JP6406660B2 - Zoom lens and imaging apparatus having the same - Google Patents

Description

  The present invention relates to a zoom lens and an imaging apparatus having the same.

  A wide-angle lens is known as a lens capable of photographing a wide range. Conventional wide-angle lenses include the wide-angle lenses disclosed in Patent Documents 1, 2, and 3.

JP 2010-060612 A JP 2010-176098 A JP 2010-249959 A

  The wide-angle lens of Patent Document 1 has a long back focus with respect to the entire length of the optical system, or a focal length at the wide-angle end with respect to the focal length of the first lens group. Therefore, in the wide-angle lens of Patent Document 1, it is difficult to sufficiently reduce the size of the optical system.

  Further, in the wide-angle lens of Patent Document 2, the F number is not sufficiently small, or the angle of view cannot be sufficiently widened compared to the F number. Further, the focal length at the wide angle end is longer than the focal length of the first lens group. Therefore, in the wide-angle lens of Patent Document 1, it is difficult to sufficiently reduce the size of the optical system.

  In the wide-angle lens disclosed in Patent Document 3, the lens group closest to the object includes a focus lens group. With such a configuration, it is difficult to reduce the size and weight of the focus lens group. In addition, for this reason, it is difficult to reduce the size and weight of the drive mechanism of the focus lens group. As a result, with the wide-angle lens of Patent Document 3, it is difficult to increase the focus speed.

  The present invention has been made in view of such problems, and the optical system is sufficiently reduced in size and weight, and various aberrations are achieved while having a sufficiently wide angle of view as compared with the F-number. It is an object to provide a sufficiently reduced zoom lens and an image pickup apparatus having the zoom lens.

In order to solve the above-described problems and achieve the object, the zoom lens according to the first aspect of the invention includes:
From the object side to the image side,
A front group having negative refractive power;
A rear group including an aperture stop and having a positive refractive power,
The front group includes a first lens having a negative refractive power and a third lens having a positive refractive power;
The first lens is disposed closest to the object side, and the shape thereof is a meniscus shape having a convex surface facing the object side,
The front group consists of the first lens group,
When zooming from the wide-angle end to the telephoto end, the first lens unit moves as a unit,
The rear group is in order from the object side to the image side,
A second lens group having a positive refractive power and positioned closer to the object side than the aperture stop;
A third lens group;
A fourth lens group having negative refractive power;
A fifth lens group having a positive refractive power,
The second lens group or the third lens group has a focus lens group,
When zooming from the wide-angle end to the telephoto end,
The interval between each lens group changes, and
The distance between the front group and the rear group is narrow,
The following conditional expression is satisfied.
1.65 <SP _F1 <9.0
here,
SP _F1 = (r _F1o + r _F1i ) / (r _F1o -r _F1i )
r _F1o is the paraxial radius of curvature of the object side of the first lens,
r _F1i is the paraxial radius of curvature of the image side of the first lens,
It is.

The zoom lens of the invention of the second aspect is
From the object side to the image side,
A front group having negative refractive power;
A rear group including an aperture stop and having a positive refractive power,
The front group includes a first lens having a negative refractive power and a third lens having a positive refractive power;
The first lens is disposed closest to the object side, and the shape thereof is a meniscus shape having a convex surface facing the object side,
The front group consists of the first lens group,
When zooming from the wide-angle end to the telephoto end, the first lens unit moves as a unit,
The rear group is in order from the object side to the image side,
A second lens group having a positive refractive power and positioned closer to the object side than the aperture stop;
A third lens group;
A fourth lens group having negative refractive power;
A fifth lens group having a positive refractive power,
The rear group includes a second lens group, a third lens group, a fourth lens group, and a fifth lens group, or
The rear group includes a second lens group, a third lens group, a fourth lens group, a fifth lens group, and a sixth lens group.
The second lens group or the third lens group has a focus lens group,
When zooming from the wide-angle end to the telephoto end,
The interval between each lens group changes, and
The distance between the front group and the rear group is narrow,
The following conditional expression is satisfied.
−1.45 <FB _w / f _F <−0.3
here,
FB _w is the back focus at the wide-angle end,
f _F is the focal length of the front group,
It is.

The zoom lens according to the invention of the third aspect is
From the object side to the image side,
A front group having negative refractive power;
A rear group including an aperture stop and having a positive refractive power,
The front group includes a first lens having a negative refractive power and a third lens having a positive refractive power;
The first lens is disposed closest to the object side, and the shape thereof is a meniscus shape having a convex surface facing the object side,
The front group consists of the first lens group,
When zooming from the wide-angle end to the telephoto end, the first lens unit moves as a unit,
The rear group is in order from the object side to the image side,
A second lens group having a positive refractive power and positioned closer to the object side than the aperture stop;
A third lens group;
A fourth lens group having negative refractive power;
A fifth lens group having a positive refractive power,
The second lens group or the third lens group has a focus lens group,
When zooming from the wide-angle end to the telephoto end,
The interval between each lens group changes, and
The distance between the front group and the rear group is narrow,
The following conditional expression is satisfied.
74 <νd _Fnmax <110
here,
νd _Fnmax is the maximum Abbe number among the Abbe numbers of lenses having negative refractive power included in the front group,
It is.

Moreover, the zoom lens of the invention of the fourth aspect is
From the object side to the image side,
A front group having negative refractive power;
A rear group including an aperture stop and having a positive refractive power,
The front group includes a first lens having a negative refractive power and a third lens having a positive refractive power;
The first lens is disposed closest to the object side, and the shape thereof is a meniscus shape having a convex surface facing the object side,
The front group consists of the first lens group,
When zooming from the wide-angle end to the telephoto end, the first lens unit moves as a unit,
The rear group is in order from the object side to the image side,
A second lens group having a positive refractive power and positioned closer to the object side than the aperture stop;
A third lens group;
A fourth lens group having negative refractive power;
A fifth lens group having a positive refractive power,
The second lens group has a focus lens group,
When zooming from the wide-angle end to the telephoto end,
The interval between each lens group changes, and
The distance between the front group and the rear group is narrow,
The following conditional expression is satisfied.
1.2 <f _Rw / FB _w <5
here,
f _Rw is the focal length of the rear group at the wide angle end,
FB _w is the back focus at the wide-angle end,
It is.

The imaging device of the present invention is
Any one of the above zoom lenses;
And an imaging device that has an imaging surface and converts an image formed on the imaging surface by a zoom lens into an electrical signal.

  According to the present invention, a zoom lens in which the optical system is sufficiently reduced in size and weight and has a sufficiently wide angle of view compared to the F-number, and various aberrations are sufficiently reduced, and an image pickup having the same Equipment can be provided.

FIG. 4 is a lens cross-sectional view of the zoom lens according to Example 1 when focusing on an object at infinity, where (a) is a lens cross-sectional view at a wide angle end, (b) is an intermediate end, and (c) is a lens cross-sectional view at a telephoto end. FIG. 4 is a lens cross-sectional view of a zoom lens according to Example 2 when an object at infinity is focused, where (a) is a lens cross-sectional view at a wide-angle end, (b) is an intermediate end, and (c) is a lens cross-sectional view at a telephoto end. FIG. 6 is a lens cross-sectional view of a zoom lens according to Example 3 when an object at infinity is focused, where (a) is a lens cross-sectional view at the wide-angle end, (b) is an intermediate end, and (c) is a lens cross-sectional view at a telephoto end. FIG. 6 is a lens cross-sectional view of a zoom lens according to Example 4 when an object at infinity is focused, where (a) is a lens cross-sectional view at a wide-angle end, (b) is an intermediate end, and (c) is a lens cross-sectional view at a telephoto end. FIG. 7A is a lens cross-sectional view of a zoom lens according to Example 5 when an object at infinity is in focus, where FIG. 5A is a lens cross-sectional view at a wide-angle end, FIG. FIG. 10 is a lens cross-sectional view of a zoom lens according to Example 6 when an object at infinity is focused, where (a) is a wide-angle end, (b) is an intermediate end, and (c) is a lens cross-sectional view at a telephoto end. FIG. 6 is a diagram illustrating spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (CC) when an object at infinity is in focus in the zoom lens according to the first embodiment; d) shows the state at the wide angle end, (e) to (h) show the state at the middle, and (i) through (l) show the state at the telephoto end. FIG. 6 is a diagram illustrating spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (CC) when focusing on a short-distance object in the zoom lens according to Example 1; d) shows the state at the wide angle end, (e) to (h) show the state at the middle, and (i) through (l) show the state at the telephoto end. FIG. 7 is a diagram illustrating spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (CC) when the zoom lens according to Example 2 is focused on an object at infinity. d) shows the state at the wide angle end, (e) to (h) show the state at the middle, and (i) through (l) show the state at the telephoto end. FIG. 6 is a diagram illustrating spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (CC) when focusing on a short distance object of a zoom lens according to Example 2; d) shows the state at the wide angle end, (e) to (h) show the state at the middle, and (i) through (l) show the state at the telephoto end. FIG. 10 is a diagram illustrating spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (CC) when the zoom lens according to Example 3 is focused on an object at infinity. d) shows the state at the wide angle end, (e) to (h) show the state at the middle, and (i) through (l) show the state at the telephoto end. FIG. 10 is a diagram illustrating spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (CC) when focusing on a short-distance object in the zoom lens according to Example 3; d) shows the state at the wide angle end, (e) to (h) show the state at the middle, and (i) through (l) show the state at the telephoto end. FIG. 10 is a diagram illustrating spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (CC) when the zoom lens according to Example 4 is focused on an object at infinity. d) shows the state at the wide angle end, (e) to (h) show the state at the middle, and (i) through (l) show the state at the telephoto end. FIG. 10 is a diagram illustrating spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (CC) when focusing on a short distance object of a zoom lens according to Example 4; d) shows the state at the wide angle end, (e) to (h) show the state at the middle, and (i) through (l) show the state at the telephoto end. FIG. 7A is a diagram illustrating spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (CC) when an object at infinity is in focus in a zoom lens according to Example 5; d) shows the state at the wide angle end, (e) to (h) show the state at the middle, and (i) through (l) show the state at the telephoto end. FIG. 10 is a diagram illustrating spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (CC) when focusing on a short-distance object in the zoom lens according to Example 5; d) shows the state at the wide angle end, (e) to (h) show the state at the middle, and (i) through (l) show the state at the telephoto end. FIG. 10 is a diagram illustrating spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (CC) when the zoom lens according to Example 6 is focused on an object at infinity. d) shows the state at the wide angle end, (e) to (h) show the state at the middle, and (i) through (l) show the state at the telephoto end. FIG. 10 is a diagram illustrating spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (CC) when a short-distance object is focused by a zoom lens according to Example 6; d) shows the state at the wide angle end, (e) to (h) show the state at the middle, and (i) through (l) show the state at the telephoto end. It is sectional drawing of an imaging device. It is a front perspective view showing an outline of an imaging device. It is a back perspective view of an imaging device. It is a block diagram of the internal circuit of the main part of the imaging apparatus.

  Prior to the description of the examples, effects of the embodiment according to an aspect of the present invention will be described. It should be noted that, when the operational effects of the present embodiment are specifically described, a specific example will be shown and described. However, as in the case of the embodiments to be described later, those exemplified aspects are only a part of the aspects included in the present invention, and there are many variations in the aspects. Therefore, the present invention is not limited to the illustrated embodiment.

  The zoom lens according to this embodiment will be described. First, the basic configuration will be described.

  In the basic configuration of the zoom lens of the present embodiment, the zoom lens includes, in order from the object side to the image side, a front group having a negative refractive power, and a rear group including an aperture stop and having a positive refractive power, The front group includes a first lens having a negative refractive power and a third lens having a positive refractive power. The first lens is disposed closest to the object side, and the shape thereof is the object side. A rear lens group having a positive refractive power in order from the object side to the image side, and a second lens group positioned closer to the object side than the aperture stop, a third lens group, A fourth lens group having a negative refractive power and a fifth lens group having a positive refractive power, and the second lens group or the third lens group has a focus lens group and is telephoto from the wide-angle end. When zooming to the end, the distance between the lens groups changes, and the distance between the front group and the rear group is narrow. .

  In the basic configuration, the zoom lens includes, in order from the object side to the image side, a front group that has a negative refractive power and a rear group that includes an aperture stop and has a positive refractive power. Thereby, the configuration of the optical system can be a retrofocus type configuration. As a result, it is easy to ensure a back focus with an appropriate length while having an ultra-wide angle of view. Here, the ultra-wide field angle is, for example, a field angle of 105 ° or more, and more preferably a field angle of 110 ° or more.

  In the basic configuration, the front group includes a first lens having a negative refractive power and a third lens having a positive refractive power, and the first lens is disposed closest to the object side, and The shape is a meniscus shape having a convex surface facing the object side.

  As described above, the front group has a negative refractive power. Therefore, when the negative refractive power of the front group is increased, the diameter of the optical system can be reduced. However, the amount of curvature of field and astigmatism tends to increase as the height of the off-axis principal ray increases. Here, in the ultra-wide field angle optical system, the height of the off-axis principal ray is highest when passing through the front group. Therefore, if the negative refractive power of the front group is increased, the amount of field curvature and astigmatism is likely to increase when the field angle is set to an ultra-wide field angle.

  Therefore, a first lens having negative refractive power is disposed in the front group. The first lens is arranged on the most object side of the front group, and the shape of the first lens is a meniscus shape having a convex surface facing the object side.

  As a result, at least one meniscus lens having a concave surface facing the aperture stop is disposed in the front group where the height of the off-axis principal ray is the highest. By doing so, off-axis rays can be gradually refracted while increasing the negative refractive power in the front group. That is, rapid refraction of light rays can be suppressed. As a result, it is possible to make the angle of view an ultra-wide angle of view while reducing the amount of curvature of field and astigmatism.

  Furthermore, a third lens having a positive refractive power is arranged in the front group. By doing in this way, generation | occurrence | production of an axial chromatic aberration and a magnification chromatic aberration can be suppressed. In addition, the amount of spherical aberration generated near the telephoto end can be reduced.

  Further, when zooming from the wide-angle end to the telephoto end, the distance between the front group and the rear group becomes narrow. By doing so, a large zooming effect can be obtained. The interval between the front group and the rear group is a paraxial interval.

  The rear group has a positive refractive power in order from the object side to the image side, a second lens group located on the object side from the aperture stop, a third lens group, and a fourth lens having a negative refractive power. A lens group and a fifth lens group having a positive refractive power. The distance between the lens groups changes during zooming from the wide-angle end to the telephoto end. The interval between the lens groups is a paraxial interval.

  As described above, in the basic configuration, the configuration of the optical system is a retrofocus type configuration. In the retrofocus type configuration, in order to further reduce the diameter of the optical system, it is necessary to increase the negative refractive power of the front group. In particular, in an ultra-wide angle zoom lens, for example, in order to shorten the overall length of the optical system while ensuring a zoom ratio of 1.9 times or more, not only the front group but also the rear group has a large refractive power. There is a need to.

  Here, if the negative refractive power of the front group is increased too much, a large positive field curvature occurs in the front group, and off-axis aberrations, particularly astigmatism, tend to fluctuate during zooming. Therefore, it is necessary to correct aberrations well in the rear group in order to reduce the generation amount of aberrations and suppress fluctuations in aberrations while maintaining downsizing of the optical system.

  With the above-described lens group configuration, negative distortion generated in the front group upon zooming from the wide-angle end to the telephoto end is reduced in the second lens group and the third lens group, and field curvature is achieved in the fourth lens group. Can be satisfactorily reduced.

  Further, the second lens group having a positive refractive power can reduce the spherical aberration generated in the front group, and at the same time reduce the variation of the spherical aberration upon zooming from the wide angle end to the telephoto end. it can. As a result, according to this zoom lens, it is possible to facilitate high zooming.

  In addition, it is preferable to arrange a positive lens in both the second lens group and the third lens group to increase the refractive power of the positive lens. By doing in this way, the generation amount of field curvature can be reduced.

  Further, the second lens group or the third lens group has a focus lens group.

  When the focus lens group is disposed in the second lens group or the third lens group, the focus lens group is positioned near the aperture stop near the wide-angle end. Here, the light beam diameter is small in the vicinity of the aperture stop. Therefore, the focus lens group can be arranged at a position where the lens diameter is smaller in the rear group. As a result, the diameter of the focus lens group can be reduced.

  In addition, it is preferable that a focus lens group having a positive refractive power is disposed closer to the object side than the aperture stop, and only the focus lens group moves along the optical axis during focusing. In this way, there is no lens group that moves during focusing on the image side of the aperture stop. Therefore, it is not necessary to secure a predetermined space on the image side from the aperture stop. As a result, it is possible to reduce the diameter of the lens group located on the image side of the aperture stop. The predetermined space is a space necessary for the lens group to move during focusing.

  In addition, it is possible to shoot a wider range with an optical system having an ultra-wide angle of view. In such an optical system, fluctuations in field curvature that occur during focusing may deteriorate imaging performance. In particular, the fluctuation of the curvature of field on the meridional surface may deteriorate the imaging performance when focusing on a short distance object.

  The front group may cause a large curvature of field on the meridional surface. In this case, if the height of the peripheral ray passing through the front group varies during focusing, the variation in field curvature on the meridional surface also increases. In particular, when focusing on a short-distance object, the height of peripheral rays passing through the front group varies greatly.

  Therefore, it is preferable to dispose the focus lens group closer to the object side than the aperture stop. In this way, the focus lens group is positioned closer to the image side than the front group. Here, the height of the peripheral ray is lower on the image side than the front group compared to the front group. Therefore, in the focus lens group, the height of the peripheral rays is reduced.

  In this case, even if the focus lens group moves, fluctuations in the height of the peripheral rays passing through the front group can be reduced. Thereby, the fluctuation | variation of the curvature of field in a meridional surface can also be suppressed. As a result, the imaging performance of the optical system can be kept high even when focusing on a short-distance object.

  The focus sensitivity is affected by the magnification of the focus lens group and the magnification of a predetermined lens group. Here, the predetermined lens group is a lens group located between the image side surface and the image plane of the focus lens group. Therefore, the focus sensitivity can be increased by disposing the focus lens group on the object side of the aperture stop and appropriately setting the magnification of the predetermined lens group. As a result, the amount of movement of the focus lens group can be reduced.

  In addition, since the amount of movement of the focus lens group can be reduced, fluctuations in the height of the peripheral rays in the front group can be reduced during focusing. For this reason, it is possible to suppress the variation in curvature of field on the meridional surface. As a result, the imaging performance of the optical system can be maintained high even when focusing on a short-distance object.

  As a result, good optical performance can be maintained during focusing on a short-distance object. In addition, the focus lens group can be reduced in size and weight. As a result, the focus speed can be increased, and the drive mechanism of the focus lens group can be reduced in weight and space.

  Note that the amount of separation between the axial ray and the peripheral ray is small near the aperture stop. Therefore, it is preferable to arrange the focus lens group near the aperture stop. At this position, the beam diameter of the axial beam is large. When the beam diameter of the axial beam is large, the magnification of the focus lens group can be increased more effectively.

  As described above, when the focus lens group is disposed near the aperture stop, it is possible to focus at a place where the magnification of the focus lens group can be increased more effectively, that is, a place where the axial light beam is thick. Therefore, by focusing at this position, it is possible to reduce the fluctuation in the height of the peripheral rays in the front group while increasing the sensitivity of the focus.

  Next, the preferable aspect in this embodiment is demonstrated.

In the zoom lens according to the first embodiment, it is preferable that the above-described basic configuration is provided and the following conditional expression (9-1) is satisfied.
1.65 <SP _F1 <9.0 (9-1)
here,
SP _F1 = (r _F1o + r _F1i ) / (r _F1o -r _F1i )
r _F1o is the paraxial radius of curvature of the object side of the first lens,
r _F1i is the paraxial radius of curvature of the image side of the first lens,
It is.

  By exceeding the lower limit value of the conditional expression (9-1), it is possible to suppress an excessively large difference in curvature between the object side surface and the image side surface in the first lens. As a result, the amount of astigmatism generated can be reduced.

  By falling below the upper limit value of conditional expression (9-1), it is possible to suppress the difference in curvature between the object side surface and the image side surface from becoming too small in the first lens. In this case, since the refractive power of an appropriate magnitude can be secured in the first lens, the height of the light beam incident on the rear group can be reduced. As a result, the lens diameter of the rear group can be reduced. In addition, since the negative refractive power of the front group can be reduced to some extent, the top of the object side surface can be prevented from being positioned on the object side. As a result, it is possible to shorten the overall length of the optical system and reduce the diameter of the optical system.

The zoom lens according to the second embodiment preferably has the above-described basic configuration and satisfies the following conditional expression (2).
−1.45 <FB _w / f _F <−0.3 (2)
here,
FB _w is the back focus at the wide-angle end,
f _F is the focal length of the front group,
It is.

  By exceeding the lower limit value of conditional expression (2), the back focus at the wide angle end can be shortened. As a result, the optical system can be reduced in size. In addition, since the refractive power of the front group can be suppressed from becoming too large, the amount of field curvature and astigmatism can be reduced.

  Moreover, the refractive power of a front group can be set appropriately by falling below conditional expression (2) upper limit. As a result, the diameter of the optical system can be reduced.

The zoom lens according to the third embodiment preferably includes the above-described basic configuration and satisfies the following conditional expression (1-3).
52 <νd _Fnmax <110 (1-3)
here,
νd _Fnmax is the maximum Abbe number among the Abbe numbers of lenses having negative refractive power included in the front group,
It is.

  By exceeding the lower limit value of the conditional expression (1-3), it is possible to reduce the amount of lateral chromatic aberration generated in the front group. Moreover, the conditional expression (1-3) lower than the upper limit value can ensure a wide degree of freedom in selecting the glass material.

The zoom lens according to the fourth embodiment preferably includes the above-described basic configuration and satisfies the following conditional expression (4).
1.20 <f _Rw / FB _w <5 (4)
here,
f _Rw is the focal length of the rear group at the wide angle end,
FB _w is the back focus at the wide-angle end,
It is.

  By exceeding the lower limit value of the conditional expression (4), it is possible to reduce the generation amount of spherical aberration and longitudinal chromatic aberration while appropriately ensuring the refractive power of the rear group at the wide angle end. In addition, since the back focus at the wide-angle end can be shortened, the overall length of the optical system can be shortened. Furthermore, since the refractive power of the front group can be increased, the diameter of the optical system can be reduced.

  Further, by falling below the upper limit value of the conditional expression (4), it is possible to shorten the overall length of the optical system while appropriately securing the refractive power of the rear group. Further, by increasing the positive refractive power of the rear group, the amount of occurrence of field curvature can be reduced.

  A preferable aspect of the zoom lens according to the first to fourth embodiments will be described. In the following description, the zoom lenses of the first to fourth embodiments are simply referred to as “zoom lenses of this embodiment”.

In the zoom lens according to the present embodiment, it is preferable that the following conditional expression (3-1) is satisfied.
-2.7 <f _w × Fno _wmin / f _F <−0.5 (3-3)
here,
f _w is the focal length of the entire zoom lens system at the wide-angle end,
Fno _wmin is the smallest F number at the wide-angle end,
f _F is the focal length of the front group,
It is.

  By exceeding the lower limit value of the conditional expression (3-3), it is possible to make the angle of view an ultra wide angle of view even though the zoom lens has a small diameter and a small F number. Moreover, a front group can be reduced in diameter by falling below the upper limit of conditional expression (3-3).

  The front group includes a second lens having negative refractive power, the second lens is disposed closer to the image side than the first lens, and has a meniscus shape with a convex surface facing the object side. The shape is preferred.

  By doing so, off-axis rays can be gradually refracted while increasing the negative refractive power in the front group. That is, rapid refraction of light rays can be suppressed. As a result, it is possible to make the angle of view an ultra-wide angle of view while reducing the amount of curvature of field and astigmatism.

  In the zoom lens according to the present embodiment, it is preferable that the front group further includes a fourth lens having a negative refractive power.

  By doing so, it is possible to satisfactorily correct the spherical aberration in the front group, and to suppress the variation of the spherical aberration at the time of zooming. As a result, good optical performance can be obtained over the entire zoom range. In addition, the refractive power of the front group can be increased while suppressing the occurrence of field curvature, astigmatism, and lateral chromatic aberration. As a result, since the entrance pupil is located closer to the object side, the diameter of the front group can be reduced. The front group may further include a lens having negative refractive power. By doing in this way, the above-mentioned effect can be enlarged more.

  Moreover, it is preferable that the lens having negative refractive power is disposed in the vicinity of the lens having positive refractive power. For example, the fourth lens is preferably arranged in the vicinity of the third lens. By doing in this way, the above-mentioned effect can be enlarged more.

  In the zoom lens according to the present embodiment, the front group further includes a fourth lens having negative refractive power, and the shape of the fourth lens is preferably a meniscus shape.

  By doing so, three meniscus lenses are arranged in the front group. In this case, the light beam incident on the front group with an ultra-wide angle of view can be gradually refracted by the three meniscus lenses. Each meniscus lens can gradually refract the light while keeping the angle of the light incident on the lens small. For this reason, in each meniscus lens, the occurrence of curvature of field, astigmatism, and lateral chromatic aberration can be suppressed. The front group may further include a negative meniscus lens. By doing in this way, the above-mentioned effect can be enlarged more.

  In the zoom lens according to the present embodiment, the front group further includes a fourth lens having a negative refractive power, and the shape of the fourth lens may be a meniscus shape having a convex surface facing the object side. preferable.

  By doing so, a negative meniscus lens is arranged in the front group in addition to the first lens and the second lens. Here, all of the three negative meniscus lenses have a convex surface on the object side, that is, a concave surface on the image side. In this case, rapid refraction of light rays can be suppressed while further increasing the negative refractive power of the front group. Therefore, the amount of curvature of field and astigmatism can be reduced. As a result, it becomes easy to further widen the angle of view and reduce the diameter of the optical system. The front group may further include a negative meniscus lens having a convex surface facing the object side. By doing in this way, the above-mentioned effect can be enlarged more.

  In the zoom lens according to the present embodiment, it is preferable that the fourth lens is disposed closer to the image side than the second lens.

  Thereby, the refractive power of the front group can be increased while reducing the amount of occurrence of field curvature, astigmatism, and lateral chromatic aberration. Further, since the entrance pupil is located closer to the object side, the diameter of the front group can be reduced.

In the zoom lens according to the present embodiment, it is preferable that the following conditional expression (5) is satisfied.
1.1 <| r _F1i / f _F | <3 (5)
here,
r _F1i is the paraxial radius of curvature of the image side of the first lens,
f _F is the focal length of the front group,
It is.

  By exceeding the lower limit value of conditional expression (5), it is possible to suppress the refractive power of the first lens from becoming too large. As a result, the amount of curvature of field, astigmatism, and distortion can be reduced. Moreover, since the total thickness of the front group can be reduced, the overall length of the optical system can be shortened.

  By falling below the upper limit value of conditional expression (5), the refractive power of the first lens is increased. In this case, since the lens diameter in the front group becomes small, the optical system can be miniaturized. In addition, the refractive power of the front group can be increased while reducing the amount of curvature of field and astigmatism.

In the zoom lens according to the present embodiment, it is preferable that the following conditional expression (6) is satisfied.
0.53 <θgF _Fn <0.55 (6)
here,
θgF _Fn is a partial dispersion ratio in the lens having the largest Abbe number among the lenses having negative refractive power included in the front group, and θgF _Fn = (ng−nF) / (nF−nc). Represented,
ng, nF, and nc are the refractive indexes of the g-line, F-line, and C-line of the lens having the largest Abbe number,
It is.

  By satisfying conditional expression (6), it is possible to suppress the occurrence of lateral chromatic aberration in the front group while ensuring a wide degree of freedom in selecting the glass material used in the front group.

In the zoom lens according to the present embodiment, it is preferable that the following conditional expression (7) is satisfied.
0.01 <θgF _Fn + 0.0016 × νd−0.6415 <0.054 (7)
here,
θgF _Fn is a partial dispersion ratio in the lens having the largest Abbe number among the lenses having negative refractive power included in the front group, and θgF _Fn = (ng−nF) / (nF−nc). Represented,
ng, nF, and nc are the refractive indexes of the g-line, F-line, and C-line of the lens having the largest Abbe number,
νd is the Abbe number of the lens with the largest Abbe number value,
It is.

  In the front group, a plurality of lenses having negative refractive power are mainly used to suppress the occurrence of field curvature and astigmatism. However, axial chromatic aberration, lateral chromatic aberration, and spherical aberration may be mainly generated by a lens having negative refractive power. Therefore, by arranging a lens having a positive refractive power in the front group, it becomes easy to reduce the amount of occurrence of these aberrations. As a result, it is easy to ensure high optical performance.

  Here, in order to satisfactorily correct the chromatic aberration while increasing the negative refractive power of the front group, it is preferable that the dispersion of the lens having the positive refractive power is high dispersion. However, if the dispersion of a lens having a positive refractive power is high, a secondary spectrum may be greatly generated. Therefore, it is effective for correction of chromatic aberration to use a glass material having a characteristic capable of reducing the generation amount of the secondary spectrum for the lens having negative refractive power in the front group.

  By exceeding the lower limit value of conditional expression (7), it is possible to reduce the amount of secondary spectrum generated in the front group. As a result, the amount of axial chromatic aberration and lateral chromatic aberration generated can be reduced.

  By falling below the upper limit value of conditional expression (7), it is possible to suppress the amount of secondary spectrum generated in the front group from being overcorrected. As a result, it is possible to balance axial chromatic aberration and lateral chromatic aberration.

In the zoom lens according to the present embodiment, it is preferable that the following conditional expression (8) is satisfied.
0.06 <FB _w / LTL _w <0.20 (8)
here,
FB _w is the back focus at the wide-angle end,
LTL _w is the axial distance from the most object-side surface of the zoom lens to the image plane at the wide-angle end.

  By exceeding the lower limit value of conditional expression (8), the total length of the optical system can be shortened with respect to the back focus at the wide-angle end. As a result, the overall length of the optical system can be shortened. The on-axis distance is a paraxial distance.

  By falling below the upper limit value of conditional expression (8), the back focus can be shortened with respect to the entire length of the optical system at the wide-angle end. As a result, the overall length of the optical system can be shortened. In addition, when an optical element is arranged in the optical system, a sufficient space for arranging the optical element can be secured. Therefore, it becomes easy to ensure high optical performance over the entire zoom range.

In the zoom lens according to the present embodiment, at least one of the meniscus lenses in the front group having a convex surface facing the object side satisfies the following conditional expression (10). It preferably has a spherical surface.
30 ° <ASP _R θ <70 ° (10)
here,
ASP _R θ is the inclination of the surface at a predetermined position on the image side surface of at least one lens,
The predetermined position is a position where the effective aperture is maximum in at least one lens,
The inclination of the surface is the angle at which the tangent of the surface and the optical axis intersect at a given position,
It is.

  By exceeding the lower limit value of conditional expression (10), it is possible to reduce the amount of astigmatism and distortion. When the upper limit of conditional expression (10) is not reached, the amount of chromatic aberration of magnification can be reduced.

  In the zoom lens according to the present embodiment, it is preferable that the front group moves during zooming.

  Thereby, the amount of curvature of field can be reduced over the entire zoom range.

  In the zoom lens according to the present embodiment, the second lens group or the third lens group includes a camera shake reduction lens unit, and the camera shake reduction lens unit is moved in a direction perpendicular to the optical axis, thereby causing camera shake. It is preferable to reduce image blur.

  Image blur occurs due to camera shake. Therefore, image blur correction is performed by moving the camera shake reduction lens unit in a direction perpendicular to the optical axis. By doing so, the magnification of the camera shake reduction lens unit can be increased. That is, the amount of movement of the image can be made larger than the amount of movement of the camera shake reduction lens unit. As a result, camera shake reduction sensitivity can be increased.

  In addition, it is preferable that the second lens group includes a camera shake reduction lens unit, and the image blur due to camera shake is reduced by moving the camera shake reduction lens unit in a direction perpendicular to the optical axis.

  As described above, the front group has a negative refractive power. Therefore, a camera shake reduction unit is disposed on the image side of the front group, and the second group having the camera shake reduction lens unit has a positive refractive power. As a result, the sensitivity for reducing camera shake can be further increased.

  The second lens group is a camera shake reduction lens unit, and it is preferable to reduce image blur due to camera shake by moving the camera shake reduction lens unit in a direction perpendicular to the optical axis.

  As a result, it is possible to reduce the occurrence of tilt errors in the camera shake reduction lens unit and to secure more stable performance.

  In addition, it is preferable that the third lens group includes a camera shake reduction lens unit, and the image blur due to camera shake is reduced by moving the camera shake reduction lens unit in a direction perpendicular to the optical axis.

  The third lens group is a camera shake reduction lens unit, and it is preferable to reduce image blur due to camera shake by moving the camera shake reduction lens unit in a direction perpendicular to the optical axis.

  As a result, it is possible to reduce the occurrence of tilt errors in the camera shake reduction lens unit and to secure more stable performance.

  In the zoom lens according to the present embodiment, it is preferable that the camera shake reduction lens unit is disposed closer to the image side than the focus lens group.

  It is preferable that the camera shake reduction lens unit can move at a higher speed. Further, it is preferable that the moving range is narrow. For that purpose, it is desirable that the diameter of the camera shake reduction lens unit be as small as possible. That is, it is desirable that a lens (lens unit) at a position where the light beam is thinner be a camera shake reduction lens unit.

  The light beam emitted from the focus lens group passes through the aperture stop. Therefore, the beam diameter is smaller on the image side than the focus lens group. Therefore, by arranging the camera shake reduction lens unit here, the diameter of the camera shake reduction lens unit can be reduced. As a result, image blur can be reduced more favorably.

  In the zoom lens according to the present embodiment, it is preferable that the camera shake reduction lens unit has a negative refractive power.

  As a result, the camera shake reduction lens unit is positioned in a portion where the luminous flux is narrower. As a result, the diameter and movement range of the camera shake reduction lens unit can be reduced.

In the zoom lens according to the present embodiment, it is preferable that the following conditional expression (11) is satisfied.
−25 <DTL _w <7 (11)
here,
DTL _w is distortion at the maximum angle of view at the wide-angle end, and is expressed by DTL _w = (IH _w1 −IH _w2 ) / IH _w2 × 100 (%),
IH _w1 is the real image height at which the maximum field angle at the wide-angle end from the infinite object point is imaged on the image plane,
IH _w2 is the paraxial image height at which the maximum field angle at the wide-angle end from the infinite object point is imaged on the image plane,
It is.

  By appropriately setting the amount of distortion, the optical system can be reduced in diameter while increasing the refractive power of the front group to increase the super wide angle of view and shorten the total length of the optical system.

  By exceeding the lower limit value of conditional expression (11), the amount of barrel distortion can be reduced. As a result, the perspective effect can be strengthened. In addition, when distortion is electrically corrected, the image in the peripheral portion of the image may be greatly stretched to deteriorate the image, but this deterioration can be suppressed.

  By falling below the upper limit value of conditional expression (11), the diameter of the front group can be reduced. As a result, the optical system can be reduced in size.

The zoom lens according to the present embodiment includes a predetermined lens group, and the predetermined lens group is a lens group located between the image side surface and the image plane of the focus lens group, and the following conditional expression ( It is preferable to satisfy 12).
0.10 <| MG _fob ² × (MG _fo ² −1) | <3.0 (12)
here,
MG _fo is the lateral magnification of the focus lens group at an arbitrary position,
MG _fob is a lateral magnification of a predetermined lens group at the same position as an arbitrary position,
It is.

  By exceeding the lower limit value of conditional expression (12), the amount of movement of the focus lens group can be reduced. As a result, the overall length of the optical system can be shortened. By falling below the upper limit value of conditional expression (12), the position control of the focus lens group can be easily performed. As a result, accurate focusing can be achieved.

In the zoom lens according to the present embodiment, it is preferable that the following conditional expression (13) is satisfied.
−2.0 <f _F / (f _w × f _t ) ^1/2 <−1.0 (13)
f _F is the focal length of the front group,
f _w is the focal length of the entire zoom lens system at the wide angle end,
f _t is the focal length of the entire zoom lens system at the telephoto end,
It is.

  Conditional expression (13) relates to the ratio between the focal length of the front group and the product of the focal lengths at the wide-angle end and the telephoto end.

  By exceeding the lower limit value of conditional expression (13), it is possible to suppress the refractive power of the front group from becoming too large. As a result, the amount of astigmatism and lateral chromatic aberration generated at the wide angle end can be reduced.

  By falling below the upper limit value of conditional expression (13), the refractive power of the front group can be increased appropriately, so that the entrance pupil can be positioned closer to the object side. As a result, the diameter of the front group can be reduced.

In the zoom lens according to the present embodiment, it is preferable that the following conditional expression (14) is satisfied.
1.6 <SP _F2 <6 (14)
here,
SP _F2 = (r _F2o + r _F2i ) / (r _F2o -r _F2i )
r _F2o is the paraxial radius of curvature of the object side of the second lens,
r _F2i is the paraxial radius of curvature of the image side surface of the second lens,
It is.

  By exceeding the lower limit value of the conditional expression (14), the total length of the optical system can be shortened with respect to the back focus at the wide angle end. As a result, the overall length of the optical system can be shortened.

  By falling below the upper limit value of conditional expression (14), the back focus can be shortened with respect to the entire length of the optical system at the wide-angle end. As a result, the overall length of the optical system can be shortened. Further, when an optical element is arranged in the optical system, it becomes easy to secure a sufficient space for arranging the optical element. For this reason, the optical performance in the entire zoom range can be improved.

  The second lens group preferably has a focus lens group.

  The third lens group preferably has a focus lens group.

In the zoom lens according to the present embodiment, it is preferable that the following conditional expression (15-1) is satisfied.
0.3 <SP _F4 <4.5 (15-1)
here,
SP _F4 = (r _F4o + r _F4i ) / (r _F4o -r _F4i )
r _F4o is the paraxial radius of curvature of the object side surface of the fourth lens,
r _F4i is the paraxial radius of curvature of the image side of the fourth lens,
It is.

  By exceeding the lower limit of conditional expression (15-1), the total length of the optical system can be shortened with respect to the back focus at the wide-angle end. As a result, the overall length of the optical system can be further shortened.

  By falling below the upper limit value of conditional expression (15-1), the back focus can be shortened with respect to the entire length of the optical system at the wide-angle end. As a result, the overall length of the optical system can be further shortened. Further, when an optical element is arranged in the optical system, it becomes easy to secure a sufficient space for arranging the optical element. For this reason, the optical performance in the entire zoom range can be improved.

  In the zoom lens according to the present embodiment, it is preferable that the focus lens group is disposed on the most object side of the rear group.

  Since the rear group has an aperture stop, the height of the peripheral rays is lower at the position of the aperture stop than in the front group. Therefore, by arranging the focus lens group on the most object side of the rear group, the height of the peripheral light beam is lowered in the focus lens group.

  In this case, even if the focus lens group moves, fluctuations in the height of the peripheral rays passing through the front group can be reduced. Thereby, the fluctuation | variation of the curvature of field in a meridional surface can also be suppressed. As a result, the imaging performance of the optical system can be kept high even when focusing on a short-distance object.

  In the zoom lens according to the present embodiment, it is preferable that the lens group located closest to the image side has a positive refractive power.

  It is necessary to increase the refractive power of the front group in order to increase the angle of view, to reduce the size of the optical system, and to reduce the diameter of the optical system. Positive field curvature occurs. Therefore, by arranging a lens group having a positive refractive power closest to the image side, a large positive field curvature that occurs in the front group can be easily corrected. As a result, it is possible to ensure a state in which the field curvature is favorably corrected over the entire zoom range.

  In the zoom lens according to the present embodiment, the front group includes the first lens group, and it is preferable that the first lens group move as a unit when zooming from the wide-angle end to the telephoto end.

  By doing so, it is not necessary to provide a space necessary for zooming in the front group. Therefore, the front group can be reduced in size.

  If the moving direction and moving amount are different for each lens, it may be necessary to provide an extra space necessary for moving the lens. As a result, the total length of the front group may change. On the other hand, when the front group moves together, all the lenses in the front group move by the same amount in the same direction. In this case, the total length of the previous group does not change. Therefore, the front group can be reduced in size by doing in this way.

  In the zoom lens according to the present embodiment, the front group includes the first lens group, and the rear group includes the second lens group, the third lens group, the fourth lens group, and the fifth lens group. Or the rear group includes a second lens group, a third lens group, a fourth lens group, a fifth lens group, and a sixth lens group, and changes from the wide-angle end to the telephoto end. At the time of magnification, it is preferable that the interval between the lens groups changes.

  This makes it possible to reduce the size and weight of the optical system sufficiently with a small number of lens groups, and to have various aberrations sufficiently reduced while having a sufficiently wide angle of view compared to the F-number. A lens can be realized.

  In the zoom lens according to the present embodiment, it is preferable to do the following.

  The front group preferably includes four lenses having negative refractive power and one lens having positive refractive power.

  The front group has, in order from the object side to the image side, two meniscus lenses having negative refractive power and a convex surface facing the object side, and one lens having negative refractive power; It is preferable to consist of two lenses.

  The front group has negative refractive power in order from the object side to the image side, and has positive meniscus-shaped three lenses with a convex surface facing the object side, a biconcave negative lens, and positive refractive power. In addition, the lens preferably has a lens whose object side surface is convex toward the object side.

  The fourth lens group preferably comprises only a biconcave negative lens.

  In zooming from the wide-angle end to the telephoto end, it is preferable that the front group moves to the image side.

  In zooming from the wide-angle end to the telephoto end, it is preferable that the second lens group moves to the object side.

  In zooming from the wide-angle end to the telephoto end, it is preferable that the third lens group moves to the object side.

  In zooming from the wide-angle end to the telephoto end, it is preferable that the fourth lens group moves to the object side.

  The image pickup apparatus according to the present embodiment includes the zoom lens described above and an image pickup element that has an image pickup surface and converts an image formed on the image pickup surface by the zoom lens into an electric signal.

  By doing so, it is possible to provide an imaging device that is advantageous in obtaining a high-resolution image without deteriorating the image quality, while having an ultra-wide angle of view and a small size.

  In addition, it is more preferable that a plurality of the above-described configurations satisfy each other simultaneously. Moreover, you may make it satisfy some structures simultaneously. For example, any of the above zoom lenses may be used in any of the above zoom lenses or imaging devices.

  Further, regarding the conditional expressions, each conditional expression may be satisfied individually. This is preferable because each effect can be easily obtained.

  Further, for each conditional expression, the lower limit value or the upper limit value may be changed as follows. This is preferable because the effect of each conditional expression can be further ensured.

The conditional expression (1-3) is preferably as follows.
74 <νd _Fnmax <110
80 <νd _Fnmax <100
Conditional expression (2) is preferably as follows.
−1.40 <FB _w / f _F <−0.4
−1.35 <FB _w / f _F <−0.6
The conditional expression (2-1) is preferably as follows.
−1.50 <FB _w / f _F <−0.5
−1.40 <FB _w / f _F <−0.6
The conditional expression (3-3) is preferably as follows.
-2.30 <f _w × Fno _wmin / f _F <−0.6
−1.80 <f _w × Fno _wmin / f _F <−0.7
−2.00 <f _w × Fno _wmin /f<−1.0
−1.80 <f _w × Fno _wmin /f<−1.2
Conditional expression (4) is preferably as follows.
1.35 <f _Rw / FB _w <3.5
1.45 <f _Rw / FB _w <3.0
Conditional expression (5) is preferably as follows.
1.2 <| r _F1i / f _F | <2.5
1.3 <| r _F1i / f _F | <2.4
Conditional expression (7) is preferably as follows.
0.015 <θgF _Fn + 0.0016 × νd−0.6415 <0.048
0.025 <θgF _Fn + 0.0016 × νd−0.6415 <0.046
Conditional expression (8) is preferably as follows.
0.07 <FB _w / LTL _w <0.18
0.08 <FB _w / LTL _w <0.16
The conditional expression (9-1) is preferably as follows.
2.0 <SP _F1 <6.5
2.5 <SP _F1 <5.3
Conditional expression (10) is preferably as follows.
33 ° <ASP _R θ <60 °
35 ° <ASP _R θ <58 °
Conditional expression (11) is preferably as follows.
−23 <DTL _w <6
−20 <DTL _w <5
Conditional expression (12) is preferably as follows.
0.11 <| MG _fob ² × (MG _fo ² −1) | <2.0
0.15 <| MG _fob ² × (MG _fo ² −1) | <1.5
Conditional expression (13) is preferably as follows.
−1.9 <f _F / (f _w × f _t ) ^1/2 <−1.1
−1.8 <f _F / (f _w × f _t ) ^1/2 <−1.2
−1.7 <f _F / (f _w × f _t ) ^1/2 <−1.2
Conditional expression (14) is preferably as follows.
1.7 <SP _F2 <5.5
1.9 <SP _F2 <5.5
The conditional expression (15-1) is preferably as follows.
0.9 <SP _F4 <5.0
1.0 <SP _F4 <4.0

  Hereinafter, embodiments of a zoom lens used in an imaging apparatus according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  In each embodiment, image recording and display are performed after electrically correcting barrel distortion generated on the wide-angle side. In the zoom lens of this embodiment, an image is formed on a rectangular photoelectric conversion surface. Here, barrel distortion occurs at the wide-angle end. On the other hand, the occurrence of distortion is suppressed near the intermediate focal length state and at the telephoto end.

  In order to electrically correct this distortion, the effective imaging region is set so that it has a barrel shape at the wide-angle end and a rectangular shape at the intermediate focal length state and the telephoto end. Then, the image information in the effective imaging area set in advance is converted by image processing into rectangular image information with reduced distortion.

  In the zoom lens of this embodiment, the maximum image height at the wide-angle end is made smaller than the maximum image at the intermediate focal length state and the maximum image height at the telephoto end.

  Examples 1 to 6 of the zoom lens will be described below. Lens sectional views of Examples 1 to 6 are shown in FIGS. 1 to 6, respectively. In the drawing, (a) is a lens sectional view at the wide-angle end, (b) is a lens sectional view at an intermediate focal length state, and (c) is a lens sectional view at the telephoto end. Note that (a) to (c) are all lens cross-sectional views when focusing on an object at infinity.

  The first lens group is G1, the second lens group is G2, the third lens group is G3, the fourth lens group is G4, the fifth lens group is G5, the sixth lens group is G6, the focus lens group is Gfo, The aperture stop (brightness stop) is indicated by S, and the image plane (imaging surface) is indicated by I. Further, F represents a lens group that moves during focusing, and W represents a lens that moves during camera shake correction.

Note that a parallel plate constituting a low-pass filter or a cover glass of an electronic image sensor may be disposed between the lens group located closest to the image side and the image plane I. In this case, a wavelength region limiting coat that limits infrared light may be applied to the surface of the parallel plate. Moreover, you may give the multilayer film for wavelength range limitation to the surface of a cover glass. Further, the cover glass may have a low-pass filter action.
As shown in FIG. 1, the zoom lens according to the first exemplary embodiment includes, in order from the object side to the image side, a front group GF having a negative refractive power and a rear group GR having a positive refractive power. The rear group GR includes a focus lens group Gfo having a positive refractive power. The focus lens group Gfo is located closer to the object side than the aperture stop S.

  More specifically, the zoom lens includes, in order from the object side to the image side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group G3 having a positive refractive power. The fourth lens group G4 has a negative refractive power and the fifth lens group G5 has a positive refractive power. The aperture stop S is disposed on the object side of the third lens group G3.

  The first lens group G1 includes a negative meniscus lens L1 having a convex surface facing the object side, a negative meniscus lens L2 having a convex surface facing the object side, a negative meniscus lens L3 having a convex surface facing the object side, and a biconcave negative lens. L4 and a positive meniscus lens L5 having a convex surface facing the object side. Here, the biconcave negative lens L4 and the positive meniscus lens L5 are cemented.

  The second lens group G2 includes a positive meniscus lens L6 having a convex surface directed toward the object side.

  The third lens group G3 includes a negative meniscus lens L7 having a convex surface directed toward the object side, a biconvex positive lens L8, a biconcave negative lens L9, a biconvex positive lens L10, a biconvex positive lens L11, and a biconvex lens. It consists of a positive lens L12. Here, the negative meniscus lens L7 and the biconvex positive lens L8 are cemented. The biconcave negative lens L9 and the biconvex positive lens L10 are cemented.

  The fourth lens group G4 includes a biconcave negative lens L13.

  The fifth lens group G5 includes a biconvex positive lens L14.

  At the time of zooming from the wide-angle end to the telephoto end, each lens unit moves as follows. The first lens group G1 moves to the image side. The second lens group G2 moves to the object side. The third lens group G3 moves to the object side. The fourth lens group G4 moves to the object side. The fifth lens group G5 is fixed. The aperture stop S moves to the object side together with the third lens group G3.

  At the time of focusing, the second lens group G2 moves along the optical axis. More specifically, the second lens group G2 moves to the image side when focusing from an object at infinity to an object at a short distance. At the time of camera shake correction, the negative meniscus lens L7 and the biconvex positive lens L8 of the third lens group G3 move in the direction orthogonal to the optical axis.

  The aspheric surfaces are provided on a total of eight surfaces including both surfaces of the negative meniscus lens L3, both surfaces of the positive meniscus lens L6, both surfaces of the biconvex positive lens L12, and both surfaces of the biconvex positive lens L14.

  The front group GF includes a first lens group G1. The rear group GR includes a second lens group G2, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. The focus lens group Gfo includes a second lens group G2.

  As shown in FIG. 2, the zoom lens according to the second exemplary embodiment includes, in order from the object side to the image side, a front group GF having a negative refractive power and a rear group GR having a positive refractive power. The rear group GR includes a focus lens group Gfo having a positive refractive power. The focus lens group Gfo is located closer to the object side than the aperture stop S.

  More specifically, the zoom lens includes, in order from the object side to the image side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group G3 having a positive refractive power. The fourth lens group G4 having negative refractive power, the fifth lens group G5 having positive refractive power, and the sixth lens group G6 having negative refractive power. The aperture stop S is disposed on the object side of the third lens group G3.

  The first lens group G1 includes a negative meniscus lens L1 having a convex surface facing the object side, a negative meniscus lens L2 having a convex surface facing the object side, a negative meniscus lens L3 having a convex surface facing the object side, and a biconcave negative lens. L4 and a biconvex positive lens L5.

  The second lens group G2 includes a negative meniscus lens L6 having a convex surface directed toward the object side, and a biconvex positive lens L7. Here, the negative meniscus lens L6 and the biconvex positive lens L7 are cemented.

  The third lens group G3 is composed of a biconvex positive lens L8.

  The fourth lens group G4 includes a biconvex positive lens L9 and a biconcave negative lens L10.

  The fifth lens group G5 includes a negative meniscus lens L11 having a convex surface directed toward the object side, a negative meniscus lens L12 having a convex surface directed toward the object side, a positive meniscus lens L13 having a convex surface directed toward the object side, and a biconvex positive lens L14. Here, the negative meniscus lens L12 and the positive meniscus lens L13 are cemented.

  The sixth lens group G6 includes a biconcave negative lens L15 and a biconvex positive lens L16. Here, the biconcave negative lens L15 and the biconvex positive lens L16 are cemented.

  At the time of zooming from the wide-angle end to the telephoto end, each lens unit moves as follows. The first lens group G1 moves to the image side. The second lens group G2 moves to the object side. The third lens group G3 moves to the object side. The fourth lens group G4 moves to the object side. The fifth lens group G5 moves to the object side. The sixth lens group G6 moves to the object side. The aperture stop S moves to the object side together with the third lens group G3.

  At the time of focusing, the second lens group G2 moves along the optical axis. More specifically, the second lens group G2 moves to the image side when focusing from an object at infinity to an object at a short distance. At the time of camera shake correction, the third lens group G3 moves in a direction orthogonal to the optical axis.

  The aspheric surfaces are provided on a total of four surfaces including both surfaces of the negative meniscus lens L2, the image side surface of the negative meniscus lens L3, and the image side surface of the biconvex positive lens L16.

  The front group GF includes a first lens group G1. The rear group GR includes a second lens group G2, a third lens group G3, a fourth lens group G4, a fifth lens group G5, and a sixth lens group G6. The first lens unit LU1 includes a second lens group G2 and a third lens group G3. The focus lens group Gfo includes a second lens group G2.

  As shown in FIG. 3, the zoom lens according to the third exemplary embodiment includes, in order from the object side to the image side, a front group GF having a negative refractive power and a rear group GR having a positive refractive power. The rear group GR includes a focus lens group Gfo having a positive refractive power. The focus lens group Gfo is located closer to the object side than the aperture stop S.

  More specifically, the zoom lens includes, in order from the object side to the image side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group G3 having a positive refractive power. The fourth lens group G4 has a negative refractive power and the fifth lens group G5 has a positive refractive power. The aperture stop S is disposed on the object side of the third lens group G3.

  The first lens group G1 includes a negative meniscus lens L1 having a convex surface facing the object side, a negative meniscus lens L2 having a convex surface facing the object side, a biconcave negative lens L3, and a positive meniscus lens having a convex surface facing the object side. L4.

  The second lens group G2 is composed of a biconvex positive lens L5.

  The third lens group G3 includes a biconcave negative lens L6 and a biconvex positive lens L7.

  The fourth lens group G4 includes a biconcave negative lens L8.

  The fifth lens group G5 includes a biconvex positive lens L9, a negative meniscus lens L10 having a convex surface directed toward the object side, a positive meniscus lens L11 having a convex surface directed toward the object side, a biconvex positive lens L12, and a biconcave negative lens. The lens L13, a biconvex positive lens L14, and a negative meniscus lens L15 having a convex surface facing the image side. Here, the negative meniscus lens L10 and the positive meniscus lens L11 are cemented. A biconcave negative lens L13, a biconvex positive lens L14, and a negative meniscus lens L15 are cemented.

  At the time of zooming from the wide-angle end to the telephoto end, each lens unit moves as follows. The first lens group G1 moves to the image side. The second lens group G2 moves to the image side and then moves to the object side. The third lens group G3 moves to the object side. The fourth lens group G4 moves to the object side. The fifth lens group G5 moves to the object side. The aperture stop S is fixed.

  At the time of focusing, the second lens group G2 moves along the optical axis. More specifically, the second lens group G2 moves to the image side when focusing from an object at infinity to an object at a short distance. At the time of camera shake correction, the negative meniscus lens L6 of the third lens group G3 moves in a direction orthogonal to the optical axis.

  The aspheric surfaces are provided on a total of seven surfaces including both surfaces of the negative meniscus lens L2, both surfaces of the biconvex positive lens L5, both surfaces of the biconvex positive lens L9, and the image side surface of the negative meniscus lens L15.

  The front group GF includes a first lens group G1. The rear group GR includes a second lens group G2, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. The focus lens group Gfo includes a second lens group G2.

  As shown in FIG. 4, the zoom lens according to the fourth exemplary embodiment includes, in order from the object side to the image side, a front group GF having a negative refractive power and a rear group GR having a positive refractive power. The rear group GR includes a focus lens group Gfo having a positive refractive power. The focus lens group Gfo is located closer to the object side than the aperture stop S.

  More specifically, the zoom lens includes, in order from the object side to the image side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group G3 having a positive refractive power. The fourth lens group G4 has a negative refractive power and the fifth lens group G5 has a positive refractive power. The aperture stop S is disposed on the object side of the third lens group G3.

  The first lens group G1 includes a negative meniscus lens L1 having a convex surface facing the object side, a negative meniscus lens L2 having a convex surface facing the object side, a negative meniscus lens L3 having a convex surface facing the object side, and a biconcave negative lens. L4 and a positive meniscus lens L5 having a convex surface facing the object side.

  The second lens group G2 includes a positive meniscus lens L6 having a convex surface directed toward the object side.

  The third lens group G3 includes a negative meniscus lens L7 having a convex surface directed toward the object side, a biconvex positive lens L8, a biconcave negative lens L9, a positive meniscus lens L10 having a convex surface directed toward the object side, and a biconvex positive The lens L11 and a positive meniscus lens L12 having a convex surface facing the image side. Here, the negative meniscus lens L7 and the biconvex positive lens L8 are cemented. The biconcave negative lens L9 and the positive meniscus lens L10 are cemented.

  The fourth lens group G4 includes a biconvex positive lens L13 and a biconcave negative lens L14. Here, the biconvex positive lens L13 and the biconcave negative lens L14 are cemented.

  The fifth lens group G5 is composed of a biconvex positive lens L15.

  At the time of zooming from the wide-angle end to the telephoto end, each lens unit moves as follows. The first lens group G1 moves to the image side. The second lens group G2 moves to the object side. The third lens group G3 moves to the object side. The fourth lens group G4 moves to the object side. The fifth lens group G5 is fixed. The aperture stop S moves to the object side together with the third lens group G3.

  At the time of focusing, the second lens group G2 moves along the optical axis. More specifically, the second lens group G2 moves to the image side when focusing from an object at infinity to an object at a short distance. At the time of camera shake correction, the negative meniscus lens L7 and the biconvex positive lens L8 of the third lens group G3 move in the direction orthogonal to the optical axis.

  The aspheric surfaces are provided on a total of eight surfaces including both surfaces of the negative meniscus lens L3, both surfaces of the positive meniscus lens L6, both surfaces of the biconvex positive lens L11, and both surfaces of the biconvex positive lens L15.

  The front group GF includes a first lens group G1. The rear group GR includes a second lens group G2, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. The focus lens group Gfo includes a second lens group G2.

  As shown in FIG. 5, the zoom lens according to the fifth exemplary embodiment includes, in order from the object side to the image side, a front group GF having a negative refractive power and a rear group GR having a positive refractive power. The rear group GR includes a focus lens group Gfo having a positive refractive power. The focus lens group Gfo is located closer to the object side than the aperture stop S.

  More specifically, the zoom lens includes, in order from the object side to the image side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group G3 having a positive refractive power. The fourth lens group G4 has a negative refractive power and the fifth lens group G5 has a positive refractive power. The aperture stop S is disposed on the object side of the third lens group G3.

  The first lens group G1 includes a negative meniscus lens L1 having a convex surface facing the object side, a negative meniscus lens L2 having a convex surface facing the object side, a negative meniscus lens L3 having a convex surface facing the object side, and a biconcave negative lens. L4 and a positive meniscus lens L5 having a convex surface facing the object side. Here, the biconcave negative lens L4 and the positive meniscus lens L5 are cemented.

  The second lens group G2 includes a positive meniscus lens L6 having a convex surface directed toward the object side.

  The third lens group G3 includes a negative meniscus lens L7 having a convex surface directed toward the object side, a biconvex positive lens L8, a biconcave negative lens L9, a positive meniscus lens L10 having a convex surface directed toward the object side, and a biconvex positive The lens L11 includes a biconvex positive lens L12. Here, the negative meniscus lens L7 and the biconvex positive lens L8 are cemented. The biconcave negative lens L9 and the positive meniscus lens L10 are cemented.

  The fourth lens group G4 includes a biconcave negative lens L13.

  The fifth lens group G5 includes a biconvex positive lens L14.

  At the time of zooming from the wide-angle end to the telephoto end, each lens unit moves as follows. The first lens group G1 moves to the image side. The second lens group G2 moves to the object side. The third lens group G3 moves to the object side. The fourth lens group G4 moves to the object side. The fifth lens group G5 moves to the object side. The aperture stop S moves to the object side together with the third lens group G3.

  At the time of focusing, the second lens group G2 moves along the optical axis. More specifically, the second lens group G2 moves to the image side when focusing from an object at infinity to an object at a short distance.

  The aspheric surfaces are provided on a total of eight surfaces including both surfaces of the negative meniscus lens L3, both surfaces of the positive meniscus lens L6, both surfaces of the biconvex positive lens L12, and both surfaces of the biconvex positive lens L14.

  The front group GF includes a first lens group G1. The rear group GR includes a second lens group G2, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. The focus lens group Gfo includes a second lens group G2.

  As shown in FIG. 5, the zoom lens according to the sixth exemplary embodiment includes, in order from the object side to the image side, a front group GF having a negative refractive power and a rear group GR having a positive refractive power. The rear group GR includes a focus lens group Gfo having a positive refractive power. The focus lens group Gfo is located closer to the image side than the aperture stop S.

  More specifically, the zoom lens includes, in order from the object side to the image side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group G3 having a positive refractive power. The fourth lens group G4 has a negative positive refractive power, the fifth lens group G5 has a positive refractive power, and the sixth lens group G6 has a negative positive refractive power. The aperture stop S is disposed on the object side of the third lens group G3.

  The first lens group G1 includes a negative meniscus lens L1 having a convex surface facing the object side, a negative meniscus lens L2 having a convex surface facing the object side, a negative meniscus lens L3 having a convex surface facing the object side, and a biconcave negative lens. L4 and a biconvex positive lens L5.

  The second lens group G2 includes a negative meniscus lens L6 having a convex surface directed toward the object side, and a biconvex positive lens L7. Here, the negative meniscus lens L6 and the biconvex positive lens L7 are cemented.

  The third lens group G3 is composed of a biconvex positive lens L8.

  The fourth lens group G4 includes a biconvex positive lens L9 and a biconcave negative lens L10.

  The fifth lens group G5 includes a negative meniscus lens L11 having a convex surface directed toward the object side, a negative meniscus lens L12 having a convex surface directed toward the object side, a positive meniscus lens L13 having a convex surface directed toward the object side, and a biconvex positive lens L14. Here, the negative meniscus lens L12 and the positive meniscus lens L13 are cemented.

  The sixth lens group G6 includes a biconcave negative lens L15 and a biconvex positive lens L16. Here, the biconcave negative lens L15 and the biconvex positive lens L16 are cemented.

  At the time of zooming from the wide-angle end to the telephoto end, each lens unit moves as follows. The first lens group G1 moves to the image side. The second lens group G2 moves to the object side. The third lens group G3 moves to the object side. The fourth lens group G4 moves to the object side. The fifth lens group G5 moves to the object side. The sixth lens group G6 moves to the object side. The aperture stop S moves to the object side together with the third lens group G3.

  At the time of focusing, the third lens group G3 moves along the optical axis. More specifically, the third lens group G3 moves to the object side when focusing from an object at infinity to an object at a short distance. At the time of camera shake correction, the second lens group G2 moves in a direction orthogonal to the optical axis.

  The aspheric surfaces are provided on a total of four surfaces including both surfaces of the negative meniscus lens L2, the image side surface of the negative meniscus lens L3, and the image side surface of the biconvex positive lens L16.

  The front group GF includes a first lens group G1. The rear group GR includes a second lens group G2, a third lens group G3, a fourth lens group G4, a fifth lens group G5, and a sixth lens group G6. The focus lens group Gfo includes a third lens group G3.

  Below, the numerical data of each said Example are shown. Symbols are the above, r is the radius of curvature of each lens surface, d is the distance between the lens surfaces, nd is the refractive index of the d-line of each lens, νd is the Abbe number of each lens, and * is an aspherical surface . F is the focal length of the entire system, FNO. Is the F number, ω is the half field angle, IH is the image height, FB is the back focus, and the total length is the distance from the lens surface closest to the object side to the lens surface closest to the image side of the zoom lens. F1, f2,... Are focal lengths of the respective lens groups. Note that FB represents the distance from the final lens surface to the paraxial image plane in terms of air. The wide angle represents the wide angle end, the middle represents the intermediate focal length state, and the telephoto represents the telephoto end.

Further, the aspherical shape is expressed by the following equation when the optical axis direction is z, the direction orthogonal to the optical axis is y, the conical coefficient is k, and the aspherical coefficients are A4, A6, A8, and A10. .
z = (y ² / r) / [1+ {1− (1 + k) (y / r) ² } ^1/2 ]
+ A4y ⁴ + A6y ⁶ + A8y ⁸ + A10y ¹⁰
In the aspheric coefficient, “e−n” (n is an integer) indicates “10 ⁻ⁿ ”. The symbols of these specification values are common to the numerical data of the examples described later.

Numerical example 1
Unit mm

Surface data Surface number rd nd νd
Object ∞ ∞
1 41.534 2.70 1.88300 40.80
2 22.807 4.64
3 27.509 2.50 1.88300 40.80
4 18.423 3.24
5 * 22.194 2.50 1.80610 40.88
6 * 12.308 11.39
7 -52.674 1.70 1.43700 95.10
8 28.150 4.17 1.80610 33.27
9 176.442 Variable
10 * 15.571 4.00 1.80610 40.88
11 * 20.314 Variable
12 (Aperture) ∞ 1.25
13 37.996 0.75 1.67300 38.15
14 25.377 2.82 1.49700 81.54
15 -21.144 2.93
16 -12.171 0.80 1.51633 64.14
17 12.171 3.09 1.49700 81.54
18 -2449.791 0.15
19 22.985 4.06 1.43700 95.10
20 -17.837 0.15
21 * 42.216 3.00 1.49700 81.61
22 * -22.203 variable
23 -222.327 0.80 1.90366 31.32
24 17.758 Variable
25 * 33.753 3.81 1.51633 64.06
26 * -38.501 14.74
Image plane ∞

Aspheric data 5th surface
k = 0.000
A4 = 5.37803e-05, A6 = -3.98313e-07, A8 = 1.09495e-09, A10 = -1.05283e-12
6th page
k = -0.478
A4 = 4.93152e-05, A6 = -5.07624e-07, A8 = -1.02107e-09, A10 = 1.42456e-11, A12 = -3.67902e-14
10th page
k = 0.000
A4 = 4.49075e-05, A6 = 3.50017e-07, A8 = -1.81083e-10, A10 = 3.28059e-11
11th page
k = 2.202
A4 = 6.05422e-05, A6 = 8.77251e-07, A8 = -9.79817e-09, A10 = 1.99367e-10
21st page
k = 0.000
A4 = -5.69423e-05, A6 = 7.11500e-08, A8 = -6.67964e-09, A10 = 1.99900e-11
22nd page
k = 0.000
A4 = 2.96556e-05, A6 = 1.35880e-07, A8 = -6.35669e-09, A10 = 3.90872e-11
25th page
k = 0.000
A4 = 1.36963e-05, A6 = -1.93487e-07, A8 = 3.03819e-10
26th page
k = 0.000
A4 = 4.17364e-05, A6 = -3.01793e-07, A8 = 1.61491e-09, A10 = -1.53276e-11, A12 = 5.82244e-14

Zoom data Zoom ratio 1.92
Wide angle Medium telephoto f 7.14 9.88 13.70
FNO. 2.88 2.88 2.88
2ω 114.71 96.68 77.79
IH 10.16 10.73 11.15
FB (in air) 14.74 14.74 14.74
Total length (in air) 112.88 101.60 96.54

d9 28.14 12.76 2.00
d11 6.89 6.46 5.98
d22 1.00 2.36 3.94
d24 1.66 4.79 9.38

When focusing on short-range objects
Wide angle Medium telephoto
d9 29.72 14.35 3.86
d11 5.31 4.86 4.12
d22 1.00 2.36 3.94
d24 1.66 4.79 9.38

Each group focal length
f1 = -15.87 f2 = 60.11 f3 = 16.65 f4 = -18.17 f5 = 35.47

Numerical example 2
Unit mm

Surface data Surface number rd nd νd
Object ∞ ∞
1 39.821 1.75 1.81600 46.62
2 23.000 11.06
3 * 24.731 2.00 1.49700 81.54
4 * 8.505 8.88
5 65.085 1.40 1.49700 81.54
6 * 22.582 7.72
7 -43.136 1.15 1.91082 35.25
8 66.088 2.39
9 57.694 3.04 2.00069 25.46
10 -107.399 variable
11 25.107 0.50 1.92286 18.90
12 11.990 3.53 1.78472 25.68
13 -194.983 Variable
14 (Aperture) ∞ 0.75
15 29.226 1.85 1.43875 94.93
16 -43.198 Variable
17 229.273 4.10 1.49700 81.54
18 -14.418 0.38
19 -13.567 0.50 1.81600 46.62
20 29.367 Variable
21 35.890 1.16 1.88300 40.76
22 33.343 0.10
23 13.255 0.65 1.74000 28.30
24 9.293 3.49 1.43875 94.93
25 342.739 1.26
26 21.049 3.27 1.75520 27.51
27 -20.772 Variable
28 -27.320 0.50 1.85026 32.27
29 10.500 4.00 1.55332 71.68
30 * -29.453 Variable image plane ∞

Aspheric data 3rd surface
k = 0.000
A4 = 8.40972e-06, A6 = -1.96312e-07, A8 = 6.33572e-10, A10 = -6.59131e-13
4th page
k = -0.781
A4 = 2.71176e-06, A6 = 1.07377e-07, A8 = -1.03654e-08, A10 = 4.69259e-11, A12 = -6.74201e-14
6th page
k = -19.553
A4 = 2.45719e-04, A6 = -2.71891e-06, A8 = 4.36132e-08, A10 = -3.26819e-10, A12 = 1.23213e-12
30th page
k = 7.364
A4 = 1.38265e-04, A6 = 8.12349e-08, A8 = 1.19526e-08, A10 = -6.26300e-11

Zoom data zoom 1.92
Wide-angle middle telephoto f 6.12 8.85 11.76
FNO. 2.88 2.88 2.88
2ω 122.21 103.51 85.45
IH 10.15 11.15 11.15
FB (in air) 14.39 19.24 23.78
Total length (in air) 112.45 100.95 97.08

d10 21.86 7.90 1.00
d13 4.80 4.68 2.50
d16 1.50 1.73 3.00
d20 4.25 1.50 0.90
d27 0.23 0.47 0.46
d30 14.39 19.24 23.78

When focusing on short-range objects
Wide angle Medium telephoto
d10 23.03 8.62 1.68
d13 3.63 3.96 1.82
d16 1.50 1.73 3.00
d20 4.25 1.50 0.90
d27 0.23 0.47 0.46
d30 14.39 19.24 23.78

Each group focal length
f1 = -11.41 f2 = 34.33 f3 = 40.04 f4 = -20.03 f5 = 12.29 f6 = -26.45

Numerical Example 3
Unit mm

Surface data Surface number rd nd νd
Object ∞ ∞
1 38.750 2.70 1.72916 54.68
2 20.150 4.10
3 * 17.017 3.00 1.80610 40.88
4 * 8.773 11.01
5 -88.459 1.15 1.43700 95.10
6 17.864 3.68
7 25.150 2.50 1.90366 31.32
8 44.634 Variable
9 * 33.761 3.79 1.59201 67.02
10 * -326.845 variable
11 (Aperture) ∞ Variable
12 -35.000 0.70 2.00069 25.46
13 963.652 0.65
14 65.292 2.46 1.84666 23.78
15 -25.858 variable
16 -34.852 0.70 1.91082 35.25
17 765.081 Variable
18 * 15.416 3.35 1.49700 81.61
19 * -769.308 0.15
20 23.354 1.83 1.80400 46.58
21 10.306 4.31 1.43700 95.10
22 39.932 0.53
23 16.986 6.10 1.43700 95.10
24 -18.122 0.15
25 -91.369 0.85 1.76200 40.10
26 22.184 3.97 1.43700 95.10
27 -24.379 2.41 1.69350 53.18
28 * -73.437 Variable image plane ∞

Aspheric data 3rd surface
k = -0.772
A4 = -3.92747e-05, A6 = 1.50395e-08, A8 = 1.18115e-10, A10 = -1.96180e-13, A12 = -2.59650e-17
4th page
k = -0.994
A4 = -1.02952e-05, A6 = -1.74449e-07, A8 = 2.73995e-10, A10 = 4.31904e-12, A12 = -1.74697e-14
9th page
k = 0.000
A4 = 6.46420e-05, A6 = 1.96489e-07, A8 = 2.99230e-09, A10 = 2.07686e-11
10th page
k = 0.000
A4 = 7.93076e-05, A6 = 1.81734e-07, A8 = 5.20927e-09, A10 = 3.46579e-11
18th page
k = 0.000
A4 = -4.14573e-07, A6 = 2.65414e-07, A8 = -4.10155e-09, A10 = 5.55192e-11
19th page
k = 0.000
A4 = 4.66839e-05, A6 = 4.51038e-07, A8 = -6.38088e-09, A10 = 7.65812e-11
28th page
k = 0.000
A4 = 8.52243e-05, A6 = 4.42744e-07, A8 = -2.52365e-09, A10 = 4.41834e-11, A12 = -1.38054e-13

Zoom data Zoom ratio 1.92
Wide angle Medium telephoto f 7.14 9.90 13.72
FNO. 2.84 2.81 2.88
2ω 112.03 98.51 77.81
IH 9.70 11.15 11.15
FB (in air) 14.64 19.15 24.73
Total length (in air) 111.73 101.03 96.52

d8 16.46 6.79 1.60
d10 7.05 6.03 6.70
d11 5.15 4.20 1.30
d15 0.50 0.76 1.60
d17 7.84 3.96 0.50
d28 14.64 19.15 24.73

When focusing on short-range objects
Wide angle Medium telephoto
d8 17.62 7.98 2.88
d10 5.89 4.84 5.43
d11 5.15 4.20 1.30
d15 0.50 0.76 1.60
d17 7.84 3.96 0.50
d28 14.64 19.15 24.73

Each group focal length
f1 = -13.37 f2 = 51.89 f3 = 55.20 f4 = -36.58 f5 = 22.17

Numerical Example 4
Unit mm

Surface data Surface number rd nd νd
Object ∞ ∞
1 40.857 2.70 1.88300 40.80
2 24.161 4.85
3 29.020 2.50 1.88300 40.80
4 19.322 2.97
5 * 22.072 2.50 1.80610 40.88
6 * 12.388 12.51
7 -50.251 1.70 1.43700 95.10
8 33.573 0.42
9 30.981 4.00 1.90366 31.32
10 90.155 Variable
11 * 16.598 4.00 1.80610 40.88
12 * 22.336 Variable
13 (Aperture) ∞ 1.25
14 41.481 0.70 1.51633 64.14
15 31.481 2.58 1.49700 81.61
16 -27.003 2.61
17 -14.574 0.80 1.53996 59.46
18 12.504 3.11 1.49700 81.61
19 1684.817 0.15
20 * 26.235 3.41 1.49700 81.61
21 * -23.920 0.15
22 -171.223 3.00 1.43700 95.10
23 -17.233 Variable
24 33.531 2.09 1.56883 56.36
25 -172.910 0.80 1.90366 31.32
26 16.111 Variable
27 * 21.000 4.00 1.51633 64.06
28 * -119.058 14.59
Image plane ∞

Aspheric data 5th surface
k = 0.000
A4 = 5.07542e-05, A6 = -3.26124e-07, A8 = 7.23527e-10, A10 = -5.64831e-13
6th page
k = -0.545
A4 = 5.47849e-05, A6 = -3.95024e-07, A8 = -1.11242e-09, A10 = 1.04300e-11, A12 = -2.12350e-14
11th page
k = 0.000
A4 = 2.79972e-05, A6 = 1.18399e-07, A8 = 2.94567e-09, A10 = -8.36669e-12
12th page
k = 0.000
A4 = 6.23392e-05, A6 = 3.91477e-07, A8 = 4.86816e-09, A10 = -1.84851e-11
20th page
k = 0.000
A4 = -3.06299e-05, A6 = 2.92993e-07, A8 = -2.53560e-09, A10 = 3.68190e-11
21st page
k = 0.000
A4 = 4.70106e-05, A6 = 1.86947e-07, A8 = -1.29414e-09, A10 = 3.34999e-11
No. 27
k = 0.000
A4 = 5.08450e-06, A6 = -9.63084e-08, A8 = 4.37614e-10
28th page
k = 0.000
A4 = 2.32475e-05, A6 = -2.19104e-07, A8 = 1.79764e-09, A10 = -1.41583e-11, A12 = 5.51140e-14

Zoom data Zoom ratio 1.91
Wide angle Medium telephoto f 7.20 9.91 13.73
FNO. 2.88 2.88 2.88
2ω 116.82 99.54 82.26
IH 10.19 10.62 11.15
FB (in air) 14.59 14.59 14.59
Total length (in air) 116.21 105.48 100.62

d10 28.04 13.85 2.18
d12 7.98 6.63 7.50
d23 1.00 3.16 6.48
d26 1.81 4.43 7.06

When focusing on short-range objects
Wide angle Medium telephoto
d10 29.61 15.46 4.07
d12 6.41 5.02 5.61
d23 1.00 3.16 6.48
d26 1.81 4.43 7.06

Each group focal length
f1 = -15.86 f2 = 61.13 f3 = 20.96 f4 = -25.38 f5 = 34.91

Numerical Example 5
Unit mm

Surface data Surface number rd nd νd
Object ∞ ∞
1 40.000 2.50 1.88300 40.80
2 22.530 4.89
3 27.243 2.50 1.88300 40.80
4 18.157 2.79
5 * 20.564 2.50 1.80610 40.88
6 * 11.636 11.44
7 -73.513 1.75 1.49700 81.54
8 24.987 4.20 1.90366 31.32
9 98.362 Variable
10 * 16.348 3.72 1.80610 40.88
11 * 21.877 variable
12 (Aperture) ∞ 1.25
13 37.981 0.95 1.72000 46.02
14 26.359 3.22 1.49700 81.54
15 -15.490 1.44
16 -10.950 0.80 1.51633 64.14
17 12.238 2.98 1.49700 81.54
18 170.879 0.15
19 20.681 4.25 1.43700 95.10
20 -17.740 0.15
21 * 112.166 2.85 1.49700 81.61
22 * -18.752 variable
23 -137.026 0.80 1.90366 31.32
24 19.525 Variable
25 * 39.261 4.13 1.51633 64.06
26 * -34.524 Variable image plane ∞

Aspheric data 5th surface
k = 0.000
A4 = 6.57195e-05, A6 = -5.09445e-07, A8 = 1.47888e-09, A10 = -1.69855e-12
6th page
k = -0.500
A4 = 7.32025e-05, A6 = -7.37876e-07, A8 = -3.81674e-10, A10 = 1.47076e-11, A12 = -4.50516e-14
10th page
k = 0.000
A4 = 4.79125e-05, A6 = 4.73335e-08, A8 = 7.67036e-09, A10 = -5.60898e-11
11th page
k = 5.585
A4 = 2.36048e-05, A6 = -3.84290e-07, A8 = 1.77462e-08, A10 = -3.54139e-10
21st page
k = 0.000
A4 = -8.24382e-05, A6 = -6.06057e-07, A8 = 4.46043e-09, A10 = 3.33433e-11
22nd page
k = 0.000
A4 = 1.56244e-05, A6 = -5.11423e-07, A8 = 7.02354e-09, A10 = 2.24911e-11
25th page
k = 0.000
A4 = 4.75833e-06, A6 = -2.33909e-07, A8 = 8.62893e-10
26th page
k = 0.000
A4 = 2.88478e-05, A6 = -2.44406e-07, A8 = 7.64290e-10, A10 = -5.65104e-12, A12 = 3.44034e-14

Zoom data Zoom ratio 2.04
Wide angle Medium telephoto f 6.95 9.88 14.14
FNO. 2.88 2.88 2.88
2ω 116.14 99.21 75.99
IH 10.12 11.15 11.15
FB (in air) 15.52 15.84 16.64
Total length (in air) 113.21 101.40 96.63

d9 29.00 12.75 1.00
d11 6.80 6.40 6.46
d22 1.00 2.37 4.04
d24 1.64 4.78 9.23
d26 15.52 15.84 16.64

When focusing on short-range objects
Wide angle Medium telephoto
d9 30.36 14.20 2.75
d11 5.44 4.95 4.71
d22 1.00 2.37 4.04
d24 1.64 4.78 9.23
d26 15.52 15.84 16.64

Each group focal length
f1 = -15.66 f2 = 61.74 f3 = 16.57 f4 = -18.87 f5 = 36.27

Numerical Example 6
Unit mm

Surface data Surface number rd nd νd
Object ∞ ∞
1 39.821 1.750 1.81600 46.62
2 23.000 11.062
3 * 24.731 2.000 1.49700 81.54
4 * 8.505 8.879
5 65.085 1.400 1.49700 81.54
6 * 22.582 7.715
7 -43.136 1.150 1.91082 35.25
8 66.088 2.392
9 57.694 3.036 2.00069 25.46
10 -107.399 variable
11 25.107 0.500 1.92286 18.90
12 11.990 3.529 1.78472 25.68
13 -194.983 Variable
14 (Aperture) ∞ 0.750
15 29.226 1.855 1.43875 94.93
16 -43.198 Variable
17 229.273 4.102 1.49700 81.54
18 -14.418 0.384
19 -13.567 0.500 1.81600 46.62
20 29.367 Variable
21 35.890 1.158 1.88300 40.76
22 33.343 0.100
23 13.255 0.650 1.74000 28.30
24 9.293 3.495 1.43875 94.93
25 342.739 1.258
26 21.049 3.265 1.75520 27.51
27 -20.772 Variable
28 -27.320 0.500 1.85026 32.27
29 10.500 4.002 1.55332 71.68
30 * -29.453 Variable image plane ∞

Aspheric data 3rd surface
k = 0.0000
A4 = 8.4097e-006, A6 = -1.9631e-007, A8 = 6.3357e-010, A10 = -6.5913e-013
4th page
k = -0.7811
A4 = 2.7118e-006, A6 = 1.0738e-007, A8 = -1.0365e-008, A10 = 4.6926e-011, A12 = -6.7420e-014
6th page
k = -19.5525
A4 = 2.4572e-004, A6 = -2.7189e-006, A8 = 4.3613e-008, A10 = -3.2682e-010, A12 = 1.2321e-012
30th
k = 7.3642
A4 = 1.3827e-004, A6 = 8.1235e-008, A8 = 1.1953e-008, A10 = -6.2630e-011

Zoom data Zoom ratio 1.92
Wide angle Medium telephoto f 6.120 8.850 11.760
FNO. 2.880 2.878 2.880
2ω 121.1 103.5 85.4
IH 10.04 11.15 11.15
FB (in air) 14.388 19.237 23.780
Total length (in air) 112.45452 100.95076 97.07926

d10 21.855 7.899 1.000
d13 4.801 4.681 2.500
d14 0.750 0.750 0.750
d16 1.500 1.731 3.000
d20 4.249 1.500 0.900
d27 0.228 0.469 0.465
d30 14.388 19.237 23.780

When focusing on short-range objects
Wide angle Medium telephoto object distance 160.76909 165.41606 300.00000
d10 21.85549 7.89946 1.00000
d13 4.80055 4.68083 2.50000
d14 0.52468 0.25830 0.22417
d16 1.72532 2.22229 3.52583
d20 4.24879 1.50000 0.90000
d27 0.22826 0.46885 0.46492

Each group focal length
f1 = -11.41193 f2 = 34.32751 f3 = 40.04388 f4 = -20.03396 f5 = 12.28707
f6 = -26.44901
f _Rw = 25.8682

In the above embodiments, the front group has a plurality of lens groups, and the distance between the plurality of lens groups in the front group may change during zooming from the wide-angle end to the telephoto end.
For example, in the numerical data in the sixth embodiment of the present application, even the numerical data of the following modified example has the same effects as the above-described embodiments.

Unit mm

Surface data Surface number rd nd νd
Object ∞ ∞
1 39.821 1.750 1.81600 46.62
2 23.000 11.062
3 * 24.731 2.000 1.49700 81.54
4 * 8.505 8.879
5 65.085 1.400 1.49700 81.54
6 * 22.582 7.715
7 -43.136 1.150 1.91082 35.25
8 66.088 Variable
9 57.694 3.036 2.00069 25.46
10 -107.399 variable
11 25.107 0.500 1.92286 18.90
12 11.990 3.529 1.78472 25.68
13 -194.983 Variable
14 (Aperture) ∞ 0.750
15 29.226 1.855 1.43875 94.93
16 -43.198 Variable
17 229.273 4.102 1.49700 81.54
18 -14.418 0.384
19 -13.567 0.500 1.81600 46.62
20 29.367 Variable
21 35.890 1.158 1.88300 40.76
22 33.343 0.100
23 13.255 0.650 1.74000 28.30
24 9.293 3.495 1.43875 94.93
25 342.739 1.258
26 21.049 3.265 1.75520 27.51
27 -20.772 Variable
28 -27.320 0.500 1.85026 32.27
29 10.500 4.002 1.55332 71.68
30 * -29.453 Variable image plane ∞

Aspheric data 3rd surface
k = 0.0000
A4 = 8.4097e-006, A6 = -1.9631e-007, A8 = 6.3357e-010, A10 = -6.5913e-013
4th page
k = -0.7811
A4 = 2.7118e-006, A6 = 1.0738e-007, A8 = -1.0365e-008, A10 = 4.6926e-011, A12 = -6.7420e-014
6th page
k = -19.5525
A4 = 2.4572e-004, A6 = -2.7189e-006, A8 = 4.3613e-008, A10 = -3.2682e-010, A12 = 1.2321e-012
30th page
k = 7.3642
A4 = 1.3827e-004, A6 = 8.1235e-008, A8 = 1.1953e-008, A10 = -6.2630e-011

Zoom data Zoom ratio 1.92
Wide angle Medium telephoto f 6.122 8.878 11.760
f _F -11.3007 -11.3560 -11.41193
FNO. 2.887 2.887 2.880
2ω 121.1 103.3 85.4
IH 10.04 11.15 11.15
FB (in air) 14.529 19.386 23.780
Total length (in air) 112.59619 100.09960 97.07926

d8 2.192 2.292 2.392
d10 22.055 7.999 1.000
d13 4.801 4.681 2.500
d14 0.750 0.750 0.750
d16 1.500 1.731 3.000
d20 4.249 1.500 0.900
d27 0.228 0.469 0.465
d30 14.529 19.386 23.780

When focusing on short-range objects
Wide angle Medium telephoto object distance 160.76909 165.41606 300.00000
d8 2.192 2.292 2.392
d10 22.055 7.999 1.00000
d13 4.801 4.681 2.50000
d14 0.52468 0.25830 0.22417
d16 1.72532 2.22229 3.52583
d20 4.24879 1.50000 0.90000
d27 0.22826 0.46885 0.46492

Each group focal length
f1 = -6.13 f2 = 37.85 f3 = 34.32751 f4 = 40.04388 f5 = -20.03396
f6 = 12.28707 f7 = -26.44901
f _Rw = 25.8682

  In the above embodiments, the fifth lens is disposed between the second lens group and the third lens group, the third lens group and the fourth lens group, the fourth lens group and the fifth lens group, and the fifth lens group. One or more lens groups may be disposed between at least one of the groups and the sixth lens group.

  Aberration diagrams of Examples 1 to 6 are shown in FIGS. There are two aberration diagrams for one embodiment, which are shown in the order of an aberration diagram when focusing on an object at infinity and an aberration diagram when focusing on a short distance object. In each figure, “FIY” indicates the maximum image height.

  In these aberration diagrams, (a), (b), (c), and (d) indicate spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (at the wide-angle end), respectively. CC).

  Further, (e), (f), (g), and (h) are respectively spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (CC) in the intermediate focal length state 2. ).

  Further, (i), (j), (k), and (l) respectively indicate spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (CC) at the telephoto end. .

Next, the values of conditional expressions (1-3) to (15-1) in the respective examples will be listed. Regarding conditional expression (12), the value at the wide-angle end is listed in the upper row, and the value at the telephoto end is listed in the lower row.
Example 1 Example 2 Example 3 Example 4
(1-3) νd _Fnmax 95.1 81.54 95.1 95.1
(2) FB _w / f _F -0.93 -1.26 -1.10 -0.92
(3-3) f _w × Fno _wmin / f _F -1.30 -1.54 -1.52 -1.31
(4) f _Rw / FB _w 1.70 1.80 1.80 1.70
(5) | r _F1i / f _F | 1.44 2.02 1.51 1.52
(6) θgF _Fn 0.5334 0.5375 0.5334 0.5334
(7) θgF _Fn +0.0016 0.0441 0.0265 0.0441 0.0441
× νd-0.6415
(8) FB _w / LTL _w 0.13 0.13 0.13 0.13
(9-1) SP _F1 3.44 3.73 3.17 3.89
(10) ASP _R θ 50.0 56.7 51 52.30
(11) DTL _w -8.86 -7.43 -8.42 -10.31
(12) | MG _fob ² × (MG _fo ² -1) | 0.20 0.18 0.28 0.20
0.55 1.06 0.87 0.55
(13) f _F / (f _w × f _t ) ^1/2 -1.60 -1.35 -1.35 -1.59
(14) SP _F2 5.06 2.05 3.13 4.98
(15-1) SP _F4 3.49 2.06 0.66 3.56

Example 5 Example 6
(1-3) νd _Fnmax 81.54 81.54
(2) FB _w / f _F -0.99 -1.26
(3-3) f _w × Fno _wmin / f _F -1.28 -1.54
(4) f _Rw / FB _w 1.58 1.80
(5) | r _F1i / f _F | 1.44 2.02
(6) θgF _Fn 0.5375 0.5375
(7) θgF _Fn +0.0016 0.0265 0.026464
× νd-0.6415
(8) FB _w / LTL _w 0.14 0.13
(9-1) SP _F1 3.58 3.73
(10) ASP _R θ 51.00 56.7
(11) DTL _w -9.26 7.35
(12) | MG _fob ² × (MG _fo ² -1) | 0.20 0.18
0.57 1.06
(13) f _F / (f _w × f _t ) ^1/2 -1.58 -1.35
(14) SP _F2 5.00 2.05
(15-1) SP _F4 3.61 2.06

  FIG. 19 is a cross-sectional view of a single lens mirrorless camera as an electronic imaging apparatus. In FIG. 19, a photographing optical system 2 is arranged in a lens barrel of the single lens mirrorless camera 1. The mount unit 3 allows the taking lens system 2 to be attached to and detached from the body of the single lens mirrorless camera 1. As the mount unit 3, a screw type mount, a bayonet type mount, or the like is used. In this example, a bayonet type mount is used. An imaging element surface 4 and a back monitor 5 are disposed on the body of the single lens mirrorless camera 1. A small CCD or CMOS is used as the image sensor.

  As the photographing optical system 2 of the single-lens mirrorless camera 1, for example, the zoom lens shown in the first to sixth embodiments is used.

  20 and 21 are conceptual diagrams of the configuration of the imaging apparatus having the zoom lens shown in Examples 1-6. FIG. 20 is a front perspective view showing the appearance of a digital camera 40 as an imaging apparatus, and FIG. 21 is a rear perspective view of the same. The zoom lens of this embodiment is used for the photographing optical system 41 of the digital camera 40.

  The digital camera 40 of this embodiment includes a photographing optical system 41 positioned on the photographing optical path 42, a shutter button 45, a liquid crystal display monitor 47, and the like. When the shutter button 45 disposed on the upper part of the digital camera 40 is pressed, In conjunction with this, photographing is performed through the photographing optical system 41, for example, the zoom lens of the first embodiment. An object image formed by the photographing optical system 41 is formed on an image sensor (photoelectric conversion surface) provided in the vicinity of the imaging surface. The object image received by the image sensor is displayed on the liquid crystal display monitor 47 provided on the back of the camera as an electronic image by the processing means. In addition, the photographed electronic image can be recorded in a recording unit.

  FIG. 22 is a block diagram showing an internal circuit of a main part of the digital camera 40. In the following description, the processing means described above is configured by, for example, the CDS / ADC unit 24, the temporary storage memory 17, the image processing unit 18, and the like, and the storage unit is configured by the storage medium unit 19 or the like.

  As shown in FIG. 22, the digital camera 40 is connected to the operation unit 12, the control unit 13 connected to the operation unit 12, and the control signal output port of the control unit 13 via buses 14 and 15. An imaging drive circuit 16, a temporary storage memory 17, an image processing unit 18, a storage medium unit 19, a display unit 20, and a setting information storage memory unit 21 are provided.

  The temporary storage memory 17, the image processing unit 18, the storage medium unit 19, the display unit 20, and the setting information storage memory unit 21 can mutually input and output data via the bus 22. In addition, a CCD 49 and a CDS / ADC unit 24 are connected to the imaging drive circuit 16.

  The operation unit 12 includes various input buttons and switches, and notifies the control unit 13 of event information input from the outside (camera user) via these buttons. The control unit 13 is a central processing unit composed of, for example, a CPU, and has a built-in program memory (not shown) and controls the entire digital camera 40 according to a program stored in the program memory.

  The CCD 49 is an image pickup device that is driven and controlled by the image pickup drive circuit 16, converts the light amount of each pixel of the object image formed via the image pickup optical system 41 into an electric signal, and outputs the electric signal to the CDS / ADC unit 24.

  The CDS / ADC unit 24 amplifies the electrical signal input from the CCD 49 and performs analog / digital conversion, and raw video data (Bayer data, hereinafter referred to as RAW data) obtained by performing the amplification and digital conversion. Is output to the temporary storage memory 17.

  The temporary storage memory 17 is a buffer made of, for example, SDRAM, and is a memory device that temporarily stores RAW data output from the CDS / ADC unit 24. The image processing unit 18 reads out the RAW data stored in the temporary storage memory 17 or the RAW data stored in the storage medium unit 19, and includes distortion correction based on the image quality parameter designated by the control unit 13. It is a circuit that performs various image processing electrically.

  The storage medium unit 19 is detachably mounted with a card-type or stick-type recording medium made of, for example, a flash memory, and the RAW data transferred from the temporary storage memory 17 or the image processing unit 18 to these flash memories. Image-processed image data is recorded and held.

  The display unit 20 includes a liquid crystal display monitor 47 and the like, and displays captured RAW data, image data, an operation menu, and the like. The setting information storage memory unit 21 includes a ROM unit that stores various image quality parameters in advance, and a RAM unit that stores image quality parameters read from the ROM unit by an input operation of the operation unit 12.

  The digital camera 40 configured in this manner employs the zoom lens according to the present embodiment as the photographing optical system 41, so that a high resolution image can be obtained without degrading the image quality while having a super wide angle of view and a small size. An imaging device that is advantageous to obtain can be obtained.

  As described above, the present invention provides a zoom lens in which the optical system is sufficiently reduced in size and weight, and has a sufficiently wide angle of view compared to the F-number, and various aberrations are sufficiently reduced. It is suitable for an imaging device having

GF Front group FR Rear group Gfo Focus lens group G1 First lens group G2 Second lens group G3 Third lens group G4 Fourth lens group G5 Fifth lens group G6 Sixth lens group LU1 First lens unit LU2 Second lens unit DESCRIPTION OF SYMBOLS S Aperture stop I Image surface 1 Single-lens mirrorless camera 2 Shooting lens system 3 Lens mount unit 4 Image sensor surface 5 Back monitor 12 Operation unit 13 Control units 14 and 15 Bus 16 Imaging drive circuit 17 Temporary memory 18 Image processing unit DESCRIPTION OF SYMBOLS 19 Storage medium part 20 Display part 21 Setting information storage memory part 22 Bus 24 CDS / ADC part 40 Digital camera 41 Shooting optical system 42 Shooting optical path 45 Shutter button 47 Liquid crystal display monitor 49 CCD

Claims (35)

From the object side to the image side,
A front group having negative refractive power;
A rear group including an aperture stop and having a positive refractive power,
The front group includes a first lens having a negative refractive power and a third lens having a positive refractive power;
The first lens is disposed closest to the object side, and the shape thereof is a meniscus shape having a convex surface facing the object side,
The front group consists of a first lens group,
During zooming from the wide-angle end to the telephoto end, the first lens group moves as a unit,
The rear group is in order from the object side to the image side,
A second lens group having a positive refractive power and positioned closer to the object side than the aperture stop;
A third lens group;
A fourth lens group having negative refractive power;
A fifth lens group having a positive refractive power,
The second lens group or the third lens group has a focus lens group,
When zooming from the wide-angle end to the telephoto end,
The interval between each lens group changes, and
The interval between the front group and the rear group becomes narrower,
A zoom lens satisfying the following conditional expression:
1.65 <SP _F1 <9.0
here,
SP _F1 = (r _F1o + r _F1i ) / (r _F1o -r _F1i )
r _F1o is the paraxial radius of curvature of the object side surface of the first lens,
r _F1i is the paraxial radius of curvature of the image side surface of the first lens,
It is. From the object side to the image side,
A front group having negative refractive power;
A rear group including an aperture stop and having a positive refractive power,
The front group includes a first lens having a negative refractive power and a third lens having a positive refractive power;
The first lens is disposed closest to the object side, and the shape thereof is a meniscus shape having a convex surface facing the object side,
The front group consists of a first lens group,
During zooming from the wide-angle end to the telephoto end, the first lens group moves as a unit,
The rear group is in order from the object side to the image side,
A second lens group having a positive refractive power and positioned closer to the object side than the aperture stop;
A third lens group;
A fourth lens group having negative refractive power;
A fifth lens group having a positive refractive power,
The rear group includes the second lens group, the third lens group, the fourth lens group, and the fifth lens group, or
The rear group includes the second lens group, the third lens group, the fourth lens group, the fifth lens group, and a sixth lens group,
The second lens group or the third lens group has a focus lens group,
When zooming from the wide-angle end to the telephoto end,
The interval between each lens group changes, and
The interval between the front group and the rear group becomes narrower,
A zoom lens satisfying the following conditional expression:
−1.45 <FB _w / f _F <−0.3
here,
FB _w is the back focus at the wide-angle end,
f _F is the focal length of the front group,
It is. From the object side to the image side,
A front group having negative refractive power;
A rear group including an aperture stop and having a positive refractive power,
The front group includes a first lens having a negative refractive power and a third lens having a positive refractive power;
The first lens is disposed closest to the object side, and the shape thereof is a meniscus shape having a convex surface facing the object side,
The front group consists of a first lens group,
During zooming from the wide-angle end to the telephoto end, the first lens group moves as a unit,
The rear group is in order from the object side to the image side,
A second lens group having a positive refractive power and positioned closer to the object side than the aperture stop;
A third lens group;
A fourth lens group having negative refractive power;
A fifth lens group having a positive refractive power,
The second lens group or the third lens group has a focus lens group,
When zooming from the wide-angle end to the telephoto end,
The interval between each lens group changes, and
The interval between the front group and the rear group becomes narrower,
A zoom lens satisfying the following conditional expression:
74 <νd _Fnmax <110
here,
νd _Fnmax is the maximum Abbe number among the Abbe numbers of lenses having negative refractive power included in the front group,
It is. From the object side to the image side,
A front group having negative refractive power;
A rear group including an aperture stop and having a positive refractive power,
The front group includes a first lens having a negative refractive power and a third lens having a positive refractive power;
The first lens is disposed closest to the object side, and the shape thereof is a meniscus shape having a convex surface facing the object side,
The front group consists of a first lens group,
During zooming from the wide-angle end to the telephoto end, the first lens group moves as a unit,
The rear group is in order from the object side to the image side,
A second lens group having a positive refractive power and positioned closer to the object side than the aperture stop;
A third lens group;
A fourth lens group having negative refractive power;
A fifth lens group having a positive refractive power,
The second lens group has a focus lens group,
When zooming from the wide-angle end to the telephoto end,
The interval between each lens group changes, and
The interval between the front group and the rear group becomes narrower,
A zoom lens satisfying the following conditional expression:
1.20 <f _Rw / FB _w <5
here,
f _Rw is the focal length of the rear group at the wide-angle end,
FB _w is the back focus at the wide-angle end,
It is. The zoom lens according to any one of claims 1 to 4, wherein the following conditional expression is satisfied.
1.65 <SP _F1 <9.0
here,
SP _F1 = (r _F1o + r _F1i ) / (r _F1o -r _F1i )
r _F1o is the paraxial radius of curvature of the object side surface of the first lens,
r _F1i is the paraxial radius of curvature of the image side surface of the first lens,
It is. The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
−1.45 <FB _w / f _F <−0.3
here,
FB _w is the back focus at the wide-angle end,
f _F is the focal length of the front group,
It is. The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
52 <νd _Fnmax <110
here,
νd _Fnmax is the maximum Abbe number among the Abbe numbers of lenses having negative refractive power included in the front group,
It is. The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
1.2 <f _Rw / FB _w <5
here,
f _Rw is the focal length of the rear group at the wide-angle end,
FB _w is the back focus at the wide-angle end,
It is. The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
−2.7 <f _w × Fno _wmin / f _F <−0.5
here,
f _F is the focal length of the front group,
_fw is the focal length of the entire zoom lens system at the wide-angle end,
Fno _wmin is the smallest F number at the wide-angle end,
It is. The zoom lens according to any one of claims 1 to 9, wherein the following conditional expression is satisfied.
−25 <DTL _w <7
here,
DTL _w is distortion at the maximum angle of view at the wide-angle end, and is expressed by DTL _w = (IH _w1 −IH _w2 ) / IH _w2 × 100 (%),
IH _w1 is the real image height at which the maximum field angle at the wide-angle end from the infinite object point is imaged on the image plane,
IH _w2 is the paraxial image height at which the maximum field angle at the wide-angle end from the infinite object point is imaged on the image plane,
It is. The front group includes a second lens having a negative refractive power. The second lens is disposed closer to the image side than the first lens and has a meniscus shape with a convex surface facing the object side. The zoom lens according to claim 1, wherein the zoom lens is a zoom lens.   The zoom lens according to claim 11, wherein the front group further includes a fourth lens having negative refractive power. The front group further includes a fourth lens having negative refractive power;
The zoom lens according to claim 11, wherein a shape of the fourth lens is a meniscus shape. The front group further includes a fourth lens having negative refractive power;
The zoom lens according to claim 11, wherein the fourth lens has a meniscus shape with a convex surface facing the object side.   The zoom lens according to any one of claims 12 to 14, wherein the fourth lens is disposed on an image side of the second lens. The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
1.1 <| r _F1i / f _F | <3
here,
r _F1i is the paraxial radius of curvature of the image side surface of the first lens,
f _F is the focal length of the front group,
It is. The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
0.53 <θgF _Fn <0.55
here,
θgF _Fn is a partial dispersion ratio in a lens having the largest Abbe number among the lenses having negative refractive power included in the front group, and θgF _Fn = (ng−nF) / (nF−nc) Represented by
ng, nF, and nc are refractive indexes of the g-line, F-line, and C-line of the lens having the largest Abbe number,
It is. The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
0.01 <θgF _Fn + 0.0016 × νd−0.6415 <0.054
here,
θgF _Fn is a partial dispersion ratio in a lens having the largest Abbe number among the lenses having negative refractive power included in the front group, and θgF _Fn = (ng−nF) / (nF−nc) Represented by
ng, nF, and nc are refractive indexes of the g-line, F-line, and C-line of the lens having the largest Abbe number,
νd is the Abbe number of the lens having the largest Abbe number value,
It is. The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
0.06 <FB _w / LTL _w <0.20
here,
FB _w is the back focus at the wide-angle end,
LTL _w is the axial distance from the most object-side surface of the zoom lens to the image plane at the wide-angle end,
It is. The zoom lens according to any one of claims 1 to 19, wherein the following conditional expression is satisfied.
1.6 <SP _F2 <6
here,
SP _F2 = (r _F2o + r _F2i ) / (r _F2o -r _F2i )
r _F2o is the paraxial radius of curvature of the object side surface of the second lens,
r _F2i is the paraxial radius of curvature of the image side surface of the second lens,
It is.   21. The zoom lens according to claim 1, wherein the second lens group includes a focus lens group.   The zoom lens according to any one of claims 1 to 20, wherein the third lens group includes a focus lens group.   The zoom lens according to any one of claims 1 to 22, wherein the front group moves during zooming. The second lens group or the third lens group has a camera shake reduction lens unit,
The zoom lens according to any one of claims 1 to 23, wherein image blur due to camera shake is reduced by moving the camera shake reduction lens unit in a direction perpendicular to the optical axis. The second lens group includes a camera shake reduction lens unit;
25. The zoom lens according to claim 24, wherein image blur due to camera shake is reduced by moving the camera shake reduction lens unit in a direction perpendicular to the optical axis. The second lens group is a camera shake reduction lens unit;
26. The zoom lens according to claim 25, wherein image blur due to camera shake is reduced by moving the camera shake reduction lens unit in a direction perpendicular to the optical axis. The third lens group includes a camera shake reduction lens unit;
25. The zoom lens according to claim 24, wherein image blur due to camera shake is reduced by moving the camera shake reduction lens unit in a direction perpendicular to the optical axis. The third lens group is a camera shake reduction lens unit;
28. The zoom lens according to claim 27, wherein image blur due to camera shake is reduced by moving the camera shake reduction lens unit in a direction perpendicular to the optical axis.   The zoom lens according to any one of claims 1 to 28, wherein the lens group located closest to the image side has a positive refractive power. 2. The lens in the front group, wherein at least one of the meniscus lenses having a convex surface facing the object side has an aspherical surface satisfying the following conditional expression: 30. The zoom lens according to any one of 29.
30 ° <ASP _R θ <70 °
here,
ASP _R θ is the inclination of the surface at a predetermined position of the image side surface of the at least one lens,
The predetermined position is a position where an effective aperture is maximum in the at least one lens,
The inclination of the surface is an angle at which the tangent of the surface at the predetermined position and the optical axis intersect,
It is. Having a predetermined lens group,
The predetermined lens group is a lens group located between an image side surface and an image plane of the focus lens group,
The zoom lens according to any one of claims 1 to 30, wherein the following conditional expression is satisfied.
0.10 <| MG _fob ² × (MG _fo ² −1) | <3.0
here,
MG _fo is the lateral magnification of the focus lens group at an arbitrary position,
MG _fob is a lateral magnification of the predetermined lens group at the same position as the arbitrary position,
It is. The zoom lens according to any one of claims 1 to 31, wherein the following conditional expression is satisfied.
−2.0 <f _F / (f _w × f _t ) ^1/2 <−1.0
f _F is the focal length of the front group,
_fw is the focal length of the entire zoom lens system at the wide-angle end,
f _t is the focal length of the entire zoom lens system at the telephoto end,
It is. The zoom lens according to any one of claims 12 to 15, wherein the following conditional expression is satisfied.
0.3 <SP _F4 <4.5
here,
SP _F4 = (r _F4o + r _F4i ) / (r _F4o -r _F4i )
r _F4o is the paraxial radius of curvature of the object side surface of the fourth lens;
r _F4i is the paraxial radius of curvature of the image side surface of the fourth lens,
It is. The front group consists of a first lens group,
The rear group includes the second lens group, the third lens group, the fourth lens group, and the fifth lens group, or
The rear group includes the second lens group, the third lens group, the fourth lens group, the fifth lens group, and a sixth lens group,
  The zoom lens according to any one of claims 1 to 33, wherein the distance between the lens groups changes upon zooming from the wide-angle end to the telephoto end. A zoom lens according to any one of claims 1 to 34;
An image pickup device having an image pickup surface and converting an image formed on the image pickup surface by the zoom lens into an electric signal.