between the second lens group GR2 and the third lens group GR3, and the diaphragm IR is fixed.

  A filter FL (filter surfaces R24 and R25) is disposed between the fifth lens group GR5 and the image plane IMG.

  The zoom lens 2 satisfies the conditional expressions (1) to (7).

  Table 5 shows lens data of Numerical Example 2 in which specific numerical values are applied to the zoom lens 2 according to the second embodiment.

  When zooming from the wide-angle end state to the telephoto end state in the zoom lens 2, the surface distance D5 between the first lens group GR1 and the second lens group GR2, the second lens group GR2, and the third lens group (aperture stop) SP) The surface distance D10 between GR3, the surface distance D13 between the third lens group GR3 and the fourth lens group GR4, and the surface distance D16 between the fourth lens group GR4 and the fifth lens group GR5 are changed. To do. Therefore, the wide-angle end state (focal length f = 1.00), the intermediate focal length state (focal length f = 5.84), and the telephoto end state (focal length f = 10.92) of each surface interval in Numerical Example 2. Table 6 shows values when the object distance is infinity.

  In the zoom lens 2, the image side surface (R7) of the lens L4 of the second lens group GR2, the both surfaces (R12, R13) of the lens L7 of the third lens group GR3, and the image side of the lens L9 of the fourth lens group GR4. The surface (R16), the image-side surface (R20) of the lens L12 of the fifth lens group GR5, and the object-side surface (R21) of the lens L12 of the fifth lens group GR5 are aspheric. Therefore, Table 7 shows fourth-order, sixth-order, eighth-order, and tenth-order aspheric coefficients A4, A6, A8, and A10 in Numerical Example 1.

  Table 8 shows the values of the conditional expressions (1) to (7) in the zoom lens 2, that is, the focal length (fi) of each lens group GRi (i = 1 to 5), and the fixed group of the fifth lens group. The focal length (f51) of GR5-1, the focal length (f52) of the movable group GR5-2 of the fifth lens group, the focal length (fw) of the entire lens system at the wide-angle end, and the focal length (fw) of the entire lens system at the telephoto end ( ft), focal length (fm) of the intermediate lens in the three-piece cemented lens of the fifth lens group, Abbe number (νm) of the intermediate lens in the three-piece cemented lens of the fifth lens group, three-piece cemented lens of the fifth lens group The focal length (fs), open F value (Fno.), Angle of view (2ω), and refractive power ratio (| f51 / f52 |, fw / f52, ft / f52) are shown.

  6 to 8 are graphs showing various aberrations in the infinite focus state in Numerical Example 2. FIG. 6 is a wide-angle end state, FIG. 7 is an intermediate focal length state, and FIG. 8 is a telephoto end state. Various aberration diagrams are shown.

  In the spherical aberration diagrams shown in FIGS. 6 to 8, the solid line shows the value of d-line (wavelength 587.6 nm), the dotted line shows the value of g-line (wavelength 435.8 nm), and the alternate long and short dash line shows C-line (wavelength). The value of 656.3 nm) is shown respectively. Further, in the astigmatism diagrams shown in FIGS. 6 to 8, values on the sagittal image plane are shown by solid lines, and values on the meridional image plane are shown by broken lines.

  From each aberration diagram, it is clear that Numerical Example 2 has excellent imaging performance with various aberrations corrected well.

  FIG. 9 is a diagram showing a lens configuration of the zoom lens 3 according to the third embodiment of the present invention.

  The zoom lens 3 according to the third embodiment is composed of 14 lenses as shown in FIG.

  The first lens group GR1 has a positive refractive power as a whole, and includes three lenses, a lens L1, a lens L2, and a lens L3. The lens L1 and the lens L2 constitute a cemented lens having a cemented surface R2 in which a concave surface and a convex surface having the same radius of curvature facing the image side of the lens L1 and the object side of the lens L2 are cemented.

  The second lens group GR2 has a negative refracting power as a whole and includes three lenses, a lens L4, a lens L5, and a lens L6. The second lens group GR2 is movable in the optical axis direction and mainly has a function of performing zooming. The lens L5 and the lens L6 constitute a cemented lens having a cemented surface R9 in which a concave surface and a convex surface having the same radius of curvature facing the image side of the lens L5 and the object side of the lens L6 are cemented. The lens L4 has an aspherical concave surface on the image side.

  The third lens group GR3 is configured by a single lens L7 having a positive refractive power. The lens L7 is a meniscus lens having a convex surface directed toward the object side, and both the object side surface and the image side surface are formed as aspherical surfaces.

  The fourth lens group GR4 has a positive refractive power as a whole, and is constituted by two lenses, a lens L8 and a lens L9. The fourth lens group GR4 is movable in the optical axis direction, and has a function of correcting the focal position by zooming and focusing. The lens L8 and the lens L9 constitute a cemented lens having a cemented surface R15 in which a concave surface and a convex surface having the same radius of curvature facing the image side of the lens L8 and the object side of the lens L9 are cemented. The image side surface of the lens L9 is formed as an aspherical surface.

  The fifth lens group GR5 has a positive refracting power as a whole, and includes five lenses of a lens L10, a lens L11, a lens L12, a lens L13, and a lens L14. The fifth lens group GR5 includes a fixed group GR5-1 having a negative refractive power, the lens L10, the lens 11, and the lens L12 and having a fixed position, and a lens having a positive refractive power. A movable group GR5-2, which includes two lenses L13 and L14 and is movable in a direction substantially orthogonal to the optical axis, is arranged in order from the object side to the image side.

  By moving the movable group GR5-2 of the fifth lens group GR5 located closest to the image side in a direction substantially orthogonal to the optical axis, the image formed on the image plane is moved in a direction substantially orthogonal to the optical axis. It is possible to make it.

  The lens L10, the lens L11, and the lens L12 constitute a three-piece cemented lens in which surfaces having the same radius of curvature facing the image side and the object side are cemented, and each has a cemented surface R18 and a cemented surface R19. The image side surface of the lens L12 is aspheric.

  The lens L13 and the lens L14 constitute a cemented lens having a cemented surface R22 in which a concave surface and a convex surface having the same radius of curvature facing the image side of the lens L13 and the object side of the lens L14 are cemented. The object side surface of the lens 13 is formed as an aspherical surface.

  A diaphragm IR (diaphragm surface R11) is disposed between the second lens group GR2 and the third lens group GR3, and the diaphragm IR is fixed.

  A filter FL (filter surfaces R24 and R25) is disposed between the fifth lens group GR5 and the image plane IMG.

  The zoom lens 3 satisfies the conditional expressions (1) to (7).

  Table 9 shows lens data of a numerical example 3 in which specific numerical values are applied to the zoom lens 3 according to the third embodiment.

  When zooming from the wide-angle end state to the telephoto end state in the zoom lens 3, the surface distance D5 between the first lens group GR1 and the second lens group GR2, the second lens group GR2, and the third lens group (aperture stop) SP) The surface distance D10 between GR3, the surface distance D13 between the third lens group GR3 and the fourth lens group GR4, and the surface distance D16 between the fourth lens group GR4 and the fifth lens group GR5 are changed. To do. Therefore, the wide-angle end state (focal length f = 1.00), the intermediate focal length state (focal length f = 5.58), and the telephoto end state (focal length f = 10.93) of each surface interval in Numerical Example 3. Table 10 shows values when the object distance is infinity.

  In the zoom lens 3, the image side surface (R7) of the lens L4 of the second lens group GR2, the both surfaces (R12, R13) of the lens L7 of the third lens group GR3, and the image side of the lens L9 of the fourth lens group GR4. The surface (R16), the image-side surface (R20) of the lens L12 of the fifth lens group GR5, and the object-side surface (R21) of the lens L12 of the fifth lens group GR5 are aspheric. Therefore, Table 11 shows the fourth-order, sixth-order, eighth-order, and tenth-order aspheric coefficients A4, A6, A8, and A10 of Numerical Example 1.

  Table 12 shows the values of the conditional expressions (1) to (7) in the zoom lens 3, that is, the focal length (fi) of each lens group GRi (i = 1 to 5), and the fixed group of the fifth lens group. The focal length (f51) of GR5-1, the focal length (f52) of the movable group GR5-2 of the fifth lens group, the focal length (fw) of the entire lens system at the wide-angle end, and the focal length (fw) of the entire lens system at the telephoto end ( ft), focal length (fm) of the intermediate lens in the three-piece cemented lens of the fifth lens group, Abbe number (νm) of the intermediate lens in the three-piece cemented lens of the fifth lens group, three-piece cemented lens of the fifth lens group The focal length (fs), open F value (Fno.), Angle of view (2ω), and refractive power ratio (| f51 / f52 |, fw / f52, ft / f52) are shown.

  FIGS. 10 to 12 are graphs showing various aberrations in the infinite focus state in Numerical Example 3. FIG. 10 is a wide-angle end state, FIG. 11 is an intermediate focal length state, and FIG. 12 is a telephoto end state. Various aberration diagrams are shown.

  In the spherical aberration diagrams shown in FIGS. 10 to 12, the solid line shows the value of the d-line (wavelength 587.6 nm), the dotted line shows the value of the g-line (wavelength 435.8 nm), and the dashed line shows the C-line (wavelength). The value of 656.3 nm) is shown respectively. In the astigmatism diagrams shown in FIG. 10 to FIG. 12, values on the sagittal image plane are indicated by solid lines, and values on the meridional image plane are indicated by broken lines.

  From each aberration diagram, it is clear that Numerical Example 3 has excellent imaging performance with various aberrations corrected well.

  Next, the imaging apparatus of the present invention will be described.

  The imaging device of the present invention is an imaging device that includes a zoom lens and an imaging device that converts an optical image formed by the zoom lens into an electrical signal.

  The zoom lens provided in the image pickup apparatus includes a first lens group having a positive refractive power and a fixed first lens group, and a first lens group having a negative refractive power and capable of moving in the optical axis direction at least in order to perform zooming. Two lens groups, a third lens group having a positive refractive power and a fixed third lens group, and a positive refractive power and movable in the optical axis direction to correct and focus the focal position by zooming. The fourth lens group and the fifth lens group having a positive refractive power are arranged in order from the object side to the image side, and the fifth lens group is a fixed group having a negative refractive power and fixed. And a movable group that has a positive refractive power and is movable in a direction substantially perpendicular to the optical axis, is sequentially positioned from the object side to the image side, and the movable group of the fifth lens group is substantially aligned with the optical axis. By moving in an orthogonal direction, an image formed on the image plane can be moved in a direction substantially orthogonal to the optical axis.

  Therefore, in the imaging apparatus according to the present invention, by using the movable group of the fifth lens group located closest to the image side for camera shake correction, the lens group for camera shake correction is provided in a portion where the effective diameter of the light beam is relatively small. Therefore, it is possible to avoid an increase in the size of the imaging device.

  In addition, since the movable group of the fifth lens group is positioned closest to the image side, there is little influence on fluctuations in the light beam position in other lens groups during camera shake correction, and further enlargement of the imaging device can be prevented. Is possible.

  Further, there are few restrictions on securing the space on both sides in the optical axis direction of the movable group of the fifth lens group, and it becomes possible to improve the optical performance and reduce the size of the imaging device.

  The first lens group has a positive refractive power as a whole and is composed of three lenses. The two lenses located on the object side constitute a cemented lens.

  The second lens group has a negative refractive power as a whole and is composed of three lenses. The second lens group is movable in the optical axis direction and mainly has a function of performing zooming. The two lenses located on the image side constitute a cemented lens. In the second lens group, the image-side surface of the lens located on the object side is formed as an aspheric surface having a concave surface.

  The third lens group is composed of a single lens having a positive refractive power. The lens of the third lens group is a meniscus lens having a convex surface facing the object side, and both the object side surface and the image side surface are aspherical.

  The fourth lens group has a positive refractive power as a whole, and is constituted by two lenses. The fourth lens group is movable in the optical axis direction, and has a function of correcting the focus position by zooming and focusing. The two lenses in the fourth lens group constitute a cemented lens. The image side surface of the lens located on the image side of the fourth lens group is formed as an aspherical surface.

  The fifth lens group has a positive refractive power as a whole, and is constituted by five lenses. The fifth lens group GR5 is composed of three lenses having negative refractive power and fixed in position, and is composed of two lenses having positive refractive power and is substantially orthogonal to the optical axis. A movable group that is movable in the direction is arranged in order from the object side to the image side.

The imaging apparatus configured as described above is configured such that the zoom lens satisfies the following conditional expressions (1) and (2).
(1) 0.6 <| f51 / f52 | <1.0
(2) 0.2 <fw / f52 <0.5
However,
f51: focal length of the fixed group of the fifth lens group f52: focal length of the movable group of the fifth lens group fw: focal length of the entire lens system at the wide angle end.

  The image pickup apparatus according to the present invention satisfies the conditional expressions (1) and (2), thereby improving the optical performance at the time of camera shake correction, optimizing the aberration correction, and shortening the total length of the entire zoom lens system. It is possible to reduce the size of the cylinder and prevent resolution degradation.

  In addition, in the imaging apparatus of the present invention, by appropriately setting the configuration of each lens of the zoom lens and each conditional expression, even when the movable group for correction is moved during camera shake correction, the deterioration of optical performance is suppressed. Therefore, it is possible to provide a small, high-quality, and high-magnification imaging apparatus.

Furthermore, the imaging apparatus of the present invention can be configured so that the three-piece cemented lens of the fifth lens group satisfies the following conditional expressions (5) and (6).
(5) fm <0
(6) νm <30
However,
fm: focal length of the intermediate lens in the three-piece cemented lens νm: the Abbe number of the intermediate lens in the three-piece cemented lens.

  By satisfying conditional expression (5) and conditional expression (6), the imaging apparatus of the present invention can satisfactorily correct various aberrations such as spherical aberration and coma aberration, suppress the occurrence of chromatic aberration, and improve image quality. Can be planned.

  FIG. 13 is a block diagram of a digital still camera according to an embodiment of the imaging apparatus of the present invention.

  The imaging device (digital still camera) 10 includes a lens unit 20 that optically acquires a subject image, and converts the optical image of the subject acquired by the lens unit 20 into an electrical image signal, and the converted electrical image signal And a camera body 30 having a function of controlling the lens unit 20 while performing various processes.

  The lens unit 20 includes a zoom lens 21 composed of optical elements such as a lens and a filter, a zoom drive unit 22 that moves the zooming group during zooming, a focus drive unit 23 that moves the focus group, and a shift lens group that is perpendicular to the optical axis. A shift lens driving unit 24 that shifts in a direction having components and an iris driving unit 25 that controls the degree of opening of the aperture stop are provided.

  As the zoom lens 21, any one of the zoom lenses 1 to 3 described above, or the zoom lens of the present invention such as Numerical Example 1 to Numerical Example 3 can be applied.

  The camera body 30 includes an image sensor 31 that converts an optical image formed by the zoom lens 21 into an electrical signal.

  For example, a CCD (Charge Coupled Device), a CMOS (Complementary Metal-Oxide Semiconductor), or the like can be applied to the imaging element 31. The electrical image signal output from the image pickup device 31 is subjected to various processes by the image processing circuit 32, and then data compressed by a predetermined method and temporarily stored in the image memory 33 as image data.

  A camera control CPU (Central Processing Unit) 34 has a function of controlling the entire camera body 30 and the lens unit 20, reads image data temporarily stored in the image memory 33, and displays a liquid crystal display (LCD) ) Displayed on 35 or stored in the external memory 36. The camera control CPU 34 reads image data stored in the external memory 36 and displays it on the liquid crystal display device 35.

  When the operation unit 40 such as a shutter release switch or a zooming switch is operated, a signal corresponding to the operation is input to the camera control CPU 34, and each unit is controlled based on the signal input by the camera control CPU 34. For example, when a shutter release switch is operated, a command signal is sent from the camera control CPU 34 to the timing control unit 37, a light beam from the zoom lens 21 is input to the image sensor 31, and the image sensor 31 is input by the timing control unit 37. The signal read timing is controlled.

  Signals related to the control of the zoom lens 21, for example, an AF (auto focus) signal, an AE (auto exposure) signal, a zooming signal, and the like are sent from the camera control CPU 34 to the lens control unit 38, and the zoom control unit 22 by the lens control unit 38. The focus driving unit 23 and the iris driving unit 25 are controlled, and the zoom lens 21 is changed to a predetermined state.

  The imaging apparatus 10 is provided with a camera shake sensor 39 that detects camera shake caused by vibrations of the image sensor 31. When the camera shake sensor 39 detects camera shake, the detection signal is input to the camera control CPU 34, and the camera A correction signal is generated by the control CPU 34, and the correction signal is sent to the shift lens driving unit 24 of the camera unit 20 via the lens control unit 38. When the correction signal is input to the shift lens driving unit 24, based on the input correction signal, the shift lens driving unit 24 causes the shift lens (the fifth lens described above) to cancel the displacement of the image on the image sensor 31 due to camera shake. The 5b lens group of the group 5L) is moved.

  In the above-described embodiment, an example in which the imaging apparatus is applied to a digital still camera has been described. However, the application range of the imaging apparatus is not limited to a digital still camera, and can also be applied as a digital video camera. .

  In addition, the shapes and numerical values of the respective parts shown in the above embodiments are merely examples of embodiments for carrying out the present invention, and the technical scope of the present invention is interpreted in a limited manner by these. There should be no such thing.

FIG. 2 to FIG. 13 show the best mode for carrying out the imaging apparatus and zoom lens of the present invention, and this figure shows the lens configuration of the first embodiment of the zoom lens of the present invention. . FIG. 3 and FIG. 4 show aberration diagrams of numerical examples in which specific numerical values are applied to the first embodiment, and this drawing shows spherical aberration, astigmatism, distortion aberration, and lateral aberration in the wide-angle end state. FIG. It is a figure which shows the spherical aberration, the astigmatism, the distortion aberration, and the lateral aberration in the intermediate focal length state. It is a figure which shows the spherical aberration, astigmatism, distortion aberration, and lateral aberration in a telephoto end state. It is a figure which shows the lens structure of 2nd Embodiment of this invention zoom lens. FIG. 7 and FIG. 8 show aberration diagrams of numerical examples in which specific numerical values are applied to the second embodiment, and this drawing shows spherical aberration, astigmatism, distortion aberration, and lateral aberration in the wide-angle end state. FIG. It is a figure which shows the spherical aberration, the astigmatism, the distortion aberration, and the lateral aberration in the intermediate focal length state. It is a figure which shows the spherical aberration, astigmatism, distortion aberration, and lateral aberration in a telephoto end state. It is a figure which shows the lens structure of 3rd Embodiment of this invention zoom lens. FIG. 11 and FIG. 12 show aberration diagrams of numerical examples in which specific numerical values are applied to the third embodiment, and this drawing shows spherical aberration, astigmatism, distortion aberration, and lateral aberration in the wide-angle end state. FIG. It is a figure which shows the spherical aberration, the astigmatism, the distortion aberration, and the lateral aberration in the intermediate focal length state. It is a figure which shows the spherical aberration, astigmatism, distortion aberration, and lateral aberration in a telephoto end state. It is a block diagram which shows one Embodiment of this invention imaging device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Zoom lens, 2 ... Zoom lens, 3 ... Zoom lens, L1 ... 1st lens group, L2 ... 2nd lens group, L3 ... 3rd lens group, L4 ... 4th lens group, L5 ... 5th lens group, L5-1 ... fixed group, L5-2 ... movable group, 10 ... imaging device, 21 ... zoom lens, 31 ... imaging element

Claims (30)

A first lens group having a positive refracting power and a fixed lens; a second lens group having a negative refracting power and movable at least in order to perform zooming; and a positive refracting power. A third lens group that is fixed, a fourth lens group that has positive refractive power and is movable in the direction of the optical axis in order to correct and focus the focal position by zooming, and positive refraction A zoom lens having a fifth lens group having power arranged in order from the object side to the image side,
The fifth lens group has a fixed group having a negative refractive power and a movable group having a positive refractive power and movable in a direction substantially orthogonal to the optical axis from the object side to the image side. Are arranged in order,
When the movable group of the fifth lens group is moved in a direction substantially orthogonal to the optical axis, an image formed on the image plane can be moved in a direction substantially orthogonal to the optical axis,
A zoom lens configured to satisfy the following conditional expression (1) and conditional expression (2):
(1) 0.6 <| f51 / f52 | <1.0
(2) 0.2 <fw / f52 <0.5
However,
f51: focal length of the fixed group of the fifth lens group f52: focal length of the movable group of the fifth lens group fw: focal length of the entire lens system at the wide angle end. The zoom lens according to claim 1, wherein the movable group of the fifth lens group is configured to satisfy the following conditional expression (3).
(3) 2.0 <ft / f52 <5.0
However,
ft: The focal length of the entire lens system at the telephoto end. The zoom lens according to claim 1, wherein the fifth lens group is configured to satisfy the following conditional expression (4).
(4) fi <f5
However,
fi: focal length of i-th lens group (i = 1 to 4)
f5: The focal length of the fifth lens group. The zoom lens according to claim 1, wherein at least one surface of the fifth lens group is formed as an aspheric surface. The fixed group of the fifth lens group includes an image from the object side of a first lens having a positive refractive power, a second lens having a negative refractive power, and a third lens having a negative refractive power. The zoom lens according to claim 1, comprising a cemented lens that is sequentially cemented to the side. The movable group of the fifth lens group is constituted by a cemented lens in which a fourth lens having a positive refractive power and a fifth lens having a negative refractive power are cemented in order from the object side to the image side. The zoom lens according to claim 1. An aperture stop is disposed at a position closer to the image side than the second lens group and closer to the object side than the fifth lens group,
At least one lens group among the lens groups arranged on the image side from the aperture stop has a three-piece cemented lens constituted by cementing three lenses,
The zoom lens according to claim 1, wherein the zoom lens is configured to satisfy the following conditional expressions (5) and (6).
(5) fm <0
(6) νm <30
However,
fm: focal length of the intermediate lens in the three-piece cemented lens νm: the Abbe number of the intermediate lens in the three-piece cemented lens. The zoom lens according to claim 7, wherein the three-piece cemented lens is configured to satisfy the following conditional expression (7).
(7) fs <0
However,
fs: The focal length of the three-piece cemented lens. The zoom lens according to claim 7, wherein the three-piece cemented lens is configured in the fifth lens group. A first lens having a positive refractive power, a second lens having a negative refractive power, and a third lens having a negative refractive power, which are arranged in order from the object side to the image side. The zoom lens according to claim 7, wherein the zoom lens is configured. The zoom lens according to claim 7, wherein at least one surface of the three-piece cemented lens is formed as an aspheric surface. The fifth lens group is configured to have a three-piece cemented lens having a negative refractive power and a lens group having a positive refractive power,
The zoom lens according to claim 1, wherein the zoom lens is configured to satisfy the following conditional expressions (5) and (6).
(5) fm <0
(6) νm <30
However,
fm: focal length of the intermediate lens in the three-piece cemented lens νm: the Abbe number of the intermediate lens in the three-piece cemented lens. A first lens having a positive refractive power, a second lens having a negative refractive power, and a third lens having a negative refractive power, which are arranged in order from the object side to the image side. The zoom lens according to claim 12, wherein the zoom lens is configured. The zoom lens according to claim 12, wherein at least one surface of the three-piece cemented lens is formed as an aspherical surface. An imaging apparatus comprising a zoom lens and an image sensor that converts an optical image formed by the zoom lens into an electrical signal,
The zoom lens is
A first lens group having a positive refracting power and a fixed lens; a second lens group having a negative refracting power and movable at least in order to perform zooming; and a positive refracting power. A third lens group that is fixed, a fourth lens group that has positive refractive power and is movable in the direction of the optical axis in order to correct and focus the focal position by zooming, and positive refraction A fifth lens group having power is arranged in order from the object side to the image side,
The fifth lens group has a fixed group having a negative refractive power and a movable group having a positive refractive power and movable in a direction substantially orthogonal to the optical axis from the object side to the image side. Are arranged in order,
When the movable group of the fifth lens group is moved in a direction substantially orthogonal to the optical axis, an image formed on the image plane can be moved in a direction substantially orthogonal to the optical axis,
An imaging apparatus configured to satisfy the following conditional expression (1) and conditional expression (2):
(1) 0.6 <| f51 / f52 | <1.0
(2) 0.2 <fw / f52 <0.5
However,
f51: focal length of the fixed group of the fifth lens group f52: focal length of the movable group of the fifth lens group fw: focal length of the entire lens system at the wide angle end. A first lens group having a positive refracting power and a fixed lens; a second lens group having a negative refracting power and movable at least in order to perform zooming; and a positive refracting power. A third lens group that is fixed, a fourth lens group that has positive refractive power and is movable in the direction of the optical axis in order to correct and focus the focal position by zooming, and positive refraction A zoom lens having a fifth lens group having power arranged in order from the object side to the image side,
The fifth lens group has a fixed group having a negative refractive power and a movable group having a positive refractive power and movable in a direction substantially orthogonal to the optical axis from the object side to the image side. Are arranged in order,
The fixed group of the fifth lens group includes an image from the object side of a first lens having a positive refractive power, a second lens having a negative refractive power, and a third lens having a negative refractive power. Consists of cemented lenses that are sequentially cemented to the side,
The movable group of the fifth lens group is configured by a cemented lens in which a fourth lens having a positive refractive power and a fifth lens having a negative refractive power are sequentially cemented from the object side to the image side,
When the movable group of the fifth lens group is moved in a direction substantially orthogonal to the optical axis, an image formed on the image plane can be moved in a direction substantially orthogonal to the optical axis,
A zoom lens configured to satisfy the following conditional expression (1) and conditional expression (2):
(1) 0.6 <| f51 / f52 | <1.0
(2) 0.2 <fw / f52 <0.5
However,
f51: focal length of the fixed group of the fifth lens group f52: focal length of the movable group of the fifth lens group fw: focal length of the entire lens system at the wide angle end. The zoom lens according to claim 16, wherein the movable group of the fifth lens group is configured to satisfy the following conditional expression (3).
(3) 2.0 <ft / f52 <5.0
However,
ft: The focal length of the entire lens system at the telephoto end. The zoom lens according to claim 16, wherein the fifth lens group is configured to satisfy the following conditional expression (4).
(4) fi <f5
However,
fi: focal length of i-th lens group (i = 1 to 4)
f5: The focal length of the fifth lens group. The zoom lens according to claim 16, wherein at least one surface of the fifth lens group is formed as an aspherical surface. An imaging apparatus comprising a zoom lens and an image sensor that converts an optical image formed by the zoom lens into an electrical signal,
The zoom lens is
A first lens group having a positive refracting power and a fixed lens; a second lens group having a negative refracting power and movable at least in order to perform zooming; and a positive refracting power. A third lens group that is fixed, a fourth lens group that has positive refractive power and is movable in the direction of the optical axis in order to correct and focus the focal position by zooming, and positive refraction A fifth lens group having power is arranged in order from the object side to the image side,
The fifth lens group has a fixed group having a negative refractive power and a movable group having a positive refractive power and movable in a direction substantially orthogonal to the optical axis from the object side to the image side. Are arranged in order,
The fixed group of the fifth lens group includes an image from the object side of a first lens having a positive refractive power, a second lens having a negative refractive power, and a third lens having a negative refractive power. Consists of cemented lenses that are sequentially cemented to the side,
The movable group of the fifth lens group is configured by a cemented lens in which a fourth lens having a positive refractive power and a fifth lens having a negative refractive power are sequentially cemented from the object side to the image side,
When the movable group of the fifth lens group is moved in a direction substantially orthogonal to the optical axis, an image formed on the image plane can be moved in a direction substantially orthogonal to the optical axis,
An imaging apparatus configured to satisfy the following conditional expression (1) and conditional expression (2):
(1) 0.6 <| f51 / f52 | <1.0
(2) 0.2 <fw / f52 <0.5
However,
f51: focal length of the fixed group of the fifth lens group f52: focal length of the movable group of the fifth lens group fw: focal length of the entire lens system at the wide angle end. A first lens group having a positive refracting power and a fixed lens; a second lens group having a negative refracting power and movable at least in order to perform zooming; and a positive refracting power. A third lens group that is fixed, a fourth lens group that has positive refractive power and is movable in the direction of the optical axis in order to correct and focus the focal position by zooming, and positive refraction A zoom lens having a fifth lens group having power arranged in order from the object side to the image side,
An aperture stop is disposed at a position closer to the image side than the second lens group and closer to the object side than the fifth lens group,
At least one lens group among the lens groups arranged on the image side from the aperture stop has a three-piece cemented lens constituted by cementing three lenses,
A zoom lens configured to satisfy the following conditional expressions (5) and (6):
(5) fm <0
(6) νm <30
However,
fm: focal length of the intermediate lens in the three-piece cemented lens νm: the Abbe number of the intermediate lens in the three-piece cemented lens. The zoom lens according to claim 21, wherein the three-piece cemented lens is configured to satisfy the following conditional expression (7).
(7) fs <0
However,
fs: The focal length of the three-piece cemented lens. The zoom lens according to claim 21, wherein the three-piece cemented lens is configured in the fifth lens group. A first lens having a positive refractive power, a second lens having a negative refractive power, and a third lens having a negative refractive power, which are arranged in order from the object side to the image side. The zoom lens according to claim 21, wherein the zoom lens is configured. The zoom lens according to claim 21, wherein at least one surface of the three-piece cemented lens is formed as an aspherical surface. An imaging apparatus comprising a zoom lens and an image sensor that converts an optical image formed by the zoom lens into an electrical signal,
The zoom lens is
A first lens group having a positive refracting power and a fixed lens; a second lens group having a negative refracting power and movable at least in order to perform zooming; and a positive refracting power. A third lens group that is fixed, a fourth lens group that has positive refractive power and is movable in the direction of the optical axis in order to correct and focus the focal position by zooming, and positive refraction A fifth lens group having power is arranged in order from the object side to the image side,
An aperture stop is disposed at a position closer to the image side than the second lens group and closer to the object side than the fifth lens group,
At least one lens group among the lens groups arranged on the image side from the aperture stop has a three-piece cemented lens constituted by cementing three lenses,
An image pickup apparatus configured to satisfy the following conditional expression (5) and conditional expression (6).
(5) fm <0
(6) νm <30
However,
fm: focal length of the intermediate lens in the three-piece cemented lens νm: the Abbe number of the intermediate lens in the three-piece cemented lens. A first lens group having a positive refracting power and a fixed lens; a second lens group having a negative refracting power and movable at least in order to perform zooming; and a positive refracting power. A third lens group that is fixed, a fourth lens group that has positive refractive power and is movable in the direction of the optical axis in order to correct and focus the focal position by zooming, and positive refraction A zoom lens having a fifth lens group having power arranged in order from the object side to the image side,
The fifth lens group is configured to have a three-piece cemented lens having a negative refractive power and a lens group having a positive refractive power,
A zoom lens configured to satisfy the following conditional expressions (5) and (6):
(5) fm <0
(6) νm <30
However,
fm: focal length of the intermediate lens in the three-piece cemented lens νm: the Abbe number of the intermediate lens in the three-piece cemented lens. A first lens having a positive refractive power, a second lens having a negative refractive power, and a third lens having a negative refractive power, which are arranged in order from the object side to the image side. The zoom lens according to claim 27, wherein the zoom lens is configured. The zoom lens according to claim 27, wherein at least one surface of the three-piece cemented lens is formed as an aspherical surface. An imaging apparatus comprising a zoom lens and an image sensor that converts an optical image formed by the zoom lens into an electrical signal,
The zoom lens is
A first lens group having a positive refracting power and a fixed lens; a second lens group having a negative refracting power and movable at least in order to perform zooming; and a positive refracting power. A third lens group that is fixed, a fourth lens group that has positive refractive power and is movable in the direction of the optical axis in order to correct and focus the focal position by zooming, and positive refraction A fifth lens group having power is arranged in order from the object side to the image side,
The fifth lens group is configured to have a three-piece cemented lens having a negative refractive power and a lens group having a positive refractive power,
An image pickup apparatus configured to satisfy the following conditional expression (5) and conditional expression (6).
(5) fm <0
(6) νm <30
However,
fm: focal length of the intermediate lens in the three-piece cemented lens νm: the Abbe number of the intermediate lens in the three-piece cemented lens.

Images