Variable magnification optical system and optical equipment

Abstract

To provide a variable magnification optical system which is well corrected in various aberration such as spherical aberration.SOLUTION: A variable magnification optical system ZL is comprised of a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, and a succeeding lens group GR arranged in order form the object side, and is configured in such a manner that distance between each pair of adjacent lens groups changes when zooming while the first lens group G1 is stationary relative to the image plane, and the third lens group G3 moves when zooming from the wide-angle end to the telephoto end. The succeeding lens group GR consists of a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, a sixth lens group G6 having positive refractive power, and a final lens group, where the fifth lens group G5 and the sixth lens group G6 move when performing focusing. The variable magnification optical system satisfies the following conditional expressions: 0.30<f3 / (-fE)<3.50, 2.90<f1 / (-f2)<5.00.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a zoom optical system and an optical apparatus using the same.

Background Art

[0002] Conventionally, zoom optical systems suitable for photographic cameras, digital still cameras, video cameras, etc. have been proposed (see, for example, Patent Document 1). In a zoom optical system, it is required to correct aberrations well.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] The zoom optical system according to the present invention includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a subsequent lens group, which are arranged in order from the object side. During zooming, the interval between adjacent lens groups changes, the first lens group is fixed with respect to the image plane, and when zooming from the wide-angle end state to the telephoto end state, the third lens group moves. The subsequent lens group includes a fourth lens group having a positive refractive power, a fifth lens group having a negative refractive power, a sixth lens group having a positive refractive power, and a final lens group. When focusing, the fifth lens group and the sixth lens group move and satisfy the following conditional expressions. 0.30 < f3 / (-fE) < 3.50 2.90 < f1 / (-f2) < 5.00 However, f3: focal length of the third lens group fE: focal length of the final lens group f1: focal length of the first lens group f2: focal length of the second lens group

[0005] The optical device according to the third aspect is configured by mounting the above-described zoom optical system.

Brief Description of the Drawings

[0006]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Embodiments for Carrying Out the Invention

[0007] Hereinafter, the zoom optical system and the optical device according to the present embodiment will be described with reference to the drawings. First, a camera (optical device) equipped with the zoom optical system according to the present embodiment will be described based on FIG. 15. This camera 1 is a digital camera equipped with the zoom optical system according to the present embodiment as a photographing lens 2 as shown in FIG. 15. In the camera 1, light from an object (subject) (not shown) is condensed by the photographing lens 2 and reaches the imaging element 3. As a result, the light from the subject is imaged by the imaging element 3 and recorded in a memory (not shown) as a subject image. In this way, the photographer can photograph the subject with the camera 1. Note that this camera may be a mirrorless camera or a single-lens reflex type camera having a quick return mirror.

[0008] Next, the zoom optical system (imaging lens) according to the present embodiment will be described. As an example of the zoom optical system ZL (1) as the zoom optical system (zoom lens) ZL according to the present embodiment, as shown in FIG. 1, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, and a subsequent lens group GR are arranged in order from the object side. During zooming, the interval between adjacent lens groups changes. Note that during zooming, the first lens group G1 is fixed with respect to the image plane. When zooming from the wide-angle end state to the telephoto end state, the third lens group G3 moves toward the image side along the optical axis. The subsequent lens group GR has a final lens group arranged on the most image side.

[0009] Under the above configuration, the zoom optical system ZL according to the present embodiment satisfies the following conditional expression (1).

[0010] -10.00 < f3 / (-fE) < 3.50 ···(1) However, f3: Focal length of the third lens group G3 fE: Focal length of the final lens group

[0011] According to the present embodiment, it is possible to obtain a zoom optical system in which various aberrations such as spherical aberration are well corrected, and an optical device including this zoom optical system. The zoom optical system ZL according to the present embodiment may be the zoom optical system ZL (2) shown in FIG. 3, may be the zoom optical system ZL (3) shown in FIG. 5, or may be the zoom optical system ZL (4) shown in FIG. 7. Further, the zoom optical system ZL according to the present embodiment may be the zoom optical system ZL (5) shown in FIG. 9, may be the zoom optical system ZL (6) shown in FIG. 11, or may be the zoom optical system ZL (7) shown in FIG. 13.

[0012] The conditional expression (1) defines the ratio between the focal length of the third lens group G3 and the focal length of the final lens group. By satisfying the conditional expression (1), spherical aberration, coma aberration, and field curvature can be well corrected.

[0013] When the corresponding value of conditional expression (1) exceeds the upper limit value, the refractive power of the third lens group G3 becomes weak, making it difficult to correct spherical aberration and coma aberration satisfactorily. Also, since the negative refractive power of the final lens group becomes strong, it becomes difficult to correct coma aberration and field curvature satisfactorily. By setting the upper limit value of conditional expression (1) to 3.40, the effects of the present embodiment can be made more certain. In order to make the effects of the present embodiment even more certain, the upper limit value of conditional expression (1) may be set to 3.30, 3.20, 3.10, 3.00, 2.90, 2.85, 2.75, 2.70, and further to 2.65.

[0014] When the corresponding value of conditional expression (1) is below the lower limit value, the refractive power of the third lens group G3 becomes strong, making it difficult to correct spherical aberration and coma aberration satisfactorily. Also, since the refractive power of the final lens group becomes weak, it becomes difficult to correct coma aberration and field curvature satisfactorily. By setting the lower limit value of conditional expression (1) to -8.00, the effects of the present embodiment can be made more certain. In order to make the effects of the present embodiment even more certain, the lower limit value of conditional expression (1) may be set to -5.00, -3.00, -1.00, -0.50, 0.30, 0.40, and further to 0.45.

[0015] The variable magnification optical system ZL according to the present embodiment preferably satisfies the following conditional expression (2).

[0016] -10.00 < f1 / (-fE) < 3.50 ···(2) However, f1: the focal length of the first lens group G1

[0017] Conditional expression (2) defines the ratio of the focal length of the first lens group G1 to the focal length of the final lens group. By satisfying conditional expression (2), spherical aberration, field curvature, and coma aberration can be corrected satisfactorily.

[0018] When the corresponding value of conditional expression (2) exceeds the upper limit value, the refractive power of the first lens group G1 becomes weak. Therefore, it becomes difficult to satisfactorily correct the spherical aberration on the side closer to the telephoto end state and the field curvature on the side closer to the wide-angle end state. Also, since the negative refractive power of the final lens group becomes strong, it becomes difficult to satisfactorily correct the coma aberration and the field curvature. By setting the upper limit value of conditional expression (2) to 3.40, the effects of the present embodiment can be made more certain. In order to make the effects of the present embodiment even more certain, the upper limit value of conditional expression (2) may be set to 3.30, 3.20, 3.10, 3.00, 2.95, 2.90, 2.85, 2.80, and further 2.75.

[0019] When the corresponding value of conditional expression (2) is below the lower limit value, the refractive power of the first lens group G1 becomes strong. Therefore, it becomes difficult to satisfactorily correct the spherical aberration on the side closer to the telephoto end state and the field curvature on the side closer to the wide-angle end state. Also, since the refractive power of the final lens group becomes weak, it becomes difficult to satisfactorily correct the coma aberration and the field curvature. Note that by setting the lower limit value of conditional expression (2) to -8.00, the effects of the present embodiment can be made more certain. In order to make the effects of the present embodiment even more certain, the lower limit value of conditional expression (2) may be set to -5.00, -3.00, -1.00, -0.50, 0.30, 0.50, 0.75, 0.90, and further 1.00.

[0020] The variable magnification optical system ZL according to the present embodiment preferably satisfies the following conditional expression (3).

[0021] -10.00 < f2 / fE < 1.50 ···(3) However, f2: the focal length of the second lens group G2

[0022] Conditional expression (3) defines the ratio of the focal length of the second lens group G2 to the focal length of the final lens group. By satisfying conditional expression (3), the spherical aberration and the coma aberration can be satisfactorily corrected.

[0023] When the corresponding value of conditional expression (3) exceeds the upper limit value, the refractive power of the second lens group G2 becomes weak, making it difficult to satisfactorily correct spherical aberration and coma aberration. Also, since the negative refractive power of the final lens group becomes strong, it becomes difficult to satisfactorily correct coma aberration and field curvature. By setting the upper limit value of conditional expression (3) to 1.40, the effects of the present embodiment can be made more certain. In order to make the effects of the present embodiment even more certain, the upper limit value of conditional expression (3) may be set to 1.30, 1.20, 1.10, 1.00, 0.90, and further 0.80.

[0024] When the corresponding value of conditional expression (3) is below the lower limit value, the refractive power of the second lens group G2 becomes strong, making it difficult to satisfactorily correct spherical aberration and coma aberration. Also, since the refractive power of the final lens group becomes weak, it becomes difficult to satisfactorily correct coma aberration and field curvature. By setting the lower limit value of conditional expression (3) to -8.00, the effects of the present embodiment can be made more certain. In order to make the effects of the present embodiment even more certain, the lower limit value of conditional expression (3) may be set to -5.00, -3.00, -1.00, -0.50, 0.10, 0.20, 0.30, and further 0.35.

[0025] The variable magnification optical system ZL according to the present embodiment preferably satisfies the following conditional expression (4).

[0026] 1.50 < f1 / (-f2) < 5.00 ···(4) However, f1: focal length of the first lens group G1 f2: focal length of the second lens group G2

[0027] Conditional expression (4) defines the ratio of the focal length of the first lens group G1 to the focal length of the second lens group G2. By satisfying conditional expression (4), coma aberration and spherical aberration can be satisfactorily corrected, and a variable magnification ratio that satisfies the present embodiment can be ensured.

[0028] When the corresponding value of conditional expression (4) exceeds the upper limit value, the refractive power of the second lens group G2 becomes strong, making it difficult to correct coma aberration and spherical aberration. By setting the upper limit value of conditional expression (4) to 4.80, the effects of the present embodiment can be made more certain. To make the effects of the present embodiment even more certain, the upper limit value of conditional expression (4) may be set to 4.50, 4.30, 4.00, 3.90, 3.80, and further 3.75.

[0029] When the corresponding value of conditional expression (4) is below the lower limit value, the refractive power of the first lens group G1 becomes strong, making it difficult to correct coma aberration and spherical aberration. By setting the lower limit value of conditional expression (4) to 1.75, the effects of the present embodiment can be made more certain. To make the effects of the present embodiment even more certain, the lower limit value of conditional expression (4) may be set to 1.90, 2.00, 2.25, 2.40, 2.50, 2.70, 2.80, 2.90, and further 3.00.

[0030] The variable magnification optical system ZL according to the present embodiment preferably satisfies the following conditional expression (5).

[0031] 0.80 < f1 / f3 < 2.50 ···(5) However, f1: the focal length of the first lens group G1

[0032] Conditional expression (5) defines the ratio of the focal length of the first lens group G1 to the focal length of the third lens group G3. By satisfying conditional expression (5), spherical aberration and coma aberration can be corrected well.

[0033] When the corresponding value of conditional expression (5) exceeds the upper limit value, the refractive power of the third lens group G3 becomes strong, making it difficult to correct spherical aberration and coma aberration. By setting the upper limit value of conditional expression (5) to 2.45, the effects of the present embodiment can be made more certain. To make the effects of the present embodiment even more certain, the upper limit value of conditional expression (5) may be set to 2.40, 2.20, 2.00, 1.90, 1.80, 1.70, 1.60, and further 1.50.

[0034] When the corresponding value of conditional expression (5) is less than the lower limit value, the refractive power of the first lens group G1 becomes strong, making it difficult to correct spherical aberration and coma aberration. By setting the lower limit value of conditional expression (5) to 0.82, the effects of the present embodiment can be made more certain. In order to make the effects of the present embodiment even more certain, the lower limit value of conditional expression (5) may be set to 0.85, 0.87, 0.90, 0.92, 0.95, 0.98, and further 1.00.

[0035] In the variable magnification optical system ZL according to the present embodiment, the subsequent lens group GR has a fourth lens group G4, and it is desirable to satisfy the following conditional expression (6).

[0036] -2.00 < f1 / f4 < 4.00 ···(6) However, f1: focal length of the first lens group G1 f4: focal length of the fourth lens group G4

[0037] Conditional expression (6) defines the ratio of the focal length of the first lens group G1 to the focal length of the fourth lens group G4. By satisfying conditional expression (6), spherical aberration and coma aberration can be corrected well.

[0038] When the corresponding value of conditional expression (6) exceeds the upper limit value, the refractive power of the fourth lens group G4 becomes strong, making it difficult to correct spherical aberration and coma aberration. By setting the upper limit value of conditional expression (6) to 3.80, the effects of the present embodiment can be made more certain. In order to make the effects of the present embodiment even more certain, the upper limit value of conditional expression (6) may be set to 3.60, 3.50, 3.20, 3.00, 2.80, 2.60, 2.50, 2.40, and further 2.30.

[0039] When the corresponding value of conditional expression (6) is lower than the lower limit value, the refractive power of the first lens group G1 increases, making it difficult to correct spherical aberration and coma aberration. By setting the lower limit value of conditional expression (6) to -1.50, the effects of the present embodiment can be made more certain. In order to make the effects of the present embodiment even more certain, the lower limit value of conditional expression (6) may be set to 0.50, 0.80, 1.00, 1.20, 1.40, 1.50, and further 1.55.

[0040] In the zoom optical system ZL according to the present embodiment, it is desirable that the final lens group be fixed with respect to the image plane during zooming. Thereby, the drive mechanism of the lens group of the present embodiment can be simplified and the lens barrel can be miniaturized.

[0041] In the zoom optical system ZL according to the present embodiment, it is desirable that at least one lens group among the lens groups arranged on the image side of the third lens group G3 be fixed with respect to the image plane during zooming. Thereby, the drive mechanism of the lens group of the present embodiment can be simplified, the lens barrel can be miniaturized, and the aberration variation during zooming can be reduced, which is preferable.

[0042] In the zoom optical system ZL according to the present embodiment, the subsequent lens group GR has, in order from the object side, a first focusing lens group having a negative refractive power that moves during focusing and a second focusing lens group having a positive refractive power that moves during focusing, and it is desirable to satisfy the following conditional expression (7).

[0043] 0.80 < (-fF1) / fF2 < 5.00 ···(7) However, fF1: focal length of the first focusing lens group fF2: focal length of the second focusing lens group

[0044] Conditional expression (7) defines the ratio of the focal length of the first focusing lens group to the focal length of the second focusing lens group. By satisfying conditional expression (7), variations in various aberrations such as spherical aberration during focusing from an infinite object to a close object can be suppressed.

[0045] When the corresponding value of conditional expression (7) exceeds the upper limit value, the refractive power of the second focusing lens group becomes stronger, making it difficult to suppress fluctuations in various aberrations such as spherical aberration during focusing. By setting the upper limit value of conditional expression (7) to 4.75, the effects of this embodiment can be made more certain. To make the effects of this embodiment even more certain, the upper limit value of conditional expression (7) may be set to 4.50, 4.25, 4.00, 3.75, 3.50, 3.25, 3.00, 2.75, 2.50, 2.25, and further 2.00.

[0046] When the corresponding value of conditional expression (7) is below the lower limit value, the negative refractive power of the first focusing lens group becomes stronger, making it difficult to suppress fluctuations in various aberrations such as spherical aberration during focusing. By setting the lower limit value of conditional expression (7) to 0.85, the effects of this embodiment can be made more certain. To make the effects of this embodiment even more certain, the lower limit value of conditional expression (7) may be set to 0.90, 1.00, 1.10, 1.20, 1.25, 1.28, and further 1.30.

[0047] In the variable magnification optical system ZL according to this embodiment, it is desirable that the second lens group G2 has a positive lens that satisfies the following conditional expressions (8) to (10).

[0048] 18.0 < νdP < 35.0 ···(8) 1.83 < ndP+(0.01425×νdP) < 2.12 ···(9) 0.702 < θgFP+(0.00316×νdP) ···(10) However, νdP: Abbe number based on the d-line of the positive lens ndP: Refractive index with respect to the d-line of the positive lens θgFP is the partial dispersion ratio of the positive lens. When the refractive index with respect to the g-line of the positive lens is ngP, the refractive index with respect to the F-line of the positive lens is nFP, and the refractive index with respect to the C-line of the positive lens is nCP, it is defined by the following formula θgFP=(ngP - nFP) / (nFP - nCP) Note that the Abbe number νdP based on the d-line of the positive lens is defined by the following formula νdP = (ndP - 1) / (nFP - nCP)

[0049] Conditional expression (8) defines an appropriate range of the Abbe number based on the d-line of the positive lens in the second lens group G2. By satisfying conditional expression (8), it is possible to satisfactorily correct reference aberrations such as spherical aberration and coma aberration, and to correct primary chromatic aberration (achromatism).

[0050] When the corresponding value of conditional expression (8) exceeds the upper limit value, it becomes difficult to correct axial chromatic aberration, which is not preferable. By setting the upper limit value of conditional expression (8) to 32.5, the effects of the present embodiment can be made more certain. In order to make the effects of the present embodiment even more certain, it is preferable to set the upper limit value of conditional expression (8) to 31.5.

[0051] When the corresponding value of conditional expression (8) is below the lower limit value, it becomes difficult to correct axial chromatic aberration, which is not preferable. By setting the lower limit value of conditional expression (8) to 20.00, the effects of the present embodiment can be made more certain. In order to make the effects of the present embodiment even more certain, it is preferable to set the lower limit value of conditional expression (8) to 22.00, 23.00, 23.50, 24.00, 25.00, and further 26.00.

[0052] Conditional expression (9) defines an appropriate relationship between the refractive index with respect to the d-line of the positive lens in the second lens group G2 and the Abbe number based on the d-line. By satisfying conditional expression (9), it is possible to satisfactorily correct reference aberrations such as spherical aberration and coma aberration, and to correct primary chromatic aberration (achromatism).

[0053] If the corresponding value of conditional expression (9) is outside the above range, for example, the Petzval sum becomes small, making it difficult to correct field curvature, which is not preferable. By setting the upper limit value of conditional expression (9) to 2.10, the effects of the present embodiment can be made more certain. In order to make the effects of the present embodiment even more certain, it is preferable to set the upper limit value of conditional expression (9) to 2.08, and further to 2.06. Also, by setting the lower limit value of conditional expression (9) to 1.84, the effects of the present embodiment can be made more certain. In order to make the effects of the present embodiment even more certain, it is preferable to set the lower limit value of conditional expression (9) to 1.85.

[0054] Conditional expression (10) appropriately defines the abnormal dispersibility of the positive lens in the second lens group G2. By satisfying conditional expression (10), in the correction of chromatic aberration, in addition to primary color cancellation, secondary spectrum can be corrected well.

[0055] When the corresponding value of conditional expression (10) is below the lower limit value, the abnormal dispersibility of the positive lens becomes small, making it difficult to correct chromatic aberration. By setting the lower limit value of conditional expression (10) to 0.704, the effects of the present embodiment can be made more certain. In order to make the effects of the present embodiment even more certain, it is preferable to set the lower limit value of conditional expression (10) to 0.708, 0.710, and further to 0.715.

[0056] The zoom optical system ZL according to the present embodiment preferably satisfies the following conditional expression (11).

[0057] 25.00° < 2ωw < 50.00° ···(11) However, 2ωw: the total angle of view of the zoom optical system ZL in the wide-angle end state

[0058] The conditional expression (11) defines the overall angle of view of the zoom optical system ZL in the wide-angle end state. By satisfying the conditional expression (11), while having a wide angle of view that satisfies this embodiment, various aberrations such as coma aberration, distortion aberration, and field curvature can be corrected well. By setting the lower limit value of the conditional expression (11) to 27.00°, the effects of this embodiment can be made more certain. In order to make the effects of this embodiment even more certain, the lower limit value of the conditional expression (11) may be set to 29.00°, 30.00°, 32.00°, and further 33.00°. Also, by setting the upper limit value of the conditional expression (11) to 48.00°, the effects of this embodiment can be made more certain. In order to make the effects of this embodiment even more certain, the upper limit value of the conditional expression (11) may be set to 45.00°, 42.00°, 40.00°, 38.00°, 36.00°, and further 35.00°.

[0059] The zoom optical system ZL according to this embodiment preferably satisfies the following conditional expression (12).

[0060] 5.00° < 2ωt < 20.00° ···(12) However, 2ωt: The overall angle of view of the zoom optical system ZL in the telephoto end state

[0061] The conditional expression (12) defines the overall angle of view of the zoom optical system ZL in the telephoto end state. By satisfying the conditional expression (12), various aberrations such as coma aberration, distortion aberration, and field curvature can be corrected well. By setting the upper limit value of the conditional expression (12) to 18.00°, the effects of this embodiment can be made more certain. In order to make the effects of this embodiment even more certain, the upper limit value of the conditional expression (12) may be set to 16.00°, 15.00°, 14.00°, and further 13.00°. On the other hand, by setting the lower limit value of the conditional expression (12) to 7.00°, the effects of this embodiment can be made more certain. In order to make the effects of this embodiment even more certain, the lower limit value of the conditional expression (12) may be set to 8.00°, 10.00°, 11.00°, and further 12.00°.

[0062] The zoom optical system ZL according to this embodiment preferably satisfies the following conditional expression (13).

[0063] 0.20 < BFw / fw < 0.85 ···(13) Here, BFw: Back focus of the zoom optical system ZL in the wide-angle end state fw: Focal length of the zoom optical system ZL in the wide-angle end state

[0064] The conditional expression (13) defines the ratio of the back focus of the zoom optical system ZL in the wide-angle end state to the focal length of the zoom optical system ZL in the wide-angle end state. By satisfying the conditional expression (13), various aberrations including coma aberration in the wide-angle end state can be corrected well.

[0065] When the corresponding value of the conditional expression (13) exceeds the upper limit value, the back focus becomes too large with respect to the focal length of the zoom optical system ZL in the wide-angle end state, so it becomes difficult to correct various aberrations including coma aberration in the wide-angle end state. By setting the upper limit value of the conditional expression (13) to 0.80, the effect of this embodiment can be made more certain. In order to make the effect of this embodiment more certain, the upper limit value of the conditional expression (13) may be set to 0.75, 0.70, 0.65, 0.60, and further 0.55.

[0066] When the corresponding value of the conditional expression (13) is below the lower limit value, the back focus becomes too small with respect to the focal length of the zoom optical system ZL in the wide-angle end state, so it becomes difficult to correct various aberrations including coma aberration in the wide-angle end state. Also, it becomes difficult to arrange the mechanical members of the lens barrel. By setting the lower limit value of the conditional expression (13) to 0.25, the effect of this embodiment can be made more certain. In order to make the effect of this embodiment more certain, the lower limit value of the conditional expression (13) may be set to 0.30, 0.35, 0.40, and further 0.42.

[0067] Next, with reference to FIG. 16, the manufacturing method of the zoom optical system ZL according to this embodiment will be outlined. First, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, and a subsequent lens group GR are arranged (step ST1). Then, during zooming, the intervals between adjacent lens groups are configured to change (step ST2). During zooming, the first lens group G1 is fixed with respect to the image plane. When zooming from the wide-angle end state to the telephoto end state, the third lens group G3 moves toward the image side along the optical axis. Also, a final lens group is arranged on the most image side of the subsequent lens group GR (step ST3). Further, each lens is arranged in the lens barrel so as to satisfy at least the above conditional expression (1) (step ST4). According to such a manufacturing method, it becomes possible to manufacture a zoom optical system in which various aberrations such as spherical aberration are well corrected.

Example

[0068] Hereinafter, the zoom optical system ZL according to the example of this embodiment will be described with reference to the drawings. FIGS. 1, 3, 5, 7, 9, 11, and 13 are diagrams showing the movement of the lenses when the zoom optical systems ZL {ZL(1) to ZL(7)} according to the first to seventh examples change from the wide-angle end state to the telephoto end state. In each figure, the moving direction along the optical axis of the lens group that moves during zooming from the wide-angle end state to the telephoto end state is indicated by an arrow. Further, the moving direction when the focusing lens group focuses from infinity to a near-distance object is indicated by an arrow together with the word "focusing".

[0069] In these figures (FIGS. 1, 3, 5, 7, 9, 11, 13), each lens group is represented by a combination of the symbol G and a number, and each lens is represented by a combination of the symbol L and a number. In this case, in order to prevent the types and numbers of the symbols and numbers from becoming large and complicated, the lens groups and the like are represented by independent combinations of symbols and numbers for each example. Therefore, even if the same combination of symbol and number is used between examples, it does not mean that they have the same configuration.

[0070] Tables 1 to 7 are shown below. Among these, Table 1 shows the specifications data in the first embodiment, Table 2 shows the second embodiment, Table 3 shows the third embodiment, Table 4 shows the fourth embodiment, Table 5 shows the fifth embodiment, Table 6 shows the sixth embodiment, and Table 7 shows the seventh embodiment. In each embodiment, the d-line (wavelength λ = 587.6 nm) and the g-line (wavelength λ = 435.8 nm) are selected as the objects for calculating the aberration characteristics.

[0071] In the table of [Overall Specifications], FNO is the F-number, 2ω is the angle of view (the unit is ° (degrees), where ω is the semi-angle of view), and Y is the image height. TL indicates the distance obtained by adding BF to the distance from the frontmost surface of the lens to the final surface of the lens on the optical axis when focused at infinity. BF indicates the air-equivalent distance (back focus) from the final surface of the lens to the image plane I on the optical axis when focused at infinity. Note that these values are shown for each of the zoom states of the wide-angle end (W), the intermediate focal length (M), and the telephoto end (T). Also, in the table of [Overall Specifications], θgFP indicates the partial dispersion ratio of the positive lens portion in the second lens group.

[0072] In the table of [Lens Specifications], the surface number indicates the order of the optical surfaces from the object side along the direction of light propagation. R is the radius of curvature of each optical surface (a surface with the center of curvature located on the image side is taken as a positive value), D is the surface interval, which is the distance on the optical axis from each optical surface to the next optical surface (or the image plane), nd is the refractive index of the material of the optical member with respect to the d-line, νd is the Abbe number based on the d-line of the material of the optical member, and θgF indicates the partial dispersion ratio of the material of the optical member, respectively. "∞" for the radius of curvature indicates a plane or an aperture, and (stop S) indicates the aperture stop. The description of the refractive index of air nd = 1.00000 is omitted. When the lens surface is an aspherical surface, an asterisk is attached to the surface number, and the paraxial radius of curvature is shown in the column of the radius of curvature R.

[0073] Let ng be the refractive index of the material of the optical member with respect to the g-line (wavelength λ = 435.8 nm), nF be the refractive index of the material of the optical member with respect to the F-line (wavelength λ = 486.1 nm), and nC be the refractive index of the material of the optical member with respect to the C-line (wavelength λ = 656.3 nm). At this time, the partial dispersion ratio θgF of the material of the optical member is defined by the following formula (A).

[0074] θgF = (ng - nF) / (nF - nC) …(A)

[0075] In the table of [Aspherical Data], for the aspherical surface shown in [Lens Specifications], its shape is expressed by the following formula (B). X(y) represents the distance (sag amount) along the optical axis from the tangent plane at the vertex of the aspherical surface to the position on the aspherical surface at height y, R represents the radius of curvature of the reference sphere (paraxial radius of curvature), κ represents the conic constant, and Ai represents the i-th order aspherical coefficient. "E-n" represents "×10 -n ". For example, 1.234E-05 = 1.234×10 -5 . Note that the second-order aspherical coefficient A2 is 0, and its description is omitted.

[0076] X(y) = (y 2 / 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 ···(B)

[0077] In the table of [Lens Group Data], the starting surface (the surface closest to the object side) and the focal length of each lens group are shown.

[0078] In the table of [Variable Interval Data], the interval between the surfaces with the surface numbers where the interval between the surfaces is "variable" in the table showing [Lens Specifications] is shown. Here, for each of the cases when focused at infinity and at close range, the intervals between the surfaces in each zoom state of the wide-angle end (W), the intermediate focal length (M), and the telephoto end (T) are shown. In [Variable Interval Data], f represents the focal length of the entire lens system, and β represents the shooting magnification.

[0079] In the table of [Condition Formula Corresponding Values], the values corresponding to each condition formula are shown.

[0080] Hereinafter, for all specification values, the focal length f, radius of curvature R, surface interval D, and other lengths that are published are generally "mm" when not otherwise specified. However, since the same optical performance can be obtained even if the optical system is proportionally enlarged or reduced, it is not limited to this.

[0081] The explanations of the tables so far are common to all examples, and the overlapping explanations below will be omitted.

[0082] (First Embodiment) The first embodiment will be described with reference to FIGS. 1 to 2 and Table 1. FIG. 1 is a diagram showing the movement of the lenses when the zoom optical system according to the first embodiment changes from the wide-angle end state to the telephoto end state. The zoom optical system ZL(1) according to the first embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, a sixth lens group G6 having a positive refractive power, a seventh lens group G7 having a negative refractive power, an eighth lens group G8 having a positive refractive power, and a ninth lens group G9 having a negative refractive power. When zooming from the wide-angle end state to the telephoto end state, the second lens group G2, the third lens group G3, the fifth lens group G5, the seventh lens group G7, and the eighth lens group G8 move separately in the directions indicated by the arrows in FIG. 1, and the intervals between adjacent lens groups change. Note that when zooming, the first lens group G1, the fourth lens group G4, the sixth lens group G6, and the ninth lens group G9 are fixed with respect to the image plane I. The lens group composed of the fourth lens group G4, the fifth lens group G5, the sixth lens group G6, the seventh lens group G7, the eighth lens group G8, and the ninth lens group G9 corresponds to the subsequent lens group GR. The signs (+) or (-) attached to each lens group symbol indicate the refractive power of each lens group, and this is the same for all the following embodiments.

[0083] The first lens group G1 is composed of, in order from the object side, a cemented lens of a negative meniscus lens L11 with a convex surface facing the object side and a plano-convex positive lens L12 with a convex surface facing the object side, and a positive meniscus lens L13 with a convex surface facing the object side.

[0084] The second lens group G2 is composed of, arranged in order from the object side, a negative meniscus lens L21 with a convex surface facing the object side, a negative lens L22 with a biconcave shape, a positive meniscus lens L23 with a convex surface facing the object side, and a negative lens L24 with a biconcave shape.

[0085] The third lens group G3 is composed of a positive meniscus lens L31 with a convex surface facing the object side.

[0086] The fourth lens group G4 is composed of, arranged in order from the object side, a positive lens L41 with a biconvex shape and a negative meniscus lens L42 with a convex surface facing the object side.

[0087] The fifth lens group G5 is composed of a cemented lens of a negative lens L51 with a biconcave shape and a positive lens L52 with a biconvex shape. An aperture stop S is disposed on the most object side of the fifth lens group G5 and moves together with the fifth lens group G5 during zooming.

[0088] The sixth lens group G6 is composed of, arranged in order from the object side, a negative meniscus lens L61 with a convex surface facing the object side, a cemented lens of a positive lens L62 with a biconvex shape and a negative meniscus lens L63 with a concave surface facing the object side, and a positive meniscus lens L64 with a convex surface facing the object side. The positive lens L62 has an aspherical lens surface on the object side.

[0089] The seventh lens group G7 is composed of, arranged in order from the object side, a positive meniscus lens L71 with a concave surface facing the object side and a negative meniscus lens L72 with a convex surface facing the object side.

[0090] The eighth lens group G8 is composed of a positive lens L81 with a biconvex shape.

[0091] The ninth lens group G9 is composed of a negative meniscus lens L91 with a concave surface facing the object side and a negative meniscus lens L92 with a concave surface facing the object side, arranged in order from the object side. The negative meniscus lens L91 has an aspherical lens surface on the object side. An image plane I is disposed on the image side of the ninth lens group G9. That is, the ninth lens group G9 corresponds to the final lens group.

[0092] In this embodiment, by moving the seventh lens group G7 toward the image plane I side and moving the eighth lens group G8 toward the object side, focusing is performed from a distant object to a near object (from an infinite object to a finite distance object). That is, the seventh lens group G7 corresponds to the first focusing lens group, and the eighth lens group G8 corresponds to the second focusing lens group.

[0093] The following Table 1 lists the values of the specifications of the zoom optical system according to the first embodiment.

[0094] (Table 1) [Overall specifications] Zoom ratio 2.74 θgFP = 0.6319 W M T FNO 2.88277 2.8637 2.87906 2ω 33.79332 17.81742 12.27158 Y 21.70 21.70 21.70 TL 199.88619 199.88619 199.88619 BF 32.5469 32.5469 32.5469 [Lens specifications] Surface number R D nd νd θgF 1 116.34563 2.80 2.00100 29.12 2 85.133 9.70 1.49782 82.57 3 ∞ 0.10 4 92.01324 7.70 1.43385 95.25 5 696.98757 D5 (variable) 6 58.77 1.90 1.60300 65.44 7 31.87745 10.30 8 -186.53352 1.60 1.49782 82.57 9 105.34866 0.80 10 41.08366 3.70 1.66382 27.35 0.6319 11 64.00891 5.50 12 -71.62319 1.90 1.49782 82.57 13 88.67881 D13 (variable) 14 69.46271 3.20 1.94595 17.98 15 201.8299 D15 (variable) 16 126.26563 4.70 1.49782 82.57 17 -126.26563 0.10 18 47.66354 3.85 1.49782 82.57 19 122.86616 D19 (variable) 20 ∞ 3.50 (Aperture S) 21 -84.82141 1.80 1.92286 20.88 22 52.171 5.00 1.49782 82.57 23 -170.93248 D23 (variable) 24 111.64091 1.70 1.85026 32.35 25 60.55636 2.00 26* 58.68256 7.70 1.59306 66.97 27 -55.839 1.70 1.62004 36.4 28 -95.85894 1.30 29 58.0393 2.70 1.80100 34.92 30 135.30037 D30 (variable) 31 -369.28597 2.00 1.94595 17.98 32 -98.65201 0.80 33 1344.92022 1.25 1.71300 53.96 34 37.13115 D34 (Variable) 35 119.39985 3.85 1.90265 35.77 36 -119.39985 D36 (Variable) 37* -83.23047 1.90 1.51696 64.14 38 -335.27926 4.10 39 -54.71091 1.90 1.56384 60.71 40 -276.64763 BF [Aspherical Data] The 26th surface κ = 0.00, A4 = -2.00E-06, A6 = 8.31E-10 A8 = -6.83E-12, A10 = 2.63E-14, A12 = -3.55E-17 The 37th surface κ = 0.00, A4 = 1.18E-06, A6 = 1.63E-09 A8 = -7.32E-12, A10 = 2.41E-14, A12 = -2.65E-17 [Lens Group Data] Group Start Surface Focal Length G1 1 147.97696 G2 6 -40.5909 G3 14 110.66613 G4 16 69.76371 G5 20 -62.56946 G6 24 56.88582 G7 31 -87.28124 G8 35 66.64828 G9 37 -76.28082 [Variable Interval Data] W M T W M T Infinity Infinity Infinity Close Distance Close Distance Close Distance f 71.50119 135 196 ― ― ― β ― ― ― -0.08318 -0.14416 -0.19832 D5 1.59716 33.49859 49.53103 1.59716 33.49859 49.53103 D13 37.80333 11.65214 1.60516 37.80333 11.65214 1.60516 D15 14.09965 8.34942 2.36395 14.09965 8.34942 2.36395 D19 4.24982 7.0795 8.12305 4.24982 7.0795 8.12305 D23 5.35666 2.52698 1.48342 5.35666 2.52698 1.48342 D30 3.81632 6.22894 4.10722 5.10137 11.89468 15.63265 D34 28.12371 22.59291 27.70989 24.58984 10.97816 4.65903 D36 3.7896 6.90778 3.91252 6.03843 12.8568 15.43795 [Conditional corresponding value] Conditional expression (1) f3 / (-fE)=1.45 Conditional expression (2) f1 / (-fE)=1.94 Conditional expression (3) f2 / fE=0.53 Conditional expression (4) f1 / (-f2)=3.65 Conditional expression (5) f1 / f3=1.34 Conditional expression (6) f1 / f4=2.12 Conditional expression (7) (-fF1) / fF2=1.31 Conditional expression (8) νdP=27.35 Conditional expression (9) ndP+(0.01425×νdP)=2.0536 Conditional expression (10) θgFP+(0.00316×νdP)=0.7183 Conditional expression (11) 2ωw=33.79° Conditional expression (12) 2ωt=12.27° Conditional expression (13) BFw / fw=0.46

[0095] FIG. 2(A), FIG. 2(B), and FIG. 2(C) are aberration diagrams in the wide-angle end state, intermediate focal length state, and telephoto end state of the zoom optical system according to the first embodiment, respectively. In each aberration diagram, FNO indicates the F-number, and Y indicates the image height. In the spherical aberration diagram, the value of the F-number corresponding to the maximum aperture is shown. In the astigmatism diagram and the distortion aberration diagram, the maximum value of the image height is shown, respectively. In the lateral aberration diagram, the value of each image height is shown. d indicates the d-line (wavelength λ = 587.6 nm), and g indicates the g-line (wavelength λ = 435.8 nm). In the astigmatism diagram, the solid line indicates the sagittal image plane, and the dashed line indicates the meridional image plane. Note that, in the aberration diagrams of each of the following embodiments, the same reference numerals as those in this embodiment are used, and duplicate descriptions are omitted.

[0096] From each of the aberration diagrams, it can be seen that the zoom optical system according to the first embodiment has good correction of various aberrations and excellent imaging performance.

[0097] (Second Embodiment) The second embodiment will be described with reference to FIGS. 3 to 4 and Table 2. FIG. 3 is a diagram showing the movement of the lens when the zoom optical system according to the second embodiment changes from the wide-angle end state to the telephoto end state. The zoom optical system ZL(2) according to the second embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, a sixth lens group G6 having a positive refractive power, and a seventh lens group G7 having a negative refractive power. When zooming from the wide-angle end state to the telephoto end state, the second lens group G2, the third lens group G3, the fifth lens group G5, and the sixth lens group G6 move separately in the directions indicated by the arrows in FIG. 3, and the intervals between adjacent lens groups change. Note that, during zooming, the first lens group G1, the fourth lens group G4, and the seventh lens group G7 are fixed with respect to the image plane I. The lens group composed of the fourth lens group G4, the fifth lens group G5, the sixth lens group G6, and the seventh lens group G7 corresponds to the subsequent lens group GR.

[0098] The first lens group G1 is composed of a cemented lens including a negative meniscus lens L11 with a convex surface facing the object side, a positive lens L12 with a biconvex shape, and a positive meniscus lens L13 with a convex surface facing the object side, arranged in order from the object side.

[0099] The second lens group G2 is composed of a negative meniscus lens L21 with a convex surface facing the object side, a negative lens L22 with a biconcave shape, a positive meniscus lens L23 with a convex surface facing the object side, and a negative meniscus lens L24 with a concave surface facing the object side, arranged in order from the object side.

[0100] The third lens group G3 is composed of a positive meniscus lens L31 with a convex surface facing the object side.

[0101] The fourth lens group G4 is composed of a positive meniscus lens L41 with a convex surface facing the object side, a positive meniscus lens L42 with a convex surface facing the object side, a cemented lens including a negative lens L43 with a biconcave shape and a positive lens L44 with a biconvex shape, a negative meniscus lens L45 with a convex surface facing the object side, a cemented lens including a positive lens L46 with a biconvex shape and a negative meniscus lens L47 with a concave surface facing the object side, and a positive meniscus lens L48 with a convex surface facing the object side, arranged in order from the object side. An aperture stop S is disposed between the positive meniscus lens L42 and the negative lens L43 in the fourth lens group G4 and moves together with the fourth lens group G4 during zooming. The positive lens L46 has an aspherical surface on the lens surface on the object side.

[0102] The fifth lens group G5 is composed of a positive meniscus lens L51 with a concave surface facing the object side and a negative lens L52 with a biconcave shape, arranged in order from the object side.

[0103] The sixth lens group G6 is composed of a positive lens L61 with a biconvex shape.

[0104] The seventh lens group G7 is composed of a negative lens L71 with a biconcave shape. The negative lens L71 has an aspherical surface on the lens surface on the object side. An image plane I is disposed on the image side of the seventh lens group G7. That is, the seventh lens group G7 corresponds to the final lens group.

[0105] In this embodiment, by moving the fifth lens group G5 toward the image plane I side and moving the sixth lens group G6 toward the object side, focusing is performed from a long-distance object to a short-distance object (from an infinite object to a finite-distance object). That is, the fifth lens group G5 corresponds to the first focusing lens group, and the sixth lens group G6 corresponds to the second focusing lens group.

[0106] The following Table 2 lists the values of the specifications of the zoom optical system according to the second embodiment.

[0107] (Table 2) [Overall specifications] Zoom ratio 2.74 θgFP = 0.6319 W M T FNO 2.87938 2.83556 2.81768 2ω 33.81302 17.80714 12.26884 Y 21.70 21.70 21.70 TL 196.12284 196.12284 196.12284 BF 36.61267 36.61267 36.61267 [Lens specifications] Surface number R D nd νd θgF 1 108.74314 2.8 1.95000 31.13 2 80.29769 9.7 1.49782 82.57 3 -691.77549 0.1 4 93.78423 7.7 1.43385 95.23 5 338.64045 D5 (variable) 6 71.48912 1.9 1.59349 67.89 7 30.17301 9.4 8 -137.03151 1.6 1.49782 82.57 9 93.66474 0.8 10 44.41047 3.94815 1.66382 27.35 0.6319 11 87.61105 5.59008 12 -54.89519 1.9 1.49782 82.57 13 -689.02421 D13 (variable) 14 75.42635 4.5 1.94595 30.42 15 490.04562 D15 (variable) 16 94.04866 4 1.49782 59.34 17 1181.8169 0.1 18 56.70631 4 1.49782 69.79 19 243.15543 4.5 20 ∞ 3.5 (aperture S) 21 -180.79776 1.8 1.92286 29.82 22 38.61345 4.2 1.49782 67.44 23 -792.77195 4.35979 24 479.73489 1.7 1.80518 22.51 25 75.80342 2 26* 58.49695 7.7 1.59306 67 27 -63.34766 1.7 1.60342 46.96 28 -90.09789 1.3 29 66.31481 2.5 1.80400 44.63 30 153.3585 D30 (variable) 31 -130.80634 2.2 1.94594 17.98 32 -67.89935 0.8 33 -163.52036 1.25 1.56883 31.71 34 37.07534 D34 (variable) 35 66.52215 4.75 1.80100 48.75 36 -175.782 D36 (variable) 37* -73.66538 1.9 1.71999 82.57 38 282.5465 BF [Aspherical Data] The 26th surface κ = 0.00, A4 = -2.17E-06, A6 = 1.23E-09 A8 = -8.20E-12, A10 = 2.53E-14, A12 = -2.96E-17 The 37th surface κ = 0.00, A4 = 9.91E-08, A6 = 2.50E-09 A8 = -1.38E-11, A10 = 4.59E-14, A12 = -5.72E-17 [Lens Group Data] Group Starting Surface Focal Length G1 1 139.63445 G2 6 -43.68068 G3 14 93.7469 G4 16 86.63044 G5 31 -83.20858 G6 35 60.77856 G7 37 -80.9748 [Variable Interval Data] W M T W M T Infinity Infinity Infinity Close Distance Close Distance Close Distance f 71.49616 135 196.00002 ― ― ― β ― ― ― -0.08386 -0.14611 -0.20261 D5 1.98083 33.88478 49.73838 1.98083 33.88478 49.73838 D13 47.67943 16.00066 1.60866 47.67943 16.00066 1.60866 D15 2.53884 2.31366 0.85206 2.53884 2.31366 0.85206 D30 6.84927 7.75031 3.99572 8.37353 13.43196 15.53626 D34 26.8749 21.64199 27.84545 23.36912 9.9946 4.76438 D36 6.00155 10.33343 7.88455 7.98308 16.29916 19.42509 [Conditional corresponding value] Conditional expression (1) f3 / (-fE)=1.16 Conditional expression (2) f1 / (-fE)=1.72 Conditional expression (3) f2 / fE=0.54 Conditional expression (4) f1 / (-f2)=3.20 Conditional expression (5) f1 / f3=1.49 Conditional expression (6) f1 / f4=1.61 Conditional expression (7) (-fF1) / fF2=1.37 Conditional expression (8) νdP=27.35 Conditional expression (9) ndP+(0.01425×νdP)=2.0536 Conditional expression (10) θgFP+(0.00316×νdP)=0.7183 Conditional expression (11) 2ωw=33.81° Conditional expression (12) 2ωt=12.27° Conditional expression (13) BFw / fw=0.51

[0108] Figures 4(A), 4(B), and 4(C) are aberration diagrams in the wide-angle end state, intermediate focal length state, and telephoto end state of the zoom optical system according to the second embodiment, respectively. From each aberration diagram, it can be seen that the zoom optical system according to the second embodiment has well-corrected aberrations and excellent imaging performance.

[0109] (Third Embodiment) The third embodiment will be described with reference to FIGS. 5 to 6 and Table 3. FIG. 5 is a diagram showing the movement of lenses when the zoom optical system according to the third embodiment changes from the wide-angle end state to the telephoto end state. The zoom optical system ZL(3) according to the third embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, a sixth lens group G6 having a positive refractive power, a seventh lens group G7 having a negative refractive power, an eighth lens group G8 having a positive refractive power, a ninth lens group G9 having a positive refractive power, and a tenth lens group G10 having a negative refractive power. When zooming from the wide-angle end state to the telephoto end state, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, the seventh lens group G7, the eighth lens group G8, and the ninth lens group G9 move separately in the directions indicated by the arrows in FIG. 5, and the intervals between adjacent lens groups change. Note that, during zooming, the first lens group G1, the sixth lens group G6, and the tenth lens group G10 are fixed with respect to the image plane I. The lens group composed of the fourth lens group G4, the fifth lens group G5, the sixth lens group G6, the seventh lens group G7, the eighth lens group G8, the ninth lens group G9, and the tenth lens group G10 corresponds to the subsequent lens group GR.

[0110] The first lens group G1 is composed of a cemented lens of a negative meniscus lens L11 with a convex surface facing the object side and a biconvex positive lens L12 arranged in order from the object side, and a positive meniscus lens L13 with a convex surface facing the object side.

[0111] The second lens group G2 is composed of a negative meniscus lens L21 with a convex surface facing the object side, a biconcave negative lens L22, a positive meniscus lens L23 with a convex surface facing the object side, and a biconcave negative lens L24 arranged in order from the object side.

[0112] The third lens group G3 is composed of a positive meniscus lens L31 with a convex surface facing the object side.

[0113] The fourth lens group G4 is composed of a biconvex positive lens L41 and a positive meniscus lens L42 with its convex surface facing the object side, arranged in order from the object side.

[0114] The fifth lens group G5 is composed of a cemented lens of a biconcave negative lens L51 and a biconvex positive lens L52. An aperture stop S is disposed on the most object side of the fifth lens group G5 and moves together with the fifth lens group G5 during zooming.

[0115] The sixth lens group G6 is composed of, arranged in order from the object side, a negative meniscus lens L61 with its convex surface facing the object side, a cemented lens of a biconvex positive lens L62 and a negative meniscus lens L63 with its concave surface facing the object side, and a positive meniscus lens L64 with its convex surface facing the object side. The positive lens L62 has an aspherical lens surface on the object side.

[0116] The seventh lens group G7 is composed of a biconvex positive lens L71 and a negative meniscus lens L72 with its convex surface facing the object side, arranged in order from the object side.

[0117] The eighth lens group G8 is composed of a positive meniscus lens L81 with its convex surface facing the object side.

[0118] The ninth lens group G9 is composed of a positive meniscus lens L91 with its concave surface facing the object side. The positive meniscus lens L91 has an aspherical lens surface on the object side.

[0119] The tenth lens group G10 is composed of a biconcave negative lens L101. An image plane I is disposed on the image side of the tenth lens group G10. That is, the tenth lens group G10 corresponds to the final lens group.

[0120] In this embodiment, by moving the seventh lens group G7 toward the image plane I side and moving the eighth lens group G8 toward the object side, focusing is performed from a distant object to a near object (from an infinite object to a finite distance object). That is, the seventh lens group G7 corresponds to the first focusing lens group, and the eighth lens group G8 corresponds to the second focusing lens group.

[0121] Table 3 below lists the specifications of the zoom optical system according to the third embodiment.

[0122] (Table 3) [Overall specifications] Zoom ratio 2.74 θgFP = 0.6319 W M T FNO 2.8471 2.86934 2.91965 2ω 33.70556 17.86124 12.26972 Y 21.70 21.70 21.70 TL 207.00792 207.00792 207.00792 Bf 32.57205 32.57205 32.57205 [Lens specifications] Surface number R D nd νd θgF 1 101.99194 2.80 2.00100 29.12 2 78.37407 9.70 1.49782 82.57 3 -1022.4124 0.10 4 75.80458 7.70 1.43385 95.23 5 278.09823 D5 (variable) 6 67.03073 1.90 1.60300 65.44 7 29.65154 7.20 8 -4189.1769 1.60 1.49782 82.57 9 72.21235 2.92 10 41.05723 3.70 1.66382 27.35 0.6319 11 51.79281 6.99 12 -47.57525 1.90 1.49782 82.57 13 876.17776 D13 (variable) 14 75.45331 3.20 1.94594 17.98 15 263.87074 D15 (variable) 16 99.38463 4.70 1.49782 82.57 17 -385.66566 0.10 18 69.30883 3.85 1.49782 82.57 19 1544.1877 D19 (Variable) 20 ∞ 3.50 (Aperture S) 21 -84.39308 1.80 1.92286 20.88 22 76.70869 5.00 1.49782 82.57 23 -157.06149 D23 (Variable) 24 168.47838 1.70 1.85026 32.35 25 77.42169 2.00 26* 59.12213 7.70 1.59349 67 27 -51.6115 1.70 1.62004 36.4 28 -89.79626 1.30 29 87.29534 2.70 1.80100 34.92 30 136.2385 D30 (Variable) 31 627.77024 2.00 1.94594 17.98 32 -206.69697 0.80 33 386.92798 1.25 1.71300 53.96 34 42.23229 D34 (Variable) 35 66.92449 4.00 1.90265 35.77 36 418.69787 D36 (Variable) 37* -553.02647 3.00 1.55518 71.49 38 -77.65664 D38 (Variable) 39 -70.45081 1.90 1.56384 60.71 40 88.47517 BF [Aspherical Data] The 26th surface κ = 0.00, A4 = -2.06E-06, A6 = 3.72E-10 A8 = -2.74E-12, A10 = 1.30E-14, A12 = -1.97E-17 Page 37 κ = 0.00, A4 = -5.43E-07, A6 = 5.65E-10 A8 = -1.54E-12, A10 = 4.63E-15, A12 = -5.42E-18 [Lens Group Data] Group Starting Surface Focal Length G1 1 124.35572 G2 6 -34.94136 G3 14 110.79292 G4 16 76.69466 G5 20 -76.01113 G6 24 72.09875 G7 31 -114.02434 G8 35 87.7742 G9 37 162.36222 G10 39 -69.26098 [Variable Interval Data] W M T W M T Infinity Infinity Infinity Close Distance Close Distance Close Distance f 71.48828 135 196 ― ― ― β ― ― ― -0.08481 -0.15088 -0.20696 D5 3.14675 27.96403 40.90704 3.14675 27.96403 40.90704 D13 29.53764 8.15958 1.60832 29.53764 8.15958 1.60832 D15 19.15996 9.78302 1.19195 19.15996 9.78302 1.19195 D19 4.5 8.45422 8.9974 4.5 8.45422 8.9974 D23 1.47462 3.45814 5.11428 1.47462 3.45814 5.11428 D30 3.7091 6.11122 3.97416 5.8438 13.08039 18.03258 D34 35.19368 27.95231 37.56575 29.85694 10.52937 3.82554 D36 3.33819 8.98173 3.81873 6.54023 19.4355 23.50052 D38 8.23679 7.4325 5.11912 8.23679 7.4325 5.11912 [Conditional corresponding value] Conditional expression (1) f3 / (-fE)=1.60 Conditional expression (2) f1 / (-fE)=1.80 Conditional expression (3) f2 / fE=0.50 Conditional expression (4) f1 / (-f2)=3.56 Conditional expression (5) f1 / f3=1.12 Conditional expression (6) f1 / f4=1.62 Conditional expression (7) (-fF1) / fF2=1.30 Conditional expression (8) νdP=27.35 Conditional expression (9) ndP+(0.01425×νdP)=2.0536 Conditional expression (10) θgFP+(0.00316×νdP)=0.7183 Conditional expression (11) 2ωw=33.71° Conditional expression (12) 2ωt=12.27° Conditional expression (13) BFw / fw=0.46

[0123] FIG. 6(A), FIG. 6(A), and FIG. 6(C) are aberration diagrams in the wide-angle end state, intermediate focal length state, and telephoto end state of the zoom optical system according to the third embodiment, respectively. From each aberration diagram, it can be seen that the zoom optical system according to the third embodiment has well-corrected aberrations and excellent imaging performance.

[0124] (Fourth Embodiment) The fourth embodiment will be described with reference to FIGS. 7 to 8 and Table 4. FIG. 7 is a diagram showing the movement of lenses when the zoom optical system according to the fourth embodiment changes from the wide-angle end state to the telephoto end state. The zoom optical system ZL(4) according to the fourth embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a positive refractive power, a sixth lens group G6 having a negative refractive power, a seventh lens group G7 having a positive refractive power, and an eighth lens group G8 having a negative refractive power. When zooming from the wide-angle end state to the telephoto end state, the second lens group G2, the third lens group G3, the fourth lens group G4, the sixth lens group G6, and the seventh lens group G7 move separately in the directions indicated by the arrows in FIG. 7, and the intervals between adjacent lens groups change. Note that, during zooming, the first lens group G1, the fifth lens group G5, and the eighth lens group G8 are fixed with respect to the image plane I. The lens group composed of the fourth lens group G4, the fifth lens group G5, the sixth lens group G6, the seventh lens group G7, and the eighth lens group G8 corresponds to the subsequent lens group GR.

[0125] The first lens group G1 is composed of a cemented lens of a negative meniscus lens L11 with a convex surface facing the object side and a biconvex positive lens L12 arranged in order from the object side, and a positive meniscus lens L13 with a convex surface facing the object side.

[0126] The second lens group G2 is composed of a negative meniscus lens L21 with a convex surface facing the object side, a biconcave negative lens L22, a positive meniscus lens L23 with a convex surface facing the object side, and a biconcave negative lens L24 arranged in order from the object side.

[0127] The third lens group G3 is composed of a positive meniscus lens L31 with a convex surface facing the object side.

[0128] The fourth lens group G4 is composed of a biconvex positive lens L41 and a positive meniscus lens L42 with a convex surface facing the object side arranged in order from the object side.

[0129] The fifth lens group G5 is composed of a cemented lens of a biconcave negative lens L51 and a biconvex positive lens L52 arranged in order from the object side, a negative meniscus lens L53 with its convex surface facing the object side, a cemented lens of a biconvex positive lens L54 and a negative meniscus lens L55 with its concave surface facing the object side, and a positive meniscus lens L56 with its convex surface facing the object side. An aperture stop S is disposed on the most object side of the fifth lens group G5 and is fixed to the image plane I together with the fifth lens group G5 during zooming. The positive lens L54 has an aspherical lens surface on the object side.

[0130] The sixth lens group G6 is composed of a positive meniscus lens L61 with its concave surface facing the object side and a negative meniscus lens L62 with its convex surface facing the object side, arranged in order from the object side.

[0131] The seventh lens group G7 is composed of a biconvex positive lens L71.

[0132] The eighth lens group G8 is composed of a negative meniscus lens L81 with its convex surface facing the object side and a negative meniscus lens L82 with its concave surface facing the object side, arranged in order from the object side. The negative meniscus lens L81 has an aspherical lens surface on the object side. The image plane I is disposed on the image side of the eighth lens group G8. That is, the eighth lens group G8 corresponds to the final lens group.

[0133] In this embodiment, by moving the sixth lens group G6 toward the image plane I side and moving the seventh lens group G7 toward the object side, focusing from a distant object to a near object (from an infinite object to a finite distance object) is performed. That is, the sixth lens group G6 corresponds to the first focusing lens group, and the seventh lens group G7 corresponds to the second focusing lens group.

[0134] The following Table 4 lists the values of the specifications of the zoom optical system according to the fourth embodiment.

[0135] (Table 4) [Overall specifications] Zoom ratio 2.74 θgFP = 0.6319 W M T FNO 2.88923 2.87811 2.87676 2ω 33.62692 17.8017 12.26826 Y 21.70 21.70 21.70 TL 207.00795 207.00795 207.00795 BF 32.57205 32.57205 32.57205 [Lens Specifications] Surface Number R D nd νd θgF 1 104.96946 2.80 2.00100 29.12 2 81.23029 9.70 1.49782 82.57 3 -5013.309 0.10 4 98.76892 7.70 1.43385 95.23 5 349.12389 D5 (Variable) 6 62.87568 1.90 1.60300 65.44 7 32.61551 8.00 8 -1223.4377 1.60 1.49782 82.57 9 88.74378 2.77 10 43.50207 3.70 1.66382 27.35 0.6319 11 56.12991 7.85 12 -59.98159 1.90 1.49782 82.57 13 180.55889 D13 (Variable) 14 72.53962 3.20 1.94594 17.98 15 224.56923 D15 (Variable) 16 107.03817 4.70 1.49782 82.57 17 -183.81713 0.10 18 54.21049 3.85 1.49782 82.57 19 173.7794 D19 (Variable) 20 ∞ 3.50 (Aperture S) 21 -89.65067 1.80 1.92286 20.88 22 53.92556 5.00 1.49782 82.57 23 -180.67725 1.50 24 151.38095 1.70 1.85026 32.35 25 72.515 2.00 26* 60.75581 7.70 1.59349 67 27 -54.39087 1.70 1.62004 36.4 28 -94.7071 1.30 29 58.34653 2.70 1.80100 34.92 30 116.10532 D30 (variable) 31 -642.22297 2.00 1.94594 17.98 32 -108.81859 0.80 33 1100.6245 1.25 1.71300 53.96 34 36.03135 D34 (variable) 35 70.63159 3.85 1.90265 35.77 36 -359.66973 D36 (variable) 37* 1093.756 1.90 1.53793 55.01 38 73.85081 8.76 39 -68.15582 1.90 1.56384 60.71 40 -183.66574 BF [Aspherical Data] The 26th surface κ = 0.00, A4 = -1.87E-06, A6 = -4.52E-10 A8 = 3.30E-12, A10 = -9.39E-15, A12 = 1.05E-17 The 37th surface κ = 0.00, A4 = -5.10E-07, A6 = 2.18E-09 A8 = -1.11E-11, A10 = 3.84E-14, A12 = -5.02E-17 [Lens Group Data] Group Starting Surface Focal Length G1 1 151.31596 G2 6 -40.77182 G3 14 112.1271 G4 16 73.19762 G5 20 204.39955 G6 31 -85.38342 G7 35 65.68378 G8 37 -81.7079 [Variable Interval Data] W M T W M T Infinity Infinity Infinity Close Distance Close Distance Close Distance f 71.48789 135 196.00001 ― ― ― β ― ― ― -0.08409 -0.14666 -0.20387 D5 1.85197 33.16708 49.31235 1.85197 33.16708 49.31235 D13 39.7348 11.81928 1.60349 39.7348 11.81928 1.60349 D15 16.28719 9.45385 1.9819 16.28719 9.45385 1.9819 D19 4.5 7.93374 9.47621 4.5 7.93374 9.47621 D30 3.7 5.7618 4.22253 4.95966 10.39125 14.39741 D34 29.10973 22.62707 26.97381 25.70866 11.51639 4.5890 D36 2.5956 7.01646 4.209 4.73702 13.49769 16.41886 [Conditional Equation Corresponding Values] Conditional Equation (1) f3 / (-fE)=1.37 Conditional Equation (2) f1 / (-fE)=1.85 Conditional Equation (3) f2 / fE=0.50 Conditional expression (4) f1 / (-f2) = 3.71 Conditional expression (5) f1 / f3 = 1.35 Conditional expression (6) f1 / f4 = 2.07 Conditional expression (7) (-fF1) / fF2 = 1.30 Conditional expression (8) νdP = 27.35 Conditional expression (9) ndP + (0.01425 × νdP) = 2.0536 Conditional expression (10) θgFP + (0.00316 × νdP) = 0.7183 Conditional expression (11) 2ωw = 33.63° Conditional expression (12) 2ωt = 12.27° Conditional expression (13) BFw / fw = 0.456

[0136] FIG. 8(A), FIG. 8(B), and FIG. 8(C) are aberration diagrams in the wide-angle end state, intermediate focal length state, and telephoto end state of the zoom optical system according to the fourth embodiment, respectively. From each aberration diagram, it can be seen that the zoom optical system according to the fourth embodiment has well-corrected aberrations and excellent imaging performance.

[0137] (Fifth Embodiment) The fifth embodiment will be described with reference to FIGS. 9 to 10 and Table 5. FIG. 9 is a diagram showing the movement of lenses when the zoom optical system according to the fifth embodiment changes from the wide-angle end state to the telephoto end state. The zoom optical system ZL(5) according to the fifth embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, a sixth lens group G6 having a positive refractive power, a seventh lens group G7 having a negative refractive power, an eighth lens group G8 having a positive refractive power, and a ninth lens group G9 having a negative refractive power. When zooming from the wide-angle end state to the telephoto end state, the second lens group G2, the third lens group G3, the fifth lens group G5, the seventh lens group G7, and the eighth lens group G8 move separately in the directions indicated by the arrows in FIG. 9, and the intervals between adjacent lens groups change. Note that, during zooming, the first lens group G1, the fourth lens group G4, the sixth lens group G6, and the ninth lens group G9 are fixed with respect to the image plane I. The lens group composed of the fourth lens group G4, the fifth lens group G5, the sixth lens group G6, the seventh lens group G7, the eighth lens group G8, and the ninth lens group G9 corresponds to the subsequent lens group GR.

[0138] The first lens group G1 is composed of, in order from the object side, a cemented lens of a negative meniscus lens L11 with a convex surface facing the object side and a biconvex positive lens L12, and a positive meniscus lens L13 with a convex surface facing the object side.

[0139] The second lens group G2 is composed of, in order from the object side, a negative meniscus lens L21 with a convex surface facing the object side, a biconvex positive lens L22, a biconcave negative lens L23, and a negative meniscus lens L24 with a concave surface facing the object side.

[0140] The third lens group G3 is composed of a positive meniscus lens L31 with a convex surface facing the object side.

[0141] The fourth lens group G4 is composed of, in order from the object side, a positive meniscus lens L41 with a convex surface facing the object side and a biconvex positive lens L42.

[0142] The fifth lens group G5 is composed of a cemented lens of a biconcave negative lens L51 and a positive meniscus lens L52 with its convex surface facing the object side. An aperture stop S is disposed on the most object side of the fifth lens group G5 and moves together with the fifth lens group G5 during zooming.

[0143] The sixth lens group G6 is composed of, arranged in order from the object side, a negative meniscus lens L61 with its convex surface facing the object side, a biconvex positive lens L62, and a positive meniscus lens L63 with its convex surface facing the object side. The positive lens L62 has an aspherical lens surface on the image side.

[0144] The seventh lens group G7 is composed of, arranged in order from the object side, a positive meniscus lens L71 with its concave surface facing the object side and a biconcave negative lens L72.

[0145] The eighth lens group G8 is composed of a biconvex positive lens L81.

[0146] The ninth lens group G9 is composed of a biconcave negative lens L91. An image plane I is disposed on the image side of the ninth lens group G9. That is, the ninth lens group G9 corresponds to the final lens group.

[0147] In this embodiment, by moving the seventh lens group G7 toward the image plane I side and moving the eighth lens group G8 toward the object side, focusing from a distant object to a near object (from an infinite object to a finite distance object) is performed. That is, the seventh lens group G7 corresponds to the first focusing lens group, and the eighth lens group G8 corresponds to the second focusing lens group.

[0148] The following Table 5 lists the values of the specifications of the zoom optical system according to the fifth embodiment.

[0149] (Table 5) [Overall specifications] Zoom ratio 2.74 θgFP = 0.625146 W M T FNO 2.79867 2.84973 2.88046 2ω 33.269 17.64798 12.20244 Y 21.70 21.70 21.70 TL 194.00000 194.00000 194.00000 BF 32.56419 32.56419 32.56419 [Lens Specifications] Surface Number R D nd νd θgF 1 142.398 2.80 1.85000 27.03 2 89.22539 11.50 1.49782 82.57 3 -475.12414 0.20 4 78.29293 7.00 1.43385 95.23 5 169.60505 D5 (Variable) 6 2649.01093 2.00 1.55705 45.85 7 40.96873 5.00 8 91.52844 7.00 1.80809 22.74 9 -108.37528 0.10 10 -300.55351 1.60 1.49782 82.57 11 49.61316 9.00 12 -50.05975 2.00 1.66046 27.57 0.625146 13 -282.49474 D13 (Variable) 14 62.00807 3.50 1.92286 20.88 15 104.61485 D15 (Variable) 16 71.46374 5.00 1.49782 82.57 17 705.70649 0.10 18 54.57663 6.50 1.60300 65.44 19 -278.60199 D19 (Variable) 20 ∞ 3.00 (Aperture S) 21 -104.70389 1.80 1.90499 26.68 22 30.2441 5.00 1.51188 68.34 23 130.63306 D23 (Variable) 24 39.55621 1.80 1.79124 28.25 25 31.45913 1.00 26 35.35387 7.00 1.55332 71.68 27* -111.74355 1.00 28 58.49751 2.50 1.81057 40.15 29 105.99178 D29 (Variable) 30 -286.5457 2.00 1.94594 17.98 31 -84.48026 0.80 32 -270.24499 1.25 1.59349 67 33 32.39702 D33 (Variable) 34 77.85755 4.80 1.80100 34.92 35 -88.13641 D35 (Variable) 36 -75.46523 2.00 1.72200 34.56 37 104.96677 BF [Aspherical Data] The 27th surface κ = 0.00, A4 = 2.11E-06, A6 = -1.20E-09 A8 = -2.82E-13, A10 = -3.58E-15, A12 = 0.00E+00 [Lens Group Data] Group Starting Surface Focal Length G1 1 164.12723 G2 6 -47.62588 G3 14 158.7209 G4 16 52.56296 G5 20 -38.49179 G6 24 46.69749 G7 30 -80.39666 G8 34 52.28209 G9 36 -60.52463 [Variable interval data] W M T W M T Infinity Infinity Infinity Close distance Close distance Close distance f 71.5 135 196 ― ― ― β ― ― ― -0.0839 -0.14665 -0.20273 D5 3.50002 37.12414 54.5663 3.50002 37.12414 54.5663 D13 37.00636 10.01061 2 37.00636 10.01061 2 D15 18.05993 11.43157 2 18.05993 11.43157 2 D19 3.82591 6.93485 8.82776 3.82591 6.93485 8.82776 D23 7.16459 4.05564 2.16276 7.16459 4.05564 2.16276 D29 4.89453 5.25712 2.03164 6.68467 11.36918 13.66092 D33 16.59265 15.71825 22.606 13.60117 5.68565 3 D35 5.706 6.21782 2.55555 6.90733 10.13836 10.53228 [Condition formula corresponding value] Condition formula (1) f3 / (-fE)=2.62 Condition formula (2) f1 / (-fE)=2.71 Condition formula (3) f2 / fE=0.79 Condition formula (4) f1 / (-f2)=3.45 Condition formula (5) f1 / f3=1.03 Condition formula (6) f1 / f4=3.12 Condition formula (7) (-fF1) / fF2=1.54 Condition formula (8) νdP=27.57 Conditional expression (9): ndP+(0.01425×νdP)=2.0533 Conditional expression (10): θgFP+(0.00316×νdP)=0.7123 Conditional expression (11): 2ωw=33.27° Conditional expression (12): 2ωt=12.20° Conditional expression (13): BFw / fw=0.46

[0150] FIG. 10(A), FIG. 10(B), and FIG. 10(C) are aberration diagrams of the variable magnification optical system according to the fifth embodiment in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively. From each aberration diagram, it can be seen that the variable magnification optical system according to the fifth embodiment has well-corrected aberrations and excellent imaging performance.

[0151] (Sixth Embodiment) The sixth embodiment will be described with reference to FIGS. 11 to 12 and Table 6. FIG. 11 is a diagram showing the movement of the lens when the variable magnification optical system according to the sixth embodiment changes from the wide-angle end state to the telephoto end state. The variable magnification optical system ZL(6) according to the sixth embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, a sixth lens group G6 having a positive refractive power, a seventh lens group G7 having a negative refractive power, an eighth lens group G8 having a positive refractive power, and a ninth lens group G9 having a negative refractive power. When zooming from the wide-angle end state to the telephoto end state, the second lens group G2, the third lens group G3, the fifth lens group G5, the seventh lens group G7, and the eighth lens group G8 move separately in the directions indicated by the arrows in FIG. 11, and the intervals between adjacent lens groups change. Note that when zooming, the first lens group G1, the fourth lens group G4, the sixth lens group G6, and the ninth lens group G9 are fixed with respect to the image plane I. The lens group composed of the fourth lens group G4, the fifth lens group G5, the sixth lens group G6, the seventh lens group G7, the eighth lens group G8, and the ninth lens group G9 corresponds to the subsequent lens group GR.

[0152] The first lens group G1 is composed of a cemented lens of a negative meniscus lens L11 with a convex surface facing the object side and a biconvex positive lens L12 arranged in order from the object side, and a positive meniscus lens L13 with a convex surface facing the object side.

[0153] The second lens group G2 is composed of a negative meniscus lens L21 with a convex surface facing the object side, a negative lens L22 with a biconcave shape, a positive meniscus lens L23 with a convex surface facing the object side, and a negative lens L24 with a biconcave shape arranged in order from the object side.

[0154] The third lens group G3 is composed of a positive meniscus lens L31 with a convex surface facing the object side.

[0155] The fourth lens group G4 is composed of a biconvex positive lens L41. The lens surface on the object side of the positive lens L41 is an aspherical surface.

[0156] The fifth lens group G5 is composed of a cemented lens of a biconcave negative lens L51 and a biconvex positive lens L52. An aperture stop S is disposed on the most object side of the fifth lens group G5 and moves together with the fifth lens group G5 during zooming.

[0157] The sixth lens group G6 is composed of a cemented lens of a negative meniscus lens L61 with a convex surface facing the object side, a biconvex positive lens L62, and a negative meniscus lens L63 with a concave surface facing the object side arranged in order from the object side, and a positive meniscus lens L64 with a convex surface facing the object side. The lens surface on the object side of the positive lens L62 is an aspherical surface.

[0158] The seventh lens group G7 is composed of a biconvex positive lens L71 and a biconcave negative lens L72 arranged in order from the object side.

[0159] The eighth lens group G8 is composed of a biconvex positive lens L81.

[0160] The ninth lens group G9 is composed of a biconcave negative lens L91 and a negative meniscus lens L92 with its concave surface facing the object side, arranged in order from the object side. The negative lens L91 has an aspherical lens surface on the object side. An image plane I is arranged on the image side of the ninth lens group G9. That is, the ninth lens group G9 corresponds to the final lens group.

[0161] In this embodiment, by moving the seventh lens group G7 toward the image plane I side and moving the eighth lens group G8 toward the object side, focusing is performed from a distant object to a near object (from an infinite object to a finite distance object). That is, the seventh lens group G7 corresponds to the first focusing lens group, and the eighth lens group G8 corresponds to the second focusing lens group.

[0162] The following Table 6 lists the values of the specifications of the zoom optical system according to the sixth embodiment.

[0163] (Table 6) [Overall specifications] Zoom ratio 2.74 θgFP = 0.6319 W M T FNO 2.83129 2.85335 2.87996 2ω 33.76242 17.81528 12.26938 Y 21.70 21.70 21.70 TL 191.79997 191.79997 191.79997 BF 32.65404 32.65404 32.65404 [Lens specifications] Surface number R D nd νd θgF 1 113.29192 2.8 2.001 29.12 2 81.40925 10.5 1.49782 82.57 3 -795.64249 0.1 4 74.88525 8.2 1.433848 95.23 5 376.798 D5 (variable) 6 82.73428 1.9 1.59349 67 7 31.04017 9.35 8 -168.77759 1.6 1.49782 82.57 9 115.02437 0.8 10 41.14809 3.8 1.663819 27.35 0.6319 11 73.00001 5.6 12 -61.06953 1.9 1.49782 82.57 13 98.51376 D13 (variable) 14 86.14679 3.4 1.94595 17.98 15 694.90071 D15 (variable) 16* 52.81421 8 1.553319 71.68 17 -117.98245 D17 (variable) 18 ∞ 3.7 (Aperture S) 19 -65.12937 1.8 1.92286 20.88 20 57.80344 5.30 1.49782 82.57 21 -111.65652 D21 (variable) 22 92.32113 1.7 1.935421 18.16 23 60.00966 2 24* 58.92406 7.60 1.59201 66.89 25 -55 1.7 1.62004 36.4 26 -91.54022 1.3 27 59.23711 2.8 1.746869 23.4 28 126.70086 D28 (variable) 29 448.34721 2.4 1.94595 17.98 30 -94.32707 0.8 31 -205.67313 1.25 1.794772 36.19 32 38.13601 D32 (variable) 33 112.2489 3.85 1.90265 35.72 34 -112.24891 D34 (Variable) 35* -72.74439 1.9 1.49782 82.57 36 498.35011 4.9 37 -37.82283 1.90 1.716676 52.08 38 -51.98812 BF [Aspherical Data] Surface 16 κ = 0.00, A4 = 2.07E-07, A6 = 1.58E-10 A8 = -2.50E-13, A10 = 2.86E-16, A12 = 0.00E+00 Surface 24 κ = 0.00, A4 = -1.36E-06, A6 = 6.98E-10 A8 = -4.57E-12, A10 = 1.66E-14, A12 = -2.22E-17 Surface 35 κ = 0.00, A4 = 1.84E-07, A6 = 3.48E-09 A8 = -1.61E-11, A10 = 6.41E-14, A12 = -9.19E-17 [Lens Group Data] Group Starting Surface Focal Length G1 1 126.73821 G2 6 -35.76434 G3 14 103.67509 G4 16 67.05334 G5 18 -59.65998 G6 22 57.09316 G7 29 -82.17953 G8 33 62.68745 G9 35 -77.91319 [Variable Interval Data] W M T W M T Infinity Infinity Infinity Close Distance Close Distance Close Distance f 71.49323 135 196 ― ― ― β ― ― ― -0.08339 -0.14602 -0.1994 D5 1.6 28.92133 42.60181 1.6 28.92133 42.60181 D13 30.28784 9.66169 1.59632 30.28784 9.66169 1.59632 D15 13.82513 7.12995 1.51484 13.82513 7.12995 1.51484 D17 4.5 6.8522 7.51331 4.50 6.85 7.51 D21 4.51511 2.16291 1.5018 4.51511 2.16291 1.5018 D28 4.04215 6.41537 4.00083 5.37286 11.89757 14.49678 D32 22.88318 19.60826 26.72334 19.55641 8.36976 4.68183 D34 7.29656 8.19826 3.49773 9.29262 13.95456 15.04328 [Conditional corresponding value] Conditional expression (1) f3 / (-fE)=1.33 Conditional expression (2) f1 / (-fE)=1.63 Conditional expression (3) f2 / fE=0.46 Conditional expression (4) f1 / (-f2)=3.54 Conditional expression (5) f1 / f3=1.22 Conditional expression (6) f1 / f4=1.89 Conditional expression (7) (-fF1) / fF2=1.31 Conditional expression (8) νdP=27.35 Conditional expression (9) ndP+(0.01425×νdP)=2.0536 Conditional expression (10) θgFP+(0.00316×νdP)=0.7183 Conditional expression (11) 2ωw=33.76° Conditional expression (12) 2ωt=12.27° Conditional expression (13) BFw / fw=0.46

[0164] FIG. 12(A), FIG. 12(B), and FIG. 12(C) are aberration diagrams in the wide-angle end state, intermediate focal length state, and telephoto end state of the zoom optical system according to the sixth embodiment, respectively. From each aberration diagram, it can be seen that the zoom optical system according to the sixth embodiment has well-corrected aberrations and excellent imaging performance.

[0165] (Seventh Embodiment) The seventh embodiment will be described with reference to FIGS. 13 to 14 and Table 7. FIG. 13 is a diagram showing the movement of the lenses when the zoom optical system according to the seventh embodiment changes from the wide-angle end state to the telephoto end state. The zoom optical system ZL(7) according to the seventh embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, a fifth lens group G5 having a positive refractive power, and a sixth lens group G6 having a negative refractive power. When zooming from the wide-angle end state to the telephoto end state, the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 move separately in the directions indicated by the arrows in FIG. 13, and the intervals between adjacent lens groups change. Note that, during zooming, the first lens group G1 and the sixth lens group G6 are fixed with respect to the image plane I. The lens group composed of the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 corresponds to the subsequent lens group GR.

[0166] The first lens group G1 is composed of a cemented lens of a negative meniscus lens L11 with a convex surface facing the object side and a biconvex positive lens L12 arranged in order from the object side, and a positive meniscus lens L13 with a convex surface facing the object side.

[0167] The second lens group G2 is composed of a negative meniscus lens L21 with a convex surface facing the object side, a biconcave negative lens L22, a positive meniscus lens L23 with a convex surface facing the object side, and a negative meniscus lens L24 with a concave surface facing the object side, arranged in order from the object side.

[0168] The third lens group G3 is composed of, arranged in order from the object side, a positive meniscus lens L31 with a convex surface facing the object side, a positive meniscus lens L32 with a convex surface facing the object side, a positive lens L33 with a biconvex shape, a negative lens L34 with a biconcave shape, and a cemented lens of a positive meniscus lens L35 with a convex surface facing the object side, a negative meniscus lens L36 with a convex surface facing the object side, a cemented lens of a positive lens L37 with a biconvex shape and a negative meniscus lens L38 with a concave surface facing the object side, and a positive meniscus lens L39 with a convex surface facing the object side. An aperture stop S is disposed between the positive lens L33 and the negative lens L34 in the third lens group G3 and moves together with the third lens group G3 during zooming. The positive lens L37 has an aspherical lens surface on the object side.

[0169] The fourth lens group G4 is composed of, arranged in order from the object side, a positive meniscus lens L41 with a concave surface facing the object side and a negative lens L42 with a biconcave shape.

[0170] The fifth lens group G5 is composed of a positive lens L51 with a biconvex shape.

[0171] The sixth lens group G6 is composed of a negative meniscus lens L61 with a concave surface facing the object side. The negative meniscus lens L61 has an aspherical lens surface on the object side. An image plane I is disposed on the image side of the sixth lens group G6. That is, the sixth lens group G6 corresponds to the final lens group.

[0172] In this embodiment, by moving the fourth lens group G4 toward the image plane I side and moving the fifth lens group G5 toward the object side, focusing is performed from a distant object to a near object (from an infinite object to a finite distance object). That is, the fourth lens group G4 corresponds to the first focusing lens group, and the fifth lens group G5 corresponds to the second focusing lens group.

[0173] The following Table 7 lists the values of the specifications of the zoom optical system according to the seventh embodiment.

[0174] (Table 7) [Overall specifications] Zoom ratio 2.74 θgFP = 0.6319 WMT FNO 2.91966 2.90716 2.86166 2ω 34.08866 17.93464 12.307 Y 21.70 21.70 21.70 TL 208.41341 208.41341 208.41341 BF 31.14475 31.14475 31.14475 [Lens Specifications] Surface Number R D nd νd θgF 1 135.3501 2.8 1.911144 31.13 2 88.2984 9.7 1.49782 82.57 3 -2014.0365 0.1 4 87.0008 7.7 1.433848 95.23 5 1270.4367 D5 (Variable) 6 96.7322 1.9 1.580538 67.89 7 32.0715 9.4 8 -149.5985 1.6 1.49782 82.57 9 84.947 0.8 10 47.7033 4.1051 1.663819 27.35 0.6319 11 132.9068 4.917 12 -59.1191 1.9 1.49782 82.57 13 -410.9838 D13 (Variable) 14 75.2493 4.0117 1.919756 30.42 15 406.1688 3 16 110.8456 3 1.643929 59.34 17 221.1361 0.1 18 55.6433 5 1.510139 69.79 19 -452.609 4.5 20 ∞ 3.5 (Aperture S) 21 -128.1374 1.8 1.924139 29.82 22 38.7647 4.2 1.513006 67.44 23 324.5195 4.1 24 111.4412 1.7 1.77151 22.51 25 58.0313 1.7 26* 61.5731 8.5 1.593493 67 27 -26.7185 1.7 1.627041 46.96 28 -76.4024 1.3 29 47.8194 2.5 1.772125 44.63 30 60.849 D30 (variable) 31 -289.2655 2.2 1.945944 17.98 32 -56.7163 0.8 33 -62.5979 1.25 1.631431 31.71 34 46.593 D34 (variable) 35 84.1615 4.75 1.764819 48.75 36 -185.6155 D36 (variable) 37* -52.3045 1.9 1.49782 82.57 38 -319.0332 BF [Aspherical Data] The 26th surface κ = 0.00, A4 = -1.61284E-06, A6 = 4.35900E-10 A8 = -1.44229E-12, A10 = 4.99341E-15, A12 = -5.72670E-18 The 37th surface κ = 0.00, A4 = 7.70231E-07, A6 = 2.20982E-09 A8 = -9.92801E-12, A10 = 2.79429E-14, A12 = -2.96640E-17 [Lens Group Data] Group Starting Surface Focal Length G1 1 145.20607 G2 6 -47.94048 G3 14 59.76284 G4 31 -100.34191 G5 35 76.29409 G6 37 -125.96848 [Variable interval data] W M T W M T Infinity Infinity Infinity Short distance Short distance Short distance f 71.47903 135 196.00001 ― ― ― β ― ― ― -0.07596 -0.13523 -0.18897 D5 1.6 36.65047 53.37203 1.6 36.65047 53.37203 D13 50.34136 17.30611 1.5894 50.34136 17.30611 1.5894 D30 4.89104 5.69832 3.75297 5.82603 9.72514 12.39738 D34 30.18447 22.82939 30.17853 25.97701 9.1382 2.51645 D36 14.96274 19.49533 13.08668 18.23522 29.1597 32.10436 [Condition formula corresponding values] Condition formula (1) f3 / (-fE)=0.47 Condition formula (2) f1 / (-fE)=1.15 Condition formula (3) f2 / fE=0.38 Condition formula (4) f1 / (-f2)=3.03 Condition formula (5) f1 / f3=2.43 Condition formula (6) f1 / f4=-1.45 Condition formula (7) (-fF1) / fF2=1.32 Condition formula (8) νdP=27.35 Condition formula (9) ndP+(0.01425×νdP)=2.0536 Condition formula (10) θgFP+(0.00316×νdP)=0.7183 Conditional expression (11): 2ωw = 34.09° Conditional expression (12): 2ωt = 12.31° Conditional expression (13): BFw / fw = 0.44

[0175] FIG. 14(A), FIG. 14(B), and FIG. 14(C) are aberration diagrams in the wide-angle end state, intermediate focal length state, and telephoto end state of the zoom optical system according to the seventh embodiment, respectively. From each aberration diagram, it can be seen that the zoom optical system according to the seventh embodiment has well-corrected aberrations and excellent imaging performance.

[0176] According to each embodiment, a zoom optical system with well-corrected aberrations such as spherical aberration can be realized.

[0177] Here, each of the above embodiments shows a specific example of the present invention, and the present invention is not limited thereto.

[0178] Note that the following content can be appropriately adopted as long as it does not impair the optical performance of the zoom optical system according to the present embodiment.

[0179] As numerical examples of the zoom optical system, those having 6 groups, 7 groups, 8 groups, 9 groups, and 10 groups are shown, but the present application is not limited thereto, and a zoom optical system having other group configurations (for example, 5 groups, 11 groups, etc.) can also be configured. Specifically, a configuration in which a lens or a lens group is added to the most object side or the most image side of the zoom optical system may be used. Note that the lens group indicates a portion having at least one lens separated by an air interval that changes during zooming.

[0180] The lens surface may be formed as a spherical surface or a flat surface, or may be formed as an aspherical surface. When the lens surface is a spherical surface or a flat surface, it is preferable because lens processing and assembly adjustment are facilitated, and deterioration of optical performance due to errors in processing and assembly adjustment can be prevented. Also, it is preferable because deterioration of the rendering performance is small even when the image plane is displaced.

[0181] When the lens surface is an aspherical surface, the aspherical surface may be any of an aspherical surface formed by grinding, a glass mold aspherical surface formed by molding glass into an aspherical shape, and a composite aspherical surface formed by forming a resin on the surface of glass into an aspherical shape. Further, the lens surface may be a diffractive surface, and the lens may be a refractive index distribution type lens (GRIN lens) or a plastic lens.

[0182] Each lens surface may be provided with an antireflection film having a high transmittance in a wide wavelength range in order to reduce flare and ghost and achieve high-contrast optical performance. Thereby, flare and ghost can be reduced, and high-contrast optical performance can be achieved.

Explanation of Reference Numerals

[0183] G1 First lens group G2 Second lens group G3 Third lens group GR Subsequent lens group I Image plane S Aperture stop

Claims

1. It consists of a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a subsequent lens group, arranged in order from the object side, During zooming, the interval between adjacent lens groups changes, and the first lens group is fixed with respect to the image plane, During zooming from the wide-angle end state to the telephoto end state, the third lens group moves, The subsequent lens group consists of a fourth lens group having a positive refractive power, a fifth lens group having a negative refractive power, a sixth lens group having a positive refractive power, and a final lens group, During focusing, the fifth lens group and the sixth lens group move, A zoom optical system that satisfies the following conditional expressions. 0.30 < f3 / (-fE) < 3.50 2.90 < f1 / (-f2) < 5.00 However, f3: The focal length of the third lens group fE: The focal length of the final lens group f1: The focal length of the first lens group f2: The focal length of the second lens group

2. The zoom optical system according to Claim 1, which satisfies the following conditional expressions. 1.61 ≦ f1 / f4 < 4.00 However, f4: The focal length of the fourth lens group

3. The zoom optical system according to Claim 1 or 2, which satisfies the following conditional expressions. -10.00 < f1 / (-fE) < 3.50

4. The zoom optical system according to any one of Claims 1 to 3, which satisfies the following conditional expressions. -10.00 < f2 / fE < 1.50

5. The zoom optical system according to any one of Claims 1 to 4, which satisfies the following conditional expressions. 1.50 < f1 / (-f2) < 5.00

6. The zoom optical system according to any one of Claims 1 to 5, which satisfies the following conditional expressions. -2.00 < f1 / f4 < 4.00 However, f4: The focal length of the fourth lens group

7. The zoom optical system according to any one of Claims 1 to 6, wherein the second lens group has a positive lens that satisfies the following conditional expressions. 18.0 < νdP < 35.0 1.83 < ndP + (0.01425 × νdP) < 2.12 0.702 < θgFP + (0.00316 × νdP) However, νdP: The Abbe number of the positive lens based on the d line ndP: The refractive index of the positive lens with respect to the d line θgFP: The partial dispersion ratio of the positive lens. When the refractive index of the positive lens with respect to the g line is ngP, the refractive index with respect to the F line is nFP, and the refractive index with respect to the C line is nCP, it is defined by the following formula θgFP = (ngP - nFP) / (nFP - nCP) Note that the Abbe number νdP based on the d-line of the positive lens is defined by the following formula νdP = (ndP - 1) / (nFP - nCP) **Claim 8** An optical apparatus configured by mounting a zoom optical system according to any one of Claims 1 to 7.

Images