JP2021002063A - Zoom optical system, optical device, and image capturing device - Google Patents

Abstract

To provide a zoom optical system which has a focusing lens group with sufficiently reduced weight and offers good optical performance, and to provide an optical device and image capturing device using the same.SOLUTION: A zoom optical system provided herein consists substantially of five lens groups comprising, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power, and is configured such that distances between adjacent lens groups change while zooming and that the fourth lens group moves while shifting focus from an object at infinity to a nearby object. The third lens group has an A lens group that satisfies the following conditional expression: 1.10<fvr/fTM2<2.00, where fvr represents a focal length of the A lens group and fTM2 represents a focal length of the third lens group at the telephoto end.SELECTED DRAWING: Figure 1

Description

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

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).

Japanese Patent Application Laid-Open No. 4-293007

However, in the conventional variable magnification optical system, the weight reduction of the focusing lens group has been insufficient.

The variable magnification optical system according to the present invention includes a first lens group having a positive refractive force, a second lens group having a negative refractive force, and a third lens group having a positive refractive force in order from the object side. It consists of substantially five lens groups, a fourth lens group having a negative refractive power and a fifth lens group having a positive refractive power, and the distance between each lens group changes at the time of magnification change, and is infinite. When focusing from a distant object to a short-range object, the fourth lens group moves, and the third lens group has an A lens group that satisfies the following conditional expression.

1.10 <fvr / fTM2 <2.00
However, fvr: focal length of the A lens group fTM2; focal length of the third lens group in the telephoto end state.

The optical device according to the present invention is configured to include the variable magnification optical system.

The imaging apparatus according to the present invention includes the variable magnification optical system and an imaging unit that captures an image formed by the variable magnification optical system.

It is a figure which shows the lens structure of the variable magnification optical system which concerns on 1st Example of this Embodiment. FIG. 2A is a diagram of various aberrations at infinity focusing in the wide-angle end state of the variable magnification optical system according to the first embodiment, and FIG. 2B shows blur correction for rotational blur of 0.30 °. It is a meridional lateral aberration diagram (coma aberration diagram) at the time of performing. It is a diagram of various aberrations at the time of focusing at infinity in the intermediate focal length state of the variable magnification optical system according to the first embodiment. FIG. 4A is a diagram of various aberrations at infinity focusing in the telephoto end state of the variable magnification optical system according to the first embodiment, and FIG. 4B is blur correction for rotational blur of 0.20 °. It is a meridional transverse aberration diagram at the time of performing. 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 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 of this Embodiment. FIG. 7 (a) is a diagram of various aberrations at infinity focusing in the wide-angle end state of the variable magnification optical system according to the second embodiment, and FIG. 7 (b) is a blur correction for rotational blur of 0.30 °. It is a meridional transverse aberration diagram at the time of performing. It is a diagram of various aberrations at the time of focusing at infinity in the intermediate focal length state of the variable magnification optical system according to the second embodiment. FIG. 9A is an aberration diagram at the time of focusing at infinity in the telephoto end state of the variable magnification optical system according to the second embodiment, and FIG. 9B is a blur correction for a rotational blur of 0.20 °. It is a meridional transverse aberration diagram at the time of performing. 10 (a), 10 (b), and 10 (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 of this Embodiment. FIG. 12 (a) is a diagram of various aberrations at infinity focusing in the wide-angle end state of the variable magnification optical system according to the third embodiment, and FIG. 12 (b) is a blur correction for rotational blur of 0.30 °. It is a meridional transverse aberration diagram at the time of performing. It is a diagram of various aberrations at the time of focusing at infinity in the intermediate focal length state of the variable magnification optical system according to the third embodiment. FIG. 14A is a diagram of various aberrations at infinity focusing in the telephoto end state of the variable magnification optical system according to the third embodiment, and FIG. 14B is a blur correction for a rotational blur of 0.20 °. It is a meridional transverse aberration diagram at the time of performing. 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 third 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 4th Example of this Embodiment. FIG. 17 (a) is a diagram of various aberrations at infinity focusing in the wide-angle end state of the variable magnification optical system according to the fourth embodiment, and FIG. 17 (b) shows blur correction for rotational blur of 0.30 °. It is a meridional transverse aberration diagram at the time of performing. It is a diagram of various aberrations at the time of focusing at infinity in the intermediate focal length state of the variable magnification optical system according to the fourth embodiment. FIG. 19A is a diagram of various aberrations at infinity focusing in the telephoto end state of the variable magnification optical system according to the fourth embodiment, and FIG. 19B is a blur correction for a rotational blur of 0.20 °. It is a meridional transverse aberration diagram at the time of performing. 20 (a), 20 (b), and 20 (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. It is a figure which shows the lens structure of the variable magnification optical system which concerns on 5th Example of this Embodiment. FIG. 22A is a diagram of various aberrations at infinity focusing in the wide-angle end state of the variable magnification optical system according to the fifth embodiment, and FIG. 22B is a blurring with respect to a rotational blur of 0.30 °. It is a meridional lateral aberration diagram at the time of correction. It is a diagram of various aberrations at the time of infinity focusing in the intermediate focal length state of the variable magnification optical system according to the fifth embodiment. FIG. 24A is a diagram of various aberrations at infinity focusing in the telephoto end state of the variable magnification optical system according to the fifth embodiment, and FIG. 24B is a blurring with respect to a rotational blur of 0.20 °. It is a meridional lateral aberration diagram at the time of correction. 25 (a), 25 (b), and 25 (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. 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, the optical device, and the imaging device of the present embodiment will be described with reference to the drawings.
As an example of the variable magnification optical system (zoom lens) ZL according to the present embodiment, the variable magnification optical system ZL (1) has a front lens group GFS having a positive refractive force in order from the object side, as shown in FIG. The M1 lens group GM1 having a negative refractive force, the M2 lens group GM2 having a positive refractive force, and the RN lens group GRN having a negative refractive force, and the front lens group GFS at the time of magnification change. The distance between the M1 lens group GM1 and the M1 lens group GM1 and the M2 lens group GM2 changes, the distance between the M2 lens group GM2 and the RN lens group GRN changes, and an object at a short distance from an infinity object. At the time of focusing on, the RN lens group GRN moves, and the M2 lens group GM2 has an A lens group that satisfies the following conditional expression (1).

1.10 <fvr / fTM2 <2.00 ... (1)
However,
fvr: Focal length of the A lens group fTM2: Focal length of the M2 lens group GM2 in the telephoto end state

The variable magnification optical system ZL according to the present embodiment includes the variable magnification optical system ZL (2) shown in FIG. 6, the variable magnification optical system ZL (3) shown in FIG. 11, and the variable magnification optical system ZL shown in FIG. 4) or the variable magnification optical system ZL (5) shown in FIG. 21 may be used.

The variable magnification optical system of the present embodiment has at least four lens groups, and when the magnification is changed from the wide-angle end state to the telephoto end state, the distance between each lens group is changed to obtain good aberration correction at the time of change. Can be planned. Further, by focusing on the RN lens group GRN, the RN lens group GRN, that is, the focusing lens group can be reduced in size and weight.

The above conditional expression (1) defines the ratio between the focal length of the A lens group and the focal length of the M2 lens group GM2 in the telephoto end state. By satisfying this conditional equation (1), fluctuations in various aberrations such as spherical aberration when scaling from the wide-angle end to the telephoto end, and eccentric coma aberration when blur correction is performed, etc. It is possible to suppress the occurrence of various aberrations.

When the corresponding value of the conditional expression (1) of the variable magnification optical system of the present embodiment exceeds the upper limit value, the refractive power of the M2 lens group GM2 in the telephoto end state becomes strong, and when the magnification is changed from the wide-angle end to the telephoto end. It becomes difficult to suppress fluctuations in various aberrations such as spherical aberration. By setting the upper limit value of the conditional expression (1) to 1.95, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, it is preferable to set the upper limit value of the conditional expression (1) to 1.90.

On the other hand, when the corresponding value of the conditional expression (1) of the variable magnification optical system of the present embodiment is less than the lower limit value, the refractive power of the A lens group becomes stronger, including eccentric coma aberration when blur correction is performed. It becomes difficult to suppress the occurrence of various aberrations. By setting the lower limit value of the conditional expression (1) to 1.15, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of this embodiment, it is preferable to set the lower limit value of the conditional expression (1) to 1.20.

According to the variable magnification optical system according to the present embodiment, by reducing the size and weight of the focusing lens group, high-speed AF and quietness during AF are realized without increasing the size of the lens barrel, and a wide angle is achieved. Aberration fluctuations during scaling from the end state to the telephoto end state and aberration fluctuations during focusing from an infinity object to a short-range object can be satisfactorily suppressed. Further, the same effect can be obtained by the manufacturing method of the optical device, the imaging device, and the variable magnification optical system according to the present embodiment.

In the variable magnification optical system according to the present embodiment, it is preferable that the front lens group GFS is moved toward the object when the magnification is changed from the wide-angle end state to the telephoto end state. As a result, the total length of the lens can be shortened in the wide-angle end state, and the variable magnification optical system can be miniaturized.

In the variable magnification optical system according to the present embodiment, it is desirable that the lens group closest to the object side in the M1 lens group GM1 is fixed to the image plane when the magnification is changed from the wide-angle end state to the telephoto end state. .. As a result, performance deterioration due to manufacturing errors can be suppressed and mass productivity can be ensured.

In the variable magnification optical system according to the present embodiment, the A lens group is preferably composed of a lens having a negative refractive power and a lens having a positive refractive power in this order from the object side.

It is desirable that the variable magnification optical system of the present embodiment having the A lens group satisfies the following conditional expression (2).

1.00 <nvrN / nvrP <1.25 ... (2)
However,
nvrN: Refractive index of a lens having a negative refractive power in the A lens group nvrP: Refractive index of a lens having a positive refractive power in the A lens group

Conditional expression (2) defines the ratio of the refractive index of the lens having a negative refractive power in the A lens group to the refractive index of the lens having a positive refractive power in the A lens group. By satisfying this conditional expression (2), it is possible to effectively suppress performance deterioration when blur correction is performed by the A lens group.

When the corresponding value of the conditional expression (2) exceeds the upper limit value, the refractive index of the lens having a positive refractive power in the A lens group becomes low, and eccentric coma aberration that occurs when blur correction is performed occurs. It becomes excessive and difficult to correct. By setting the upper limit value of the conditional expression (2) to 1.22, the effect of the present embodiment can be made more reliable. In order to make the effect of this embodiment more certain, it is preferable to set the upper limit value of the conditional expression (2) to 1.20.

When the corresponding value of the conditional expression (2) is less than the lower limit value, the refractive index of the lens having a negative refractive power in the A lens group becomes low, and the eccentric coma aberration at the time of blur correction is corrected. It will be difficult. By setting the lower limit value of the conditional expression (2) to 1.03, the effect of the present embodiment can be made more reliable. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit value of the conditional expression (2) to 1.05.

It is desirable that the variable magnification optical system having the A lens group also satisfies the following conditional expression (3).

0.30 <νvrN / νvrP <0.90 ... (3)
However,
νvrN: Abbe number of lenses having a negative refractive power in the A lens group νvrP: Abbe number of lenses having a positive refractive power in the A lens group

Conditional expression (3) defines the ratio of the Abbe number of a lens having a negative refractive power in the A lens group to the Abbe number of a lens having a positive refractive power in the A lens group. By satisfying this conditional expression (3), it is possible to effectively suppress performance deterioration when blur correction is performed.

When the corresponding value of the conditional expression (3) exceeds the upper limit value, the Abbe number of the lens having a positive refractive power in the A lens group becomes small, and it becomes difficult to correct the chromatic aberration generated when the blur correction is performed. .. By setting the upper limit value of the conditional expression (3) to 0.85, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of the present embodiment, it is preferable to set the upper limit value of the conditional expression (3) to 0.80.

When the corresponding value of the conditional expression (3) is less than the lower limit value, the Abbe number of the lens having a negative refractive power in the A lens group becomes small, and it becomes difficult to correct the chromatic aberration generated when the blur correction is performed. .. By setting the lower limit value of the conditional expression (3) to 0.35, the effect of the present embodiment can be made more reliable. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit value of the conditional expression (3) to 0.40.

In the variable magnification optical system according to the present embodiment, it is desirable that the following conditional expression (4) is satisfied.

0.15 <(-fTM1) / f1 <0.35 ... (4)
However,
fTM1: Focal length of M1 lens group GM1 in the telephoto end state f1: Focal length of front lens group GFS

Conditional expression (4) defines the ratio between the focal length of the M1 lens group GM1 and the focal length of the front lens group GFS in the telephoto end state. By satisfying this conditional equation (4), it is possible to suppress fluctuations in various aberrations such as spherical aberration when scaling from the wide-angle end to the telephoto end.

When the corresponding value of the conditional expression (4) exceeds the upper limit value, the refractive power of the front lens group GFS becomes stronger, and various aberrations such as spherical aberration at the time of scaling from the wide-angle end to the telephoto end are corrected. Becomes difficult. By setting the upper limit value of the conditional expression (4) to 0.33, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit value of the conditional expression (4) to 0.31.

When the corresponding value of the conditional expression (4) is less than the lower limit value, the refractive power of the M1 lens group GM1 becomes stronger, and fluctuations of various aberrations such as spherical aberration at the time of scaling from the wide-angle end to the telephoto end are suppressed. Becomes difficult. By setting the lower limit value of the conditional expression (4) to 0.16, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit value of the conditional expression (4) to 0.17.

In the variable magnification optical system according to the present embodiment, it is desirable that the following conditional expression (5) is satisfied.

0.20 <fTM2 / f1 <0.40 ... (5)
However,
f1: Focal length of front lens group GFS

Conditional expression (5) defines the ratio of the focal length of the M2 lens group GM2 to the focal length of the front lens group GFS in the telephoto end state. By satisfying this conditional expression (5), it is possible to suppress fluctuations in various aberrations such as spherical aberration when scaling from the wide-angle end to the telephoto end.

When the corresponding value of the conditional expression (5) exceeds the upper limit value, the refractive power of the front lens group GFS becomes stronger, and various aberrations such as spherical aberration at the time of scaling from the wide-angle end to the telephoto end are corrected. Becomes difficult. By setting the upper limit value of the conditional expression (5) to 0.37, the effect of the present embodiment can be made more reliable. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value of the conditional expression (5) to 0.34.

When the corresponding value of the conditional expression (5) is less than the lower limit value, the refractive power of the M2 lens group GM2 becomes stronger, and fluctuations of various aberrations such as spherical aberration at the time of scaling from the wide-angle end to the telephoto end are suppressed. Becomes difficult. By setting the lower limit value of the conditional expression (5) to 0.22, the effect of the present embodiment can be made more reliable. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit value of the conditional expression (5) to 0.24.

In the variable magnification optical system according to the present embodiment, it is preferable that the A lens group is a vibration-proof lens that can move in a direction orthogonal to the optical axis in order to correct the image formation position displacement due to camera shake or the like. As a result, it is possible to effectively suppress performance deterioration when blur correction is performed.

In the variable magnification optical system according to the present embodiment, it is preferable to have a negative meniscus lens with a concave surface facing the object side adjacent to the image side of the RN lens group GRN. Further, a lens having a negative refractive power and a lens having a positive refractive power may be provided in order from the object side adjacent to the image side of the RN lens group GRN. As a result, various aberrations such as coma can be effectively corrected.

In the variable magnification optical system according to the present embodiment, it is preferable to satisfy the following conditional expression (6).

0.70 <(-fN) /fP <2.00 ... (6)
However,
fN: Focal length of the lens with the strongest negative refractive power among the lenses adjacent to the image side of the RN lens group GRN fP: The strongest positive refractive power among the lenses adjacent to the image side of the RN lens group GRN Focal length of the lens

The above conditional equation (6) is the focal length of the lens having the strongest negative refractive power among the lenses adjacent to the image side of the RN lens group GRN and the most positive lens among the lenses adjacent to the image side of the RN lens group GRN. It defines the ratio to the focal length of a lens with a strong refractive power. By satisfying this conditional expression (6), various aberrations such as coma can be effectively corrected.

When the corresponding value of the above conditional expression (6) exceeds the upper limit value, the refractive power of the lens having a positive refractive power on the image side of the focusing lens group becomes strong, and the occurrence of coma aberration becomes excessive. By setting the upper limit value of the conditional expression (6) to 1.90, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit value of the conditional expression (6) to 1.80.

When the corresponding value of the above conditional expression (6) is less than the lower limit value, the refractive power of the lens having a negative refractive power on the image side of the focusing lens group becomes strong, and the correction of coma aberration becomes excessive. By setting the lower limit value of the conditional expression (6) to 0.80, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit value of the conditional expression (6) to 0.90.

In the variable magnification optical system according to the present embodiment, it is preferable to satisfy the following conditional expression (7).

1.80 <f1 / fw <3.50 ... (7)
However,
fw: Focal length of the variable magnification optical system in the wide-angle end state f1: Focal length of the front lens group GFS

The conditional expression (7) defines the ratio between the focal length of the front lens group GFS and the focal length of the variable magnification optical system in the wide-angle end state. By satisfying this conditional equation (7), it is possible to prevent the lens barrel from becoming large in size and suppress fluctuations in various aberrations such as spherical aberration when scaling from the wide-angle end to the telephoto end.

When the corresponding value of the above conditional expression (7) exceeds the upper limit value, the refractive power of the front lens group GFS becomes weak and the lens barrel becomes large. By setting the upper limit value of the conditional expression (7) to 3.30, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of the present embodiment, it is preferable to set the upper limit value of the conditional expression (7) to 3.10.

When the corresponding value of the above conditional expression (7) is less than the lower limit value, the refractive power of the front lens group GFS becomes strong, and various aberrations such as spherical aberration at the time of scaling from the wide-angle end to the telephoto end are corrected. Becomes difficult. By setting the lower limit value of the conditional expression (7) to 1.90, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of the present embodiment, it is preferable to set the lower limit value of the conditional expression (7) to 2.00, and it is more preferable to set the lower limit value of the conditional expression (7) to 2.10. preferable.

In the variable magnification optical system according to the present embodiment, it is preferable to satisfy the following conditional expression (8).

3.70 <f1 / (-fTM1) <5.00 ... (8)
However,
fTM1: Focal length of M1 lens group GM1 in the telephoto end state f1: Focal length of front lens group GFS

Conditional expression (8) defines the ratio between the focal length of the front lens group GFS and the focal length of the M1 lens group GM1. By satisfying this conditional expression (8), it is possible to suppress fluctuations in various aberrations such as spherical aberration when scaling from the wide-angle end to the telephoto end.

When the corresponding value of the above conditional expression (8) exceeds the upper limit value, the refractive power of the M1 lens group GM1 becomes stronger, and fluctuations of various aberrations such as spherical aberration at the time of scaling from the wide-angle end to the telephoto end are caused. It becomes difficult to suppress. By setting the upper limit value of the conditional expression (8) to 4.90, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of the present embodiment, it is preferable to set the upper limit value of the conditional expression (8) to 4.80.

When the corresponding value of the above conditional expression (8) is less than the lower limit value, the refractive power of the front lens group GFS becomes strong, and various aberrations such as spherical aberration at the time of scaling from the wide-angle end to the telephoto end are corrected. Becomes difficult. By setting the lower limit value of the conditional expression (8) to 3.90, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of the present embodiment, it is preferable to set the lower limit value of the conditional expression (8) to 3.95.

In the variable magnification optical system according to the present embodiment, it is preferable to satisfy the following conditional expression (9).

3.20 <f1 / fTM2 <5.00 ... (9)
However,
f1: Focal length of front lens group GFS

Conditional expression (9) defines the ratio between the focal length of the front lens group GFS and the focal length of the M2 lens group GM2. By satisfying this conditional equation (9), it is possible to suppress fluctuations in various aberrations such as spherical aberration when scaling from the wide-angle end to the telephoto end.

When the corresponding value of the above conditional expression (9) exceeds the upper limit value, the refractive power of the M2 lens group GM2 becomes stronger, and fluctuations of various aberrations such as spherical aberration at the time of scaling from the wide-angle end to the telephoto end are caused. It becomes difficult to suppress. By setting the upper limit value of the conditional expression (9) to 4.80, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of the present embodiment, it is preferable to set the upper limit value of the conditional expression (9) to 4.60.

When the corresponding value of the above conditional expression (9) is less than the lower limit value, the refractive power of the front lens group GFS becomes strong, and various aberrations such as spherical aberration at the time of scaling from the wide-angle end to the telephoto end are corrected. Becomes difficult. By setting the lower limit value of the conditional expression (9) to 3.40, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of the present embodiment, it is preferable to set the lower limit value of the conditional expression (11) to 3.60.

The optical device and the imaging device of the present embodiment are configured to include the variable magnification optical system having the above-described configuration. As a specific example thereof, a camera provided with the above-mentioned variable magnification optical system ZL (corresponding to the imaging device of the present invention) will be described with reference to FIG. As shown in FIG. 26, the camera 1 has a lens assembly configuration in which the photographing lens 2 is interchangeable, and the photographing lens 2 is provided with a variable magnification optical system having the above-described configuration. That is, the photographing lens 2 corresponds to the optical device of the present invention. The camera 1 is a digital camera, and 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.

With the above configuration, the camera 1 equipped with the variable magnification optical system ZL on the photographing lens 2 is capable of high-speed AF and AF without increasing the size of the lens barrel by reducing the size and weight of the focusing lens group. Quietness can be achieved. Further, it is possible to satisfactorily suppress the aberration fluctuation at the time of scaling from the wide-angle end state to the telephoto end state and the aberration fluctuation at the time of focusing from an infinity object to a short-distance object, and to realize good optical performance.

Subsequently, the manufacturing method of the above-mentioned variable magnification optical system ZL will be outlined with reference to FIG. 27. First, in order from the object side, the front lens group GFS having a positive refractive power, the M1 lens group GM1 having a negative refractive power, the M2 lens group GM2 having a positive refractive power, and the RN having a negative refractive power. The lens group GRN is arranged (step ST1). Then, at the time of magnification change, the distance between the front lens group GFS and the M1 lens group GM1 changes, the distance between the M1 lens group GM1 and the M2 lens group GM2 changes, and the distance between the M2 lens group GM2 and the RN lens group GRN changes. It is configured as follows. (Step ST2). At this time, the RN lens group GRN is configured to move when focusing from an infinity object to a short-range object (step ST3), and the M2 lens group GM2 has an A lens group satisfying a predetermined conditional expression. The lens is arranged so as to (step ST4).

Hereinafter, the variable magnification optical system (zoom lens) ZL according to the embodiment of the present embodiment will be described with reference to the drawings. 1, FIG. 6, FIG. 11, FIG. 16, and FIG. 21 are cross sections showing the configuration and refractive power distribution of the variable magnification optical system ZL {ZL (1) to ZL (5)} according to the first to fifth embodiments. It is a figure. At the bottom of the cross-sectional view of the variable magnification optical systems ZL (1) to ZL (5), the movement along the optical axis of each lens group when scaling from the wide-angle end state (W) to the telephoto end state (T). The direction is indicated by an arrow. Further, the moving direction when the focusing group GRN focuses on a short-distance object from infinity is indicated by an arrow together with the characters "focusing".

In FIGS. 1, 6, 11, 16, and 21, each lens group is represented by a combination of reference numerals G and numbers or alphabets, and each lens is represented by a combination of reference numerals L and numbers. 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 5 are shown below, and Tables 1 to 5 are tables showing the specification data in each of the first to fifth embodiments. In each embodiment, the d-line (wavelength 587.562 nm) and the g-line (wavelength 435.835 nm) are selected as the calculation targets of the aberration characteristics.

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 object surface indicates an object surface, the radius of curvature "∞" indicates a plane or an aperture, (aperture S) indicates an aperture diaphragm S, and the image plane indicates an image plane I. The description of the refractive index nd of air = 1.00000 is omitted.

In the [Various data] table, f is the focal length of the entire lens system, FNO is the F number, 2ω is the angle of view (unit is ° (degree), and ω is the half angle of view), and Ymax is the maximum image height. 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 distance to the surface I (back focus) 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.

The table of [variable spacing data] shows the plane numbers (for example, plane numbers 5, 13, 25, 29 in the first embodiment) in which the plane spacing is "variable" in the table showing the [lens specifications]. Indicates the surface spacing. 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 focused states at infinity and short distance.

In the [Lens Group Data] table, the start surface (the surface closest to the object) and the focal length of each of the first to fifth lens groups (or the first to fourth lens groups or the first to sixth lens groups) are shown. Shown.

The table of [Conditional expression corresponding values] shows the values corresponding to the above conditional expressions (1) to (9).

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 and 1. FIG. 1 is a diagram showing a lens configuration of a variable magnification optical system according to a first embodiment of the present embodiment. In the variable magnification optical system ZL (1) according to the present embodiment, in order from the object side, the first lens group G1 having a positive refractive power, the second lens group G2 having a negative refractive power, and the positive refractive power It is composed of a third lens group G3 having a negative refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. 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.

In relation to the above embodiment, the first lens group G1 is in the front lens group GFS, the second lens group G2 is in the M1 lens group GM1, the third lens group G3 is in the M2 lens group GM2, and the fourth lens. Group G4 corresponds to the RN lens group GRN.

The first lens group G1 includes a positive convex flat lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a convex surface facing the object side, and a positive meniscus lens L13 having a convex surface facing the object side in order from the object side. Consists of a bonded positive lens.

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

The third lens group G3 is a junction positive lens of a negative meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32, and a biconvex positive lens L33 and a biconcave shape in order from the object side. From the bonded positive lens with the negative lens L34, the aperture aperture S, the bonded negative lens with the negative meniscus lens L35 with the convex surface facing the object side and the biconvex positive lens L36, and the biconvex positive lens L37. It is composed.

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

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 in order from the object side.

In the optical system according to the present embodiment, focusing of a long-distance object to a short-distance object is performed by moving the fourth lens group G4 in the image plane direction.

In the variable magnification optical system according to the present embodiment, camera shake is caused by moving the junction positive lens of the negative meniscus lens L31 with the convex surface facing the object side and the biconvex positive lens L32 in the direction orthogonal to the optical axis. The image formation position displacement due to the above is corrected. That is, these lenses L31 and L32 form a vibration-proof lens group, which corresponds to the A lens group of the present invention and the present embodiment.

To correct rotational blur at an angle θ with a lens whose focal length of the entire system is f and whose anti-vibration coefficient (ratio of image movement amount on the imaging surface to the movement amount of the moving lens group in blur correction) is K, The moving lens group for blur correction may be moved in the direction orthogonal to the optical axis by (f · tan θ) / K. At the wide-angle end of the first embodiment, the vibration isolation coefficient is 1.65 and the focal length is 72.1 mm. Therefore, the amount of movement of the vibration isolation lens group for correcting the rotational blur of 0.30 ° is 0.23 mm. In the telephoto end state of the first embodiment, the vibration isolation coefficient is 2.10 and the focal length is 292.0 mm. Therefore, the amount of movement of the vibration isolation lens group for correcting the rotational blur of 0.20 ° is 0.49 mm.

Table 1 below lists the specifications of the optical system according to this embodiment. In Table 1, f indicates the focal length and BF indicates the back focus.

(Table 1) First Example
[Lens specifications]
Surface number RD nd νd
Physical surface ∞
1 109.4870 4.600 1.48749 70.31
2 ∞ 0.200
3 101.1800 1.800 1.62004 36.40
4 49.8109 7.200 1.49700 81.61
5 385.8166 Variable
6 176.0187 1.700 1.69680 55.52
7 31.3680 5.150
8 32.6087 5.500 1.78472 25.64
9 -129.7634 1.447
10 -415.4105 1.300 1.77250 49.62
11 34.3083 4.300
12 -33.1502 1.200 1.85026 32.35
13 -203.5644 Variable
14 70.9040 1.200 1.80100 34.92
15 30.2785 5.900 1.64000 60.20
16 -70.1396 1.500
17 34.0885 6.000 1.48749 70.31
18 -42.6106 1.300 1.80610 40.97
19 401.2557 2.700
20 ∞ 14.110 (Aperture S)
21 350.0000 1.200 1.83400 37.18
22 30.1592 4.800 1.51680 63.88
23 -94.9908 0.200
24 66.3243 2.800 1.80100 34.92
25 -132.5118 Variable
26 -92.0997 2.200 1.80518 25.45
27 -44.0090 6.500
28 -36.9702 1.000 1.77250 49.62
29 68.3346 Variable
30 -24.5000 1.400 1.62004 36.40
31 -41.1519 0.200
32 106.0000 3.800 1.67003 47.14
33 -106.0000 BF
Image plane ∞

[Various data]
Variable ratio 4.05
WMT
f 72.1 100.0 292.0
FNO 4.49 4.86 5.88
2ω 33.96 24.48 8.44
Ymax 21.60 21.60 21.60
TL 190.13 205.07 245.82
BF 39.12 46.45 67.12

[Variable interval data]
WMTWMT
Infinity Infinity Infinity Infinity Short Distance Short Distance Short Distance
d5 6.204 21.150 61.895 6.204 21.150 61.895
d13 30.000 22.666 2.000 30.000 22.666 2.000
d25 2.180 3.742 3.895 2.837 4.562 5.614
d29 21.418 19.856 19.703 20.761 19.036 17.984

[Lens group data]
Group start surface f
G1 1 145.319
G2 6 -29.546
G3 14 38.298
G4 26 -48.034
G5 30 324.470

[Conditional expression correspondence value]
(1) fvr / fTM2 = 1.755
(2) nvrN / nvrP = 1.098
(3) νvrN / νvrP = 0.580
(4) (-fTM1) / f1 = 0.203
(5) fTM2 / f1 = 0.264
(6) (-fN) /fP = 1.266
(7) f1 / fw = 2.016
(8) f1 / (-fTM1) = 4.918
(9) f1 / fTM2 = 3.794

2 (a) and 2 (b) are aberration diagrams at infinity focusing in the wide-angle end state of the variable magnification optical system having the vibration isolation function according to the first embodiment, and rotation of 0.30 °, respectively. It is a meridional lateral aberration diagram when blur correction is performed for blur. FIG. 3 is a diagram of various aberrations at infinity focusing in the intermediate focal length state of the variable magnification optical system having the vibration isolation function according to the first embodiment. 4 (a) and 4 (b) are aberration diagrams at infinity focusing in the telephoto end state of the variable magnification optical system having the vibration isolation function according to the first embodiment, and 0.20 ° rotation, respectively. It is a meridional lateral aberration diagram when blur correction is performed for blur. 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 first embodiment, respectively. It is a diagram of various aberrations of.

In each aberration diagram of FIGS. 2 to 5, FNO indicates an F number, NA indicates a numerical aperture, and Y indicates an image height. The spherical aberration diagram shows the F number or numerical aperture value corresponding to the maximum aperture, the astigmatism diagram and the distortion diagram show the maximum image height, and the coma aberration diagram shows the value of each image height. .. d is the d line (λ = 587.6 nm) and g is the g line (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 diagram of each example shown below, the same reference numerals as those of this example are used.

From each aberration diagram, the variable magnification optical system according to this embodiment satisfactorily corrects various aberrations from the wide-angle end state to the telephoto end state and has excellent imaging performance, and even during short-distance focusing. It can be seen that it has excellent imaging performance.

(Second Example)
FIG. 6 is a diagram showing a lens configuration of a variable magnification optical system according to a second embodiment of the present embodiment. In the variable magnification optical system according to the present embodiment, in order from the object side, the first lens group G1 having a positive refractive power, the second lens group G2 having a negative refractive power, and the third lens group G2 having a negative refractive power. It is composed of a lens group G3, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power.

In relation to the above embodiment, the first lens group G1 is in the front lens group GFS, the second lens group G2 and the third lens group G3 are in the M1 lens group GM1, and the fourth lens group G4 is in the M2 lens group. The fifth lens group G5 corresponds to the GM2 and the RN lens group GRN.

The first lens group G1 includes a positive convex flat lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a convex surface facing the object side, and a positive meniscus lens L13 having a convex surface facing the object side in order from the object side. Consists of a bonded positive lens.

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

The third lens group G3 is composed of a negative meniscus lens L31 with a concave surface facing the object side.

The fourth lens group G4 has a negative meniscus lens L41 having a convex surface facing the object side and a biconvex positive lens L42 in order from the object side, and a biconvex positive lens L43 and a biconcave positive lens. From the junction positive lens with the negative lens L44, the aperture aperture S, the junction negative lens with the negative meniscus lens L45 with the convex surface facing the object side and the biconvex positive lens L46, and the biconvex positive lens L47. It is composed.

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

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

In the optical system according to the present embodiment, focusing of a long-distance object to a short-distance object is performed by moving the fifth lens group G5 in the image plane direction. Further, by moving the junction positive lens of the negative meniscus lens L41 with the convex surface facing the object side and the biconvex positive lens L42 in the direction orthogonal to the optical axis, the displacement of the imaging position due to camera shake or the like is corrected. .. That is, these lenses L41 and L42 form a vibration-proof lens group, which corresponds to the A lens group of the present invention and the present embodiment.

To correct rotational blurring at an angle θ with a lens whose focal length of the entire system is f and whose anti-vibration coefficient (ratio of image movement amount on the imaging surface to the movement amount of the moving lens group in blur correction) is K. Is sufficient to move the moving lens group for blur correction by (f · tan θ) / K in the direction orthogonal to the optical axis. At the wide-angle end of the second embodiment, the vibration isolation coefficient is 1.66 and the focal length is 72.1 mm. Therefore, the amount of movement of the vibration isolation lens group for correcting the rotational blur of 0.30 ° is 0.23 mm. In the telephoto end state of the second embodiment, the vibration isolation coefficient is 2.10 and the focal length is 292.0 mm. Therefore, the amount of movement of the vibration isolation lens group for correcting the rotational blur of 0.20 ° is 0.49 mm.

Table 2 below lists the specifications of the optical system according to this embodiment.

(Table 2) Second Example
[Lens specifications]
Surface number RD nd νd
Physical surface ∞
1 107.5723 4.600 1.48749 70.32
2 ∞ 0.200
3 96.9007 1.800 1.62004 36.40
4 47.8324 7.200 1.49700 81.61
5 361.3792 Variable
6 139.8663 1.700 1.69680 55.52
7 33.7621 6.806
8 33.5312 5.500 1.78472 25.64
9 -139.8348 0.637
10 -492.0620 1.300 1.80400 46.60
11 35.1115 Variable
12 -34.6163 1.200 1.83400 37.18
13 -377.1306 Variable
14 74.8969 1.200 1.80100 34.92
15 31.6202 5.900 1.64000 60.19
16 -69.0444 1.500
17 34.2668 6.000 1.48749 70.32
18 -42.8334 1.300 1.80610 40.97
19 434.9585 2.700
20 ∞ 14.312 (Aperture S)
21 350.0000 1.200 1.83400 37.18
22 30.4007 4.800 1.51680 63.88
23 -98.0361 0.200
24 68.9306 2.800 1.80100 34.92
25 -129.3404 Variable
26 -90.5065 2.200 1.80518 25.45
27 -44.1796 6.500
28 -37.6907 1.000 1.77250 49.62
29 68.3000 Variable
30 -24.5545 1.400 1.62004 36.40
31 -41.7070 0.200
32 106.0000 3.800 1.67003 47.14
33 -106.0000 BF
Image plane ∞

[Various data]
Variable ratio 4.05
WMT
f 72.1 100.0 292.0
FNO 4.53 4.89 5.88
2ω 33.98 24.48 8.44
Ymax 21.60 21.60 21.60
TL 190.82 206.02 245.82
BF 39.12 46.27 66.46

[Variable interval data]
WMTWMT
Infinity Infinity Infinity Infinity Short Distance Short Distance Short Distance
d5 2.861 18.057 57.861 2.861 18.057 57.861
d11 5.727 5.812 6.883 5.727 5.812 6.883
d13 30.500 23.259 2.000 30.500 23.259 2.000
d25 2.246 3.634 3.634 2.888 4.436 5.329
d29 22.411 21.023 21.023 21.770 20.221 19.329

[Lens group data]
Group start surface f
G1 1 141.867
G2 6 -104.910
G3 12 -45.774
G4 14 38.681
G5 26 -48.266
G6 30 340.779

[Conditional expression correspondence value]
(1) fvr / fTM2 = 1.764
(2) nvrN / nvrP = 1.098
(3) νvrN / νvrP = 0.580
(4) (-fTM1) / f1 = 0.208
(5) fTM2 / f1 = 0.273
(6) (-fN) / fP = 1.248
(7) f1 / fw = 1.968
(8) f1 / (-fTM1) = 4.804
(9) f1 / fTM2 = 3.668

7 (a) and 7 (b) are aberration diagrams at infinity focusing in the wide-angle end state of the variable magnification optical system having the vibration isolation function according to the second embodiment, and rotation of 0.30 °, respectively. It is a meridional lateral aberration diagram when blur correction is performed for blur. FIG. 8 is a diagram of various aberrations at infinity focusing in the intermediate focal length state of the variable magnification optical system having the vibration isolation function according to the second embodiment. 9 (a) and 9 (b) are aberration diagrams at infinity focusing in the telephoto end state of the variable magnification optical system having the vibration isolation function according to the second embodiment, and 0.20 ° rotation, respectively. It is a meridional lateral aberration diagram when blur correction is performed for blur. 10 (a), 10 (b), and 10 (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 this embodiment satisfactorily corrects various aberrations from the wide-angle end state to the telephoto end state and has excellent imaging performance, and even during short-distance focusing. It can be seen that it has excellent imaging performance.

(Third Example)
FIG. 11 is a diagram showing a lens configuration of a variable magnification optical system according to a third embodiment of the present embodiment. In the variable magnification optical system according to the present embodiment, the first lens group G1 having a positive refractive power, the second lens group G2 having a negative refractive power, and the third lens group G2 having a positive refractive power are arranged in this order from the object side. It is composed of a lens group G3, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power.

In relation to the above embodiment, the first lens group G1 is in the front lens group GFS, the second lens group G2 is in the M1 lens group GM1, and the third lens group G3 and the fourth lens group G4 are in the M2 lens group. The fifth lens group G5 corresponds to the GM2 and the RN lens group GRN.

The first lens group G1 includes a positive convex flat lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a convex surface facing the object side, and a positive meniscus lens L13 having a convex surface facing the object side in order from the object side. Consists of a bonded positive lens.

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

The third lens group G3 is a junction positive lens of a negative meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32, and a biconvex positive lens L33 and a biconcave shape in order from the object side. It is composed of a positive lens joined with a negative lens L34 and an aperture stop S.

The fourth lens group G4 is composed of a negative meniscus lens L41 having a convex surface facing the object side, a junction negative lens of a biconvex positive lens L42, and a biconvex positive lens L43 in order from the object side. ..

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

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

In the optical system according to the present embodiment, focusing of a long-distance object to a short-distance object is performed by moving the fifth lens group G5 in the image plane direction. Further, by moving the junction positive lens of the negative meniscus lens L31 with the convex surface facing the object side and the biconvex positive lens L32 in the direction orthogonal to the optical axis, the displacement of the imaging position due to camera shake or the like is corrected. .. That is, these lenses L31 and L32 form a vibration-proof lens group, which corresponds to the A lens group of the present invention and the present embodiment.

To correct rotational blurring at an angle θ with a lens whose focal length of the entire system is f and whose anti-vibration coefficient (ratio of image movement amount on the imaging surface to the movement amount of the moving lens group in blur correction) is K. Is sufficient to move the moving lens group for blur correction by (f · tan θ) / K in the direction orthogonal to the optical axis. At the wide-angle end of the third embodiment, the vibration isolation coefficient is 1.65 and the focal length is 72.1 mm. Therefore, the amount of movement of the vibration isolation lens group for correcting the rotational blur of 0.30 ° is 0.23 mm. In the telephoto end state of the third embodiment, the vibration isolation coefficient is 2.10 and the focal length is 292.0 mm. Therefore, the amount of movement of the vibration isolation lens group for correcting the rotational blur of 0.20 ° is 0.49 mm.

Table 3 below lists the specifications of the optical system according to this embodiment.

(Table 3) Third Example
[Lens specifications]
Surface number RD nd νd
Physical surface ∞
1 106.7563 4.600 1.48749 70.32
2 ∞ 0.200
3 99.4635 1.800 1.62004 36.40
4 49.2336 7.200 1.49700 81.61
5 332.7367 Variable
6 152.3830 1.700 1.69680 55.52
7 31.0229 5.695
8 32.0867 5.500 1.78472 25.64
9 -139.5695 1.399
10 -403.4713 1.300 1.77250 49.62
11 33.8214 4.300
12 -34.0003 1.200 1.85026 32.35
13 -235.0206 Variable
14 69.3622 1.200 1.80100 34.92
15 29.8420 5.900 1.64000 60.19
16 -71.2277 1.500
17 34.4997 6.000 1.48749 70.32
18 -43.1246 1.300 1.80610 40.97
19 382.2412 2.700
20 ∞ Variable (Aperture S)
21 350.0000 1.200 1.83400 37.18
22 30.6178 4.800 1.51680 63.88
23 -88.2508 0.200
24 66.4312 2.800 1.80100 34.92
25 -142.7832 Variable
26 -93.6206 2.200 1.80518 25.45
27 -44.3477 6.500
28 -37.1859 1.000 1.77250 49.62
29 68.3000 Variable
30 -24.9508 1.400 1.62004 36.40
31 -42.7086 0.200
32 106.0000 3.800 1.67003 47.14
33 -106.0000 BF
Image plane ∞

[Various data]
Variable ratio 4.05
WMT
f 72.1 100.0 292.0
FNO 4.49 4.85 5.88
2ω 33.98 24.48 8.44
Ymax 21.60 21.60 21.60
TL 190.26 205.79 245.82
BF 39.12 46.10 67.12

[Variable interval data]
WMTWMT
Infinity Infinity Infinity Infinity Short Distance Short Distance Short Distance
d5 5.981 21.510 61.535 5.981 21.510 61.535
d13 30.000 23.014 2.000 30.000 23.014 2.000
d20 14.365 14.107 14.196 14.365 14.107 14.196
d25 2.202 3.476 3.676 2.867 4.301 5.396
d29 21.004 19.988 19.700 20.339 19.163 17.979

[Lens group data]
Group start surface f
G1 1 145.335
G2 6 -29.607
G3 14 48.974
G4 21 62.364
G5 26 -48.296
G6 30 336.791

[Conditional expression correspondence value]
(1) fvr / fTM2 = 1.747
(2) nvrN / nvrP = 1.098
(3) νvrN / νvrP = 0.580
(4) (-fTM1) / f1 = 0.204
(5) fTM2 / f1 = 0.264
(6) (-fN) /fP = 1.253
(7) f1 / fw = 2.016
(8) f1 / (-fTM1) = 4.909
(9) f1 / fTM2 = 3.786

12 (a) and 12 (b) are aberration diagrams at infinity focusing in the wide-angle end state of the variable magnification optical system having the vibration isolation function according to the third embodiment, and rotation of 0.30 °, respectively. It is a meridional lateral aberration diagram when blur correction is performed for blur. FIG. 13 is a diagram of various aberrations at infinity focusing in the intermediate focal length state of the variable magnification optical system having the vibration isolation function according to the third embodiment. 14 (a) and 14 (b) are aberration diagrams at infinity focusing in the telephoto end state of the variable magnification optical system having the vibration isolation function according to the third embodiment, and 0.20 ° rotation, respectively. It is a meridional lateral aberration diagram when blur correction is performed for blur. 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 third embodiment, respectively. It is a diagram of various aberrations of.

From each aberration diagram, the variable magnification optical system according to this embodiment satisfactorily corrects various aberrations from the wide-angle end state to the telephoto end state and has excellent imaging performance, and even during short-distance focusing. It can be seen that it has excellent imaging performance.

(Fourth Example)
FIG. 16 is a diagram showing a lens configuration of a variable magnification optical system according to a fourth embodiment of the present embodiment. In the variable magnification optical system according to the present embodiment, the first lens group G1 having a positive refractive power, the second lens group G2 having a negative refractive power, and the third lens group G2 having a positive refractive power are arranged in this order from the object side. It is composed of a lens group G3 and a fourth lens group G4 having a negative refractive power.

In relation to the above embodiment, the first lens group G1 is in the front lens group GFS, the second lens group G2 is in the M1 lens group GM1, the third lens group G3 is in the M2 lens group GM2, and the fourth lens. Group G4 corresponds to the RN lens group GRN.

The first lens group G1 is a junction positive lens of a positive convex flat lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a convex surface facing the object side, and a biconvex positive lens L13 in order from the object side. It consists of.

The second lens group G2 has a negative meniscus lens L21 with a convex surface facing the object side, a biconvex positive lens L22, a biconcave negative lens L23, and a concave surface facing the object side in order from the object side. It consists of a negative meniscus lens L24.

In the third lens group G3, in order from the object side, a negative meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32 are joined, and a biconvex positive lens L33 and a concave surface on the object side. A positive lens with a negative meniscus lens L34 facing the lens, an aperture aperture S, a negative lens with a negative meniscus lens L35 with a convex surface facing the object side, and a biconvex positive lens L36, and a biconvex positive lens. It consists of a lens L37.

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

In the optical system according to the present embodiment, focusing of a long-distance object to a short-distance object is performed by moving the fourth lens group G4 in the image plane direction.

In the variable magnification optical system according to the present embodiment, camera shake is caused by moving the junction positive lens of the negative meniscus lens L31 with the convex surface facing the object side and the biconvex positive lens L32 in the direction orthogonal to the optical axis. The image formation position displacement due to the above is corrected. That is, these lenses 31 and L32 form a vibration-proof lens group, which corresponds to the A lens group of the present invention and the present embodiment.

To correct rotational blurring at an angle θ with a lens whose focal length of the entire system is f and whose anti-vibration coefficient (ratio of image movement amount on the imaging surface to the movement amount of the moving lens group in blur correction) is K. Is sufficient to move the moving lens group for blur correction by (f · tan θ) / K in the direction orthogonal to the optical axis. At the wide-angle end of the fourth embodiment, the vibration isolation coefficient is 1.64 and the focal length is 72.1 mm. Therefore, the amount of movement of the vibration isolation lens group for correcting the rotational blur of 0.30 ° is 0.23 mm. In the telephoto end state of the fourth embodiment, the vibration isolation coefficient is 2.10 and the focal length is 292.0 mm. Therefore, the amount of movement of the vibration isolation lens group for correcting the rotational blur of 0.20 ° is 0.48 mm.

Table 4 below lists the specifications of the optical system according to this embodiment.

(Table 4) Fourth Example
[Lens specifications]
Surface number RD nd νd
Physical surface ∞
1 124.8083 4.600 1.48749 70.32
2 ∞ 0.200
3 111.5077 1.800 1.62004 36.40
4 51.2894 7.200 1.49700 81.61
5 -4057.4569 Variable
6 1232.8716 1.700 1.69680 55.52
7 32.6209 3.624
8 33.1180 5.224 1.78472 25.64
9 -126.9611 1.768
10 -243.6400 1.300 1.77250 49.62
11 37.7537 4.300
12 -33.1285 1.200 1.85026 32.35
13 -124.4232 variable
14 80.2408 1.200 1.80100 34.92
15 32.8582 5.862 1.64000 60.19
16 -70.9140 1.500
17 40.5722 6.000 1.48749 70.32
18 -43.0594 1.300 1.80610 40.97
19 -2388.6437 2.700
20 ∞ 18.922 (Aperture S)
21 812.4602 1.200 1.83400 37.18
22 34.5376 5.275 1.51680 63.88
23 -59.1982 0.200
24 75.5608 3.209 1.80100 34.92
25 -197.1038 Variable
26 -76.9453 2.263 1.80518 25.45
27 -41.7537 6.500
28 -33.9973 1.000 1.77250 49.62
29 132.3165 BF
Image plane ∞

[Various data]
Variable ratio 4.05
WMT
f 72.1 100.0 292.0
FNO 4.68 4.90 6.19
2ω 33.78 23.92 8.22
Ymax 21.60 21.60 21.60
TL 189.82 210.78 245.82
BF 64.99 69.56 89.99

WMTWMT
Infinity Infinity Infinity Infinity Short Distance Short Distance Short Distance
d5 2.000 22.956 58.000 2.000 22.956 58.000
d13 30.000 25.721 2.000 30.000 25.721 2.000
d25 2.777 2.495 5.785 3.449 3.343 7.497

[Lens group data]
Group start surface f
G1 1 139.523
G2 6 -29.733
G3 14 41.597
G4 26 -54.885

[Conditional expression correspondence value]
(1) fvr / fTM2 = 1.728
(2) nvrN / nvrP = 1.098
(3) νvrN / νvrP = 0.580
(4) (-fTM1) / f1 = 0.213
(5) fTM2 / f1 = 0.298
(7) f1 / fw = 1.935
(8) f1 / (-fTM1) = 4.693
(9) f1 / fTM2 = 3.354

17 (a) and 17 (b) are aberration diagrams at the time of focusing at infinity at the wide-angle end state of the variable magnification optical system having the vibration isolation function according to the fourth embodiment, and 0.30 ° rotational blur, respectively. It is a meridional lateral aberration diagram when the blur correction is performed on. FIG. 18 is a diagram of various aberrations at infinity focusing in the intermediate focal length state of the variable magnification optical system having the vibration isolation function according to the fourth embodiment. 19 (a) and 19 (b) are aberration diagrams at infinity focusing in the telephoto end state of the variable magnification optical system having the vibration isolation function according to the fourth embodiment, and 0.20 ° rotational blur, respectively. It is a meridional lateral aberration diagram when the blur correction is performed on. 20 (a), 20 (b) and 20 (c)
Are aberration diagrams at the time of short-range 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 fourth embodiment, respectively.

From each aberration diagram, the variable magnification optical system according to this embodiment satisfactorily corrects various aberrations from the wide-angle end state to the telephoto end state and has excellent imaging performance, and even during short-distance focusing. It can be seen that it has excellent imaging performance.

(Fifth Example)
FIG. 21 is a diagram showing a lens configuration of a variable magnification optical system according to a fifth embodiment of the present embodiment. In the variable magnification optical system according to the present embodiment, 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, and a third lens group having a positive refractive power. It is composed of a lens group G3, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power.

In relation to the above embodiment, the first lens group G1 is in the front lens group GFS, the second lens group G2 is in the M1 lens group GM1, the third lens group G3 is in the M2 lens group GM2, and the fourth lens. Group G4 corresponds to the RN lens group GRN.

The first lens group G1 includes a positive convex flat lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a convex surface facing the object side, and a positive meniscus lens L13 having a convex surface facing the object side in order from the object side. Consists of a bonded positive lens.

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

The third lens group G3 is a junction positive lens of a negative meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32, and a biconvex positive lens L33 and a biconcave shape in order from the object side. From the bonded positive lens with the negative lens L34, the aperture aperture S, the bonded negative lens with the negative meniscus lens L35 with the convex surface facing the object side and the biconvex positive lens L36, and the biconvex positive lens L37. It is composed.

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

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 convex surface facing the object side in order from the object side. ..

In the optical system according to the present embodiment, focusing of a long-distance object to a short-distance object is performed by moving the fourth lens group G4 in the image plane direction. Further, by moving the junction positive lens of the negative meniscus lens L31 with the convex surface facing the object side and the biconvex positive lens L32 in the direction orthogonal to the optical axis, the displacement of the imaging position due to camera shake or the like is corrected. .. That is, these lenses 31 and L32 form a vibration-proof lens group, which corresponds to the A lens group of the present invention and the present embodiment.

To correct rotational blurring at an angle θ with a lens whose focal length of the entire system is f and whose anti-vibration coefficient (ratio of image movement amount on the imaging surface to the movement amount of the moving lens group in blur correction) is K. Is sufficient to move the moving lens group for blur correction by (f · tan θ) / K in the direction orthogonal to the optical axis. At the wide-angle end of the fourth embodiment, the vibration isolation coefficient is 1.65 and the focal length is 72.1 mm, so that the amount of movement of the vibration isolation lens group for correcting the rotational blur of 0.30 ° is 0.23 mm. In the telephoto end state of the fourth embodiment, the vibration isolation coefficient is 2.10 and the focal length is 292.0 mm. Therefore, the amount of movement of the vibration isolation lens group for correcting the rotational blur of 0.20 ° is 0.49 mm.

Table 5 below lists the specifications of the optical system according to this embodiment.

(Table 5) Fifth Example
[Lens specifications]
Surface number RD nd νd
Physical surface ∞
1 109.5099 4.600 1.48749 70.32
2 ∞ 0.200
3 101.8486 1.800 1.62004 36.40
4 49.8873 7.200 1.49700 81.61
5 403.0130 Variable
6 166.1577 1.700 1.69680 55.52
7 31.1882 3.953
8 32.0256 5.500 1.78472 25.64
9 -139.5816 1.553
10 -767.2482 1.300 1.77250 49.62
11 33.9202 4.300
12 -32.8351 1.200 1.85026 32.35
13 -256.2484 Variable
14 69.5902 1.200 1.80100 34.92
15 29.9877 5.900 1.64000 60.19
16 -70.0411 1.500
17 36.2271 6.000 1.48749 70.32
18 -39.9358 1.300 1.80610 40.97
19 820.8027 2.700
20 ∞ 14.092 (Aperture S)
21 427.1813 1.200 1.83400 37.18
22 31.7606 4.800 1.51680 63.88
23 -89.4727 0.200
24 73.5865 2.800 1.80100 34.92
25 -110.0493 Variable
26 -83.7398 2.200 1.80518 25.45
27 -42.9999 6.500
28 -36.8594 1.000 1.77250 49.62
29 73.0622 Variable
30 -26.0662 1.400 1.62004 36.4
31 -40.4068 0.200
32 143.0444 3.035 1.67003 47.14
33 -220.8402 0.200
34 100.4330 2.145 1.79002 47.32
35 170.3325 BF
Image plane ∞

[Various data]
Variable ratio 4.05
WMT
f 72.1 100.0 292.0
FNO 4.48 4.85 5.87
2ω 33.94 24.44 8.42
Ymax 21.60 21.60 21.60
TL 190.21 205.27 245.82
BF 39.12 46.37 67.13

[Variable interval data]
WMTWMT
Infinity Infinity Infinity Infinity Short Distance Short Distance Short Distance
d5 5.892 20.953 61.502 5.892 20.953 61.502
d13 30.000 22.752 2.000 30.000 22.752 2.000
d25 2.212 3.707 3.900 2.864 4.521 5.606
d29 21.306 19.811 19.618 20.654 18.997 17.912

[Lens group data]
Group start surface f
G1 1 145.022
G2 6 -29.562
G3 14 38.233
G4 26 -48.257
G5 30 318.066

[Conditional expression correspondence value]
(1) fvr / fTM2 = 1.738
(2) nvrN / nvrP = 1.098
(3) νvrN / νvrP = 0.580
(4) (-fTM1) / f1 = 0.204
(5) fTM2 / f1 = 0.264
(6) (-fN) / fP = 0.947
(7) f1 / fw = 2.011
(8) f1 / (-fTM1) = 4.906
(9) f1 / fTM2 = 3.793

22 (a) and 22 (b) are aberration diagrams at infinity focusing in the wide-angle end state of the variable magnification optical system having the vibration isolation function according to the fifth embodiment, and rotation of 0.30 °, respectively. It is a meridional lateral aberration diagram when blur correction is performed for blur. FIG. 23 is a diagram of various aberrations at infinity focusing in the intermediate focal length state of the variable magnification optical system having the vibration isolation function according to the fifth embodiment. 24 (a) and 24 (b) are aberration diagrams at infinity focusing in the telephoto end state of the variable magnification optical system having the vibration isolation function according to the fifth embodiment, and 0.20 ° rotation, respectively. It is a meridional lateral aberration diagram when blur correction is performed for blur. 25 (a), 25 (b), and 25 (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. It is a diagram of various aberrations of.

From each aberration diagram, the variable magnification optical system according to this embodiment satisfactorily corrects various aberrations from the wide-angle end state to the telephoto end state and has excellent imaging performance, and even during short-distance focusing. It can be seen that it has excellent imaging performance.

According to each of the above embodiments, by reducing the size and weight of the focusing lens group, high-speed AF and quietness during AF are realized without increasing the size of the lens barrel, and further, from the wide-angle end state to the telephoto end. It is possible to realize a variable magnification optical system that satisfactorily suppresses aberration fluctuations during scaling to a state and aberration fluctuations during focusing from an infinity object to a short-range object.

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

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

Numerical examples of the variable magnification optical system of the present application show a five-group configuration and a six-group configuration, but the present application is not limited to this, and the variable magnification optical system of other group configurations (for example, 7 groups, etc.) is shown. Can also be configured. 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 of the present application. 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.

Further, the lens surface of the lens constituting the variable magnification optical system of the present application may be a spherical surface or a flat surface, or may be an aspherical surface. When the lens surface is spherical or flat, lens processing and assembly adjustment can be facilitated, and deterioration of optical performance due to errors in lens processing and assembly adjustment 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, it can be either an aspherical surface obtained by grinding, a glass molded aspherical surface formed by molding glass into an aspherical shape, or a composite aspherical surface formed by forming a resin provided on the glass surface into an aspherical shape. Good. 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.

Further, an antireflection film having a high transmittance in a wide wavelength range may be applied to the lens surface of the lens constituting the variable magnification optical system of the present application. As a result, flare and ghost can be reduced, and high optical performance with high contrast can be achieved.

With the above configuration, the present camera 1 equipped with the variable magnification optical system according to the first embodiment as the photographing lens 2 is capable of high speed without increasing the size of the lens barrel by reducing the size and weight of the focusing lens group. Achieves excellent AF and quietness during AF, and also suppresses aberration fluctuations during scaling from the wide-angle end state to the telephoto end state and aberration fluctuations during focusing from an infinity object to a short-range object. , Good optical performance can be realized. Even if a camera equipped with the variable magnification optical system according to the second to seventh embodiments as the photographing lens 2, the same effect as that of the camera 1 can be obtained.

G1 1st lens group G2 2nd lens group G3 3rd lens group G4 4th lens group G5 5th lens group GFS front lens group GM1 M1 lens group GM2 M2 lens group GRN RN lens group I image plane S aperture aperture

Claims (25)

From the object side, the first lens group having a positive refractive power, the second lens group having a negative refractive power, the third lens group having a positive refractive power, and the fourth lens having a negative refractive power. It consists of substantially five lens groups, a group and a fifth lens group having a positive power.
At the time of scaling, the distance between each lens group changes,
When focusing from an infinite object to a short-distance object, the fourth lens group moves,
The third lens group is a variable magnification optical system having an A lens group that satisfies the following conditional expression.
1.10 <fvr / fTM2 <2.00
However, fvr: focal length of the A lens group fTM2; focal length of the third lens group in the telephoto end state. The variable magnification optical system according to claim 1, which satisfies the following conditional expression.
0.15 <(-fTM1) / f1 <0.35
However, fTM1; the focal length of the second lens group in the telephoto end state f1: the focal length of the first lens group. The variable magnification optical system according to claim 1 or 2, which satisfies the following conditional expression.
3.20 <f1 / fTM2 <5.00
However, f1: the focal length of the first lens group The variable magnification optical system according to any one of claims 1 to 3, which satisfies the following conditional expression.
0.20 <fTM2 / f1 <0.40
However, f1: the focal length of the first lens group The variable magnification optical system according to any one of claims 1 to 4, which satisfies the following conditional expression.
1.80 <f1 / fw <3.50
However, f1: the focal length of the first lens group 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 5, wherein the first lens group moves toward an object when the magnification is changed from the wide-angle end state to the telephoto end state. The variable magnification optical system according to any one of claims 1 to 6, wherein the first lens group is composed of three lenses. The variable magnification optical system according to any one of claims 1 to 7, wherein the lens arranged on the most object side of the second lens group is a lens having a negative refractive power. The variable magnification optical system according to any one of claims 1 to 8, wherein the lens arranged most on the image side is a lens having a positive refractive power. The variable magnification optics according to any one of claims 1 to 9, wherein the A-th lens group includes a lens having a negative refractive power and a lens having a positive refractive power in order from the object side, and satisfies the following conditional expression. system.
1.00 <nvrN / nvrP <1.25
However, nvrN: the refractive index of the lens having a negative refractive power in the A lens group nvrP: the refractive index of the lens having a positive refractive power in the A lens group. The variable magnification optics according to any one of claims 1 to 10, wherein the A-th lens group comprises a lens having a negative refractive power and a lens having a positive refractive power in order from the object side, and satisfies the following conditional expression. system.
0.30 <νvrN / νvrP <0.90
However, νvrN: Abbe number of lenses having a negative refractive power in the A lens group νvrP: Abbe number of lenses having a positive refractive power in the A lens group. From the object side, the front lens group composed of one lens group and having a positive refractive power, the M1 lens group composed of one or two lens groups and having a negative refractive power, and one or two lenses. It has an M2 lens group composed of groups and having a positive refractive power, and an RN lens group composed of one lens group and having a negative refractive power.
At the time of scaling, the distance between each lens group changes,
When focusing from an infinite object to a short-distance object, the RN lens group moves,
The M2 lens group is a variable magnification optical system having an A lens group that satisfies the following conditional expression.
1.10 <fvr / fTM2 <2.00
However, fvr: focal length of the A lens group fTM2: focal length of the M2 lens group in the telephoto end state. The variable magnification optical system according to claim 12, which satisfies the following conditional expression.
0.15 <(-fTM1) / f1 <0.35
However, fTM1; the focal length of the M1 lens group in the telephoto end state f1: the focal length of the front lens group. The variable magnification optical system according to claim 12 or 13, which satisfies the following conditional expression.
3.70 <f1 / (-fTM1) <5.00
However, fTM1; the focal length of the M1 lens group in the telephoto end state f1: the focal length of the front lens group. The variable magnification optical system according to any one of claims 12 to 14, which satisfies the following conditional expression.
3.20 <f1 / fTM2 <5.00
However, f1: the focal length of the front lens group The variable magnification optical system according to any one of claims 12 to 15, which satisfies the following conditional expression.
0.20 <fTM2 / f1 <0.40
However, f1: the focal length of the front lens group The variable magnification optical system according to any one of claims 12 to 16, which satisfies the following conditional expression.
1.80 <f1 / fw <3.50
However, f1: the focal length of the front lens group 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 12 to 17, wherein the front lens group moves to the object side when the magnification is changed from the wide-angle end state to the telephoto end state. The variable magnification optics according to any one of claims 12 to 18, wherein the A-th lens group comprises a lens having a negative refractive power and a lens having a positive refractive power in order from the object side, and satisfies the following conditional expression. system.
1.00 <nvrN / nvrP <1.25
However, nvrN: the refractive index of the lens having a negative refractive power in the A lens group nvrP: the refractive index of the lens having a positive refractive power in the A lens group. The variable magnification optics according to any one of claims 12 to 19, wherein the A-th lens group includes a lens having a negative refractive power and a lens having a positive refractive power in order from the object side, and satisfies the following conditional expression. system.
0.30 <νvrN / νvrP <0.90
However, νvrN: Abbe number of lenses having a negative refractive power in the A lens group νvrP: Abbe number of lenses having a positive refractive power in the A lens group. The variable magnification optical system according to any one of claims 12 to 20, wherein the lens group closest to the object side in the M1 lens group is fixed to the image plane at the time of scaling. The variable magnification optical system according to any one of claims 12 to 21, which has a lens having a negative refractive power and a lens having a positive refractive power in order from the object side adjacent to the image side of the RN lens group. The variable magnification optical system according to any one of claims 12 to 22, which satisfies the following conditional expression.
0.70 <(-fN) /fP <2.00
However, fN: the focal length of the lens having the strongest negative refractive power on the image side of the RN lens group fP: the focal length of the lens having the strongest positive refractive power on the image side of the RN lens group. An optical device having the variable magnification optical system according to any one of claims 1 to 23. An imaging device including the variable magnification optical system according to any one of claims 1 to 23 and an imaging unit that forms an image formed by the variable magnification optical system.

Images