JP2022103302A - Zoom optical system and optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom optical system which is well corrected for various aberrations including spherical aberration.

SOLUTION: A zoom optical system ZL provided herein comprises 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 such that a distance between each pair of adjacent lens groups change while the first lens group G1 is stationary relative to the image plane when zooming, and the third lens group G3 moves when zooming from the wide-angle end to the telephoto end. The succeeding lens group GR comprises a fourth lens group G4, fifth lens group G5, and a final lens group located on the most image side. The zoom optical system satisfies the following conditional expressions: -10.00<f3/(-fE)<3.50, 1.20<f1/f4<2.30, where f3 represents a focal length of the third lens group G3, fE represents a focal length of the final lens group, f1 represents a focal length of the first lens group G1, and f4 represents a focal length of the fourth lens group G4.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a variable magnification optical system and an optical device using the same.

Conventionally, variable magnification optical systems suitable for photographic cameras, electronic still cameras, video cameras and the like have been proposed (see, for example, Patent Document 1). In the variable magnification optical system, it is required to satisfactorily correct the aberration.

Japanese Unexamined Patent Publication No. 2016-139125

The variable magnification optical system according to the first aspect has a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a first lens group having a positive refractive power arranged in order from the object side. It has three lens groups and a succeeding lens group, and the distance between adjacent lens groups changes during scaling, the first lens group is fixed to the image plane, and the wide-angle end state to the telephoto end. When the magnification is changed to the state, the third lens group moves, and the succeeding lens group includes the fourth lens group and the fifth lens group arranged side by side on the image side of the fourth lens group. It has a final lens group arranged on the image side most, and satisfies the following conditional expression.
-10.00 <f3 / (-fE) <3.50
1.20 <f1 / f4 <2.30
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 f4: the focal length of the fourth lens group

The variable magnification optical system according to the second aspect includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a second lens group having a positive refractive power, which are arranged in order from the object side. It has three lens groups and a succeeding lens group, and the distance between adjacent lens groups changes during scaling, the first lens group is fixed to the image plane, and the wide-angle end state to the telephoto end. When the magnification is changed to the state, the third lens group moves, and the succeeding lens group includes the fourth lens group and the fifth lens group arranged side by side on the image side of the fourth lens group. It has a final lens group arranged on the image side most, and satisfies the following conditional expression.
-0.50 <f3 / (-fE) <3.50
-2.00 <f1 / f4 <2.30
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 f4: the focal length of the fourth lens group

The optical device according to the third aspect is configured by mounting the above-mentioned variable magnification optical system.

It is a figure which shows the movement of the lens when the variable magnification optical system which concerns on 1st Embodiment changes from a wide-angle end state to a telephoto end state. 2 (A), 2 (B), and 2 (C) are aberration diagrams in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the first embodiment, respectively. .. It is a figure which shows the movement of the lens when the variable magnification optical system which concerns on 2nd Example changes from a wide-angle end state to a telephoto end state. 4 (A), 4 (B), and 4 (C) are aberration diagrams in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the second embodiment, respectively. .. It is a figure which shows the movement of the lens when the variable magnification optical system which concerns on 3rd Example changes from a wide-angle end state to a telephoto end state. 6 (A), 6 (B), and 6 (C) are aberration diagrams in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the third embodiment, respectively. .. It is a figure which shows the movement of the lens when the variable magnification optical system which concerns on 4th Embodiment changes from a wide-angle end state to a telephoto end state. 8 (A), 8 (B), and 8 (C) are aberration diagrams in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the fourth embodiment, respectively. .. It is a figure which shows the movement of the lens when the variable magnification optical system which concerns on 5th Embodiment changes from a wide-angle end state to a telephoto end state. 10 (A), 10 (B), and 10 (C) are aberration diagrams in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the fifth embodiment, respectively. .. It is a figure which shows the movement of the lens when the variable magnification optical system which concerns on 6th Embodiment changes from a wide-angle end state to a telephoto end state. 12 (A), 12 (B), and 12 (C) are aberration diagrams in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the sixth embodiment, respectively. .. It is a figure which shows the movement of the lens when the variable magnification optical system which concerns on 7th Embodiment changes from a wide-angle end state to a telephoto end state. 14 (A), 14 (B), and 14 (C) are aberration diagrams in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the seventh embodiment, respectively. .. It is a figure which shows the structure of the camera provided with the variable magnification optical system which concerns on this embodiment. It is a flowchart which shows the manufacturing method of the variable magnification optical system which concerns on this embodiment.

Hereinafter, the variable magnification optical system and the optical device according to this embodiment will be described with reference to the drawings. First, a camera (optical device) provided with a variable magnification optical system according to this embodiment will be described with reference to FIG. As shown in FIG. 15, the camera 1 is a digital camera provided with a variable magnification optical system according to the present embodiment as a photographing lens 2. In the camera 1, the light from an object (subject) (not shown) is collected by the photographing lens 2 and reaches the image pickup element 3. As a result, the light from the subject is captured by the image sensor 3 and recorded as a subject image in a memory (not shown). In this way, the photographer can shoot the subject with the camera 1. This camera may be a mirrorless camera or a single-lens reflex type camera having a quick return mirror.

Next, the variable magnification optical system (shooting lens) according to this embodiment will be described. As shown in FIG. 1, the variable magnification optical system ZL (1) as an example of the variable magnification optical system (zoom lens) ZL according to the present embodiment is the first having a positive refractive power arranged in order from the object side. It has a lens group G1, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, and a succeeding lens group GR. At the time of scaling, the distance between adjacent lens groups changes. At the time of scaling, the first lens group G1 is fixed to the image plane. When scaling 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 succeeding lens group GR has a final lens group arranged on the image side most.

Under the above configuration, the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (1).

-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

According to the present embodiment, it is possible to obtain a variable magnification optical system in which various aberrations such as spherical aberration are satisfactorily corrected, and an optical device provided with the variable magnification optical system. The variable-magnification optical system ZL according to the present embodiment may be the variable-magnification optical system ZL (2) shown in FIG. 3, the variable-magnification optical system ZL (3) shown in FIG. 5, or the variable-magnification optical system shown in FIG. 7. It may be ZL (4). Further, the variable magnification optical system ZL according to the present embodiment may be the variable magnification optical system ZL (5) shown in FIG. 9, the variable magnification optical system ZL (6) shown in FIG. 11, or the variable magnification optical system ZL (6) shown in FIG. The optical system ZL (7) may be used.

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 equation (1), spherical aberration, coma aberration, and curvature of field can be satisfactorily corrected.

When the corresponding value of the conditional expression (1) exceeds the upper limit value, the refractive power of the third lens group G3 becomes weak, and it becomes difficult to satisfactorily correct the spherical aberration and the coma aberration. Further, since the negative refractive power of the final lens group becomes strong, it becomes difficult to satisfactorily correct coma aberration and curvature of field. By setting the upper limit value of the conditional expression (1) to 3.40, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (1) is set to 3.30, 3.20, 3.10, 3.00, 2.90, 2.85, 2. It may be set to .75, 2.70, and further 2.65.

When the corresponding value of the conditional expression (1) is less than the lower limit value, the refractive power of the third lens group G3 becomes strong, so that it becomes difficult to satisfactorily correct the spherical aberration and the coma aberration. Further, since the refractive power of the final lens group is weakened, it becomes difficult to satisfactorily correct coma aberration and curvature of field. By setting the lower limit of the conditional expression (1) to −8.00, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (1) is set to -5.00, -3.00, -1.00, -0.50, 0.30, 0. It may be set to .40 and further 0.45.

It is desirable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (2).

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

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

When the corresponding value of the conditional expression (2) exceeds the upper limit value, the refractive power of the first lens group G1 becomes weak, so that the spherical aberration near the telephoto end state and the curvature of field near the wide-angle end state are good. It becomes difficult to correct to. Further, since the negative refractive power of the final lens group becomes strong, it becomes difficult to satisfactorily correct coma aberration and curvature of field. By setting the upper limit value of the conditional expression (2) to 3.40, the effect of this embodiment can be further ensured. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (2) is set to 3.30, 3.20, 3.10, 3.00, 2.95, 2.90, 2. It may be set to .85, 2.80, and further 2.75.

When the corresponding value of the conditional expression (2) is less than the lower limit value, the refractive power of the first lens group G1 becomes stronger, so that the spherical aberration on the side near the telephoto end state and the curvature of field near the wide-angle end state are good. It becomes difficult to correct to. Further, since the refractive power of the final lens group is weakened, it becomes difficult to satisfactorily correct coma aberration and curvature of field. By setting the lower limit of the conditional expression (2) to −8.00, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (2) is set to -5.00, -3.00, -1.00, -0.50, 0.30, 0. It may be set to .50, 0.75, 0.90, and further 1.00.

It is desirable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (3).

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

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

When the corresponding value of the conditional expression (3) exceeds the upper limit value, the refractive power of the second lens group G2 becomes weak, and it becomes difficult to satisfactorily correct the spherical aberration and the coma aberration. Further, since the negative refractive power of the final lens group becomes strong, it becomes difficult to satisfactorily correct coma aberration and curvature of field. By setting the upper limit value of the conditional expression (3) to 1.40, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (3) is set to 1.30, 1.20, 1.10, 1.00, 0.90, and further 0.80. It may be set.

When the corresponding value of the conditional expression (3) is less than the lower limit value, the refractive power of the second lens group G2 becomes strong, so that it becomes difficult to satisfactorily correct the spherical aberration and the coma aberration. Further, since the refractive power of the final lens group is weakened, it becomes difficult to satisfactorily correct coma aberration and curvature of field. By setting the lower limit of the conditional expression (3) to −8.00, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (3) is set to -5.00, -3.00, -1.00, -0.50, 0.10, 0. It may be set to .20, 0.30, and further 0.35.

It is desirable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (4).

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

The conditional expression (4) defines the ratio between the focal length of the first lens group G1 and the focal length of the second lens group G2. By satisfying the conditional expression (4), coma aberration and spherical aberration can be satisfactorily corrected, and a scaling ratio satisfying the present embodiment can be secured.

When the corresponding value of the conditional equation (4) exceeds the upper limit value, the refractive power of the second lens group G2 becomes strong, and it becomes difficult to correct coma aberration and spherical aberration. By setting the upper limit value of the conditional expression (4) to 4.80, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (4) is set to 4.50, 4.3.
It may be set to 0, 4.00, 3.90, 3.80, and further 3.75.

When the corresponding value of the conditional equation (4) is less than the lower limit value, the refractive power of the first lens group G1 becomes strong, and it becomes difficult to correct coma aberration and spherical aberration. By setting the lower limit of the conditional expression (4) to 1.75, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (4) is set to 1.90, 2.00, 2.25, 2.40, 2.50, 2.70, 2 It may be set to .80, 2.90, and further 3.00.

It is desirable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (5).

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

The conditional expression (5) defines the ratio between the focal length of the first lens group G1 and the focal length of the third lens group G3. By satisfying the conditional expression (5), spherical aberration and coma can be satisfactorily corrected.

When the corresponding value of the conditional expression (5) exceeds the upper limit value, the refractive power of the third lens group G3 becomes strong, so that it becomes difficult to correct spherical aberration and coma. By setting the upper limit value of the conditional expression (5) to 2.45, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (5) is set to 2.40, 2.20, 2.00, 1.90, 1.80, 1.70, 1 It may be set to .60 and further 1.50.

When the corresponding value of the conditional expression (5) is less than the lower limit value, the refractive power of the first lens group G1 becomes strong, so that it becomes difficult to correct spherical aberration and coma. By setting the lower limit of the conditional expression (5) to 0.82, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (5) is set to 0.85, 0.87, 0.90, 0.92, 0.95, 0.98, and further. It may be set to 1.00.

In the variable magnification optical system ZL according to the present embodiment, the succeeding lens group GR has a fourth lens group G4, and it is desirable that the following conditional expression (6) is satisfied.

-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

The conditional expression (6) defines the ratio between the focal length of the first lens group G1 and the focal length of the fourth lens group G4. By satisfying the conditional expression (6), spherical aberration and coma can be satisfactorily corrected.

When the corresponding value of the conditional expression (6) exceeds the upper limit value, the refractive power of the fourth lens group G4 becomes strong, so that it becomes difficult to correct spherical aberration and coma. By setting the upper limit value of the conditional expression (6) to 3.80, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (6) is set to 3.60, 3.50, 3.20, 3.00, 2.80, 2.60, 2 It may be set to .50, 2.40, and further 2.30.

When the corresponding value of the conditional equation (6) is less than the lower limit value, the refractive power of the first lens group G1 becomes strong, so that it becomes difficult to correct spherical aberration and coma aberration. By setting the lower limit of the conditional expression (6) to -1.50, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (6) is set to 0.50, 0.80, 1.00, 1.20, 1.40, 1.50, and further. It may be set to 1.55.

In the variable magnification optical system ZL according to the present embodiment, it is desirable that the final lens group is fixed to the image plane at the time of magnification change. As a result, the drive mechanism of the lens group of the present embodiment can be simplified and the lens barrel can be miniaturized.

In the variable magnification optical system ZL according to the present embodiment, at least one lens group among the lens groups arranged on the image side of the third lens group G3 is fixed to the image plane at the time of magnification change. Is desirable. This is preferable because the drive mechanism of the lens group of the present embodiment can be simplified, the lens barrel can be miniaturized, and the aberration fluctuation at the time of scaling can be reduced.

In the variable magnification optical system ZL according to the present embodiment, the succeeding lens group GR is the first focusing lens group having a negative refractive power that moves in focusing, which is arranged in order from the object side, and in focusing. It is desirable to have a second focusing lens group having a positive refractive power that moves to, and satisfy the following conditional equation (7).

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

The conditional expression (7) defines the ratio between the focal length of the first focusing lens group and the focal length of the second focusing lens group. By satisfying the conditional equation (7), it is possible to suppress fluctuations in various aberrations such as spherical aberration when focusing from an infinity object to a short-distance object.

When the corresponding value of the conditional expression (7) exceeds the upper limit value, the refractive power of the second focusing lens group becomes strong, so that it becomes difficult to suppress fluctuations of various aberrations such as spherical aberration during focusing. Become. By setting the upper limit value of the conditional expression (7) to 4.75, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (7) is set to 4.50, 4.25, 4.00, 3.75, 3.50, 3.25, 3 It may be set to 0.00, 2.75, 2.50, 2.25, and further 2.00.

When the corresponding value of the conditional expression (7) is less than the lower limit value, the negative refractive power of the first focusing lens group becomes stronger, so that it is possible to suppress fluctuations in various aberrations such as spherical aberration during focusing. It will be difficult. By setting the lower limit value of the conditional expression (7) to 0.85, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (7) is set to 0.90, 1.00, 1.10, 1.20, 1.25, 1.28, and further. It may be set to 1.30.

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

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 of the positive lens with respect to the d-line θgFP: Partial dispersion ratio of the positive lens, and the refractive index of the positive lens with respect to the g-line is ng.
When P is defined, the refractive index of the positive lens with respect to the F line is nFP, and the refractive index of the positive lens with respect to the C line is nCP, θgFP = (ngP-nFP) / (nFP-nCP) defined by the following equation.
The Abbe number νdP with respect to the d-line of the positive lens is νdP = (ndP-1) / (nFP-nCP) defined by the following equation.

The conditional expression (8) defines an appropriate range of Abbe numbers with respect to the d-line of the positive lens in the second lens group G2. By satisfying the conditional equation (8), it is possible to satisfactorily correct reference aberrations such as spherical aberration and coma, and correct primary chromatic aberration (achromaticization).

If the corresponding value of the conditional expression (8) exceeds the upper limit value, it becomes difficult to correct the axial chromatic aberration, which is not preferable. By setting the upper limit value of the conditional expression (8) to 32.5, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit value of the conditional expression (8) to 31.5.

If the corresponding value of the conditional expression (8) is less than the lower limit value, it becomes difficult to correct the axial chromatic aberration, which is not preferable. By setting the lower limit of the conditional expression (8) to 20.00, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (8) is set to 22.00, 23.00, 23.50, 24.00, 25.00, and further 26.00. It is preferable to do so.

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

If the corresponding value of the conditional expression (9) deviates from the above range, for example, the Petzval sum becomes small, which makes it difficult to correct the curvature of field, which is not preferable. By setting the upper limit value of the conditional expression (9) to 2.10, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, it is preferable that the upper limit of the conditional expression (9) is 2.08 and further 2.06. Further, by setting the lower limit value of the conditional expression (9) to 1.84, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit value of the conditional expression (9) to 1.85.

The conditional expression (10) appropriately defines the anomalous dispersibility of the positive lens in the second lens group G2. By satisfying the conditional expression (10), in the correction of chromatic aberration, the secondary spectrum can be satisfactorily corrected in addition to the primary achromaticity.

When the corresponding value of the conditional expression (10) is less than the lower limit value, the anomalous dispersibility of the positive lens becomes small, and it becomes difficult to correct the chromatic aberration. By setting the lower limit value of the conditional expression (10) to 0.704, the effect of the present embodiment can be further ensured. In order to further ensure the effect of the present embodiment, it is preferable that the lower limit values of the conditional expression (10) are 0.708, 0.710, and further 0.715.

It is desirable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (11).

25.00 ° <2ωw <50.00 ° ... (11)
However, 2ωw: the total angle of view of the variable magnification optical system ZL in the wide-angle end state.

The conditional expression (11) defines the total angle of view of the variable magnification optical system ZL in the wide-angle end state. By satisfying the conditional equation (11), various aberrations such as coma aberration, distortion, and curvature of field can be satisfactorily corrected while having a wide angle of view satisfying the present embodiment. By setting the lower limit value of the conditional expression (11) to 27.00 °, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (11) may be set to 29.00 °, 30.00 °, 32.00 °, and further 33.00 °. good. Further, by setting the upper limit value of the conditional expression (11) to 48.00 °, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (11) is set to 45.00 °, 42.00 °, 40.00 °, 38.00 °, 36.00 °, Further, it may be set to 35.00 °.

It is desirable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (12).

5.00 ° <2ωt <20.00 ° ・ ・ ・ (12)
However, 2ωt: the total angle of view of the variable magnification optical system ZL in the telephoto end state.

The conditional expression (12) defines the total angle of view of the variable magnification optical system ZL in the telephoto end state. By satisfying the conditional equation (12), various aberrations such as coma aberration, distortion, and curvature of field can be satisfactorily corrected. By setting the upper limit value of the conditional expression (12) to 18.00 °, the effect of this embodiment can be further ensured. In order to further ensure the effect of the present embodiment, the upper limit of the conditional expression (12) may be set to 16.00 °, 15.00 °, 14.00 °, and further 13.00 °. good. On the other hand, by setting the lower limit value of the conditional expression (12) to 7.00 °, the effect of the present embodiment can be further ensured. In order to further ensure the effect of the present embodiment, the lower limit of the conditional expression (12) may be set to 8.00 °, 10.00 °, 11.00 °, and further 12.00 °. good.

It is desirable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (13).

0.20 <BFw / fw <0.85 ... (13)
However, BFw: the back focus of the variable magnification optical system ZL in the wide-angle end state fw: the focal length of the variable magnification optical system ZL in the wide-angle end state.

The conditional equation (13) defines the ratio between the back focus of the variable magnification optical system ZL in the wide-angle end state and the focal length of the variable magnification optical system ZL in the wide-angle end state. By satisfying the conditional expression (13), various aberrations such as coma aberration in the wide-angle end state can be satisfactorily corrected.

When the corresponding value of the conditional equation (13) exceeds the upper limit value, the back focus becomes too large with respect to the focal length of the variable magnification optical system ZL in the wide-angle end state, so that various aberrations including coma aberration in the wide-angle end state Becomes difficult to correct. By setting the upper limit value of the conditional expression (13) to 0.80, the effect of the present embodiment can be further ensured. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (13) may be set to 0.75, 0.70, 0.65, 0.60, and further 0.55. good.

When the corresponding value of the conditional equation (13) is less than the lower limit, the back focus becomes too small with respect to the focal length of the variable magnification optical system ZL in the wide-angle end state, so that various aberrations including coma aberration in the wide-angle end state Becomes difficult to correct. In addition, it becomes difficult to arrange the mechanical member of the lens barrel. By setting the lower limit value of the conditional expression (13) to 0.25, the effect of the present embodiment can be further ensured. In order to further ensure the effect of the present embodiment, the lower limit of the conditional expression (13) may be set to 0.30, 0.35, 0.40, and further 0.42.

Subsequently, with reference to FIG. 16, the manufacturing method of the variable magnification optical system ZL according to the present 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. And are arranged (step ST1). Then, it is configured so that the distance between adjacent lens groups changes at the time of scaling (step ST2). At the time of scaling, the first lens group G1 is fixed with respect to the image plane. When scaling 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. Further, the final lens group is arranged on the most image side of the succeeding 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 variable magnification optical system in which various aberrations such as spherical aberration are satisfactorily corrected.

Hereinafter, the variable magnification optical system ZL according to the embodiment of the present embodiment will be described with reference to the drawings. In FIGS. 1, 3, 5, 7, 7, 9, 11, and 13, the variable magnification optical system ZL {ZL (1) to ZL (7)} according to the first to seventh embodiments has a wide-angle end. It is a figure which shows the movement of a lens at the time of changing from a state to a telephoto end state. In each figure, the moving direction along the optical axis of the lens group that moves when the magnification is changed from the wide-angle end state to the telephoto end state is indicated by an arrow. Furthermore, the direction of movement when the focusing lens group focuses on a short-distance object from infinity is indicated by an arrow together with the letters "focusing".

In these figures (FIG. 1, FIG. 3, FIG. 5, FIG. 7, FIG. 9, FIG. 11, FIG. 13), each lens group is represented by a combination of reference numerals G and numbers, and each lens is designated by a combination of reference numerals L and numbers. Each is represented. In this case, in order to prevent the types and numbers of codes and numbers from becoming large and complicated, the lens group and the like are represented by independently using combinations of codes and numbers for each embodiment. Therefore, even if the same combination of reference numerals and numbers is used between the examples, it does not mean that they have the same configuration.

Tables 1 to 7 are shown below, of which Table 1 is the first embodiment, Table 2 is the second embodiment, Table 3 is the third embodiment, Table 4 is the fourth embodiment, and Table 5 is the first embodiment. 5 Examples, Table 6 is a table showing each specification data in the 6th Example, and Table 7 is a table showing each specification data in the 7th Example. In each embodiment, the d-line (wavelength λ = 587.6 nm) and the g-line (wavelength λ = 435.8 nm) are selected as the calculation targets of the aberration characteristics.

In the [Overall specifications] table, FNO is the F number, 2ω is the angle of view (unit is ° (degrees), and ω is the half angle of view), and Y is the image height. TL indicates the distance from the frontmost surface of the lens to the final surface of the lens on the optical axis at infinity, plus BF, and BF is the image from the final surface of the lens on the optical axis at infinity. The air conversion distance (back focus) to the surface I is shown. These values are shown for each of the wide-angle end (W), intermediate focal length (M), and telephoto end (T) in each variable magnification state. Further, in the table of [Overall specifications], θgFP indicates the partial dispersion ratio of the positive lens in the second lens group.

In the [Lens Specifications] table, the plane numbers indicate the order of the optical planes from the object side along the traveling direction of the light beam, and R is the radius of curvature of each optical plane (the plane whose center of curvature is located on the image side). (Positive value), D is the distance on the optical axis from each optical surface to the next optical surface (or image surface), nd is the refractive index of the material of the optical member with respect to the d line, and νd is optical. The Abbe number and θgF based on the d-line of the material of the member indicate the partial dispersion ratio of the material of the optical member. “∞” of the radius of curvature indicates a plane or an aperture, and (aperture S) indicates an aperture stop. The description of the refractive index nd of air = 1.00000 is omitted. When the lens surface is an aspherical surface, the surface number is marked with * and the radius of curvature R indicates the near-axis radius of curvature.

The refractive index of the material of the optical member with respect to the g line (wavelength λ = 435.8 nm) is ng, the refractive index of the material of the optical member with respect to the F line (wavelength λ = 486.1 nm) is nF, and the refractive index of the material of the optical member is C. Let nC be the refractive index for the 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 equation (A).

θgF = (ng-nF) / (nF-nC) ... (A)

In the table of [Aspherical surface data], the shape of the aspherical surface shown in [Lens specifications] is shown by the following equation (B). X (y) is the distance (zag amount) along the optical axis direction from the tangent plane at the apex of the aspherical surface to the position on the aspherical surface at the height y, and R is the radius of curvature (near axis radius of curvature) of the reference spherical surface. , Kappa is the conical constant, and Ai is the i-th order aspherical coefficient. "E-n" indicates " ^{x10 -n} ". For example, 1.234E-05 = 1.234 × 10 ^-5 . The second-order aspherical coefficient A2 is 0, and the description thereof is omitted.

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)

The table of [lens group data] shows the start surface (the surface closest to the object) and the focal length of each lens group.

The table of [Variable Interval Data] shows the surface spacing with the surface number in which the surface spacing is "variable" in the table showing [lens specifications]. Here, the plane spacings at the wide-angle end (W), the intermediate focal length (M), and the telephoto end (T) are shown for each of the focused states at infinity and short distance. In [variable interval data], f indicates the focal length of the entire lens system, and β indicates the shooting magnification.

The table of [Conditional expression corresponding values] shows the values corresponding to each conditional expression.

Hereinafter, in all the specification values, "mm" is generally used for the focal length f, the radius of curvature R, the plane spacing D, other lengths, etc., unless otherwise specified, but the optical system is expanded proportionally. Alternatively, it is not limited to this because the same optical performance can be obtained even if the proportional reduction is performed.

The description of the table so far is common to all the examples, and the duplicate description below is omitted.

(First Example)
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 a lens when the variable magnification optical system according to the first embodiment changes from a wide-angle end state to a telephoto end state. The variable magnification optical system ZL (1) according to the first embodiment has a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a positive lens group G2 arranged in order from the object side. 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, and a sixth lens group G6 having a positive refractive power. It is composed of 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 scaling 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 are separately shown in FIG. It moves in the direction indicated by the arrow, and the distance between adjacent lens groups changes. At the time of scaling, 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 consisting of the 4th lens group G4, the 5th lens group G5, the 6th lens group G6, the 7th lens group G7, the 8th lens group G8, and the 9th lens group G9 is the subsequent lens group. Corresponds to GR. The symbol (+) or (−) attached to each lens group symbol indicates the refractive power of each lens group, and this also applies to all the following examples.

The first lens group G1 is a junction lens of a negative meniscus lens L11 having a convex surface facing the object side and a plano-convex positive lens L12 having a convex surface facing the object side, which are arranged in order from the object side, and a convex surface toward the object side. It is composed of a positive meniscus lens L13 facing the lens.

The second lens group G2 includes a negative meniscus lens L21 having a convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L23 having a convex surface facing the object side, which are arranged in order from the object side. It is composed of a concave negative lens L24.

The third lens group G3 is composed of a positive meniscus lens L31 having a convex surface facing the object side.

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

The fifth lens group G5 is composed of a junction lens of a biconcave negative lens L51 and a biconvex positive lens L52. The aperture stop S is arranged on the most object side of the fifth lens group G5, and moves together with the fifth lens group G5 at the time of scaling.

The sixth lens group G6 is a junction lens of a negative meniscus lens L61 having a convex surface facing the object side, a biconvex positive lens L62, and a negative meniscus lens L63 having 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 positive lens L62 has an aspherical lens surface on the object side.

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

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

The ninth lens group G9 is composed of a negative meniscus lens L91 having a concave surface facing the object side and a negative meniscus lens L92 having a concave surface facing the object side, which are arranged in order from the object side. The negative meniscus lens L91 has an aspherical lens surface on the object side. The 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.

In this embodiment, the 7th lens group G7 is moved to the image plane I side, and the 8th lens group G8 is moved to the object side, thereby moving from a long-distance object to a short-distance object (from an infinite distance object to a finite-distance object). Is focused. That is, the 7th lens group G7 corresponds to the 1st in-focus lens group, and the 8th lens group G8 corresponds to the 2nd in-focus lens group.

Table 1 below lists the values of the specifications of the variable magnification optical system according to the first embodiment.

(Table 1)
[Overall specifications]
Magnification ratio 2.74
θgFP = 0.6319
WMT
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 RD 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]
Side 26 κ = 0.00, A4 = -2.00E-06, A6 = 8.31E-10
A8 = -6.83E-12, A10 = 2.63E-14, A12 = -3.55E-17
Surface 37 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]
Focal length of group origin
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
Point at infinity Point at infinity Point at infinity Short distance Short distance Short 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 expression correspondence 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

2 (A), 2 (B), and 2 (C) are aberration diagrams in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the first embodiment, respectively. .. In each aberration diagram, FNO indicates an F number and Y indicates an image height. The spherical aberration diagram shows the value of the F number corresponding to the maximum aperture, the astigmatism diagram and the distortion diagram show the maximum image height, and the transverse aberration diagram shows the value of each image height. 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 shows the sagittal image plane and the broken line shows the meridional image plane. In the aberration diagrams of each embodiment shown below, the same reference numerals as those of the present embodiment are used, and duplicate description is omitted.

From each aberration diagram, it can be seen that the variable magnification optical system according to the first embodiment has various aberrations corrected well and has excellent imaging performance.

(Second Example)
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 variable magnification optical system according to the second embodiment changes from the wide-angle end state to the telephoto end state. The variable magnification optical system ZL (2) according to the second embodiment has a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a positive lens group G2 arranged in order from the object side. 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, and a sixth lens group G6 having a positive refractive power. , A seventh lens group G7 having a negative refractive power. When scaling 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 are separately oriented in the directions indicated by the arrows in FIG. It moves and the distance between adjacent lens groups changes. At the time of scaling, 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 including the fourth lens group G4, the fifth lens group G5, the sixth lens group G6, and the seventh lens group G7 corresponds to the succeeding lens group GR.

The first lens group G1 is a junction lens of a negative meniscus lens L11 having 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 having a convex surface facing the object side. It is composed of and.

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

The third lens group G3 is composed of a positive meniscus lens L31 having a convex surface facing the object side.

The fourth lens group G4 includes a positive meniscus lens L41 having a convex surface facing the object side, a positive meniscus lens L42 having a convex surface facing the object side, and a biconcave negative lens L43 and biconvex lenses arranged in order from the object side. A junction lens with a positive lens L44 having a shape, a negative meniscus lens L45 with a convex surface facing the object side, a junction lens between a biconvex positive lens L46 and a negative meniscus lens L47 with a concave surface facing the object side, and an object. It is composed of a positive meniscus lens L48 with a convex surface facing to the side. An aperture diaphragm S is arranged 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 at the time of scaling. The positive lens L46 has an aspherical lens surface on the object side.

The fifth lens group G5 is composed of a positive meniscus lens L51 having a concave surface facing the object side and a negative lens L52 having both concave shapes arranged in order from the object side.

The sixth lens group G6 is composed of a biconvex positive lens L61.

The seventh lens group G7 is composed of a negative lens L71 having a biconcave shape. The negative lens L71 has an aspherical lens surface on the object side. The image plane I is arranged on the image side of the seventh lens group G7. That is, the seventh lens group G7 corresponds to the final lens group.

In this embodiment, the fifth lens group G5 is moved to the image plane I side, and the sixth lens group G6 is moved to the object side, thereby moving from a long-distance object to a short-distance object (from an infinite distance object to a finite-distance object). Is focused. That is, the fifth lens group G5 corresponds to the first in-focus lens group, and the sixth lens group G6 corresponds to the second in-focus lens group.

Table 2 below lists the values of the specifications of the variable magnification optical system according to the second embodiment.

(Table 2)
[Overall specifications]
Magnification ratio 2.74
θgFP = 0.6319
WMT
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 RD 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]
Surface 26 κ = 0.00, A4 = -2.17E-06, A6 = 1.23E-09
A8 = -8.20E-12, A10 = 2.53E-14, A12 = -2.96E-17
Side 37 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]
Focal length of group origin
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
Point at infinity Point at infinity Point at infinity Short distance Short distance Short 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 expression correspondence 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

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

(Third Example)
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 the lens when the variable magnification optical system according to the third embodiment changes from the wide-angle end state to the telephoto end state. The variable magnification optical system ZL (3) according to the third embodiment has a first lens group G1 having a positive refractive force, a second lens group G2 having a negative refractive force, and a positive lens group G2 arranged in order from the object side. 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, and a sixth lens group G6 having a positive refractive power. , The 7th lens group G7 having a negative refractive force, the 8th lens group G8 having a positive refractive force, the 9th lens group G9 having a positive refractive force, and the 10th lens group having a negative refractive force. It is composed of G10. When scaling 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 moves separately in the direction indicated by the arrow in FIG. 5, and the distance between the adjacent lens groups changes. At the time of scaling, 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. It consists of a 4th lens group G4, a 5th lens group G5, a 6th lens group G6, a 7th lens group G7, an 8th lens group G8, a 9th lens group G9, and a 10th lens group G10. The lens group corresponds to the subsequent lens group GR.

The first lens group G1 is a junction lens of a negative meniscus lens L11 having 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 having a convex surface facing the object side. It is composed of and.

The second lens group G2 includes a negative meniscus lens L21 having a convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L23 having a convex surface facing the object side, which are arranged in order from the object side. It is composed of a concave negative lens L24.

The third lens group G3 is composed of a positive meniscus lens L31 having a convex surface facing the object side.

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

The fifth lens group G5 is composed of a junction lens of a biconcave negative lens L51 and a biconvex positive lens L52. The aperture stop S is arranged on the most object side of the fifth lens group G5, and moves together with the fifth lens group G5 at the time of scaling.

The sixth lens group G6 is a junction lens of a negative meniscus lens L61 having a convex surface facing the object side, a biconvex positive lens L62, and a negative meniscus lens L63 having 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 positive lens L62 has an aspherical lens surface on the object side.

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

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

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

The tenth lens group G10 is composed of a negative lens L101 having a biconcave shape. The image plane I is arranged on the image side of the tenth lens group G10. That is, the tenth lens group G10 corresponds to the final lens group.

In this embodiment, the 7th lens group G7 is moved to the image plane I side, and the 8th lens group G8 is moved to the object side, thereby moving from a long-distance object to a short-distance object (from an infinite distance object to a finite-distance object). Is focused. That is, the 7th lens group G7 corresponds to the 1st in-focus lens group, and the 8th lens group G8 corresponds to the 2nd in-focus lens group.

Table 3 below lists the specifications of the variable magnification optical system according to the third embodiment.

(Table 3)
[Overall specifications]
Magnification ratio 2.74
θgFP = 0.6319
WMT
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 RD 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]
Side 26 κ = 0.00, A4 = -2.06E-06, A6 = 3.72E-10
A8 = -2.74E-12, A10 = 1.30E-14, A12 = -1.97E-17
Side 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]
Focal length of group origin
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
Point at infinity Point at infinity Point at infinity Short distance Short distance Short 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 expression correspondence 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

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

(Fourth Example)
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 the lens when the variable magnification optical system according to the fourth embodiment changes from the wide-angle end state to the telephoto end state. The variable magnification optical system ZL (4) according to the fourth embodiment has a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a positive lens group G2 arranged in order from the object side. 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, and 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 scaling 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 are separately shown in FIG. 7. It moves in the direction indicated by the arrow, and the distance between adjacent lens groups changes. At the time of scaling, 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 including 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 succeeding lens group GR.

The first lens group G1 is a junction lens of a negative meniscus lens L11 having 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 having a convex surface facing the object side. It is composed of and.

The second lens group G2 includes a negative meniscus lens L21 having a convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L23 having a convex surface facing the object side, which are arranged in order from the object side. It is composed of a concave negative lens L24.

The third lens group G3 is composed of a positive meniscus lens L31 having a convex surface facing the object side.

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

The fifth lens group G5 includes a junction 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 a convex surface facing the object side, and a biconvex lens. It is composed of a junction lens of a positive lens L54 having a shape and a negative meniscus lens L55 having a concave surface facing the object side, and a positive meniscus lens L56 having a convex surface facing the object side. The aperture diaphragm S is arranged 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 at the time of scaling. The positive lens L54 has an aspherical lens surface on the object side.

The sixth lens group G6 is composed of a positive meniscus lens L61 having a concave surface facing the object side and a negative meniscus lens L62 having a convex surface facing the object side, which are arranged in order from the object side.

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

The eighth lens group G8 is composed of a negative meniscus lens L81 having a convex surface facing the object side and a negative meniscus lens L82 having a concave surface facing the object side, which are 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 arranged on the image side of the eighth lens group G8. That is, the eighth lens group G8 corresponds to the final lens group.

In this embodiment, the sixth lens group G6 is moved to the image plane I side, and the seventh lens group G7 is moved to the object side, thereby moving from a long-distance object to a short-distance object (from an infinite distance object to a finite-distance object). Is focused. That is, the sixth lens group G6 corresponds to the first in-focus lens group, and the seventh lens group G7 corresponds to the second in-focus lens group.

Table 4 below lists the values of the specifications of the variable magnification optical system according to the fourth embodiment.

(Table 4)
[Overall specifications]
Magnification ratio 2.74
θgFP = 0.6319
WMT
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 RD 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]
Surface 26 κ = 0.00, A4 = -1.87E-06, A6 = -4.52E-10
A8 = 3.30E-12, A10 = -9.39E-15, A12 = 1.05E-17
Side 37 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]
Focal length of group origin
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
Point at infinity Point at infinity Point at infinity Short distance Short distance Short 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 expression correspondence value]
Conditional expression (1) f3 / (-fE) = 1.37
Conditional expression (2) f1 / (-fE) = 1.85
Conditional expression (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

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

(Fifth Example)
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 the lens when the variable magnification optical system according to the fifth embodiment changes from the wide-angle end state to the telephoto end state. The variable magnification optical system ZL (5) according to the fifth embodiment has a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a positive lens group G2 arranged in order from the object side. 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, and a sixth lens group G6 having a positive refractive power. It is composed of 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 scaling 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 are separately shown in FIG. It moves in the direction indicated by the arrow, and the distance between adjacent lens groups changes. At the time of scaling, 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 consisting of the 4th lens group G4, the 5th lens group G5, the 6th lens group G6, the 7th lens group G7, the 8th lens group G8, and the 9th lens group G9 is the subsequent lens group. Corresponds to GR.

The first lens group G1 is a junction lens of a negative meniscus lens L11 having 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 having a convex surface facing the object side. It is composed of and.

The second lens group G2 has a negative meniscus lens L21 having a convex surface facing the object side, a biconvex positive lens L22, a biconcave negative lens L23, and a concave surface on the object side, which are arranged in order from the object side. It is composed of a negative meniscus lens L24 that is directed.

The third lens group G3 is composed of a positive meniscus lens L31 having a convex surface facing the object side.

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

The fifth lens group G5 is composed of a junction lens of a negative lens L51 having a biconcave shape and a positive meniscus lens L52 having a convex surface facing the object side. The aperture stop S is arranged on the most object side of the fifth lens group G5, and moves together with the fifth lens group G5 at the time of scaling.

The sixth lens group G6 is composed of a negative meniscus lens L61 having a convex surface facing the object side, a biconvex positive lens L62, and a positive meniscus lens L63 having a convex surface facing the object side, which are arranged in order from the object side. Will be done. The positive lens L62 has an aspherical lens surface on the image side.

The seventh lens group G7 is composed of a positive meniscus lens L71 having a concave surface facing the object side and a negative lens L72 having both concave shapes arranged in order from the object side.

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

The ninth lens group G9 is composed of a negative lens L91 having a biconcave shape. The 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.

In this embodiment, the 7th lens group G7 is moved to the image plane I side, and the 8th lens group G8 is moved to the object side, thereby moving from a long-distance object to a short-distance object (from an infinite distance object to a finite-distance object). Is focused. That is, the 7th lens group G7 corresponds to the 1st in-focus lens group, and the 8th lens group G8 corresponds to the 2nd in-focus lens group.

Table 5 below lists the values of the specifications of the variable magnification optical system according to the fifth embodiment.

(Table 5)
[Overall specifications]
Magnification ratio 2.74
θgFP = 0.625146
WMT
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 RD 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]
Surface 27 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]
Focal length of group origin
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
Point at infinity Point at infinity Point at infinity Short distance Short distance Short 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
[Conditional expression correspondence value]
Conditional expression (1) f3 / (-fE) = 2.62
Conditional expression (2) f1 / (-fE) = 2.71
Conditional expression (3) f2 / fE = 0.79
Conditional expression (4) f1 / (-f2) = 3.45
Conditional expression (5) f1 / f3 = 1.03
Conditional expression (6) f1 / f4 = 3.12
Conditional expression (7) (-fF1) /fF2=1.54
Conditional expression (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

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

(6th Example)
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 has a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a positive lens group G2 arranged in order from the object side. 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, and a sixth lens group G6 having a positive refractive power. It is composed of 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 scaling 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 are separately shown in FIG. It moves in the direction indicated by the arrow, and the distance between adjacent lens groups changes. At the time of scaling, 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 consisting of the 4th lens group G4, the 5th lens group G5, the 6th lens group G6, the 7th lens group G7, the 8th lens group G8, and the 9th lens group G9 is the subsequent lens group. Corresponds to GR.

The first lens group G1 is a junction lens of a negative meniscus lens L11 having 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 having a convex surface facing the object side. It is composed of and.

The second lens group G2 includes a negative meniscus lens L21 having a convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L23 having a convex surface facing the object side, which are arranged in order from the object side. It is composed of a concave negative lens L24.

The third lens group G3 is composed of a positive meniscus lens L31 having a convex surface facing the object side.

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

The fifth lens group G5 is composed of a junction lens of a biconcave negative lens L51 and a biconvex positive lens L52. The aperture stop S is arranged on the most object side of the fifth lens group G5, and moves together with the fifth lens group G5 at the time of scaling.

The sixth lens group G6 is a junction lens of a negative meniscus lens L61 having a convex surface facing the object side, a biconvex positive lens L62, and a negative meniscus lens L63 having 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 positive lens L62 has an aspherical lens surface on the object side.

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.

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

The ninth lens group G9 is composed of a biconcave negative lens L91 arranged in order from the object side and a negative meniscus lens L92 with a concave surface facing the object side. The negative lens L91 has an aspherical lens surface on the object side. The 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.

In this embodiment, the 7th lens group G7 is moved to the image plane I side, and the 8th lens group G8 is moved to the object side, thereby moving from a long-distance object to a short-distance object (from an infinite distance object to a finite-distance object). Is focused. That is, the 7th lens group G7 corresponds to the 1st in-focus lens group, and the 8th lens group G8 corresponds to the 2nd in-focus lens group.

Table 6 below lists the values of the specifications of the variable magnification optical system according to the sixth embodiment.

(Table 6)
[Overall specifications]
Magnification ratio 2.74
θgFP = 0.6319
WMT
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 RD 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]
16th surface 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
Side 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]
Focal length of group origin
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
Point at infinity Point at infinity Point at infinity Short distance Short distance Short 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 expression correspondence 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

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

(7th Example)
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 lens when the variable magnification optical system according to the seventh embodiment changes from the wide-angle end state to the telephoto end state. The variable magnification optical system ZL (7) according to the seventh embodiment has a first lens group G1 having a positive refractive power, a second lens group G2 having a negative power, and a positive lens group G2 arranged in order from the object side. A third lens group G3 having a negative power, a fourth lens group G4 having a negative power, a fifth lens group G5 having a positive power, and a sixth lens group G6 having a negative power. Consists of. When scaling 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 are separately oriented in the directions indicated by the arrows in FIG. It moves and the distance between adjacent lens groups changes. At the time of scaling, the first lens group G1 and the sixth lens group G6 are fixed with respect to the image plane I. The lens group including the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 corresponds to the succeeding lens group GR.

The first lens group G1 is a junction lens of a negative meniscus lens L11 having 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 having a convex surface facing the object side. It is composed of and.

The second lens group G2 includes a negative meniscus lens L21 having a convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L having a convex surface facing the object side, which are arranged in order from the object side.
It is composed of 23 and a negative meniscus lens L24 with a concave surface facing the object side.

The third lens group G3 includes a positive meniscus lens L31 having a convex surface facing the object side, a positive meniscus lens L32 having a convex surface facing the object side, and a biconvex positive lens L33 arranged in order from the object side. A junction lens of a concave negative lens L34 and 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 biconvex positive lens L37 and a concave surface on the object side. It is composed of a junction lens with a negative meniscus lens L38 directed toward the object and a positive meniscus lens L39 with a convex surface facing the object side. An aperture diaphragm S is arranged 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 at the time of scaling. The positive lens L37 has an aspherical lens surface on the object side.

The fourth lens group G4 is composed of a positive meniscus lens L41 having a concave surface facing the object side and a negative lens L42 having both concave shapes arranged in order from the object side.

The fifth lens group G5 is composed of a biconvex positive lens L51.

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. The image plane I is arranged on the image side of the sixth lens group G6. That is, the sixth lens group G6 corresponds to the final lens group.

In this embodiment, the fourth lens group G4 is moved to the image plane I side, and the fifth lens group G5 is moved to the object side, thereby moving from a long-distance object to a short-distance object (from an infinite distance object to a finite-distance object). Is focused. That is, the fourth lens group G4 corresponds to the first in-focus lens group, and the fifth lens group G5 corresponds to the second in-focus lens group.

Table 7 below lists the values of the specifications of the variable magnification optical system according to the seventh embodiment.

(Table 7)
[Overall specifications]
Magnification 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 RD 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]
Side 26 κ = 0.00, A4 = -1.61284E-06, A6 = 4.35900E-10
A8 = -1.44229E-12, A10 = 4.93431E-15, A12 = -5.72670E-18
Side 37 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]
Focal length of group origin
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
Point at infinity Point at infinity Point at 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
[Conditional expression correspondence value]
Conditional expression (1) f3 / (-fE) = 0.47
Conditional expression (2) f1 / (-fE) = 1.15
Conditional expression (3) f2 / fE = 0.38
Conditional expression (4) f1 / (-f2) = 3.03
Conditional expression (5) f1 / f3 = 2.43
Conditional expression (6) f1 / f4 = -1.45
Conditional expression (7) (-fF1) /fF2=1.32
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 = 34.09 °
Conditional expression (12) 2ωt = 12.31 °
Conditional expression (13) BFw / fw = 0.44

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

According to each embodiment, it is possible to realize a variable magnification optical system in which various aberrations such as spherical aberration are satisfactorily corrected.

Here, each of the above examples shows a specific example of the present invention, and the present invention is not limited thereto.

The following contents can be appropriately adopted as long as the optical performance of the variable magnification optical system according to the present embodiment is not impaired.

As numerical examples of the variable magnification optical system, those having a 6-group, 7-group, 8-group, 9-group, and 10-group configuration are shown, but the present application is not limited to this, and other group configurations (for example, 5 groups and 5 groups) are shown. It is also possible to configure a variable magnification optical system (11 groups, etc.). Specifically, a lens or a lens group may be added to the most object side or the most image plane side of the variable magnification optical system. The lens group refers to a portion having at least one lens separated by an air interval that changes at the time of scaling.

The lens surface may be formed on a spherical surface or a flat surface, or may be formed on an aspherical surface. When the lens surface is spherical or flat, lens processing and assembly adjustment are facilitated, and deterioration of optical performance due to processing and assembly adjustment errors can be prevented, which is preferable. Further, even if the image plane is displaced, the deterioration of the depiction performance is small, which is preferable.

When the lens surface is an aspherical surface, the aspherical surface is an aspherical surface formed by grinding, a glass mold aspherical surface formed by forming glass into an aspherical surface shape, or a composite aspherical surface formed by forming resin on the glass surface into an aspherical surface shape. It doesn't matter which one. Further, the lens surface may be a diffraction surface, and the lens may be a refractive index distribution type lens (GRIN lens) or a plastic lens.

An antireflection film having a high transmittance in a wide wavelength range may be provided on each lens surface in order to reduce flare and ghosting and achieve high-contrast optical performance. As a result, flare and ghost can be reduced, and high-contrast and high optical performance can be achieved.

G1 1st lens group G2 2nd lens group G3 3rd lens group GR Subsequent lens group I Image plane S Aperture aperture

Claims (14)

It has 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 succeeding lens group arranged in order from the object side. ,
At the time of scaling, the distance between adjacent lens groups changes, and the first lens group is fixed to the image plane.
The third lens group moves when the magnification is changed from the wide-angle end state to the telephoto end state.
The subsequent lens group includes a fourth lens group, a fifth lens group arranged side by side on the image side of the fourth lens group, and a final lens group arranged on the image side most.
A variable magnification optical system that satisfies the following conditional expression.
-10.00 <f3 / (-fE) <3.50
1.20 <f1 / f4 <2.30
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 f4: the focal length of the fourth lens group It has 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 succeeding lens group arranged in order from the object side. ,
At the time of scaling, the distance between adjacent lens groups changes, and the first lens group is fixed to the image plane.
The third lens group moves when the magnification is changed from the wide-angle end state to the telephoto end state.
The subsequent lens group includes a fourth lens group, a fifth lens group arranged side by side on the image side of the fourth lens group, and a final lens group arranged on the image side most.
A variable magnification optical system that satisfies the following conditional expression.
-0.50 <f3 / (-fE) <3.50
-2.00 <f1 / f4 <2.30
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 f4: the focal length of the fourth lens group The variable magnification optical system according to claim 1 or 2, which satisfies the following conditional expression.
-10.00 <f1 / (-fE) <3.50 The variable magnification optical system according to any one of claims 1 to 3, which satisfies the following conditional expression.
-10.00 <f2 / fE <1.50
However, f2: the focal length of the second lens group. The variable magnification optical system according to any one of claims 1 to 4, which satisfies the following conditional expression.
1.50 <f1 / (-f2) <5.00
However, f2: the focal length of the second lens group. The variable magnification optical system according to any one of claims 1 to 5, which satisfies the following conditional expression.
0.80 <f1 / f3 <2.50 The variable magnification optical system according to any one of claims 1 to 6, wherein the final lens group is fixed to the image plane at the time of scaling. The invention according to any one of claims 1 to 7, wherein at least one lens group among the lens groups arranged on the image side of the third lens group is fixed to the image plane at the time of scaling. Variable magnification optical system. The following lens groups are 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, which are arranged in order from the object side. It has a refraction lens group and
The variable magnification optical system according to any one of claims 1 to 8, which satisfies the following conditional expression.
0.80 <(-fF1) /fF2 <5.00
However, fF1: the focal length of the first focusing lens group fF2: the focal length of the second focusing lens group. The variable magnification optical system according to any one of claims 1 to 9, wherein the second lens group has a positive lens satisfying the following conditional expression.
18.0 <νdP <35.0
1.83 <ndP + (0.01425 × νdP) <2.12
0.702 <θgFP + (0.00316 × νdP)
However, νdP: Abbe number ndP based on the d-line of the positive lens: Refractive index θgFP with respect to the d-line of the positive lens: Partial dispersion ratio of the positive lens, and the refractive index of the positive lens with respect to the g-line is ngP. When the refractive index of the positive lens with respect to the F line is nFP and the refractive index of the positive lens with respect to the C line is nCP, θgFP = (ngP-nFP) / (nFP-nCP) defined by the following equation. The variable magnification optical system according to any one of claims 1 to 10, which satisfies the following conditional expression.
25.00 ° <2ωw <50.00 °
However, 2ωw: the total angle of view of the variable magnification optical system in the wide-angle end state. The variable magnification optical system according to any one of claims 1 to 11, which satisfies the following conditional expression.
5.00 ° <2ωt <20.00 °
However, 2ωt: the total angle of view of the variable magnification optical system in the telephoto end state. The variable magnification optical system according to any one of claims 1 to 12, which satisfies the following conditional expression.
0.20 <BFw / fw <0.85
However, BFw: the back focus of the variable magnification optical system in the wide-angle end state fw: the focal length of the variable magnification optical system in the wide-angle end state. An optical device including the variable magnification optical system according to any one of claims 1 to 13.

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