Zoom lens, optical device, and method of manufacturing zoom lens

Abstract

In a photographic lens, desired is a zoom lens which is compact yet has excellent optical performance with various aberrations corrected from a wide-angle end state to a telephoto end state.　This zoom lens, in order from the object side, is configured of a front group and a rear group. The front group and the rear group are spaced apart by the longest air gap within the optical system in the wide-angle end state. The front group has negative refractive power at least in the wide-angle end state. The rear group has positive refractive power at least in the wide-angle end state, and is configured by a plurality of lens groups whose mutually adjacent air gaps change during magnification. The lens group closest to the object side has positive refractive power. The zoom lens satisfies the following conditional expression. 1.90 < (-fFw) / fw < 4.00, where fFw is the focal length of the front group with respect to the d-line in the wide-angle end state, and fw is the focal length of the zoom lens with respect to the d-line in the wide-angle end state.

Description

Zoom lens, optical device, and method for manufacturing zoom lens

[0001] The present invention relates to a zoom lens, an optical apparatus, and a method for manufacturing a zoom lens.

[0002] Zoom lenses suitable for photo cameras, electronic still cameras, video cameras, etc. have been proposed in the past (see, for example, Japanese Patent Application Laid-Open No. 2003-121199). However, it is difficult to achieve good optical performance while keeping such zoom lenses compact.

[0003] JP 2014-077867 A

[0004] A zoom lens according to a first embodiment comprises, in order from the object side, a front group and a rear group, the front group and the rear group being separated by the longest air gap in the optical system in the wide-angle end state, the front group having negative refractive power at least in the wide-angle end state, the rear group having positive refractive power at least in the wide-angle end state, and comprising a plurality of lens groups whose adjacent air gaps change during magnification, the lens group closest to the object side having positive refractive power, and satisfying the following conditional expression: 1.90 < (-fFw) / fw < 4.00, where fFw: focal length of the front group relative to the d-line in the wide-angle end state fw: focal length of the zoom lens relative to the d-line in the wide-angle end state

[0005] Furthermore, a zoom lens according to a second aspect is a zoom lens which is composed of, in order from the object side, a front group and a rear group, the front group and the rear group being separated by the longest air gap within the optical system in the wide-angle end state, the front group having negative refractive power at least in the wide-angle end state, the rear group having positive refractive power at least in the wide-angle end state, and which is composed of a plurality of lens groups whose air gaps between adjacent lens groups change during magnification, the lens group closest to the object side having positive refractive power, and the rear group having an image stabilizing lens group, and which satisfies the following conditional expression: 10.0 < |fv| / fw < 30.0 0.50 < Lvw / LRw < 0.80 where, fv: focal length of the vibration-reduction lens group at the d-line fw: focal length of the zoom lens at the wide-angle end state at the d-line Lvw: distance from the lens surface of the vibration-reduction lens group closest to the image to the lens surface of the entire system closest to the image in the wide-angle end state LRw: distance from the lens surface of the rear group closest to the object to the lens surface of the entire system closest to the image in the wide-angle end state

[0006] An optical apparatus according to a third aspect includes the zoom lens described above.

[0007] A manufacturing method for a zoom lens according to a fourth aspect comprises, in order from the object side, a front group and a rear group, the front group and the rear group being separated by the longest air gap in the optical system in the wide-angle end state, the front group having negative refractive power at least in the wide-angle end state, the rear group having positive refractive power at least in the wide-angle end state, and comprising a plurality of lens groups whose adjacent air gaps change during magnification, the lens group closest to the object side having positive refractive power, and the zoom lens is configured to satisfy the following conditional expression: 1.90 < (-fFw) / fw < 4.00, where fFw: focal length of the front group relative to the d-line in the wide-angle end state fw: focal length of the zoom lens relative to the d-line in the wide-angle end state

[0008] Furthermore, a manufacturing method for a zoom lens according to a fifth aspect comprises a zoom lens which is composed of, in order from the object side, a front group and a rear group, the front group and the rear group being separated by the longest air gap within the optical system in the wide-angle end state, the front group having negative refractive power at least in the wide-angle end state, the rear group having positive refractive power at least in the wide-angle end state, and which is composed of a plurality of lens groups whose air gaps between adjacent lens groups change during magnification, the lens group closest to the object side having positive refractive power, and the rear group being configured to include an image stabilizing lens group, and which is configured to satisfy the following conditional expression: 10.0 < |fv| / fw < 30.0 0.50 < Lvw / LRw < 0.80 where, fv: focal length of the vibration-reduction lens group at the d-line fw: focal length of the zoom lens at the wide-angle end state at the d-line Lvw: distance from the lens surface of the vibration-reduction lens group closest to the image to the lens surface of the entire system closest to the image in the wide-angle end state LRw: distance from the lens surface of the rear group closest to the object to the lens surface of the entire system closest to the image in the wide-angle end state

[0009] 1 is a cross-sectional view of a zoom lens according to Example 1. FIG. 2 is a diagram illustrating various aberrations of the zoom lens according to Example 1 in a wide-angle end state. FIG. 3 is a diagram illustrating various aberrations of the zoom lens according to Example 1 in a telephoto end state. FIG. 4 is a cross-sectional view of a zoom lens according to Example 2. FIG. 5 is a diagram illustrating various aberrations of the zoom lens according to Example 2 in a wide-angle end state. FIG. 6 is a diagram illustrating various aberrations of the zoom lens according to Example 2 in a telephoto end state. FIG. 7 is a cross-sectional view of a zoom lens according to Example 3. FIG. 8 is a diagram illustrating various aberrations of the zoom lens according to Example 3 in a wide-angle end state. FIG. 9 is a diagram illustrating various aberrations of the zoom lens according to Example 3 in a telephoto end state. FIG. 10 is a cross-sectional view of a zoom lens according to Example 1. FIG. 11 is a diagram illustrating various aberrations of the zoom lens according to Example 1 in a wide-angle end state. FIG. 12 is a diagram illustrating various aberrations of the zoom lens according to Example 1 in a telephoto end state. FIG. 13 is a cross-sectional view of a zoom lens according to Example 1. FIG. 14 is a diagram illustrating various aberrations of the zoom lens according to Example 1 in a wide-angle end state. FIG. 15 is a diagram illustrating various aberrations of the zoom lens according to Example 1 in a telephoto end state. FIG. 16 is a cross-sectional view of a zoom lens according to Example 1. FIG. 17 is a diagram illustrating various aberrations of the zoom lens according to Example 1 in a wide-angle end state. FIG. 10 is a cross-sectional view of a zoom lens according to Example 7. FIG. 11 is a diagram showing various aberrations of the zoom lens according to Example 7 in a wide-angle end state. FIG. 12 is a diagram showing various aberrations of the zoom lens according to Example 7 in a telephoto end state. FIG. 13 is a diagram showing the configuration of an optical device including a zoom lens. FIG. 14 is a flowchart showing an outline of a method for manufacturing a zoom lens according to Example 1. FIG. 15 is a flowchart showing an outline of a method for manufacturing a zoom lens according to Example 2.

[0010] A zoom lens, an optical apparatus, and a method for manufacturing a zoom lens according to a first embodiment of the present invention will be described below. However, the present invention is not limited to the following embodiments, and any combination may be used. Furthermore, to avoid complication of explanation due to an increase in the number of reference symbols, the reference symbols for the figures according to the embodiments may be used independently in each drawing. Therefore, even if reference symbols common to other drawings are used, they do not necessarily represent the same configuration as those in the other drawings.

[0011] First, we will explain the zoom lens according to the first embodiment. The zoom lens ZL according to the first embodiment is composed of, in order from the object side, a front group GF and a rear group GR, the front group GF and the rear group GR being separated by the longest air gap within the optical system in the wide-angle end state, the front group GF having negative refractive power at least in the wide-angle end state, the rear group GR having positive refractive power at least in the wide-angle end state, and composed of a plurality of lens groups whose adjacent air gaps change during magnification, with the lens group closest to the object side having positive refractive power.

[0012] With this configuration, the zoom lens ZL of the first embodiment satisfies the following conditional expression (1): 1.90<(-fFw) / fw<4.00 (1) where fFw is the focal length of the front group at the d line in the wide-angle end state, and fw is the focal length of the zoom lens at the d line in the wide-angle end state.

[0013] The conditional expression (1) defines the ratio between the focal length of the front group at the d-line in the wide-angle end state and the focal length of the zoom lens at the d-line in the wide-angle end state. By satisfying the conditional expression (1), various aberrations, particularly coma and curvature of field at the wide-angle end, and spherical aberration and coma at the telephoto end, can be effectively corrected.

[0014] It should be noted that the effect of the first embodiment can be more reliably achieved by setting the lower limit of conditional expression (1) to 1.91. In order to further ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional expression (1) to 1.92, 1.93, 1.94, 1.95, or even 1.96.

[0015] On the other hand, by setting the upper limit of conditional expression (1) to 3.60, the effect of the first embodiment can be more reliably achieved. Furthermore, in order to further ensure the effect of the first embodiment, it is more preferable to set the upper limit of conditional expression (1) to 3.30, 3.00, 2.80, 2.60, or even 2.40.

[0016] With the above-described configuration, the zoom lens of the first embodiment can realize a zoom lens that is compact yet has good optical performance in which various aberrations, particularly spherical aberration and coma, are well corrected from the wide-angle end state to the telephoto end state.

[0017] In the zoom lens ZL of the first embodiment, it is desirable that the front group GF has three or more negative lenses, at least three of the three or more negative lenses in the front group be arranged in order from the most object side, and that the following condition be satisfied: 0.50 < fg1 / fFw < 2.50 (2), where fg1 is the composite focal length at the d-line of a negative lens that is arranged in front of the second negative lens from the image side among the negative lenses arranged in order from the most object side.

[0018] Conditional expression (2) defines the ratio of the composite focal length, at the d-line, of the negative lenses arranged in order from the object side to the negative lens arranged in front of the second negative lens from the image side, to the focal length, at the d-line, of the front group in the wide-angle end state. By satisfying conditional expression (2), various aberrations, particularly coma and curvature of field at the wide-angle side, and spherical aberration and coma at the telephoto side, can be effectively corrected.

[0019] It should be noted that the effect of the first embodiment can be more reliably achieved by setting the lower limit of conditional expression (2) to 0.55. In order to further ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional expression (2) to 0.60, 0.65, 0.70, 0.75, 0.80, or even 0.83.

[0020] On the other hand, by setting the upper limit of conditional expression (2) to 2.20, the effect of the first embodiment can be more reliably achieved. Furthermore, in order to further ensure the effect of the first embodiment, it is more preferable to set the upper limit of conditional expression (2) to 2.00, 1.80, 1.60, 1.50, 1.40, 1.30, or even 1.25.

[0021] In the zoom lens ZL of the first embodiment, it is desirable that the front group GF has three or more negative lenses, at least three of the three or more negative lenses in the front group be arranged in order from the most object side, and that the following condition be satisfied: 2.50 < fg2 / fFw < 12.00 (3), where fg2 is the focal length at the d-line of the second negative lens from the image side among the negative lenses arranged in order from the most object side.

[0022] Conditional expression (3) defines the ratio of the focal length at the d-line of the second negative lens element from the image side among the negative lenses arranged in order from the object side to the focal length at the d-line of the front lens group in the wide-angle end state. By satisfying conditional expression (3), various aberrations, particularly coma and curvature of field at the wide-angle end, and spherical aberration and coma at the telephoto end, can be effectively corrected.

[0023] It should be noted that the effect of the first embodiment can be more reliably achieved by setting the lower limit of conditional expression (3) to 2.70. In order to further ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional expression (3) to 2.80, 2.90, 3.00, 3.10, 3.20, or even 3.30.

[0024] On the other hand, by setting the upper limit of conditional expression (3) to 11.00, the effect of the first embodiment can be more reliably achieved. Furthermore, in order to further ensure the effect of the first embodiment, it is more preferable to set the upper limit of conditional expression (3) to 10.00, 9.50, 9.00, 8.00, 7.00, 6.00, or even 5.00.

[0025] Furthermore, in the zoom lens ZL of the first embodiment, it is desirable that the rear group GR has a vibration-reduction lens group Gv and satisfy the following conditional expressions: 10.00 < |fv| / fw < 30.00 (4) 0.50 < Lvw / LRw < 0.80 (5) where, fv: focal length of the vibration-reduction lens group with respect to the d-line, Lvw: distance from the lens surface of the vibration-reduction lens group closest to the image to the lens surface of the entire system closest to the image in the wide-angle end state, and LRw: distance from the lens surface of the rear group closest to the object to the lens surface of the entire system closest to the image in the wide-angle end state.

[0026] The vibration-reduction lens group Gv corrects image blur caused by camera shake, etc. by moving a lens group or a partial lens group so that it has a displacement component perpendicular to the optical axis, or by rotating (oscillating) it in a plane including the optical axis. Image blur correction, which moves the image sensor so that it has a displacement component perpendicular to the optical axis, may also be used in combination, but the vibration-reduction lens group method is preferable because it does not cause image distortion during correction.

[0027] Conditional expression (4) defines the focal length of the vibration-reduction lens group relative to the d-line and the focal length of the zoom lens relative to the d-line in the wide-angle end state. Conditional expression (5) defines the distance from the lens surface of the vibration-reduction lens group closest to the image in the wide-angle end state to the lens surface closest to the image in the entire system, and the distance from the lens surface of the rear group closest to the object to the lens surface closest to the image in the entire system in the wide-angle end state. By satisfying conditional expressions (4) and (5), various aberrations, particularly changes in field curvature during vibration reduction at the wide-angle end and decentering coma during vibration reduction at the telephoto end, can be effectively corrected.

[0028] It should be noted that the effect of the first embodiment can be more reliably achieved by setting the lower limit of conditional expression (4) to 11.00. In order to further ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional expression (4) to 12.00, 13.00, 14.00, 14.50, or even 15.00.

[0029] On the other hand, by setting the upper limit of conditional expression (4) to 28.00, the effect of the first embodiment can be more reliably achieved. Also, in order to further ensure the effect of the first embodiment, it is more preferable to set the upper limit of conditional expression (4) to 26.00, 24.00, 22.00, 21.00, 20.60, 20.00, 19.00, or even 18.00.

[0030] It should be noted that the effect of the first embodiment can be more reliably achieved by setting the lower limit of conditional expression (5) to 0.52. In order to further ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional expression (5) to 0.54, more preferably 0.56, 0.57, 0.58, or even 0.59.

[0031] On the other hand, by setting the upper limit of conditional expression (5) to 0.78, the effect of the first embodiment can be more reliably achieved. Furthermore, in order to further ensure the effect of the first embodiment, it is more preferable to set the upper limit of conditional expression (5) to 0.76, 0.74, 0.73, 0.72, 0.71, or even 0.70.

[0032] Furthermore, the zoom lens ZL of the second embodiment is composed of, in order from the object side, a front group GF and a rear group GR, the front group GF and the rear group GR being separated by the longest air gap within the optical system in the wide-angle end state, the front group GF having negative refractive power at least in the wide-angle end state, the rear group GR having positive refractive power at least in the wide-angle end state, and composed of a plurality of lens groups whose adjacent air gaps change during magnification, the lens group closest to the object side having positive refractive power, the rear group GR having an image stabilizing lens group Gv, and satisfying the following conditional expression: 10.00 < |fv| / fw < 30.00 (4) 0.50 < Lvw / LRw < 0.80 (5) where, fv: focal length of the vibration-reduction lens group relative to the d-line, fw: focal length of the zoom lens relative to the d-line in the wide-angle end state, Lvw: distance from the lens surface of the vibration-reduction lens group closest to the image to the lens surface of the entire system closest to the image in the wide-angle end state, and LRw: distance from the lens surface of the rear group closest to the object to the lens surface of the entire system closest to the image in the wide-angle end state.

[0033] The vibration-reduction lens group Gv corrects image blur caused by camera shake or the like by moving a lens group or a partial lens group so that the lens group or partial lens group has a displacement component perpendicular to the optical axis, or by rotating (oscillating) the lens group in a plane including the optical axis. Image blur correction, which moves the imaging element so that the image sensor has a displacement component perpendicular to the optical axis, may also be used, but the vibration-reduction lens group method is preferable because it does not cause image distortion during correction. By satisfying conditional expressions (4) and (5), various aberrations, particularly changes in field curvature during vibration reduction at the wide-angle end and decentering coma during vibration reduction at the telephoto end, can be effectively corrected.

[0034] Furthermore, in the zoom lens ZL of the first or second embodiment, it is desirable that the rear group GR has a vibration-reduction lens group Gv and satisfy the following conditional expressions: 1.50 < |fv| / fvRw < 3.50 (6) 0.50 < Lvw / LRw < 0.80 (5) where, fv: focal length of the vibration-reduction lens group at the d-line, fvRw: composite focal length of the lens on the image side of the vibration-reduction lens group at the wide-angle end state at the d-line, Lvw: distance from the lens surface of the vibration-reduction lens group closest to the image to the lens surface closest to the image in the entire system at the wide-angle end state, LRw: distance from the lens surface of the rear group closest to the object to the lens surface closest to the image in the entire system at the wide-angle end state

[0035] Conditional expression (6) defines the ratio between the focal length of the vibration-reduction lens group at the d-line and the combined focal length of the lens on the image side of the vibration-reduction lens group at the wide-angle end state at the d-line. By satisfying conditional expressions (6) and (5), various aberrations, particularly changes in field curvature during vibration reduction at the wide-angle end and decentering coma during vibration reduction at the telephoto end, can be effectively corrected.

[0036] It should be noted that by setting the lower limit of conditional expression (6) to 1.60, the effects of the first or second embodiment can be more reliably achieved. Furthermore, in order to further ensure the effects of the first or second embodiment, it is more preferable to set the lower limit of conditional expression (6) to 1.70, 1.75, 1.80, 1.85, 1.90, 1.95, 2.00, or even 2.05.

[0037] On the other hand, by setting the upper limit of conditional expression (6) to 3.30, the effect of the first or second embodiment can be more reliably achieved. Furthermore, in order to further ensure the effect of the first or second embodiment, it is more preferable to set the upper limit of conditional expression (6) to 3.10, 3.00, 2.90, 2.80, 2.70, or even 2.60.

[0038] In the zoom lens ZL of the first or second embodiment, it is desirable that the rear group GR has a vibration-reduction lens group Gv and satisfy the following conditional expressions: 3.00 < |fv| / fRw < 8.00 (7) 0.50 < Lvw / LRw < 0.80 (5) where, fv: focal length of the vibration-reduction lens group for the d-line fRw: focal length of the rear group for the d-line in the wide-angle end state Lvw: distance from the lens surface of the vibration-reduction lens group closest to the image in the wide-angle end state to the lens surface of the entire system closest to the image LRw: distance from the lens surface of the rear group closest to the object in the wide-angle end state to the lens surface of the entire system closest to the image

[0039] Conditional expression (7) defines the ratio between the focal length of the vibration-reduction lens group at the d-line and the focal length of the rear group at the wide-angle end state at the d-line. By satisfying conditional expressions (7) and (5), various aberrations, particularly changes in field curvature during vibration reduction at the wide-angle end and decentering coma during vibration reduction at the telephoto end, can be effectively corrected.

[0040] It should be noted that by setting the lower limit of conditional expression (7) to 3.30, the effects of the first or second embodiment can be more reliably achieved. Furthermore, in order to further ensure the effects of the first or second embodiment, it is more preferable to set the lower limit of conditional expression (7) to 3.60, 3.80, 4.00, 4.20, 4.40, 4.50, 4.60, or even 4.70.

[0041] On the other hand, by setting the upper limit of conditional expression (7) to 7.75, the effect of the first or second embodiment can be more reliably achieved. Furthermore, in order to further ensure the effect of the first or second embodiment, it is more preferable to set the upper limit of conditional expression (7) to 7.50, 7.25, 7.00, 6.85, 6.70, or even 6.60.

[0042] Furthermore, in the zoom lens ZL of the first or second embodiment, it is desirable that the rear group GR has a vibration-reduction lens group Gv and satisfy the following conditional expressions: 3.00 < |fv| / ft < 30.00 (8) 0.50 < Lvt / LRt < 0.80 (9) where, fv: focal length of the vibration-reduction lens group for the d-line ft: focal length of the zoom lens for the d-line in the telephoto end state Lvt: distance from the lens surface of the vibration-reduction lens group closest to the image in the telephoto end state to the lens surface closest to the image in the entire system LRt: distance from the lens surface of the rear group closest to the object in the telephoto end state to the lens surface closest to the image in the entire system

[0043] Conditional expression (8) defines the ratio between the focal length of the vibration-reduction lens group at the d-line and the focal length of the zoom lens at the telephoto end state at the d-line. Conditional expression (9) defines the ratio between the distance from the lens surface closest to the image in the vibration-reduction lens group at the telephoto end state to the lens surface closest to the image in the entire system and the distance from the lens surface closest to the object in the rear group to the lens surface closest to the image in the entire system at the telephoto end state. By satisfying conditional expressions (8) and (9), various aberrations, particularly changes in field curvature during vibration reduction at the wide-angle end and decentering coma during vibration reduction at the telephoto end, can be effectively corrected.

[0044] It should be noted that by setting the lower limit of conditional expression (8) to 4.00, the effects of the first or second embodiment can be more reliably achieved. In order to further ensure the effects of the first or second embodiment, it is more preferable to set the lower limit of conditional expression (8) to 5.00, 6.00, 7.00, 7.50, or even 8.00.

[0045] On the other hand, by setting the upper limit of conditional expression (8) to 26.00, the effect of the first or second embodiment can be more reliably achieved. Furthermore, in order to further ensure the effect of the first or second embodiment, it is more preferable to set the upper limit of conditional expression (8) to 23.00, 20.00, 18.00, 16.00, 14.00, 13.00, 12.00, or even 11.00.

[0046] Note that by setting the lower limit of conditional expression (9) to 0.52, the effects of the first or second embodiment can be more reliably achieved. Furthermore, in order to further ensure the effects of the first or second embodiment, it is more preferable to set the lower limit of conditional expression (9) to 0.54, more preferably 0.56, 0.57, 0.58, 0.59, or even 0.60.

[0047] On the other hand, by setting the upper limit of conditional expression (9) to 0.78, the effect of the first or second embodiment can be more reliably achieved. Furthermore, in order to further ensure the effect of the first or second embodiment, it is more preferable to set the upper limit of conditional expression (9) to 0.76, 0.75, 0.74, 0.73, 0.72, 0.71, or even 0.70.

[0048] In the zoom lens ZL of the first or second embodiment, it is desirable that the rear group GR has a vibration-reduction lens group Gv and a focusing lens group Gf, and that the following conditional expression be satisfied: 3.00<-(fv / ff)<10.00 (10), where fv is the focal length of the vibration-reduction lens group relative to the d-line, and ff is the focal length of the focusing lens group relative to the d-line.

[0049] Conditional expression (10) defines the focal length of the vibration-reduction lens group relative to the d-line and the focal length of the focusing lens group relative to the d-line. By satisfying conditional expression (10), various aberrations, particularly changes in field curvature during vibration reduction and decentering coma, can be effectively corrected throughout the entire zoom range.

[0050] Note that by setting the lower limit of conditional expression (10) to 3.40, the effects of the first or second embodiment can be more reliably achieved. In order to further ensure the effects of the first or second embodiment, the lower limit of conditional expression (10) is preferably set to 3.80, and more preferably set to 4.10, 4.40, 4.70, 4.90, 5.10, 5.30, or 5.50.

[0051] On the other hand, by setting the upper limit of conditional expression (10) to 9.50, the effects of the first or second embodiment can be more reliably achieved. Also, in order to more reliably achieve the effects of the first or second embodiment, it is preferable to set the upper limit of conditional expression (10) to 9.00, and it is even more preferable to set it to 8.70, 8.40, 8.10, 7.90, 7.70, or 7.50.

[0052] In the zoom lens ZL of the first or second embodiment, it is desirable that the rear group GR has a vibration reduction lens group Gv and a focusing lens group Gf, and that the following condition be satisfied: 0.20 < Lft / Lvt < 0.90 (11) where Lft is the distance from the lens surface of the focusing lens group closest to the image to the lens surface closest to the image in the entire system when focusing on infinity in the telephoto end state, and Lvt is the distance from the lens surface of the vibration reduction lens group closest to the image to the lens surface closest to the image in the entire system in the telephoto end state.

[0053] In the rear group GR, the vibration-reduction lens group Gv is arranged closer to the object than the focusing lens group Gf, and conditional expression (11) defines the ratio between the distance from the lens surface closest to the image in the focusing lens group when focusing on infinity in the telephoto end state to the lens surface closest to the image in the entire system, and the distance from the lens surface closest to the image in the vibration-reduction lens group to the lens surface closest to the image in the entire system in the telephoto end state. By satisfying conditional expression (11), various aberrations, particularly changes in field curvature during vibration reduction and decentering coma aberration, can be effectively corrected throughout the entire zoom range.

[0054] Note that by setting the lower limit of conditional expression (11) to 0.23, the effects of the first or second embodiment can be more reliably achieved. In order to further ensure the effects of the first or second embodiment, the lower limit of conditional expression (11) is preferably set to 0.26, and more preferably set to 0.28, 0.30, 0.32, 0.33, 0.34, 0.35, or even 0.36.

[0055] On the other hand, by setting the upper limit of conditional expression (11) to 0.85, the effect of the first or second embodiment can be more reliably achieved. Also, in order to more reliably achieve the effect of the first or second embodiment, the upper limit of conditional expression (11) is preferably set to 0.80, and more preferably set to 0.75, 0.70, 0.67, 0.64, or even 0.62.

[0056] It is also desirable that the zoom lens ZL of the first or second embodiment satisfy the following condition: 0.20<(-fFw) / fR1<1.50 (12) where fFw is the focal length of the front group relative to the d-line in the wide-angle end state, and fR1 is the focal length of the lens group closest to the object side in the rear group relative to the d-line.

[0057] Conditional expression (12) defines the ratio of the focal length of the front group at the d-line to the focal length of the rear group that is closest to the object at the d-line in the wide-angle end state. By satisfying conditional expression (12), various aberrations, particularly coma and curvature of field at the wide-angle end, and spherical aberration and coma at the telephoto end, can be effectively corrected.

[0058] Note that by setting the lower limit of conditional expression (12) to 0.23, the effects of the first or second embodiment can be more reliably achieved. In order to further ensure the effects of the first or second embodiment, the lower limit of conditional expression (12) is preferably set to 0.26, and more preferably set to 0.28, 0.30, 0.31, 0.32, 0.33, or even 0.34.

[0059] On the other hand, by setting the upper limit of conditional expression (12) to 1.30, the effects of the first or second embodiment can be more reliably achieved. Also, in order to more reliably achieve the effects of the first or second embodiment, it is preferable to set the upper limit of conditional expression (12) to 1.20, and more preferably to 1.10, 1.00, 0.98, 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, or even 0.60.

[0060] In the zoom lens ZL of the first or second embodiment, it is desirable that the rear group GR has a vibration-reduction lens group Gv and satisfy the following condition: 0.080<(-fFw) / |fv|<0.50 (13) where, fFw: focal length of the front group with respect to the d-line in the wide-angle end state, fv: focal length of the vibration-reduction lens group with respect to the d-line.

[0061] Conditional expression (13) defines the ratio between the focal length of the front lens group at the d-line and the focal length of the vibration-reduction lens group at the d-line in the wide-angle end state. By satisfying conditional expression (13), various aberrations, particularly changes in field curvature during vibration reduction and decentering coma, can be effectively corrected throughout the entire zoom range.

[0062] Note that by setting the lower limit of conditional expression (13) to 0.085, the effects of the first or second embodiment can be more reliably achieved. Also, in order to more reliably achieve the effects of the first or second embodiment, the lower limit of conditional expression (13) is preferably set to 0.090, and more preferably set to 0.095, 0.100, 0.105, 0.112, 0.116, or even 0.118.

[0063] On the other hand, by setting the upper limit of conditional expression (13) to 0.45, the effects of the first or second embodiment can be more reliably achieved. Also, in order to more reliably achieve the effects of the first or second embodiment, it is preferable to set the upper limit of conditional expression (13) to 0.40, and it is even more preferable to set it to 0.35, 0.30, 0.25, 0.20, 0.17, 0.15, or 0.14.

[0064] In the zoom lens ZL of the first or second embodiment, it is desirable that the rear group GR includes a vibration-reduction lens group Gv and that three or more lenses are located closer to the object side than the vibration-reduction lens group Gv. This configuration makes it possible to suppress decentering coma aberrations and the like during vibration reduction.

[0065] It is also desirable that the zoom lens ZL of the first or second embodiment satisfy the following condition: 1.20<LRw / LFw<2.80 (14) where LRw is the distance from the lens surface of the rear group closest to the object to the lens surface of the front group closest to the image in the wide-angle end state, and LFw is the distance from the lens surface of the front group closest to the object to the lens surface of the front group closest to the image in the wide-angle end state.

[0066] Conditional expression (14) defines the ratio between the distance from the lens surface of the rear group closest to the object to the lens surface closest to the image in the wide-angle end state and the distance from the lens surface of the front group closest to the object to the lens surface closest to the image in the wide-angle end state. By satisfying conditional expression (14), various aberrations, particularly coma and curvature of field at the wide-angle end, and spherical aberration and coma at the telephoto end, can be effectively corrected.

[0067] Note that by setting the lower limit of conditional expression (14) to 1.30, the effects of the first or second embodiment can be more reliably achieved. In order to further ensure the effects of the first or second embodiment, the lower limit of conditional expression (14) is preferably set to 1.40, and more preferably set to 1.50, 1.60, 1.70, 1.80, 1.90, 2.00, or 2.10.

[0068] On the other hand, by setting the upper limit of conditional expression (14) to 2.70, the effects of the first or second embodiment can be more reliably achieved. Also, in order to more reliably achieve the effects of the first or second embodiment, it is preferable to set the upper limit of conditional expression (14) to 2.60, and it is even more preferable to set it to 2.50, 2.45, 2.41, 2.37, 2.33, or 2.30.

[0069] Furthermore, it is desirable that the zoom lens ZL of the first or second embodiment has an aperture diaphragm S, the rear group GR has an image stabilizing lens group Gv, and the aperture diaphragm S is located closer to the object side than the image stabilizing lens group Gv. This configuration enables excellent correction of various aberrations, particularly field curvature, decentering coma, etc., throughout the entire zoom range.

[0070] It is also desirable that the zoom lens ZL of the first or second embodiment satisfy the following condition: 4.00<r1 / fw (15) where r1 is the radius of curvature of the lens surface of the zoom lens closest to the object side.

[0071] Conditional expression (15) defines the ratio between the radius of curvature of the lens surface closest to the object side of the zoom lens and the focal length of the zoom lens at the d-line in the wide-angle end state. By satisfying conditional expression (15), it is possible to ensure peripheral illumination while reducing the size, and to effectively correct various aberrations, particularly field curvature, coma, etc., throughout the entire zoom range.

[0072] Note that by setting the lower limit of conditional expression (15) to 4.50, the effects of the first or second embodiment can be more reliably achieved. In order to further ensure the effects of the first or second embodiment, the lower limit of conditional expression (15) is preferably set to 5.00, and more preferably set to 5.50, 6.00, 6.50, 7.00, 7.20, or even 7.40.

[0073] On the other hand, by setting the upper limit of conditional expression (15) to "<100.00," the effects of the first or second embodiment can be more reliably achieved. Also, in order to more reliably achieve the effects of the first or second embodiment, it is preferable that the upper limit of conditional expression (15) be set to 50.00, and more preferably to 30.00, 20.00, 15.00, 13.00, 11.00, 10.00, 9.00, or even 8.70.

[0074] In the zoom lens ZL of the first or second embodiment, it is desirable that the front group GF has three or more lenses, the image-side surface of the third lens from the image side and the object-side surface of the second lens from the image side have concave surfaces facing each other, and that the following condition be satisfied: −1.00 < (ra+rb) / (ra−rb) < 1.00 (16) where ra: radius of curvature of the image-side surface of the third lens from the image side in the front group, rb: radius of curvature of the object-side surface of the second lens from the image side in the front group.

[0075] Conditional expression (16) defines the shape factor of the radius of curvature of the image-side surface of the third lens element closest to the image in the front group and the radius of curvature of the object-side surface of the second lens element closest to the image in the front group. By satisfying conditional expression (16), various aberrations, particularly field curvature, coma, etc., can be effectively corrected throughout the entire zoom range.

[0076] Note that by setting the lower limit of conditional expression (16) to −0.90, the effects of the first or second embodiment can be more reliably achieved. In order to further ensure the effects of the first or second embodiment, the lower limit of conditional expression (16) is preferably set to −0.80, and more preferably to −0.70, −0.60, −0.50, −0.45, −0.40, −0.38, −0.35, or further preferably to −0.33.

[0077] On the other hand, by setting the upper limit of conditional expression (16) to 0.80, the effects of the first or second embodiment can be more reliably achieved. Also, in order to more reliably achieve the effects of the first or second embodiment, it is preferable to set the upper limit of conditional expression (16) to 0.60, and it is even more preferable to set it to 0.40, 0.20, 0.00, −0.10, −0.20, −0.25, or further −0.31.

[0078] It is also desirable that the zoom lens ZL of the first or second embodiment satisfy the following condition: 0.20<Bfaw / (-fFw)<1.50 (17) where Bfaw is the air-equivalent back focus of the zoom lens in the wide-angle end state, and fFw is the focal length of the front group with respect to the d-line in the wide-angle end state.

[0079] Conditional expression (17) defines the ratio of the air-equivalent back focus of the zoom lens in the wide-angle end state to the focal length of the front group at the d-line in the wide-angle end state. By satisfying conditional expression (17), various aberrations, particularly coma and curvature of field at the wide-angle end, and spherical aberration and coma at the telephoto end, can be effectively corrected.

[0080] Note that by setting the lower limit of conditional expression (17) to 0.30, the effects of the first or second embodiment can be more reliably achieved. In order to further ensure the effects of the first or second embodiment, the lower limit of conditional expression (17) is preferably set to 0.40, and more preferably set to 0.45, 0.50, 0.55, 0.58, or even 0.60.

[0081] On the other hand, by setting the upper limit of conditional expression (17) to 1.30, the effect of the first or second embodiment can be more reliably achieved. Also, in order to more reliably achieve the effect of the first or second embodiment, it is preferable to set the upper limit of conditional expression (17) to 1.20, and it is even more preferable to set it to 1.10, 1.00, 0.90, 0.85, 0.80, 0.77, 0.75, or 0.73.

[0082] It is also desirable that the zoom lens ZL of the first or second embodiment satisfy the following condition: 0.40<Bfaw / fw<3.00 (18) where Bfaw is the air-equivalent back focus of the zoom lens in the wide-angle end state.

[0083] Conditional expression (18) defines the ratio of the air-equivalent back focus of the zoom lens in the wide-angle end state to the focal length of the zoom lens at the d-line in the wide-angle end state. By satisfying conditional expression (18), various aberrations, particularly coma and curvature of field at the wide-angle end, and spherical aberration and coma at the telephoto end, can be effectively corrected.

[0084] Note that by setting the lower limit of conditional expression (18) to 0.50, the effects of the first or second embodiment can be more reliably achieved. In order to further ensure the effects of the first or second embodiment, the lower limit of conditional expression (18) is preferably set to 0.60, and more preferably set to 0.70, 0.80, 0.90, 1.00, 1.10, 1.20, or 1.25.

[0085] On the other hand, by setting the upper limit of conditional expression (18) to 2.80, the effects of the first or second embodiment can be more reliably achieved. Also, in order to more reliably achieve the effects of the first or second embodiment, it is preferable to set the upper limit of conditional expression (18) to 2.60, and more preferably to 2.40, 2.20, 2.00, 1.80, 1.70, 1.60, 1.55, or even 1.50.

[0086] It is also desirable that the zoom lens ZL of the first or second embodiment satisfy the following condition: 40.00<ωw<80.00 (19) where ωw is the half angle of view of the zoom lens in the wide-angle end state (unit: degrees).

[0087] Condition (19) defines the half angle of view of the zoom lens in the wide-angle end state. By satisfying condition (19), it is possible to obtain good optical performance with various aberrations corrected despite the compact size.

[0088] Note that by setting the lower limit of conditional expression (19) to 42.00, the effects of the first or second embodiment can be more reliably achieved. Also, in order to more reliably achieve the effects of the first or second embodiment, it is preferable that the lower limit of conditional expression (19) be 44.00, and more preferably 46.00, 48.00, 50.00, 52.00, 54.00, 56.00, or 58.00.

[0089] On the other hand, by setting the upper limit of conditional expression (19) to 77.00, the effects of the first or second embodiment can be more reliably achieved. Also, in order to more reliably achieve the effects of the first or second embodiment, it is preferable to set the upper limit of conditional expression (19) to 74.00, and more preferably to 72.00, 70.00, 68.00, 66.00, 65.00, 64.00, or 63.00.

[0090] It is also desirable that the zoom lens ZL of the first or second embodiment satisfy the following condition: 30.00<ωt<55.00 (20), where ωt is the half angle of view of the zoom lens in the telephoto end state (unit: degrees).

[0091] Condition (20) defines the half angle of view of the zoom lens in the telephoto end state. By satisfying condition (20), it is possible to obtain good optical performance with various aberrations corrected despite the compact size.

[0092] Note that by setting the lower limit of conditional expression (20) to 32.00, the effects of the first or second embodiment can be more reliably achieved. In order to further ensure the effects of the first or second embodiment, the lower limit of conditional expression (20) is preferably set to 34.00, and more preferably set to 36.00, 37.00, 38.00, 39.00, or even 40.00.

[0093] On the other hand, by setting the upper limit of conditional expression (20) to 52.00, the effects of the first or second embodiment can be more reliably achieved. Also, in order to more reliably achieve the effects of the first or second embodiment, it is preferable to set the upper limit of conditional expression (20) to 50.00, and more preferably to 48.00, 47.00, 46.00, 45.00, 44.00, 43.00, or 42.00.

[0094] The optical apparatus according to this embodiment includes the zoom lens ZL having the above-described configuration, thereby making it possible to realize an optical apparatus that is compact yet includes the zoom lens ZL, which has good optical performance in which various aberrations are corrected from the wide-angle end state to the telephoto end state.

[0095] An example of a camera (optical device) equipped with the zoom lens ZL of this embodiment will now be described. Fig. 22 is a diagram showing an example of the configuration of a camera 1 equipped with the zoom lens ZL.

[0096] As shown in FIG. 22 , camera 1 is a so-called mirrorless camera with an interchangeable lens system that includes a zoom lens ZL as a photographing lens 2. In camera 1, light from an object (subject) (not shown) is condensed by photographing lens 2 and passes through an OLPF (optical low pass filter) (not shown) to form a subject image on the imaging surface of imaging unit 3. The subject image is then photoelectrically converted by a photoelectric conversion element provided in imaging unit 3 to generate an image of the subject. This image is displayed on an EVF (electronic viewfinder) 4 provided in camera 1. This allows the photographer to observe the subject through EVF 4. Furthermore, when the photographer presses a release button (not shown), the image of the subject generated by imaging unit 3 is stored in a memory (not shown). In this manner, the photographer can photograph the subject using camera 1.

[0097] As will be apparent from the examples described below, the zoom lens ZL provided in the camera 1 as the photographing lens 2 has a distinctive lens configuration that, despite its compact size, provides excellent optical performance in which various aberrations are corrected from the wide-angle end state to the telephoto end state. Therefore, the camera 1 can realize an optical device that includes a zoom lens ZL that, despite its compact size, provides excellent optical performance in which various aberrations are corrected from the wide-angle end state to the telephoto end state.

[0098] Although a mirrorless camera has been described as an example of the camera 1, the optical device of this embodiment is not limited to this. For example, the same effects as those of the camera 1 can be achieved even if the above-described zoom lens ZL is provided on a single-lens reflex camera that has a quick-return mirror in the camera body and observes a subject through a viewfinder optical system.

[0099] A manufacturing method for a zoom lens ZL of the first embodiment relating to a fourth aspect is a manufacturing method for a zoom lens ZL which is composed of, in order from the object side, a front group GF and a rear group GR, the front group GF and the rear group GR being separated by the longest air gap in the optical system in the wide-angle end state, the front group GF having negative refractive power at least in the wide-angle end state, the rear group GR having positive refractive power at least in the wide-angle end state, and which is composed of a plurality of lens groups whose adjacent air gaps change during magnification, the lens group closest to the object side having positive refractive power, and which is configured to satisfy the following conditional expression: 1.90 < (-fFw) / fw < 4.00 (1) where, fFw: focal length of the front group with respect to the d-line in the wide-angle end state fw: focal length of the zoom lens with respect to the d-line in the wide-angle end state

[0100] This makes it possible to manufacture a zoom lens ZL that is compact yet has good optical performance in which various aberrations are corrected from the wide-angle end state to the telephoto end state.

[0101] A manufacturing method for the zoom lens ZL according to the first embodiment will be outlined below with reference to Fig. 23. First, the zoom lens is arranged so that, in order from the object side, it is composed of a front group GF and a rear group GR, the front group GF and the rear group GR are separated by the longest air gap in the optical system in the wide-angle end state, the front group GF has negative refractive power at least in the wide-angle end state, the rear group GR has positive refractive power at least in the wide-angle end state, and the zoom lens is composed of multiple lens groups whose adjacent air gaps change during magnification, with the lens group closest to the object side having positive refractive power (S1). Next, the zoom lens ZL is arranged so as to satisfy a predetermined conditional expression (S2).

[0102] According to the above-described method for manufacturing the zoom lens ZL, it is possible to manufacture a zoom lens ZL that is compact yet has good optical performance in which various aberrations are corrected from the wide-angle end state to the telephoto end state.

[0103] Furthermore, a manufacturing method for a zoom lens ZL of a second embodiment relating to a fifth aspect is a manufacturing method for a zoom lens having an image stabilizing lens group Gv, the zoom lens ZL being composed of, in order from the object side, a front group GF and a rear group GR, the front group GF and the rear group GR being separated by the longest air gap within the optical system in the wide-angle end state, the front group GF having negative refractive power at least in the wide-angle end state, the rear group GR having positive refractive power at least in the wide-angle end state and composed of a plurality of lens groups whose adjacent air gaps change during magnification, the lens group closest to the object side having positive refractive power, the rear group GR being composed so as to satisfy the following conditional expression: 10.0 < |fv| / fw < 30.0 (4) 0.50 < Lvw / LRw < 0.80 (5) where, fv: focal length of the vibration-reduction lens group relative to the d-line fw: focal length of the zoom lens relative to the d-line in the wide-angle end state Lvw: distance from the lens surface of the vibration-reduction lens group closest to the image in the wide-angle end state to the lens surface of the entire system closest to the image LRw: distance from the lens surface of the rear group closest to the object in the wide-angle end state to the lens surface of the entire system closest to the image

[0104] This makes it possible to manufacture a zoom lens ZL that is compact yet has good optical performance in which various aberrations are corrected from the wide-angle end state to the telephoto end state.

[0105] A manufacturing method for the zoom lens ZL according to the second embodiment will be outlined below with reference to Fig. 24. First, the zoom lens ZL is arranged (S1) so that, from the object side, it is composed of a front group GF and a rear group GR, the front group GF and the rear group GR being separated by the longest air gap within the optical system in the wide-angle end state, the front group GF having negative refractive power at least in the wide-angle end state, the rear group GR having positive refractive power at least in the wide-angle end state, and being composed of multiple lens groups whose adjacent air gaps change during magnification, the lens group closest to the object side having positive refractive power, and the rear group GR including the vibration-reduction lens group Gv. Next, the zoom lens ZL is arranged (S2) so that a predetermined conditional expression is satisfied.

[0106] According to the above-described method for manufacturing a zoom lens, it is possible to manufacture a zoom lens ZL that is compact yet has good optical performance in which various aberrations are corrected from the wide-angle end state to the telephoto end state.

[0107] It should be noted that the conditions and configurations described above each exert the effects described above, and are not limited to those that satisfy all of the conditions and configurations; the effects described above can be obtained by satisfying any one of the conditions or configurations, or any combination of the conditions or configurations.

[0108] Furthermore, the examples described below are merely examples of the present invention, and the present invention is not limited to these. The following content can be appropriately adopted within the scope that does not impair the optical performance of the optical system of this embodiment.

[0109] For example, while the following examples illustrate zoom lenses with four, five, or six lens groups as numerical examples, the present embodiment is not limited to these examples, and other lens group configurations (e.g., three, seven, or eight lens groups) may also be used. While the front lens group is illustrated as having one or two lens groups, other lens group configurations (e.g., three, four, or eight lens groups) may also be used. Although the rear lens group is illustrated as having three, four, or five lens groups, other lens group configurations (e.g., two, six, or seven lens groups) may also be used. Specifically, the zoom lenses of the following examples may have an additional lens or lens group closest to the object or image. Alternatively, an additional lens or lens group may be used between adjacent lens groups. In this specification, a lens group refers to a portion having at least one lens separated by an air gap that changes during zooming. However, any lens group may be used as long as it is made up of at least one or more lenses separated by an air gap.

[0110] The focusing lens group can also be applied to autofocusing, and is suitable for driving a motor for autofocusing (for example, an ultrasonic motor, a stepping motor, a VCM motor, etc.). Furthermore, as an anti-vibration lens group, a lens group or a partial lens group may be moved so as to have a displacement component perpendicular to the optical axis, or may be rotated (oscillated) in a plane including the optical axis to correct image blur caused by camera shake or the like. Image blur correction, which moves the imaging element so as to have a displacement component perpendicular to the optical axis, may also be used in combination, but the anti-vibration lens group method is preferred because it does not cause image distortion during correction.

[0111] The lens surface may be spherical, flat, or aspherical. A spherical or flat lens surface is preferred because it facilitates lens processing and assembly adjustment and prevents degradation of optical performance due to errors in processing and assembly adjustment. It is also preferred because it minimizes degradation of imaging performance even when the image plane is misaligned. If the lens surface is aspherical, the aspherical surface may be any of the following aspherical surfaces: a ground aspherical surface, a glass-molded aspherical surface in which glass is molded into an aspherical shape, or a hybrid aspherical surface in which a resin is molded into an aspherical shape on the surface of glass. The lens surface may also be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

[0112] The aperture stop S is preferably located inside or outside the lens group, but the lens frame may serve the role of an aperture stop instead of providing a component. Furthermore, each lens surface may be coated with an anti-reflection coating that has high transmittance over a wide wavelength range in order to reduce flare and ghosting and achieve high-contrast optical performance.

[0113] With the above-described configuration, it is possible to provide a zoom lens ZL that is compact yet has good optical performance in which various aberrations are corrected from the wide-angle end state to the telephoto end state, and an optical apparatus that includes this zoom lens ZL.

[0114] Each example according to this embodiment will be described below with reference to the drawings. Tables 1 to 7 are tables showing the specifications of the first to seventh examples.

[0115] The zoom lenses ZL according to the examples of each embodiment will be described below with reference to the drawings. Figures 1, 4, 7, 10, 13, 16, and 19 are cross-sectional views showing the configuration and refractive power distribution of the zoom lenses ZL (ZL(1) to ZL(7)) according to the first to seventh examples.

[0116] In the cross-sectional views of the zoom lenses ZL(1) to ZL(7) according to the first to seventh embodiments, with the left side of the zoom lens being the object side and the right side being the image side, the wide-angle end state (w) is shown at the top of the page and the telephoto end state (t) is shown at the bottom, with arrows between them indicating the movement trajectory of each lens group along the optical axis when changing magnification. The focusing lens group that focuses from infinity to a close-up object is indicated as Gf, and the direction of movement along the optical axis from focusing at infinity to focusing at close distances is indicated by an arrow. The vibration-proof lens group is indicated as Gv.

[0117] 1, 4, 7, 10, 13, 16, and 19, each lens group is designated by a combination of a symbol G and a number, starting from the object side, as G1, G2, G3, and so on, and each lens is designated by a combination of a symbol L and a number, starting from the object side, as L11, L12, L13, and so on. In this case, to prevent the number and types of symbols and numbers from increasing and becoming cumbersome, each example uses its own independent combination of symbols and numbers to represent the lens groups, etc. Therefore, even if the same combination of symbols and numbers is used between examples, it does not mean that the examples have the same configuration.

[0118] Furthermore, Figures 2, 5, 8, 11, 14, 17, and 20 are aberration diagrams for each Example when the lens is focused at infinity at the wide-angle end (w), and Figures 3, 6, 9, 12, 15, 18, and 21 are aberration diagrams for each Example when the lens is focused at infinity at the telephoto end (t), which show that aberrations are well corrected. Here, 1-pos indicates infinity at the wide-angle end (when the lens is focused at infinity at the wide-angle end), 2-pos indicates infinity at the telephoto end (when the lens is focused at infinity at the telephoto end), FNo indicates the F-number, Y indicates the image height, and d and g indicate the aberration curves for the d-line and g-line, respectively. Regarding astigmatism, the solid line indicates the sagittal image plane, and the dotted line indicates the meridional image plane.

[0119] In each embodiment, the C-line (wavelength 656.3 nm), d-line (wavelength 587.6 nm), F-line (wavelength 486.1 nm), and g-line (wavelength 435.8 nm) are selected as the targets for calculating the aberration characteristics.

[0120] In the table (basic specifications), f is the focal length of the entire zoom lens ZL system, FNo is the F-number, ω is the half angle of view (maximum angle of incidence in degrees), Y is the image height, Bf is the back focus (the actual distance from the final lens surface on the optical axis to the paraxial image plane), Bfa (air-equivalent length) is the back focus (the distance from the final lens surface on the optical axis to the paraxial image plane converted into air), TL is the total lens length (the distance from the frontmost lens surface to the final lens surface on the optical axis plus Bf), and TLa is the total lens length (the distance from the frontmost lens surface to the final lens surface on the optical axis plus Bfa).

[0121] In the table, (surface data), the surface number indicates the order of the optical surface from the object side along the direction of light ray travel, r indicates the radius of curvature of each optical surface, d indicates the surface spacing, which is the distance on the optical axis from each optical surface to the next optical surface (or image plane), nd indicates the refractive index of the optical element material relative to the d-line, and νd indicates the Abbe number of the optical element material relative to the d-line. Furthermore, (object surface) indicates the object surface, (variable) indicates a variable surface spacing, a radius of curvature of "0" or "∞" indicates a plane or aperture, (aperture) indicates the aperture stop S, the image plane indicates the image plane I, and Bf indicates the back focus (the distance from the final surface on the optical axis to the paraxial image plane). Even if Bf is not marked as (variable), it may be variable. The refractive index of air, "1.00000," is omitted.

[0122] In the (aspherical surface data) in the table, the aspherical surface is expressed by the following formula (a), where y is the height in the direction perpendicular to the optical axis, S(y) is the distance along the optical axis from the tangent plane of the vertex of each aspherical surface at the height y to each aspherical surface (amount of sag), r is the radius of curvature of the reference spherical surface (paraxial radius of curvature), κ is the conic constant, and An is the aspherical coefficient of the nth order (n=4, 6, 8, 10, 12, 14, 16). Note that in the following examples, "E-n" is "×10 -n " For example, "6.04637E-06" means "6.04637 x 10 －６ " indicates.

[0123] S(y)=(y2 / r) / {1+(1-κ×y 2 / r 2 ) 1 / 2 +A4×y 4 +A6×y 6 +A8×y 8 +A10×y 10 +A12×y 12 +A14×y 14 +A16×y 16 (a)

[0124] In each example, the second-order aspherical coefficient A2 is omitted because it is 0. In the table of each example, aspherical surfaces are marked with an asterisk (*) to the right of the surface number.

[0125] In the table (lens group focal length), the first surface indicates the surface number of each group closest to the object, the last surface indicates the surface number of each group closest to the image, and the group focal length indicates the focal length of each group.

[0126] In the table, (variable distance data) indicates 1-pos, 2-pos, 3-pos, and 4-pos, i.e., each variable distance di at infinity at the wide-angle end (infinity focused at the wide-angle end), infinity at the telephoto end (infinity focused at the telephoto end), close range at the wide-angle end (close range focused at the wide-angle end), and close range at the telephoto end (close range focused at the telephoto end). Here, di indicates the variable distance between the ith surface and the (i+1)th surface. Note that the magnification indicates the imaging magnification at the close range.

[0127] In the following, for all specification values, the focal length f, radius of curvature r, surface spacing d, and other lengths are generally expressed in "mm" unless otherwise specified, but this is not limited to this because the same optical performance can be obtained even when the optical system is proportionally enlarged or reduced. Furthermore, the unit is not limited to "mm" and other appropriate units can be used.

[0128] The explanation of the tables up to this point is common to all the embodiments, and will not be repeated below.

[0129] 1 is a cross-sectional view of a zoom lens ZL according to Example 1. The zoom lens ZL according to this example is composed of, in order from the object side, a front group GF that has negative refractive power at least in the wide-angle end state, an aperture stop S, and a rear group GR that has positive refractive power at least in the wide-angle end state, and the front group GF and the rear group GR are separated by air gaps d9 and d10, which are the longest in the optical system in the wide-angle end state.

[0130] The front group GF is composed of, in order from the object side, a first lens group G1 having negative refractive power. Here, the first lens group G1 is composed of a negative meniscus lens L11 with a convex surface facing the object side, a negative meniscus lens L12 with a convex surface facing the object side, a biconcave negative lens L13, and a biconvex positive lens L14. The image-side surface of the negative lens L11 is aspherical, and the object-side surface of the negative lens L12 is formed with an aspherical resin layer. The focal length of the negative lens L11 closest to the object in the front group GF is fg1, and the focal length of the second negative lens L12 is fg2. The radius of curvature of the image-side surface of the third lens L12 closest to the image in the front group GF is ra, and the radius of curvature of the object-side surface of the second lens L13 is rb. The rear group GR is composed of, in order from the object side, a second lens group G2 having positive refractive power, a third lens group G3 having positive refractive power, and a fourth lens group G4 having negative refractive power. Here, the second lens group G2 is composed of a biconvex positive lens L21, a cemented lens of a biconcave negative lens L22 and a meniscus positive lens L23 with its convex surface facing the object side, a biconvex positive lens L24, a cemented negative lens of a biconvex positive lens L25 and a biconcave negative lens L26, and a cemented lens of a biconvex positive lens L27 and a biconcave negative lens L28. The third lens group G3 is composed of a biconvex positive lens L31, a biconvex positive lens L32, and a meniscus positive lens L33 with its convex surface facing the object side. The fourth lens group G4 is composed of a cemented lens of a meniscus positive lens L41 with its concave surface facing the object side and a biconcave negative lens L42, and a biconvex positive lens L43, and the object side surface of the positive lens L43 is aspherical. The vibration-reduction lens group is made up of cemented lenses L25 and L26 in the second lens group G2, which have negative refractive power, and the object side of the vibration-reduction lens group has four lenses L21-L24. The focusing lens group is made up of third lens group G3, which has positive refractive power and moves toward the object side when focusing from infinity to a close distance. A filter group FL, such as a low-pass filter, is disposed between the rear group GR and the image plane I. An image sensor (not shown), such as a CCD or CMOS, is disposed on the image plane I.

[0131] An image is formed on an image plane I by this zoom lens ZL, and photography is performed. The zoom lens ZL and the image plane I of the zoom lens ZL are shown in Figure 1. Table 1 below shows the values ​​of each parameter in the first embodiment.

[0132] (Table 1) First Example (Basic specifications) Wide-angle end infinity Telephoto end infinity f 8.2400 15.5200 FNo 2.9000 2.9000 ω 61.93843 40.63358 TL 123.8831 105.1307 TLa (equivalent length in air) 123.3379 104.5855 Bf 0.1008 0.1008 Bfa (equivalent length in air) 10.85962 19.07960 fF (focal length of front group G1) -16.6386 -16.6386 fR (focal length of rear group G2-G4) 27.1265 24.9513 fR1 (focal length of rear group G2, closest to the object) 47.4234 fg1 (focal length of L11) -17.0816 fg2 (focal length of L12) -67.3427 ff (focal length of focusing lens group G3) 20.0327 fv (focal length of image-stabilizing lens groups L25 and L26) -128.725 fvR (composite focal length of lenses L27-L43 located closer to the image than the image-stabilizing lens groups) 60.6108 57.9462 LF (distance r1-r9 from the lens surface closest to the object in the front group to the lens surface closest to the image) 25.9647 25.9647 LR (distance r11-r34 from the lens surface closest to the object in the rear group to the lens surface closest to the image in the entire system) 55.8806 56.3434 Lv (distance r20-r34 from the lens surface closest to the image in the image-stabilizing lens group to the lens surface closest to the image in the entire system) 34.1773 34.64 Lf (distance r29-r34 from the lens surface closest to the image in the focusing lens group to the lens surface closest to the image in the entire system when focused at infinity) 11.4084 13.4908 r1 (radius of curvature of the lens surface closest to the object) 67.4027 ra (radius of curvature of the image-side surface r5 of the third lens element from the image side in the front group) 15.4669 rb (radius of curvature of the image-side surface r6 of the second lens element from the image side in the front group) -29.9668 (Surface data) Surface number rd nd νd 0 (object surface)∞ (variable) 1 67.4027 3.2000 1.820980 42.50 *2 11.3600 5.4879 *3 20.7968 0.4704 1.553890 38.09 4 30.0000 1.8000 1.804000 46.60 5 15.4669 8.7368 6 -29.9668 1.3000 1.593190 67.90 7 93.1029 0.1000 8 44.6032 4.8696 1.688930 31.16 9 -39.8268 d9 S10 (Aperture) ∞ 1.2000 11 35.1476 3.6418 1.708626 31.32 12 -18.5771 0.4276 13 -16.1581 1.3000 1.919335 35.91 14 16.0326 3.0652 1.770231 31.97 15 90.5560 0.4861 16 30.4783 5.0897 1.552000 70.70 17 -18.3387 2.0000 18 29.5640 4.3928 1.628312 37.17 19 -79.7361 1.3000 1.902650 35.77 20 32.5780 1.0000 21 26.8991 5.5900 1.497820 82.57 22 -12.2497 1.3000 1.902650 35.77 23 152.9903 d23 24 49.0655 5.9185 1.497820 82.57 25 -19.6807 0.1000 26 99.4610 2.2935 1.497820 82.57 27 -148.4318 0.1000 28 41.4978 2.2298 1.518600 69.89 29 122.2666 d29 30 -300.0000 4.9880 1.805180 25.45 31 -14.7930 1.3000 1.929104 34.86 32 56.7085 1.7132 *33 2692.0115 1.8000 1.851080 40.12 34 -321.4582 d34 35 0.0000 1.6000 1.516800 63.88 36 0.0000 0.1008 Image surface ∞ (Aspheric data) Surface κ A4 A6 A8 A10 2 -0.3460 6.04637E-06 3.09036E-08 -2.44424E-10 -3.39984E-13 3 -4.0068 1.58892E-05 -1.18810E-07 3.76989E-11 1.23267E-13 33 1.0000 -5.28364E-05 -2.45941E-07 1.20760E-09 -1.28578E-11 (Lens group focal length) Lens group Initial surface Final surface group focal length GF 1 9 -16.6386 (Wide-angle end) -16.6386 (Telephoto end) G1 1 9 -16.6386 GR 11 34 27.1265 (Wide-angle end) 24.9513 (Telephoto end) G2 11 23 47.4234 G3 24 29 20.0327 G4 30 34 -40.763 (Variable interval data) Wide-angle end Infinite telephoto end Infinite wide-angle end Close distance Telephoto end Close distance 1-pos 2-pos 3-pos 4-pos f 8.2400 15.5200 - - Magnification - - -0.020 -0.020 d9 29.43295 1.99787 29.43295 1.99787 d23 4.23721 2.61754 4.14704 2.48262 d29 1.60712 3.68953 1.69729 3.82445 d34 9.70396 17.92394 9.70396 17.92394 .

[0133] FIGS. 2 and 3 are diagrams showing various aberrations of the zoom lens ZL of Example 1 when focused at infinity at the wide-angle end and when focused at infinity at the telephoto end, respectively, and show that various aberrations are well corrected, resulting in excellent imaging performance.

[0134] 4 is a cross-sectional view of a zoom lens ZL according to Example 2. The zoom lens ZL according to Example 2 is composed of, in order from the object side, a front group GF having negative refractive power at least in the wide-angle end state, an aperture stop S, and a rear group GR having positive refractive power at least in the wide-angle end state, and the front group GF and the rear group GR are separated by air gaps d9 and d10, which are the longest in the optical system in the wide-angle end state.

[0135] The front group GF is composed of, in order from the object side, a first lens group G1 having negative refractive power. Here, the first lens group G1 is composed of a negative meniscus lens L11 with a convex surface facing the object side, a negative meniscus lens L12 with a convex surface facing the object side, a biconcave negative lens L13, and a biconvex positive lens L14. The image-side surface of the negative lens L11 is aspherical, and the object-side surface of the negative lens L12 is formed with an aspherical resin layer. The focal length of the negative lens L11 closest to the object in the front group GF is fg1, and the focal length of the second negative lens L12 is fg2. The radius of curvature of the image-side surface of the third lens L12 closest to the image in the front group GF is ra, and the radius of curvature of the object-side surface of the second lens L13 is rb. The rear group GR is composed of, in order from the object side, a second lens group G2 having positive refractive power, a third lens group G3 having negative refractive power, and a fourth lens group G4 having positive refractive power, wherein the second lens group G2 comprises a positive lens L21 having a meniscus shape with a convex surface facing the object side, a cemented lens of a negative lens L22 having a meniscus shape with a convex surface facing the object side and a positive lens L23 having a meniscus shape with a convex surface facing the object side, a biconvex positive lens L24, a cemented positive lens of a positive lens L25 having a meniscus shape with a concave surface facing the object side and a negative lens L26 having a meniscus shape with a concave surface facing the object side, a biconvex positive lens L27 and a meniscus The third lens group G3 is composed of a biconcave negative lens L31 and a meniscus-shaped positive lens L32 with a convex surface facing the object side, and the fourth lens group G4 is composed of a biconvex positive lens L41, a cemented lens of a meniscus-shaped positive lens L42 with a concave surface facing the object side and a biconcave negative lens L43, and a meniscus-shaped negative lens L44 with a convex surface facing the object side, the object-side surface of the negative lens L44 being aspherical. The vibration-proof lens group is composed of cemented lenses L25 and L26 in the second lens group G2, which have positive refractive power, and the object side of the vibration-proof lens group includes four lenses L21-L24. The focusing lens group is the third lens group G3, which has negative refractive power and moves toward the image side when focusing from infinity to a close distance. A filter group FL including a low-pass filter or the like is disposed between the rear group GR and the image plane I.An image pickup element (not shown) made up of a CCD, CMOS, or the like is disposed on the image plane I.

[0136] An image is formed on an image plane I by this zoom lens ZL, and photography is performed. The zoom lens ZL and the image plane I of the zoom lens ZL are shown in Figure 4. Table 2 below shows the values ​​of each parameter in the second embodiment.

[0137] (Table 2) Second Example (Basic Parameters) Wide-angle end at infinity, far-angle end at infinity f 8.2400 15.5200 FNo 2.9000 2.9000 ω 61.93843 40.63358 TL 115.0037 95.3088 TLa (Air Conversion Length) 114.4586 94.7636 Bf 0.1043 0.1043 Bfa (Air Conversion Length) 11.84163 21.86933 fF(G1) -18.2415 -18.2415 fR(G2-G4) 25.816 24.5746 fR1(G2) 19.722 fg1(L11) -16.4336 fg2(L12) -66.9092 ff(G3) -23.032 fv(L25,26) 167.218 fvR(L27-L44) 69.1499 70.0545 LF(r1-r9) 26.6284 26.6284 LR(r11-r33) 45.8223 43.5618 Lv(r20-r33) 30.5831 28.3225 Lf(r26-r33) 18.3517 15.7929 r1 63.2766 ra(r5) 15.2602 rb(r6) -32.6398 (Men Data) Men Number rd nd νd 0(object surface)∞ (can be changed) 1 63.2766 3.2000 1.851080 40.12 *2 11.1881 5.9082 *3 20.3395 0.4704 1.553890 38.09 4 30.0000 1.8000 1.806100 40.98 5 15.2602 8.5345 6 -32.6398 1.4000 1.593190 67.90 7 130.3688 0.1000 8 39.9730 5.2153 1.688930 31.16 9 -43.1283 d9 S10 (aperture stop)∞ 1.2000 11 41.8208 1.8796 1.688930 31.16 12 147.4486 0.1000 13 48.1582 1.4000 1.953750 32.33 14 15.0185 3.0607 1.698950 30.13 15 98.2057 0.2843 16 31.5534 2.3609 1.497820 82.57 17 -596.6364 2.0000 18 -143.5627 2.7537 1.563840 60.71 19 -20.8519 1.4000 1.902650 35.77 20 -35.1131 1.0000 21 27.9108 4.6406 1.497820 82.57 22 -15.3599 1.4000 1.883000 40.69 23 -22.0713 d23 24 -50.6888 1.4000 1.893640 39.12 25 20.5962 2.5908 1.497820 82.57 26 84.8590 d26 27 21.9561 5.8390 1.593190 67.90 28 -28.5567 0.1000 29 -253.3941 2.9635 1.593190 67.90 30 -28.2631 1.5000 1.787297 48.04 31 52.2320 1.5394 *32 111.5314 1.5000 1.851080 40.12 33 70.4788 d33 34 0.0000 1.6000 1.516800 63.88 35 0.0000 0.1043 Image surface ∞ (Aspheric data) Surface κ A4 A6 A8 A10 2 -0.9415 7.06452E-05 -2.84215E-07 7.05170E-10 -1.60849E-12 3 -0.7043 -2.36588E-05 -8.09810E-08 2.23400E-10 -2.83626E-13 32 1.0000 -8.34250E-05 -3.33400E-07 -2.42592E-10 -1.42315E-11 (Lens group focal length) Lens group First surface Last surface group focal length GF 1 9 -18.2415 (wide-angle end) -18.2415 (telephoto end) G1 1 9 -18.2415 GR 11 33 25.816 (wide-angle end) 24.5746 (telephoto end) G2 11 23 19.722 G3 24 26 -23.032 G4 27 33 43.0332 (Variable distance data) Wide-angle end Infinity Telephoto end Infinity Wide-angle end Closest distance Telephoto end Closest distance 1-pos 2-pos 3-pos 4-pos f 8.2400 15.5200 - - Magnification - - -0.020 -0.020 d9 28.96629 1.50415 28.96629 1.50415 d23 1.20000 1.49822 1.27782 1.60982 d26 4.90972 2.35097 4.83191 2.23937 d33 10.68250 20.71020 10.68250 20.71020 .

[0138] FIGS. 5 and 6 are diagrams showing various aberrations of the zoom lens ZL of Example 2 when focused at infinity at the wide-angle end and when focused at infinity at the telephoto end, respectively, and show that various aberrations are well corrected, resulting in excellent imaging performance.

[0139] 7 is a cross-sectional view of a zoom lens ZL according to Example 3. The zoom lens ZL according to this example is composed of, in order from the object side, a front group GF that has negative refractive power at least in the wide-angle end state, an aperture stop S, and a rear group GR that has positive refractive power at least in the wide-angle end state, and the front group GF and the rear group GR are separated by air gaps d10 and d11, which are the longest in the optical system in the wide-angle end state.

[0140] The front group GF is composed of, in order from the object side, a first lens group G1 having negative refractive power. Here, the first lens group G1 is composed of a negative meniscus lens L11 with a convex surface facing the object side, a negative meniscus lens L12 with a convex surface facing the object side, a negative meniscus lens L13 with a convex surface facing the object side, a biconcave negative lens L14, and a biconvex positive lens L15, with the negative lens L12 having aspherical surfaces on both sides. The combined focal length of the negative lens L11 closest to the object and the second negative lens L12 in the front group GF is fg1, and the focal length of the third negative lens L13 is fg2. The radius of curvature of the image-side surface of the third lens L13 closest to the image side in the front group GF is ra, and the radius of curvature of the object-side surface of the second lens L14 is rb. The rear group GR is composed of, in order from the object side, a second lens group G2 having positive refractive power, a third lens group G3 having positive refractive power, and a fourth lens group G4 having negative refractive power. The second lens group G2 is composed of a biconvex positive lens L21, a cemented lens of a biconcave negative lens L22 and a meniscus positive lens L23 with its convex surface facing the object side, a biconvex positive lens L24, a cemented negative lens of a biconvex positive lens L25 and a biconcave negative lens L26, and a cemented lens of a biconvex positive lens L27 and a meniscus negative lens L28 with its concave surface facing the object side. The third lens group G3 is composed of a meniscus positive lens L31 with its concave surface facing the object side, a biconvex positive lens L32, and a meniscus positive lens L33 with its convex surface facing the object side. The fourth lens group G4 is composed of a cemented lens of a biconvex positive lens L41 and a biconcave negative lens L42, and a meniscus positive lens L43 with its convex surface facing the object side, with the object side surface of the positive lens L43 being aspherical. The vibration-reduction lens group is made up of cemented lenses L25 and L26 in the second lens group G2, which have negative refractive power, and the object side of the vibration-reduction lens group has four lenses L21-L24. The focusing lens group is made up of third lens group G3, which has positive refractive power and moves toward the object side when focusing from infinity to a close distance. A filter group FL, such as a low-pass filter, is disposed between the rear group GR and the image plane I. An image sensor (not shown), such as a CCD or CMOS, is disposed on the image plane I.

[0141] An image is formed on an image plane I by this zoom lens ZL, and photography is performed. The zoom lens ZL and the image plane I of the zoom lens ZL are shown in Figure 7. Table 3 below shows the values ​​of each parameter in the third embodiment.

[0142] (Table 3) Third Embodiment (Basic Specifications) Wide-angle end: Infinity, Telephoto end: Infinity f 8.2400 15.5200 FNo 2.9000 2.9000 ω 62.57527 40.82781 TL 123.8839 104.4733 TLa (Air equivalent length) 123.3387 103.9282 Bf 0.1000 0.1000 Bfa (Air equivalent length) 11.62007 17.45691 fF(G1) -16.7143 -16.7143 fR(G2-G4) 26.1349 23.7904 fR1(G2) 43.9759 fg1(L11,12) -15.5659 fg2(L13) -148.401 ff(G3) 23.3357 fv(L25,26) -135.013 fvR(L27-L43) 47.3521 40.7537 LF(r1-r10) 26.7765 26.7765 LR(r12-r35) 52.0773 55.5376 Lv(r21-r35) 32.0690 35.5293 Lf(r30-r35) 10.7901 14.5011 r1 69.1516 ra(r6) 18.5097 rb(r7) -33.8821 (Surface Data) Surface number r d nd νd 0(Object surface) ∞ (Variable) 1 69.1516 1.5000 1.806040 40.74 2 22.0000 3.0025 *3 28.0829 1.5000 1.806040 40.74 *4 12.1700 3.2154 5 23.0690 2.2000 1.804000 46.60 6 18.5097 8.3330 7 -33.8821 1.3238 1.593190 67.90 8 36.2465 0.1000 9 34.9966 5.6018 1.688930 31.16 10 -37.9377 d10 S11 (Aperture) ∞ 1.2000 12 24.9107 3.6590 1.688930 31.16 13 -23.1073 0.2377 14 -21.8941 1.3000 1.902650 35.77 15 13.3706 2.6959 1.737999 32.33 16 32.8774 0.1000 17 17.1732 4.6358 1.518600 69.89 18 -29.8425 2.0000 19 45.7538 4.0799 1.620041 36.26 20 -49.7011 1.3000 1.902650 35.77 21 56.0493 1.0000 22 34.1838 6.4544 1.497820 82.57 23 -10.2253 1.3000 1.902650 35.77 24 -48.9708 d24 25 -1789.5597 4.7695 1.497820 82.57 26 -18.9269 0.1000 27 99.4542 2.3076 1.497820 82.57 28 -148.4402 0.1000 29 23.9173 2.3416 1.518600 69.89 30 37.5484 d30 31 64.3346 4.1464 1.805180 25.45 32 -22.6285 1.3000 1.910822 35.25 33 23.2835 1.9437 *34 62.2684 1.8000 1.851080 40.12 35 95.2253 d35 36 0.0000 1.6000 1.516800 63.88 37 0.0000 0.1000 Aspherical Data (Asymmetric Data) A4 A6 A8 A10 3 0.5696 -6.89728E-08 -3.81407E-08 4.52760E-12 9.85487E-14 A12 A14 A16 0.13664E-15 -0.48746E-18 0.98685E-23 A4 A6 A8 A10 4 0.5357 -3.28346E-05 -8.29300E-08 -6.28215E-10 -1.39581E-13 A12 A14 A16 0.29660E-14 0.15676E-16 -0.11524E-18 Face κ A4 A6 A8 A10 34 1.0000 -6.42176E-05 -3.57121E-07 1.35537E-09 -2.59111E-11 (Lens Group Focal Distance) Lens Group Initial and Final Group Focal Distance GF 1 10 -16.7143 (Angle End) -16.7143 (Telescope End) GⅠ 1 10 -16.7143 GR 12 35 26.1349 (Angle End) 23.7904 (Telescope End) GⅡ 12 24 43.9759 G3 25 30 23.3357 G4 31 35 -39.8481 (Variable interval data) Wide-angle end Infinity Telephoto end Infinity Wide-angle end Close distance Telephoto end Close distance 1-pos 2-pos 3-pos 4-pos f 8.2400 15.5200 - - Magnification - - -0.020 -0.020 d10 31.66486 2.95724 31.66486 2.95724 d24 2.90583 2.65501 2.80979 2.51098 d30 1.60000 5.31104 1.69604 5.45507 d35 10.46522 16.30206 10.46522 16.30206.

[0143] FIGS. 8 and 9 are diagrams showing various aberrations of the zoom lens ZL of Example 3 when focused on infinity at the wide-angle end and when focused on infinity at the telephoto end, respectively, and show that various aberrations are well corrected, resulting in excellent imaging performance.

[0144] 10 is a cross-sectional view of a zoom lens ZL according to Example 4. The zoom lens ZL according to this Example is composed of, in order from the object side, a front group GF having negative refractive power at least in the wide-angle end state, an aperture stop S, and a rear group GR having positive refractive power at least in the wide-angle end state, and the front group GF and the rear group GR are separated by air gaps d9 and d10, which are the longest in the optical system in the wide-angle end state.

[0145] The front group GF is composed of, in order from the object side, a first lens group G1 having negative refractive power. Here, the first lens group G1 is composed of a negative meniscus lens L11 with a convex surface facing the object side, a negative meniscus lens L12 with a convex surface facing the object side, a biconcave negative lens L13, and a biconvex positive lens L14. The image-side surface of the negative lens L11 is aspherical, and the object-side surface of the negative lens L12 is formed with an aspherical resin layer. The focal length of the negative lens L11 closest to the object in the front group GF is fg1, and the focal length of the second negative lens L12 is fg2. The radius of curvature of the image-side surface of the third lens L12 closest to the image in the front group GF is ra, and the radius of curvature of the object-side surface of the second lens L13 is rb. The rear group GR is composed of, in order from the object side, a second lens group G2 having positive refractive power, a third lens group G3 having negative refractive power, a fourth lens group G4 having positive refractive power, and a fifth lens group G5 having negative refractive power. Here, the second lens group G2 is composed of a biconvex positive lens L21, a cemented lens of a biconcave negative lens L22 and a meniscus positive lens L23 with its convex surface facing the object side, and a biconvex positive lens L24; the third lens group G3 is composed of a cemented negative lens of a biconvex positive lens L31 and a biconcave negative lens L32, and a cemented lens of a biconvex positive lens L33 and a biconcave negative lens L34; the fourth lens group G4 is composed of a biconvex positive lens L41, a biconvex positive lens L42, and a meniscus positive lens L43 with its convex surface facing the object side; and the fifth lens group G5 is composed of a cemented lens of a meniscus positive lens L51 with its concave surface facing the object side and a biconcave negative lens L52, and a meniscus positive lens L53 with its concave surface facing the object side, with the object side surface of the positive lens L53 being aspherical. The vibration-reduction lens group is made up of cemented lenses L31 and L32 in the third lens group G3, which have negative refractive power, and the object side of the vibration-reduction lens group has four lenses L21-L24. The focusing lens group is made up of fourth lens group G4, which has positive refractive power and moves toward the object side when focusing from infinity to a close distance. A filter group FL, which is made up of a low-pass filter or the like, is disposed between the rear group GR and the image plane I. An image sensor (not shown), which is made up of a CCD, CMOS, or the like, is disposed on the image plane I.

[0146] The zoom lens ZL forms an image on an image plane I for photography. Fig. 10 shows the zoom lens ZL and the image plane I of the zoom lens ZL. Table 4 below shows the values ​​of the various specifications in the fourth embodiment.

[0147] (Table 4) Fourth Implementation Example (Basic Parameters) Wide-angle end infinity, far-angle end infinity f 8.2400 15.5200 FNo 2.9000 2.9000 ω 60.97937 40.92592 TL 123.8840 104.8072 TLa (Air Conversion Length) 123.3388 104.2620 Bf 0.1000 0.1000 Bfa (Air Conversion Length) 10.85588 19.78465 fF(G1) -16.3872 -16.3872 fR(G2-G5) 26.9879 24.5414 fR1(G2) 31.6387 fg1(L11) -17.1973 fg2(L12) -60.3456 ff(G4) 20.2316 fv(L31,32) -133.43 fvR(L33-L53) 58.8834 56.3501 LF(r1-r9) 25.8113 25.8113 LR(r11-r34) 57.0625 56.0661 Lv(r20-r34) 34.3781 34.3817 Lf(r29-r34) 11.2088 13.1455 r1 67.1470 ra(r5) 14.8937 rb(r6) -32.3370 (Men Data) Men Number rd nd νd 0 (object surface)∞ (can be changed) 1 67.1470 3.2000 1.820980 42.50 *2 11.4151 5.5366 *3 20.6567 0.4704 1.553890 38.09 4 30.0000 1.8000 1.804000 46.60 5 14.8937 8.6046 6 -32.3370 1.3000 1.593190 67.90 7 81.1140 0.1000 8 36.9819 4.7996 1.688930 31.16 9 -47.0014 d1 S10 (Aperture)∞ 1.200 11 36.9923 3.6846 1.687927 31.46 12 -16.9024 0.3700 13 -15.0981 1.3000 1.923236 35.48 14 15.9289 3.0667 1.786647 31.43 15 116.8070 0.4206 16 29.8582 5.7827 1.552000 70.70 17 -18.5589 d2 18 28.8091 3.7597 1.641308 35.66 19 -92.4375 1.3000 1.902650 35.77 20 31.1962 1.0000 21 27.7310 5.7429 1.497820 82.57 22 -12.2537 1.3000 1.902650 35.77 23 298.7898 d3 24 51.4313 5.7745 1.497820 82.57 25 -20.5154 0.1000 26 99.4540 2.3165 1.497820 82.57 27 -148.4362 0.1000 28 39.2255 2.3579 1.518600 69.89 29 128.3948 d4 30 -300.0000 4.6730 1.805180 25.45 31 -16.0848 1.3000 1.929694 34.80 32 56.7787 1.8358 *33 -531.7659 1.8000 1.851080 40.12 34 -319.6467 d5 35 0.0000 1.6000 1.516800 63.88 36 0.0000 0.1000 Image plane ∞ (Astrospherical Data) κ A4 A6 A8 A10 2 -0.4472 8.28153E-06 3.34065E-08 -3.10351E-10 -2.21139E-13 3 -4.4258 1.77446E-05 -1.22756E-07 2.49626E-11 9.92155E-14 33 1.0000 -5.30913E-05 -2.31158E-07 1.16687E-09 -1.13844E-11 (Lens Group Focal Distance) Lens Group Initial and Final Faces Group Focal Distance GF 1 9 -16.3872 (wide-angle end) -16.3872 (telephoto end) G1 1 9 -16.3872 GR 11 34 26.9879 (wide-angle end) 24.5414 (telephoto end) G2 11 17 31.6387 G3 18 23 -42.9014 G4 24 29 20.2316 G5 30 34 -38.6431 (Changeable interval data) Wide-angle end infinity Telephoto end infinity Wide-angle end to near distance Telephoto end to near distance 1-pos 2-pos 3-pos 4-pos f 8.2400 15.5200 - - Magnification - - -0.020 -0.020 d9 28.40911 1.40000 28.40911 1.40000 d17 3.00000 2.00000 3.00000 2.00000 d23 4.47755 2.54435 4.38936 2.41827 d29 1.60000 3.53676 1.68819 3.66284 d34 9.70103 18.62980 9.70103 18.62980 .

[0148] FIGS. 11 and 12 are diagrams showing various aberrations of the zoom lens ZL of Example 4 when focused on infinity at the wide-angle end and when focused on infinity at the telephoto end, respectively, and show that various aberrations are well corrected, resulting in excellent imaging performance.

[0149] 13 is a cross-sectional view of a zoom lens ZL according to Example 5. The zoom lens ZL according to this example is composed of, in order from the object side, a front group GF that has negative refractive power at least in the wide-angle end state, an aperture stop S, and a rear group GR that has positive refractive power at least in the wide-angle end state, and the front group GF and the rear group GR are separated by air gaps d9 and d10, which are the longest in the optical system in the wide-angle end state.

[0150] The front group GF is composed of, in order from the object side, a first lens group G1 having negative refractive power. Here, the first lens group G1 is composed of a negative meniscus lens L11 with a convex surface facing the object side, a negative meniscus lens L12 with a convex surface facing the object side, a biconcave negative lens L13, and a biconvex positive lens L14. The image-side surface of the negative lens L11 is aspherical, and the object-side surface of the negative lens L12 is formed with an aspherical resin layer. The focal length of the negative lens L11 closest to the object in the front group GF is fg1, and the focal length of the second negative lens L12 is fg2. The radius of curvature of the image-side surface of the third lens L12 closest to the image in the front group GF is ra, and the radius of curvature of the object-side surface of the second lens L13 is rb. The rear group GR is composed of, in order from the object side, a second lens group G2 having positive refractive power, a third lens group G3 having negative refractive power, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having positive refractive power, and a sixth lens group G6 having negative refractive power. Here, the second lens group G2 is composed of a biconvex positive lens L21, a cemented lens of a biconcave negative lens L22 and a meniscus positive lens L23 with its convex surface facing the object side, and a biconvex positive lens L24. The third lens group G3 is composed of a cemented negative lens of a biconvex positive lens L31 and a biconcave negative lens L32. The fourth lens group G4 is composed of a cemented lens of a biconvex positive lens L41 and a meniscus negative lens L42 with its concave surface facing the object side. The fifth lens group G5 is composed of a biconvex positive lens L51, a biconvex positive lens L52, and a meniscus positive lens L53 with its convex surface facing the object side. The sixth lens group G6 is composed of a cemented lens of a meniscus positive lens L61 with its concave surface facing the object side and a biconcave negative lens L62, and a meniscus positive lens L63 with its concave surface facing the object side, with the object side surface of the positive lens L63 being aspherical. The vibration-reduction lens group is composed of cemented lenses L31 and L32 in the third lens group G3, which have negative refractive power, and the object side of the vibration-reduction lens group is composed of four lenses L21 to L24. The focusing lens group is the fifth lens group G5, which has positive refractive power and moves toward the object side when focusing from infinity to a close distance. A filter group FL composed of a low-pass filter or the like is disposed between the rear group GR and the image plane I.An image pickup element (not shown) made up of a CCD, CMOS, or the like is disposed on the image plane I.

[0151] An image is formed on an image plane I by this zoom lens ZL, and photography is performed. The zoom lens ZL and the image plane I of the zoom lens ZL are shown in Figure 13. Table 5 below shows the values ​​of the various specifications in the fifth embodiment.

[0152] (Table 5) Fifth Example (Basic Specifications) Wide-angle end infinity Telephoto end infinity f 8.2399 15.5190 FNo 2.9000 2.9000 ω 61.00200 41.10760 TL 123.8837 104.4822 TLa (equivalent length in air) 123.3386 103.9371 Bf 0.1000 0.1000 Bfa (equivalent length in air) 10.85621 19.99425 fF(G1) -16.1914 -16.1914 fR(G2-G6) 26.9411 24.2495 fR1(G2) 32.4058 fg1(L11) -17.4723 fg2(L12) -57.7146 ff(G5) 20.1362 fv(L31,32) -134.6900 fvR(L41-L63) 55.8032 52.8911 LF(r1-r9) 25.7017 25.7017 LR(r11-r34) 57.3589 55.6411 Lv(r20-r34) 34.3689 33.6511 Lf(r29-r34) 10.865 12.721 r1 68.178 ra(r5) 14.7833 rb(r6) -31.8694 (Surface data) Surface number rd nd νd 0(physical surface)∞ (variable) 1 68.1780 3.2000 1.820980 42.50 *2 11.6002 5.7032 *3 20.9267 0.4704 1.553890 38.09 4 30.0000 1.8000 1.804000 46.60 5 14.7833 8.5551 6 -31.8694 1.2000 1.593190 67.90 7 79.4679 0.1000 8 35.9409 4.6730 1.688930 31.16 9 -47.8423 d9 S10 (Aperture)∞ 1.2000 11 38.3020 3.5912 1.681159 31.97 12 -16.6119 0.3308 13 -15.0583 1.2000 1.924637 35.33 14 16.4271 2.9060 1.789048 30.90 15 118.9738 0.2055 16 28.6552 6.5324 1.552000 70.70 17 -19.1917 d17 18 28.9555 4.0241 1.652146 34.53 19 -80.7698 1.2000 1.902650 35.77 20 31.1666 d20 21 28.1829 5.7852 1.497820 82.57 22 -12.0872 1.2000 1.902650 35.77 23 -19530.59100 d23 24 53.5789 5.7012 1.497820 82.57 25 -20.5519 0.1000 26 99.4524 2.2273 1.497820 82.57 27 -148.4835 0.1000 28 36.8885 2.3350 1.518600 69.89 29 120.8054 d29 30 -362.6836 4.2637 1.805180 25.45 31 -17.4729 1.2000 1.925136 35.28 32 49.9965 2.0013 *33 -345.6311 1.8000 1.851080 40.12 34 -316.6254 d34 35 0.0000 1.6000 1.516800 63.88 36 0.0000 0.1000 Image plane ∞ (Astrospherical Data) κ A4 A6 A8 A10 2 -0.4642 9.98979E-06 3.22313E-08 -3.51219E-10 -2.14883E-13 3 -4.7186 2.27033E-05 -1.39911E-07 -4.09042E-11 2.11460E-13 33 1.0000 -5.53884E-05 -2.42622E-07 1.26936E-09 -1.34661E-11 (Lens Group Focal Distance) Lens Group Initial and Final Faces Group Focal Distance GF 1 9 -16.1914 (wide-angle end) -16.1914 (telephoto end) G1 1 9 -16.1914 GR 11 34 26.9411 (wide-angle end) 24.2495 (telephoto end) G2 11 17 32.4058 G3 18 20 -134.6900 G4 21 23 -74.0734 G5 24 29 20.1362 G6 30 34 -36.3539 (changeable interval data) Wide-angle end infinity Telephoto end infinity Wide-angle end to near distance Telephoto end to near distance 1-pos 2-pos 3-pos 4-pos f 8.2399 15.519 - - Magnification - - -0.020 -0.020 d9 28.22176 1.40000 28.22176 1.40000 d17 3.00000 2.00000 3.00000 2.00000 d20 1.50000 1.00000 1.50000 1.00000 d23 4.55514 2.48142 4.46950 2.36280 d29 1.60000 3.45593 1.68565 3.57454 d34 9.70136 18.83940 9.70136 18.83940 .

[0153] FIGS. 14 and 15 are diagrams showing various aberrations of the zoom lens ZL of Example 5 when focused on infinity at the wide-angle end and when focused on infinity at the telephoto end, respectively, and show that various aberrations are well corrected, resulting in excellent imaging performance.

[0154] 16 is a cross-sectional view of a zoom lens ZL according to Example 6. The zoom lens ZL according to this example is composed of, in order from the object side, a front group GF that has negative refractive power at least in the wide-angle end state, an aperture stop S, and a rear group GR that has positive refractive power at least in the wide-angle end state, and the front group GF and the rear group GR are separated by air gaps d9 and d10, which are the longest in the optical system in the wide-angle end state.

[0155] The front group GF is composed of, in order from the object side, a first lens group G1 having negative refractive power and a second lens group G2 having positive refractive power. The first lens group G1 is composed of a negative meniscus lens L11 with a convex surface facing the object side and a negative meniscus lens L12 with a convex surface facing the object side. The second lens group G2 is composed of a biconcave negative lens L21 and a biconvex positive lens L22. The image-side surface of the negative lens L11 is aspherical, and the object-side surface of the negative lens L12 is aspherical. The focal length of the negative lens L11 closest to the object in the front group GF is fg1, and the focal length of the second negative lens L12 is fg2. The radius of curvature of the image-side surface of the third lens L12 closest to the image in the front group GF is ra, and the radius of curvature of the object-side surface of the second lens L21 is rb. The rear group GR is composed of, in order from the object side, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power. The third lens group G3 comprises a positive lens L31 having a meniscus shape with a convex surface facing the object side, a cemented lens of a negative lens L32 having a meniscus shape with a convex surface facing the object side and a positive lens L33 having a meniscus shape with a convex surface facing the object side, a biconvex positive lens L34, a cemented positive lens of a positive lens L35 having a meniscus shape with a concave surface facing the object side and a negative lens L36 having a meniscus shape with a concave surface facing the object side, a biconvex positive lens L37 and a cemented positive lens L38 having a concave surface facing the object side. The fourth lens group G4 is composed of a biconcave negative lens L41 and a meniscus positive lens L42 with a convex surface facing the object side, and the fifth lens group G5 is composed of a biconvex positive lens L51, a cemented lens of a biconvex positive lens L52 and a biconcave negative lens L53, and a meniscus negative lens L54 with a convex surface facing the object side, the negative lens L54 having an aspherical object-side surface. The vibration-proof lens group is composed of cemented lenses L35 and L36 in the third lens group G3 and has positive refractive power, and the object side of the vibration-proof lens group includes four lenses L31-L34. The focusing lens group is composed of a fourth lens group G4 and has negative refractive power, and moves toward the image side when focusing from infinity to a close distance.A filter group FL including a low-pass filter or the like is disposed between the rear group GR and the image plane I. An image sensor (not shown) including a CCD, CMOS, or the like is disposed on the image plane I.

[0156] An image is formed on an image plane I by this zoom lens ZL, and photography is performed. The zoom lens ZL and the image plane I of the zoom lens ZL are shown in Figure 16. Table 6 below shows the values ​​of the various specifications in the sixth embodiment.

[0157] (Table 6) Example 6 (Basic Parameters) Wide-angle end at infinity, far-angle end at infinity f 8.2400 15.5200 FNo 2.9000 2.9000 ω 60.49055 40.66090 TL 117.3217 96.8065 TLa (Air conversion length) 116.7765 96.2614 Bf 0.1000 0.1000 Bfa (Air conversion length) 11.86836 21.52148 fF(G1,G2) -19.0098 -18.6647 fR(G3-G5) 26.125 24.8105 fR1(G3) 19.8129 fg1(L11) -16.4609 fg2(L12) -68.4693 ff(G4) -22.8953 fv(L35,36) 166.813 fvR(L37-L54) 70.8984 70.9748 LF(r1-r9) 27.4829 26.4828 LR(r11-r33) 47.2217 45.2841 Lv(r20-r33) 31.4831 29.5455 Lf(r26-r33) 18.4062 15.9734 r1 64.5492 ra(r5) 15.4330 rb(r6) -30.8752 (Men Data) Men Number rd nd νd 0 (object surface)∞ (can be changed) 1 64.5492 3.2000 1.851080 40.12 *2 11.2488 5.8925 *3 20.4985 0.4704 1.553890 38.09 4 30.0000 1.8000 1.806100 40.98 5 15.4330 d5 6 -30.8752 1.5000 1.593190 67.90 7 238.1920 0.1000 8 43.8508 5.3199 1.688930 31.16 9 -41.4148 d9 S10 (aperture stop) ∞ 1.2000 11 41.4097 1.9517 1.688930 31.16 12 128.1364 0.1000 13 57.8633 1.5000 1.953750 32.33 14 15.4980 3.2198 1.698950 30.13 15 193.1742 0.1458 16 31.2339 2.4328 1.497820 82.57 17-3113.9948 2.0000 18 -119.8555 2.8884 1.563840 60.71 19 -19.9966 1.5000 1.902650 35.77 20 -33.3218 1.0000 21 30.6400 4.9571 1.497820 82.57 22 -14.0944 1.5000 1.883000 40.69 23 -19.9481 d23 24 -39.5295 1.5000 1.883000 40.69 25 21.2157 2.9198 1.497820 82.57 26 190.9558 d26 27 22.9027 5.9558 1.593190 67.90 28 -28.4548 0.1000 29 1799.4476 3.4200 1.593190 67.90 30 -25.0214 1.5000 1.772405 49.62 31 43.1354 1.3640 *32 100.7313 1.5000 1.851080 40.12 33 68.0025 d33 34 0.0000 1.6000 1.516800 63.88 35 0.0000 0.1000 Image plane ∞ (aspheric data) Face κ A4 A6 A8 A10 2 -0.9410 6.92799E-05 -2.78706E-07 6.87986E-10 -1.52898E-12 3 -0.6205 -2.30078E-05 -7.98768E-08 2.18456E-10 -2.85913E-13 32 1.0000 -8.13394E-05 -3.36735E-07 -3.10827E-11 -1.63913E-11 (Lens group focal distance) Lens Group Starting and Ending Planes Focal Distance GF 1 9 -19.0098 (Angle End) -18.6647 (Telescope End) G1 1 5 -11.8749 G2 6 9 86.5589 GR 11 33 26.125 (Angle End) 24.8105 (Telescope End) G3 11 23 19.8129 G4 24 26 -22.8953 G5 27 33 43.7627 (Changeable Interval Data) Angle End Infinity Telescope Infinity Angle End to Nearest Distance Telescope End to Nearest Distance 1-pos 2-pos 3-pos 4-pos f 8.2400 15.5200 - - Magnification- - -0.020 -0.020 d5 9.20004 8.20004 9.20004 8.20004 d9 29.00363 1.77297 28.92797 1.63201 d23 1.20000 1.69524 1.27566 1.83621 d26 4.56649 2.13363 4.56649 2.13363 d33 10.71351 20.36663 10.71351 20.36663 .

[0158] FIGS. 17 and 18 are diagrams showing various aberrations of the zoom lens ZL of Example 5 when focused on infinity at the wide-angle end and when focused on infinity at the telephoto end, respectively, and show that various aberrations are well corrected, providing excellent imaging performance.

[0159] 19 is a cross-sectional view of a zoom lens ZL according to Example 7. The zoom lens ZL according to this example is composed of, in order from the object side, a front group GF that has negative refractive power at least in the wide-angle end state, an aperture stop S, and a rear group GR that has positive refractive power at least in the wide-angle end state, and the front group GF and the rear group GR are separated by air gaps d9 and d10, which are the longest in the optical system in the wide-angle end state.

[0160] The front group GF is composed of, in order from the object side, a first lens group G1 having negative refractive power. Here, the first lens group G1 is composed of a negative meniscus lens L11 with a convex surface facing the object side, a negative meniscus lens L12 with a convex surface facing the object side, a negative meniscus lens L13 with a convex surface facing the object side, and a cemented lens consisting of a biconcave negative lens L14 and a biconvex positive lens L15, with the negative lens L12 having aspherical surfaces on both sides. The combined focal length of the negative lens L11 closest to the object and the second negative lens L12 in the front group GF is fg1, and the focal length of the third negative lens L13 is fg2. The radius of curvature of the image-side surface of the third lens L13 closest to the image side in the front group GF is ra, and the radius of curvature of the object-side surface of the second lens L14 is rb. The rear group GR is composed of, in order from the object side, a second lens group G2 having positive refractive power, a third lens group G3 having positive refractive power, and a fourth lens group G4 having negative refractive power. Here, the second lens group G2 is composed of a biconvex positive lens L21, a cemented lens of a biconcave negative lens L22 and a meniscus positive lens L23 with its convex surface facing the object side, a biconvex positive lens L24, a cemented negative lens of a biconvex positive lens L25 and a biconcave negative lens L26, and a cemented lens of a biconvex positive lens L27 and a meniscus negative lens L28 with its concave surface facing the object side. The third lens group G3 is composed of a biconvex positive lens L31, a biconvex positive lens L32, and a meniscus positive lens L33 with its convex surface facing the object side. The fourth lens group G4 is composed of a cemented lens of a biconvex positive lens L41 and a biconcave negative lens L42, and a meniscus positive lens L43 with its convex surface facing the object side, and the object side surface of the positive lens L43 is aspherical. The vibration-reduction lens group is made up of cemented lenses L25 and L26 in the second lens group G2, which have negative refractive power, and the object side of the vibration-reduction lens group has four lenses L21-L24. The focusing lens group is made up of third lens group G3, which has positive refractive power and moves toward the object side when focusing from infinity to a close distance. A filter group FL, such as a low-pass filter, is disposed between the rear group GR and the image plane I. An image sensor (not shown), such as a CCD or CMOS, is disposed on the image plane I.

[0161] An image is formed on an image plane I by this zoom lens ZL, and photography is performed. The zoom lens ZL and the image plane I of the zoom lens ZL are shown in Figure 19. Table 7 below shows the values ​​of each parameter in the seventh embodiment.

[0162] (Table 7) Example 7 (Basic Specifications) Wide-angle end Infinity Telephoto end Infinity f 8.2400 15.5200 FNo 2.9000 2.9000 ω 62.68504 40.75731 TL 123.8836 104.5350 TLa (air equivalent length) 123.3384 103.9899 Bf 0.1000 0.1000 Bfa (air equivalent length) 11.80967 17.32934 fF(G1) -16.7111 -16.7111 fR(G2-G4) 25.7994 23.4259 fR1(G2) 44.5436 fg1(L11,12) -19.4873 fg2(L13) -57.042 ff(G3) 23.1745 fv(L25,26) -135.365 fvR(L27-L43) 47.2981 40.1312 LF(r1-r9) 26.7911 26.7911 LR(r11-r34) 51.6521 55.4823 Lv(r20-r34) 31.4469 35.2772 Lf(r29-r34) 10.5995 14.4322 r1 64.6095 ra(r6) 16.7379 rb(r7) -36.0817 (Surface Data) Surface number r d nd νd 0 (object surface) ∞ (variable) 1 64.6095 1.5000 1.953750 32.33 2 29.7943 2.0031 *3 40.0000 1.5000 1.806040 40.74 *4 14.9306 3.1479 5 30.0000 2.2000 1.713000 53.96 6 16.7379 8.9401 7 -36.0817 1.5000 1.593190 67.90 8 28.7515 6.0000 1.688930 31.16 9 -40.8732 d9 S10 (aperture stop) ∞ 1.2000 11 25.5360 3.6845 1.688930 31.16 12 -22.5438 0.2861 13 -21.2238 1.2000 1.902650 35.77 14 13.3755 2.5786 1.737999 32.33 15 34.1616 0.1000 16 17.0516 5.3270 1.518600 69.89 17 -30.0106 2.0000 18 43.2031 3.8289 1.620041 36.26 19 -51.1105 1.2000 1.902650 35.77 20 52.8684 1.0000 21 35.2316 6.4914 1.497820 82.57 22 -10.2000 1.2000 1.902650 35.77 23 -47.2055 d23 24 785.1088 4.8185 1.497820 82.57 25 -19.2537 0.1000 26 115.1676 2.2324 1.497820 82.57 27 -123.3210 0.1000 28 24.2118 2.2577 1.518600 69.89 29 38.3681 d29 30 49.9860 4.0110 1.805180 25.45 31 -24.9238 1.2000 1.910822 35.25 32 20.8527 1.9885 33 53.4274 1.8000 1.851080 40.12 *34 68.9162 d34 35 0.0000 1.6000 1.516800 63.88 36 0.0000 0.1000 Aspherical Data (∞) Face κ A4 A6 A8 A10 3 1.9427 1.11040E-05 -5.94131E-08 -1.78765E-11 8.04297E-14 A12 A14 A16 0.34093E-15 0.10190E-18 -0.17877E-20 Face κ A4 A6 A8 A10 4 0.5707 -1.27852E-05 -1.23997E-08 -8.15268E-10 7.63906E-14 A12 A14 A16 0.44565E-14 0.22920E-16 -0.87618E-19 Face κ A4 A6 A8 A10 34 1.0000 -6.53719E-05 -3.67898E-07 1.18185E-09 -2.96241E-11 (Lens Group Focal Distance) Lens Group Initial and Final Group Focal Distance GF 1 9 -16.7111 (Angle End) -16.7111 (Telescope End) G1 1 9 -16.7111 GR 11 34 25.7994 (Angle End) 23.4259 (Telescope End) G2 11 23 44.5436 G3 24 29 23.1745 G4 30 34 -38.036 (Variable interval data) Wide-angle end Infinity Telephoto end Infinity Wide-angle end Close distance Telephoto end Close distance 1-pos 2-pos 3-pos 3-pos 4-pos f 8.2400 15.5200 - - Magnification - - -0.020 -0.020 d9 31.88562 3.18709 31.88562 3.18709 d23 2.64743 2.64501 2.55297 2.50214 d29 1.60000 5.43271 1.69446 5.57557 d34 10.65482 16.17449 10.65482 16.17449.

[0163] FIGS. 20 and 21 are diagrams showing various aberrations of the zoom lens ZL of Example 7 when focused on infinity at the wide-angle end and when focused on infinity at the telephoto end, respectively, and show that various aberrations are well corrected, resulting in excellent imaging performance.

[0164] According to each of the above embodiments, it is possible to realize a zoom lens that is compact and has good optical performance in which various aberrations are corrected from the wide-angle end state to the telephoto end state.

[0165] Next, the table of [Values ​​Corresponding to Conditional Expressions] is shown below, which summarizes the values ​​corresponding to each of the conditional expressions (1) to (20) for all the examples (Examples 1 to 7). Conditional expression (1) 1.90 < (-fFw) / fw < 4.00 Conditional expression (2) 0.50 < fg1 / fFw < 2.50 Conditional expression (3) 2.50 < fg2 / fFw < 12.00 Conditional expression (4) 10.00 < |fv| / fw < 30.00 Conditional expression (5) 0.50 < Lvw / LRw < 0.80 Conditional expression (6) 1.50 < |fv| / fvRw < 3.50 Conditional expression (7) 3.00 < |fv| / fRw < 8.00 Conditional expression (8) 3.00 < |fv| / ft < 30.00 Conditional expression (9) 0.50 < Lvt / LRt < 0.80 Conditional expression (10) 3.00 < -(fv / ff) < 10.00 Conditional expression (11) 0.20 < Lft / Lvt < 0.90 Conditional expression (12) 0.20 < (-fFw) / fR1 < 1.50 Conditional expression (13) 0.080 < (-fFw) / |fv| < 0.50 Conditional expression (14) 1.20 < LRw / LFw < 2.80 Conditional expression (15) 4.00 < r1 / fw Conditional expression (16) -1.00 < (ra+rb) / (ra-rb) < 1.00 Conditional expression (17) 0.20 < Bfaw / (-fFw) < 1.50 Conditional expression (18) 0.40 < Bfaw / fw < 3.00 Conditional expression (19) 40.00 < ωw < 80.00 Conditional expression (20) 30.00 < ωt < 55.00

[0166] [Conditional expression corresponding value] Conditional expression 1st example 2nd example 3rd example 4th example (1) 2.019 2.214 2.028 1.989 (2) 1.027(L11 / G1) 0.901(L11 / G1) 0.931(L11,12 / G1) 1.049(L11 / G1) (3) 4.047(L12 / G1) 3.668(L12 / G1) 8.879(L13 / G1) 3.682(L12 / G1) (4) 15.622(L25,26) 20.293(L25,26) 16.385(L25,26) 16.193(L31,32) (5) 0.612 0.667 0.616 0.602 (6) 2.124 2.418 2.851 2.266 (7) 4.745 6.477 5.166 4.944 (8) 8.294 10.774 8.699 8.597 (9) 0.615 0.650 0.640 0.613 (10) 0.426 7.260 5.786 6.595 (11) 0.389 0.558 0.408 0.382 (12) 0.351 0.925 0.380 0.518 (13) 0.129 0.109 0.124 0.123 (14) 2.152 1.721 1.945 2.211 (15) 8.180 7.679 8.392 8.149 (16) -0.319 -0.363 -0.293 -0.369 (17) 0.653 0.649 0.695 0.662 (18) 1.318 1.437 1.410 1.317 (19) 61.938 61.938 62.575 60.979 (20) 40.634 40.634 40.828 40.926 Conditional Expression 5th Example 6th Example 7th Example (1) 1.965 2.307 2.028 (2) 1.079(L11 / G1) 0.866(L11 / G1,2) 1.166(L11,12 / G1) (3) 3.565(L12 / G1) 3.602(L12 / G1,2) 3.413(L13 / G1) (4) 16.346(L31,32) 20.244(L35,36) 16.428(L25,26) (5) 0.599 0.667 0.609 (6) 2.414 2.353 2.862 (7) 4.999 6.385 5.247 (8) 8.679 10.748 8.722 (9) 0.605 0.652 0.636 (10) 6.689 7.286 5.841 (11) 0.370 0.541 0.409 (12) 0.500 0.959 0.375 (13) 0.120 0.114 0.123 (14) 2.232 1.718 1.928 (15) 8.274 7.834 7.841 (16) -0.366 -0.333 -0.366 (17) 0.670 0.624 0.707 (18) 1.318 1.440 1.433 (19) 61.002 60.491 62.685 (20) 41.108 40.661 40.757 However, in the values ​​corresponding to each of the above conditional formulas, (L12), (G1), etc. after the numerical value indicate the number of the lens or lens group corresponding to that value.

[0167] ZL Zoom lens GF Front group GR Rear 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 Gv Anti-vibration lens group Gf Focusing lens group S Aperture stop FL Filter group I Image plane

Claims

1. A zoom lens that is composed of, in order from the object side, a front group and a rear group, the front group and the rear group being separated by the longest air gap in the optical system in the wide-angle end state, the front group having negative refractive power at least in the wide-angle end state, the rear group having positive refractive power at least in the wide-angle end state, and is composed of a plurality of lens groups whose adjacent air gaps change during magnification, the lens group closest to the object side having positive refractive power, and that satisfies the following condition: 1.90 < (-fFw) / fw < 4.00, where fFw is the focal length of the front group relative to the d-line in the wide-angle end state, fw is the focal length of the zoom lens relative to the d-line in the wide-angle end state.

2. The zoom lens according to claim 1, wherein the front group has three or more negative lenses, at least three of the three or more negative lenses in the front group being arranged in order from the most object side, and the following condition is satisfied: 0.50 < fg1 / fFw < 2.50, where fg1 is the composite focal length for the d-line of the negative lens that is arranged in front of the second negative lens from the image side among the negative lenses arranged in order from the most object side.

3. The zoom lens according to claim 1 or 2, wherein the front group has three or more negative lenses, at least three of the three or more negative lenses in the front group are arranged in order from the most object side, and the following condition is satisfied: 2.50 < fg2 / fFw < 12.00, where fg2 is the focal length at the d-line of the second negative lens from the image side among the negative lenses arranged in order from the most object side.

4. The zoom lens according to any one of claims 1 to 3, wherein the rear group has a vibration-reduction lens group and the following conditional expressions are satisfied: 10.00 < |fv| / fw < 30.00 0.50 < Lvw / LRw < 0.80 Where, fv is the focal length of the vibration-reduction lens group for the d-line, Lvw is the distance from the lens surface of the vibration-reduction lens group closest to the image to the lens surface of the entire system closest to the image in the wide-angle end state, and LRw is the distance from the lens surface of the rear group closest to the object to the lens surface of the entire system closest to the image in the wide-angle end state.

5. A zoom lens comprising, in order from the object side, a front group and a rear group, the front group and the rear group being separated by the longest air gap within the optical system in the wide-angle end state, the front group having negative refractive power at least in the wide-angle end state, the rear group having positive refractive power at least in the wide-angle end state, the zoom lens comprising a plurality of lens groups whose air gaps between adjacent lens groups change during zooming, the lens group closest to the object side having positive refractive power, the rear group having an image stabilizing lens group, and satisfying the following conditional expressions: 10.00 < |fv| / fw < 30.00 0.50 < Lvw / LRw < 0.80 where, fv: focal length of the vibration-reduction lens group relative to the d-line fw: focal length of the zoom lens relative to the d-line in the wide-angle end state Lvw: distance from the lens surface of the vibration-reduction lens group closest to the image to the lens surface of the entire system closest to the image in the wide-angle end state LRw: distance from the lens surface of the rear group closest to the object to the lens surface of the entire system closest to the image in the wide-angle end state 6. A zoom lens according to any one of claims 1 to 5, wherein the rear group has a vibration-reduction lens group and satisfies the following conditional expressions: 1.50 < |fv| / fvRw < 3.50 0.50 < Lvw / LRw < 0.80 where, fv: focal length of the vibration-reduction lens group for the d-line fvRw: composite focal length of the lens on the image side of the vibration-reduction lens group for the d-line in the wide-angle end state Lvw: distance from the lens surface of the vibration-reduction lens group closest to the image to the lens surface closest to the image in the entire system in the wide-angle end state LRw: distance from the lens surface of the rear group closest to the object to the lens surface closest to the image in the entire system in the wide-angle end state 7. A zoom lens according to any one of claims 1 to 6, wherein the rear group has an anti-vibration lens group and satisfies the following conditional expressions: 3.00 < |fv| / fRw < 8.00 0.50 < Lvw / LRw < 0.80 Where, fv: focal length of the anti-vibration lens group for the d-line fRw: focal length of the rear group for the d-line in the wide-angle end state Lvw: distance from the lens surface of the anti-vibration lens group closest to the image to the lens surface of the entire system closest to the image in the wide-angle end state LRw: distance from the lens surface of the rear group closest to the object to the lens surface of the entire system closest to the image in the wide-angle end state 8. The zoom lens according to any one of claims 1 to 7, wherein the rear group has a vibration-reduction lens group and the following conditional expressions are satisfied: 3.00 < |fv| / ft < 30.00 0.50 < Lvt / LRt < 0.80 Where, fv: focal length of the vibration-reduction lens group for the d-line ft: focal length of the zoom lens for the d-line in the telephoto end state Lvt: distance from the lens surface of the vibration-reduction lens group closest to the image to the lens surface of the entire system closest to the image in the telephoto end state LRt: distance from the lens surface of the rear group closest to the object to the lens surface of the entire system closest to the image in the telephoto end state 9. A zoom lens according to any one of claims 1 to 8, wherein the rear group has a vibration-reduction lens group and a focusing lens group, and the following condition is satisfied: 3.00 < - (fv / ff) < 10.00, where fv is the focal length of the vibration-reduction lens group relative to the d-line, and ff is the focal length of the focusing lens group relative to the d-line.

10. A zoom lens according to any one of claims 1 to 9, wherein the rear group has an anti-vibration lens group and a focusing lens group, and the following condition is satisfied: 0.20 < Lft / Lvt < 0.90, where Lft is the distance from the lens surface of the focusing lens group closest to the image to the lens surface closest to the image in the entire system when focusing on infinity in the telephoto end state, and Lvt is the distance from the lens surface of the anti-vibration lens group closest to the image to the lens surface closest to the image in the entire system in the telephoto end state.

11. A zoom lens according to any one of claims 1 to 10, which satisfies the following condition: 0.20 < (-fFw) / fR1 < 1.50, where fFw is the focal length of the front group relative to the d-line in the wide-angle end state, and fR1 is the focal length of the lens group closest to the object side in the rear group relative to the d-line.

12. A zoom lens according to any one of claims 1 to 11, wherein the rear group has an anti-vibration lens group and satisfies the following condition: 0.080 < (-fFw) / |fv| < 0.50, where fFw is the focal length of the front group relative to the d-line in the wide-angle end state, and fv is the focal length of the anti-vibration lens group relative to the d-line.

13. A zoom lens according to any one of claims 1 to 12, wherein the rear group has a vibration-proof lens group and has three or more lenses on the object side of the vibration-proof lens group.

14. A zoom lens according to any one of claims 1 to 13, which satisfies the following condition: 1.20 < LRw / LFw < 2.80, where LRw is the distance from the lens surface of the rear group closest to the object to the lens surface closest to the image in the wide-angle end state, and LFw is the distance from the lens surface of the front group closest to the object to the lens surface closest to the image in the wide-angle end state.

15. A zoom lens according to any one of claims 1 to 14, which has an aperture stop, the rear group has an anti-vibration lens group, and the aperture stop is located closer to the object side than the anti-vibration lens group.

16. The zoom lens according to any one of claims 1 to 15, which satisfies the following condition: 4.00 < r1 / fw, where r1 is the radius of curvature of the lens surface of the zoom lens closest to the object side.

17. A zoom lens according to any one of claims 1 to 16, wherein the front group has three or more lenses, the image-side surface of the third lens from the image side and the object-side surface of the second lens from the image side have concave surfaces facing each other, and the following condition is satisfied: -1.00 < (ra + rb) / (ra - rb) < 1.00, where ra: radius of curvature of the image-side surface of the third lens from the image side in the front group, and rb: radius of curvature of the object-side surface of the second lens from the image side in the front group.

18. A zoom lens according to any one of claims 1 to 17, which satisfies the following condition: 0.20 < Bfaw / (-fFw) < 1.50, where Bfaw is the air-equivalent back focus of the zoom lens in the wide-angle end state, and fFw is the focal length of the front group relative to the d-line in the wide-angle end state.

19. The zoom lens according to any one of claims 1 to 18, which satisfies the following condition: 0.40 < Bfaw / fw < 3.00, where Bfaw is the air-equivalent back focus of the zoom lens in the wide-angle end state.

20. The zoom lens according to any one of claims 1 to 19, which satisfies the following condition: 40.00 < ωw < 80.00, where ωw is the half angle of view of the zoom lens in the wide-angle end state (unit: °).

21. A zoom lens according to any one of claims 1 to 20, which satisfies the following condition: 30.00 < ωt < 55.00, where ωt is the half angle of view of the zoom lens in the telephoto end state (unit: °).

22. An optical device comprising a zoom lens according to any one of claims 1 to 21.

23. A method for manufacturing a zoom lens comprising, in order from the object side, a front group and a rear group, the front group and the rear group being separated by the longest air gap in the optical system in the wide-angle end state, the front group having negative refractive power at least in the wide-angle end state, the rear group having positive refractive power at least in the wide-angle end state, the zoom lens being made up of a plurality of lens groups whose adjacent air gaps change during zooming, the lens group closest to the object side having positive refractive power, the method being configured to satisfy the following condition: 1.90 < (-fFw) / fw < 4.00 where, fFw: focal length of the front group relative to the d-line in the wide-angle end state fw: focal length of the zoom lens relative to the d-line in the wide-angle end state 24. A method for manufacturing a zoom lens having an image stabilizing lens group, the zoom lens comprising, in order from the object side, a front group and a rear group, the front group and the rear group being separated by the longest air gap in the optical system in the wide-angle end state, the front group having negative refractive power at least in the wide-angle end state, the rear group having positive refractive power at least in the wide-angle end state, the zoom lens comprising a plurality of lens groups whose adjacent air gaps change during zooming, the lens group closest to the object side having positive refractive power, the rear group being configured to satisfy the following conditional expression: 10.0 < |fv| / fw < 30.0 0.50 < Lvw / LRw < 0.80 where, fv: focal length of the vibration-reduction lens group at the d-line fw: focal length of the zoom lens at the wide-angle end state at the d-line Lvw: distance from the lens surface of the vibration-reduction lens group closest to the image to the lens surface of the entire system closest to the image in the wide-angle end state LRw: distance from the lens surface of the rear group closest to the object to the lens surface of the entire system closest to the image in the wide-angle end state

Images