JP6623651B2 - Fisheye zoom lens and optical equipment - Google Patents

Description

The present invention relates to a fisheye zoom lens and an optical device.

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

JP 2012-022109 A

The fish-eye zoom lens according to the first aspect of 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. At the time of zooming from the distance state to the longest focal length state, the distance between the first lens group and the second lens group changes, and a part of the second lens group is a focusing lens group. The lens group moves on the optical axis and satisfies the following condition .
0.50 <Yw / {2 × fw × sin (θw / 2)} <2.50
θw ≧ 70 [°]
However,
Yw: maximum image height in the shortest focal length state
fw: focal length of the entire system in the shortest focal length state
θw: maximum photographing half angle of view in the shortest focal length state

  A fish-eye zoom lens according to a second aspect of 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. At the time of zooming from the distance state to the longest focal length state, the distance between the first lens group and the second lens group changes, and a part of the second lens group is a focusing lens group. The lens group moves on the optical axis and satisfies the following condition.
0.50 <Yt / {2 × ft × sin (θt / 2)} <2.50
θt ≧ 70 [°]
  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 photographing half angle of view in the longest focal length state
  A fish-eye zoom lens according to a third aspect of 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. At the time of zooming from the distance state to the longest focal length state, the distance between the first lens group and the second lens group changes, and a part of the second lens group is a focusing lens group. The lens group moves on the optical axis and satisfies the following condition.
1.80 <f2 / (-f1) <3.20
3.5 <Bfw / fw <8.0
  However,
  f1: focal length of the first lens group
  f2: focal length of the second lens group
  Bfw: Back focus in the shortest focal length state
  fw: focal length of the entire system in the shortest focal length state
  A fish-eye zoom lens according to a fourth aspect of 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. At the time of zooming from the distance state to the longest focal length state, the distance between the first lens group and the second lens group changes, and a part of the second lens group is a focusing lens group. The lens group moves on the optical axis and satisfies the following condition.
1.80 <f2 / (-f1) <3.20
θw ≧ 70 [°]
  However,
  f1: focal length of the first lens group
  f2: focal length of the second lens group
  θw: maximum photographing half angle of view in the shortest focal length state
  A fish-eye zoom lens according to a fifth aspect of 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. At the time of zooming from the distance state to the longest focal length state, the distance between the first lens group and the second lens group changes, and a part of the second lens group is a focusing lens group. The lens group moves on the optical axis and satisfies the following condition.
12.0 <TLw / fw <18.0
θw ≧ 70 [°]
  However,
  TLw: total optical length in the shortest focal length state
  fw: focal length of the entire system in the shortest focal length state
  θw: maximum photographing half angle of view in the shortest focal length state

FIG. 2 is a cross-sectional view illustrating a lens configuration of a fisheye zoom lens according to a first example. 4A and 4B are diagrams illustrating various aberrations of the fisheye zoom lens according to the first example in the shortest focal length state, where FIG. 4A illustrates a focusing state at infinity and FIG. 4A and 4B are diagrams illustrating various aberrations of the fisheye zoom lens according to the first example in the longest focal length state, where FIG. 4A illustrates a focusing state at infinity and FIG. FIG. 8 is a cross-sectional view illustrating a lens configuration of a fisheye zoom lens according to Example 2. FIG. 10 is a diagram illustrating various aberrations of the fisheye zoom lens according to Example 2 in the shortest focal length state, where (a) illustrates a focusing state at infinity and (b) illustrates a focusing state at a short distance. FIG. 8 is a diagram illustrating various aberrations of the fisheye zoom lens according to Example 2 in the longest focal length state, where (a) illustrates a focusing state at infinity and (b) illustrates a focusing state at a short distance. FIG. 11 is a cross-sectional view illustrating a lens configuration of a fisheye zoom lens according to Example 3. It is various aberration figures of the shortest focal length state of the fisheye zoom lens which concerns on Example 3, (a) shows an infinity in-focus state, (b) shows a short distance in-focus state. FIG. 10 is a diagram illustrating various aberrations of the fisheye zoom lens according to Example 3 in the longest focal length state, where (a) illustrates a focusing state at infinity and (b) illustrates a focusing state at a short distance. FIG. 14 is a cross-sectional view illustrating a lens configuration of a fisheye zoom lens according to Example 4. 14A and 14B are graphs showing various aberrations of the fisheye zoom lens according to the fourth example in the shortest focal length state, where (a) illustrates a focusing state at infinity and (b) illustrates a focusing state at a short distance. 14A and 14B are diagrams illustrating various aberrations of the fisheye zoom lens according to Example 4 in the longest focal length state, where (a) illustrates a focusing state at infinity and (b) illustrates a focusing state at a short distance. It is sectional drawing which shows the lens structure of the fisheye zoom lens concerning 5th Example. It is various aberration figure of the shortest focal length state of the fisheye zoom lens which concerns on Example 5, (a) shows an infinity in-focus state, (b) shows a short distance in-focus state. It is various aberration figure of the longest focal length state of the fisheye zoom lens which concerns on a 5th Example, (a) shows an infinity in-focus state, (b) shows a short distance in-focus state. It is sectional drawing which shows the lens structure of the fisheye zoom lens concerning 6th Example. It is various aberration figures of the shortest focal length state of the fisheye zoom lens which concerns on Example 6, (a) shows an infinity in-focus state, (b) shows a short distance in-focus state. FIG. 13 is a diagram illustrating various aberrations of the fisheye zoom lens according to Example 6 in the longest focal length state, where (a) illustrates a focusing state at infinity and (b) illustrates a focusing state at a short distance. It is sectional drawing which shows the lens structure of the fisheye zoom lens concerning 7th Example. FIG. 14 is a diagram illustrating various aberrations of the fisheye zoom lens according to Example 7 in the shortest focal length state, where (a) illustrates a focusing state at infinity and (b) illustrates a focusing state at a short distance. FIG. 14 is a diagram illustrating various aberrations of the fisheye zoom lens according to Example 7 in the longest focal length state, where (a) illustrates a focusing state at infinity and (b) illustrates a focusing state at a short distance. It is sectional drawing which shows the lens structure of the fisheye zoom lens concerning 8th Example. It is a various aberration figure of the shortest focal length state of the fisheye zoom lens concerning 8th Example, (a) shows an infinity in-focus state, (b) shows a short distance in-focus state. It is various aberration figures of the longest focal length state of the fisheye zoom lens which concerns on Example 8, (a) shows an infinity in-focus state, (b) shows a short distance in-focus state. It is sectional drawing of the camera mounted with the said fish-eye zoom lens. It is a flowchart for demonstrating the manufacturing method of the said fish-eye 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 the present 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, Is configured. Further, in the fish-eye zoom lens ZL, at the time of zooming 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 changes. In the fish-eye zoom lens ZL, a part of the second lens group G2 moves on the optical axis as a focusing lens group G2F during focusing. With this configuration, it is possible to obtain a predetermined zoom ratio and obtain good optical performance while securing the back focus in the shortest focal length state.

  It is desirable that the fisheye 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: focal length of the whole system in the shortest focal length state θw: maximum imaging 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 conditional expression (1), it is possible to provide a fish-eye zoom lens of the equal solid angle projection type. If the lower limit value of the conditional expression (1) is not reached, distortion with respect to 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 of 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 of conditional expression (1) to 0.90. In order to further secure the effect of the conditional expression (1), it is preferable to set the lower limit of conditional expression (1) to 0.95. If the value exceeds the upper limit of conditional expression (1), distortion in the equal solid angle projection method is generated on the plus side, which is not preferable. In order to secure the effect of the conditional expression (1), it is preferable to set the upper limit of the conditional expression (1) to 2.20. In order to further secure the effect of the conditional expression (1), it is preferable to set the upper limit 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 of conditional expression (1) to 1.50. In order to further secure the effect of the conditional expression (1), it is desirable to set the upper limit of conditional expression (1) to 1.20.

  It is desirable that the fisheye 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 whole system in the longest focal length state θt: Maximum photographing 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 conditional expression (2), it is possible to provide a fish-eye zoom lens of the equal solid angle projection type. If the lower limit of conditional expression (2) is not reached, distortion with respect to the equal solid angle projection method will occur on the minus side, which is not preferable. In order to secure the effect of the conditional expression (2), it is desirable to set the lower limit of conditional expression (2) to 0.80. In order to further secure the effect of the conditional expression (2), it is preferable to set the lower limit of conditional expression (2) to 0.90. In order to further secure the effect of the conditional expression (2), it is preferable to set the lower limit of conditional expression (2) to 0.95. When the value exceeds the upper limit of conditional expression (2), distortion with respect to the equal solid 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 preferable to set the upper limit of the conditional expression (2) to 2.20. In order to further secure the effect of the conditional expression (2), it is desirable to set the upper limit of conditional expression (2) to 2.00. In order to further secure the effect of the conditional expression (2), it is preferable to set the upper limit of conditional expression (2) to 1.50. In order to further secure the effect of the conditional expression (2), it is preferable to set the upper limit of conditional expression (2) to 1.20.

  It is desirable that the fisheye zoom lens ZL according to the present embodiment has different maximum image heights in the shortest focal length state and the longest focal length state. With this configuration, so-called circular fisheye or diagonal fisheye imaging can be performed in various format sizes.

  In addition, it is desirable that the fisheye zoom lens ZL according to the present embodiment satisfies the following conditional expression (3).

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

  By satisfying conditional expression (3), so-called circular fisheye or diagonal fisheye imaging can be performed in various format sizes. In order to secure the effect of the conditional expression (3), it is desirable to set the lower limit of the conditional expression (3) to 60 °. In order to further secure the effect of the conditional expression (3), it is desirable to set the lower limit of conditional expression (3) to 70 °. In order to further secure the effect of the conditional expression (3), it is preferable to set the lower limit of 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 of conditional expression (3) to 85 [°].

  It is desirable that the fisheye zoom lens ZL according to the present embodiment satisfies the following conditional expression (4).

θt ≧ 50 [°] (4)
However,
θt: maximum photographing half angle of view in the longest focal length state

  By satisfying conditional expression (4), so-called circular fisheye or diagonal fisheye imaging can be performed in various format sizes. In order to secure the effect of the conditional expression (4), it is preferable to set the lower limit of the conditional expression (4) to 60 °. In order to further secure the effect of the conditional expression (4), it is preferable to set the lower limit of 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 of conditional expression (4) to 80 [°]. In order to further secure the effect of the conditional expression (4), it is preferable to set the lower limit of conditional expression (4) to 85 °.

  In the fish-eye zoom lens ZL according to the present embodiment, the second lens group G2 includes, in order from the object side, a second A lens group G2A and a second B lens group G2B. 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 a focusing lens group G2F so that the distance between the lens group G2A and the second B lens group G2B changes. It is desirable to be configured to move on the optical axis. With this configuration, it is possible to obtain good optical performance at the time of focusing even though the focusing lens group G2F is small.

  Further, at the time of focusing from infinity to a close object, at least a part of the second A lens group G2A on the image side becomes a focusing lens group G2F from the object side to the image side when the fisheye zoom lens ZL according to the present embodiment is focused. Desirably, it is configured to move. With this configuration, it is possible to obtain good optical performance at the time of focusing, even though the focusing group is small.

  Alternatively, in the fish-eye zoom lens ZL according to the present embodiment, at the time of focusing from infinity to a close object, a part of the second B lens group G2B on the object side moves from the image side to the object side as a focusing lens group G2F. It is desirable to be constituted so that. With this configuration, it is possible to obtain good optical performance at the time of focusing, even though the focusing group is small.

  In the fisheye zoom lens ZL according to the present embodiment, it is desirable that the second A lens group G2A has at least one negative lens. With this configuration, it is possible to satisfactorily correct spherical aberration and in-field curvature aberration variation during focusing from the shortest focal length state to the longest focal length state.

  In the fisheye 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 <nd2an1-nd2ap1 <0.50 (5)
However,
nd2ap1: average value of the refractive index of the medium of the positive lens of the second A lens group G2A with respect to the d-line nd2an1: average value of the refractive index of the medium of the negative lens of the second A lens group G2A with respect to the d-line

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

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

-10.0 <νd2ap1-νd2an1 <30.0 (6)
However,
νd2ap1: average value of Abbe number of the positive lens medium of the second A lens group G2A with respect to d-line νd2an1: average value of Abbe number of the negative lens medium of the second A lens group G2A with respect to d-line

  Conditional expression (6) defines the difference between the Abbe number of the medium of the positive lens and the medium of the negative lens of the second A lens group G2A with respect to the d-line. If the lower limit of conditional expression (6) is not reached, correction of axial chromatic aberration in the second A lens group G2A will be insufficient, and it will be difficult to correct axial chromatic aberration at the time of focusing in the longest focal length state. In order to secure the effect of the conditional expression (6), it is preferable to set the lower limit 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 of conditional expression (6) to -4.5. When the value exceeds the upper limit of conditional expression (6), axial chromatic aberration in the second A lens group G2A becomes excessively corrected, and it becomes difficult to correct axial chromatic aberration during infinity focusing in the longest focal length state. Absent. In order to secure the effect of the conditional expression (6), it is preferable to set the upper limit of the conditional expression (6) to 20.0. In order to further secure the effect of the conditional expression (6), it is preferable to set the upper limit of conditional expression (6) to 18.0. In order to further secure the effect of the conditional expression (6), it is preferable to set the upper limit of conditional expression (6) to 17.5.

  Further, it is desirable that the fisheye zoom lens ZL according to the present embodiment has an aperture stop S between the first lens group G1 and the second B lens group G2B. With such a configuration, various aberrations such as spherical aberration, coma, and curvature of field can be favorably corrected.

  Alternatively, the fisheye zoom lens ZL according to the present embodiment preferably has an aperture stop S between the second A lens group G2A and the second B lens group G2B. With such a configuration, various aberrations such as spherical aberration, coma, and curvature of field can be favorably corrected.

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

  It is desirable that the fisheye zoom lens ZL according to the present embodiment satisfies the following conditional expression (7).

1.00 <| f2A1 | / (-f1) <25.00 (7)
However,
f2A1: focal length of the second A lens group G2A f1: focal length of the first lens group G1

  Conditional expression (7) defines the ratio of the focal length between the second A lens group G2A and the first lens group G1. When the value goes below the lower limit of conditional expression (7), the focal length of the second A lens group G2A becomes small, and it becomes difficult to correct spherical aberration at the time of focusing in the longest focal length state. In order to secure the effect of the conditional expression (7), it is preferable to set the lower limit of the conditional expression (7) to 1.30. In order to further secure the effect of the conditional expression (7), it is preferable to set the lower limit of conditional expression (7) to 1.65. When the value exceeds the upper limit of conditional expression (7), the focal length of the second A lens group G2A increases, and the first lens group G1 needs to be moved in order to secure the moving distance of the focusing lens group for focusing. The focal length must be reduced, which makes it difficult to correct astigmatism in the longest focal length state, which is not preferable. In order to secure the effect of the conditional expression (7), it is preferable to set the upper limit of the conditional expression (7) to 22.00. In order to further secure the effect of the conditional expression (7), it is desirable to set the upper limit of conditional expression (7) to 17.00. In order to further secure the effect of the conditional expression (7), it is preferable to set the upper limit of conditional expression (7) to 10.00. In order to further secure the effect of the conditional expression (7), it is desirable to set the upper limit of conditional expression (7) to 7.00. In order to further secure the effect of the conditional expression (7), it is preferable to set the upper limit of the conditional expression (7) to 5.00.

  It is desirable that the fisheye zoom lens ZL according to the present embodiment satisfies the following conditional expression (8).

1.00 <| f2B1 | / (-f1) <7.50 (8)
However,
f2B1: focal length of the second B lens group G2B f1: focal length of the first lens group G1

  Conditional expression (8) defines the ratio of the focal length between the second B lens group G2B and the first lens group G1. When the value goes below the lower limit of conditional expression (8), the focal length of the second B lens group G2B becomes small, and it becomes difficult to correct the field curvature aberration in the longest focal length state. In order to secure the effect of the conditional expression (8), it is preferable to set the lower limit of the conditional expression (8) to 1.50. In order to further secure the effect of the conditional expression (8), it is preferable to set the lower limit of conditional expression (8) to 2.00. When the value exceeds the upper limit of conditional expression (8), the focal length of the second B lens group G2B increases, and in order to secure the moving distance of the focusing lens group for focusing, the first lens group G1 is moved. The focal length must be reduced, which makes it difficult to correct astigmatism in the longest focal length state, which is not preferable. In order to secure the effect of the conditional expression (8), it is preferable to set the upper limit of the conditional expression (8) to 6.50. In order to further secure the effect of the conditional expression (8), it is preferable to set the upper limit of the conditional expression (8) to 5.50.

  In addition, it is desirable that the fisheye zoom lens ZL according to the present embodiment satisfies the following conditional expression (9).

1.80 <f2 / (-f1) <3.20 (9)
However,
f1: focal length of the first lens group G1 f2: focal length of the second lens group G2

  Conditional expression (9) defines the ratio of the focal length of the second lens group G2 to the focal length of the first lens group G1. When the value goes below the lower limit of conditional expression (9), 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. In order to secure the effect of the conditional expression (9), it is preferable to set the lower limit of the conditional expression (9) to 2.00. In order to further secure the effect of the conditional expression (9), it is preferable to set the lower limit of the conditional expression (9) to 2.40. When the value exceeds the upper limit of conditional expression (9), the focal length of the second lens group G2 increases, and it is difficult to correct the field curvature aberration in the longest focal length state. In order to secure the effect of the conditional expression (9), it is preferable to set the upper limit of the conditional expression (9) to 2.80. In order to further secure the effect of the conditional expression (9), it is preferable to set the upper limit of conditional expression (9) to 2.60.

  It is desirable that the fisheye 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 length of the focusing lens group G2F to the focal length of the first lens group G1. Within the range of the conditional expression (10), it is possible to reduce the fluctuation of aberration at the time of focusing, such as spherical aberration, coma, and curvature of field. In order to secure the effect of the conditional expression (10), it is preferable to set the lower limit of conditional expression (10) to 1.40. In order to further secure the effect of the conditional expression (10), it is preferable to set the lower limit of the conditional expression (10) to 1.70. In order to secure the effect of the conditional expression (10), it is preferable to set the upper limit 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 of conditional expression (10) to 5.00. In order to further secure the effect of the conditional expression (10), it is preferable to set the upper limit of conditional expression (10) to 4.50.

  It is desirable that the fisheye 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 in the first lens group G1 r2: radius of curvature of the image-side lens surface of the lens closest to the object in the first lens group G1

  Conditional expression (11) defines the shape factor of the lens closest to the object in the first lens group G1. When the value goes below the lower limit of conditional expression (11), it becomes difficult to correct astigmatism in the longest focal length state. In order to secure the effect of the conditional expression (11), it is preferable to set the lower limit of conditional expression (11) to 1.10. In order to further secure the effect of the conditional expression (11), it is preferable to set the lower limit of conditional expression (11) to 1.30. If the value exceeds the upper limit of conditional expression (11), the difficulty of lens processing increases, and astigmatism in the longest focal length state at the time of manufacturing increases, which is not preferable. In order to secure the effect of the conditional expression (11), it is preferable to set the upper limit of the conditional expression (11) to 2.00. In order to further secure the effect of the conditional expression (11), it is preferable to set the upper limit of the conditional expression (11) to 1.80.

  In addition, it is desirable that the fisheye 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: focal length of the entire system 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 value of the conditional expression (12) is not reached, the back focus becomes small, which is not preferable because it interferes with the mirror of the body. In order to secure the effect of the conditional expression (12), it is desirable to set the lower limit of conditional expression (12) to 4.3. In order to further secure the effect of the conditional expression (12), it is preferable to set the lower limit of conditional expression (12) to 4.5. When the value exceeds the upper limit of conditional expression (12), the focal length of the first lens group G1 must be reduced in order to secure a large back focus. As a result, the astigmatism in the longest focal length state is obtained. Correction of aberration becomes difficult, which is not preferable. In order to secure the effect of the conditional expression (12), it is preferable to set the upper limit of the conditional expression (12) to 5.2. In order to further secure the effect of the conditional expression (12), it is preferable to set the upper limit of conditional expression (12) to 5.0.

  Further, in the fisheye zoom lens ZL according to the present embodiment, it is desirable that the optical axis is linear over the entire system. With this configuration, the mechanism for holding the lens can be simplified, and coma at the time of manufacturing can be favorably corrected.

  Further, it is desirable that the fish-eye zoom lens ZL according to the present embodiment is constituted only by a refraction system. With this configuration, the lens is less susceptible to the shape error of the lens surface, and the spherical aberration at the time of manufacturing can be satisfactorily corrected.

  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. When the value goes below the lower limit of conditional expression (13), it is necessary to reduce the number of lenses of the first lens group G1 in order to shorten the total optical length. As a result, the focal length of each lens becomes small, and the field curvature aberration is reduced. It 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 of conditional expression (13) to 14.0. In order to further secure the effect of the conditional expression (13), it is preferable to set the lower limit of conditional expression (13) to 14.5. When the value exceeds the upper limit of conditional expression (13), the focal length of the first lens group G1 must be reduced in order to secure a large overall length. As a result, astigmatism in the longest focal length state is obtained. Is difficult to correct, which is not preferable. In order to secure the effect of the conditional expression (13), it is preferable to set the upper limit 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 conditional expression (13) to 16.5.

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

  Next, a camera that is an optical device including the fisheye zoom lens ZL according to the present embodiment will be described with reference to FIG. The camera 1 is a so-called mirrorless camera of an interchangeable lens type having a fisheye zoom lens ZL according to the present embodiment as a photographing lens 2. In the camera 1, light from an object (not shown) not shown is condensed by a photographing lens 2, and passes through an OLPF (Optical low pass filter) not shown on an imaging surface of an imaging unit 3. To form a subject image. Then, the subject image is photoelectrically converted by a photoelectric conversion element provided in the imaging unit 3, and an image of the subject is generated. 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.

  When the release button (not shown) is pressed by the photographer, the image photoelectrically converted by the imaging unit 3 is stored in a memory (not shown). In this way, the photographer can photograph the subject with the camera 1. In the present embodiment, an example of a mirrorless camera has been described. However, a fish-eye zoom lens ZL according to the present embodiment is applied to a single-lens reflex camera having a quick return mirror in the camera body and observing a subject with a finder optical system. 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 fisheye zoom lens ZL having a two-group or three-group configuration has been described, but the above-described configuration conditions and the like can be applied to other group configurations such as the fourth group, the fifth group, and the like. Further, a configuration in which a lens or a lens group is added closest to the object, or a configuration in which a lens or a lens group is added closest to the image plane may be used. Specifically, a configuration is conceivable in which a lens group whose position with respect to the image plane is fixed at the time of zooming or focusing is closest to the image plane. Further, the lens group refers to a portion having at least one lens, which is separated by an air space that changes during zooming or focusing. Further, in the fish-eye zoom lens ZL of the present embodiment, the first lens group G1 and the second lens group G2 (or the third lens group G3) respectively emit light so that the air gap between the groups changes at the time of zooming. Move along an axis. Further, the lens component refers to a single lens or a cemented lens in which a plurality of lenses are cemented.

  Alternatively, a single or multiple lens groups or partial lens groups may be moved in the optical axis direction to form a focusing lens group for focusing from an object at infinity to an object at a short distance. In this case, the focusing lens group can be applied to autofocus, and is also suitable for driving a motor (such as an ultrasonic motor) for autofocus. In particular, it is preferable that at least a part of the second lens group G2 be a focusing lens group, and that the other lenses be fixed in position with respect to the image plane during focusing. In consideration of the load applied to the motor, it is preferable that the focusing lens group be constituted by a single lens.

  Further, the lens unit or the partial lens unit is moved so as to have a displacement component in a direction orthogonal to the optical axis, or is rotated (oscillated) in an in-plane direction including the optical axis to correct image blur caused by camera shake. It may be a vibration-proof lens group. In particular, as described above, it is preferable that at least a part of the second lens group G2 be 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 deterioration of optical performance due to errors in processing and assembly adjustment is preferably prevented. Further, even when the image plane is displaced, it is preferable because there is little deterioration in the rendering performance. If the lens surface is aspherical, the aspherical surface can be an aspherical surface by grinding, a glass mold aspherical surface in which the glass is formed into an aspherical shape with a mold, or a composite aspherical surface in which the resin is formed into an aspherical shape on the surface of the glass. Any aspheric 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 near or inside the second lens group G2, but the role 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 a high transmittance in a wide wavelength range in order to reduce flare and ghost and achieve high optical performance with high contrast.

  The zoom ratio of the fish-eye zoom lens ZL of the present embodiment is about 1.5 to 5 times.

  Hereinafter, an outline of a method of manufacturing the fisheye zoom lens ZL according to the present embodiment will be described with reference to FIG. First, the first lens group G1 and the second lens group G2 are prepared by arranging the respective lenses (step S100). When the magnification is changed from the shortest focal length state to the longest focal length state, the first lens group G1 and the second lens group G1 are moved to the second focal length state. They are arranged so that the distance between them and the two lens groups G2 changes (step S200). A part of the second lens group G2 is a focusing lens group G2F, and the focusing lens group G2F is disposed so as to move on the optical axis during focusing (step S300).

  Specifically, in the present embodiment, as shown in FIG. 1, for example, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side, and an object-side lens surface formed in an aspherical shape. A negative lens L12 having a negative meniscus lens shape with a convex surface facing the side, a biconcave negative lens L13, a positive meniscus lens L14 with a convex surface facing the object side, and a biconcave negative lens L15 are arranged to form a first lens group G1. A second meniscus lens L21 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 formed by joining a biconcave negative lens L23 and a biconvex positive lens L24. Group G2A, a cemented lens in which 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 biconcave negative lens L29 and a positive meniscus lens L210 having a convex surface facing the object side, and a convex lens 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 arranged are arranged to form a second lens group G2. At this time, the second A lens group G2A is defined as a focusing lens group G2F. The lens groups thus prepared are arranged in the above-described procedure to manufacture the fish-eye zoom lens ZL.

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

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1, 4, 7, 10, 13, 16, 16, 19, and 22 show the configuration and refractive power distribution of the fisheye zoom lens ZL (ZL1 to ZL8) according to each embodiment. It is sectional drawing. The lower part of the cross-sectional view of these fish-eye zoom lenses ZL1 to ZL68 includes the lens groups G1 to G2 (or G3) for zooming from the shortest focal length state (W) to the longest focal length state (T). The direction of movement along the optical axis is indicated by an arrow.

In each embodiment, the height of the aspheric surface in a direction perpendicular to the optical axis is y, and the distance (sag amount) along the optical axis from the tangent plane of the apex of each aspheric surface at the height y to each aspheric surface. Is S (y), the radius of curvature (paraxial radius of curvature) of the reference spherical surface is r, the conic constant is K, and the n-th order aspherical coefficient is An, 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 0. In addition, in the tables of the respective examples, the aspherical surfaces are marked with * on the right side of the surface numbers.

[First embodiment]
FIG. 1 is a diagram illustrating a configuration of the fisheye zoom lens ZL1 according to the first example. 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 this 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 facing the object side, and a convex surface facing the object side having a lens surface on the object side formed in an aspherical shape. , A negative meniscus lens L12 having a negative meniscus lens shape, 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. The second B lens group G2B constituting the second lens group G2 is formed by joining a negative meniscus lens L25 having a concave surface toward the object side and a positive meniscus lens L26 having a concave surface toward the object side in order from the object side. A lens, a cemented lens in which a biconvex positive lens L27 and a negative meniscus lens L28 with 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 with a convex surface facing the object side are joined, It comprises a cemented lens in which a negative meniscus lens L211 having a convex surface facing the object side and a biconvex positive lens L212 are cemented, and a biconvex positive lens L213. Further, the aperture stop S is disposed between the biconvex positive lens L24 and the negative meniscus lens L25 in the second lens group G2.

  Each of the fish-eye zoom lenses ZL1 is positioned on the optical axis such that the distance between the first lens group G1 and the second lens group G2 is reduced when changing the magnification from the shortest focal length state to the longest focal length state. It is configured to move along. The aperture stop S moves integrally with the second lens group G2.

  In the fisheye zoom lens ZL1, the second A lens group G2A is used as a focusing lens group G2F, and focusing from infinity to a close object is performed by moving the focusing lens group G2F to the image side. Is configured. The aperture stop S is fixed with respect to the image plane I during focusing.

  Table 1 below gives data values of the fish-eye zoom lens ZL1. In Table 1, f represents the focal length of the entire system, FNO represents the F number, θ represents a half angle of view (unit is [°]), Y represents the maximum image height, and TL represents the total length, and the wide angle. Each of the end state, the intermediate focal length state, and the telephoto end state is represented as a value at the time of focusing on infinity. Here, the total length TL indicates the distance on the optical axis from the lens surface closest to the object (the first surface in FIG. 1) to the image plane I at the time of infinite focusing. Also, the first column m in the lens data indicates the order (surface number) of the lens surfaces from the object side along the traveling direction of light rays, the second column r indicates the radius of curvature of each lens surface, and the third column m d is the distance on the optical axis (surface distance) from each optical surface to the next optical surface, and the fourth column νd and the fifth column nd are Abbe number and refractive index with respect to d-line (λ = 587.6 nm). Is shown. A radius of curvature of 0.0000 indicates a plane, and a refractive index of air of 1.000000 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 starting surface and the focal length of each of the first lens group G1 and the second lens group G2.

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

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

[Lens data]
mr d νd nd
Physical surface ∞
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 group focal length]
Lens group First surface Focal length First lens group 1 -10.91
Second lens group 11 27.50
Second A lens group 11 40.00
2nd B lens group 19 44.00

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

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

  In this fisheye zoom lens ZL1, the axial air distance D1 between the first lens group G1 and the second lens group G2 and the back focus BF change during zooming, as described above. 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 3 shows the variable intervals in the shortest focal length state (W), the intermediate focal length state (M), and the longest focal length state (T) in the infinity in-focus state and the close focus state. Show. F indicates the focal length of the entire system, β indicates the magnification, and D0 indicates the distance from the most object-side surface (first surface) of the fish-eye zoom lens ZL1 to the object. The back focus BF indicates a distance on the optical axis from the lens surface closest to the image plane (the 31st plane in FIG. 1) to the image plane I. The same applies to the following embodiments.

(Table 3)
[Variable interval data]
Close to infinity 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 respective conditional expressions in the fisheye zoom lens ZL1. In Table 4, Yw represents the maximum image height in the shortest focal length state, fw represents the focal length of the entire system in the shortest focal length state, θw represents the maximum photographing half angle of view [°] in the shortest focal length state, and Yt represents 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 imaging half angle of view [°] in the longest focal length state, and nd2ap1 is the second A lens group G2A. The average value of the refractive index of the medium of the positive lens with respect to the d line, νd2ap1 is the average value of the Abbe number of the medium of the positive lens of the second A lens group G2A with respect to the d line, and nd2an1 is the negative lens of the second A lens group G2A. Νd2an1 is the average value of the Abbe number of the medium of the negative lens of the second A lens group G2A for the d-line, and f1 is the The focal length of the lens group G1, f2 is the focal length of the second lens group G2, f2A1 is the focal length of the second A lens group G2A, f2B1 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 most object-side lens of the first lens group G1, and r2 is the image-side lens surface of the most object-side lens 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 this code is the same in the following embodiments.

(Table 4)
nd2ap1 = 1.707
νd2ap1 = 45.98
nd2an1 = 1.883
νd2an1 = 40.66
f2F = 40.00

[Conditional expression corresponding value]
(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) nd2an1-nd2ap1 = 0.18
(6) νd2ap1-νd2an1 = 5.32
(7) | f2A1 | / (− f1) = 3.67
(8) | f2B1 | / (− f1) = 4.03
(9) f2 / (− f1) = 2.52
(10) | f2F | / (-f1) = 3.67
(11) (r1 + r2) / (r1-r2) = 1.70
(12) Bfw / fw = 4.7
(13) TLw / fw = 15.8

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

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

[Second embodiment]
FIG. 4 is a diagram illustrating a configuration of the fisheye zoom lens ZL2 according to the second example. The fisheye 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 negative meniscus lens having a convex surface facing the object side. It comprises a negative lens L21, a biconcave negative lens L13, a biconvex positive lens L14 having an aspherical shape provided with a layer, 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 includes, 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. The second 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 lens, a cemented lens obtained by cementing a biconvex positive lens L26 and a biconcave negative lens L27, 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. And a double-convex positive lens L211. Further, the aperture stop S is disposed between the positive meniscus lens L23A and the positive meniscus lens L24 in the second lens group G2.

  Each of the fish-eye zoom lenses ZL2 is positioned on the optical axis such that the distance between the first lens group G1 and the second lens group G2 is reduced during zooming from the shortest focal length state to the longest focal length state. It is 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 A lens group G2A is used as a focusing lens group G2F, and focusing from infinity to a close object is performed by moving the focusing lens group G2F to the image side. Is configured. The aperture stop S is fixed with respect to the image plane I during focusing.

  Table 5 below gives data values of the fish-eye 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 Embodiment [Overall Specifications]
Shortest focal length state Intermediate focal length state Longest focal length state f = 8.18000 to 10.29999 to 15.44996
FNo = 3.54346-3.84461-4.57616
θ = 89.16716 to 88.95953 to 87.59587
Y = 11.20 to 14.25 to 21.60
TL = 130.49999-127.04436-128.66084

[Lens data]
mr d νd nd
Physical surface ∞
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 group focal length]
Lens group Start surface Focal length First lens group 1 -11.80
Second lens group 12 29.51
2nd A lens group 12 45.30
2nd B lens group 19 38.41

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

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

  In the fish-eye zoom lens ZL2, the axial air gap D1 between the first lens group G1 and the second lens group G2 and the back focus BF change during zooming, as described above. 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 7 below shows the variable intervals in each of the shortest focal length state (W), the intermediate focal length state (M), and the longest focal length state (T) in the infinity in-focus state and the close focus state. Show.

(Table 7)
[Variable interval data]
Close to infinity 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 respective conditional expressions in the fisheye zoom lens ZL2.

(Table 8)
nd2ap1 = 1.767
νd2ap1 = 46.78
nd2an1 = 1.883
νd2an1 = 40.66
f2F = 45.3

[Conditional expression corresponding value]
(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) nd2an1-nd2ap1 = 0.12
(6) νd2ap1-νd2an1 = 6.12
(7) | f2A1 | / (-f1) = 3.84
(8) | f2B1 | / (− f1) = 3.26
(9) f2 / (− f1) = 2.50
(10) | f2F | / (-f1) = 3.84
(11) (r1 + r2) / (r1-r2) = 1.76
(12) Bfw / fw = 4.7
(13) TLw / fw = 16.0

  Thus, the fisheye zoom lens ZL2 satisfies all of the conditional expressions (1) to (13).

  FIG. 5A shows a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a magnification chromatic aberration diagram, and a coma aberration diagram of the fisheye zoom lens ZL2 in the shortest focal length state and the longest focal length state at the time of focusing on infinity. FIG. 5A shows a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a magnification chromatic aberration diagram, and a coma aberration diagram in the shortest focal length state and the longest focal length state at the time of closest focusing, and FIG. And FIG. 6B. From these aberration diagrams, it can be seen that the fish-eye zoom lens ZL2 has excellent aberrations corrected from the shortest focal length state to the longest focal length state, and has excellent imaging performance.

[Third embodiment]
FIG. 7 is a diagram illustrating a configuration of the fisheye zoom lens ZL3 according to the third example. The fisheye 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 lens L11 having a negative meniscus lens shape in which the lens surface on the object side is formed into an aspherical shape and the convex surface faces the object side. It comprises a biconvex positive lens L12, a negative meniscus lens L13 with the convex surface facing the object side, a biconcave negative lens L14, and a biconvex positive lens L15. The second 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 the 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 facing the object side, a biconvex positive lens L26, a biconcave negative lens L27, and a biconvex positive lens. L28 and a biconvex positive lens L29 and a biconcave negative lens L210, and a biconvex positive lens L211. Further, the aperture stop S is disposed between the biconvex positive lens L24 and the negative meniscus lens L25 in the second lens group G2.

  Each of the fish-eye zoom lenses ZL3 is positioned on the optical axis such that the distance between the first lens group G1 and the second lens group G2 is reduced during zooming from the shortest focal length state to the longest focal length state. It is configured to move along. The aperture stop S moves integrally with the second lens group G2.

  In the fisheye zoom lens ZL3, the second A lens group G2A is used as a focusing lens group G2F, and focusing from infinity to a close object is performed by moving the focusing lens group G2F to the image side. Is configured. The aperture stop S is fixed with respect to the image plane I during focusing.

  Table 9 below gives data values of the fish-eye 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 Embodiment [Overall Specifications]
Shortest focal length state Intermediate focal length state Longest focal length state f = 8.17936 to 11.85140 to 15.45401
FNo = 3.54346-3.84461-4.57616
θ = 89.16716 to 88.95953 to 87.59587
Y = 11.20-16.50-21.60
TL = 122.94470-120.88332-123.97692

[Lens data]
mr d νd nd
Physical surface ∞
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 group focal length]
Lens group First surface Focal length First lens group 1 -10.91
Second lens group 11 26.80
2nd A lens group 11 38.51
2nd B lens group 19 40.45

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

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

  In the fisheye zoom lens ZL3, the axial air gap D1 between the first lens group G1 and the second lens group G2, and the back focus BF change during zooming, as described above. 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 the variable intervals in each of the shortest focal length state (W), the intermediate focal length state (M), and the longest focal length state (T) in the infinity in-focus state and the close focus state. Show.

(Table 11)
[Variable interval data]
Close to infinity 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 each conditional expression in the fisheye zoom lens ZL3.

(Table 12)
nd2ap1 = 1.707
νd2ap1 = 45.98
nd2an1 = 1.883
νd2an1 = 40.66
f2F = 38.51

[Conditional expression corresponding value]
(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) nd2an1-nd2ap1 = 0.18
(6) νd2ap1-νd2an1 = 5.32
(7) | f2A1 | / (-f1) = 3.53
(8) | f2B1 | / (− 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, this fish-eye zoom lens ZL3 satisfies all of the conditional expressions (1) to (13).

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

[Fourth embodiment]
FIG. 10 is a diagram illustrating the configuration of the fisheye zoom lens ZL4 according to the fourth example. 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 fish-eye zoom lens ZL4, 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 convex surface facing the object side in which the lens surface on the object side is formed in an aspherical shape. , A negative meniscus 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 includes, in order from the object side, a negative meniscus lens L21 having a concave surface facing the object side, and a biconvex positive lens L22. 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, and a biconvex positive lens L25 and a concave surface on the object side. And a double-convex positive lens L29. Further, the aperture stop S is arranged between the biconvex positive lens L22 and the biconcave negative lens L23 in the second lens group G2.

  Each of the fish-eye zoom lenses ZL4 is positioned on the optical axis such 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. It is configured to move along. The aperture stop S moves integrally with the second lens group G2.

  In the fisheye zoom lens ZL4, the second A lens group G2A is used as a focusing lens group G2F, and focusing from infinity to a close object is performed by moving the focusing lens group G2F to the image side. Is configured. The aperture stop S is fixed with respect to the image plane I during focusing.

  Table 13 below gives data values of the fish-eye 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 Embodiment [Overall Specifications]
Shortest focal length state Intermediate focal length state Longest focal length state f = 8.19920 to 11.88237 to 15.49860
FNo = 4.08383-4.69320-5.29206
θ = 89.27824 to 84.75147 to 87.33028
Y = 11.20-16.00-21.60
TL = 123.15370 to 120.91399 to 123.96750

[Lens data]
mr d νd nd
Physical surface ∞
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 group focal length]
Lens group Start surface Focal length First lens group 1 -11.02
Second lens group 11 27.28
2nd A lens group 11 30.22
2nd B lens group 16 53.10

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

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

  In the fisheye zoom lens ZL4, the axial air distance D1 between the first lens group G1 and the second lens group G2 and the back focus BF change during zooming, as described above. 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 15 below shows the variable intervals in the shortest focal length state (W), the intermediate focal length state (M), and the longest focal length state (T) in the infinity in-focus state and the close focus state. Show.

(Table 15)
[Variable interval data]
Close to infinity 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 each conditional expression in the fisheye zoom lens ZL4.

(Table 16)
nd2ap1 = 1.658
νd2ap1 = 50.84
nd2an1 = 1.729
νd2an1 = 54.61
f2F = 30.22

[Conditional expression corresponding value]
(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) nd2an1-nd2ap1 = 0.07
(6) νd2ap1-νd2an1 = −3.77
(7) | f2A1 | / (− f1) = 2.74
(8) | f2B1 | / (− 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, this fish-eye zoom lens ZL4 satisfies all of the conditional expressions (1) to (13).

  FIG. 11A shows a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a magnification chromatic aberration diagram, and a coma aberration diagram of the fisheye zoom lens ZL4 in the shortest focal length state and the longest focal length state at the time of focusing on infinity. FIG. 11A shows a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a magnification chromatic aberration diagram, and a coma aberration diagram in the shortest focal length state and the longest focal length state at the time of closest focusing. And FIG. 12 (b). From these aberration diagrams, it can be seen that the fish-eye zoom lens ZL4 has excellent aberrations corrected from the shortest focal length state to the longest focal length state, and has excellent imaging performance.

[Fifth embodiment]
FIG. 13 is a diagram illustrating a configuration of the fisheye zoom lens ZL5 according to the fifth example. 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 a negative refractive power and a second B lens group G2B having a positive refractive power.

  In the fish-eye zoom lens ZL5, 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 convex surface facing the object side in which the lens surface on the object side has an aspheric shape. , A negative meniscus 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 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, a biconvex positive lens L23, and a biconcave negative lens L24 and a biconvex lens. It is composed of a cemented lens in which the positive lens L25 is cemented. In addition, the second B lens group G2B constituting the second lens group G2 is formed by joining, in order from the object side, a biconvex positive lens L26, a biconvex positive lens L27, and a negative meniscus lens L28 having a concave surface facing the object side. It is composed of a lens, a cemented lens in which a biconcave negative lens L29 and a biconvex positive lens L210 are cemented, and a positive lens L211 having a biconvex positive lens shape in which an object-side lens surface is formed in an aspherical shape. Further, the aperture stop S is disposed between the biconvex positive lens L23 and the biconcave negative lens L24 in the second lens group G2.

  Each of the fish-eye zoom lenses ZL5 is positioned on the optical axis such that the distance between the first lens group G1 and the second lens group G2 is reduced when changing the magnification from the shortest focal length state to the longest focal length state. It is configured to move along. The aperture stop S moves integrally with the second lens group G2.

  This fish-eye zoom lens ZL5 is a focusing lens group G2F, which is a part of the second A lens group G2A on the image side (a cemented lens formed by joining a biconcave negative lens L24 and a biconvex positive lens L25). Focusing on a short-distance object is configured to be 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 during focusing.

  Table 17 below gives data values of the fish-eye 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 Embodiment [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 = 131.02131-127.68518-129.30917

[Lens data]
mr d νd nd
Physical surface ∞
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 group focal length]
Lens group Start surface Focal length First lens group 1 -11.77
Second lens group 11 28.73
Second A lens group 11 -176.73
2nd B lens group 21 21.85

  In this fisheye zoom lens ZL5, the third surface and the twenty-ninth surface are formed in an aspherical shape. Table 18 below shows the data of the aspherical surface, that is, the values of the conic constant K and the respective aspherical constants A4 to A10.

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

  In the fisheye zoom lens ZL5, the axial air gap D1 between the first lens group G1 and the second lens group G2 and the back focus BF change during zooming, as described above. 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 each of the shortest focal length state (W), the intermediate focal length state (M), and the longest focal length state (T) in the infinity in-focus state and the close focus state. Show.

(Table 19)
[Variable interval data]
Close to infinity 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 respective conditional expressions in the fisheye zoom lens ZL5.

(Table 20)
nd2ap1 = 1.725
νd2ap1 = 41.80
nd2an1 = 1.883
νd2an1 = 40.66
f2F = -29.64

[Conditional expression corresponding value]
(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) nd2an1-nd2ap1 = 0.16
(6) νd2ap1-νd2an1 = 1.14
(7) | f2A1 | / (-f1) = 15.01
(8) | f2B1 | / (− f1) = 1.86
(9) f2 / (− f1) = 2.44
(10) | f2F | / (-f1) = 2.52
(11) (r1 + r2) / (r1-r2) = 1.75
(12) Bfw / fw = 4.7
(13) TLw / fw = 16.0

  Thus, the fish-eye zoom lens ZL5 satisfies all of the conditional expressions (1) to (13).

  FIG. 14A shows a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a magnification chromatic aberration diagram, and a coma aberration diagram of the fisheye zoom lens ZL5 in the shortest focal length state and the longest focal length state when focusing on infinity. FIG. 14A shows a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a magnification chromatic aberration diagram, and a coma aberration diagram in the shortest focal length state and the longest focal length state at the time of closest focusing, and FIG. 15 (b). From these aberration diagrams, it can be seen that this fish-eye zoom lens ZL5 has excellent correction of various aberrations from the shortest focal length state to the longest focal length state, and has excellent imaging performance.

[Sixth embodiment]
FIG. 16 is a diagram illustrating the configuration of the fisheye 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 a negative refractive power and a second B lens group G2B having a positive refractive power.

  In the fish-eye zoom lens ZL5, 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 convex surface facing the object side in which the lens surface on the object side has an aspheric shape. , A negative meniscus 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 includes, in order from the object side, a cemented lens in which a biconvex positive lens L21 and a negative meniscus lens L22 having a concave surface facing the object side are cemented, 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. In addition, the second B lens group G2B constituting the second lens group G2 is formed by joining, in order from the object side, a biconvex positive lens L25, a biconvex positive lens L26, and a negative meniscus lens L27 having a concave surface facing the object side. A lens, a cemented lens formed by joining a negative meniscus lens L28 having a convex surface to the object side and a biconvex positive lens L29, and a positive lens L210 having a biconvex positive lens shape having an aspherical object-side lens surface It is composed of Further, the aperture stop S is disposed between the negative meniscus lens L22 and the biconcave negative lens L23 in the second lens group G2.

  Each of the fish-eye zoom lenses ZL6 is positioned on the optical axis such that the distance between the first lens group G1 and the second lens group G2 is reduced during zooming from the shortest focal length state to the longest focal length state. It is configured to move along. The aperture stop S moves integrally with the second lens group G2.

  The fish-eye zoom lens ZL6 has a focusing lens group G2F that is a part of the second A lens group G2A on the image side (a cemented lens formed by joining a biconcave negative lens L23 and a biconvex positive lens L24). Focusing on a short-distance object is configured to be 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 during focusing.

  Table 21 below gives data values of the fish-eye zoom lens ZL6. The surface numbers 1 to 27 shown in Table 21 correspond to the numbers 1 to 27 shown in FIG.

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

[Lens data]
mr d νd nd
Physical surface ∞
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 group focal length]
Lens group Start surface Focal length First lens group 1 -11.70
Second lens group 11 29.62
2nd A lens group 11 -251.62
2nd B lens group 18 21.42

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

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

  In the fish-eye zoom lens ZL6, the axial air distance D1 between the first lens group G1 and the second lens group G2 and the back focus BF change during zooming, as described above. 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 the variable intervals in the shortest focal length state (W), the intermediate focal length state (M), and the longest focal length state (T) in the infinity in-focus state and the close focus state. Show.

(Table 23)
[Variable interval data]
Close to infinity 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 respective conditional expressions in the fisheye zoom lens ZL6.

(Table 24)
nd2ap1 = 1.648
νd2ap1 = 46.53
nd2an1 = 1.883
νd2an1 = 40.66
f2F = -22.81

[Conditional expression corresponding value]
(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) nd2an1-nd2ap1 = 0.24
(6) νd2ap1-νd2an1 = 5.87
(7) | f2A1 | / (-f1) = 21.50
(8) | f2B1 | / (− f1) = 1.83
(9) f2 / (− f1) = 2.53
(10) | f2F | / (-f1) = 1.95
(11) (r1 + r2) / (r1-r2) = 1.75
(12) Bfw / fw = 5.9
(13) TLw / fw = 28.2

  As described above, the fisheye zoom lens ZL6 satisfies all of the conditional expressions (1) to (13).

  FIG. 17A shows a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a magnification chromatic aberration diagram, and a coma aberration diagram of the fisheye zoom lens ZL6 in the shortest focal length state and the longest focal length state at the time of focusing on infinity. FIG. 17A shows a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a magnification chromatic aberration diagram, and a coma aberration diagram in the shortest focal length state and the longest focal length state at the time of closest focusing. And FIG. 18 (b). From these aberration diagrams, it can be seen that this fish-eye zoom lens ZL6 has excellent aberrations corrected from the shortest focal length state to the longest focal length state, and has excellent imaging performance.

[Seventh embodiment]
FIG. 19 is a diagram illustrating a configuration of the fisheye zoom lens ZL7 according to the seventh example. The fisheye 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 the 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 negative meniscus lens having a convex surface facing the object side. It comprises a negative lens L21, a biconcave negative lens L13, a biconvex positive lens L14 having an aspherical shape provided with a layer, 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 includes, in order from the object side, a positive meniscus lens L21 having a convex surface facing the object side, a biconcave negative lens L22, and a biconvex positive lens L23. ing. The second 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 lens, a cemented lens obtained by cementing a biconvex positive lens L26 and a biconcave negative lens L27, 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. And a double-convex positive lens L211. Further, the aperture stop S is arranged between the biconvex positive lens L23 and the positive meniscus lens L24 in the second lens group G2.

  Each of the fish-eye zoom lenses ZL7 is positioned on the optical axis such that the distance between the first lens group G1 and the second lens group G2 is reduced when changing the magnification from the shortest focal length state to the longest focal length state. It is configured to move along. The aperture stop S moves integrally with the second lens group G2.

  In the fish-eye zoom lens ZL7, a part of the image side of the second A lens group G2A (a biconvex positive lens L23) is used as a focusing lens group G2F. The movement is performed by moving the lens group G2F to the image side. The aperture stop S is fixed with respect to the image plane I during focusing.

  Table 25 below lists the values of the specifications of the fish-eye 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 Embodiment [Overall Specifications]
Shortest focal length state Intermediate focal length state Longest focal length state f = 8.18000 to 10.29999 to 15.44986
FNo = 3.52617-3.81480-4.51614
θ = 89.12889-88.96674-87.58446
Y = 11.20 to 14.25 to 21.60
TL = 130.43790 to 126.74513 to 127.92269

[Lens data]
mr d νd nd
Physical surface ∞
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 group focal length]
Lens group First surface Focal length First lens group 1 -12.01
Second lens group 12 29.38
2nd A lens group 12 39.44
2nd B lens group 19 41.74

  In this fisheye zoom lens ZL7, the third surface is formed in an aspherical shape. The following Table 26 shows the data of the aspherical surface, that is, the values of the conic constant K and the respective aspherical constants A4 to A10.

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

  In the fish-eye zoom lens ZL7, the axial air gap D1 between the first lens group G1 and the second lens group G2 and the back focus BF change during zooming, as described above. 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 27 below shows the variable intervals in the shortest focal length state (W), the intermediate focal length state (M), and the longest focal length state (T) in the infinity in-focus state and the close focus state. Show.

(Table 27)
[Variable interval data]
Close to infinity 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 fisheye zoom lens ZL7.

(Table 28)
nd2ap1 = 1.767
νd2ap1 = 46.78
nd2an1 = 1.883
νd2an1 = 40.66
f2F = 26.26

[Conditional expression corresponding value]
(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) nd2an1-nd2ap1 = 0.12
(6) νd2ap1-νd2an1 = 6.12
(7) | f2A1 | / (− f1) = 3.28
(8) | f2B1 | / (− f1) = 3.48
(9) f2 / (− f1) = 2.45
(10) | f2F | / (-f1) = 2.19
(11) (r1 + r2) / (r1-r2) = 1.76
(12) Bfw / fw = 4.7
(13) TLw / fw = 15.9

  Thus, the fisheye zoom lens ZL7 satisfies all of the conditional expressions (1) to (13).

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

[Eighth embodiment]
FIG. 22 is a diagram illustrating a configuration of the fisheye zoom lens ZL8 according to the eighth example. The fish-eye zoom lens ZL8 shown in FIG. 22 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, and a second lens group G2 having a positive refractive power. And three lens groups 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 the fish-eye 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 negative meniscus lens having a convex surface facing the object side. It comprises a negative lens L21, a biconcave negative lens L13, a biconvex positive lens L14 having an aspherical shape provided with a layer, 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 includes, in order from the object side, a positive meniscus lens L21 having a convex surface facing the object side, a biconcave negative lens L22, and a biconvex positive lens L23. ing. 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 facing the object side, and a convex surface facing the object side. It comprises a cemented lens in which a negative meniscus lens L34 and a biconvex positive lens L35 are cemented, and a biconvex positive lens L36. Further, the aperture stop S is arranged between the biconvex positive lens L23 and the positive meniscus lens L24 in the second lens group G2.

  In zooming 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 fisheye zoom lens ZL8 reduces the distance between the first lens group G1 and the second lens group G2. 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 the fish-eye zoom lens ZL7, a part of the image side of the second A lens group G2A (a biconvex positive lens L23) is used as a focusing lens group G2F. The movement is performed by moving the lens group G2F to the image side. The aperture stop S is fixed with respect to the image plane I during focusing.

  Table 29 below lists the values of the specifications of the fish-eye 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 Embodiment [Overall Specifications]
Shortest focal length state Intermediate focal length state Longest focal length state f = 8.18000 to 10.29999 to 15.44994
FNo = 3.64834-3.93404-4.65980
θ = 89.12962 to 89.13802 to 87.58354
Y = 11.20 to 14.25 to 21.60
TL = 93.47274-84.28306-72.50394

[Lens data]
mr d νd nd
Physical surface ∞
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 group focal length]
Lens group Start surface Focal length First lens group 1 -12.35
Second lens group 12 181.02
Second A lens group 12 41.08
2nd B lens group 19 -47.12
Third lens group 22 28.44

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

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

  In the fish-eye 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. 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 the variable intervals in the 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 infinity in-focus state and the close focus state. Show.

(Table 31)
[Variable interval data]
Close to infinity 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 fisheye zoom lens ZL8.

(Table 32)
nd2ap1 = 1.767
νd2ap1 = 46.78
nd2an1 = 1.883
νd2an1 = 40.66
f2F = 26.26

[Conditional expression corresponding value]
(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) nd2an1-nd2ap1 = 0.12
(6) νd2ap1-νd2an1 = 6.12
(7) | f2A1 | / (− f1) = 3.33
(8) | f2B1 | / (− f1) = 3.82
(9) f2 / (− f1) = 14.66
(10) | f2F | / (− f1) = 2.13
(11) (r1 + r2) / (r1-r2) = 1.76
(12) Bfw / fw = 4.7
(13) TLw / fw = 16.1

  Thus, the fish-eye zoom lens ZL8 satisfies all of the conditional expressions (1) to (13).

  FIG. 23A shows a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a magnification chromatic aberration diagram, and a coma aberration diagram of the fisheye zoom lens ZL8 in the shortest focal length state and the longest focal length state when focusing on infinity. FIG. 23B 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 time of closest focusing, and FIG. And FIG. 24 (b). From these aberration diagrams, it can be seen that the fish-eye zoom lens ZL8 has excellent correction of various aberrations from the shortest focal length state to the longest focal length state, and has excellent imaging performance.

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

Claims (21)

In order from the object side,
A first lens group having a 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,
A part of the second lens group is a focusing lens group, and at the time of focusing, the focusing lens group moves on the optical axis ,
A fish-eye zoom lens that satisfies the following condition:
0.50 <Yw / {2 × fw × sin (θw / 2)} <2.50
θw ≧ 70 [°]
However,
Yw: maximum image height in the shortest focal length state
fw: focal length of the entire system in the shortest focal length state
θw: maximum photographing half angle of view in the shortest focal length state In order from the object side,
A first lens group having a 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,
A part of the second lens group is a focusing lens group, and at the time of focusing, the focusing lens group moves on the optical axis ,
A fish-eye zoom lens that satisfies the following condition:
0.50 <Yt / {2 × ft × sin (θt / 2)} <2.50
θt ≧ 70 [°]
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 photographing half angle of view in the longest focal length state In order from the object side,
A first lens group having a 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,
A part of the second lens group is a focusing lens group, and at the time of focusing, the focusing lens group moves on the optical axis ,
A fish-eye zoom lens that satisfies the following condition:
1.80 <f2 / (-f1) <3.20
3.5 <Bfw / fw <8.0
However,
f1: focal length of the first lens group
f2: focal length of the second lens group
Bfw: Back focus in the shortest focal length state
fw: focal length of the entire system in the shortest focal length state In order from the object side,
A first lens group having a 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,
A part of the second lens group is a focusing lens group, and at the time of focusing, the focusing lens group moves on the optical axis ,
A fish-eye zoom lens that satisfies the following condition:
1.80 <f2 / (-f1) <3.20
θw ≧ 70 [°]
However,
f1: focal length of the first lens group
f2: focal length of the second lens group
θw: maximum photographing half angle of view in the shortest focal length state In order from the object side,
A first lens group having a 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,
A part of the second lens group is a focusing lens group, and at the time of focusing, the focusing lens group moves on the optical axis ,
A fish-eye zoom lens that satisfies the following condition:
12.0 <TLw / fw <18.0
θw ≧ 70 [°]
However,
TLw: total optical length in the shortest focal length state
fw: focal length of the entire system in the shortest focal length state
θw: maximum photographing half angle of view in the shortest focal length state The fish-eye zoom lens according to any one of claims 2 to 5, wherein the following condition is satisfied.
0.50 <Yw / {2 × fw × sin (θw / 2)} <2.50
However,
Yw: maximum image height in the shortest focal length state fw: focal length of the whole system in the shortest focal length state θw: maximum imaging half angle of view in the shortest focal length state 4. The fish-eye zoom lens according to claim 2, wherein the following condition is satisfied.
θw ≧ 50 [°]
However,
θw: maximum photographing half angle of view in the shortest focal length state The fish-eye zoom lens according to any one of claims 1, 3, 4, and 5, wherein the following condition is satisfied.
θt ≧ 50 [°]
However,
θt: maximum photographing half angle of view in the longest focal length state The fish-eye zoom lens according to any one of claims 1, 3, 4, and 5, wherein the following condition 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 whole system in the longest focal length state θt: Maximum photographing half angle of view in the longest focal length state The fish-eye zoom lens according to any one of claims 1, 2, 4, and 5, wherein the following condition is satisfied.
3.5 <Bfw / fw <8.0
However,
Bfw: back focus in the shortest focal length state fw: focal length of the entire system in the shortest focal length state The fisheye zoom lens according to any one of claims 1 to 10, wherein a maximum image height is different between the shortest focal length state and the longest focal length state. The second lens group is, in order from the object side,
A second A lens group;
A second B lens group;
At the time of focusing, at least a part of the second A lens group on the image side moves on the optical axis as the focusing lens group so that the distance between the second A lens group and the second B lens group changes. The fish-eye zoom lens according to claim 1, wherein: Wherein said 2A lens group, possess at least each one of a negative lens element and a positive lens,
The fish-eye zoom lens according to claim 12 , wherein the following condition is satisfied.
0.01 <nd2an1-nd2ap1 <0.50
However,
nd2ap1: average value of the refractive index of the medium of the positive lens of the second A lens group with respect to the d line nd2an1: average value of the refractive index of the medium of the negative lens of the second A lens group with respect to the d line Wherein said 2A lens group, possess at least each one of a negative lens element and a positive lens,
14. The fish-eye zoom lens according to claim 12, wherein the following condition is satisfied.
-10.0 <νd2ap1-νd2an1 <30.0
However,
νd2ap1: average value of Abbe number of the positive lens medium of the second A lens group with respect to d-line νd2an1: average value of Abbe number of the negative lens medium of the second A lens group with respect to d-line The fisheye zoom lens according to any one of claims 12 to 14, wherein the following condition is satisfied.
1.00 <| f2A1 | / (-f1) <25.00
However,
f2A1: 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 12 to 15, wherein the following condition is satisfied.
1.00 <| f2B1 | / (-f1) <7.50
However,
f2B1: focal length of the second B lens group f1: focal length of the first lens group 17. The fish-eye zoom lens according to claim 1, wherein the following condition 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 fish-eye zoom lens according to any one of claims 1 to 17, wherein the following condition is satisfied.
0.80 <(r1 + r2) / (r1-r2) <2.30
However,
r1: radius of curvature of the object-side lens surface of the lens closest to the object in the first lens group r2: radius of curvature of the image-side lens surface of the lens closest to the object in the first lens group The fish-eye zoom lens according to any one of claims 1 to 18, wherein the optical axis is linear over the entire system. 20. The fish-eye zoom lens according to claim 1, wherein the fish-eye zoom lens is constituted only by a refraction system. An optical apparatus characterized by having a fisheye zoom lens according to any one of claims 1 to 20.

Images