JP5542010B2 - Macro lens - Google Patents

Description

  The present invention relates to an inner focus type macro lens.

  Conventionally, in order from the object side, a positive first group, a negative second group, a positive third group, and a negative fourth group. An inner focus type macro lens in which the first group and the fourth group do not move, the second group moves to the image side, and the third group moves to the object side during focusing to the near-distance object in-focus state. It is known (for example, refer to Patent Document 1).

JP 2001-33704 A

  However, in the macro lens described in Patent Document 1, when the focusable range is further expanded, aberration fluctuations, particularly spherical aberration and coma aberration fluctuations increase, and the photographing magnification is close to the same magnification. When focused on a distance object, there was a problem that chromatic aberration of magnification deteriorated.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is from the infinite object focusing state to the short-distance object focusing state at the same magnification as the photographing magnification. It is to provide a macro lens with little aberration fluctuation.

In order to achieve the above object, a macro lens according to an aspect of the present invention includes, in order from the object side, a positive first group, a negative second group, a positive third group, and a negative fourth group. The first group and the fourth group do not move and the second group moves to the image side during focusing from an infinite object focused state to a short-distance object focused state at the same magnification. In the macro lens in which the third group moves toward the object side, the second group has a negative lens disposed closest to the object side and having a concave surface facing the image side, and an image side more than the negative lens And three or more lenses including a positive lens having a convex surface directed toward the object side, and satisfies the following conditional expression (1).
0.08 <ΣD _{G1L /L<0.181} (1)
Where ΣD _G1L is the total thickness of the lenses constituting the first group on the optical axis, and L is the image side surface of the most image side lens from the object side surface of the most object side lens on the optical axis. Is the length.

In order to achieve the above object, a macro lens according to an aspect of the present invention includes, in order from the object side, a positive first group, a negative second group, a positive third group, and a negative first group. The first group and the fourth group do not move and the second group is an image when focusing from the infinite object focusing state to the short distance object focusing state at the same magnification as the photographing magnification. In the macro lens in which the third group moves toward the object side, the first group includes four lenses, and all the lenses constituting the first group move toward the object side. The most object side lens among the lenses constituting the first group is a positive lens component, and the positive lens component is a positive lens alone or a cemented lens having positive power as a whole. Yes, the following conditional expression (2) is satisfied.
0.27 <( _{DG2-G3i-DG2 -G3s} ) / L <0.6 (2)
Where D _G2-G3i is the distance between the second group and the third group in the infinite object focusing state, and D _G2-G3s is the second group in the short-distance object focusing state at the same magnification as the shooting magnification. The distance from the third lens unit, L, is the length from the object-side surface of the most object-side lens on the optical axis to the image-side surface of the most image-side lens.

In order to achieve the above object, a macro lens according to an aspect of the present invention includes, in order from the object side, a positive first group, a negative second group, a positive third group, and a negative first group. The first group and the fourth group do not move and the second group is an image when focusing from the infinite object focusing state to the short distance object focusing state at the same magnification as the photographing magnification. In the macro lens in which the third group moves toward the object side, the first group includes four lenses, and all the lenses constituting the first group move toward the object side. The most object side lens among the lenses constituting the first group is a positive lens component, and the positive lens component is a positive lens alone or a cemented lens having positive power as a whole. And the following conditional expressions (1) and (2) are satisfied.
0.08 <ΣD _{G1L /L<0.181} (1)
0.27 <( _{DG2-G3i-DG2 -G3s} ) / L <0.6 (2)
Where ΣD _G1L is the total thickness of the lenses constituting the first group on the optical axis, and L is the image side surface of the most image side lens from the object side surface of the most object side lens on the optical axis. D _G2-G3i is the distance between the second group and the third group in the infinite object focusing state, and D _G2-G3s is the second group and the third in the infinite object focusing state. The distance from the group.

  According to the present invention, it is possible to provide a macro lens with little aberration variation from an infinite object focusing state to a short-distance object focusing state where the photographing magnification is equal.

2 is a cross-sectional view along the optical axis showing the configuration of the macro lens of the present invention according to Example 1, where (a) is an infinite object focusing state, (b) is an intermediate state (shooting magnification 0.5 times), ( c) shows a short-distance object in-focus state where the photographing magnification is equal to the magnification. An arrow between (a) and (b) represents the moving direction of each lens group when the observation state is changed from the infinite object focusing state to the intermediate state (shooting magnification 0.5 times). The arrows between (b) and (c) indicate the movement of each lens group when changing the observation state from an intermediate state (shooting magnification of 0.5 times) to a short-distance object in-focus state where the shooting magnification is the same magnification. It represents the direction. 2A and 2B are diagrams showing coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 1 is d, where FIG. 1A is an infinite object focusing state, and FIG. (5 times) and (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm). 2A and 2B are diagrams showing coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 1 is d, where FIG. 1A is an infinite object focusing state, and FIG. (5 times) and (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm). FIG. 4 is a cross-sectional view along the optical axis showing the configuration of the macro lens of the present invention according to Example 2, where (a) is an infinite object focusing state, (b) is an intermediate state (shooting magnification 0.5 times), ( c) shows a short-distance object in-focus state where the photographing magnification is equal to the magnification. An arrow between (a) and (b) represents the moving direction of each lens group when the observation state is changed from the infinite object focusing state to the intermediate state (shooting magnification 0.5 times). The arrows between (b) and (c) indicate the movement of each lens group when changing the observation state from an intermediate state (shooting magnification of 0.5 times) to a short-distance object in-focus state where the shooting magnification is the same magnification. It represents the direction. 5A and 5B are diagrams showing coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 4 is d, where FIG. 5A is an infinite object focusing state, and FIG. (5 times) and (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm). 5A and 5B are diagrams showing coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 4 is d, where FIG. 5A is an infinite object focusing state, and FIG. (5 times) and (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm). FIG. 4 is a cross-sectional view along the optical axis showing the configuration of the macro lens of the present invention according to Example 3, where (a) is an infinite object focusing state, (b) is an intermediate state (shooting magnification 0.5 times), ( c) shows a short-distance object in-focus state where the photographing magnification is equal to the magnification. An arrow between (a) and (b) represents the moving direction of each lens group when the observation state is changed from the infinite object focusing state to the intermediate state (shooting magnification 0.5 times). The arrows between (b) and (c) indicate the movement of each lens group when changing the observation state from an intermediate state (shooting magnification of 0.5 times) to a short-distance object in-focus state where the shooting magnification is the same magnification. It represents the direction. FIG. 8 is a diagram showing a coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 7 is d, where (a) is an infinite object focusing state, and (b) is an intermediate state (shooting magnification 0. 0). (5 times) and (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm). FIG. 8 is a diagram showing a coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 7 is d, where (a) is an infinite object focusing state, and (b) is an intermediate state (shooting magnification 0. 0). (5 times) and (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm). FIG. 6 is a cross-sectional view along the optical axis showing the configuration of the macro lens of the present invention according to Example 4, where (a) is an infinite object focusing state, (b) is an intermediate state (shooting magnification 0.5 times), ( c) shows a short-distance object in-focus state where the photographing magnification is equal to the magnification. An arrow between (a) and (b) represents the moving direction of each lens group when the observation state is changed from the infinite object focusing state to the intermediate state (shooting magnification 0.5 times). The arrows between (b) and (c) indicate the movement of each lens group when changing the observation state from an intermediate state (shooting magnification of 0.5 times) to a short-distance object in-focus state where the shooting magnification is the same magnification. It represents the direction. It is a figure which shows the coma aberration of 0.35 d when the real image height of the macro lens shown in FIG. 10 is set to d, (a) is an infinite object focusing state, (b) is an intermediate state (shooting magnification 0.0). (5 times) and (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm). It is a figure which shows the coma aberration of 0.35 d when the real image height of the macro lens shown in FIG. 10 is set to d, (a) is an infinite object focusing state, (b) is an intermediate state (shooting magnification 0.0). (5 times) and (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm). FIG. 6 is a cross-sectional view along the optical axis showing the configuration of a macro lens of the present invention according to Example 5, where (a) is an infinite object focusing state, (b) is an intermediate state (shooting magnification 0.5 times), ( c) shows a short-distance object in-focus state where the photographing magnification is equal to the magnification. An arrow between (a) and (b) represents the moving direction of each lens group when the observation state is changed from the infinite object focusing state to the intermediate state (shooting magnification 0.5 times). The arrows between (b) and (c) indicate the movement of each lens group when changing the observation state from an intermediate state (shooting magnification of 0.5 times) to a short-distance object in-focus state where the shooting magnification is the same magnification. It represents the direction. It is a figure which shows the coma aberration of 0.35d when the real image height of the macrolens shown in FIG. 13 is set to d, (a) is an infinite object focusing state, (b) is an intermediate state (shooting magnification 0.20). (5 times) and (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm). It is a figure which shows the coma aberration of 0.35d when the real image height of the macrolens shown in FIG. 13 is set to d, (a) is an infinite object focusing state, (b) is an intermediate state (shooting magnification 0.20). (5 times) and (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm). FIG. 6 is a cross-sectional view along the optical axis showing the configuration of a macro lens of the present invention according to Example 6, where (a) is an infinite object focusing state, (b) is an intermediate state (shooting magnification 0.5 times), ( c) shows a short-distance object in-focus state where the photographing magnification is equal to the magnification. An arrow between (a) and (b) represents the moving direction of each lens group when the observation state is changed from the infinite object focusing state to the intermediate state (shooting magnification 0.5 times). The arrows between (b) and (c) indicate the movement of each lens group when changing the observation state from an intermediate state (shooting magnification of 0.5 times) to a short-distance object in-focus state where the shooting magnification is the same magnification. It represents the direction. It is a figure which shows the coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 16 is set to d, (a) is an infinite object focusing state, (b) is an intermediate state (shooting magnification 0.0). (5 times) and (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm). It is a figure which shows the coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 16 is set to d, (a) is an infinite object focusing state, (b) is an intermediate state (shooting magnification 0.0). (5 times) and (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm).

  Prior to the description of the macro lens of this example, the operational effects of the configuration of the macro lens of this embodiment will be described. In addition, this invention is not limited by this embodiment. That is, in the description of the embodiments, many specific details are included for illustration, but those skilled in the art can add various variations and modifications to these details without departing from the scope of the present invention. It will be understood that this is not exceeded. Accordingly, the exemplary embodiments of the present invention described below are set forth without loss of generality or limitation to the claimed invention.

The macro lens according to the present embodiment includes, in order from the object side, a positive first group, a negative second group, a positive third group, and a negative fourth group. At the time of focusing to a short-distance object in-focus state where the photographing magnification is equal, the first group and the fourth group do not move, the second group moves to the image side, and the third group moves to the object side. In the moving macro lens, the second group is disposed on the most object side and has a negative lens with a concave surface facing the image side, and is disposed on the image side with respect to the negative lens and has a convex surface facing the object side. It consists of three or more lenses including a positive lens, and satisfies the following conditional expression (1).
0.08 <ΣD _{G1L /L<0.181} (1)
Where ΣD _G1L is the total thickness of the lenses constituting the first group on the optical axis, and L is the image side surface of the most image side lens from the object side surface of the most object side lens on the optical axis. Is the length.

Since the total thickness of the lenses constituting the first group on the optical axis falls within the range of the conditional expression (1), the macro lens of this embodiment is the second group that is the focus group. And the movable range of the third group is large, and aberrations can be corrected satisfactorily.
The second group includes a negative lens disposed closest to the object side and having a concave surface facing the image side, and a positive lens disposed closer to the image side than the negative lens and having a convex surface facing the object side. Since it is configured to include three or more lenses, it is possible to prevent the angle of the marginal ray from changing suddenly in the second group, that is, to change the angle of the marginal ray gently. it can. Therefore, the macro lens of the present embodiment can suppress fluctuations in coma and lateral chromatic aberration that occur during focusing.

  If the lower limit value of the conditional expression (1) is not reached, the lens rim is likely to be insufficient, which is not preferable. On the other hand, when the value exceeds the upper limit value, the ratio of the first group to the entire optical system increases, and the space for arranging the focus group decreases. Therefore, the powers of the second group and the third group must be increased, aberrations are likely to occur, and it becomes difficult to correct various aberrations. Further, if the space for arranging the focus group is reduced, it becomes difficult to achieve a sufficient focus action, and it becomes difficult to ensure the photographing magnification.

In addition, it is more preferable to configure so as to satisfy one of the following conditional expressions (1) ′ and (1) ″ instead of conditional expression (1).
0.124 <ΣD _{G1L /L<0.181} (1) ′
0.150 <ΣD _{G1L /L<0.166} (1) ”
Further, the lower limit value of the conditional expression (1) ′ may be set as the lower limit value of the conditional expression (1) ″, and the upper limit value or lower limit value of the conditional expression (1) ″ may be set as the conditional expressions (1) and (1). It may be an upper limit value or a lower limit value of '.

The macro lens according to the present embodiment includes, in order from the object side, a positive first group, a negative second group, a positive third group, and a negative fourth group. When focusing from a state to a short-distance object in-focus state where the photographing magnification is equal, the first group and the fourth group do not move, the second group moves to the image side, and the third group moves to the object side. In the macro lens that moves to the side, the first group includes four lenses, and all the lenses that form the first group have a convex surface facing the object side. Among the constituent lenses, the lens closest to the object side is a positive lens component, and the positive lens component is a positive lens alone or a cemented lens having positive power as a whole, and satisfies the following conditional expression (2) It is characterized by doing .
0.27 <( _{DG2-G3i-DG2 -G3s} ) / L <0.6 (2)
Where D _G2-G3i is the distance between the second group and the third group in the state of focusing on an object at infinity, D _G2-G3s
Is the distance between the second group and the third group in the short distance object in-focus state at the same magnification, and L is the distance from the object side surface of the most object side lens to the most image side lens on the optical axis. This is the length to the image side surface.

  By configuring the shape and arrangement of the lenses constituting the first group as described above, the macro lens of this embodiment can satisfactorily correct spherical aberration and coma. In addition, since the first group is composed of four lenses, the conditional expression (2) can be satisfied. Therefore, the macro lens of the present embodiment is movable between the second group and the third group which are focus groups. A sufficient range can be secured and aberrations can be corrected well. Therefore, in addition to configuring the first group in this way, the first group is configured to satisfy the conditional expression (2), thereby reducing the size of the first group, that is, reducing the size of the entire optical system and reducing coma aberration. It will be possible to correct well.

  If the lower limit of conditional expression (2) is not reached, it will be difficult to correct aberrations. On the other hand, if the upper limit is exceeded, the optical system becomes large.

Note that it is more preferable to configure so as to satisfy one of the following conditional expressions (2) ′ and (2) ″ instead of conditional expression (2).
0.27 <( _{DG2-G3i-DG2 -G3s} ) / L <0.5 (2) '
0.27 <( _{DG2-G3i-DG2 -G3s} ) / L <0.42 (2) "

The macro lens according to the present embodiment includes, in order from the object side, a positive first group, a negative second group, a positive third group, and a negative fourth group. When focusing from a state to a short-distance object in-focus state where the photographing magnification is equal, the first group and the fourth group do not move, the second group moves to the image side, and the third group moves to the object side. In the macro lens that moves to the side, the first group includes four lenses, and all the lenses that form the first group have a convex surface facing the object side. Among the constituting lenses, the lens closest to the object is a positive lens component, and the positive lens component is a positive lens alone or a cemented lens having positive power as a whole, and the following conditional expressions (1) and ( Satisfy 2).
0.08 <ΣD _{G1L /L<0.181} (1)
0.27 <( _{DG2-G3i-DG2 -G3s} ) / L <0.6 (2)
Where ΣD _G1L is the total thickness of the lenses constituting the first group on the optical axis, and L is the image side surface of the most image side lens from the object side surface of the most object side lens on the optical axis. D _G2-G3i is the distance between the second group and the third group in the infinite object focusing state, and D _G2-G3s is the second group and the third in the infinite object focusing state. The distance from the group.

  As described above, when the conditional expression (1) and the conditional expression (2), which are conditions for the configuration advantageous for correcting various aberrations, are satisfied, the macro lens of this embodiment corrects various aberrations satisfactorily. be able to.

  Further, in the macro lens of the present embodiment, the second group is disposed on the most object side and has a negative lens having a concave surface directed to the image side, and is disposed on the image side of the negative lens and on the object side. It is preferable to include three or more lenses including a positive lens having a convex surface.

  By configuring the second group in this way, it is possible to prevent the angle of the marginal ray from changing suddenly within the second group, that is, to change the angle of the marginal ray gently. Therefore, the macro lens according to the present embodiment can suppress fluctuations in coma and lateral chromatic aberration that occur during focusing.

In addition, the macro lens as a reference example of the present embodiment includes, in order from the object side, a positive first group, a negative second group, a positive third group, and a negative fourth group, and is infinite. At the time of focusing from a far object focused state to a close distance object focused state where the shooting magnification is the same magnification, the first group and the fourth group do not move, the second group moves to the image side, and the first group In the macro lens in which the third group moves toward the object side, the second group is disposed on the most object side and has a negative lens having a concave surface on the image side, and is disposed on the image side with respect to the negative lens. It comprises three or more lenses including a positive lens having a convex surface facing the side.

Since the second group is configured in this way, the macro lens as a reference example of the present embodiment can prevent the angle of the marginal ray from changing abruptly within the second group, that is, the marginal. The angle of the light beam can be changed gently. Therefore, the macro lens according to the present embodiment can suppress fluctuations in coma and lateral chromatic aberration that occur during focusing.

Moreover, it is preferable that the macro lens of this embodiment satisfies the following conditional expression (3).
0.4 <Ls _G2n <2 (3)
Where Ls _G2n = (r _G2nf + r _G2nb ) / (r _G2nf −r _G2nb ), r _G2nf is the radius of curvature of the object side surface of the negative lens included in the second group, and r _G2nb is the second radius This is the radius of curvature of the image side surface of the negative lens included in the group.

  Conditional expression (3) forms the second group by three or more lenses including a negative lens having a concave surface facing the image side and a positive lens having a convex surface facing the object side disposed on the image side of the negative lens. In this case, the conditional expression defines the shape of the negative lens.

  If the lower limit value of the conditional expression (3) is not reached, the height of off-axis marginal rays of the positive lens having the convex surface facing the object side arranged on the image side of the negative lens becomes high, and coma becomes large. . On the other hand, if the upper limit value is exceeded, the amount of change in the angle of the on-axis marginal ray within the negative lens increases, and the spherical aberration increases.

In addition, it is more preferable to configure so as to satisfy one of the following conditional expressions (3) ′ and (3) ″ instead of conditional expression (3).
0.8 <Ls _G2n <1.4 (3) '
0.9 <Ls _G2n <1.4 (3) "
The upper limit value or lower limit value of conditional expression (3) ′ may be set as the upper limit value or lower limit value of conditional expression (3), and the lower limit value of conditional expression (3) ″ is set as the lower limit value of conditional expression (3). It is good as a value.

Moreover, it is preferable that the macro lens of this embodiment satisfies the following conditional expression (4).
−33 <Ls _G2p <−1 (4)
Where Ls _G2p = (r _G2pf + r _G2pb ) / (r _G2pf −r _G2pb ), r _G2pf is the radius of curvature of the object side surface of the positive lens included in the second group, and r _G2nb is the second radius It is a radius of curvature of the image side surface of the positive lens included in the group.

  Conditional expression (4) is a negative lens in which the second lens unit is disposed closest to the object side and has a concave surface facing the image side, and a positive lens that is disposed closer to the image side than the negative lens and has a convex surface facing the object side. This is a conditional expression that defines the shape of the positive lens when it is constituted by three or more lenses including the lens.

  If the lower limit value of the conditional expression (4) is not reached, the amount of change in the angle of the on-axis marginal ray within the negative lens increases, and the spherical aberration increases. On the other hand, if the value exceeds the upper limit, the height of off-axis marginal rays of the positive lens with the convex surface facing the object side arranged on the image side of the negative lens increases, and the lateral chromatic aberration increases.

Note that it is more preferable that the following conditional expression (4) ′ is satisfied instead of conditional expression (4).
−7 <Ls _G2p <−1 (4) ′

In the macro lens of the present embodiment, it is preferable that the lens disposed closest to the object side in the first group is a positive lens and satisfies the following conditional expression (5).
0.05 < _DG2F / _DG3F <0.710 (5)
However, D _G2F is the movement amount during focusing of the second group, and D _G3F is the movement amount during focusing of the third group.

  Conditional expression (5) is a conditional expression that defines the amount of movement during focusing of the second group and the third group. If configured so as to satisfy this conditional expression, the macro lens of the present embodiment corrects aberrations well in all states from an infinite object focusing state to a short-distance object focusing state where the shooting magnification is the same magnification. can do.

  If the lower limit value of conditional expression (5) is not reached, it will be difficult to satisfactorily correct aberration fluctuations, particularly off-axis aberration fluctuations in the short-distance object in-focus state where the photographing magnification is the same magnification. On the other hand, if the upper limit value is exceeded, fluctuations in coma will become large.

In addition, it is more preferable to configure so as to satisfy one of the following conditional expressions (5) ′ and (5) ″ instead of conditional expression (5).
0.10 < _DG2F / _DG3F <0.710 (5) '
0.15 < _DG2F / _DG3F <0.665 (5) "
Further, the lower limit value of the conditional expression (5) ′ may be set as the lower limit value of the conditional expression (5) ″, and the upper limit value or the lower limit value of the conditional expression (5) ″ may be set as the conditional expressions (5) and (5). It may be an upper limit value or a lower limit value of '.

Moreover, it is preferable that the macro lens of this embodiment satisfies the following conditional expression (6).
0.2 <| _fG3 / _fG2 | <2.0 (6)
Here, f _G3 is the focal length of the third group, and f _G2 is the focal length of the second group.

  Conditional expression (6) is a conditional expression that defines the refractive power ratio between the second group and the third group. If configured so as to satisfy this conditional expression, the macro lens of the present embodiment corrects aberrations well in all states from an infinite object focusing state to a short-distance object focusing state where the shooting magnification is the same magnification. can do.

  If the lower limit value of conditional expression (6) is not reached, the refractive power of the third group becomes strong, and it becomes difficult to satisfactorily correct off-axis aberrations in the short distance object in-focus state where the photographing magnification is equal to the magnification. End up. On the other hand, if the upper limit is exceeded, the refractive power of the third group becomes weak, the amount of movement during focusing increases, and the optical system becomes large.

In addition, it is more preferable to configure so as to satisfy one of the following conditional expressions (6) ′ and (6) ″ instead of conditional expression (6).
0.4 <| f _G3 / f _G2 | <1.6 (6) ′
0.8 <| _fG3 / _fG2 | <1.1 (6) "
Further, the upper limit value or lower limit value of conditional expression (6) ′ may be used as the upper limit value or lower limit value of conditional expression (6), (6) ″, or the upper limit value or lower limit value of conditional expression (6) ″ may be Conditional expressions (6) and (6) ′ may be the upper limit value or the lower limit value.

In the macro lens of the present embodiment, it is preferable that the fourth group includes at least two lenses and satisfies the following conditional expression (7).
0.1 <(D _G4Amax + bf) / f _i <0.7 (7)
However, _DG4Amax is the longest length of the air space between the lenses constituting the fourth group on the optical axis, bf is the back focus, and f _i is the focal length in the infinite object focusing state.

  Conditional expression (7) is a conditional expression that defines the air spacing and back focus between the lenses constituting the fourth lens group.

  If the lower limit of conditional expression (7) is not reached, the optical system can be reduced in size, but in all states from the infinite object focusing state to the short distance object focusing state at the same magnification as the photographing magnification, the fourth group The oblique incidence angle of off-axis marginal rays emitted from the lens becomes so tight that the coma aberration deteriorates. On the other hand, if the upper limit is exceeded, the oblique incidence angle of off-axis marginal rays becomes loose and coma can be corrected, but the optical system becomes large.

In addition, it is more preferable to configure so as to satisfy one of the following conditional expressions (7) ′ and (7) ″ instead of conditional expression (7).
0.22 <(D _G4Amax + bf) / f _i <0.5 (7) ′
0.24 <(D _G4Amax + bf) / f _i <0.37 (7) "
Further, the upper limit value or lower limit value of conditional expression (7) ′ may be used as the upper limit value or lower limit value of conditional expression (7), (7) ″, or the upper limit value or lower limit value of conditional expression (7) ″ may be Conditional expressions (7) and (7) ′ may be the upper limit value or the lower limit value.

In the macro lens of the present embodiment, it is preferable that the fourth group includes at least two lenses and satisfies the following conditional expression (8).
0.08 < _DG4Amax / f <0.3 (8)
However, _DG4Amax is the longest length of the air gap between the lenses constituting the fourth group on the optical axis, and f is the focal length of the entire system in the infinite object focused state.

Conditional expression (8) is a conditional expression that regulates the relationship between the air gap between the lenses constituting the fourth group and the focal length of the entire macro lens system. When this conditional expression (8) is satisfied, astigmatism can be corrected while preventing the optical system from becoming large .

  If the lower limit of conditional expression (8) is not reached, the optical system can be miniaturized, but astigmatism cannot be corrected well. On the other hand, if the value exceeds the upper limit value, astigmatism can be corrected well, but the optical system is enlarged, and the number of members used increases, which is not preferable.

In addition, it is more preferable to configure so as to satisfy one of the following conditional expressions (8) ′ and (8) ″ instead of conditional expression (8).
0.09 < _DG4Amax / f <0.2 (8) '
0.10 < _DG4Amax / f <1.4 (8) "
Further, the upper limit value or lower limit value of the conditional expression (8) ′ may be set as the upper limit value or lower limit value of the conditional expression (8), (8) ″, or the upper limit value or lower limit value of the conditional expression (8) ″ may be Conditional expressions (8) and (8) ′ may be the upper limit value or the lower limit value.

Moreover, it is preferable that the macro lens of this embodiment satisfies the following conditional expression (9).
0.5 <D _G4Amax / BF <1.8 (9)
However, _DG4Amax is the longest length of the air space between the lenses constituting the fourth group on the optical axis, and BF is the back focus.

  Conditional expression (9) is a conditional expression that defines the relationship between the air gap between the lenses constituting the fourth group and the back focus. When this conditional expression (9) is satisfied, astigmatism and coma can be corrected well, and an increase in size can be prevented.

  If the lower limit value of conditional expression (9) is not reached, the oblique incident angle of off-axis marginal rays becomes tight and coma becomes worse. On the other hand, if the value exceeds the upper limit value, astigmatism can be corrected, the optical system becomes larger, and the number of members used increases, which is not preferable.

In the macro lens of the present embodiment, the first group includes a positive lens in order from the object side, a cemented lens including a negative lens and a positive lens in order from the object side, and a positive lens. It is preferable to satisfy conditional expression (10).
−0.33 <Ls _G1p2 −Ls _G1p3 <10 (10)
However, _LsG1p2 = ( _rG1p2f + _rG1p2b ) / ( _{rG1p2f− rG1p2b} ), _LsG1p3 = ( _rG1p3f + _rG1p3b ) / ( _{rG1p3f− rG1p3b} ), and the _rG1p2f is included in the _rG1p2f The radius of curvature of the object side surface of the second positive lens from the object side, r _G1p2b is the radius of curvature of the image side surface of the second positive lens included in the first group, and r _G1p3f is the first radius of curvature. The radius of curvature of the object side surface of the third positive lens included in the group, r _G1p3b is the radius of curvature of the image side surface of the third positive lens included in the first group.

  If such a configuration of the first group is satisfied and the included lens satisfies the conditional expression (10), it is possible to satisfactorily correct spherical aberration and coma aberration that are difficult in a bright telephoto optical system. .

  If the lower limit value of conditional expression (10) is not reached, the height of off-axis marginal rays incident on the third positive lens from the object side becomes high, and coma aberration and lateral chromatic aberration are deteriorated. On the other hand, if the value exceeds the upper limit value, the amount of change in the angle of the on-axis marginal ray increases, and the spherical aberration becomes worse.

In addition, it is more preferable to configure so as to satisfy one of the following conditional expressions (10) ′ and (10) ″ instead of conditional expression (10).
−0.33 <Ls _G1p2 −Ls _G1p3 <5.0 (10) ′
−0.25 <Ls _G1p2 −Ls _G1p3 <4.4 (10) ”
Further, the upper limit value of the conditional expression (10) ′ may be set as the upper limit value of the conditional expression (10) ″, and the upper limit value or the lower limit value of the conditional expression (10) ″ is set as the conditional expressions (10) and (10). It may be an upper limit value or a lower limit value of '.

Moreover, it is preferable that the macro lens of this embodiment satisfies the following conditional expression (11).
0.34 < _fG1 / f <0.57 (11)
Here, f _G1 is the focal length of the first group, and f is the focal length of the entire system in the state of focusing on an object at infinity.

  Conditional expression (11) defines the relationship between the focal length of the first group and the focal length of the entire macro lens system. When this conditional expression (11) is satisfied, the enlargement of the optical system can be prevented and various aberrations (particularly spherical aberration and coma aberration) can be corrected.

  If the lower limit value of the conditional expression (11) is not reached, the focal length of the first group becomes large, so that the optical system can be miniaturized, but this causes various aberrations (especially spherical aberration and axial chromatic aberration) to occur strongly. End up. On the other hand, if the value exceeds the upper limit value, the positive power of the first lens group becomes weak. Therefore, it is necessary to increase the absolute value of the radius of curvature of the lenses constituting the optical system. The system becomes larger.

Moreover, it is preferable that the macro lens of this embodiment satisfies the following conditional expressions (12) and (13).
70 <νd _G1pa <95 (12)
1.8 <n _G1na <2.1 (13)
Where νd _G1pa is the average Abbe number for the d-line of lenses having a positive refractive power among the lenses constituting the first group, and n _G1na is the negative refractive power of the lenses constituting the first group. This is the average value of the refractive index of the lens.

  Conditional expressions (12) and (13) are conditional expressions that define the Abbe number of the positive lens and the refractive index of the negative lens constituting the first group. When the conditional expressions (12) and (13) are satisfied, the lateral chromatic aberration and spherical aberration can be corrected satisfactorily.

  If the lower limit of conditional expression (12) is not reached, the lateral chromatic aberration cannot be corrected satisfactorily. On the other hand, if the upper limit value is exceeded, there is no practically usable glass material. If the lower limit of conditional expression (13) is not reached, spherical aberration cannot be corrected satisfactorily. On the other hand, if the upper limit is exceeded, there is no realistic glass material.

  Hereinafter, examples of the macro lens of this example will be described with reference to the drawings.

In the optical system cross-sectional views r ₁ , r ₂ ,... And d ₁ , d ₂ ,..., The numbers indicated as subscripts correspond to the surface numbers 1, 2,. doing.

  In the numerical data, s is the surface number, r is the radius of curvature of each surface, d is the surface spacing, nd is the refractive index at the d-line (wavelength 587.56 nm), and νd is the Abbe number at the d-line. Yes.

  Hereinafter, the macro lens according to Example 1 will be described in detail with reference to FIGS.

  1A and 1B are cross-sectional views along the optical axis showing the configuration of the macro lens according to the present embodiment, where FIG. 1A is an infinite object focusing state, and FIG. 1B is an intermediate state (shooting magnification 0.5 times). ) And (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. An arrow between (a) and (b) represents the moving direction of each lens group when the observation state is changed from the infinite object focusing state to the intermediate state (shooting magnification 0.5 times). The arrows between (b) and (c) indicate the movement of each lens group when changing the observation state from an intermediate state (shooting magnification of 0.5 times) to a short-distance object in-focus state where the shooting magnification is the same magnification. It represents the direction. 2A and 2B are diagrams showing coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 1 is d, where FIG. 2A is an infinite object focusing state, and FIG. 2B is an intermediate state ( (Capturing magnification 0.5 times) and (c) respectively show a short-distance object focusing state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm). 3A and 3B are diagrams showing coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 1 is d, where FIG. 3A is an infinite object focusing state, and FIG. 3B is an intermediate state ( (Capturing magnification 0.5 times) and (c) respectively show a short-distance object focusing state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm).

The macro lens of the present embodiment is arranged in order from the object side on the optical axis Lc, a positive first group G ₁ , a negative second group G ₂ , a positive third group G ₃ , and a negative fourth group G _4. Is arranged. Note that an aperture stop S configured integrally with the third group G ₃ is disposed between the third group G ₃ and the fourth group G ₄ . Further, on the image side of the fourth group G ₄ is composed of, in order from the object side, CCD cover glass CG, and a CCD having an imaging surface IM are arranged. The CCD cover glass CG is not always essential.

The first group G ₁ includes, in order from the object side, a lens L ₁₁ that is a biconvex lens, a lens L ₁₂ that is a meniscus lens having a negative refractive power with a convex surface facing the object side in order from the object side, and a convex surface on the object side. is composed of a cemented lens consisting of a lens L ₁₃ Metropolitan is a meniscus lens having a positive refractive power toward a lens L ₁₄ is a meniscus lens having a positive refractive power and a convex surface facing the object side.

The second group G ₂ has, in order from the object side, a lens L ₂₁ that is a biconcave lens, a lens L ₂₂ that is a meniscus lens having a positive refractive power with the convex surface facing the object side, and a convex surface facing the object side. The lens L ₂₃ is a meniscus lens having negative refractive power, and the lens L ₂₄ is a meniscus lens having positive refractive power with a convex surface facing the object side.

The third group G ₃ is a lens L ₃₁ that is a biconvex lens in order from the object side, a lens L ₃₂ that is a biconvex lens in order from the object side, and a meniscus lens having negative refractive power with a concave surface facing the object side. It is composed of a cemented lens consisting of a lens L ₃₃ Prefecture.

The fourth group G ₄ includes, in order from the object side, a lens L ₄₁ that is a meniscus lens having a negative refractive power with a convex surface facing the object side, a lens L ₄₂ that is a biconcave lens, and a biconvex lens in order from the object side. It is composed of a cemented lens consisting of a lens L ₄₃ Prefecture.

Further, when focusing from infinity focus to a close object in-focus condition to be photographed magnification magnification, the first group G ₁ is not moved along the optical axis Lc. The second group G ₂ moves to the image side on the optical axis Lc while widening the interval with the first group G ₁ . The third group G ₃ moves toward the object side on the optical axis Lc while narrowing the interval with the second group G ₂ . The fourth group G ₄ does not move on the optical axis Lc. The aperture stop S, because it is configured third group G ₃ integrally with and moves together with the third group G _3.

  Next, numerical data relating to the lens constituting the macro lens of the present embodiment will be shown.

Numerical data 1
Unit mm
Surface data Surface number Curvature radius Surface spacing Refractive index Abbe number s r d nd νd
1 92.229 5.50 1.48749 70.23
2 -461.293 0.20
3 61.971 1.00 1.80610 40.92
4 38.203 10.50 1.49700 81.54
5 6839258.278 0.15
6 63.911 4.31 1.49700 81.54
7 365.835 D7
8 -480.113 3.00 1.69680 55.53
9 31.557 1.20
10 25.727 5.00 1.61800 63.33
11 52.496 2.80
12 137.261 3.00 1.69680 55.53
13 25.924 2.00
14 31.098 3.00 1.78472 25.68
15 46.304 D15
16 (Aperture) ∞ 0.20
17 75.971 5.03 1.49700 81.54
18 -209.540 0.20
19 129.427 3.00 1.59282 68.63
20 -46.055 1.00 1.80518 25.42
21 -108.106 D21
22 62.508 1.40 1.48749 70.23
23 23.538 7.40
24 -71.022 1.40 1.62588 35.70
25 32.488 4.00 1.85026 32.27
26 -96.400 D26
27 ∞ 4.2 1.51633 64.14
28 ∞ D28
29 (Image plane) ∞

Various data
Magnification at infinity -0.5 -1
Focal length 150.11 109.12 81.24
F number 2.83 1.85 1.30
Angle of view (2ω) 8.33 4.76 3.68
Image height 11.15 11.15 11.15
Total length 178.64 178.64 178.64
Back focus (in air) 44.08 44.08 44.08

Plane interval Shooting magnification Infinite -0.5 -1
D7 7.48 11.27 16.76
D15 59.91 27.03 4.20
D21 1.87 30.97 48.30
D26 40.00 40.00 40.00
D28 1.31 1.32 1.32

Lens group data Group Start surface Focal length
1 1 58.85
2 8 -40.02
3 17 62.52
4 22 -214.57

Data related to the above conditional expression (1): 0.08 <ΣD _G1L /L<0.181 : 0.16098
Formula (2): 0.27 <( _{DG2 -G3i-DG2-G3s} ) / L <0.6: 0.413
Formula (3): 0.4 <Ls _G2n <2 : 0.876
Formula (4): −33 <Ls _G2p <−1 : -2.922
Formula (5): 0.05 <D _G2F / D _G3F <0.710 : 0.199
Formula (6): 0.2 <| f _G3 / f _G2 | <2.0 : 1.56
Formula (7): 0.1 <(D _G4Amax + bf) / f _i <0.7 : 0.3429
Formula (8): 0.08 <D _G4Amax /f<0.3 : −
Formula (9): 0.5 <D _G4Amax / BF <1.8 : −
Formula (10): −0.33 <Ls _G1p2 −Ls _G1p3 <10 : 0.423
Formula (11): 0.34 <f _G1 /f<0.57 : 0.392
Formula (12): 70 <νd _G1pa <95 : 77.77
Formula (13): 1.8 <n _G1na <2.1 : 1.8061

  The macro lens according to Example 2 will be described in detail below with reference to FIGS.

  4A and 4B are cross-sectional views along the optical axis showing the configuration of the macro lens according to the present embodiment, where FIG. 4A is an infinite object focusing state, and FIG. 4B is an intermediate state (shooting magnification 0.5 times). ) And (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. An arrow between (a) and (b) represents the moving direction of each lens group when the observation state is changed from the infinite object focusing state to the intermediate state (shooting magnification 0.5 times). The arrows between (b) and (c) indicate the movement of each lens group when changing the observation state from an intermediate state (shooting magnification of 0.5 times) to a short-distance object in-focus state where the shooting magnification is the same magnification. It represents the direction. 5A and 5B are diagrams showing coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 4 is d, where FIG. 5A is an infinite object focusing state, and FIG. 5B is an intermediate state ( (Capturing magnification 0.5 times) and (c) respectively show a short-distance object focusing state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm). 6A and 6B are diagrams showing coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 4 is d, where FIG. 6A is an infinite object focusing state, and FIG. 6B is an intermediate state ( (Capturing magnification 0.5 times) and (c) respectively show a short-distance object focusing state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm).

The macro lens of the present embodiment is arranged in order from the object side on the optical axis Lc, a positive first group G ₁ , a negative second group G ₂ , a positive third group G ₃ , and a negative fourth group G _4. Is arranged. Note that an aperture stop S configured integrally with the third group G ₃ is disposed between the third group G ₃ and the fourth group G ₄ . Further, on the image side of the fourth group G ₄ is composed of, in order from the object side, CCD cover glass CG, and a CCD having an imaging surface IM are arranged.

The first group G ₁ includes, in order from the object side, a lens L ₁₁ that is a biconvex lens, a lens L ₁₂ that is a meniscus lens having a negative refractive power with a convex surface facing the object side in order from the object side, and a convex surface on the object side. is composed of a cemented lens consisting of a lens L ₁₃ Metropolitan is a meniscus lens having a positive refractive power toward a lens L ₁₄ is a meniscus lens having a positive refractive power and a convex surface facing the object side.

The second group G ₂ includes, in order from the object side, and L ₂₁ is a meniscus lens having negative refractive power with a convex surface facing the object side, is a meniscus lens having a positive refractive power and a convex surface facing the object side The lens L ₂₂ includes a lens L ₂₃ that is a meniscus lens having a negative refractive power with a convex surface facing the object side, and a lens L ₂₄ that is a meniscus lens having a positive refractive power having a convex surface facing the object side. Has been.

The third group G ₃ includes, in order from the object side, a lens L ₃₁ that is a biconvex lens, and a cemented lens that includes a lens L ₃₂ that is a biconvex lens and a lens L ₃₃ that is a biconcave lens in order from the object side. Yes.

The fourth group G ₄ includes, in order from the object side, a lens L ₄₁ that is a meniscus lens having a negative refractive power with a convex surface facing the object side, a lens L ₄₂ that is a biconcave lens, and a biconvex lens in order from the object side. It is composed of a cemented lens consisting of a lens L ₄₃ Prefecture.

Further, when focusing from infinity focus to a close object in-focus condition to be photographed magnification magnification, the first group G ₁ is not moved along the optical axis Lc. The second group G ₂ moves to the image side on the optical axis Lc while widening the interval with the first group G ₁ . The third group G ₃ moves toward the object side on the optical axis Lc while narrowing the interval with the second group G ₂ . The fourth group G ₄ does not move on the optical axis Lc. The aperture stop S, because it is configured third group G ₃ integrally with and moves together with the third group G _3.

  Next, numerical data relating to the lens constituting the macro lens of the present embodiment will be shown.

Numerical data 2
Unit mm
Surface data Surface number Curvature radius Surface spacing Refractive index Abbe number s r d nd νd
1 108.929 6.00 1.63854 55.38
2 -652.454 0.20
3 90.898 2.50 1.88300 40.76
4 39.036 9.61 1.49700 81.54
5 352.031 0.15
6 48.770 6.48 1.49700 81.54
7 263.776 D7
8 295.813 3.00 1.69680 55.53
9 42.229 1.20
10 27.331 4.00 1.61800 63.33
11 36.490 4.80
12 61.411 3.00 1.69680 55.53
13 25.718 2.00
14 31.074 3.00 1.78472 25.68
15 47.054 D15
16 (Aperture) ∞ 0.20
17 75.402 5.39 1.88300 40.76
18 -128.870 0.20
19 49.666 3.80 1.59282 68.63
20 -80.294 0.77 1.80518 25.42
21 73.400 D21
22 161.563 1.40 1.48749 70.23
23 21.321 17.69
24 -70.432 1.40 1.62588 35.70
25 30.096 4.46 1.85026 32.27
26 -96.400 D26
27 ∞ 4.2 1.51633 64.14
28 ∞ D28
29 (Image plane) ∞

Various data
Magnification at infinity -0.5 -1
Focal length 149.95 99.65 72.16
F number 2.83 1.71 1.12
Angle of view (2ω) 8.35 4.74 3.45
Image height 11.15 11.15 11.15
Total length 169.65 169.65 169.65
Back focus (in air) 20.09 20.09 20.09

Plane interval Shooting magnification Infinite -0.5 -1
D7 5.61 12.79 23.81
D15 59.03 30.16 4.89
D21 3.66 25.35 39.60
D26 16.00 16.00 16.00
D28 1.32 1.32 1.32

Lens group data Group Start surface Focal length
1 1 75.40
2 8 -67.93
3 17 56.13
4 22 -112.04

Data related to the above conditional expression
   Formula (1): 0.08 <ΣD_G1L/L<0.181  : 0.16674
   Formula (2): 0.27 <(D_G2-G3i-D_G2-G3s) / L <0.6: 0.362
   Formula (3): 0.4 <Ls_G2n<2         : 1.333
   Formula (4): −33 <Ls_G2p<-1        : -6.968
   Formula (5): 0.05 <D_G2F/ D_G3F<0.710   : 0.506
   Formula (6): 0.2 <| f_G3/ F_G2| <2.0    : 0.82
   Formula (7): 0.1 <(D_G4Amax+ Bf) / f_i<0.7 : 0.251
   Formula (8): 0.08 <D_G4Amax/F<0.3     : 0.11
   Formula (9): 0.5 <D_G4Amax/BF<1.8     : 0.88
  Formula (10): -0.33 <Ls_G1p2-Ls_G1p3<10   : -0.2424
  Formula (11): 0.34 <f_G1/F<0.57    : 0.502
  Formula (12): 70 <νd_G1pa<95         : 72.82
  Formula (13): 1.8 <n_G1na<2.1        : 1.883

  Hereinafter, the macro lens according to Example 3 will be described in detail with reference to FIGS.

  FIG. 7 is a cross-sectional view along the optical axis showing the configuration of the macro lens according to the present embodiment, where (a) is an infinite object focused state, and (b) is an intermediate state (shooting magnification 0.5 times). ) And (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. An arrow between (a) and (b) represents the moving direction of each lens group when the observation state is changed from the infinite object focusing state to the intermediate state (shooting magnification 0.5 times). The arrows between (b) and (c) indicate the movement of each lens group when changing the observation state from an intermediate state (shooting magnification of 0.5 times) to a short-distance object in-focus state where the shooting magnification is the same magnification. It represents the direction. 8A and 8B are diagrams showing coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 7 is d, where FIG. 8A is an infinite object focusing state, and FIG. 8B is an intermediate state ( (Capturing magnification 0.5 times) and (c) respectively show a short-distance object focusing state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm). 9A and 9B are diagrams showing coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 7 is d, where FIG. 9A is an infinite object focusing state, and FIG. 9B is an intermediate state ( (Capturing magnification 0.5 times) and (c) respectively show a short-distance object focusing state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm).

The macro lens of the present embodiment is arranged in order from the object side on the optical axis Lc, a positive first group G ₁ , a negative second group G ₂ , a positive third group G ₃ , and a negative fourth group G _4. Is arranged. Note that an aperture stop S configured integrally with the third group G ₃ is disposed between the third group G ₃ and the fourth group G ₄ . Further, on the image side of the fourth group G ₄ is composed of, in order from the object side, CCD cover glass CG, and a CCD having an imaging surface IM are arranged.

The first group G ₁ includes, in order from the object side, a lens L ₁₁ that is a biconvex lens, a lens L ₁₂ that is a meniscus lens having a negative refractive power with a convex surface facing the object side in order from the object side, and a convex surface on the object side. is composed of a cemented lens consisting of a lens L ₁₃ Metropolitan is a meniscus lens having a positive refractive power toward a lens L ₁₄ is a meniscus lens having a positive refractive power and a convex surface facing the object side.

The second group G ₂ has, in order from the object side, a lens L ₂₁ that is a biconcave lens, a lens L ₂₂ that is a meniscus lens having a positive refractive power with the convex surface facing the object side, and a convex surface facing the object side. The lens L ₂₃ is a meniscus lens having negative refractive power, and the lens L ₂₄ is a meniscus lens having positive refractive power with a convex surface facing the object side.

The third group G ₃ is a lens L ₃₁ that is a biconvex lens in order from the object side, a lens L ₃₂ that is a biconvex lens in order from the object side, and a meniscus lens having negative refractive power with a concave surface facing the object side. It is composed of a cemented lens consisting of a lens L ₃₃ Prefecture.

The fourth group G ₄ includes, in order from the object side, a lens L ₄₁ that is a biconcave lens, and a cemented lens that includes a lens L ₄₂ that is a biconcave lens and a lens L ₄₃ that is a biconvex lens in order from the object side. Yes.

Further, when focusing from infinity focus to a close object in-focus condition to be photographed magnification magnification, the first group G ₁ is not moved along the optical axis Lc. The second group G ₂ moves to the image side on the optical axis Lc while widening the interval with the first group G ₁ . The third group G ₃ moves toward the object side on the optical axis Lc while narrowing the interval with the second group G ₂ . The fourth group G ₄ does not move on the optical axis Lc. The aperture stop S, because it is configured third group G ₃ integrally with and moves together with the third group G _3.

  Next, numerical data relating to the lens constituting the macro lens of the present embodiment will be shown.

Numerical data 3
Unit mm
Surface data Surface number Curvature radius Surface spacing Refractive index Abbe number s r d nd νd
1 81.334 5.70 1.49700 81.54
2 -661.864 0.20
3 67.061 2.61 1.80610 40.92
4 35.104 10.84 1.48749 70.23
5 395.153 0.15
6 62.461 4.26 1.49700 81.54
7 418.229 D7
8 -1688.273 3.00 1.69680 55.53
9 42.023 1.20
10 24.113 4.00 1.61800 63.33
11 33.143 2.80
12 47.397 3.00 1.69680 55.53
13 21.697 2.00
14 26.293 3.00 1.78472 25.68
15 35.810 D15
16 (Aperture) ∞ 0.20
17 65.701 5.87 1.49700 81.54
18 -129.399 0.20
19 64.240 5.02 1.59282 68.63
20 -46.528 1.00 1.80518 25.42
21 -165.532 D21
22 -16432.853 1.40 1.48749 70.23
23 19.100 16.16
24 -88.286 1.40 1.62588 35.70
25 21.549 5.14 1.85026 32.27
26 -96.400 D26
27 ∞ 4.2 1.51633 64.14
28 ∞ D28
29 (Image plane) ∞

Various data
Magnification at infinity -0.5 -1
Focal length 149.96 106.72 78.48
F number 2.83 1.64 0.88
Angle of view (2ω) 8.37 4.32 2.64
Image height 11.15 11.15 11.15
Total length 160.63 160.63 160.63
Back focus (in air) 15.07 15.07 15.07

Plane interval Shooting magnification Infinite -0.5 -1
D7 6.84 14.19 26.91
D15 55.38 28.26 4.92
D21 4.19 23.96 34.58
D26 11.00 11.00 11.00
D28 1.30 1.30 1.30

Lens group data Group Start surface Focal length
1 1 67.33
2 8 -54.58
3 17 48.89
4 22 -136.94

Data related to the above conditional expression (1): 0.08 <ΣD _G1L /L<0.181 : 0.16325
Formula (2): 0.27 <( _{DG2 -G3i-DG2-G3s} ) / L <0.6: 0.346
Formula (3): 0.4 <Ls _G2n <2 : 0.951
Formula (4): −33 <Ls _G2p <−1 : -6.3401
Formula (5): 0.05 <D _G2F / D _G3F <0.710 : 0.660
Formula (6): 0.2 <| f _G3 / f _G2 | <2.0 : 0.89
Formula (7): 0.1 <(D _G4Amax + bf) / f _i <0.7 : 0.208
Formula (8): 0.08 <D _G4Amax /f<0.3 : 0.107
Formula (9): 0.5 <D _G4Amax /BF<1.8 : 1.07
Formula (10): −0.33 <Ls _G1p2 −Ls _G1p3 <10 : -0.05766
Formula (11): 0.34 <f _G1 /f<0.57 : 0.448
Formula (12): 70 <νd _G1pa <95 : 77.77
Formula (13): 1.8 <n _G1na <2.1 : 1.8061

  The macro lens according to Example 4 will be described in detail below with reference to FIGS.

  10A and 10B are cross-sectional views along the optical axis showing the configuration of the macro lens according to the present embodiment, where FIG. 10A is an infinite object focusing state, and FIG. 10B is an intermediate state (shooting magnification 0.5 times). ) And (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. An arrow between (a) and (b) represents the moving direction of each lens group when the observation state is changed from the infinite object focusing state to the intermediate state (shooting magnification 0.5 times). The arrows between (b) and (c) indicate the movement of each lens group when changing the observation state from an intermediate state (shooting magnification of 0.5 times) to a short-distance object in-focus state where the shooting magnification is the same magnification. It represents the direction. 11A and 11B are diagrams showing coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 10 is d, where FIG. 11A is an infinite object focusing state, and FIG. 11B is an intermediate state ( (Capturing magnification 0.5 times) and (c) respectively show a short-distance object focusing state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm). 12A and 12B are diagrams showing coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 10 is d, where FIG. 12A is an infinite object focusing state, and FIG. 12B is an intermediate state ( (Capturing magnification 0.5 times) and (c) respectively show a short-distance object focusing state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm).

The macro lens of the present embodiment is arranged in order from the object side on the optical axis Lc, a positive first group G ₁ , a negative second group G ₂ , a positive third group G ₃ , and a negative fourth group G _4. Is arranged. Note that an aperture stop S configured integrally with the third group G ₃ is disposed between the third group G ₃ and the fourth group G ₄ . Further, on the image side of the fourth group G ₄ is composed of, in order from the object side, CCD cover glass CG, and a CCD having an imaging surface IM are arranged.

The first group G ₁ includes a lens L ₁₁ that is a biconvex lens in order from the object side, a lens L ₁₂ that is a meniscus lens having a negative refractive power with a convex surface facing the object side in order from the object side, and a biconvex lens. a cemented lens consisting of a lens L ₁₃ Prefecture, is constituted by the lens L ₁₄ is a meniscus lens having a positive refractive power and a convex surface facing the object side.

The second group G ₂ includes, in order from the object side, a lens L ₂₁ that is a biconcave lens, a lens L ₂₂ that is a meniscus lens having a positive refractive power with a convex surface facing the object side, and a lens L ₂₃ that is a biconcave lens. And a lens L ₂₄ which is a meniscus lens having a positive refractive power with the convex surface facing the object side.

The third group G ₃ includes, in order from the object side, a lens L ₃₁ that is a biconvex lens, a lens L ₃₂ that is a meniscus lens having a positive refractive power with a concave surface facing the object side in order from the object side, and a concave surface on the object side. is composed of a cemented lens consisting of a lens L ₃₃ Metropolitan is a meniscus lens having negative refractive power with a.

The fourth group G ₄ includes, in order from the object side, a lens L ₄₁ that is a meniscus lens having a negative refractive power with a convex surface facing the object side, a lens L ₄₂ that is a biconcave lens, and a biconvex lens in order from the object side. It is composed of a cemented lens consisting of a lens L ₄₃ Prefecture.

Further, when focusing from infinity focus to a close object in-focus condition to be photographed magnification magnification, the first group G ₁ is not moved along the optical axis Lc. The second group G ₂ moves to the image side on the optical axis Lc while widening the interval with the first group G ₁ . The third group G ₃ moves toward the object side on the optical axis Lc while narrowing the interval with the second group G ₂ . The fourth group G ₄ does not move on the optical axis Lc. The aperture stop S, because it is configured third group G ₃ integrally with and moves together with the third group G _3.

  Next, numerical data relating to the lens constituting the macro lens of the present embodiment will be shown.

Numerical data 4
Unit mm
Surface data Surface number Curvature radius Surface spacing Refractive index Abbe number s r d nd νd
1 109.594 6.00 1.48749 70.23
2 -346.817 0.20
3 121.436 1.00 1.91082 35.25
4 46.340 10.70 1.49700 81.54
5 -144.246 0.15
6 41.119 5.13 1.49700 81.54
7 64.909 D7
8 -913.075 2.00 1.69680 55.53
9 40.569 1.50
10 30.348 8.40 1.59270 35.31
11 534.392 1.50
12 -1032.291 2.00 1.69680 55.53
13 29.802 2.00
14 38.682 4.00 1.78472 25.68
15 54.797 D15
16 (Aperture) ∞ 0.20
17 87.987 5.79 1.88300 40.76
18 -78.985 0.20
19 -150.771 3.25 1.59282 68.63
20 -37.764 1.00 1.84666 23.78
21 -155.317 D21
22 58.672 1.40 1.48749 70.23
23 27.002 8.23
24 -56.257 1.40 1.62588 35.70
25 63.710 3.69 1.85026 32.27
26 -96.400 D26
27 ∞ 4.2 1.51633 64.14
28 ∞ D28
29 (Image plane) ∞

Various data
Magnification at infinity -0.5 -1
Focal length 149.90 106.32 77.58
F number 2.83 1.63 1.01
Angle of view (2ω) 8.40 4.73 3.33
Image height 11.15 11.15 11.15
Total length 196.63 196.63 196.63
Back focus (in air) 43.07 43.07 43.07

Plane interval Shooting magnification Infinite -0.5 -1
D7 9.74 16.79 27.36
D15 64.10 31.71 4.51
D21 10.00 35.34 51.97
D26 39.00 39.00 39.00
D28 1.30 1.30 1.30

Lens group data Group Start surface Focal length
1 1 80.63
2 8 -58.32
3 17 63.04
4 22 -128.85

Data related to the above conditional expression (1): 0.08 <ΣD _G1L /L<0.181 : 0.15094
Formula (2): 0.27 <( _{DG2 -G3i-DG2-G3s} ) / L <0.6: 0.388
Formula (3): 0.4 <Ls _G2n <2 : 0.914
Formula (4): −33 <Ls _G2p <−1 : -1.120
Formula (5): 0.05 <D _G2F / D _G3F <0.710 : 0.419
Formula (6): 0.2 <| f _G3 / f _G2 | <2.0 : 1.08
Formula (7): 0.1 <(D _G4Amax + bf) / f _i <0.7 : 0.342
Formula (8): 0.08 <D _G4Amax /f<0.3 : −
Formula (9): 0.5 <D _G4Amax /BF<1.8 : −
Formula (10): −0.33 <Ls _G1p2 −Ls _G1p3 <10 : 4.37
Formula (11): 0.34 <f _G1 /f<0.57 : 0.5375
Formula (12): 70 <νd _G1pa <95 : 77.77
Formula (13): 1.8 <n _G1na <2.1 : 1.91082

  The macro lens according to Example 5 will be described in detail below with reference to FIGS.

  FIG. 13 is a cross-sectional view along the optical axis showing the configuration of the macro lens according to the present embodiment, where (a) is an infinite object focusing state, and (b) is an intermediate state (shooting magnification 0.5 times). ) And (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. An arrow between (a) and (b) represents the moving direction of each lens group when the observation state is changed from the infinite object focusing state to the intermediate state (shooting magnification 0.5 times). The arrows between (b) and (c) indicate the movement of each lens group when changing the observation state from an intermediate state (shooting magnification of 0.5 times) to a short-distance object in-focus state where the shooting magnification is the same magnification. It represents the direction. 14A and 14B are diagrams showing coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 13 is d, where FIG. 14A is an infinite object focusing state, and FIG. 14B is an intermediate state ( (Capturing magnification 0.5 times) and (c) respectively show a short-distance object focusing state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm). 15A and 15B are diagrams showing coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 13 is d, where FIG. 15A is an infinite object focusing state, and FIG. 15B is an intermediate state ( (Capturing magnification 0.5 times) and (c) respectively show a short-distance object focusing state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm).

The macro lens of the present embodiment is arranged in order from the object side on the optical axis Lc, a positive first group G ₁ , a negative second group G ₂ , a positive third group G ₃ , and a negative fourth group G _4. Is arranged. Note that an aperture stop S configured integrally with the third group G ₃ is disposed between the third group G ₃ and the fourth group G ₄ . Further, on the image side of the fourth group G ₄ is composed of, in order from the object side, CCD cover glass CG, and a CCD having an imaging surface IM are arranged.

The first group G ₁ includes a lens L ₁₁ that is a biconvex lens in order from the object side, a lens L ₁₂ that is a meniscus lens having a negative refractive power with a convex surface facing the object side in order from the object side, and a biconvex lens. The lens L ₁₃ is a cemented lens, and the lens L ₁₄ is a meniscus lens having a positive refractive power with a convex surface facing the object side.

The second group G ₂ includes, in order from the object side, a lens L ₂₁ that is a meniscus lens having a negative refractive power with a convex surface facing the object side, and a meniscus lens having a positive refractive power with a convex surface facing the object side. A lens L ₂₂ , a lens L ₂₃ having a negative refractive power with a convex surface facing the object side, and a lens L ₂₄ having a positive refractive power with a convex surface facing the object side. It is composed of a cemented lens.

The third group G ₃ is a lens L ₃₁ that is a biconvex lens in order from the object side, a lens L ₃₂ that is a biconvex lens in order from the object side, and a meniscus lens having negative refractive power with a concave surface facing the object side. It is composed of a cemented lens consisting of a lens L ₃₃ Prefecture.

The fourth group G ₄ includes, in order from the object side, a lens L ₄₁ that is a meniscus lens having a negative refractive power with a convex surface facing the object side, a lens L ₄₂ that is a biconcave lens, and a biconvex lens in order from the object side. It is composed of a cemented lens consisting of a lens L ₄₃ Prefecture.

Further, when focusing from infinity focus to a close object in-focus condition to be photographed magnification magnification, the first group G ₁ is not moved along the optical axis Lc. The second group G ₂ moves to the image side on the optical axis Lc while widening the interval with the first group G ₁ . The third group G ₃ moves toward the object side on the optical axis Lc while narrowing the interval with the second group G ₂ . The fourth group G ₄ does not move on the optical axis Lc. The aperture stop S, because it is configured third group G ₃ integrally with and moves together with the third group G _3.

  Next, numerical data relating to the lens constituting the macro lens of the present embodiment will be shown.

Numerical data 5
Unit mm
Surface data Surface number Curvature radius Surface spacing Refractive index Abbe number s r d nd νd
1 171.507 5.00 1.48749 70.23
2 -266.287 0.20
3 95.478 1.49 1.80610 40.92
4 43.781 8.44 1.49700 81.54
5 -12876.783 0.15
6 49.788 4.85 1.49700 81.54
7 159.479 D7
8 324.026 3.00 1.69680 55.53
9 47.320 1.20
10 34.785 4.00 1.61800 63.33
11 36.941 3.00
12 61.960 2.00 1.69680 55.53
13 29.869 3.00 1.78472 25.68
14 45.962 D14
15 (Aperture) ∞ 1.00
16 88.131 3.81 1.49700 81.54
17 -96.136 0.20
18 82.890 3.73 1.59282 68.63
19 -83.913 1.77 1.80518 25.42
20 -59593.690 D20
21 145.653 1.40 1.48749 70.23
22 19.073 19.14
23 -85.593 1.40 1.62588 35.70
25 22.083 5.96 1.85026 32.27
25 -96.400 D25
26 ∞ 4.2 1.51633 64.14
27 ∞ D27
28 (Image plane) ∞

Various data
Magnification at infinity -0.5 -1
Focal length 149.94 117.90 92.43
F number 2.83 1.96 1.43
Angle of view (2ω) 8.39 5.17 3.96
Image height 11.15 11.15 11.15
Total length 174.63 174.63 174.63
Back focus (in air) 14.07 14.07 14.07

Plane interval Shooting magnification Infinite -0.5 -1
D7 7.59 15.26 25.70
D14 60.22 30.79 4.79
D20 18.01 39.77 55.32
D25 10.00 10.00 10.00
D27 1.30 1.30 1.30

Lens group data Group Start surface Focal length
1 1 78.30
2 8 -70.84
3 16 64.94
4 21 -221.24

Data related to the above conditional expression (1): 0.08 <ΣD _G1L /L<0.181 : 0.12539
Formula (2): 0.27 <( _{DG2 -G3i-DG2-G3s} ) / L <0.6: 0.345
Formula (3): 0.4 <Ls _G2n <2 : 1.342
Formula (4): −33 <Ls _G2p <−1 : -33.27
Formula (5): 0.05 <D _G2F / D _G3F <0.710 : 0.485
Formula (6): 0.2 <| f _G3 / f _G2 | <2.0 : 0.91
Formula (7): 0.1 <(D _G4Amax + bf) / f _i <0.7 : 0.221
Formula (8): 0.08 <D _G4Amax /f<0.3 : 0.127
Formula (9): 0.5 <D _G4Amax /BF<1.8 : 1.36
Formula (10): −0.33 <Ls _G1p2 −Ls _G1p3 <10 : 0.907
Formula (11): 0.34 <f _G1 /f<0.57 : 0.522
Formula (12): 70 <νd _G1pa <95 : 77.77
Formula (13): 1.8 <n _G1na <2.1 : 1.8061

  The macro lens according to Example 6 will be described below in detail with reference to FIGS.

  FIGS. 16A and 16B are cross-sectional views along the optical axis showing the configuration of the macro lens according to the present embodiment. FIG. 16A is an infinite object focusing state, and FIG. 16B is an intermediate state (shooting magnification of 0.5 times). ) And (c) respectively show a short-distance object in-focus state where the photographing magnification is equal. An arrow between (a) and (b) represents the moving direction of each lens group when the observation state is changed from the infinite object focusing state to the intermediate state (shooting magnification 0.5 times). The arrows between (b) and (c) indicate the movement of each lens group when changing the observation state from an intermediate state (shooting magnification of 0.5 times) to a short-distance object in-focus state where the shooting magnification is the same magnification. It represents the direction. 17A and 17B are diagrams showing coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 16 is d, where FIG. 17A is an infinite object focusing state, and FIG. 17B is an intermediate state ( (Capturing magnification 0.5 times) and (c) respectively show a short-distance object focusing state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm). 18A and 18B are diagrams showing coma aberration of 0.35d when the real image height of the macro lens shown in FIG. 16 is d, where FIG. 18A is an infinite object focusing state, and FIG. 18B is an intermediate state ( (Capturing magnification 0.5 times) and (c) respectively show a short-distance object focusing state where the photographing magnification is equal. The horizontal axis represents the aperture ratio (−1 to 1), and the vertical axis represents the aberration amount (mm).

The macro lens of the present embodiment is arranged in order from the object side on the optical axis Lc, a positive first group G ₁ , a negative second group G ₂ , a positive third group G ₃ , and a negative fourth group G _4. Is arranged. Note that an aperture stop S configured integrally with the third group G ₃ is disposed between the third group G ₃ and the fourth group G ₄ . Further, on the image side of the fourth group G ₄ is composed of, in order from the object side, CCD cover glass CG, and a CCD having an imaging surface IM are arranged.

The first lens group G ₁ includes, in order from the object side, a cemented lens including a lens L ₁₁ that is a meniscus lens having a negative refractive power with a convex surface facing the object side in order from the object side, and a lens L ₁₂ that is a biconvex lens. The lens L ₁₃ is a biconvex lens and the lens L ₁₄ is a meniscus lens having a positive refractive power with a convex surface facing the object side.

The second group G ₂ has, in order from the object side, a lens L ₂₁ that is a biconcave lens, a lens L ₂₂ that is a meniscus lens having a positive refractive power with the convex surface facing the object side, and a convex surface facing the object side. The lens L ₂₃ is a meniscus lens having negative refractive power, and the lens L ₂₄ is a meniscus lens having positive refractive power with a convex surface facing the object side.

The third group G ₃ includes, in order from the object side, a lens L _{31 that} is a biconvex lens, a lens L ₃₂ that is a biconvex lens, and a lens L ₃₃ that is a meniscus lens having a negative refractive power with a concave surface facing the object side. It is comprised by the cemented lens which consists of.

The fourth group G ₄ includes, in order from the object side, a lens L ₄₁ that is a meniscus lens having a negative refractive power with a convex surface facing the object side, a lens L ₄₂ that is a biconcave lens, and a biconvex lens in order from the object side. They are composed of a cemented lens consisting of a lens L ₄₃ Prefecture.

Further, when focusing from infinity focus to a close object in-focus condition to be photographed magnification magnification, the first group G ₁ is not moved along the optical axis Lc. The second group G ₂ moves to the image side on the optical axis Lc while widening the interval with the first group G ₁ . The third group G ₃ moves toward the object side on the optical axis Lc while narrowing the interval with the second group G ₂ . The fourth group G ₄ does not move on the optical axis Lc. The aperture stop S, because it is configured third group G ₃ integrally with and moves together with the third group G _3.

  Next, numerical data relating to the lens constituting the macro lens of the present embodiment will be shown.

Numerical data 6
Unit mm
Surface data Surface number Curvature radius Surface spacing Refractive index Abbe number s r d nd νd
1 186.560 3.00 1.80518 25.42
2 80.048 10.00 1.48749 70.23
3 -142.320 0.20
4 133.231 6.00 1.49700 81.54
5 -536.108 0.15
6 80.904 11.47 1.43875 94.93
7 331.591 D7
8 -183.988 3.00 1.69680 55.53
9 62.191 1.20
10 29.971 5.00 1.59270 35.31
11 84.184 2.80
12 93.733 3.00 1.69680 55.53
13 26.107 2.00
14 33.758 3.00 1.78472 25.68
15 44.155 D15
16 (Aperture) ∞ 0.20
17 86.927 2.65 1.49700 81.54
18 -69.425 0.20
19 43.677 3.65 1.59282 68.63
20 -57.372 1.00 1.80518 25.42
21 -571.097 D21
22 170.208 1.40 1.48749 70.23
23 20.261 6.85
24 -40.958 1.40 1.62588 35.70
25 28.856 4.00 1.85026 32.27
26 -96.400 D26
27 ∞ 4.2 1.51633 64.14
28 ∞ D28
29 (Image plane) ∞

Various data
Magnification at infinity -0.5 -1
Focal length 152.96 103.21 67.97
F number 2.86 0.81 0.16
Angle of View (2ω) 8.24 2.75 0.67
Image height 11.15 11.15 11.15
Total length 183.63 183.63 183.63
Back focus (in air) 42.63 42.63 42.63

Plane interval Shooting magnification Infinite -0.5 -1
D7 7.68 24.36 46.38
D15 58.59 33.48 4.99
D21 2.57 11.01 17.47
D26 38.55 38.55 38.55
D28 1.30 1.30 1.30

Lens group data Group Start surface Focal length
1 1 80.51
2 8 -65.21
3 17 41.56
4 22 -54.01

Data related to the above conditional expression (1): 0.08 <ΣD _G1L /L<0.181 : 0.1659
Formula (2): 0.27 <( _{DG2 -G3i-DG2-G3s} ) / L <0.6: 0.2918
Formula (3): 0.4 <Ls _G2n <2 : 0.49477
Formula (4): −33 <Ls _G2p <−1 : -2.10568
Formula (5): 0.05 <D _G2F / D _G3F <0.710 :-
Formula (6): 0.2 <| f _G3 / f _G2 | <2.0 : 0.6373
Formula (7): 0.1 <(D _G4Amax + bf) / f _i <0.7 : 0.3234
Formula (8): 0.08 <D _G4Amax /f<0.3 : 0.16068
Formula (9): 0.5 <D _G4Amax /BF<1.8 : −
Formula (10): −0.33 <Ls _G1p2 −Ls _G1p3 <10 : −
Formula (11): 0.34 <f _G1 /f<0.57 : 0.5263
Formula (12): 70 <νd _G1pa <95 : 82.23
Formula (13): 1.8 <n _G1na <2.1 : 1.805518

  Further, the lenses constituting the lens group of the macro lens of the present invention are not limited to the shapes and the number of sheets shown in the above embodiments.

  Although not arranged in each of the above embodiments, a low-pass filter or the like having an IR cut coat may be arranged between the macro lens and the image sensor.

CG cover glass G ₁ first group G ₂ second group G ₃ third group G ₄ Group 4 LC optical axis _{L 11, L 12, L 13} , L 14, L 21, L 22, L 23, L 24, L ₃₁ , L ₃₂ , L ₃₃ , L ₄₁ , L ₄₂ , L ₄₃ Lens S Aperture stop

Claims (14)

In order from the object side, the first group that is positive, the second group that is negative, the third group that is positive, and the fourth group that is negative. In a macro lens in which the first group and the fourth group do not move, the second group moves to the image side, and the third group moves to the object side during focusing to the object in-focus state,
The second group includes a negative lens that is disposed closest to the object side and has a concave surface facing the image side, and a positive lens that is disposed closer to the image side than the negative lens and has a convex surface facing the object side. Consisting of two or more lenses,
A macro lens satisfying the following conditional expression (1):
0.08 <ΣD _{G1L /L<0.181} (1)
Where ΣD _G1L is the total thickness of the lenses constituting the first group on the optical axis, and L is the image side surface of the most image side lens from the object side surface of the most object side lens on the optical axis. Is the length. In order from the object side, the first group that is positive, the second group that is negative, the third group that is positive, and the fourth group that is negative. In a macro lens in which the first group and the fourth group do not move, the second group moves to the image side, and the third group moves to the object side during focusing to the object in-focus state,
The first group is composed of four lenses,
All the lenses constituting the first group have their convex surfaces facing the object side,
The most object side lens among the lenses constituting the first group is a positive lens component,
The positive lens component is a positive lens alone or a cemented lens having positive power as a whole,
A macro lens satisfying the following conditional expression (2):
0.27 <( _{DG2-G3i-DG2 -G3s} ) / L <0.6 (2)
Where D _G2-G3i is the distance between the second group and the third group in the infinite object focusing state, and D _G2-G3s is the second group in the short-distance object focusing state at the same magnification as the shooting magnification. The distance from the third lens unit, L, is the length from the object-side surface of the most object-side lens on the optical axis to the image-side surface of the most image-side lens. In order from the object side, the first group that is positive, the second group that is negative, the third group that is positive, and the fourth group that is negative. In a macro lens in which the first group and the fourth group do not move, the second group moves to the image side, and the third group moves to the object side during focusing to the object in-focus state,
The first group is composed of four lenses,
All the lenses constituting the first group have their convex surfaces facing the object side,
The most object side lens among the lenses constituting the first group is a positive lens component,
The positive lens component is a positive lens alone or a cemented lens having positive power as a whole,
A macro lens characterized by satisfying the following conditional expressions (1) and (2):
0.08 <ΣD _{G1L /L<0.181} (1)
0.27 <( _{DG2-G3i-DG2 -G3s} ) / L <0.6 (2)
Where ΣD _G1L is the total thickness of the lenses constituting the first group on the optical axis, and L is the image side surface of the most image side lens from the object side surface of the most object side lens on the optical axis. D _G2-G3i is the distance between the second group and the third group in the infinite object focusing state, and D _G2-G3s is the second group and the third in the infinite object focusing state. The distance from the group. The second group includes a negative lens that is disposed closest to the object side and has a concave surface facing the image side, and a positive lens that is disposed closer to the image side than the negative lens and has a convex surface facing the object side. The macro lens according to claim 2, comprising at least two lenses. Macro lens according to claim 1 or 4, characterized by satisfying the following condition (3).
0.4 <Ls _G2n <2 (3)
Where Ls _G2n = (r _G2nf + r _G2nb ) / (r _G2nf −r _G2nb ), r _G2nf is the radius of curvature of the object side surface of the negative lens included in the second group, and r _G2nb is the second radius This is the radius of curvature of the image side surface of the negative lens included in the group. The macro lens according to claim 1 , wherein the following conditional expression (4) is satisfied.
−33 <Ls _G2p <−1 (4)
Where Ls _G2p = (r _G2pf + r _G2pb ) / (r _G2pf −r _G2pb ), r _G2pf is the radius of curvature of the object side surface of the positive lens included in the second group, and r _G2nb is the second radius This is the radius of curvature of the image-side surface of the positive lens included in the group. The lens arranged closest to the object side in the first group is a positive lens,
Macro lens according to any one of claims 1 to 6, characterized by satisfying the following condition (5).
0.05 < _DG2F / _DG3F <0.710 (5)
However, D _G2F is the movement amount during focusing of the second group, and D _G3F is the movement amount during focusing of the third group. Macro lens according to any one of claims 1 to 7, characterized by satisfying the following condition (6).
0.2 <| _fG3 / _fG2 | <2.0 (6)
Here, f _G3 is the focal length of the third group, and f _G2 is the focal length of the second group. The fourth group comprises at least two lenses;
Macro lens according to any one of claims 1 to 8, characterized by satisfying the following condition (7).
0.1 <(D _G4Amax + bf) / f _i <0.7 (7)
However, _DG4Amax is the longest length of the air space between the lenses constituting the fourth group on the optical axis, bf is the back focus, and f _i is the focal length in the infinite object focusing state. The fourth group comprises at least two lenses ;
The macro lens according to any one of claims 1 to 9 , wherein the following conditional expression (8) is satisfied.
0.08 < _DG4Amax / f <0.3 (8)
However, _DG4Amax is the longest length of the air gap between the lenses constituting the fourth group on the optical axis, and f is the focal length of the entire system in the infinite object focused state. The macro lens according to claim 10 , wherein the following conditional expression (9) is satisfied.
0.5 <D _G4Amax / BF <1.8 (9)
However, _DG4Amax is the longest length of the air space between the lenses constituting the fourth group on the optical axis, and BF is the back focus. The first group includes, in order from the object side, a positive lens, a cemented lens including a negative lens and a positive lens in order from the object side, and a positive lens.
Macro lens according to any one of claims 1 to 11, characterized by satisfying the following condition (10).
−0.33 <Ls _G1p2 −Ls _G1p3 <10 (10)
However, _LsG1p2 = ( _rG1p2f + _rG1p2b ) / ( _{rG1p2f− rG1p2b} ), _LsG1p3 = ( _rG1p3f + _rG1p3b ) / ( _{rG1p3f− rG1p3b} ), and the _rG1p2f is included in the _rG1p2f The radius of curvature of the object side surface of the second positive lens from the object side, r _G1p2b is the radius of curvature of the image side surface of the second positive lens included in the first group, and r _G1p3f is the first radius of curvature. The radius of curvature of the object side surface of the third positive lens included in the group, r _G1p3b is the radius of curvature of the image side surface of the third positive lens included in the first group. Macro lens according to any one of claims 1 to 12, characterized by satisfying the following condition (11).
0.34 < _fG1 / f <0.57 (11)
Here, f _G1 is the focal length of the first group, and f is the focal length of the entire system in the state of focusing on an object at infinity. Following condition (12) and a macro lens according to any one of claims 1 to 13, characterized by satisfying the (13).
70 <νd _G1pa <95 (12)
1.8 <n _G1na <2.1 (13)
Where νd _G1pa is the average Abbe number for the d-line of lenses having a positive refractive power among the lenses constituting the first group, and n _G1na is the negative refractive power of the lenses constituting the first group. This is the average value of the refractive index of the lens.

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