JPWO2020136744A1 - Manufacturing method of variable magnification optical system, optical equipment and variable magnification optical system - Google Patents

Abstract

The variable magnification optical system (ZL) consists of a first lens group (G1) having a positive refractive power, a second lens group (G2) having a negative refractive power, and a positive refractive power 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, and a succeeding lens group (GR). Has changed, and the succeeding lens group (GR) has a focusing lens group that moves at the time of focusing, and satisfies the following conditional expression. 0.80 <f1 / f4 <5.101.20 <f4 / fw <6.80 However, f1: focal length of the first lens group (G1) f4: focal length of the fourth lens group (G4) fw: wide angle Focal length of variable magnification optical system (ZL) in the edge state

Description

The present invention relates to a variable magnification optical system, an optical device using the variable magnification optical system, and a method for manufacturing the variable magnification optical system.

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 a variable magnification optical system, it is required to suppress fluctuations in aberration during scaling or focusing.

Japanese Unexamined Patent Publication No. 2013-160944

The variable magnification optical system according to the first aspect includes 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, a fourth lens group having a positive refractive power, and a succeeding lens group. At the time of scaling, the distance between adjacent lens groups changes, and the succeeding lens group is in focus. It has a focusing lens group that moves at the time of, and satisfies the following conditional expression.
0.80 <f1 / f4 <5.10
1.20 <f4 / fw <6.80
However, f1: the focal length of the first lens group f4: the focal length of the fourth lens group ww: the focal length of the variable magnification optical system in the wide-angle end state.

The optical device according to the second aspect is configured to include the above-mentioned variable magnification optical system.

The method for manufacturing the variable magnification optical system according to the third aspect includes a first lens group having a positive refractive force, a second lens group having a negative refractive force, and a positive refractive force arranged in order from the object side. This is a method for manufacturing a variable magnification optical system having a third lens group having a magnification, a fourth lens group having a positive refractive power, and a subsequent lens group, and when the magnification is changed, adjacent lens groups are used. The subsequent lens group has a focusing lens group that moves at the time of focusing, and each lens is arranged in a lens barrel so as to satisfy the following conditional expression.
0.80 <f1 / f4 <5.10
1.20 <f4 / fw <6.80
However, f1: the focal length of the first lens group f4: the focal length of the fourth lens group ww: the focal length of the variable magnification optical system in the wide-angle end state.

It is a figure which shows the lens structure of the variable magnification optical system which concerns on 1st Example. 2 (A), 2 (B), and 2 (C) show 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 diagram of various aberrations of. 3 (A), 3 (B), and 3 (C) show 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 diagram of various aberrations of. It is a figure which shows the lens structure of the variable magnification optical system which concerns on 2nd Example. 5 (A), 5 (B), and 5 (C) show 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 diagram of various aberrations of. 6 (A), 6 (B), and 6 (C) show 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 diagram of various aberrations of. It is a figure which shows the lens structure of the variable magnification optical system which concerns on 3rd Example. 8 (A), 8 (B), and 8 (C) show 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 diagram of various aberrations of. 9 (A), 9 (B), and 9 (C) show 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, at the time of short-distance focusing. It is a diagram of various aberrations of. It is a figure which shows the lens structure of the variable magnification optical system which concerns on 4th Example. 11 (A), 11 (B), and 11 (C) show 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 diagram of various aberrations of. 12 (A), 12 (B), and 12 (C) show 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, at the time of short-distance focusing. It is a diagram of various aberrations of. It is a figure which shows the lens structure of the variable magnification optical system which concerns on 5th Example. 14 (A), 14 (B), and 14 (C) show 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 at infinity focusing, respectively. It is a diagram of various aberrations of. 15 (A), 15 (B), and 15 (C) show 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, at the time of short-distance focusing. It is a diagram of various aberrations of. It is a figure which shows the lens structure of the variable magnification optical system which concerns on 6th Example. 17 (A), 17 (B), and 17 (C) are at infinity focusing 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 diagram of various aberrations of. 18 (A), 18 (B), and 18 (C) are short-distance focusing 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 diagram of various aberrations of. It is a figure which shows the lens structure of the variable magnification optical system which concerns on 7th Example. 20 (A), 20 (B), and 20 (C) are at infinity focusing 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 diagram of various aberrations of. 21 (A), 21 (B), and 21 (C) show 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, at the time of short-distance focusing. It is a diagram of various aberrations of. 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 the present embodiment will be described with reference to the drawings. First, a camera (optical device) provided with a variable magnification optical system according to the present embodiment will be described with reference to FIG. As shown in FIG. 22, 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 sensor 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 (photographing lens) according to the present embodiment will be described. As an example of the variable magnification optical system (zoom lens) ZL according to the present embodiment, the variable magnification optical system ZL (1) is the first one having a positive refractive power, arranged in order from the object side, as shown in FIG. The lens group G1, the second lens group G2 having a negative refractive power, the third lens group G3 having a positive refractive power, the fourth lens group G4 having a positive refractive power, and the succeeding lens group GR. It is configured so that the distance between adjacent lens groups changes when the magnification is changed. The subsequent lens group GR has a focusing lens group that moves during focusing.

The variable magnification optical system ZL according to the present embodiment has at least five lens groups, and the distance between the lens groups changes at the time of magnification change. Thereby, according to the present embodiment, it is possible to suppress the fluctuation of the aberration at the time of scaling from the wide-angle end state to the telephoto end state. In addition, by arranging the focusing lens group in the succeeding lens group GR, the focusing lens group can be made smaller and lighter, and high-speed and quiet autofocus can be realized without increasing the size of the lens barrel. Will be possible.

The variable magnification optical system ZL according to the present embodiment may be the variable magnification optical system ZL (2) shown in FIG. 4, the variable magnification optical system ZL (3) shown in FIG. 7, or the variable magnification optical system shown in FIG. 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. 13, the variable magnification optical system ZL (6) shown in FIG. 16, or the variable magnification optical system ZL (6) shown in FIG. The optical system ZL (7) may be used.

Under the above configuration, the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expressions (1) and (2).

0.80 <f1 / f4 <5.10 ... (1)
1.20 <f4 / fw <6.80 ... (2)
However, f1: focal length of the first lens group G1 f4: focal length of the fourth lens group G4 fw: focal length of the variable magnification optical system ZL in the wide-angle end state.

The conditional expression (1) 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 (1), it is possible to suppress fluctuations in various aberrations such as spherical aberration when scaling from the wide-angle end state to the telephoto end state.

If the corresponding value of the conditional expression (1) exceeds the upper limit value, the refractive power of the fourth lens group G4 becomes too strong, and it becomes difficult to suppress fluctuations in various aberrations such as spherical aberration during scaling. Become. By setting the upper limit value of the conditional expression (1) to 4.50, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (1) is set to 4.00, 3.50, 3.00, 2.50, 2.00, 1.80, 1 It may be set to .65, 1.60, and further 1.55.

If the corresponding value of the conditional expression (1) is less than the lower limit value, the refractive power of the first lens group G1 becomes too strong, and it becomes difficult to suppress fluctuations of various aberrations such as spherical aberration at the time of scaling. Become. By setting the lower limit value of the conditional expression (1) to 0.82, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (1) is set to 0.84, 0.85, 0.88, 0.90, 0.92, 0.95, 0. It may be set to .96, 0.97, 0.98, and further 1.00.

Conditional expression (2) defines the ratio between the focal length of the fourth lens group G4 and the focal length of the variable magnification optical system ZL in the wide-angle end state. By satisfying the conditional expression (2), it is possible to suppress fluctuations in various aberrations such as spherical aberration when scaling from the wide-angle end state to the telephoto end state.

If the corresponding value of the conditional expression (2) exceeds the upper limit value, the refractive power of the fourth lens group G4 becomes too weak, and it becomes difficult to suppress fluctuations of various aberrations such as spherical aberration at the time of magnification change. Become. By setting the upper limit value of the conditional expression (2) to 6.70, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (2) is set to 6.60, 6.50, 6.30, 6.00, 5.80, 5.50, 5 It may be set to .30, 5.00, 4.90, and further 4.80.

If the corresponding value of the conditional expression (2) is less than the lower limit value, the refractive power of the fourth lens group G4 becomes too strong, and it becomes difficult to suppress fluctuations of various aberrations such as spherical aberration at the time of scaling. Become. By setting the lower limit value of the conditional expression (2) to 1.50, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (2) is set to 2.00, 2.50, 2.80, 2.90, 3.00, 3.10, 3 It may be set to .20, 3.30, 3.40, and further 3.50.

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

0.20 <f3 / f4 <2.50 ... (3)
However, f3: focal length of the third lens group G3

The conditional expression (3) defines the ratio between the focal length of the third lens group G3 and the focal length of the fourth lens group G4. By satisfying the conditional expression (3), it is possible to suppress fluctuations in various aberrations such as spherical aberration when scaling from the wide-angle end state to the telephoto end state.

If the corresponding value of the conditional expression (3) exceeds the upper limit value, the refractive power of the fourth lens group G4 becomes too strong, and it becomes difficult to suppress fluctuations in various aberrations such as spherical aberration during scaling. Become. By setting the upper limit value of the conditional expression (3) to 2.40, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (3) is set to 2.30, 2.20, 2.10, 2.00, 1.90, 1.80, 1 It may be set to .50, 1.30, 1.00, and further 0.90.

If the corresponding value of the conditional expression (3) is less than the lower limit value, the refractive power of the third lens group G3 becomes too strong, and it becomes difficult to suppress fluctuations of various aberrations such as spherical aberration at the time of scaling. Become. By setting the lower limit value of the conditional expression (3) to 0.22, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (3) is set to 0.25, 0.28, 0.30, 0.31, 0.32, 0.33, and further. It may be set to 0.34.

In the variable magnification optical system ZL according to the present embodiment, the first lens group G1 has an eleventh lens having a negative refractive power and a twelfth lens having a positive refractive power arranged in order from the object side. , It is desirable that the following conditional expression (4) is satisfied.

0.010 <dP1 / f1 <0.075 ... (4)
However, dP1: the sum of the center thickness of the 11th lens and the center thickness of the 12th lens.

The conditional expression (4) defines the ratio of the sum of the center thickness of the eleventh lens and the center thickness of the twelfth lens to the focal length of the first lens group G1. By satisfying the conditional expression (4), it is possible to suppress fluctuations in various aberrations such as spherical aberration when scaling from the wide-angle end state to the telephoto end state.

If the corresponding value of the conditional expression (4) exceeds the upper limit value, the refractive power of the first lens group G1 becomes too strong, and it becomes difficult to suppress fluctuations in various aberrations such as spherical aberration during scaling. Become. By setting the upper limit value of the conditional expression (4) to 0.074, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (4) is set to 0.072, 0.070, 0.069, 0.068, 0.067, and further 0.066. It may be set.

If the corresponding value of the conditional expression (4) is less than the lower limit value, the refractive power of the first lens group G1 becomes too weak, and the lens barrel becomes large. In addition, it becomes difficult to suppress fluctuations in various aberrations such as spherical aberration during scaling. By setting the lower limit value of the conditional expression (4) to 0.015, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of the present embodiment, the lower limit of the conditional expression (4) is set to 0.020, 0.025, 0.030, 0.033, 0.035, 0.038, and further. It may be set to 0.040.

In the variable magnification optical system ZL according to the present embodiment, it is desirable that the focusing lens group consists of three or less single lenses. As a result, the focusing lens group can be made smaller and lighter.

In the variable magnification optical system ZL according to the present embodiment, it is desirable that at least one of the focusing lens groups has a single lens having a negative refractive power. As a result, fluctuations in various aberrations such as spherical aberration during focusing from an infinity object to a short-distance object can be suppressed.

In the variable magnification optical system ZL according to the present embodiment, it is desirable that the focusing lens group is arranged on the image side of the aperture diaphragm S. As a result, the focusing lens group can be made smaller and lighter.

In the variable magnification optical system ZL according to the present embodiment, it is desirable that at least four lens groups are arranged on the image side of the aperture diaphragm S. This makes it possible to suppress fluctuations in various aberrations such as spherical aberration when scaling from the wide-angle end state to the telephoto end state.

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

0.20 << | fF | / ft <4.00 ... (5)
However, fF: the focal length of the focusing lens group having the strongest refractive power among the focusing lens groups ft: the focal length of the variable magnification optical system ZL in the telephoto end state.

Conditional expression (5) defines the ratio between the focal length of the focusing lens group having the strongest refractive power among the focusing lens groups and the focal length of the variable magnification optical system ZL in the telephoto end state. By satisfying the conditional equation (5), it is possible to suppress fluctuations in various aberrations such as spherical aberration when focusing from an infinite object to a short-distance object without increasing the size of the lens barrel.

If the corresponding value of the conditional expression (5) exceeds the upper limit value, the refractive power of the focusing lens group becomes too weak, so that the amount of movement of the focusing lens group during focusing becomes large and the lens barrel becomes large. .. By setting the upper limit value of the conditional expression (5) to 3.80, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (5) is set to 3.60, 3.40, 3.20, 3.00, 2.80, 2.60, 2 It may be set to .40, 2.20, and further 2.00.

If the corresponding value of the conditional expression (5) is less than the lower limit value, the refractive power of the focusing lens group becomes too strong, and it becomes difficult to suppress fluctuations in various aberrations such as spherical aberration during focusing. .. By setting the lower limit value of the conditional expression (5) to 0.23, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of the present embodiment, the lower limit of the conditional expression (5) may be set to 0.25, 0.28, 0.30, 0.33, and further 0.35. good.

In the variable magnification optical system ZL according to the present embodiment, it is desirable that the fourth lens group G4 has a junction lens of a negative lens and a positive lens. This makes it possible to suppress fluctuations in various aberrations such as spherical aberration when scaling from the wide-angle end state to the telephoto end state.

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

1.00 <nN / nP <1.35 ... (6)
However, nN: the refractive index of the negative lens in the junction lens nP: the refractive index of the positive lens in the junction lens.

Conditional expression (6) defines the ratio of the refractive index of the negative lens to the refractive index of the positive lens in the junction lens in the fourth lens group G4. By satisfying the conditional expression (6), it is possible to suppress fluctuations in various aberrations such as spherical aberration when scaling from the wide-angle end state to the telephoto end state.

When the corresponding value of the conditional expression (6) exceeds the upper limit value, the refractive power of the negative lens in the junction lens becomes too strong, so that the correction of spherical aberration in the telephoto end state becomes excessive, and the wide-angle end state changes to the telephoto end state. It becomes difficult to suppress fluctuations in various aberrations such as spherical aberration when the magnification is changed. By setting the upper limit value of the conditional expression (6) to 1.33, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (6) is set to 1.30, 1.29, 1.28, 1.27, 1.26, and further 1.25. You may set it.

When the corresponding value of the conditional expression (6) is less than the lower limit value, the refractive power of the negative lens in the junction lens becomes too weak, so that the correction of spherical aberration in the telephoto end state is insufficient, and the wide-angle end state is changed to the telephoto end state. It becomes difficult to suppress fluctuations in various aberrations such as spherical aberration during scaling. By setting the lower limit value of the conditional expression (6) to 1.02, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (6) is set to 1.05, 1.08, 1.10, 1.11, 1.12, 1.13, 1 It may be set to .14 and 1.15.

In the variable magnification optical system ZL according to the present embodiment, the fourth lens group G4 has a junction lens of a negative lens and a positive lens, and it is desirable that the following conditional expression (7) is satisfied.

0.20 <νN / νP <0.85 ・ ・ ・ (7)
However, νN: Abbe number of the negative lens in the junction lens νP: Abbe number of the positive lens in the junction lens

Conditional expression (7) defines the ratio of the Abbe number of the negative lens to the Abbe number of the positive lens in the junction lens in the fourth lens group G4. By satisfying the conditional expression (7), chromatic aberration can be satisfactorily corrected.

When the corresponding value of the conditional expression (7) exceeds the upper limit value, the Abbe number of the positive lens in the junction lens becomes small, so that chromatic aberration is excessively generated and it becomes difficult to correct the chromatic aberration. By setting the upper limit value of the conditional expression (7) to 0.83, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of the present embodiment, the upper limit of the conditional expression (7) is set to 0.80, 0.78, 0.75, 0.73, 0.70, 0.68, 0. It may be set to .65, 0.63, 0.60, 0.58, 0.55, 0.53, and further 0.50.

When the corresponding value of the conditional expression (7) is less than the lower limit value, the Abbe number of the negative lens in the bonded lens becomes small, so that the correction of chromatic aberration becomes excessive. By setting the lower limit value of the conditional expression (7) to 0.22, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (7) is set to 0.24, 0.25, 0.26, 0.27, 0.28, and further 0.29. It may be set.

It is desirable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (8).

f1 / | fRw | <5.00 ... (8)
However, fRw: the focal length of the subsequent lens group GR in the wide-angle end state.

Conditional expression (8) defines the ratio of the focal length of the first lens group G1 to the focal length of the subsequent lens group GR in the wide-angle end state. By satisfying the conditional expression (8), it is possible to suppress fluctuations in various aberrations such as spherical aberration when scaling from the wide-angle end state to the telephoto end state.

If the corresponding value of the conditional expression (8) exceeds the upper limit value, the refractive power of the subsequent lens group GR becomes too strong, and it becomes difficult to suppress fluctuations in various aberrations such as spherical aberration during scaling. .. By setting the upper limit value of the conditional expression (8) to 4.80, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (8) is set to 4.60, 4.40, 4.20, 4.00, 3.80, 3.50, 3 It may be set to .00, 2.80, 2.50, 2.30, 2.00, 1.80, and further 1.50.

It is desirable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (9).

2ωw> 75 ° ・ ・ ・ (9)
However, ωw: half angle of view of the variable magnification optical system ZL in the wide-angle end state

The conditional expression (9) defines the half angle of view of the variable magnification optical system ZL in the wide-angle end state. By satisfying the conditional expression (9), it is possible to suppress fluctuations in aberration during scaling from the wide-angle end state to the telephoto end state while having a wide angle of view. By setting the lower limit value of the conditional expression (9) to 76 °, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of the present embodiment, the lower limit of the conditional expression (9) may be set to 77 °, 78 °, 79 °, 80 °, 81 °, and further 82 °.

It is desirable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (10).

0.10 <BFw / fw <1.00 ... (10)
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.

Conditional expression (10) 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 (10), various aberrations such as coma in the wide-angle end state can be satisfactorily corrected.

When the corresponding value of the conditional expression (10) 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 (10) to 0.95, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (10) is set to 0.90, 0.85, 0.80, 0.78, 0.75, 0.73, 0. It may be set to .70, 0.68, and further 0.65.

When the corresponding value of the conditional equation (10) is less than the lower limit value, 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 (10) to 0.15, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (10) is set to 0.20, 0.25, 0.30, 0.35, 0.37, 0.38, 0. It may be set to .40, 0.42, 0.44, and further 0.45.

In the variable magnification optical system ZL according to the present embodiment, when the focusing lens group has a positive refractive power, it is desirable that the following conditional expression (11) is satisfied.

0.00 <(rR2 + rR1) / (rR2-rR1) <8.00 ... (11)
However, rR1: radius of curvature of the lens surface on the object side of the lens arranged on the most image side of the variable magnification optical system ZL rR2: the lens surface on the image side of the lens arranged on the most image side of the variable magnification optical system ZL. curvature radius

The conditional expression (11) defines the shape factor of the lens arranged on the image side of the variable magnification optical system ZL. By satisfying the conditional expression (11), it is possible to suppress fluctuations in various aberrations such as spherical aberration when scaling from the wide-angle end state to the telephoto end state.

If the corresponding value of the conditional expression (11) exceeds the upper limit value, the correction power of the coma aberration of the lens arranged on the image side of the scaling optical system ZL is insufficient, so that the fluctuations of various aberrations at the time of scaling are affected. It becomes difficult to suppress. By setting the upper limit value of the conditional expression (11) to 7.50, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (11) is set to 7.00, 6.80, 6.50, 6.30, 6.00, 5.80, 5 It may be set to .50, 5.30, and further 5.00.

When the corresponding value of the conditional expression (11) is less than the lower limit value, the correction power of the coma aberration of the lens arranged on the image side of the scaling optical system ZL is insufficient, so that the fluctuations of various aberrations at the time of scaling are affected. It becomes difficult to suppress. By setting the lower limit value of the conditional expression (11) to 0.10, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (11) is set to 0.50, 0.80, 1.00, 1.20, 1.50, 1.80, 2 It may be set to .00, 2.20, and further 2.50.

In the variable magnification optical system ZL according to the present embodiment, when the focusing lens group has a negative refractive power, it is desirable that the following conditional expression (12) is satisfied.

-4.00 <(rR2 + rR1) / (rR2-rR1) <4.00 ... (12)
However, rR1: radius of curvature of the lens surface on the object side of the lens arranged on the most image side of the variable magnification optical system ZL rR2: the lens surface on the image side of the lens arranged on the most image side of the variable magnification optical system ZL. curvature radius

The conditional expression (12) defines the shape factor of the lens arranged on the image side of the variable magnification optical system ZL. By satisfying the conditional expression (12), it is possible to suppress fluctuations in various aberrations such as spherical aberration when scaling from the wide-angle end state to the telephoto end state.

If the corresponding value of the conditional expression (12) exceeds the upper limit value, the correction power of the coma aberration of the lens arranged on the image side of the scaling optical system ZL is insufficient, so that the fluctuations of various aberrations at the time of scaling are affected. It becomes difficult to suppress. By setting the upper limit value of the conditional expression (12) to 3.80, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (12) is set to 3.50, 3.30, 3.00, 2.80, 2.50, 2.30, 2 It may be set to 0.00, 1.80, and further 1.50.

When the corresponding value of the conditional expression (12) is less than the lower limit value, the correction power of the coma aberration of the lens arranged on the image side of the variable magnification optical system ZL is insufficient, so that the fluctuations of various aberrations at the time of magnification change are caused. It becomes difficult to suppress. By setting the lower limit value of the conditional expression (12) to -3.80, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (12) is set to -3.50, -3.30, -3.00, -2.80, -2.50, and so on. It may be set to -2.30, -2.00, -1.80, and further -1.50.

Subsequently, the manufacturing method of the variable magnification optical system ZL according to the present embodiment will be outlined with reference to FIG. 23. 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 positive refractive power. The fourth lens group G4 having the above lens group G4 and the succeeding lens group GR are arranged (step ST1). Then, at the time of scaling, the distance between adjacent lens groups is changed (step ST2). Further, a focusing lens group that moves at the time of focusing is arranged in 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 expressions (1) and (2) (step ST4). According to such a manufacturing method, it is possible to realize high-speed and quiet autofocus without increasing the size of the lens barrel, and the fluctuation of aberration at the time of scaling from the wide-angle end state to the telephoto end state, and It is possible to manufacture a variable magnification optical system that suppresses fluctuations in aberration during focusing from an infinity object to a short-range object.

Hereinafter, the variable magnification optical system ZL according to each embodiment will be described with reference to the drawings. 1, FIG. 4, FIG. 7, FIG. 10, FIG. 13, FIG. 16, and FIG. 19 show the configuration and configuration of the variable magnification optical system ZL {ZL (1) to ZL (7)} according to the first to seventh embodiments. It is sectional drawing which shows the refractive power distribution. The first to seventh embodiments are examples corresponding to the present embodiment. In each cross-sectional view, the moving direction along the optical axis of each lens group when scaling from the wide-angle end state (W) to the telephoto end state (T) 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 word "focusing".

In these figures (FIGS. 1, FIG. 4, FIG. 7, FIG. 10, FIG. 13, FIG. 16, FIG. 19), 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 the symbols and numbers from becoming large and complicated, the lens group and the like are represented by independently using combinations of the symbols 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. Among them, 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, f is the focal length of the entire lens system, FNO is the F number, 2ω is the angle of view (unit is ° (degrees), and ω is the half angle of view), and Ymax is the maximum image height. Is shown. 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 [Overall specifications] table, fRw indicates the focal length of the subsequent lens group in the wide-angle end state.

In the [Lens Specifications] table, the surface numbers indicate the order of the optical surfaces from the object side along the direction in which the light beam travels, and R is the radius of curvature of each optical surface (the surface 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 based on the d-line of the material of the member is shown. 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 aspherical, the surface number is marked with * and the radius of curvature R indicates the paraxial radius of curvature.

In the table of [Aspherical surface data], the shape of the aspherical surface shown in [Lens specifications] is shown by the following equation (A). X (y) is the distance (zag amount) along the optical axis direction from the tangent plane at the aspherical apex to the position on the aspherical surface at the height y, and R is the radius of curvature of the reference sphere (near axis curvature radius). , 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・・ ・ (A)

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

The table of [variable spacing data] shows the surface spacing with the plane number in which the surface spacing is "variable" in the table showing [lens specifications]. Here, the surface spacings at the wide-angle end (W), the intermediate focal length (M), and the telephoto end (T) are shown for each of the in-focus and short-distance focusing states.

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 3 and Table 1. FIG. 1 is a diagram showing a lens configuration of a variable magnification optical system according to the first embodiment. 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 an aperture arranged in order from the object side. Aperture S, 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 third lens group having a positive refractive power. It is composed of a 6-lens group G6 and a 7th lens group G7 having a negative refractive power. When scaling from the wide-angle end state (W) to the telephoto end state (T), the first to seventh lens groups G1 to G7 move in the directions indicated by the arrows in FIG. Change. The lens group including the fifth lens group G5, the sixth lens group G6, and the seventh lens group G7 corresponds to the succeeding lens group GR, and has a negative refractive power as a whole. 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 positive lens of a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side, which are arranged in order from the object side, and a convex surface facing the object side. It is composed of a positive meniscus lens L13. The negative meniscus lens L11 corresponds to the eleventh lens. The positive meniscus lens L12 corresponds to the twelfth lens.

The second lens group G2 has a negative meniscus lens L21 having a convex surface facing the object side, a negative lens L22 having a biconcave shape, a positive lens L23 having a biconvex shape, 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 negative meniscus lens L21 has an aspherical lens surface on the object side.

The third lens group G3 is composed of a positive meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32 arranged in order from the object side. The aperture diaphragm S is provided near the object side of the third lens group G3, and moves together with the third lens group G3 at the time of scaling. The positive meniscus lens L31 has an aspherical lens surface on the object side.

The fourth lens group G4 is composed of a junction positive lens of a negative meniscus lens L41 having a convex surface facing the object side and a biconvex positive lens L42.

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

The sixth lens group G6 is composed of a positive meniscus lens L61 with a concave surface facing the object side. The positive meniscus lens L61 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, a negative lens L72 having a concave shape, and a negative meniscus lens L73 having a concave surface facing the object side, which are arranged in order from the object side. Will be done. The negative lens L72 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.

In this embodiment, by moving the fifth lens group G5 and the sixth lens group G6 independently to the object side, focusing from a long-distance object to a short-distance object (from an infinity object to a finite-distance object) is achieved. Will be done. That is, the fifth lens group G5 corresponds to the first focusing lens group, and the sixth lens group G6 corresponds to the second focusing lens group.

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

(Table 1)
[Overall specifications]
Variable ratio 2.74
fRw = -4993.677
WMT
f 24.8 50.0 67.9
FNO 2.92 2.92 2.92
2ω 85.10 45.26 33.84
Ymax 21.60 21.60 21.60
TL 139.35 158.45 169.16
BF 11.93 23.42 28.62
[Lens specifications]
Surface number RD nd νd
Object surface ∞
1 234.3873 2.500 1.84666 23.80
2 109.5180 5.200 1.75500 52.34
3 389.6852 0.200
4 59.0627 5.700 1.77250 49.62
5 135.3649 D5 (variable)
6 * 218.4420 2.000 1.74389 49.53
7 18.6957 9.658
8 -59.6856 1.300 1.77250 49.62
9 59.6856 0.442
10 39.2099 6.400 1.72825 28.38
11 -48.6731 1.933
12 -26.4065 1.300 1.61800 63.34
13 -71.7612 D13 (variable)
14 ∞ 1.712 (Aperture S)
15 * 71.8876 2.500 1.69370 53.32
16 127.6411 0.716
17 38.7492 5.900 1.59319 67.90
18 -105.4274 D18 (variable)
19 67.0276 1.300 1.73800 32.33
20 19.5126 9.700 1.49782 82.57
21 -50.5609 D21 (variable)
22 -23.9237 1.200 1.72047 34.71
23 -56.2081 0.200
24 103.1749 5.900 1.59349 67.00
25 -33.0197 D25 (variable)
26 -70.6288 3.500 1.79189 45.04
27 * -38.2153 D27 (variable)
28 -43.9824 3.000 1.94595 17.98
29 -32.4253 0.200
30 * -100.5837 1.500 1.85207 40.15
31 88.1634 7.847
32 -25.2838 1.400 1.58913 61.22
33 -45.3661 BF
Image plane ∞
[Aspherical data]
Side 6 κ = 1.0000, A4 = 5.27866E-06, A6 = -5.41835E-09
A8 = 1.333113E-11, A10 = -2.04336E-14, A12 = 2.05090E-17
Surface 15 κ = 1.0000, A4 = -4.55747E-06, A6 = -1.40092E-10
A8 = -8.81384E-13, A10 = -8.42653E-15, A12 = 0.00000E + 00
Side 27 κ = 1.0000, A4 = 1.09543E-05, A6 = -2.36281E-08
A8 = 1.42728E-10, A10 = -5.02724E-13, A12 = 7.51800E-16
Side 30 κ = 1.0000, A4 = -2.189113E-06, A6 = -2.29301E-08
A8 = 3.945582E-11, A10 = -9.84200E-14, A12 = 0.00000E + 00
[Lens group data]
Focal length
G1 1 119.124
G2 6 -22.126
G3 14 40.880
G4 19 115.687
G5 22 124.717
G6 26 100.365
G7 28 -47.354
[Variable interval data]
W M T W M T
Infinity Infinity Infinity Infinity Short distance Short distance Short distance
D5 1.780 21.220 30.246 1.780 21.220 30.246
D13 19.285 6.132 2.013 19.285 6.132 2.013
D18 9.167 3.866 1.493 9.167 3.866 1.493
D21 5.179 14.279 19.018 4.137 12.991 17.666
D25 2.679 3.515 2.616 3.249 4.079 3.027
D27 6.128 2.807 1.953 6.600 3.530 2.893
[Conditional expression correspondence value]
Conditional expression (1) f1 / f4 = 1.030
Conditional expression (2) f4 / fw = 4.674
Conditional expression (3) f3 / f4 = 0.353
Conditional expression (4) dP1 / f1 = 0.065
Conditional expression (5) | fF | / ft = 1.837
Conditional expression (6) nN / nP = 1.160
Conditional expression (7) νN / νP = 0.392
Conditional expression (8) f1 / | fRw | = 0.024
Conditional expression (9) 2ωw = 85.10
Conditional expression (10) BFw / fw = 0.482
Conditional expression (11) (rR2 + rR1) / (rR2-rR1) = 3.518

2 (A), 2 (B), and 2 (C) show 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 diagram of various aberrations of. 3 (A), 3 (B), and 3 (C) show 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 diagram of various aberrations of.

In each aberration diagram of FIGS. 2 (A) to 2 (C), 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 value of the image height, and the transverse aberration diagram shows the value of each image height. In each aberration diagram of FIGS. 3 (A) to 3 (C), NA indicates the numerical aperture and Y indicates the image height. The spherical aberration diagram shows the numerical aperture value 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. Further, in each aberration diagram, 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 of the following examples, the same reference numerals as those of the present embodiment will be used, and duplicate description will be omitted.

From each aberration diagram, the variable magnification optical system according to the first embodiment satisfactorily corrects various aberrations from the wide-angle end state to the telephoto end state and has excellent imaging performance, and further, at the time of short-distance focusing. It can be seen that also has excellent imaging performance.

(Second Example)
The second embodiment will be described with reference to FIGS. 4 to 6 and Table 2. FIG. 4 is a diagram showing a lens configuration of the variable magnification optical system according to the second embodiment. 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 an aperture arranged in order from the object side. Aperture S, 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 third lens group having a positive refractive power. It is composed of a 6-lens group G6 and a 7th lens group G7 having a negative refractive power. When scaling from the wide-angle end state (W) to the telephoto end state (T), the first to seventh lens groups G1 to G7 move in the directions indicated by the arrows in FIG. Change. The lens group including the fifth lens group G5, the sixth lens group G6, and the seventh lens group G7 corresponds to the succeeding lens group GR, and has a negative refractive power as a whole.

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

The second lens group G2 has a negative meniscus lens L21 having a convex surface facing the object side, a negative lens L22 having a biconcave shape, a positive lens L23 having a biconvex shape, 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 negative meniscus lens L21 has an aspherical lens surface on the object side.

The third lens group G3 is composed of a biconvex positive lens L31 and a biconvex positive lens L32 arranged in order from the object side. The aperture diaphragm S is provided near the object side of the third lens group G3, and moves together with the third lens group G3 at the time of scaling. The positive lens L31 has an aspherical lens surface on the object side.

The fourth lens group G4 is composed of a junction positive lens of a negative meniscus lens L41 having a convex surface facing the object side and a biconvex positive lens L42.

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

The sixth lens group G6 is composed of a positive meniscus lens L61 with a concave surface facing the object side. The positive meniscus lens L61 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, a negative lens L72 having a concave shape, and a negative meniscus lens L73 having a concave surface facing the object side, which are arranged in order from the object side. Will be done. The negative lens L72 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.

In this embodiment, by moving the fifth lens group G5 and the sixth lens group G6 independently to the object side, focusing from a long-distance object to a short-distance object (from an infinity object to a finite-distance object) is achieved. Will be done. That is, the fifth lens group G5 corresponds to the first focusing lens group, and the sixth lens group G6 corresponds to the second focusing lens group.

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

(Table 2)
[Overall specifications]
Variable ratio 2.74
fRw = -346.533
WMT
f 24.8 50.0 67.9
FNO 2.92 2.92 2.92
2ω 85.08 45.32 33.84
Ymax 21.60 21.60 21.60
TL 139.96 156.15 168.00
BF 11.76 26.07 29.33
[Lens specifications]
Surface number RD nd νd
Object surface ∞
1 282.3733 2.500 1.84666 23.80
2 123.2365 5.647 1.77250 49.62
3 1180.1775 0.200
4 59.2907 4.310 1.81600 46.59
5 98.9987 D5 (variable)
6 * 205.3191 2.000 1.74389 49.53
7 19.2200 9.185
8-74.7032 1.300 1.83481 42.73
9 64.3697 0.324
10 41.9771 5.683 1.78472 25.64
11 -72.0408 4.071
12 -26.6709 1.300 1.60300 65.44
13 -52.5345 D13 (variable)
14 ∞ 1.500 (Aperture S)
15 * 84.6431 3.039 1.58913 61.15
16 -4073.6051 0.200
17 42.4140 5.438 1.59319 67.90
18 -143.7473 D18 (variable)
19 74.9775 1.300 1.73800 32.33
20 20.9860 9.090 1.49782 82.57
21 -48.9247 D21 (variable)
22 -23.9603 1.200 1.73800 32.33
23 -52.8529 0.955
24 113.2572 5.800 1.59349 66.99
25 -32.1120 D25 (variable)
26 -120.6162 3.500 1.74389 49.53
27 * -50.8923 D27 (variable)
28 -61.4253 3.215 1.94595 17.98
29 -34.3446 0.200
30 * -69.3409 1.500 1.85108 40.12
31 72.0715 6.683
32 -23.1150 1.400 1.69680 55.52
33 -36.7553 BF
Image plane ∞
[Aspherical data]
Side 6 κ = 1.0000, A4 = 4.34838E-06, A6 = -2.30274E-09
A8 = 1.34342E-12, A10 = 2.08876E-15, A12 = 0.00000E + 00
Surface 15 κ = 1.0000, A4 = -4.08736E-06, A6 = 2.82731E-09
A8 = -1.71368E-11, A10 = 2.81580E-14, A12 = 0.00000E + 00
Side 27 κ = 1.0000, A4 = 9.73730E-06, A6 = -1.31611E-08
A8 = 7.02329E-11, A10 = -1.28887E-13, A12 = 0.00000E + 00
Side 30 κ = 1.0000, A4 = -3.68898E-06, A6 = -1.92901E-08
A8 = 3.36794E-11, A10 = -8.19805E-14, A12 = 0.00000E + 00
[Lens group data]
Focal length
G1 1 133.226
G2 6 -23.579
G3 14 40.561
G4 19 115.254
G5 22 113.536
G6 26 115.868
G7 28 -42.726
[Variable interval data]
W M T W M T
Infinity Infinity Infinity Infinity Short distance Short distance Short distance
D5 2.000 18.194 30.046 2.000 18.194 30.046
D13 21.479 6.645 2.000 21.479 6.645 2.000
D18 9.801 4.462 1.500 9.801 4.462 1.500
D21 5.195 13.414 18.760 4.220 12.328 17.590
D25 2.295 3.824 2.737 2.742 4.222 2.950
D27 5.890 2.000 2.087 6.417 2.689 3.043
[Conditional expression correspondence value]
Conditional expression (1) f1 / f4 = 1.156
Conditional expression (2) f4 / fw = 4.657
Conditional expression (3) f3 / f4 = 0.352
Conditional expression (4) dP1 / f1 = 0.061
Conditional expression (5) | fF | / ft = 1.706
Conditional expression (6) nN / nP = 1.160
Conditional expression (7) νN / νP = 0.392
Conditional expression (8) f1 / | fRw | = 0.384
Conditional expression (9) 2ωw = 85.08
Conditional expression (10) BFw / fw = 0.475
Conditional expression (11) (rR2 + rR1) / (rR2-rR1) = 4.389

5 (A), 5 (B), and 5 (C) show 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 diagram of various aberrations of. 6 (A), 6 (B), and 6 (C) show 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 diagram of various aberrations of. From each aberration diagram, the variable magnification optical system according to the second embodiment satisfactorily corrects various aberrations from the wide-angle end state to the telephoto end state and has excellent imaging performance, and further, at the time of short-distance focusing. It can be seen that also has excellent imaging performance.

(Third Example)
The third embodiment will be described with reference to FIGS. 7 to 9 and Table 3. FIG. 7 is a diagram showing a lens configuration of a variable magnification optical system according to a third embodiment. The variable magnification optical system ZL (3) according to the third embodiment has a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and an aperture arranged in order from the object side. Aperture S, 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 third lens group having a positive refractive power. It is composed of a 6-lens group G6 and a 7th lens group G7 having a negative refractive power. When scaling from the wide-angle end state (W) to the telephoto end state (T), the first to seventh lens groups G1 to G7 move in the directions indicated by the arrows in FIG. Change. The lens group including the fifth lens group G5, the sixth lens group G6, and the seventh lens group G7 corresponds to the succeeding lens group GR, and has a negative refractive power as a whole.

The first lens group G1 is a junction positive 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 having a convex surface facing the object side. It is composed of L13. The negative meniscus lens L11 corresponds to the eleventh lens. The positive lens L12 corresponds to the twelfth lens.

The second lens group G2 has a negative meniscus lens L21 having a convex surface facing the object side, a negative lens L22 having a biconcave shape, a positive lens L23 having a biconvex shape, 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 negative meniscus lens L21 has an aspherical lens surface on the object side.

The third lens group G3 is composed of a positive meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32 arranged in order from the object side. The aperture diaphragm S is provided near the object side of the third lens group G3, and moves together with the third lens group G3 at the time of scaling. The positive meniscus lens L31 has an aspherical lens surface on the object side.

The fourth lens group G4 is composed of a junction positive lens of a negative meniscus lens L41 having a convex surface facing the object side and a biconvex positive lens L42.

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

The sixth lens group G6 is composed of a positive meniscus lens L61 with a concave surface facing the object side. The positive meniscus lens L61 has an aspherical lens surface on the image side.

The seventh lens group G7 includes a negative meniscus lens L71 having a convex surface facing the object side, a positive meniscus lens L72 having a concave surface facing the object side, and a negative meniscus lens L72 having a concave surface facing the object side, arranged in order from the object side. It is composed of L73. The negative meniscus lens L73 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.

In this embodiment, by moving the fifth lens group G5 and the sixth lens group G6 independently to the object side, focusing from a long-distance object to a short-distance object (from an infinity object to a finite-distance object) is achieved. Will be done. That is, the fifth lens group G5 corresponds to the first focusing lens group, and the sixth lens group G6 corresponds to the second focusing lens group.

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

(Table 3)
[Overall specifications]
Variable magnification ratio 3.33
fRw = -219.096
WMT
f 24.8 50.0 82.5
FNO 2.92 2.92 2.92
2ω 85.12 45.44 28.34
Ymax 21.60 21.60 21.60
TL 150.97 164.85 185.45
BF 11.75 21.93 30.78
[Lens specifications]
Surface number RD nd νd
Object surface ∞
1 454.1335 2.500 1.94594 17.98
2 158.8346 5.629 1.81600 46.59
3 -1850.8518 0.200
4 62.5732 5.149 1.81600 46.59
5 111.4228 D5 (variable)
6 * 143.7538 2.000 1.81600 46.59
7 20.1321 9.695
8-48.3009 2.346 1.88300 40.66
9 156.4679 0.200
10 65.6396 6.565 1.80518 25.45
11 -42.2522 2.354
12 -26.3896 1.200 1.69680 55.52
13 -61.8795 D13 (variable)
14 ∞ 1.500 (Aperture S)
15 * 46.9137 2.985 1.81600 46.59
16 79.9069 0.200
17 56.4482 6.543 1.49782 82.57
18 -69.0474 D18 (variable)
19 78.4165 1.300 1.90366 31.27
20 26.6178 9.263 1.59319 67.90
21 -58.5857 D21 (variable)
22 -29.0948 1.200 1.80100 34.92
23 -53.3089 2.957
24 64.8393 6.500 1.48749 70.32
25 -36.2810 D25 (variable)
26 -486.6338 2.667 1.58887 61.13
27 * -77.9833 D27 (variable)
28 208.9420 1.200 1.90366 31.27
29 40.1016 3.903
30 -103.6980 6.199 1.84666 23.80
31 -35.7067 3.104
32 * -19.6292 1.500 1.81600 46.59
33 -40.5502 BF
Image plane ∞
[Aspherical data]
Side 6 κ = 1.0000, A4 = 4.25283E-06, A6 = -2.28156E-09
A8 = -7.12258E-14, A10 = 7.16065E-15, A12 = 0.00000E + 00
Surface 15 κ = 1.0000, A4 = -3.75837E-06, A6 = 9.56813E-10
A8 = -1.31531E-12, A10 = 1.97978E-16, A12 = 0.00000E + 00
Side 27 κ = 1.0000, A4 = 1.00937E-05, A6 = -5.09501E-11
A8 = -1.76649E-12, A10 = 1.58609E-14, A12 = 0.00000E + 00
Side 32 κ = 1.0000, A4 = 1.01091E-05, A6 = 1.61408E-08
A8 = 3.76726E-12, A10 = 1.25182E-13, A12 = 0.00000E + 00
[Lens group data]
Focal length
G1 1 130.092
G2 6 -23.049
G3 14 44.414
G4 19 100.000
G5 22 98.812
G6 26 157.320
G7 28 -42.703
[Variable interval data]
W M T W M T
Infinity Infinity Infinity Infinity Short distance Short distance Short distance
D5 2.000 21.323 36.906 2.000 21.323 36.906
D13 25.662 7.746 2.000 25.662 7.746 2.000
D18 9.597 5.312 1.500 9.597 5.312 1.500
D21 6.192 11.864 21.415 5.303 10.833 20.070
D25 2.000 3.105 2.000 2.411 3.415 2.346
D27 4.901 4.716 2.000 5.379 5.438 2.999
[Conditional expression correspondence value]
Conditional expression (1) f1 / f4 = 1.301
Conditional expression (2) f4 / fw = 4.040
Conditional expression (3) f3 / f4 = 0.444
Conditional expression (4) dP1 / f1 = 0.062
Conditional expression (5) | fF | / ft = 1.907
Conditional expression (6) nN / nP = 1.195
Conditional expression (7) νN / νP = 0.461
Conditional expression (8) f1 / | fRw | = 0.594
Conditional expression (9) 2ωw = 85.12
Conditional expression (10) BFw / fw = 0.475
Conditional expression (11) (rR2 + rR1) / (rR2-rR1) = 2.877

8 (A), 8 (A), and 8 (C) show 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 at infinity focusing, respectively. It is a diagram of various aberrations of. 9 (A), 9 (B), and 9 (C) show 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, at the time of short-distance focusing. It is a diagram of various aberrations of. From each aberration diagram, the variable magnification optical system according to the third embodiment satisfactorily corrects various aberrations from the wide-angle end state to the telephoto end state and has excellent imaging performance, and further, at the time of short-distance focusing. It can be seen that also has excellent imaging performance.

(Fourth Example)
A fourth embodiment will be described with reference to FIGS. 10 to 12 and Table 4. FIG. 10 is a diagram showing a lens configuration of a variable magnification optical system according to a fourth embodiment. 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 an aperture arranged in order from the object side. Aperture S, 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 third lens group having a negative refractive power. It is composed of 6 lens groups G6. When scaling from the wide-angle end state (W) to the telephoto end state (T), the first to sixth lens groups G1 to G6 move in the directions indicated by the arrows in FIG. Change. The lens group including the fifth lens group G5 and the sixth lens group G6 corresponds to the succeeding lens group GR and has a negative refractive power as a whole.

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

The second lens group G2 has a negative meniscus lens L21 having a convex surface facing the object side, a negative lens L22 having a biconcave shape, a positive lens L23 having a biconvex shape, 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 negative meniscus lens L21 has an aspherical lens surface on the object side.

The third lens group G3 is composed of a positive meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32 arranged in order from the object side. The aperture diaphragm S is provided near the object side of the third lens group G3, and moves together with the third lens group G3 at the time of scaling. The positive meniscus lens L31 has an aspherical lens surface on the object side.

The fourth lens group G4 is composed of a junction positive lens of a negative meniscus lens L41 having a convex surface facing the object side and a biconvex positive lens L42.

The fifth lens group G5 is composed of a negative meniscus lens L51 having a concave surface facing the object side, a biconvex positive lens L52, and a positive meniscus lens L53 having a concave surface facing the object side, arranged in order from the object side. Will be done. The positive meniscus lens L53 has an aspherical lens surface on the image side.

The sixth lens group G6 is composed of a positive meniscus lens L61 having a concave surface facing the object side, a negative lens L62 having a concave shape, and a negative meniscus lens L63 having a concave surface facing the object side, which are arranged in order from the object side. Will be done. The negative lens L62 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.

In this embodiment, by moving the fifth lens group G5 to the object side, focusing is performed from a long-distance object to a short-distance object (from an infinity object to a finite-distance object). That is, the fifth lens group G5 corresponds to the in-focus lens group.

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

(Table 4)
[Overall specifications]
Variable ratio 2.75
fRw = -356.649
WMT
f 24.7 50.0 67.9
FNO 2.92 2.92 2.92
2ω 85.08 45.26 33.84
Ymax 21.60 21.60 21.60
TL 139.95 154.92 168.36
BF 11.75 26.42 30.21
[Lens specifications]
Surface number RD nd νd
Object surface ∞
1 500.0000 2.500 1.84666 23.80
2 128.5654 5.629 1.77250 49.62
3 1528.3565 0.200
4 51.0685 4.893 1.81600 46.59
5 84.5957 D5 (variable)
6 * 150.2756 2.000 1.74389 49.53
7 19.5218 9.332
8 -70.5990 1.300 1.83481 42.73
9 68.8663 0.377
10 44.7171 5.665 1.78472 25.64
11 -66.3119 4.463
12 -25.4625 1.300 1.60300 65.44
13 -54.4747 D13 (variable)
14 ∞ 1.500 (Aperture S)
15 * 93.5557 2.758 1.58913 61.15
16 731.3943 0.200
17 45.8800 5.212 1.59319 67.90
18 -126.9127 D18 (variable)
19 57.2400 1.300 1.73800 32.33
20 21.3782 8.742 1.49782 82.57
21 -52.7685 D21 (variable)
22 -23.6692 1.200 1.73800 32.33
23 -59.4644 0.200
24 110.3346 5.800 1.59349 67.00
25 -32.1046 4.444
26 -114.5585 3.326 1.74389 49.53
27 * -41.8456 D27 (variable)
28 -51.0521 2.929 1.94594 17.98
29 -33.3238 0.200
30 * -98.8101 1.500 1.85108 40.12
31 58.4711 6.329
32 -25.4692 1.400 1.69680 55.52
33 -42.7921 BF
Image plane ∞
[Aspherical data]
Side 6 κ = 1.0000, A4 = 4.65692E-06, A6 = -1.64542E-09
A8 = 3.72186E-13, A10 = 4.82369E-15, A12 = 0.00000E + 00
Surface 15 κ = 1.0000, A4 = -3.70657E-06, A6 = 3.18672E-09
A8 = -1.82835E-11, A10 = 3.59863E-14, A12 = 0.00000E + 00
Side 27 κ = 1.0000, A4 = 1.13375E-05, A6 = -1.49475E-08
A8 = 6.38011E-11, A10 = -1.10074E-13, A12 = 0.00000E + 00
Side 30 κ = 1.0000, A4 = -5.84233E-06, A6 = -2.49185E-08
A8 = 2.26680E-11, A10 = -7.54165E-14, A12 = 0.00000E + 00
[Lens group data]
Focal length
G1 1 136.259
G2 6 -23.493
G3 14 44.223
G4 19 90.807
G5 22 53.777
G6 28 -40.364
[Variable interval data]
W M T W M T
Infinity Infinity Infinity Infinity Short distance Short distance Short distance
D5 2.000 16.966 30.403 2.000 16.966 30.403
D13 20.342 6.266 2.000 20.342 6.266 2.000
D18 10.475 3.778 2.048 10.475 3.778 2.048
D21 4.711 14.758 17.000 4.046 13.957 16.055
D27 5.973 2.030 2.000 6.639 2.831 2.945
[Conditional expression correspondence value]
Conditional expression (1) f1 / f4 = 1.501
Conditional expression (2) f4 / fw = 3.669
Conditional expression (3) f3 / f4 = 0.487
Conditional expression (4) dP1 / f1 = 0.060
Conditional expression (5) | fF | / ft = 0.792
Conditional expression (6) nN / nP = 1.160
Conditional expression (7) νN / νP = 0.392
Conditional expression (8) f1 / | fRw | = 0.382
Conditional expression (9) 2ωw = 85.08
Conditional expression (10) BFw / fw = 0.475
Conditional expression (11) (rR2 + rR1) / (rR2-rR1) = 3.941

11 (A), 11 (B), and 11 (C) show 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 diagram of various aberrations of. 12 (A), 12 (B), and 12 (C) show 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, at the time of short-distance focusing. It is a diagram of various aberrations of. From each aberration diagram, the variable magnification optical system according to the fourth embodiment satisfactorily corrects various aberrations from the wide-angle end state to the telephoto end state and has excellent imaging performance, and further, at the time of short-distance focusing. It can be seen that also has excellent imaging performance.

(Fifth Example)
A fifth embodiment will be described with reference to FIGS. 13 to 15 and Table 5. FIG. 13 is a diagram showing a lens configuration of a variable magnification optical system according to a fifth embodiment. 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 an aperture arranged in order from the object side. Aperture S, 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 third lens group having a positive refractive power. It is composed of 6 lens groups G6. When scaling from the wide-angle end state (W) to the telephoto end state (T), the first to sixth lens groups G1 to G6 move in the directions indicated by the arrows in FIG. Change. The lens group including the fifth lens group G5 and the sixth lens group G6 corresponds to the succeeding lens group GR and has a negative refractive power as a whole.

The first lens group G1 includes 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 having a convex surface facing the object side. It is composed of L13. The negative meniscus lens L11 corresponds to the eleventh lens. The positive lens L12 corresponds to the twelfth 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, 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 negative meniscus lens L21 has an aspherical lens surface on the object side.

The third lens group G3 is composed of a positive meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32 arranged in order from the object side. The aperture diaphragm S is provided near the object side of the third lens group G3, and moves together with the third lens group G3 at the time of scaling. The positive meniscus lens L31 has an aspherical lens surface on the object side.

The fourth lens group G4 includes a biconvex positive lens L41, a biconcave negative lens L42, and a biconvex positive lens L43, which are arranged in order from the object side, and a biconvex positive lens. It is composed of a lens L44. The positive lens L41 has an aspherical lens surface on the object side. The positive lens L44 has an aspherical lens surface on the image side.

The fifth lens group G5 is composed of a positive meniscus lens L51 having a concave surface facing the object side, a biconcave negative lens L52, and a biconcave negative lens L53 arranged in order from the object side. The negative lens L53 has an aspherical lens surface on the object side.

The sixth lens group G6 is composed of a biconvex positive lens L61. The image plane I is arranged on the image side of the sixth lens group G6.

In this embodiment, by moving the fifth lens group G5 to the image plane I side, focusing is performed from a long-distance object to a short-distance object (from an infinity object to a finite-distance object). That is, the fifth lens group G5 corresponds to the in-focus lens group.

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

(Table 5)
[Overall specifications]
Variable ratio 2.75
fRw = -45.339
WMT
f 24.7 50.0 67.9
FNO 2.92 2.92 2.92
2ω 85.16 45.24 34.12
Ymax 21.60 21.60 21.60
TL 134.73 154.61 169.45
BF 13.56 26.94 34.84
[Lens specifications]
Surface number RD nd νd
Object surface ∞
1 10957.4900 2.500 1.84666 23.80
2 273.2507 3.923 1.59319 67.90
3 -4164.8091 0.200
4 97.8909 5.850 1.81600 46.59
5 1686.5488 D5 (variable)
6 * 500.0000 2.000 1.67798 54.89
7 19.6217 7.571
8 -119.4257 1.200 1.59319 67.90
9 74.2767 0.211
10 36.8572 5.028 1.85000 27.03
11 146.1931 4.217
12 -25.9063 1.200 1.60300 65.44
13 -48.3220 D13 (variable)
14 ∞ 1.500 (Aperture S)
15 * 31.8609 3.346 1.79504 28.69
16 60.3817 1.288
17 65.3208 3.503 1.49782 82.57
18 -22831.8850 D18 (variable)
19 * 52.1943 4.361 1.82098 42.50
20 -99.8775 0.663
21 -484.1811 1.200 1.85478 24.80
22 19.0497 8.079 1.49782 82.57
23 -86.9834 3.675
24 61.0249 5.155 1.80604 40.74
25 * -60.8291 D25 (variable)
26 -310.5249 2.912 1.94594 17.98
27 -59.5174 0.200
28 -155.6589 1.200 1.77250 49.62
29 30.4299 6.880
30 * -54.7368 1.300 1.95150 29.83
31 317.1233 D31 (variable)
32 72.1520 4.819 1.83481 42.73
33 -315.4491 BF
Image plane ∞
[Aspherical data]
Side 6 κ = 1.0000, A4 = 5.57412E-06, A6 = -5.71627E-09
A8 = 9.08385E-12, A10 = -4.74214E-15, A12 = 0.00000E + 00
Fifteenth surface κ = 1.0000, A4 = -5.90450E-06, A6 = 3.98445E-09
A8 = -4.29920E-11, A10 = 9.10161E-14, A12 = 0.00000E + 00
Surface 19 κ = 1.0000, A4 = -5.71112E-06, A6 = -6.16170E-10
A8 = 2.42198E-11, A10 = -5.71940E-14, A12 = 0.00000E + 00
Surface 25 κ = 1.0000, A4 = 2.37352E-06, A6 = -6.63258E-09
A8 = -2.39966E-11, A10 = 1.99908E-14, A12 = 0.00000E + 00
Side 30 κ = 1.0000, A4 = -6.17314E-06, A6 = -3.26346E-08
A8 = 1.332620E-10, A10 = -6.33629E-13, A12 = 0.00000E + 00
[Lens group data]
Focal length
G1 1 139.410
G2 6 -23.353
G3 14 51.116
G4 19 31.271
G5 26 -24.892
G6 32 70.741
[Variable interval data]
W M T W M T
Infinity Infinity Infinity Infinity Short distance Short distance Short distance
D5 2.000 21.443 31.758 2.000 21.443 31.758
D13 19.908 6.376 2.000 19.908 6.376 2.000
D18 9.100 3.184 2.000 9.100 3.184 2.000
D25 3.162 2.189 2.000 3.569 2.602 2.454
D31 3.023 10.499 12.881 2.616 10.087 12.426
[Conditional expression correspondence value]
Conditional expression (1) f1 / f4 = 4.458
Conditional expression (2) f4 / fw = 1.263
Conditional expression (3) f3 / f4 = 1.635
Conditional expression (4) dP1 / f1 = 0.046
Conditional expression (5) | fF | / ft = 0.367
Conditional expression (6) nN / nP = 1.238
Conditional expression (7) νN / νP = 0.300
Conditional expression (8) f1 / | fRw | = 3.075
Conditional expression (9) 2ωw = 85.16
Conditional expression (10) BFw / fw = 0.548
Conditional expression (12) (rR2 + rR1) / (rR2-rR1) = 0.628

14 (A), 14 (B), and 14 (C) show 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 at infinity focusing, respectively. It is a diagram of various aberrations of. 15 (A), 15 (B), and 15 (C) show 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, at the time of short-distance focusing. It is a diagram of various aberrations of. From each aberration diagram, the variable magnification optical system according to the fifth embodiment satisfactorily corrects various aberrations from the wide-angle end state to the telephoto end state and has excellent imaging performance, and further, at the time of short-distance focusing. It can be seen that also has excellent imaging performance.

(6th Example)
The sixth embodiment will be described with reference to FIGS. 16 to 18 and Table 6. FIG. 16 is a diagram showing a lens configuration of a variable magnification optical system according to a sixth embodiment. 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 an aperture arranged in order from the object side. Aperture S, 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 third lens group having a positive refractive power. It is composed of a 6-lens group G6 and a 7th lens group G7 having a positive refractive power. When scaling from the wide-angle end state (W) to the telephoto end state (T), the first to seventh lens groups G1 to G7 move in the directions indicated by the arrows in FIG. Change. The lens group including the fifth lens group G5, the sixth lens group G6, and the seventh lens group G7 corresponds to the succeeding lens group GR, and has a negative refractive power as a whole.

The first lens group G1 is a junction negative lens of a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side, which are arranged in order from the object side, and a convex surface facing the object side. It is composed of a positive meniscus lens L13. The negative meniscus lens L11 corresponds to the eleventh lens. The positive meniscus lens L12 corresponds to the twelfth 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, 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 negative meniscus lens L21 has an aspherical lens surface on the object side.

The third lens group G3 is composed of a positive meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32 arranged in order from the object side. The aperture diaphragm S is provided near the object side of the third lens group G3, and moves together with the third lens group G3 at the time of scaling. The positive meniscus lens L31 has an aspherical lens surface on the object side.

The fourth lens group G4 includes a biconvex positive lens L41, a biconcave negative lens L42, and a biconvex positive lens L43, which are arranged in order from the object side, and a biconvex positive lens. It is composed of a lens L44. The positive lens L41 has an aspherical lens surface on the object side. The positive lens L44 has an aspherical lens surface on the image side.

The fifth lens group G5 is composed of a positive meniscus lens L51 having a concave surface facing the object side, a biconcave negative lens L52, and a biconcave negative lens L53 arranged in order from the object side. The negative lens L53 has an aspherical lens surface on the object side.

The sixth lens group G6 is composed of a positive meniscus lens L61 with a convex surface facing the object side.

The seventh lens group G7 is composed of a biconvex positive lens L71. The image plane I is arranged on the image side of the seventh lens group G7.

In this embodiment, by moving the fifth lens group G5 to the image plane I side, focusing is performed from a long-distance object to a short-distance object (from an infinity object to a finite-distance object). That is, the fifth lens group G5 corresponds to the in-focus lens group.

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

(Table 6)
[Overall specifications]
Variable ratio 2.74
fRw = -40.687
WMT
f 24.8 50.0 67.9
FNO 2.96 2.98 2.99
2ω 85.16 45.20 34.12
Ymax 21.60 21.60 21.60
TL 138.57 158.72 174.45
BF 13.13 25.93 34.76
[Lens specifications]
Surface number RD nd νd
Object surface ∞
1 800.0000 2.500 1.84666 23.80
2 214.4014 3.846 1.59319 67.90
3 1317.1215 0.200
4 112.4262 5.452 1.81600 46.59
5 6769.9563 D5 (variable)
6 * 500.0000 2.000 1.67798 54.89
7 20.1483 7.488
8 -122.7141 1.200 1.59319 67.90
9 65.7886 0.272
10 36.9186 6.199 1.85000 27.03
11 167.8314 4.151
12 -26.0907 1.200 1.60300 65.44
13 -47.5468 D13 (variable)
14 ∞ 1.500 (Aperture S)
15 * 34.4078 3.172 1.79504 28.69
16 61.0992 1.040
17 57.2334 3.808 1.49782 82.57
18 -5887.8063 D18 (variable)
19 * 56.4489 4.200 1.82098 42.50
20 -110.1792 0.505
21 -291.5983 1.200 1.85478 24.80
22 21.3003 9.632 1.49782 82.57
23 -65.8810 3.027
24 55.5374 5.156 1.80604 40.74
25 * -64.8934 D25 (variable)
26 -368.5041 2.887 1.94594 17.98
27 -62.4504 0.200
28 -158.4306 1.200 1.77250 49.62
29 31.1763 6.060
30 * -91.4544 1.300 1.95150 29.83
31 81.4249 D31 (variable)
32 57.0897 2.149 1.80518 25.45
33 69.0085 D33 (variable)
34 73.7084 4.702 1.64000 60.19
35 -314.5384 BF
Image plane ∞
[Aspherical data]
Side 6 κ = 1.0000, A4 = 4.89442E-06, A6 = -5.03173E-09
A8 = 9.04508E-12, A10 = -5.83062E-15, A12 = 0.00000E + 00
Fifteenth surface κ = 1.0000, A4 = -5.12384E-06, A6 = 3.61548E-09
A8 = -3.66003E-11, A10 = 7.76731E-14, A12 = 0.00000E + 00
Surface 19 κ = 1.0000, A4 = -5.21485E-06, A6 = -8.93869E-10
A8 = 2.28848E-11, A10 = -5.347080E-14, A12 = 0.00000E + 00
Surface 25 κ = 1.0000, A4 = 3.45860E-06, A6 = -6.25344E-09
A8 = -1.37950E-11, A10 = 2.51017E-14, A12 = 0.00000E + 00
Side 30 κ = 1.0000, A4 = -6.74203E-06, A6 = -2.42770E-08
A8 = 5.92492E-11, A10 = -3.49332E-13, A12 = 0.00000E + 00
[Lens group data]
Focal length
G1 1 152.425
G2 6 -24.007
G3 14 52.775
G4 19 30.001
G5 26 -24.147
G6 32 379.967
G7 34 93.748
[Variable interval data]
W M T W M T
Infinity Infinity Infinity Infinity Short distance Short distance Short distance
D5 2.000 22.083 33.118 2.000 22.083 33.118
D13 20.464 6.484 2.000 20.464 6.484 2.000
D18 9.842 3.320 2.000 9.842 3.320 2.000
D25 2.978 2.225 2.053 3.339 2.586 2.447
D31 2.915 10.198 13.200 2.555 9.837 12.806
D33 1.000 2.234 1.084 1.000 2.234 1.084
[Conditional expression correspondence value]
Conditional expression (1) f1 / f4 = 5.081
Conditional expression (2) f4 / fw = 1.212
Conditional expression (3) f3 / f4 = 1.759
Conditional expression (4) dP1 / f1 = 0.042
Conditional expression (5) | fF | / ft = 0.356
Conditional expression (6) nN / nP = 1.238
Conditional expression (7) νN / νP = 0.300
Conditional expression (8) f1 / | fRw | = 3.746
Conditional expression (9) 2ωw = 85.16
Conditional expression (10) BFw / fw = 0.530
Conditional expression (12) (rR2 + rR1) / (rR2-rR1) = 0.620

17 (A), 17 (B), and 17 (C) are at infinity focusing 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 diagram of various aberrations of. 18 (A), 18 (B), and 18 (C) are short-distance focusing 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 diagram of various aberrations of. From each aberration diagram, the variable magnification optical system according to the sixth embodiment satisfactorily corrects various aberrations from the wide-angle end state to the telephoto end state and has excellent imaging performance, and further, at the time of short-distance focusing. It can be seen that also has excellent imaging performance.

(7th Example)
A seventh embodiment will be described with reference to FIGS. 19 to 21 and Table 7. FIG. 19 is a diagram showing a lens configuration of a variable magnification optical system according to a seventh embodiment. 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 refractive power, and an aperture arranged in order from the object side. Aperture S, 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 third lens group having a positive refractive power. It is composed of a 6-lens group G6 and a 7th lens group G7 having a negative refractive power. When scaling from the wide-angle end state (W) to the telephoto end state (T), the first to seventh lens groups G1 to G7 move in the directions indicated by the arrows in FIG. Change. The lens group including the fifth lens group G5, the sixth lens group G6, and the seventh lens group G7 corresponds to the succeeding lens group GR and has a positive refractive power as a whole.

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

The second lens group G2 has a negative meniscus lens L21 having a convex surface facing the object side, a negative lens L22 having a biconcave shape, a positive lens L23 having a biconvex shape, 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 negative meniscus lens L21 has an aspherical lens surface on the object side.

The third lens group G3 is composed of a positive meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32 arranged in order from the object side. The aperture diaphragm S is provided near the object side of the third lens group G3, and moves together with the third lens group G3 at the time of scaling. The positive meniscus lens L31 has an aspherical lens surface on the object side.

The fourth lens group G4 is composed of a junction positive lens of a negative meniscus lens L41 having a convex surface facing the object side and a biconvex positive lens L42.

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

The sixth lens group G6 is composed of a positive meniscus lens L61 with a concave surface facing the object side. The positive meniscus lens L61 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, a negative lens L72 having a concave shape, and a negative meniscus lens L73 having a concave surface facing the object side, which are arranged in order from the object side. NS. The image plane I is arranged on the image side of the seventh lens group G7. The negative lens L72 has an aspherical lens surface on the object side.

In this embodiment, by moving the fifth lens group G5 and the sixth lens group G6 independently to the object side, focusing from a long-distance object to a short-distance object (from an infinity object to a finite-distance object) is achieved. Will be done. That is, the fifth lens group G5 corresponds to the first focusing lens group, and the sixth lens group G6 corresponds to the second focusing lens group.

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

(Table 7)
[Overall specifications]
Variable ratio 2.74
fRw = 4055.914
WMT
f 24.8 50.0 67.9
FNO 2.92 2.92 2.92
2ω 85.10 45.24 33.84
Ymax 21.60 21.60 21.60
TL 139.31 158.27 168.76
BF 11.75 23.48 28.76
[Lens specifications]
Surface number RD nd νd
Object surface ∞
1 189.0188 2.500 1.84666 23.80
2 98.2637 5.200 1.75500 52.33
3 281.1360 0.200
4 58.7593 5.700 1.77250 49.62
5 135.0000 D5 (variable)
6 * 221.1138 2.000 1.74389 49.53
7 18.6091 9.662
8 -58.7660 1.300 1.77250 49.62
9 58.7660 0.506
10 39.8268 6.400 1.72825 28.38
11 -48.5880 1.773
12 -26.6513 1.300 1.61800 63.34
13 -70.7180 D13 (variable)
14 ∞ 1.702 (Aperture S)
15 * 71.3000 2.500 1.69370 53.32
16 121.5261 0.202
17 38.6117 5.900 1.59319 67.90
18 -111.3842 D18 (variable)
19 66.4297 1.300 1.73800 32.33
20 19.7070 9.700 1.49782 82.57
21 -49.1811 D21 (variable)
22 -23.7160 1.200 1.72047 34.71
23 -55.5303 0.200
24 103.5406 5.980 1.59349 67.00
25 -32.7186 D25 (variable)
26 -75.1626 3.736 1.79189 45.04
27 * -39.1303 D27 (variable)
28 -44.6016 3.000 1.94594 17.98
29 -32.9994 0.201
30 * -101.4301 1.500 1.85207 40.15
31 85.4850 7.927
32 -25.8904 1.400 1.58913 61.22
33 -45.0397 BF
Image plane ∞
[Aspherical data]
Side 6 κ = 1.0000, A4 = 5.47971E-06, A6 = -6.22095E-09
A8 = 1.44104E-11, A10 = -2.08855E-14, A12 = 2.01910E-17
Surface 15 κ = 1.0000, A4 = -4.50985E-06, A6 = 2.81159E-10
A8 = -2.663745E-12, A10 = -4.80538E-15, A12 = 0.00000E + 00
Side 27 κ = 1.0000, A4 = 1.009182E-05, A6 = -2.25976E-08
A8 = 1.43325E-10, A10 = -4.96895E-13, A12 = 6.77820E-16
Side 30 κ = 1.0000, A4 = -2.1929E-06, A6 = -2.44256E-08
A8 = 6.38954E-11, A10 = -1.65927E-13, A12 = 0.00000E + 00
[Lens group data]
Focal length
G1 1 118.121
G2 6 -21.898
G3 14 41.497
G4 19 109.585
G5 22 123.527
G6 26 98.560
G7 28 -47.807
[Variable interval data]
W M T W M T
Infinity Infinity Infinity Infinity Short distance Short distance Short distance
D5 1.800 21.061 29.930 1.800 21.061 29.930
D13 19.119 6.127 2.000 19.119 6.127 2.000
D18 9.354 3.967 1.500 9.354 3.967 1.500
D21 5.286 14.229 18.845 4.337 12.953 17.517
D25 2.861 3.580 2.713 3.291 4.145 3.115
D27 6.143 2.841 2.028 6.662 3.552 2.955
[Conditional expression correspondence value]
Conditional expression (1) f1 / f4 = 1.078
Conditional expression (2) f4 / fw = 4.428
Conditional expression (3) f3 / f4 = 0.379
Conditional expression (4) dP1 / f1 = 0.065
Conditional expression (5) | fF | / ft = 1.819
Conditional expression (6) nN / nP = 1.160
Conditional expression (7) νN / νP = 0.392
Conditional expression (8) f1 / | fRw | = 0.029
Conditional expression (9) 2ωw = 85.10
Conditional expression (10) BFw / fw = 0.475
Conditional expression (11) (rR2 + rR1) / (rR2-rR1) = 3.704

20 (A), 20 (B), and 20 (C) are at infinity focusing 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 diagram of various aberrations of. 21 (A), 21 (C), and 21 (C) show 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, at the time of short-distance focusing. It is a diagram of various aberrations of. From each aberration diagram, the variable magnification optical system according to the seventh embodiment satisfactorily corrects various aberrations from the wide-angle end state to the telephoto end state and has excellent imaging performance, and further, at the time of short-distance focusing. It can be seen that also has excellent imaging performance.

According to each embodiment, it is possible to realize high-speed and quiet autofocus without increasing the size of the lens barrel, and the fluctuation of aberration at the time of scaling from the wide-angle end state to the telephoto end state and infinity. It is possible to realize a variable magnification optical system that suppresses fluctuations in aberrations when focusing from an object to a short-range object.

Here, the above-mentioned first to seventh embodiments show one specific example of the present embodiment, and the present embodiment 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.

Numerical examples of the variable magnification optical system show the one having a 6-group configuration and the one having a 7-group configuration, but the present application is not limited to this, and a variable-magnification optical system having another group configuration (for example, 8 groups, etc.) is configured. You can also do it. 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 magnification change.

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 deviated, the depiction performance is less deteriorated, which is preferable.

When the lens surface is aspherical, the aspherical surface is an aspherical surface formed by grinding, a glass mold aspherical surface formed by forming glass into an aspherical shape, or a composite aspherical surface formed by forming resin on the glass surface into an aspherical 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.

The aperture diaphragm is preferably arranged between the second lens group and the third lens group, but the role may be substituted by the frame of the lens without providing the member as the aperture diaphragm.

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

G1 1st lens group G2 2nd lens group G3 3rd lens group G4 4th lens group G5 5th lens group G6 6th lens group G7 7th lens group I image plane S Aperture aperture

Claims (18)

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 third lens group having a positive refractive power arranged in order from the object side. It has 4 lens groups and a succeeding lens group.
At the time of scaling, the distance between adjacent lens groups changes,
The subsequent lens group has a focusing lens group that moves during focusing, and has a focusing lens group.
A variable magnification optical system that satisfies the following conditional expression.
0.80 <f1 / f4 <5.10
1.20 <f4 / fw <6.80
However, f1: the focal length of the first lens group f4: the focal length of the fourth lens group ww: the focal length of the variable magnification optical system in the wide-angle end state. The variable magnification optical system according to claim 1, which satisfies the following conditional expression.
0.20 <f3 / f4 <2.50
However, f3: the focal length of the third lens group The first lens group includes an eleventh lens having a negative refractive power and a twelfth lens having a positive refractive power arranged in order from the object side.
The variable magnification optical system according to claim 1 or 2, which satisfies the following conditional expression.
0.010 <dP1 / f1 <0.075
However, dP1: the sum of the center thickness of the 11th lens and the center thickness of the 12th lens. The variable magnification optical system according to any one of claims 1 to 3, wherein the focusing lens group comprises three or less single lenses. The variable magnification optical system according to any one of claims 1 to 4, wherein at least one of the focusing lens groups has a single lens having a negative refractive power. The variable magnification optical system according to any one of claims 1 to 5, wherein the focusing lens group is arranged on the image side of the aperture diaphragm. The variable magnification optical system according to any one of claims 1 to 6, wherein at least four lens groups are arranged on the image side of the aperture diaphragm. The variable magnification optical system according to any one of claims 1 to 7, which satisfies the following conditional expression.
0.20 << | fF | / ft <4.00
However, fF: the focal length of the focusing lens group having the strongest refractive power among the focusing lens groups ft: the focal length of the variable magnification optical system in the telephoto end state. The variable magnification optical system according to any one of claims 1 to 8, wherein the fourth lens group includes a junction lens of a negative lens and a positive lens. The fourth lens group has a junction lens of a negative lens and a positive lens.
The variable magnification optical system according to any one of claims 1 to 9, which satisfies the following conditional expression.
1.00 <nN / nP <1.35
However, nN: the refractive index of the negative lens in the bonded lens nP: the refractive index of the positive lens in the bonded lens. The fourth lens group has a junction lens of a negative lens and a positive lens.
The variable magnification optical system according to any one of claims 1 to 10, which satisfies the following conditional expression.
0.20 <νN / νP <0.85
However, νN: Abbe number of the negative lens in the junction lens νP: Abbe number of the positive lens in the junction lens The variable magnification optical system according to any one of claims 1 to 11, which satisfies the following conditional expression.
f1 / | fRw | <5.00
However, fRw: the focal length of the subsequent lens group in the wide-angle end state. The variable magnification optical system according to any one of claims 1 to 12, which satisfies the following conditional expression.
2ωw> 75 °
However, ωw: half 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 13, which satisfies the following conditional expression.
0.10 <BFw / fw <1.00
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. The variable magnification optical system according to any one of claims 1 to 14, which satisfies the following conditional expression when the focusing lens group has a positive refractive power.
0.00 <(rR2 + rR1) / (rR2-rR1) <8.00
However, rR1: the radius of curvature of the lens surface on the object side of the lens arranged on the most image side of the variable magnification optical system rR2: the lens surface on the image side of the lens arranged on the most image side of the variable magnification optical system. curvature radius The variable magnification optical system according to any one of claims 1 to 14, which satisfies the following conditional expression when the focusing lens group has a negative refractive power.
-4.00 <(rR2 + rR1) / (rR2-rR1) <4.00
However, rR1: the radius of curvature of the lens surface on the object side of the lens arranged on the most image side of the variable magnification optical system rR2: the lens surface on the image side of the lens arranged on the most image side of the variable magnification optical system. curvature radius An optical device including the variable magnification optical system according to any one of claims 1 to 16. 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 third lens group having a positive refractive power arranged in order from the object side. A method for manufacturing a variable magnification optical system having four lens groups and a succeeding lens group.
At the time of scaling, the distance between adjacent lens groups changes,
The subsequent lens group has a focusing lens group that moves during focusing, and has a focusing lens group.
To satisfy the following conditional expression
A method for manufacturing a variable magnification optical system in which each lens is arranged in a lens barrel.
0.80 <f1 / f4 <5.10
1.20 <f4 / fw <6.80
However, f1: the focal length of the first lens group f4: the focal length of the fourth lens group ww: the focal length of the variable magnification optical system in the wide-angle end state.

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