JP2017068115A - Fisheye zoom lens, optical device, method for manufacturing the fisheye zoom lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fisheye zoom lens that is further improved in optical performance, an optical device including the fisheye zoom lens, and a method for manufacturing the fisheye zoom lens.SOLUTION: A fisheye zoom lens ZL includes, in order from an object side, a first lens group G1 having negative refractive power and a second lens group G2 having positive refractive power. During zooming from a shortest focal length state to a longest focal length state, a distance between the first lens group G1 and the second lens group G2 changes. The second lens group G2 has: a second A lens group G2A disposed closer to the object side in a widest air interval; and a second B lens group G2B disposed closer to an image side in the air interval. The second A lens group G2A has at least one negative lens.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fish-eye zoom lens, an optical apparatus, and a method for manufacturing a fish-eye zoom lens.

  Conventionally, a fish-eye zoom lens capable of realizing a diagonal angle of view of 170 degrees or more with cameras having a plurality of screen sizes has been proposed (see, for example, Patent Document 1). However, Patent Document 1 has a problem that further improvement in optical performance is desired.

JP 2012-022109 A

  The fisheye zoom lens according to the present invention includes, in order from the object side, a first lens group having a negative refractive power and a second lens group having a positive refractive power, from the shortest focal length state to the longest focus. At the time of zooming to the distance state, the distance between the first lens group and the second lens group changes, and the second lens group has the air distance between the second A lens group arranged on the object side with the widest air distance. A second B lens group disposed on the image side, and the second A lens group includes at least one negative lens.

  The fish-eye zoom lens according to the present invention includes, in order from the object side, a first lens group having a negative refractive power and a second lens group having a positive refractive power, from the shortest focal length state. At the time of zooming to the longest focal length state, the distance between the first lens group and the second lens group changes, and the second lens group has a second A lens group, an aperture stop, and a second B lens from the object side. The second A lens group has at least one negative lens.

  The method for manufacturing a fish-eye zoom lens according to the present invention includes, in order from the object side, a fish-eye zoom lens having a first lens group having a negative refractive power and a second lens group having a positive refractive power. In which the distance between the first lens group and the second lens group is changed at the time of zooming from the shortest focal length state to the longest focal length state. A second A lens group disposed on the object side of the air interval and a second B lens group disposed on the image side of the air interval are disposed, and at least one negative lens is disposed in the second A lens group. And

It is sectional drawing which shows the lens structure of the fisheye zoom lens which concerns on 1st Example. FIG. 5A is a diagram illustrating various aberrations in the shortest focal length state of the fish-eye zoom lens according to the first example, where (a) shows an infinite focus state, and (b) shows a short focus state. FIG. 4A is a diagram illustrating various aberrations in the longest focal length state of the fish-eye zoom lens according to the first example, where (a) shows an infinite focus state and (b) shows a short distance focus state. It is sectional drawing which shows the lens structure of the fisheye zoom lens which concerns on 2nd Example. FIG. 5A is a diagram illustrating various aberrations in the shortest focal length state of the fish-eye zoom lens according to Example 2, where (a) shows an infinite focus state and (b) shows a short focus state. FIG. 4A is a diagram illustrating various aberrations of the fish-eye zoom lens according to the second embodiment in the longest focal length state, where FIG. It is sectional drawing which shows the lens structure of the fisheye zoom lens which concerns on 3rd Example. FIG. 6A is a diagram illustrating various aberrations in the shortest focal length state of the fish-eye zoom lens according to Example 3, where (a) illustrates an infinite focus state, and (b) illustrates a close focus state. FIG. 6A is a diagram illustrating various aberrations of the fish-eye zoom lens according to the third example in the longest focal length state, in which (a) shows an infinite focus state, and (b) shows a short focus state. It is sectional drawing which shows the lens structure of the fisheye zoom lens which concerns on 4th Example. FIG. 6A is a diagram illustrating various aberrations in the shortest focal length state of the fish-eye zoom lens according to Example 4, where (a) illustrates an infinite focus state and (b) illustrates a close focus state. FIG. 9A is a diagram illustrating various aberrations of the longest focal length state of the fish-eye zoom lens according to the fourth example, in which (a) shows an infinite focus state, and (b) shows a short focus state. It is sectional drawing which shows the lens structure of the fisheye zoom lens which concerns on 5th Example. FIG. 6A is a diagram illustrating various aberrations in the shortest focal length state of the fish-eye zoom lens according to Example 5, where (a) shows an infinite focus state and (b) shows a short focus state. FIG. 6A is a diagram illustrating various aberrations in the longest focal length state of the fish-eye zoom lens according to Example 5, where (a) shows an infinite focus state, and (b) shows a short focus state. It is sectional drawing which shows the lens structure of the fisheye zoom lens which concerns on 6th Example. FIG. 6A is a diagram illustrating various aberrations in the shortest focal length state of the fish-eye zoom lens according to Example 6, where (a) shows an infinite focus state, and (b) shows a short focus state. FIG. 9A is a diagram illustrating various aberrations of the fish-eye zoom lens according to the sixth example in the longest focal length state, where FIG. It is sectional drawing which shows the lens structure of the fisheye zoom lens which concerns on 7th Example. FIG. 9A is a diagram illustrating various aberrations in the shortest focal length state of the fish-eye zoom lens according to Example 7, where (a) illustrates an infinite focus state, and (b) illustrates a close focus state. FIG. 9A is a diagram illustrating various aberrations in the longest focal length state of the fish-eye zoom lens according to Example 7, wherein (a) illustrates an infinite focus state, and (b) illustrates a close focus state. It is sectional drawing which shows the lens structure of the fisheye zoom lens which concerns on 8th Example. FIG. 9A is a diagram illustrating various aberrations in the shortest focal length state of the fish-eye zoom lens according to Example 8, where (a) illustrates an infinite focus state, and (b) illustrates a close focus state. FIG. 9A is a diagram illustrating various aberrations of the fish-eye zoom lens according to Example 8 in the longest focal length state, where FIG. 9A illustrates an infinite focus state, and FIG. It is sectional drawing of the camera carrying the said fisheye zoom lens. It is a flowchart for demonstrating the manufacturing method of the said fisheye zoom lens.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the fish-eye zoom lens ZL according to this embodiment includes, in order from the object side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, It is comprised. In the fish-eye zoom lens ZL, the distance between the first lens group G1 and the second lens group G2 changes when zooming from the shortest focal length state to the longest focal length state. With this configuration, it is possible to obtain good optical performance while obtaining a predetermined zoom ratio while ensuring back focus in the shortest focal length state.

  In the fish-eye zoom lens ZL according to the present embodiment, the second lens group G2 includes a second A lens group G2A disposed on the object side with the widest air interval and a second B disposed on the image side with the air interval. And a lens group GB. With this configuration, various aberrations such as spherical aberration, coma aberration, and field curvature can be favorably corrected.

  In the fisheye zoom lens ZL according to this embodiment, the aperture stop S is disposed in the second lens group G2. In other words, the second lens group G2 includes, in order from the object side, the second A lens group G2A, the aperture stop S, and the second B lens group G2B. With this configuration, various aberrations such as spherical aberration, coma aberration, and field curvature can be favorably corrected.

  The second A lens group G2A has at least one negative lens. With this configuration, it is possible to satisfactorily correct the spherical aberration and the curvature variation of the field curvature from the shortest focal length state to the longest focal length state.

  In the fish-eye zoom lens ZL according to the present embodiment, it is desirable that the aperture stop S is configured to move integrally with the second lens group G2 at the time of zooming. With this configuration, various aberrations such as spherical aberration, coma aberration, and field curvature can be favorably corrected.

  In addition, it is desirable that the fish-eye zoom lens ZL according to the present embodiment satisfies the following conditional expression (1).

0.50 <Yw / {2 × fw × sin (θw / 2)} <2.50 (1)
However,
Yw: Maximum image height in the shortest focal length state fw: Total system focal length in the shortest focal length state θw: Maximum shooting half angle of view in the shortest focal length state

  Conditional expression (1) defines the ratio of the image size to the focal length and the angle of view in the shortest focal length state. By satisfying the conditional expression (1), it is possible to provide an equisolid angle projection type fisheye zoom lens. If the lower limit value of the conditional expression (1) is not reached, distortion on the equal solid angle projection method is generated on the minus side, which is not preferable. In order to secure the effect of the conditional expression (1), it is desirable to set the lower limit value of the conditional expression (1) to 0.80. In order to further secure the effect of the conditional expression (1), it is desirable to set the lower limit value of the conditional expression (1) to 0.90. In order to further secure the effect of the conditional expression (1), it is desirable to set the lower limit value of the conditional expression (1) to 0.95. Moreover, if the upper limit value of conditional expression (1) is exceeded, distortion aberration with respect to the equisolid angle projection method occurs on the plus side, which is not preferable. In order to secure the effect of the conditional expression (1), it is desirable that the upper limit value of the conditional expression (1) is 2.20. In order to further secure the effect of the conditional expression (1), it is desirable to set the upper limit value of the conditional expression (1) to 2.00. In order to further secure the effect of the conditional expression (1), it is desirable to set the upper limit value of the conditional expression (1) to 1.50. In order to further secure the effect of the conditional expression (1), it is desirable that the upper limit value of the conditional expression (1) is 1.20.

  Moreover, it is desirable that the fish-eye zoom lens ZL according to the present embodiment satisfies the following conditional expression (2).

0.50 <Yt / {2 × ft × sin (θt / 2)} <2.50 (2)
However,
Yt: Maximum image height in the longest focal length state ft: Focal length of the entire system in the longest focal length state θt: Maximum shooting half angle of view in the longest focal length state

  Conditional expression (2) defines the ratio of the image size to the focal length and the angle of view in the longest focal length state. By satisfying the conditional expression (2), it is possible to provide a fisheye zoom lens of an equisolid angle projection method. If the lower limit of conditional expression (2) is not reached, distortion with respect to the equisolid angle projection method occurs on the negative side, which is not preferable. In order to secure the effect of the conditional expression (2), it is desirable to set the lower limit value of the conditional expression (2) to 0.80. In order to further secure the effect of the conditional expression (2), it is desirable to set the lower limit value of the conditional expression (2) to 0.90. In order to further secure the effect of the conditional expression (2), it is desirable to set the lower limit value of the conditional expression (2) to 0.95. On the other hand, if the upper limit value of conditional expression (2) is exceeded, distortion with respect to the equisolid angle projection method is generated on the plus side, which is not preferable. In order to secure the effect of the conditional expression (2), it is desirable that the upper limit value of the conditional expression (2) is 2.20. In order to further secure the effect of the conditional expression (2), it is desirable to set the upper limit value of the conditional expression (2) to 2.00. In order to further secure the effect of the conditional expression (2), it is desirable to set the upper limit value of the conditional expression (2) to 1.50. In order to further secure the effect of the conditional expression (2), it is desirable to set the upper limit value of the conditional expression (2) to 1.20.

  In addition, it is desirable that the fish-eye zoom lens ZL according to the present embodiment has a maximum image height having different sizes in the shortest focal length state and the longest focal length state. With this configuration, so-called circular fish-eye and diagonal fish-eye can be photographed in various format sizes.

  Moreover, it is desirable that the fish-eye zoom lens ZL according to the present embodiment satisfies the following conditional expression (3).

θw ≧ 50 [°] (3)
However,
θw: Maximum shooting half angle of view in the shortest focal length state

  Satisfying the conditional expression (3) enables photographing of so-called circular fish eyes and diagonal fish eyes in various format sizes. In order to secure the effect of the conditional expression (3), it is desirable that the lower limit value of the conditional expression (3) is 60 [°]. In order to further secure the effect of the conditional expression (3), it is desirable to set the lower limit value of the conditional expression (3) to 70 [°]. In order to further secure the effect of the conditional expression (3), it is desirable to set the lower limit value of the conditional expression (3) to 80 [°]. In order to further secure the effect of the conditional expression (3), it is desirable to set the lower limit value of the conditional expression (3) to 85 [°].

  Moreover, it is desirable that the fish-eye zoom lens ZL according to the present embodiment satisfies the following conditional expression (4).

θt ≧ 50 [°] (4)
However,
θt: Maximum shooting half angle of view at maximum focal length

  Satisfying the conditional expression (4) enables photographing of so-called circular fish eyes and diagonal fish eyes in various format sizes. In order to secure the effect of the conditional expression (4), it is desirable to set the lower limit value of the conditional expression (4) to 60 [°]. In order to further ensure the effect of the conditional expression (4), it is desirable to set the lower limit value of the conditional expression (4) to 70 [°]. In order to further secure the effect of the conditional expression (4), it is desirable to set the lower limit value of the conditional expression (4) to 80 [°]. In order to further secure the effect of the conditional expression (4), it is desirable to set the lower limit value of the conditional expression (4) to 85 [°].

  In the fish-eye zoom lens ZL according to this embodiment, a part of the second lens group G2 moves on the optical axis as the focusing lens group G2F during focusing. With such a configuration, it is possible to obtain a good optical performance while obtaining a predetermined zoom ratio while ensuring a back focus in the shortest focal length state.

  In the fish-eye zoom lens ZL according to the present embodiment, at least a part of the second A lens group GA on the image side or a part of the second B lens group G2B on the object side is the focusing lens group G2F. It is desirable that the focusing lens group G2F is configured to move on the optical axis during focusing. By configuring in this way, it is possible to obtain a good optical performance when focusing on a short-distance Buddhist script while being a small focusing lens group G2F.

  Further, the fish-eye zoom lens ZL according to the present embodiment has at least a part of the second A lens group G2A on the image side as the focusing lens group G2F from the object side to the image side when focusing from infinity to a short distance object. It is desirable to be configured to move. By configuring in this way, it is possible to obtain a good optical performance at the time of focusing while being a small focusing group.

  Alternatively, the fish-eye zoom lens ZL according to the present embodiment moves part of the object side of the second B lens group G2B from the image side to the object side as the focusing lens group G2F when focusing from infinity to a close object. It is desirable to be configured. By configuring in this way, it is possible to obtain a good optical performance at the time of focusing while being a small focusing group.

  In the fish-eye zoom lens ZL according to the present embodiment, it is desirable that the second A lens group G2A has at least one positive lens and satisfies the following conditional expression (5).

0.01 <nd2an2-nd2ap2 <0.50 (5)
However,
nd2ap2: average value of refractive index with respect to d-line of medium of positive lens included in second A lens group G2A nd2an2: average value of refractive index with respect to d-line of medium of negative lens included in second A lens group G2A

  Conditional expression (5) defines the difference in refractive index with respect to the d-line of the medium of the positive lens and negative lens of the second A lens group G2A. If the lower limit value of conditional expression (5) is not reached, correction of curvature of field in the 2A lens group G2A is insufficient, and correction of curvature of field at the time of focusing at the longest focal length state becomes difficult. Absent. In order to secure the effect of the conditional expression (5), it is desirable to set the lower limit value of the conditional expression (5) to 0.02. In order to further secure the effect of the conditional expression (5), it is desirable to set the lower limit value of the conditional expression (5) to 0.05. If the upper limit of conditional expression (5) is exceeded, the correction of the field curvature in the second lens group G2A becomes excessive, and it becomes difficult to correct the field curvature at the time of infinite focusing at the longest focal length state. Therefore, it is not preferable. In order to secure the effect of the conditional expression (5), it is desirable to set the upper limit value of the conditional expression (5) to 0.30. In order to further secure the effect of the conditional expression (5), it is desirable to set the upper limit value of the conditional expression (5) to 0.25.

  In the fisheye zoom lens ZL according to this embodiment, it is desirable that the second A lens group G2A has at least one positive lens and satisfies the following conditional expression (6).

−10.0 <νd2ap2-νd2an2 <30.0 (6)
However,
νd2ap2: average value of Abbe number with respect to d-line of medium of positive lens of second A lens group G2A νd2an2: average value of Abbe number with respect to d-line of medium of negative lens of second A lens group G2A

  Conditional expression (6) defines the Abbe number difference with respect to the d-line of the medium of the positive lens and negative lens of the second A lens group G2A. If the lower limit value of conditional expression (6) is not reached, correction of axial chromatic aberration in the second lens group G2A is insufficient, and correction of axial chromatic aberration during focusing at the longest focal length state becomes difficult, which is not preferable. In order to secure the effect of the conditional expression (6), it is desirable to set the lower limit value of the conditional expression (6) to −7.0. In order to further secure the effect of the conditional expression (6), it is desirable to set the lower limit value of the conditional expression (6) to −4.5. If the upper limit value of conditional expression (6) is exceeded, the correction of axial chromatic aberration in the second lens group G2A becomes excessive, and it becomes difficult to correct axial chromatic aberration during infinite focusing at the longest focal length state. Absent. In order to secure the effect of the conditional expression (6), it is desirable that the upper limit value of the conditional expression (6) is 20.0. In order to further secure the effect of the conditional expression (6), it is desirable to set the upper limit of the conditional expression (6) to 18.0. In order to further secure the effect of the conditional expression (6), it is desirable that the upper limit value of the conditional expression (6) is 17.5.

  Moreover, it is desirable that the fish-eye zoom lens ZL according to the present embodiment satisfies the following conditional expression (7).

1.80 <f2 / (− f1) <3.20 (7)
However,
f1: Focal length of the first lens group G1 f2: Focal length of the second lens group G2

  Conditional expression (7) defines the ratio of the focal lengths of the second lens group G2 and the first lens group G1. If the lower limit of conditional expression (7) is not reached, the focal length of the second lens group G2 becomes small, and it becomes difficult to correct spherical aberration in the longest focal length state, which is not preferable. In order to secure the effect of the conditional expression (7), it is desirable to set the lower limit value of the conditional expression (7) to 2.00. In order to further secure the effect of the conditional expression (7), it is desirable to set the lower limit value of the conditional expression (7) to 2.40. If the upper limit of conditional expression (7) is exceeded, the focal length of the second lens group G2 becomes large, and it becomes difficult to correct field curvature aberration in the longest focal length state. In order to secure the effect of the conditional expression (7), it is desirable that the upper limit value of the conditional expression (7) is 2.80. In order to further secure the effect of the conditional expression (7), it is desirable to set the upper limit value of the conditional expression (7) to 2.60.

  Moreover, it is desirable that the fish-eye zoom lens ZL according to the present embodiment satisfies the following conditional expression (8).

1.00 <| f2A2 | / (− f1) <6.00 (8)
However,
f2A2: focal length of the second A lens group G2A f1: focal length of the first lens group G1

  Conditional expression (8) defines the ratio of the focal lengths of the second A lens group G2A and the first lens group G1. If the lower limit of conditional expression (8) is not reached, the focal length of the second A lens group G2A becomes small, and it becomes difficult to correct spherical aberration during focusing at the longest focal length state, which is not preferable. In order to secure the effect of the conditional expression (8), it is desirable that the lower limit value of the conditional expression (8) is 1.30. In order to further secure the effect of the conditional expression (8), it is desirable to set the lower limit value of the conditional expression (8) to 1.65. If the upper limit of conditional expression (8) is exceeded, the focal length of the second A lens group G2A increases, and in order to secure the movement distance of the focusing lens group for focusing, the first lens group G1 The focal length must be reduced. As a result, it is difficult to correct astigmatism in the longest focal length state. In order to secure the effect of the conditional expression (8), it is desirable to set the upper limit value of the conditional expression (8) to 5.50. In order to further secure the effect of the conditional expression (8), it is desirable to set the upper limit of the conditional expression (8) to 4.95.

  Moreover, it is desirable that the fish-eye zoom lens ZL according to the present embodiment satisfies the following conditional expression (9).

1.00 <| f2B2 | / (− f1) <7.50 (9)
However,
f2B2: focal length of the second B lens group G2B f1: focal length of the first lens group G1

  Conditional expression (9) defines the ratio of the focal lengths of the second B lens group G2B and the first lens group G1. If the lower limit of conditional expression (9) is not reached, the focal length of the second B lens group G2B becomes small, and it becomes difficult to correct field curvature aberration in the longest focal length state, which is not preferable. In order to secure the effect of the conditional expression (9), it is desirable to set the lower limit value of the conditional expression (9) to 1.50. In order to further secure the effect of the conditional expression (9), it is desirable to set the lower limit value of the conditional expression (9) to 2.00. If the upper limit of conditional expression (9) is exceeded, the focal length of the second B lens group G2B increases, and in order to ensure the movement distance of the focusing lens group for focusing, the first lens group G1 The focal length must be reduced. As a result, it is difficult to correct astigmatism in the longest focal length state. In order to secure the effect of the conditional expression (9), it is desirable to set the upper limit value of the conditional expression (9) to 6.50. In order to further secure the effect of the conditional expression (9), it is desirable to set the upper limit value of the conditional expression (9) to 5.50.

  Moreover, it is desirable that the fish-eye zoom lens ZL according to the present embodiment satisfies the following conditional expression (10).

1.00 <| f2F | / (− f1) <6.00 (10)
However,
f2F: focal length of the focusing lens group G2F f1: focal length of the first lens group G1

  Conditional expression (10) defines the ratio of the focal lengths of the focusing lens group G2F and the first lens group G1. Within the range of the conditional expression (10), it is possible to reduce aberration fluctuations during focusing such as spherical aberration, coma aberration, and field curvature. In order to secure the effect of the conditional expression (10), it is desirable to set the lower limit value of the conditional expression (10) to 1.40. In order to further secure the effect of the conditional expression (10), it is desirable to set the lower limit value of the conditional expression (10) to 1.70. In order to ensure the effect of the conditional expression (10), it is desirable to set the upper limit value of the conditional expression (10) to 5.50. In order to further secure the effect of the conditional expression (10), it is desirable to set the upper limit value of the conditional expression (10) to 5.00. In order to further secure the effect of the conditional expression (10), it is desirable that the upper limit value of the conditional expression (10) is 4.50.

  Moreover, it is desirable that the fish-eye zoom lens ZL according to the present embodiment satisfies the following conditional expression (11).

0.80 <(r1 + r2) / (r1-r2) <2.30 (11)
However,
r1: radius of curvature of the object side lens surface of the lens closest to the object side of the first lens group G1 r2: radius of curvature of the lens surface of the image side of the lens closest to the object side of the first lens group G1

  Conditional expression (11) defines the shape factor of the lens closest to the object side in the first lens group G1. If the lower limit of conditional expression (11) is not reached, it will be difficult to correct astigmatism in the longest focal length state, which is not preferable. In order to secure the effect of the conditional expression (11), it is desirable that the lower limit value of the conditional expression (11) is 1.10. In order to further secure the effect of the conditional expression (11), it is desirable to set the lower limit value of the conditional expression (11) to 1.30. On the other hand, if the upper limit of conditional expression (11) is exceeded, the degree of difficulty in lens processing increases, and astigmatism in the longest focal length state during manufacturing increases, which is not preferable. In order to secure the effect of the conditional expression (11), it is desirable to set the upper limit value of the conditional expression (11) to 2.00. In order to further secure the effect of the conditional expression (11), it is desirable to set the upper limit value of the conditional expression (11) to 1.80.

  Moreover, it is desirable that the fish-eye zoom lens ZL according to the present embodiment satisfies the following conditional expression (12).

3.5 <Bfw / fw <8.0 (12)
However,
Bfw: Back focus in the shortest focal length state fw: Total system focal length in the shortest focal length state

  Conditional expression (12) defines the ratio between the back focus and the focal length in the shortest focal length state. If the lower limit of conditional expression (12) is not reached, the back focus becomes small and interferes with the mirror of the body, which is not preferable. In order to secure the effect of the conditional expression (12), it is desirable that the lower limit value of the conditional expression (12) is 4.3. In order to further secure the effect of the conditional expression (12), it is desirable that the lower limit value of the conditional expression (12) is 4.5. If the upper limit of conditional expression (12) is exceeded, the focal length of the first lens group G1 must be reduced in order to ensure a large back focus, and as a result, the astigmatism in the longest focal length state. Aberration correction is difficult, which is not preferable. In order to secure the effect of the conditional expression (12), it is desirable that the upper limit value of the conditional expression (12) is 5.2. In order to further secure the effect of the conditional expression (12), it is desirable to set the upper limit of the conditional expression (12) to 5.0.

  In the fish-eye zoom lens ZL according to this embodiment, it is desirable that the optical axis is linear over the entire system. With this configuration, the lens holding mechanism can be simplified, and coma during manufacturing can be corrected well.

  In addition, it is desirable that the fish-eye zoom lens ZL according to the present embodiment is configured only by a refractive system. Such a configuration makes it less susceptible to the shape error of the lens surface and can satisfactorily correct spherical aberration during manufacturing.

  In addition, it is desirable that the fisheye zoom lens ZL according to the present embodiment satisfies the following conditional expression (13).

12.0 <TLw / fw <18.0 (13)
However,
TLw: total optical length in the shortest focal length state fw: focal length of the entire system in the shortest focal length state

  Conditional expression (13) defines the ratio between the total optical length and the focal length in the shortest focal length state. If the lower limit of conditional expression (13) is not reached, it is necessary to reduce the number of lenses in the first lens group G1 in order to shorten the total optical length. As a result, the focal length of each lens is reduced, and the field curvature aberration is reduced. This is not preferable because correction becomes difficult. In order to secure the effect of the conditional expression (13), it is desirable to set the lower limit value of the conditional expression (13) to 14.0. In order to further secure the effect of the conditional expression (13), it is desirable to set the lower limit of the conditional expression (13) to 14.5. If the upper limit of conditional expression (13) is exceeded, the focal length of the first lens group G1 must be reduced in order to ensure a large overall length, and as a result, astigmatism in the longest focal length state. This is not preferable because it is difficult to correct. In order to secure the effect of the conditional expression (13), it is desirable to set the upper limit value of the conditional expression (13) to 17.0. In order to further secure the effect of the conditional expression (13), it is desirable to set the upper limit of the conditional expression (13) to 16.5.

  Note that the conditions and configurations described above each exhibit the above-described effects, and are not limited to satisfying all the conditions and configurations. The above-described effects can be obtained even if the combination of the above conditions or configurations is satisfied.

  Next, a camera that is an optical device including the fish-eye zoom lens ZL according to the present embodiment will be described with reference to FIG. This camera 1 is a so-called mirrorless camera with interchangeable lenses provided with a fish-eye zoom lens ZL according to the present embodiment as a photographing lens 2. In the camera 1, light from an object (subject) (not shown) is collected by the photographing lens 2 and is on the imaging surface of the imaging unit 3 via an OLPF (Optical low pass filter) (not shown). A subject image is formed on the screen. Then, the subject image is photoelectrically converted by the photoelectric conversion element provided in the imaging unit 3 to generate an image of the subject. This image is displayed on an EVF (Electronic view finder) 4 provided in the camera 1. Thus, the photographer can observe the subject via the EVF 4.

  Further, when a release button (not shown) is pressed by the photographer, an image photoelectrically converted by the imaging unit 3 is stored in a memory (not shown). In this way, the photographer can shoot the subject with the camera 1. In this embodiment, an example of a mirrorless camera has been described. However, a fish-eye zoom lens ZL according to this embodiment is used in a single-lens reflex camera that has a quick return mirror in the camera body and observes a subject with a finder optical system. Even when the camera is mounted, the same effect as the camera 1 can be obtained.

  The contents described below can be appropriately adopted as long as the optical performance is not impaired.

  In the present embodiment, the fish-eye zoom lens ZL having a two-group or three-group configuration is shown, but the above-described configuration conditions and the like can also be applied to other group configurations such as the 4-group and 5-group. Further, a configuration in which a lens or a lens group is added closest to the object side, or a configuration in which a lens or a lens group is added closest to the image plane side may be used. Specifically, a configuration in which a lens group whose position relative to the image plane is fixed at the time of zooming or focusing is added to the most image plane side. The lens group refers to a portion having at least one lens separated by an air interval that changes at the time of zooming or focusing. Further, in the fish-eye zoom lens ZL of the present embodiment, the first lens group G1 to the second lens group G2 (or the third lens group G3) are respectively light so that the air space between the groups changes at the time of zooming. Move along the axis. The lens component refers to a single lens or a cemented lens in which a plurality of lenses are cemented.

  Alternatively, a single lens group, a plurality of lens groups, or a partial lens group may be moved in the optical axis direction to be a focusing lens group that performs focusing from an object at infinity to a near object. In this case, the focusing lens group can be applied to autofocus, and is also suitable for driving a motor for autofocus (such as an ultrasonic motor). In particular, it is preferable that at least a part of the second lens group G2 is a focusing lens group, and the other lenses are fixed in position relative to the image plane during focusing. Considering the load applied to the motor, it is preferable that the focusing lens group is composed of a single lens.

  In addition, the lens group or partial lens group is moved so as to have a displacement component perpendicular to the optical axis, or rotated (swinged) in the in-plane direction including the optical axis to correct image blur caused by camera shake. An anti-vibration lens group may be used. In particular, as described above, it is preferable that at least a part of the second lens group G2 is a vibration-proof lens group.

  Further, the lens surface may be formed as a spherical surface, a flat surface, or an aspheric surface. When the lens surface is a spherical surface or a flat surface, lens processing and assembly adjustment are facilitated, and optical performance deterioration due to errors in processing and assembly adjustment can be prevented. Further, even when the image plane is deviated, it is preferable because there is little deterioration in drawing performance. When the lens surface is an aspheric surface, the aspheric surface is an aspheric surface by grinding, a glass mold aspheric surface made of glass with an aspheric shape, or a composite aspheric surface made of resin with an aspheric shape on the glass surface. Any aspherical surface may be used. The lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

  The aperture stop S is preferably disposed in the vicinity of or in the second lens group G2. However, the role of the aperture stop may be substituted by a lens frame without providing a member as an aperture stop.

  Further, each lens surface may be provided with an antireflection film having high transmittance in a wide wavelength region in order to reduce flare and ghost and achieve high optical performance with high contrast.

  Further, the fisheye zoom lens ZL of this embodiment has a zoom ratio of about 1.5 to 5 times.

  Hereinafter, an outline of a method for manufacturing the fish-eye zoom lens ZL according to the present embodiment will be described with reference to FIG. First, each lens is arranged to prepare a first lens group G1 and a second lens group G2 (step S100). At the time of zooming from the shortest focal length state to the longest focal length state, the first lens group G1 and the second lens group G2 are prepared. The two lens groups G2 are arranged so that the distance between them changes (step S200). Further, as the second lens group G2, a second A lens group G2B disposed on the object side with the widest air interval and a second B lens group G2B disposed on the image side with the air interval are disposed (step S300). In addition, at least one negative lens is disposed in the second A lens group G2A (step S400).

  Specifically, in the present embodiment, for example, as shown in FIG. 1, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side, and the object-side lens surface are formed in an aspheric shape. A negative meniscus negative lens L12 having a convex surface facing the side, a biconcave negative lens L13, a positive meniscus lens L14 having a convex surface facing the object side, and a biconcave negative lens L15 are arranged to form the first lens group G1. A second meniscus lens having a positive meniscus lens L21 having a convex surface facing the object side, a negative meniscus lens L22 having a concave surface facing the object side, and a cemented lens in which a biconcave negative lens L23 and a biconvex positive lens L24 are cemented. A cemented lens obtained by cementing the group G2A, a negative meniscus lens L25 having a concave surface facing the object side, and a positive meniscus lens L26 having a concave surface facing the object side, and a biconvex positive lens L2 And a negative meniscus lens L28 having a concave surface facing the object side, a cemented lens having a biconcave negative lens L29 and a positive meniscus lens L210 having a convex surface facing the object side, and a convex surface facing the object side. A cemented lens in which the negative meniscus lens L211 and the biconvex positive lens L212 are cemented, and a second B lens group G2B in which the biconvex positive lens L213 is disposed are arranged as a second lens group G2. At this time, the second A lens group G2A is set as a focusing lens group G2F. An aperture stop S is disposed between the second A lens group G2A and the second B lens group G2B. The fish lens zoom lens ZL is manufactured by arranging the lens groups thus prepared in the above-described procedure.

  With the configuration as described above, it is possible to provide a fish-eye zoom lens ZL with further improved optical performance, an optical apparatus having the fish-eye zoom lens ZL, and a method for manufacturing the fish-eye zoom lens ZL.

  Hereinafter, each example of the present application will be described with reference to the drawings. 1, 4, 7, 10, 13, 16, 19, and 22 show the configuration and refractive power distribution of the fish-eye zoom lens ZL (ZL1 to ZL8) according to each embodiment. It is sectional drawing. In addition, below the fisheye zoom lenses ZL1 to ZL68 cross-sectional views, the lens groups G1 to G2 (or G3) for zooming from the shortest focal length state (W) to the longest focal length state (T) are shown. The direction of movement along the optical axis is indicated by arrows.

In each embodiment, the height of the aspheric surface in the direction perpendicular to the optical axis is y, and the distance (sag amount) along the optical axis from the tangential plane of the apex of each aspheric surface to each aspheric surface at height y. Is S (y), r is the radius of curvature of the reference sphere (paraxial radius of curvature), K is the conic constant, and An is the nth-order aspherical coefficient, it is expressed by the following equation (a). . In the following examples, “E−n” indicates “× 10 ⁻ⁿ ”.

S (y) = (y ² / r) / {1+ (1−K × y ² / r ² ) ^1/2 }
+ A4 × y ⁴ + A6 × y ⁶ + A8 × y ⁸ + A10 × y ¹⁰ (a)

  In each embodiment, the secondary aspheric coefficient A2 is zero. In the table of each example, an aspherical surface is marked with * on the right side of the surface number.

[First embodiment]
FIG. 1 is a diagram illustrating a configuration of a fish-eye zoom lens ZL1 according to the first embodiment. The fisheye zoom lens ZL1 shown in FIG. 1 includes, in order from the object side, a first lens group G1 having a negative refractive power and a second lens group G2 having a positive refractive power. The second lens group G2 includes, in order from the object side, a second A lens group G2A having a positive refractive power and a second B lens group G2B having a positive refractive power.

  In the fish-eye zoom lens ZL1, the first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface directed toward the object side, and a lens surface on the object side formed in an aspherical shape. Negative lens L12 having a negative meniscus shape facing the lens, a biconcave negative lens L13, a positive meniscus lens L14 having a convex surface facing the object side, and a biconcave negative lens L15. The second A lens group G2A constituting the second lens group G2 includes, in order from the object side, a positive meniscus lens L21 having a convex surface facing the object side, a negative meniscus lens L22 having a concave surface facing the object side, and a biconcave lens. It is composed of a cemented lens in which a negative lens L23 and a biconvex positive lens L24 are cemented. Further, the second B lens group G2B constituting the second lens group G2 is formed by joining, in order from the object side, a negative meniscus lens L25 having a concave surface facing the object side and a positive meniscus lens L26 having a concave surface facing the object side. A cemented lens in which a biconvex positive lens L27 and a negative meniscus lens L28 having a concave surface facing the object side are cemented, a cemented lens in which a biconcave negative lens L29 and a positive meniscus lens L210 having a convex surface facing the object side are cemented, The lens includes a cemented lens in which a negative meniscus lens L211 having a convex surface on the object side and a biconvex positive lens L212 are cemented, and a biconvex positive lens L213. The aperture stop S is disposed between the biconvex positive lens L24 and the negative meniscus lens L25 in the second lens group G2.

  The fish-eye zoom lens ZL1 has each lens group on the optical axis so that the distance between the first lens group G1 and the second lens group G2 is reduced upon zooming from the shortest focal length state to the longest focal length state. Configured to move along. The aperture stop S moves integrally with the second lens group G2.

  In the fish-eye zoom lens ZL1, the second lens group G2A is used as a focusing lens group G2F, and focusing from an infinite distance to a close object is performed by moving the focusing lens group G2F to the image side. It is configured. The aperture stop S is fixed with respect to the image plane I at the time of focusing.

  Table 1 below lists values of specifications of the fisheye zoom lens ZL1. In Table 1, f is the focal length of the entire system, FNO is the F number, θ is the half field angle (unit is [°]), Y is the maximum image height, TL is the full length, and wide angle. Each end state, intermediate focal length state, and telephoto end state are represented as values at the time of focusing on infinity. Here, the total length TL indicates the distance on the optical axis from the most object side lens surface (first surface in FIG. 1) to the image plane I at the time of infinite focusing. In the lens data, the first column m indicates the order (surface number) of the lens surfaces from the object side along the traveling direction of the light beam, the second column r indicates the curvature radius of each lens surface, and the third column. d is the distance on the optical axis from each optical surface to the next optical surface (surface interval). The fourth column νd and the fifth column nd are Abbe numbers and refractive indices for the d-line (λ = 587.6 nm). Is shown. Further, the radius of curvature of 0.0000 indicates a plane, and the refractive index of air of 1.00000 is omitted. The surface numbers 1 to 32 shown in Table 1 correspond to the numbers 1 to 32 shown in FIG. The lens group focal length indicates the start surface and focal length of each of the first lens group G1 and the second lens group G2.

  Here, the focal length f, the radius of curvature r, the surface interval d, and other length units listed in all the following specification values are generally “mm”, but the optical system is proportionally enlarged or proportional. Since the same optical performance can be obtained even if the image is reduced, the present invention is not limited to this. The description of these symbols and the description of the specification table are the same in the following embodiments.

(Table 1) First Example [Overall Specifications]
Shortest focal length state Intermediate focal length state Longest focal length state f = 8.17997 to 11.84980 to 15.45007
FNo = 3.56351 to 4.12559 to 4.67681
θ = 89.14213 to 88.84958 to 87.50077
Y = 11.20 to 16.50 to 21.60
TL = 129.03610-126.92735-130.10229

[Lens data]
m r d νd nd
Object ∞
1 69.9791 2.5992 54.61 1.729160
2 18.1503 11.9964
3 * 59.7861 1.6095 67.05 1.592010
4 19.6992 6.6980
5 -180.3004 1.3596 67.90 1.593190
6 20.0353 1.9994
7 22.6462 5.9982 25.45 1.805180
8 318.7364 2.9186
9 -36.6413 1.1996 67.90 1.593190
10 249.8233 D1
11 42.6063 1.8695 44.81 1.744000
12 641.2576 1.0000
13 -16.4939 0.8000 40.66 1.883000
14 -19.2028 2.0000
15 -66.7649 0.8000 40.66 1.883000
16 14.2924 3.4000 47.14 1.670030
17 -15.7897 D2
18 0.0000 2.0500 Aperture stop S
19 -9.5349 0.8000 40.66 1.883000
20 -20.6586 2.7500 58.82 1.518230
21 -9.9800 0.2000
22 20.8047 4.8700 38.03 1.603420
23 -14.8489 0.7000 40.66 1.883000
24 -24.1607 0.2000
25 -58.0012 0.7000 40.66 1.883000
26 17.7676 2.8000 82.57 1.497820
27 941.9509 0.5000
28 68.2847 0.7000 40.66 1.883000
29 23.1398 4.3500 82.57 1.497820
30 -29.9823 0.2175
31 225.0000 1.7000 70.45 1.487490
32 -80.0000 BF
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length 1st lens group 1 -10.91
Second lens group 11 27.50
2A lens group 11 40.00
Second B lens group 19 44.00

  In the fisheye zoom lens ZL1, the third surface is formed in an aspheric shape. The following Table 2 shows aspheric data, that is, the values of the conic constant K and the aspheric constants A4 to A10.

(Table 2)
[Aspherical data]
K A4 A6 A8 A10
3rd surface 1.0000 2.04342E-06 -1.19834E-08 -1.95003E-11 0.00000E + 00

  In the fisheye zoom lens ZL1, the axial air gap D1 between the first lens group G1 and the second lens group G2 and the back focus BF change as described above. Further, the distance D1 on the object side and the distance D2 on the image side of the focusing lens group G2F change during focusing. Table 3 below shows variable intervals in the respective focal length states of the shortest focal length state (W), the intermediate focal length state (M), and the longest focal length state (T) in the infinitely focused state and the closest focused state. Show. Note that f represents the focal length of the entire system, β represents the magnification, and D0 represents the distance from the surface closest to the object (first surface) of the fisheye zoom lens ZL1 to the object. Further, the back focus BF indicates the distance on the optical axis from the lens surface closest to the image plane (the 31st surface in FIG. 1) to the image plane I. The same applies to the following embodiments.

(Table 3)
[Variable interval data]
Infinity close W M T W M T
f 8.17997 11.84980 15.45007
β -0.03333 -0.03333 -0.03333
D0 0.0000 0.0000 0.0000 223.4242 334.4600 442.9260
D1 18.71674 7.35774 1.45774 19.24919 7.69258 1.71937
D2 3.48126 3.48126 3.48126 2.94882 3.14643 3.21963
BF 38.05242 47.30267 56.37761 38.05242 47.30267 56.37761

  Table 4 below shows values corresponding to the conditional expressions in the fish-eye zoom lens ZL1. In Table 4, Yw is the maximum image height in the shortest focal length state, fw is the focal length of the entire system in the shortest focal length state, θw is the maximum shooting half field angle [°] in the shortest focal length state, and Yt is The maximum image height in the longest focal length state, ft is the focal length of the entire system in the longest focal length state, θt is the maximum shooting half field angle [°] in the longest focal length state, and nd2ap2 is in the second A lens group G2A. The average value of the refractive index with respect to the d-line of the medium of the positive lens, νd2ap2 is the average value of the Abbe number with respect to the d-line of the medium of the positive lens of the second A lens group G2, and nd2an2 is the negative lens of the second A lens group G2A. Νd2an2 is the average value of the Abbe number for the d-line of the medium of the negative lens included in the second A lens group G2A, and f1 is the first value. The focal length of the lens group G1, f2 is the focal length of the second lens group G2, f2A2 is the focal length of the second A lens group G2A, f2B2 is the focal length of the second B lens group G2B, and f2F is the focusing lens group. The focal length of G2F, r1 is the radius of curvature of the object-side lens surface of the lens closest to the object side of the first lens group G1, and r2 is the image-side lens surface of the lens closest to the object side of the first lens group G1. The radius of curvature, Bfw represents the back focus in the shortest focal length state, and TLw represents the total optical length in the shortest focal length state. The description of the reference numerals is the same in the following embodiments.

(Table 4)
nd2ap2 = 1.707
νd2ap2 = 45.98
nd2an2 = 1.883
νd2an2 = 40.66
f2F = 40.00

[Values for conditional expressions]
(1) Yw / {2 × fw × sin (θw / 2)} = 0.98
(2) Yt / {2 × ft × sin (θt / 2)} = 1.01
(3) θw = 89.2
(4) θt = 87.6
(5) nd2an2-nd2ap2 = 0.18
(6) νd2ap2-νd2an2 = 5.32
(7) f2 / (− f1) = 2.52
(8) | f2A2 | / (− f1) = 3.67
(9) | f2B2 | / (− f1) = 4.03
(10) | f2F | / (− f1) = 3.67
(11) (r1 + r2) / (r1-r2) = 1.70
(12) Bfw / fw = 4.7
(13) TLw / fw = 15.8

  Thus, this fish-eye zoom lens ZL1 satisfies all the conditional expressions (1) to (13).

  FIG. 2A is a spherical aberration diagram, astigmatism diagram, distortion diagram, magnification chromatic aberration diagram, and coma aberration diagram of the fish-eye zoom lens ZL1 in the shortest focal length state and the longest focal length state when focusing on infinity. 3 (a) and FIG. 2 (b) are spherical aberration diagrams, astigmatism diagrams, distortion diagrams, lateral chromatic aberration diagrams, and coma aberration diagrams in the shortest focal length state and the longest focal length state at the closest focus. And it shows in FIG.3 (b). In each aberration diagram, FNO represents an F number, NA represents a numerical aperture, and Y represents an image height. The spherical aberration diagram shows the F-number or numerical aperture value corresponding to the maximum aperture, the astigmatism diagram and the distortion diagram show the maximum image height, and the coma diagram shows the value of each image height. . d represents a d-line (λ = 587.6 nm), and g represents a g-line (λ = 435.8 nm). In the astigmatism diagram, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane. Also, the same reference numerals as in this example are used in the aberration diagrams of the examples shown below. From these aberration diagrams, it can be seen that the fish-eye zoom lens ZL1 has excellent imaging performance with various aberrations corrected well from the shortest focal length state to the longest focal length state.

[Second Embodiment]
FIG. 4 is a diagram illustrating a configuration of the fish-eye zoom lens ZL2 according to the second embodiment. The fish-eye zoom lens ZL2 shown in FIG. 4 includes, in order from the object side, a first lens group G1 having a negative refractive power and a second lens group G2 having a positive refractive power. The second lens group G2 includes, in order from the object side, a second A lens group G2A having a positive refractive power and a second B lens group G2B having a positive refractive power.

  In the fish-eye zoom lens ZL2, the first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side and a resin surface on a lens surface on the object side of the negative meniscus lens having a convex surface facing the object side. The lens includes a negative lens L21, a biconcave negative lens L13, a biconvex positive lens L14, and a negative meniscus lens L15 having a concave surface facing the object. The second A lens group G2A constituting the second lens group G2 is composed of, in order from the object side, a biconvex positive lens L21, a biconcave negative lens L22, and a positive meniscus lens L23 having a concave surface facing the object side. ing. Further, the second B lens group G2B constituting the second lens group G2 is formed by joining, in order from the object side, a positive meniscus lens L24 having a concave surface facing the object side and a negative meniscus lens L25 having a concave surface facing the object side. A cemented lens in which a biconvex positive lens L26 and a biconcave negative lens L27 are cemented, a positive meniscus lens L28 having a concave surface facing the object side, a negative meniscus lens L29 having a convex surface facing the object side, and a biconvex positive lens L210 Are composed of a cemented lens and a biconvex positive lens L211. The aperture stop S is disposed between the positive meniscus lens L23A and the positive meniscus lens L24 in the second lens group G2.

  This fish-eye zoom lens ZL2 has each lens group on the optical axis so that the distance between the first lens group G1 and the second lens group G2 is reduced upon zooming from the shortest focal length state to the longest focal length state. Configured to move along. The aperture stop S moves integrally with the second lens group G2.

  In the fish-eye zoom lens ZL2, the second lens group G2A is used as a focusing lens group G2F, and focusing from an infinite distance to a close object is performed by moving the focusing lens group G2F to the image side. It is configured. The aperture stop S is fixed with respect to the image plane I at the time of focusing.

  Table 5 below lists values of specifications of the fisheye zoom lens ZL2. The surface numbers 1 to 31 shown in Table 5 correspond to the numbers 1 to 31 shown in FIG.

(Table 5) Second Example [Overall Specifications]
Shortest focal length state Intermediate focal length state Longest focal length state f = 8.18000 to 10.29999 to 15.44996
FNo = 3.54346 to 3.84461 to 4.57616
θ = 89.16716 to 88.95953 to 87.59587
Y = 11.20 to 14.25 to 21.60
TL = 130.49999 to 127.04436 to 128.66084

[Lens data]
m r d νd nd
Object ∞
1 67.5793 2.6000 49.62 1.772500
2 18.5261 11.5000
3 * 43.9078 0.1500 36.64 1.560930
4 43.9078 1.6000 55.52 1.696800
5 21.1562 6.7000
6 -52.5032 1.3600 55.52 1.696800
7 60.4041 2.0000
8 45.2835 6.0000 22.74 1.808090
9 -72.6380 2.0000
10 -24.4324 1.2000 66.99 1.593490
11 -244.4887 D1
12 26.6126 2.0000 46.78 1.766840
13 -350.6635 2.2228
14 -42.2731 0.8000 40.66 1.883000
15 32.7826 2.0010
16 -1139.0561 2.0000 46.78 1.766840
17 -20.6459 D2
18 0.0000 1.6508 Aperture stop S
19 -17.7918 2.0000 58.82 1.518230
20 -10.6996 0.8000 40.66 1.883000
21 -20.3800 0.2000
22 25.5572 4.0000 38.03 1.603420
23 -15.5112 0.7000 40.66 1.883000
24 77.5773 1.0000
25 -56.0148 3.0000 82.57 1.497820
26 -15.6748 0.5000
27 67.2833 0.7000 35.73 1.902650
28 24.0620 5.0000 82.57 1.497820
29 -31.9458 0.2000
30 225.0000 2.3000 70.31 1.487490
31 -80.0000 BF
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length 1st lens group 1 -11.80
Second lens group 12 29.51
2A lens group 12 45.30
Second lens group 19 38.41

  In the fisheye zoom lens ZL2, the third surface is formed in an aspherical shape. Table 6 below shows the aspheric data, that is, the values of the conic constant K and the aspheric constants A4 to A10.

(Table 6)
[Aspherical data]
K A4 A6 A8 A10
3rd surface 1.0000 4.80543E-06 5.63742E-10 5.22458E-12 0.00000E + 00

  In the fisheye zoom lens ZL2, the axial air distance D1 and the back focus BF between the first lens group G1 and the second lens group G2 change during zooming as described above. Further, the distance D1 on the object side and the distance D2 on the image side of the focusing lens group G2F change during focusing. The following Table 7 shows variable intervals in the respective focal length states of the shortest focal length state (W), the intermediate focal length state (M), and the longest focal length state (T) in the infinitely focused state and the closest focused state. Show.

(Table 7)
[Variable interval data]
Infinity close W M T W M T
f 8.18000 10.29999 15.44996
β -0.03333 -0.03333 -0.03333
D0 0.0000 0.0000 0.0000 223.5480 287.7651 443.1073
D1 21.52217 12.76419 1.50000 22.10765 13.21463 1.82330
D2 4.69325 4.69325 4.69325 4.10778 4.24281 4.36995
BF 38.09999 43.40234 56.28301 38.09999 43.40234 56.28301

  Table 8 below shows values corresponding to the conditional expressions in the fish-eye zoom lens ZL2.

(Table 8)
nd2ap2 = 1.767
νd2ap2 = 46.78
nd2an2 = 1.883
νd2an2 = 40.66
f2F = 45.3

[Values for conditional expressions]
(1) Yw / {2 × fw × sin (θw / 2)} = 0.98
(2) Yt / {2 × ft × sin (θt / 2)} = 1.01
(3) θw = 89.2
(4) θt = 87.6
(5) nd2an2-nd2ap2 = 0.12
(6) νd2ap2−νd2an2 = 6.12
(7) f2 / (− f1) = 2.50
(8) | f2A2 | / (− f1) = 3.84
(9) | f2B2 | / (− f1) = 3.26
(10) | f2F | / (− f1) = 3.84
(11) (r1 + r2) / (r1-r2) = 1.76
(12) Bfw / fw = 4.7
(13) TLw / fw = 16.0

  Thus, the fish-eye zoom lens ZL2 satisfies all the conditional expressions (1) to (13).

  FIG. 5A is a spherical aberration diagram, astigmatism diagram, distortion diagram, magnification chromatic aberration diagram, and coma aberration diagram of the fish-eye zoom lens ZL2 in the shortest focal length state and the longest focal length state when focusing on infinity. FIG. 5A shows a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a lateral chromatic aberration diagram, and a coma aberration diagram in the shortest focal length state and the longest focal length state at the closest focus. And shown in FIG. From these aberration diagrams, it can be seen that the fish-eye zoom lens ZL2 has excellent imaging performance with various aberrations corrected well from the shortest focal length state to the longest focal length state.

[Third embodiment]
FIG. 7 is a diagram illustrating a configuration of the fish-eye zoom lens ZL3 according to the third embodiment. The fish-eye zoom lens ZL3 shown in FIG. 7 includes, in order from the object side, a first lens group G1 having a negative refractive power and a second lens group G2 having a positive refractive power. The second lens group G2 includes, in order from the object side, a second A lens group G2A having a positive refractive power and a second B lens group G2B having a positive refractive power.

  In the fisheye zoom lens ZL3, the first lens group G1 includes, in order from the object side, a negative meniscus lens-shaped negative lens L11 having a convex surface toward the object side, in which the lens surface on the object side is formed in an aspheric shape. The lens includes a biconvex positive lens L12, a negative meniscus lens L13 having a convex surface facing the object side, a biconcave negative lens L14, and a biconvex positive lens L15. The second A lens group G2A constituting the second lens group G2 includes, in order from the object side, a biconvex positive lens L21, a negative meniscus lens L22 having a concave surface facing the object side, and a biconcave negative lens L23 and a biconvex lens. It is composed of a cemented lens in which a positive lens L24 is cemented. The second B lens group G2B constituting the second lens group G2 includes, in order from the object side, a negative meniscus lens L25 having a concave surface directed toward the object side, a biconvex positive lens L26, a biconcave negative lens L27, and a biconvex positive lens. The lens includes a cemented lens that joins L28, a cemented lens that joins a biconvex positive lens L29 and a biconcave negative lens L210, and a biconvex positive lens L211. The aperture stop S is disposed between the biconvex positive lens L24 and the negative meniscus lens L25 in the second lens group G2.

  This fish-eye zoom lens ZL3 has each lens group on the optical axis so that the distance between the first lens group G1 and the second lens group G2 is reduced upon zooming from the shortest focal length state to the longest focal length state. Configured to move along. The aperture stop S moves integrally with the second lens group G2.

  In the fish-eye zoom lens ZL3, the second lens group G2A is used as a focusing lens group G2F, and focusing from an infinite distance to a close object is performed by moving the focusing lens group G2F to the image side. It is configured. The aperture stop S is fixed with respect to the image plane I at the time of focusing.

  Table 9 below lists values of specifications of the fisheye zoom lens ZL3. The surface numbers 1 to 29 shown in Table 9 correspond to the numbers 1 to 29 shown in FIG.

(Table 9) Third Example [Overall Specifications]
Shortest focal length state Intermediate focal length state Longest focal length state f = 8.17936 to 11.85140 to 15.45401
FNo = 3.54346 to 3.84461 to 4.57616
θ = 89.16716 to 88.95953 to 87.59587
Y = 11.20 to 16.50 to 21.60
TL = 122.94470-120.88332-123.97692

[Lens data]
m r d νd nd
Object ∞
1 * 134.2522 2.6000 66.99 1.593490
2 17.7203 14.0000
3 449.1675 6.0000 58.12 1.622990
4 -372.8103 0.1000
5 65.8905 1.5000 82.57 1.497820
6 12.5469 8.0000
7 -19.9607 1.2000 67.90 1.593190
8 107.8129 0.1000
9 44.4709 3.0000 22.74 1.808090
10 -123.9984 D1
11 76.4207 1.0000 44.81 1.744000
12 -45.7782 1.0000
13 -11.2443 0.8000 40.66 1.883000
14 -11.5293 0.1000
15 -31.7493 0.8000 40.66 1.883000
16 34.5949 2.2000 47.14 1.670030
17 -19.7594 D2
18 0.0000 2.0500 Aperture stop S
19 -11.6294 1.0000 58.96 1.518230
20 -25.6857 0.2000
21 14.7336 3.5737 70.45 1.487490
22 -20.1199 0.8000 40.80 1.883000
23 14.8504 4.0000 35.45 1.592700
24 -15.5769 0.1000
25 -42.8650 0.9300 37.35 1.834000
26 18.2541 4.0000 82.57 1.497820
27 -26.6294 0.1000
28 42.4808 3.0000 66.99 1.593490
29 -43.6747 BF
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length 1st lens group 1 -10.91
Second lens group 11 26.80
Second lens group 11 38.51
Second B lens group 19 40.45

  In the fisheye zoom lens ZL3, the first surface is formed in an aspherical shape. Table 10 below shows the aspheric data, that is, the values of the conic constant K and the aspheric constants A4 to A10.

(Table 10)
[Aspherical data]
K A4 A6 A8 A10
1st surface 3581.9001 1.06441E-05 -9.83205E-09 0.00000E + 00 0.00000E + 00

  In the fisheye zoom lens ZL3, the axial air distance D1 and the back focus BF between the first lens group G1 and the second lens group G2 change during zooming as described above. Further, the distance D1 on the object side and the distance D2 on the image side of the focusing lens group G2F change during focusing. The following Table 11 shows variable intervals in the respective focal length states of the shortest focal length state (W), the intermediate focal length state (M), and the longest focal length state (T) in the infinitely focused state and the closest focused state. Show.

(Table 11)
[Variable interval data]
Infinity close W M T W M T
f 8.17936 11.85140 15.45401
β -0.03333 -0.03333 -0.03333
D0 0.0000 0.0000 0.0000 222.9289 334.0568 442.6231
D1 18.79753 7.71979 1.96753 19.32181 8.05483 2.23182
D2 3.49385 3.49385 3.49385 2.96957 3.15881 3.22956
BF 38.49966 47.51601 56.36187 38.49966 47.51601 56.36187

  Table 12 below shows values corresponding to the conditional expressions in the fish-eye zoom lens ZL3.

(Table 12)
nd2ap2 = 1.707
νd2ap2 = 45.98
nd2an2 = 1.883
νd2an2 = 40.66
f2F = 38.51

[Values for conditional expressions]
(1) Yw / {2 × fw × sin (θw / 2)} = 0.98
(2) Yt / {2 × ft × sin (θt / 2)} = 1.00
(3) θw = 89.1
(4) θt = 88.3
(5) nd2an2-nd2ap2 = 0.18
(6) νd2ap2-νd2an2 = 5.32
(7) | f2A2 | / (− f1) = 3.53
(8) | f2B2 | / (− f1) = 3.71
(9) f2 / (− f1) = 2.46
(10) | f2F | / (− f1) = 3.53
(11) (r1 + r2) / (r1-r2) = 1.30
(12) Bfw / fw = 4.7
(13) TLw / fw = 15.0

  Thus, the fish-eye zoom lens ZL3 satisfies all the conditional expressions (1) to (13).

  FIG. 8A is a spherical aberration diagram, astigmatism diagram, distortion diagram, magnification chromatic aberration diagram, and coma aberration diagram of the fish-eye zoom lens ZL3 in the shortest focal length state and the longest focal length state when focusing at infinity. And FIG. 9A shows a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a lateral chromatic aberration diagram, and a coma aberration diagram in the shortest focal length state and the longest focal length state at the closest focus. And it shows in FIG.9 (b). From these aberration diagrams, it can be seen that the fish-eye zoom lens ZL3 has excellent imaging performance with various aberrations corrected well from the shortest focal length state to the longest focal length state.

[Fourth embodiment]
FIG. 10 is a diagram illustrating a configuration of the fish-eye zoom lens ZL4 according to the fourth embodiment. The fish-eye zoom lens ZL4 shown in FIG. 10 includes, in order from the object side, a first lens group G1 having a negative refractive power and a second lens group G2 having a positive refractive power. The second lens group G2 includes, in order from the object side, a second A lens group G2A having a positive refractive power and a second B lens group G2B having a positive refractive power.

  In this fisheye zoom lens ZL4, the first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface directed toward the object side, a lens surface on the object side formed in an aspherical shape, and a convex surface on the object side Negative lens L12 having a negative meniscus lens shape, a biconcave negative lens L13, a biconvex positive lens L14, and a negative meniscus lens L15 having a concave surface facing the object side. The second A lens group G2A constituting the second lens group G2 is composed of a negative meniscus lens L21 having a concave surface directed toward the object side and a biconvex positive lens L22 in order from the object side. The second B lens group G2B constituting the second lens group G2 is a cemented lens in which a biconcave negative lens L23 and a biconvex positive lens L24 are cemented in order from the object side, and a biconvex positive lens L25 and a concave surface on the object side. Are composed of a cemented lens cemented with a negative meniscus lens L26 facing and a biconvex positive lens L29. The aperture stop S is disposed between the biconvex positive lens L22 and the biconcave negative lens L23 in the second lens group G2.

  This fish-eye zoom lens ZL4 has each lens group on the optical axis so that the distance between the first lens group G1 and the second lens group G2 is reduced upon zooming from the shortest focal length state to the longest focal length state. Configured to move along. The aperture stop S moves integrally with the second lens group G2.

  In the fish-eye zoom lens ZL4, the second A lens group G2A is used as a focusing lens group G2F, and focusing from an infinite distance to a close object is performed by moving the focusing lens group G2F to the image side. It is configured. The aperture stop S is fixed with respect to the image plane I at the time of focusing.

  Table 13 below provides values of specifications of the fisheye zoom lens ZL4. The surface numbers 1 to 26 shown in Table 13 correspond to the numbers 1 to 26 shown in FIG.

(Table 13) Fourth Example [Overall Specifications]
Shortest focal length state Intermediate focal length state Longest focal length state f = 8.19920 to 11.88237 to 15.49860
FNo = 4.08383 to 4.69320 to 5.29206
θ = 89.27824 to 84.75147 to 87.33028
Y = 11.20 to 16.00 to 21.60
TL = 123.15370 to 120.91399 to 123.96750

[Lens data]
m r d νd nd
Object ∞
1 69.8735 2.6000 54.62 1.729160
2 18.1503 12.0000
3 * 122.8961 1.6100 67.05 1.592010
4 20.5255 6.7000
5 -51.6402 1.3600 67.87 1.593190
6 20.2017 2.0000
7 26.1683 6.0000 25.45 1.805180
8 -1441.0075 2.9186
9 -31.4447 1.2000 67.87 1.593190
10 -57.4943 D1
11 -16.9086 1.5000 54.61 1.729160
12 -21.1202 0.1000
13 59.2584 3.0000 50.84 1.658440
14 -23.5075 D2
15 0.0000 2.2000 Aperture stop S
16 -13.6713 0.8000 40.65 1.883000
17 22.6342 2.7500 58.82 1.518230
18 -15.9415 0.2000
19 15.2283 4.5000 38.05 1.603420
20 -10.8448 0.7000 40.65 1.883000
21 -16.1285 0.5000
22 -22.9655 0.7000 40.65 1.883000
23 13.3855 5.0000 82.56 1.497820
24 -15.3365 0.2000
25 74.1235 2.0000 65.44 1.603000
26 -129.2935 BF
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length 1st lens group 1 -11.02
Second lens group 11 27.28
2nd lens group 11 30.22
2B lens group 16 53.10

  In the fisheye zoom lens ZL4, the third surface is formed in an aspherical shape. Table 14 below shows the aspheric data, that is, the values of the conic constant K and the aspheric constants A4 to A10.

(Table 14)
[Aspherical data]
K A4 A6 A8 A10
3rd surface 1.0000 2.04342E-06 -1.19834E-08 -1.95003E-11 0.00000E + 00

  In the fisheye zoom lens ZL4, the on-axis air distance D1 between the first lens group G1 and the second lens group G2 and the back focus BF change as described above. Further, the distance D1 on the object side and the distance D2 on the image side of the focusing lens group G2F change during focusing. The following Table 15 shows variable intervals in the respective focal length states of the shortest focal length state (W), the intermediate focal length state (M), and the longest focal length state (T) in the infinitely focused state and the closest focused state. Show.

(Table 15)
[Variable interval data]
Infinity close W M T W M T
f 8.19920 11.88237 15.49860
β -0.03333 -0.03333 -0.03333
D0 0.0000 0.0000 0.0000 220.0199 334.8221 444.2525
D1 18.71670 7.35774 1.45774 19.72745 7.73955 1.72335
D2 3.48126 3.48126 3.48126 2.47051 3.09945 3.21565
BF 40.41711 49.53636 58.48987 40.41711 49.53636 58.48987

  Table 16 below shows values corresponding to the conditional expressions in the fish-eye zoom lens ZL4.

(Table 16)
nd2ap2 = 1.658
νd2ap2 = 50.84
nd2an2 = 1.729
νd2an2 = 54.61
f2F = 30.22

[Values for conditional expressions]
(1) Yw / {2 × fw × sin (θw / 2)} = 0.97
(2) Yt / {2 × ft × sin (θt / 2)} = 1.01
(3) θw = 89.3
(4) θt = 87.3
(5) nd2an2-nd2ap2 = 0.07
(6) νd2ap2-νd2an2 = -3.77
(7) | f2A2 | / (− f1) = 2.74
(8) | f2B2 | / (− f1) = 4.82
(9) f2 / (− f1) = 2.48
(10) | f2F | / (− f1) = 2.74
(11) (r1 + r2) / (r1-r2) = 1.70
(12) Bfw / fw = 4.9
(13) TLw / fw = 15.0

  Thus, the fish-eye zoom lens ZL4 satisfies all the conditional expressions (1) to (13).

  FIG. 11A shows a spherical aberration diagram, astigmatism diagram, distortion diagram, magnification chromatic aberration diagram, and coma aberration diagram in the shortest focal length state and the longest focal length state at the time of focusing on infinity of the fish-eye zoom lens ZL4. FIG. 11B shows the spherical aberration diagram, astigmatism diagram, distortion diagram, magnification chromatic aberration diagram, and coma aberration diagram in the shortest focal length state and the longest focal length state at the closest focus. And shown in FIG. From these aberration diagrams, it can be seen that the fish-eye zoom lens ZL4 has excellent imaging performance with various aberrations corrected well from the shortest focal length state to the longest focal length state.

[Fifth embodiment]
FIG. 13 is a diagram illustrating a configuration of the fish-eye zoom lens ZL5 according to the fifth embodiment. The fisheye zoom lens ZL5 shown in FIG. 13 includes, in order from the object side, a first lens group G1 having a negative refractive power and a second lens group G2 having a positive refractive power. The second lens group G2 includes, in order from the object side, a second A lens group G2A having negative refractive power and a second B lens group G2B having positive refractive power.

  In this fisheye zoom lens ZL5, the first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface directed toward the object side, a lens surface on the object side formed in an aspheric shape, and a convex surface on the object side Negative lens L12 having a negative meniscus lens shape, a biconcave negative lens L13, a biconvex positive lens L14, and a negative meniscus lens L15 having a concave surface facing the object side. Further, the second A lens group G2A constituting the second lens group G2 includes, in order from the object side, a biconvex positive lens L21, a biconcave negative lens L22, and a biconvex positive lens L23. The second B lens group G2B constituting the second lens group G2 includes, in order from the object side, a cemented lens in which a biconcave negative lens L24 and a biconvex positive lens L25 are cemented, a biconvex positive lens L26, and a biconvex positive lens. A cemented lens in which L27 and a negative meniscus lens L28 having a concave surface facing the object side are cemented, a cemented lens in which a biconcave negative lens L29 and a biconvex positive lens L210 are cemented, and the lens surface on the object side have an aspherical shape. It is composed of a positive lens L211 having a biconvex positive lens shape. The aperture stop S is disposed between the biconvex positive lens L23 and the biconcave negative lens L24 in the second lens group G2.

  The fish-eye zoom lens ZL5 has each lens group on the optical axis so that the distance between the first lens group G1 and the second lens group G2 is reduced upon zooming from the shortest focal length state to the longest focal length state. Configured to move along. The aperture stop S moves integrally with the second lens group G2.

  The fish-eye zoom lens ZL5 is a focusing lens group G2F, which is a part of the object side of the second B lens group G2B (a cemented lens in which a biconcave negative lens L24 and a biconvex positive lens L25 are cemented). Focusing on a short-distance object is performed by moving the focusing lens group G2F to the object side. The aperture stop S is fixed with respect to the image plane I at the time of focusing.

  Table 17 below provides values of specifications of the fisheye zoom lens ZL5. The surface numbers 1 to 30 shown in Table 17 correspond to the numbers 1 to 30 shown in FIG.

(Table 17) Fifth Example [Overall Specifications]
Shortest focal length state Intermediate focal length state Longest focal length state f = 8.18000 to 10.30000 to 15.45003
FNo = 3.59334 to 3.88220 to 4.58448
θ = 89.10809 to 88.94882 to 87.53164
Y = 11.20 to 14.25 to 21.60
TL = 131.02131 to 127.68518 to 129.30917

[Lens data]
m r d νd nd
Object ∞
1 68.0000 2.6000 49.62 1.772500
2 18.5000 11.5000
3 * 45.9859 1.6000 55.52 1.696800
4 18.2370 7.7000
5 -45.4954 1.3600 55.52 1.696800
6 314.4427 0.5000
7 38.7826 6.0000 22.74 1.808090
8 -104.3746 2.0802
9 -27.6139 1.2000 55.52 1.696800
10 -263.7528 D1
11 302.7039 3.0000 55.52 1.696800
12 -24.0243 2.1000
13 -18.8570 0.7000 40.66 1.883000
14 227.2447 2.5000
15 35.3051 2.5000 47.14 1.670030
16 -31.9816 1.5000
17 0.0000 D2 Aperture stop S
18 -18.8254 0.7000 40.66 1.883000
19 45.7350 1.5000 22.74 1.808090
20 -57.6149 D3
21 60.6455 3.0000 82.57 1.497820
22 -21.3717 0.2000
23 44.1934 4.2000 82.57 1.497820
24 -17.3980 0.7000 35.73 1.902650
25 -36.2015 0.2000
26 -108.6883 0.7000 40.66 1.883000
27 47.2669 3.2000 82.57 1.497820
28 -35.0235 0.2000
29 * 311.6713 2.3000 70.31 1.487490
30 -85.7503 BF
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length 1st lens group 1 -11.77
Second lens group 11 28.73
2nd lens group 11 43.78
2B lens group 21 43.86

  In the fisheye zoom lens ZL5, the third surface and the 29th surface are formed in an aspherical shape. Table 18 below shows the aspheric data, that is, the values of the conical constant K and the aspheric constants A4 to A10.

(Table 18)
[Aspherical data]
K A4 A6 A8 A10
3rd surface 1.0000 4.77529E-06 -1.56649E-09 2.48628E-11 -1.20711E-13
Surface 29 1.0000 -1.88754E-05 0.00000E + 00 0.00000E + 00 0.00000E + 00

  In the fisheye zoom lens ZL5, the axial air distance D1 and the back focus BF between the first lens group G1 and the second lens group G2 change during zooming as described above. Further, the distance D2 on the object side and the distance D3 on the image side of the focusing lens group G2F change during focusing. Table 19 below shows the variable intervals in the respective focal length states of the shortest focal length state (W), the intermediate focal length state (M), and the longest focal length state (T) in the infinitely focused state and the closest focused state. Show.

(Table 19)
[Variable interval data]
Infinity close W M T W M T
f 8.18000 10.30000 15.45003
β -0.03333 -0.03333 -0.03333
D0 0.0000 0.0000 0.0000 224.4249 288.2899 443.2046
D1 22.68837 14.17784 3.23184 22.68837 14.1778 3.23184
D2 4.52224 4.52224 4.52224 4.27868 4.32236 4.37601
D3 1.41850 1.41850 1.41850 1.66206 1.61839 1.56474
BF 38.65197 43.82638 56.39636 38.65197 43.82638 56.39636

  Table 20 below shows values corresponding to the conditional expressions in the fish-eye zoom lens ZL5.

(Table 20)
nd2ap1 = 1.683
νd2ap1 = 51.33
nd2an1 = 1.883
νd2an1 = 40.66
f2F = -29.64

[Values for conditional expressions]
(1) Yw / {2 × fw × sin (θw / 2)} = 0.98
(2) Yt / {2 × ft × sin (θt / 2)} = 1.01
(3) θw = 89.1
(4) θt = 87.5
(5) nd2an2-nd2ap2 = 0.20
(6) νd2ap2-νd2an2 = 10.67
(7) f2 / (− f1) = 2.44
(8) | f2A2 | / (− f1) = 3.72
(9) | f2B2 | / (− f1) = 3.73
(10) | f2F | / (− f1) = 2.52
(11) (r1 + r2) / (r1-r2) = 1.75
(12) Bfw / fw = 4.7
(13) TLw / fw = 16.0

  As described above, the fish-eye zoom lens ZL5 satisfies all the conditional expressions (1) to (13).

  FIG. 14A is a spherical aberration diagram, astigmatism diagram, distortion diagram, magnification chromatic aberration diagram, and coma aberration diagram of the fish-eye zoom lens ZL5 in the shortest focal length state and the longest focal length state when focusing on infinity. FIG. 14B shows the spherical aberration diagram, astigmatism diagram, distortion diagram, magnification chromatic aberration diagram, and coma aberration diagram in the shortest focal length state and the longest focal length state at the closest focus. And it is shown in FIG. From these aberration diagrams, it can be seen that the fish-eye zoom lens ZL5 has excellent imaging performance with various aberrations corrected well from the shortest focal length state to the longest focal length state.

[Sixth embodiment]
FIG. 16 is a diagram illustrating a configuration of the fish-eye zoom lens ZL6 according to the sixth example. The fish-eye zoom lens ZL6 shown in FIG. 16 includes, in order from the object side, a first lens group G1 having a negative refractive power and a second lens group G2 having a positive refractive power. The second lens group G2 includes, in order from the object side, a second A lens group G2A having negative refractive power and a second B lens group G2B having positive refractive power.

  In this fisheye zoom lens ZL5, the first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface directed toward the object side, a lens surface on the object side formed in an aspheric shape, and a convex surface on the object side Negative lens L12 having a negative meniscus lens shape, a biconcave negative lens L13, a biconvex positive lens L14, and a negative meniscus lens L15 having a concave surface facing the object side. The second A lens group G2A constituting the second lens group G2 is composed of a cemented lens in which, in order from the object side, a biconvex positive lens L21 and a negative meniscus lens L22 having a concave surface facing the object side are cemented. . The second B lens group G2B constituting the second lens group G2 includes, in order from the object side, a cemented lens in which a biconcave negative lens L23 and a biconvex positive lens L24 are cemented, a biconvex positive lens L25, and a biconvex positive lens. A cemented lens in which L26 and a negative meniscus lens L27 having a concave surface facing the object side are cemented, a cemented lens in which a negative meniscus lens L28 having a convex surface facing the object side and a biconvex positive lens L29 are cemented, and a lens on the object side It is composed of a positive lens L210 having a biconvex positive lens shape whose surface is aspherical. The aperture stop S is disposed between the negative meniscus lens L22 and the biconcave negative lens L23 in the second lens group G2.

  This fish-eye zoom lens ZL6 has each lens group on the optical axis so that the distance between the first lens group G1 and the second lens group G2 is reduced upon zooming from the shortest focal length state to the longest focal length state. Configured to move along. The aperture stop S moves integrally with the second lens group G2.

  Further, the fish-eye zoom lens ZL6 has a part on the object side of the second B lens group G2B (a cemented lens in which a biconcave negative lens L23 and a biconvex positive lens L24 are cemented) as a focusing lens group G2F, and from infinity. Focusing on a short-distance object is performed by moving the focusing lens group G2F to the object side. The aperture stop S is fixed with respect to the image plane I at the time of focusing.

  Table 21 below lists values of specifications of the fisheye zoom lens ZL6. Note that surface numbers 1 to 27 shown in Table 21 correspond to numbers 1 to 27 shown in FIG.

(Table 21) Sixth Example [Overall specifications]
Shortest focal length state Intermediate focal length state Longest focal length state f = 5.23221 to 10.29999 to 15.45009
FNo = 3.23577 to 3.90752 to 4.61452
θ = 89.02441 to 88.91460 to 87.58244
Y = 7.00 to 14.25 to 21.60
TL = 147.34818 to 127.56911 to 129.38254

[Lens data]
m r d νd nd
Object ∞
1 68.0000 2.6000 49.62 1.772500
2 18.5000 11.5000
3 * 60.0000 1.6000 55.52 1.696800
4 17.7450 8.0000
5 -60.0000 1.3600 67.00 1.593493
6 57.2805 0.5000
7 32.9480 6.0000 25.64 1.784720
8 -80.2775 2.0802
9 -28.1866 1.2000 55.52 1.696800
10 -226.5056 D1
11 26.8466 2.5000 70.32 1.487490
12 -30.2409 0.7000 40.66 1.883000
13 -34.5886 1.5000
14 0.0000 D2 Aperture stop S
15 -18.4423 0.7000 40.66 1.883000
16 29.4508 1.5000 22.74 1.808090
17 -129.3793 D3
18 95.2550 2.5000 82.57 1.497820
19 -24.5125 0.2000
20 44.7222 3.5000 82.57 1.497820
21 -21.8057 0.7000 40.66 1.883000
22 -50.5999 0.2000
23 879.7895 0.7000 35.72 1.902650
24 32.0000 5.0000 82.57 1.497820
25 -26.5122 0.2000
26 * 225.0000 2.3000 70.32 1.487490
27 -80.0000 BF
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length 1st lens group 1 -11.70
Second lens group 11 29.62
2A lens group 11 33.14
Second lens group 18 55.45

  In the fisheye zoom lens ZL6, the third surface and the 26th surface are formed in an aspherical shape. Table 22 below shows the aspheric data, that is, the values of the conic constant K and the aspheric constants A4 to A10.

(Table 22)
[Aspherical data]
K A4 A6 A8 A10
3rd surface 1.0000 -9.39166E-07 1.76857E-08 -7.16338E-11 6.26142E-14
Face 26 1.0000 -1.28479E-05 0.00000E + 00 0.00000E + 00 0.00000E + 00

  In the fisheye zoom lens ZL6, the axial air distance D1 and the back focus BF between the first lens group G1 and the second lens group G2 change during zooming as described above. Further, the distance D2 on the object side and the distance D3 on the image side of the focusing lens group G2F change during focusing. The following table 23 shows variable intervals in the respective focal length states of the shortest focal length state (W), the intermediate focal length state (M), and the longest focal length state (T) in the infinitely focused state and the closest focused state. Show.

(Table 23)
[Variable interval data]
Infinity close W M T W M T
f 5.23221 10.29999 15.45009
β -0.03333 -0.03333 -0.03333
D0 0.0000 0.0000 0.0000 129.3468 287.7536 442.9204
D1 53.35611 20.75070 9.52944 53.35611 20.75070 9.52944
D2 4.90043 4.90043 4.90043 3.64427 4.68676 4.76281
D3 1.01235 1.01235 1.01235 2.26851 1.22602 1.14997
BF 31.03908 43.86543 56.90011 31.03909 43.86544 56.90012

  Table 24 below shows values corresponding to the conditional expressions in the fish-eye zoom lens ZL6.

(Table 24)
nd2ap2 = 1.487
νd2ap2 = 70.32
nd2an2 = 1.883
νd2an2 = 40.66
f2F = -22.81

[Values for conditional expressions]
(1) Yw / {2 × fw × sin (θw / 2)} = 0.95
(2) Yt / {2 × ft × sin (θt / 2)} = 1.01
(3) θw = 89.0
(4) θt = 87.6
(5) nd2an2-nd2ap2 = 0.40
(6) νd2ap2-νd2an2 = 29.66
(7) f2 / (− f1) = 2.53
(8) | f2A2 | / (− f1) = 2.83
(9) | f2B2 | / (− f1) = 4.74
(10) | f2F | / (− f1) = 1.95
(11) (r1 + r2) / (r1-r2) = 1.75
(12) Bfw / fw = 5.9
(13) TLw / fw = 28.2

  Thus, the fish-eye zoom lens ZL6 satisfies all the conditional expressions (1) to (13).

  FIG. 17A shows a spherical aberration diagram, astigmatism diagram, distortion diagram, magnification chromatic aberration diagram, and coma aberration diagram in the shortest focal length state and the longest focal length state at the time of focusing on infinity of the fish-eye zoom lens ZL6. FIG. 17A shows a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a chromatic aberration diagram of magnification, and a coma aberration diagram in the shortest focal length state and the longest focal length state at the closest focus. And it is shown in FIG. From these aberration diagrams, it can be seen that this fish-eye zoom lens ZL6 has excellent imaging performance with various aberrations corrected well from the shortest focal length state to the longest focal length state.

[Seventh embodiment]
FIG. 19 is a diagram illustrating a configuration of a fish-eye zoom lens ZL7 according to the seventh embodiment. The fish-eye zoom lens ZL7 shown in FIG. 19 includes, in order from the object side, a first lens group G1 having a negative refractive power and a second lens group G2 having a positive refractive power. The second lens group G2 includes, in order from the object side, a second A lens group G2A having a positive refractive power and a second B lens group G2B having a positive refractive power.

  In this fish-eye zoom lens ZL7, the first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side, and a resin surface on a lens surface on the object side of the negative meniscus lens having a convex surface facing the object side. The lens includes a negative lens L21, a biconcave negative lens L13, a biconvex positive lens L14, and a negative meniscus lens L15 having a concave surface facing the object. The second A lens group G2A constituting the second lens group G2 is composed of a positive meniscus lens L21 having a convex surface facing the object side, a biconcave negative lens L22, and a biconvex positive lens L23 in order from the object side. ing. Further, the second B lens group G2B constituting the second lens group G2 is formed by joining, in order from the object side, a positive meniscus lens L24 having a concave surface facing the object side and a negative meniscus lens L25 having a concave surface facing the object side. A cemented lens in which a biconvex positive lens L26 and a biconcave negative lens L27 are cemented, a positive meniscus lens L28 having a concave surface facing the object side, a negative meniscus lens L29 having a convex surface facing the object side, and a biconvex positive lens L210 Are composed of a cemented lens and a biconvex positive lens L211. The aperture stop S is disposed between the biconvex positive lens L23 and the positive meniscus lens L24 in the second lens group G2.

  The fish-eye zoom lens ZL7 has each lens group on the optical axis so that the distance between the first lens group G1 and the second lens group G2 is reduced upon zooming from the shortest focal length state to the longest focal length state. Configured to move along. The aperture stop S moves integrally with the second lens group G2.

  In addition, the fish-eye zoom lens ZL7 uses a part of the image side of the second A lens group G2A (biconvex positive lens L23) as a focusing lens group G2F. The lens group G2F is configured to move to the image side. The aperture stop S is fixed with respect to the image plane I at the time of focusing.

  Table 25 below lists values of specifications of the fisheye zoom lens ZL7. The surface numbers 1 to 31 shown in Table 25 correspond to the numbers 1 to 31 shown in FIG.

(Table 25) Seventh Example [Overall specifications]
Shortest focal length state Intermediate focal length state Longest focal length state f = 8.18000 to 10.29999 to 15.44986
FNo = 3.52617 to 3.81480 to 4.51614
θ = 89.12889 to 88.96674 to 87.58446
Y = 11.20 to 14.25 to 21.60
TL = 130.43790 to 126.74513 to 127.92269

[Lens data]
m r d νd nd
Object ∞
1 67.5793 2.6000 49.62 1.772500
2 18.5261 11.5000
3 * 43.9078 0.1500 36.64 1.560930
4 43.9078 1.6000 55.52 1.696800
5 21.1562 6.7000
6 -52.5032 1.3600 55.52 1.696800
7 60.4041 2.0000
8 44.3921 6.0000 22.74 1.808090
9 -75.1106 2.0000
10 -25.4804 1.2000 66.99 1.593490
11 -275.5450 D1
12 26.6489 2.0000 46.78 1.766840
13 379.7263 2.6152
14 -70.8234 0.8000 40.66 1.883000
15 30.8519 D2
16 351.8795 2.0000 46.78 1.766840
17 -21.3165 D3
18 0.0000 1.6508 Aperture stop S
19 -16.3376 2.0000 58.82 1.518230
20 -10.0731 0.8000 40.66 1.883000
21 -21.6179 0.2000
22 24.6482 4.0000 38.03 1.603420
23 -16.6512 0.7000 40.66 1.883000
24 57.6897 1.0000
25 -51.8257 3.0000 82.57 1.497820
26 -14.6027 0.5000
27 58.1781 0.7000 35.73 1.902650
28 24.5283 5.0000 82.57 1.497820
29 -32.2671 0.2000
30 225.0000 2.3000 70.31 1.487490
31 -80.0000 BF
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length First lens group 1 -12.01
Second lens group 12 29.38
2A lens group 12 39.44
Second lens group 19 41.74

  In the fisheye zoom lens ZL7, the third surface is formed in an aspheric shape. Table 26 below shows the aspheric data, that is, the values of the conical constant K and the aspheric constants A4 to A10.

(Table 26)
[Aspherical data]
K A4 A6 A8 A10
3rd surface 1.0000 6.57469E-06 -9.54767E-09 5.22458E-12 0.00000E + 00

  In the fisheye zoom lens ZL7, the on-axis air distance D1 between the first lens group G1 and the second lens group G2 and the back focus BF change as described above. Further, the distance D2 on the object side and the distance D3 on the image side of the focusing lens group G2F change during focusing. The following Table 27 shows variable intervals in the respective focal length states of the shortest focal length state (W), the intermediate focal length state (M), and the longest focal length state (T) in the infinitely focused state and the closest focused state. Show.

(Table 27)
[Variable interval data]
Infinity close W M T W M T
f 8.18000 10.29999 15.44986
β -0.03330 -0.03330 -0.03330
D0 0.0000 0.0000 0.0000 224.5645 288.5402 443.7249
D1 21.79491 12.91688 1.49839 21.79491 12.91688 1.49839
D2 2.41057 2.41057 2.41057 2.63864 2.60315 2.55887
D3 3.15659 3.15659 3.15659 2.92852 2.96401 3.00829
BF 38.49983 43.68510 56.28115 38.49983 43.68510 56.28115

  Table 28 below shows values corresponding to the conditional expressions in the fish-eye zoom lens ZL7.

(Table 28)
nd2ap2 = 1.767
νd2ap2 = 46.78
nd2an2 = 1.883
νd2an2 = 40.66
f2F = 26.26

[Values for conditional expressions]
(1) Yw / {2 × fw × sin (θw / 2)} = 0.98
(2) Yt / {2 × ft × sin (θt / 2)} = 1.01
(3) θw = 89.1
(4) θt = 87.6
(5) nd2an2-nd2ap2 = 0.12
(6) νd2ap2−νd2an2 = 6.12
(7) f2 / (− f1) = 2.45
(8) | f2A2 | / (− f1) = 3.28
(9) | f2B2 | / (− f1) = 3.48
(10) | f2F | / (− f1) = 2.19
(11) (r1 + r2) / (r1-r2) = 1.76
(12) Bfw / fw = 4.7
(13) TLw / fw = 15.9

  Thus, the fish-eye zoom lens ZL7 satisfies all the conditional expressions (1) to (13).

  FIG. 20A shows a spherical aberration diagram, an astigmatism diagram, a distortion diagram, a chromatic aberration diagram, and a coma aberration diagram in the shortest focal length state and the longest focal length state at the time of focusing on infinity of the fish-eye zoom lens ZL7. And FIG. 21A shows a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a chromatic aberration diagram of magnification, and a coma aberration diagram in the shortest focal length state and the longest focal length state at the closest focus. And it is shown in FIG. From these aberration diagrams, it can be seen that the fish-eye zoom lens ZL7 has excellent imaging performance with various aberrations corrected well from the shortest focal length state to the longest focal length state.

[Eighth embodiment]
FIG. 22 is a diagram illustrating a configuration of the fish-eye zoom lens ZL8 according to the eighth embodiment. The fish-eye zoom lens ZL8 shown in FIG. 22 includes, in order from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, and a first lens group having positive refractive power. 3 lens group G3. The second lens group G2 includes, in order from the object side, a second A lens group G2A having a positive refractive power and a second B lens group G2B having a positive refractive power.

  In this fisheye zoom lens ZL8, the first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side, and a resin surface on a lens surface on the object side of the negative meniscus lens having a convex surface facing the object side. The lens includes a negative lens L21, a biconcave negative lens L13, a biconvex positive lens L14, and a negative meniscus lens L15 having a concave surface facing the object. The second A lens group G2A constituting the second lens group G2 is composed of a positive meniscus lens L21 having a convex surface facing the object side, a biconcave negative lens L22, and a biconvex positive lens L23 in order from the object side. ing. Further, the second B lens group G2B constituting the second lens group G2 is formed by joining, in order from the object side, a positive meniscus lens L24 having a concave surface facing the object side and a negative meniscus lens L25 having a concave surface facing the object side. It consists of a lens. The third lens group G3 includes, in order from the object side, a cemented lens in which a biconvex positive lens L31 and a biconcave negative lens L32 are cemented, a positive meniscus lens L33 having a concave surface on the object side, and a convex surface on the object side. In addition, the negative meniscus lens L34 and the biconvex positive lens L35 are cemented to each other, and the biconvex positive lens L36. The aperture stop S is disposed between the biconvex positive lens L23 and the positive meniscus lens L24 in the second lens group G2.

  In the fish-eye zoom lens ZL8, when the magnification is changed from the shortest focal length state to the longest focal length state, the distance between the first lens group G1 and the second lens group G2 decreases, and the second lens group G2 and the third lens. Each lens group is configured to move along the optical axis so that the distance from the group G3 decreases. The aperture stop S moves integrally with the second lens group G2.

  In addition, the fish-eye zoom lens ZL7 uses a part of the image side of the second A lens group G2A (biconvex positive lens L23) as a focusing lens group G2F. The lens group G2F is configured to move to the image side. The aperture stop S is fixed with respect to the image plane I at the time of focusing.

  Table 29 below provides values of specifications of the fisheye zoom lens ZL8. The surface numbers 1 to 31 shown in Table 29 correspond to the numbers 1 to 31 shown in FIG.

(Table 29) Eighth Example [Overall Specifications]
Shortest focal length state Intermediate focal length state Longest focal length state f = 8.18000 to 10.29999 to 15.44994
FNo = 3.64834 to 3.93404 to 4.65980
θ = 89.12962 to 89.13802 to 87.58354
Y = 11.20 to 14.25 to 21.60
TL = 93.47274 to 84.28306 to 72.50394

[Lens data]
m r d νd nd
Object ∞
1 67.5793 2.6000 49.62 1.772500
2 18.5261 11.5000
3 * 43.9078 0.1500 36.64 1.560930
4 43.9078 1.6000 55.52 1.696800
5 21.1562 6.7000
6 -52.5032 1.3600 55.52 1.696800
7 60.4041 2.0000
8 38.6922 6.0000 22.74 1.808090
9 -105.3547 2.0000
10 -26.8571 1.2000 67.00 1.593493
11 -233.2485 D1
12 19.6790 2.0000 46.78 1.766840
13 27.1930 1.8638
14 -302.2340 0.8000 40.66 1.883000
15 37.1795 D2
16 96.0440 2.0000 46.78 1.766840
17 -25.2532 D3
18 0.0000 1.6508 Aperture stop S
19 -16.5086 2.0000 58.82 1.518230
20 -10.3607 0.8000 40.66 1.883000
21 -20.1791 D4
22 21.5497 4.0000 38.03 1.603420
23 -20.9580 0.7000 40.66 1.883000
24 37.7355 1.0000
25 -271.4365 3.0000 82.57 1.497820
26 -18.9418 0.5000
27 72.8898 0.7000 35.72 1.902650
28 24.1266 5.0000 82.57 1.497820
29 -29.2582 0.2000
30 225.0000 2.3000 70.32 1.487490
31 -80.0000 BF
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length 1st lens group 1 -12.35
Second lens group 12 181.02
2A lens group 12 41.08
2B lens group 19 -47.12
Third lens group 22 28.44

  In the fisheye zoom lens ZL8, the third surface is formed in an aspherical shape. Table 30 below shows aspheric data, that is, the values of the conical constant K and the aspheric constants A4 to A10.

(Table 30)
[Aspherical data]
K A4 A6 A8 A10
3rd surface 1.0000 4.92189E-06 -8.01402E-09 5.22458E-12 0.00000E + 00

  In the fisheye zoom lens ZL8, the axial air distance D1 between the first lens group G1 and the second lens group G2, the axial air distance D4 between the second lens group G2 and the third lens group G3, and the back focus. As described above, BF changes at the time of zooming. Further, the distance D2 on the object side and the distance D3 on the image side of the focusing lens group G2F change during focusing. The following Table 31 shows variable intervals in the respective focal length states of the shortest focal length state (W), the intermediate focal length state (M), and the longest focal length state (T) in the infinitely focused state and the closest focused state. Show.

(Table 31)
[Variable interval data]
Infinity close W M T W M T
f 8.18000 10.29999 15.44994
β -0.03330 -0.03330 -0.03330
D0 0.0000 0.0000 0.0000 224.7104 288.6622 443.8374
D1 21.47751 12.64744 1.50470 21.47751 12.64744 1.50470
D2 2.67777 2.67777 2.67777 2.88863 2.86216 2.82479
D3 3.19466 3.19466 3.19466 2.98380 3.01027 3.04764
D4 2.49821 2.13861 1.50223 2.49821 2.13861 1.50223
BF 38.49914 43.51123 55.64466 38.49914 43.51123 55.64466

  Table 32 below shows values corresponding to the conditional expressions in the fish-eye zoom lens ZL8.

(Table 32)
nd2ap2 = 1.767
νd2ap2 = 46.78
nd2an2 = 1.883
νd2an2 = 40.66
f2F = 26.26

[Values for conditional expressions]
(1) Yw / {2 × fw × sin (θw / 2)} = 0.98
(2) Yt / {2 × ft × sin (θt / 2)} = 1.01
(3) θw = 89.1
(4) θt = 87.6
(5) nd2an2-nd2ap2 = 0.12
(6) νd2ap2−νd2an2 = 6.12
(7) f2 / (− f1) = 14.66
(8) | f2A2 | / (− f1) = 3.33
(9) | f2B2 | / (− f1) = − 3.82
(10) | f2F | / (− f1) = 2.13
(11) (r1 + r2) / (r1-r2) = 1.76
(12) Bfw / fw = 4.7
(13) TLw / fw = 16.1

  As described above, the fish-eye zoom lens ZL8 satisfies all the conditional expressions (1) to (13).

  FIG. 23A shows a spherical aberration diagram, an astigmatism diagram, a distortion diagram, a chromatic aberration diagram, and a coma diagram of the fish-eye zoom lens ZL8 in the shortest focal length state and the longest focal length state at the time of focusing on infinity. FIG. 23A shows a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a chromatic aberration diagram of magnification, and a coma aberration diagram in the shortest focal length state and the longest focal length state at the closest focus. And it is shown in FIG. From these aberration diagrams, it can be seen that the fish-eye zoom lens ZL8 has excellent imaging performance with various aberrations corrected well from the shortest focal length state to the longest focal length state.

ZL (ZL1 to ZL8) Fisheye zoom lens G1 First lens group G2 Second lens group G2A Second A lens group G2B 2B lens group G2F Focusing lens group 1 Camera (optical apparatus)

Claims (26)

From the object side,
A first lens group having negative refractive power;
A second lens group having a positive refractive power,
At the time of zooming from the shortest focal length state to the longest focal length state, the distance between the first lens group and the second lens group changes,
The second lens group includes a second A lens group disposed on the object side with the widest air interval, and a second B lens group disposed on the image side with the air interval,
The fisheye zoom lens, wherein the second A lens group includes at least one negative lens.   The fisheye zoom lens according to claim 1, further comprising an aperture stop in the second lens group. From the object side,
A first lens group having negative refractive power;
A second lens group having a positive refractive power,
At the time of zooming from the shortest focal length state to the longest focal length state, the distance between the first lens group and the second lens group changes,
The second lens group includes, in order from the object side, a second A lens group, an aperture stop, and a second B lens group.
The fisheye zoom lens, wherein the second A lens group includes at least one negative lens.   The fisheye zoom lens according to claim 2 or 3, wherein the aperture stop moves integrally with the second lens group at the time of zooming. The fish-eye zoom lens according to any one of claims 1 to 4, wherein a condition of the following formula is satisfied.
0.50 <Yw / {2 × fw × sin (θw / 2)} <2.50
However,
Yw: Maximum image height in the shortest focal length state fw: Total system focal length in the shortest focal length state θw: Maximum shooting half angle of view in the shortest focal length state The fisheye zoom lens according to claim 1, wherein a condition of the following formula is satisfied.
0.50 <Yt / {2 × ft × sin (θt / 2)} <2.50
However,
Yt: Maximum image height in the longest focal length state ft: Focal length of the entire system in the longest focal length state θt: Maximum shooting half angle of view in the longest focal length state   The fish-eye zoom lens according to any one of claims 1 to 6, wherein the fish-eye zoom lens has a maximum image height having a size different between the shortest focal length state and the longest focal length state. The fisheye zoom lens according to claim 1, wherein a condition of the following formula is satisfied.
θw ≧ 50 [°]
However,
θw: Maximum shooting half angle of view in the shortest focal length state The fish-eye zoom lens according to claim 1, wherein a condition of the following formula is satisfied.
θt ≧ 50 [°]
However,
θt: Maximum shooting half angle of view in the longest focal length state   The part of the second lens group is a focusing lens group, and the focusing lens group moves on the optical axis at the time of focusing. Fisheye zoom lens.   At least a part of the second A lens group on the image side or a part of the second B lens group on the object side is a focusing lens group, and the focusing lens group emits light when focusing on a short distance object. The fish-eye zoom lens according to claim 1, wherein the fish-eye zoom lens moves on an axis.   The focusing lens group is at least a part of the second A lens group on the image side, and moves from the object side to the image side when focusing from infinity to a close object. The fisheye zoom lens according to any one of 10.   11. The focusing lens group is a part on the object side of the second B lens group, and moves from the image side to the object side when focusing from infinity to a short distance object. The fisheye zoom lens according to any one of the above. The second A lens group has at least one positive lens,
The fish-eye zoom lens according to claim 1, wherein a condition of the following formula is satisfied.
0.01 <nd2an2-nd2ap2 <0.50
However,
nd2ap2: average value of refractive index with respect to d-line of medium of positive lens of second A lens group nd2an2: average value of refractive index with respect to d-line of medium of negative lens of second A lens group The second A lens group has at least one positive lens,
The fish-eye zoom lens according to claim 1, wherein the condition of the following formula is satisfied.
−10.0 <νd2ap2-νd2an2 <30.0
However,
νd2ap2: average value of Abbe number with respect to d-line of medium of positive lens included in the second A lens group νd2an2: average value of Abbe number with respect to d-line of medium of negative lens included in the second A lens group The fish-eye zoom lens according to claim 1, wherein a condition of the following formula is satisfied.
1.80 <f2 / (− f1) <3.20
However,
f1: Focal length of the first lens group f2: Focal length of the second lens group The fisheye zoom lens according to any one of claims 1 to 16, wherein the following expression is satisfied.
1.00 <| f2A2 | / (− f1) <6.00
However,
f2A2: focal length of the second lens group f1: focal length of the first lens group The fisheye zoom lens according to any one of claims 1 to 17, wherein a condition of the following formula is satisfied.
1.00 <| f2B2 | / (− f1) <7.50
However,
f2B2: focal length of the second B lens group f1: focal length of the first lens group The fish-eye zoom lens according to claim 1, wherein the condition of the following formula is satisfied.
1.00 <| f2F | / (− f1) <6.00
However,
f2F: focal length of the focusing lens group f1: focal length of the first lens group The fisheye zoom lens according to any one of claims 1 to 19, wherein the following expression is satisfied.
0.80 <(r1 + r2) / (r1-r2) <2.30
However,
r1: radius of curvature of the lens surface on the object side of the lens closest to the object side of the first lens group r2: radius of curvature of the lens surface on the image side of the lens closest to the object side of the first lens group The fisheye zoom lens according to any one of claims 1 to 20, wherein the following expression is satisfied.
3.5 <Bfw / fw <8.0
However,
Bfw: Back focus in the shortest focal length state fw: Total system focal length in the shortest focal length state   The fish-eye zoom lens according to any one of claims 1 to 21, wherein the optical axis is linear throughout the entire system.   The fisheye zoom lens according to any one of claims 1 to 22, wherein the fisheye zoom lens is configured only by a refractive system. The fisheye zoom lens according to any one of claims 1 to 23, wherein a condition of the following formula is satisfied.
12.0 <TLw / fw <18.0
However,
TLw: total optical length in the shortest focal length state fw: focal length of the entire system in the shortest focal length state   An optical apparatus comprising the fisheye zoom lens according to any one of claims 1 to 24. A method for manufacturing a fish-eye zoom lens having, in order from the object side, a first lens group having a negative refractive power and a second lens group having a positive refractive power,
Arrangement is made so that the distance between the first lens group and the second lens group changes at the time of zooming from the shortest focal length state to the longest focal length state;
As the second lens group, a second A lens group disposed on the object side with the widest air interval and a second B lens group disposed on the image side with the air interval are arranged,
A fish-eye zoom lens, wherein at least one negative lens is disposed in the second A lens group.

Images