JP2016080824A - Zoom imaging optical system with anti-shake capability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom imaging optical system with anti-shake capability, which offers a half view angle of approximately 2 degrees at the telephoto end, large image circle, and long focal length at the telephoto end, and which has a reduced total length and an anti-shake group with reduced weight.SOLUTION: A zoom imaging optical system with anti-shake capability comprises, in order from the object side, a first lens group G1 having positive refractive power, second lens group G2 having negative refractive power, and a rear lens group Gr having positive refractive power as a whole over an entire zoom range, where each lens group is separated from the one next thereto by an air gap that changes while zooming. The rear lens group Gr comprises at least two lens groups which independently move along respective tracks while zooming, and the second lens group G2 comprises a 2a group G2a having negative refractive power and a 2b group G2b having negative refractive power, where the 2b group G2b is moved in a direction perpendicular to an optical axis for anti-shake correction, and the 2a group G2a has a lens component having positive refractive power on the most object side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a variable magnification imaging optical system used for a still camera, a video camera, and the like, and more particularly to a variable magnification imaging optical system having a narrow angle of view and further having an image stabilization function.

In recent years, anti-vibration functions have been installed in imaging optical systems used in digital still cameras, etc., and failures due to camera shake have decreased even in photography using super telephoto lenses, making super telephoto lenses familiar. It is coming. For this reason, an imaging optical system having a longer focal length and a narrow angle of view has been demanded.

For example, an imaging optical system in which the angle of view at the telephoto end has a half angle of view of about 2 degrees to 2.5 degrees corresponding to a focal length of 500 mm to 600 mm in terms of 35 mm is also described in the patent literature.

JP 2011-17912 A JP 2012-208434 A JP 2011-186095 A JP 2013-97322 A JP 2014-125851 A

In a long focus imaging optical system with a narrow angle of view, it is first required to shorten the entire length of the optical system compared to the focal length. A value obtained by dividing the total length of the optical system by the focal length is called a telephoto ratio, and it is desirable that this value is sufficiently less than 1. If the total length is increased in proportion to the focal length, carrying and the like will be hindered. Therefore, in an optical system with a half angle of view of about 2 to 2.5 degrees, it is desired that the telephoto ratio is less than 0.7.

In order to reduce the telephoto ratio, a so-called telephoto type or telephoto type in which a lens unit having a positive refractive power is arranged closest to the object side and a lens unit having a negative refractive power arranged closer to the image side than the lens group having a positive refractive power is arranged. Although it is effective to use a refracting power arrangement called a lens, if a lens unit having a positive refracting power and a negative refracting power are arranged across the aperture from the object side, the chromatic aberration of magnification is corrected as the telephoto ratio is reduced. Has the weakness of becoming difficult.

In a long focus imaging optical system, the lens element has a large diameter as a whole, especially on the object side, and the weight of the image stabilizing lens group tends to increase. Since the weight of the anti-vibration lens group is increased, it is necessary to increase the size of the actuator in order to increase the driving force of the actuator, which further increases the size of the lens barrel. On the contrary, if the driving force of the actuator is insufficient, a problem arises in the responsiveness, and the correction accuracy of the camera shake is lowered, which causes a problem in the practicality of the entire product.

Further, in the long-focus imaging optical system, image blur due to camera shake increases, and the displacement of the image stabilizing group in the direction perpendicular to the optical axis tends to increase. When the displacement of the vibration isolation group in the direction perpendicular to the optical axis increases, the radial size of the vibration isolation operation unit and the actuator increases, and the diameter of the entire lens barrel increases.

Therefore, it is necessary to set the vibration-proof group as light as possible by suppressing the beam diameter, and the ratio of the displacement of the image in the direction perpendicular to the optical axis to the displacement in the direction perpendicular to the optical axis, that is, the vibration-proof coefficient. Must be sufficiently large to reduce the required displacement of the vibration isolation group.

Like the anti-vibration group, the focus group tends to have a large weight and displacement in the long focal length lens, and it is a problem to suppress the beam diameter and secure the focus sensitivity.

Although the optical system described in Patent Document 1 achieves a good reduction in the optical total length at the telephoto end, it is difficult to suppress the diameter of the lens barrel because the vibration isolation group has a large diameter and a low vibration isolation coefficient. Furthermore, the correction of axial chromatic aberration is insufficient and there is a problem in imaging performance.

The optical system described in Patent Document 2 has a telephoto ratio at the telephoto end of approximately 0.77, but it is desired to further shorten it. Furthermore, since the light diameter of the focus group is particularly high at the wide-angle end, a problem remains in the weight of the focus group.

The optical system described in Patent Document 3 corresponds to an image circle having a radius of about 11 mm, has a telephoto ratio of less than 0.65, and has a very short optical total length. However, there is no mention of image stabilization.

The optical system described in Patent Document 4 has a telephoto ratio of about 0.65 and a very short optical total length. However, the diameter of the anti-vibration group is too large, and it is difficult to reduce the weight even though the anti-vibration group has one structure. It is enough. In addition, the correction of the lateral chromatic aberration at the telephoto end is insufficient and there is a problem in performance.

The optical system described in Patent Document 5 has a telephoto ratio of about 0.65 and an optical total length that is very short, and the diameter of the antivibration group is suppressed, but the antivibration coefficient is small and the amount of movement of the antivibration group at the telephoto end is small. Is not suppressed, and the fluctuation of the coma aberration accompanying the shift of the anti-vibration group is particularly large, and the performance at the time of anti-vibration is not sufficient.

The present invention has been made in view of such a situation. In a variable magnification imaging optical system having a half angle of view at the telephoto end of about 2 degrees and a large image circle and a long focal length at the telephoto end, the total length is suppressed. An object of the present invention is to provide a high-performance variable magnification imaging optical system having an anti-vibration function that suppresses the weight of the anti-vibration group.

Therefore, in order to solve the above-mentioned problem, the invention described in claim 1
From the object side,
A first lens unit having a positive refractive power;
A second lens unit having negative refractive power;
Consists of a rear lens group with positive refractive power as a whole in the entire zoom range,
Each lens group is separated by an air interval, and the air interval between each lens group changes at the time of zooming,
The rear lens group is composed of at least two lens groups that move in independent orbits during zooming,
The second lens group is composed of a negative refractive power 2a group and a negative refractive power 2b group in order from the object side, and performs vibration isolation by displacing the 2b group in a direction perpendicular to the optical axis.
Group 2a has a lens component having a positive refractive power closest to the object side
A variable magnification imaging optical system having an anti-vibration function characterized by satisfying the following conditional expressions (1) and (2).
(1) 0.70 <| LT2a / f2a | <0.85
(2) −0.025 <dpp2a / | f2a | <−0.005
However,
LT2a is the distance from the most object side surface of 2a group to the image side focal point of 2a group,
f2a is the focal length of the group 2a,
dpp2a is the distance from the object side principal point of the group 2a to the image side principal point,
It is.

The invention according to claim 2
2. The variable magnification imaging optical system having an image stabilization function according to claim 1, wherein the second lens group is fixed with respect to the image plane at the time of zooming.

The invention according to claim 3
3. The zoom lens system according to claim 1, wherein the rear lens group includes a third lens group having a positive refractive power closest to the object side.

The invention according to claim 4
The rear lens group has a lens group having a negative refractive power closest to the image side,
4. A variable magnification imaging with an image stabilization function according to claim 3, wherein all or a part of any one of the rear lens groups excluding the third lens group is moved during focusing. An optical system was used.

According to the present invention, in the variable magnification imaging optical system with a half angle of view at the telephoto end of about 2 degrees and a large image circle and a long focal length at the telephoto end, the weight of the image stabilizing group is suppressed while suppressing the overall length. A variable magnification imaging optical system having an anti-vibration function can be provided.

It is a lens block diagram concerning Example 1 of an image formation optical system of the present invention. 6 is a longitudinal aberration diagram at an imaging distance infinity at the wide-angle end of the imaging optical system according to Example 1. FIG. FIG. 4 is a longitudinal aberration diagram at an imaging distance infinite at the middle telephoto position in the image forming optical system according to Example 1. FIG. 4 is a longitudinal aberration diagram at an imaging distance infinity at the telephoto end of the imaging optical system according to Example 1. 3 is a lateral aberration diagram at an imaging distance infinity at the wide angle end of the imaging optical system according to Example 1. FIG. FIG. 3 is a lateral aberration diagram at an imaging distance infinite at the middle telephoto position in the imaging optical system according to Example 1. 6 is a lateral aberration diagram at an imaging distance infinite at the telephoto end of the imaging optical system according to Example 1. FIG. 3 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the wide angle end of the imaging optical system according to Example 1. FIG. 6 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the middle telephoto position of the image forming optical system according to Example 1. FIG. 3 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the telephoto end of the image forming optical system according to Example 1. FIG. It is a lens block diagram which concerns on Example 2 of the imaging optical system of this invention. FIG. 6 is a longitudinal aberration diagram at an imaging distance infinity at the wide angle end of the imaging optical system according to Example 2. FIG. 7 is a longitudinal aberration diagram at an imaging distance infinite at the middle telephoto position in the image forming optical system according to Example 2. FIG. 6 is a longitudinal aberration diagram at an imaging distance infinite at the telephoto end of the image forming optical system according to Example 2. FIG. 7 is a lateral aberration diagram at an imaging distance infinity at the wide-angle end of the image forming optical system according to Example 2. FIG. 6 is a lateral aberration diagram at an intermediate telephoto shooting distance infinite distance in the image forming optical system according to Example 2. FIG. 6 is a lateral aberration diagram at an imaging distance infinite at the telephoto end of the image forming optical system according to Example 2. 6 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the wide angle end of the image forming optical system according to Example 2. FIG. 6 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the middle telephoto position of the image forming optical system according to Example 2. FIG. FIG. 6 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the telephoto end of the image forming optical system according to Example 2. It is a lens block diagram which concerns on Example 3 of the imaging optical system of this invention. FIG. 6 is a longitudinal aberration diagram at an imaging distance infinity at the wide angle end of the imaging optical system according to Example 3. FIG. 12 is a longitudinal aberration diagram at an imaging distance infinite at the middle telephoto position in the image forming optical system according to Example 3. FIG. 6 is a longitudinal aberration diagram at an imaging distance infinity at the telephoto end of the imaging optical system according to Example 3. FIG. 10 is a lateral aberration diagram at an imaging distance infinity at the wide angle end of the imaging optical system according to Example 3. FIG. 12 is a lateral aberration diagram at an intermediate telephoto shooting distance infinite distance in the image forming optical system according to Example 3. 6 is a lateral aberration diagram at an imaging distance infinite at the telephoto end of the imaging optical system according to Example 3. FIG. FIG. 10 is a transverse aberration diagram for the case of image stabilization of 0.3 ° at an imaging distance of infinity at the wide angle end of the imaging optical system according to Example 3. 10 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the middle telephoto position of the image forming optical system according to Example 3. FIG. FIG. 12 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the telephoto end of the imaging optical system according to Example 3. It is a lens block diagram which concerns on Example 4 of the imaging optical system of this invention. FIG. 6 is a longitudinal aberration diagram at an imaging distance infinity at the wide-angle end of the image forming optical system according to Example 4. FIG. 6 is a longitudinal aberration diagram at an imaging distance infinite at the middle telephoto position in the image forming optical system according to Example 4; FIG. 10 is a longitudinal aberration diagram at an imaging distance infinite at the telephoto end of the image forming optical system according to Example 4. FIG. 10 is a lateral aberration diagram at an imaging distance infinity at the wide-angle end of the image forming optical system according to Example 4. FIG. 10 is a lateral aberration diagram at an imaging distance infinite at the middle telephoto position in the image forming optical system according to Example 4. FIG. 10 is a lateral aberration diagram at an imaging distance infinite at the telephoto end of the image forming optical system according to Example 4. FIG. 10 is a lateral aberration diagram at the time of 0.3 ° image stabilization at an imaging distance infinity at the wide angle end of the imaging optical system according to Example 4. 10 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the middle telephoto position of the image forming optical system according to Example 4. FIG. FIG. 10 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the telephoto end of the image forming optical system according to Example 4. It is a lens block diagram which concerns on Example 5 of the imaging optical system of this invention. FIG. 10 is a longitudinal aberration diagram at an imaging distance infinity at the wide angle end of the imaging optical system according to Example 5. FIG. 10 is a longitudinal aberration diagram at an imaging distance infinity in the middle telephoto range of the image forming optical system according to Example 5. FIG. 11 is a longitudinal aberration diagram at an imaging distance infinity at the telephoto end of the imaging optical system according to Example 5. FIG. 10 is a transverse aberration diagram at an imaging distance infinity at the wide-angle end of the image forming optical system according to Example 5. FIG. 10 is a lateral aberration diagram at an imaging distance infinity in the middle telephoto range of the image forming optical system according to Example 5. FIG. 11 is a lateral aberration diagram at an imaging distance infinity at the telephoto end of the image forming optical system according to Example 5. FIG. 10 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the wide angle end of the imaging optical system according to Example 5. 10 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the middle telephoto position of the image forming optical system according to Example 5. FIG. FIG. 10 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the telephoto end of the image forming optical system according to Example 5. It is a lens block diagram which concerns on Example 6 of the imaging optical system of this invention. FIG. 11 is a longitudinal aberration diagram at an imaging distance infinity at the wide-angle end of the imaging optical system according to Example 6. FIG. 10 is a longitudinal aberration diagram at an imaging distance infinity in the middle telephoto range of the imaging optical system according to Example 6. FIG. 11 is a longitudinal aberration diagram at an imaging distance infinite at the telephoto end of the imaging optical system according to Example 6. FIG. 11 is a lateral aberration diagram at an imaging distance infinity at the wide-angle end of the image forming optical system according to Example 6. FIG. 10 is a lateral aberration diagram at an imaging distance infinity at the middle telephoto position in the image forming optical system according to Example 6. FIG. 10 is a lateral aberration diagram at an imaging distance infinite at the telephoto end of the imaging optical system according to Example 6. FIG. 10 is a lateral aberration diagram at the time of 0.3 ° image stabilization at an imaging distance infinity at the wide angle end of the imaging optical system according to Example 6. FIG. 10 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the middle telephoto position of the image forming optical system according to Example 6. 10 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an infinite shooting distance at the telephoto end of the image forming optical system according to Example 6. FIG. It is a lens block diagram which concerns on Example 7 of the imaging optical system of this invention. FIG. 10 is a longitudinal aberration diagram at an imaging distance infinity at the wide-angle end of the image forming optical system according to Example 7. FIG. 10 is a longitudinal aberration diagram at an imaging distance infinity in the middle telephoto range of the imaging optical system according to Example 7. FIG. 10 is a longitudinal aberration diagram at an imaging distance infinity at the telephoto end of the imaging optical system according to Example 7. FIG. 10 is a transverse aberration diagram at an imaging distance infinity at the wide-angle end of the image forming optical system according to Example 7. FIG. 10 is a lateral aberration diagram at an imaging distance infinity in the middle telephoto range of the imaging optical system according to Example 7. FIG. 11 is a lateral aberration diagram at an imaging distance infinity at the telephoto end of the imaging optical system according to Example 7. 10 is a transverse aberration diagram for the case of image stabilization of 0.3 ° at an imaging distance of infinity at the wide angle end of the imaging optical system according to Example 7. FIG. FIG. 10 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the middle telephoto position of the image forming optical system according to Example 7. FIG. 10 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the telephoto end of the imaging optical system according to Example 7. It is a lens block diagram which concerns on Example 8 of the imaging optical system of this invention. FIG. 10 is a longitudinal aberration diagram at an imaging distance infinity at the wide-angle end of the image forming optical system according to Example 8. FIG. 10 is a longitudinal aberration diagram at an imaging distance infinity in the middle telephoto range of the imaging optical system according to Example 8. FIG. 10 is a longitudinal aberration diagram at an imaging distance infinity at the telephoto end of the imaging optical system according to Example 8. FIG. 10 is a lateral aberration diagram at an imaging distance infinity at the wide-angle end of the image forming optical system according to Example 8. FIG. 10 is a transverse aberration diagram at an imaging distance infinity in the middle telephoto range of the image forming optical system according to Example 8. FIG. 10 is a lateral aberration diagram at an imaging distance infinity at the telephoto end of the image forming optical system according to Example 8. FIG. 10 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the wide angle end of the imaging optical system according to Example 8. FIG. 10 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the middle telephoto position of the image forming optical system according to Example 8. FIG. 10 is a lateral aberration diagram at the time of image stabilization of 0.3 ° at an imaging distance of infinity at the telephoto end of the imaging optical system according to Example 8.

The variable magnification imaging optical system having the image stabilization function according to the present invention includes an object as shown in each lens configuration diagram shown in FIGS. 1, 11, 21, 31, 41, 51, 61, and 71. The first lens unit having a positive refractive index in order from the side, the second lens unit having a negative refractive power, and at least two rear lens units following the second lens unit are positive as a whole over the entire zoom range. It consists of a rear lens group having a refractive power of.

The lens groups are separated by an air gap, and the distance between the lens groups changes during zooming. The second lens group includes a negative refractive power 2a group and a negative refractive power 2b group in order from the object side, and performs vibration isolation by displacing the 2b group in a direction perpendicular to the optical axis. The group 2a has a lens component having a positive refractive power closest to the object side, and is configured to satisfy a predetermined conditional expression.

In order to suppress the overall length while increasing the focal length at the telephoto end, a first lens group having a positive refractive power and a second lens group having a negative refractive power are arranged in this order from the object side, so that a telephoto type refractive power arrangement is achieved. It is composed.

The zooming from the wide-angle end to the telephoto end is performed mainly by increasing the distance between the first lens group and the second lens group.

Further, with the zooming from the wide angle end to the telephoto end, the distance between the second lens group and the rear lens group decreases, and the refractive power of the combined system of the second lens group and the rear lens group changes in the negative direction. By this action, the telephoto refractive power arrangement formed by the combined system of the first lens group, the second lens group, and the rear lens group becomes stronger from the wide-angle end toward the telephoto end. At the wide angle end, the total length of the optical system is relatively long with respect to the total focal length of the entire system, and at the telephoto end, the total length of the optical system is relatively short with respect to the total focal length of the entire system. Can be suppressed.

The second lens group has a significantly smaller beam diameter than the first lens group, and is suitable for reducing the weight of the anti-vibration group by using it as an anti-vibration group. Further, the second lens group is divided into the 2a group and the 2b group in order from the object side, and only the 2b group having a lower light beam diameter disposed on the image side is used for the image stabilization, thereby further reducing the weight of the image stabilization group. Suitable.

A lens component having a positive refractive power is arranged on the most object side of the group 2a. In order to obtain a negative refractive power as a whole of the 2a group, a lens component having a negative refractive power is necessarily arranged on the image side. By adopting such an arrangement, the 2a group itself is configured to have a telescopic refractive power arrangement. Due to the effect of this arrangement, while the overall length of the entire optical system is shortened, the axial ray diameter emitted from the 2a group can be reduced to reduce the axial ray diameter in the 2b group which is the antivibration group. It is effective for weight reduction.

Shortening the total length of the entire optical system can also be achieved by increasing the refractive power of the front portion having positive refractive power and the rear portion having negative refractive power. However, since the refractive power of each group becomes strong, the occurrence of aberrations in each group increases. In particular, by increasing the refractive power of the positive group in front of the stop and the negative group behind the stop, it is difficult to correct lateral chromatic aberration and suppress fluctuations during zooming, making it difficult to maintain the performance of the entire system. .

Taking a configuration with a small telephoto ratio in the 2a group with no aperture in between is also effective in maintaining performance while shortening the overall length.

Conditional expression (1) defines the telephoto ratio of the 2a group, and indicates a desirable range for shortening the entire optical system and reducing the weight of the image stabilizing group.

If the upper limit of conditional expression (1) is exceeded and the telephoto ratio of the group 2a is increased, the total length is shortened and the light beam diameter of the group 2b is not sufficiently suppressed, and the weight reduction of the vibration-proof group is also insufficient.

If the lower limit of conditional expression (1) is exceeded and the telephoto ratio of the 2a group becomes small, the effect of shortening the total length and suppressing the beam diameter increases, but the refractive power of the lens component having the positive refractive power closest to the object is strong. As a result, the variation of astigmatism due to the tilt of the lens tends to increase, and the performance degradation due to manufacturing errors increases.

The upper limit of conditional expression (1) is set to 0.83, further 0.82, and the lower limit of conditional expression (1) is set to 0.71, and further to 0.72, the effect of the present invention can be achieved more reliably. can do.

Conditional expression (2) defines the interval between the two principal points of the group 2a, and indicates a desirable range for shortening the entire optical system and reducing the weight of the image stabilizing group.

Since the object side principal point of the group 2a is positioned on the image side with respect to the image side principal point, the overall length of the entire optical system can be shortened. In addition, since the axial beam diameter can be reduced in a shorter section, the beam diameter of the 2b group can be suppressed while reducing the overall length.

If the upper limit of conditional expression (2) is exceeded, the object side principal point is positioned too much on the object side with respect to the image side principal point, and the total length is shortened and the light beam diameter is not sufficiently suppressed.

If the lower limit of conditional expression (2) is not reached, the effect of shortening the total length and suppressing the beam diameter will be high, but the refractive power of the lens component having the most positive refractive power on the object side will be too strong, resulting in non-reduction due to lens tilt. The variation of the point aberration tends to be large, and the performance deterioration due to the manufacturing error becomes large.

By setting the upper limit of conditional expression (2) to -0.008, further to -0.010, and the lower limit of conditional expression (2) to -0.022 and further to -0.020, the effect of the present invention can be obtained. It can be achieved more reliably.

In the variable magnification imaging optical system having the image stabilization function of the present invention, it is desirable that the second lens group is fixed with respect to the image plane at the time of zooming. This is because the second lens group includes an anti-vibration group, and thus it is necessary to connect a control wiring. When the second lens group moves, it is connected by a flexible wiring, and in order not to apply excessive stress to the flexible wiring along with the movement of the second lens group, a space for deflecting and retracting the flexible wiring is required. In order to secure the space, it is difficult to reduce the size of the entire lens barrel.

In the variable magnification imaging optical system having the image stabilization function of the present invention, it is desirable to include a third lens group having a positive refractive power on the most object side of the rear lens group. By making the third lens group having a positive refractive power approach the second lens group having a negative refractive power at the telephoto end, the negative refraction of the combined system of the second lens group and the third lens group at the telephoto end is achieved. The force can be increased, the total optical length at the telephoto end can be shortened, and this is effective in suppressing the amount of movement of the first lens group.

In the variable magnification imaging optical system having the image stabilization function of the present invention, it is desirable to move all or a part of any one of the lens groups excluding the third lens group in the rear lens group during focusing. .

In the long focus lens, the defocus amount for focusing to a short distance becomes large. Considering the improvement of the autofocus drive speed, two points are achieved: first, the focusing lens group is lightweight, and second, the amount of movement of the image plane relative to the unit movement amount of the focusing lens group is large. It is desirable.

In the long focal length optical system, the outer diameter is too large to use the portion close to the object side for focusing, and the weight cannot be suppressed at all. In the variable magnification imaging optical system of the present invention, the light beam is converged by the first lens group, diverged by the second lens group, and converged by the third lens group. Therefore, if the lens group is further rearward than the third lens group in the rear lens group, the luminous flux is sufficiently converged, and a sufficient weight reduction is possible.

In order to shorten the entire optical system, it is desirable that the lens group closest to the image side of the optical system has a strong negative refractive power. Due to this strong negative refractive power, the imaging magnification of the lens group closest to the image side becomes large. Therefore, in the whole or part of the lens group closest to the image side, or in the whole or part of the lens group closer to the object side than the lens group closest to the image side, the image plane movement amount per unit movement amount of the lens group is Easy to grow.

From these properties, it is desirable to perform focusing by the whole or a part of any one of the lens groups except the third lens group located closest to the object side in the rear lens group.

Next, a lens configuration of an example according to the imaging optical system of the present invention will be described.
In the following description, the lens configuration is described in order from the object side to the image side.

FIG. 1 is a lens configuration diagram of an imaging optical system according to Example 1 of the present invention.

In order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and The fifth lens group G5 has a negative refractive power.

A synthesis system from the third lens group G3 to the fifth lens group G5 corresponds to the rear lens group Gr.

The first lens group G1 includes a negative meniscus lens L1 having a convex surface facing the object side, a biconvex lens L2, and a positive meniscus lens L3 having a convex surface facing the object side.

The second lens group includes a negative refractive power 2a group and a negative refractive power 2b group in order from the object side, and performs vibration isolation by displacing only the 2b group in a direction perpendicular to the optical axis.

The group 2a includes a positive meniscus lens L4 having a convex surface directed toward the object side, and a cemented lens including a biconvex lens L5 and a biconcave lens L6.

The 2b group includes a biconcave lens L7 and a cemented lens including a biconcave lens L8 and a biconvex lens L9.

The third lens group G3 includes a biconvex lens L10, a cemented lens including a biconvex lens L11 and a biconcave lens L12, a positive meniscus lens L13 having a convex surface facing the object side, a negative meniscus lens L14 having a convex surface facing the object side, Consists of

The aperture stop is provided on the image side of the third lens group, and moves together with the third lens group with zooming.

The fourth lens group G4 includes a biconvex lens L15, a cemented lens including a negative meniscus lens L16 having a convex surface directed toward the image side, and a positive meniscus lens L17 having a convex surface directed toward the object side. The entire fourth lens group G4 moves toward the object side during focusing from infinity to a short distance.

The fifth lens group G5 includes a negative meniscus lens L18 having a convex surface directed toward the object side, and a cemented lens including a biconcave lens L19 and a biconvex lens L20.

FIG. 11 is a lens configuration diagram of the imaging optical system according to Example 2 of the present invention.

In order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and The fifth lens group G5 has a negative refractive power.

A synthesis system from the third lens group G3 to the fifth lens group G5 corresponds to the rear lens group Gr.

The first lens group G1 includes a cemented lens including a negative meniscus lens L1 having a convex surface facing the object side and a biconvex lens L2, and a plano-convex lens L3 having a convex surface facing the object side.

The second lens group includes a negative refractive power 2a group and a negative refractive power 2b group in order from the object side, and performs vibration isolation by displacing only the 2b group in a direction perpendicular to the optical axis.

The group 2a includes a positive meniscus lens L4 having a convex surface directed toward the object side, and a cemented lens including a biconvex lens L5 and a biconcave lens L6.

The 2b group includes a biconcave lens L7 and a cemented lens including a biconcave lens L8 and a biconvex lens L9.

The third lens group G3 includes a biconvex lens L10, a cemented lens including a biconvex lens L11 and a biconcave lens L12, a positive meniscus lens L13 having a convex surface facing the object side, a negative meniscus lens L14 having a convex surface facing the object side, Consists of

The aperture stop is provided on the image side of the third lens group, and moves together with the third lens group with zooming.

The fourth lens group G4 includes a biconvex lens L15, a cemented lens including a negative meniscus lens L16 having a convex surface directed toward the image side, and a positive meniscus lens L17 having a convex surface directed toward the object side. The entire fourth lens group G4 moves toward the object side during focusing from infinity to a short distance.

The fifth lens group G5 includes a negative meniscus lens L18 having a convex surface directed toward the object side, and a cemented lens including a biconcave lens L19 and a biconvex lens L20.

FIG. 21 is a lens configuration diagram of the imaging optical system according to Example 3 of the present invention.

In order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and The fifth lens group G5 has a negative refractive power.

A synthesis system from the third lens group G3 to the fifth lens group G5 corresponds to the rear lens group Gr.

The first lens group G1 includes a negative meniscus lens L1 having a convex surface facing the object side, a biconvex lens L2, and a positive meniscus lens L3 having a convex surface facing the object side.

The second lens group includes a negative refractive power 2a group and a negative refractive power 2b group in order from the object side, and performs vibration isolation by displacing only the 2b group in a direction perpendicular to the optical axis.

The group 2a includes a positive meniscus lens L4 having a convex surface directed toward the object side, and a cemented lens including a biconvex lens L5 and a biconcave lens L6.

The 2b group includes a biconcave lens L7 and a cemented lens including a biconcave lens L8 and a biconvex lens L9.

The third lens group G3 includes a biconvex lens L10, a cemented lens including a biconvex lens L11 and a biconcave lens L12, a positive meniscus lens L13 having a convex surface facing the object side, a negative meniscus lens L14 having a convex surface facing the object side, Consists of

The aperture stop is provided on the image side of the third lens group, and moves together with the third lens group with zooming.

The fourth lens group G4 includes a biconvex lens L15, a cemented lens including a negative meniscus lens L16 having a convex surface directed toward the image side, and a positive meniscus lens L17 having a convex surface directed toward the object side. The entire fourth lens group G4 moves toward the object side during focusing from infinity to a short distance.

The fifth lens group G5 includes a negative meniscus lens L18 having a convex surface directed toward the object side, and a cemented lens including a biconcave lens L19 and a biconvex lens L20.

FIG. 31 is a lens configuration diagram of the imaging optical system according to Example 4 of the present invention.

In order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and The fifth lens group G5 has a negative refractive power.

A synthesis system from the third lens group G3 to the fifth lens group G5 corresponds to the rear lens group Gr.

The first lens group G1 includes a cemented lens including a negative meniscus lens L1 having a convex surface facing the object side and a biconvex lens L2, and a plano-convex lens L3 having a convex surface facing the object side.

The second lens group includes a negative refractive power 2a group and a negative refractive power 2b group in order from the object side, and performs vibration isolation by displacing only the 2b group in a direction perpendicular to the optical axis.

The group 2a includes a positive meniscus lens L4 having a convex surface directed toward the object side, and a cemented lens including a biconvex lens L5 and a biconcave lens L6.

The group 2b includes a cemented lens including a biconcave lens L7, a biconcave lens L8, and a positive meniscus lens L9 having a convex surface directed toward the object side.

The third lens group G3 includes a biconvex lens L10, a cemented lens including a biconvex lens L11 and a biconcave lens L12, a positive meniscus lens L13 having a convex surface facing the object side, a negative meniscus lens L14 having a convex surface facing the object side, Consists of

The aperture stop is provided on the image side of the third lens group, and moves together with the third lens group with zooming.

The fourth lens group G4 includes a biconvex lens L15, a cemented lens including a negative meniscus lens L16 having a convex surface directed toward the image side, and a positive meniscus lens L17 having a convex surface directed toward the object side.

The fifth lens group G5 includes a cemented lens including a negative meniscus lens L18 having a convex surface directed toward the object side, a biconcave lens L19, and a positive meniscus L20 having a convex surface directed toward the object side.
The entire fifth lens group G5 moves toward the image side during focusing from infinity to a short distance.

FIG. 41 is a lens configuration diagram of the imaging optical system according to Example 5 of the present invention.

In order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and The fifth lens group G5 has a negative refractive power.

A synthesis system from the third lens group G3 to the fifth lens group G5 corresponds to the rear lens group Gr.

The first lens group G1 includes a cemented lens including a negative meniscus lens L1 having a convex surface facing the object side and a biconvex lens L2, and a plano-convex lens L3 having a convex surface facing the object side.

The second lens group includes a negative refractive power 2a group and a negative refractive power 2b group in order from the object side, and performs vibration isolation by displacing only the 2b group in a direction perpendicular to the optical axis.

The group 2a includes a positive meniscus lens L4 having a convex surface directed toward the object side, and a cemented lens including a biconvex lens L5 and a biconcave lens L6.

The group 2b includes a cemented lens including a biconcave lens L7, a biconcave lens L8, and a positive meniscus lens L9 having a convex surface directed toward the object side.

The third lens group G3 includes a biconvex lens L10, a cemented lens including a biconvex lens L11 and a biconcave lens L12, a positive meniscus lens L13 having a convex surface facing the object side, a negative meniscus lens L14 having a convex surface facing the object side, Consists of

The aperture stop is provided on the image side of the third lens group, and moves together with the third lens group with zooming.

The fourth lens group G4 includes a biconvex lens L15, a cemented lens including a negative meniscus lens L16 having a convex surface directed toward the image side, and a positive meniscus lens L17 having a convex surface directed toward the object side.

The fifth lens group G5 includes a cemented lens including a negative meniscus lens L18 having a convex surface directed toward the object side, a biconcave lens L19, and a positive meniscus lens L20 having a convex surface directed toward the object side. The entire fifth lens group G5 moves toward the image side during focusing from infinity to a short distance.

FIG. 51 is a lens configuration diagram of the imaging optical system according to Example 6 of the present invention.

In order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and The fifth lens group G5 has a negative refractive power.

A synthesis system from the third lens group G3 to the fifth lens group G5 corresponds to the rear lens group Gr.

The first lens group G1 includes a cemented lens including a negative meniscus lens L1 having a convex surface facing the object side and a biconvex lens L2, and a plano-convex lens L3 having a convex surface facing the object side.

The second lens group includes a negative refractive power 2a group and a negative refractive power 2b group in order from the object side, and performs vibration isolation by displacing only the 2b group in a direction perpendicular to the optical axis.

The group 2a includes a positive meniscus lens L4 having a convex surface directed toward the object side, and a cemented lens including a biconvex lens L5 and a biconcave lens L6.

The group 2b includes a cemented lens including a biconcave lens L7, a biconcave lens L8, and a positive meniscus lens L9 having a convex surface directed toward the object side.

The third lens group G3 includes a biconvex lens L10, a cemented lens including a biconvex lens L11 and a biconcave lens L12, a positive meniscus lens L13 having a convex surface facing the object side, a negative meniscus lens L14 having a convex surface facing the object side, Consists of

The aperture stop is provided on the image side of the third lens group, and moves together with the third lens group with zooming.

The fourth lens group G4 includes a biconvex lens L15, a cemented lens including a negative meniscus lens L16 having a convex surface directed toward the image side, and a biconvex lens L17.

The fifth lens group G5 includes a negative refractive power 5a group and a negative refractive power 5b group. The group 5a includes a negative meniscus lens L18 having a convex surface facing the object side and a positive meniscus lens L19 having a convex surface facing the object side.

The 5b group includes a cemented lens including a biconcave lens L20 and a positive meniscus lens L21 having a convex surface directed toward the object side. The group 5b moves to the image side during focusing from an infinite distance to a short distance.

FIG. 61 is a lens configuration diagram of the imaging optical system according to Example 7 of the present invention.

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, the third lens group G3 having a positive refractive power, the fourth lens group G4 having a positive refractive power, and a negative The fifth lens group G5 having a negative refractive power and the sixth lens group G6 having a negative refractive power.

A synthesis system from the third lens group G3 to the sixth lens group G6 corresponds to the rear lens group Gr.

The first lens group G1 includes a cemented lens including a negative meniscus lens L1 having a convex surface facing the object side and a biconvex lens L2, and a plano-convex lens L3 having a convex surface facing the object side.

The second lens group includes a negative refractive power 2a group and a negative refractive power 2b group in order from the object side, and performs vibration isolation by displacing only the 2b group in a direction perpendicular to the optical axis.

The group 2a includes a positive meniscus lens L4 having a convex surface directed toward the object side, and a cemented lens including a biconvex lens L5 and a biconcave lens L6.

The group 2b includes a cemented lens including a biconcave lens L7, a biconcave lens L8, and a positive meniscus lens L9 having a convex surface directed toward the object side.

The third lens group G3 includes a biconvex lens L10, a cemented lens including a biconvex lens L11 and a negative meniscus lens L12 having a convex surface facing the image side, a positive meniscus lens L13 having a convex surface facing the object side, and a convex surface facing the object side. And a negative meniscus lens L14 directed.

The aperture stop is provided on the image side of the third lens group, and moves together with the third lens group with zooming.

The fourth lens group G4 includes a biconvex lens L15, a cemented lens including a negative meniscus lens L16 having a convex surface directed toward the image side, and a biconvex lens L17.

The fifth lens group G5 includes a negative meniscus lens L18 having a convex surface directed toward the object side, and a positive meniscus lens L19 having a convex surface directed toward the object side. The fifth lens group G5 moves to the image side during focusing from infinity to a short distance.

The sixth lens group G6 includes a cemented lens including a biconcave lens L20 and a positive meniscus lens L21 having a convex surface directed toward the object side.

FIG. 71 is a lens configuration diagram of the imaging optical system according to Example 8 of the present invention.

In order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and The fifth lens group G5 has a negative refractive power.

A synthesis system from the third lens group G3 to the fifth lens group G5 corresponds to the rear lens group Gr.

The first lens group G1 includes a negative meniscus lens L1 having a convex surface facing the object side, a biconvex lens L2, and a positive meniscus lens L3 having a convex surface facing the object side.

The second lens group includes a negative refractive power 2a group and a negative refractive power 2b group in order from the object side, and performs vibration isolation by displacing only the 2b group in a direction perpendicular to the optical axis.

The group 2a includes a positive meniscus lens L4 having a convex surface directed toward the object side, and a cemented lens including a biconvex lens L5 and a biconcave lens L6.

The 2b group includes a biconcave lens L7 and a cemented lens including a biconcave lens L8 and a biconvex lens L9.

The third lens group G3 includes a biconvex lens L10, a cemented lens including a biconvex lens L11 and a biconcave lens L12, a positive meniscus lens L13 having a convex surface facing the object side, a negative meniscus lens L14 having a convex surface facing the object side, Consists of

The aperture stop is provided on the image side of the third lens group, and moves together with the third lens group with zooming.

The fourth lens group G4 includes a biconvex lens L15, a cemented lens including a negative meniscus lens L16 having a convex surface directed toward the image side, and a positive meniscus lens L17 having a convex surface directed toward the object side. The entire fourth lens group G4 moves toward the object side during focusing from infinity to a short distance.

The fifth lens group G5 includes a negative meniscus lens L18 having a convex surface directed toward the object side, and a cemented lens including a biconcave lens L19 and a biconvex lens L20.

Specific numerical data of each embodiment of the imaging optical system of the present invention described above will be shown below.

In [Surface data], the surface number is the number of the lens surface or aperture stop counted from the object side, r is the radius of curvature of each surface, d is the distance between the surfaces, nd is the refractive index with respect to the d-line (wavelength 587.56 nm). , Vd indicate Abbe numbers for the d line.

The (diaphragm) attached to the surface number indicates that the aperture stop is located at that position. ∞ (infinity) is entered in the radius of curvature for a plane or aperture stop. BF represents back focus.

[Various data] shows values such as the focal length in each shooting distance state.

[Variable interval data] indicates the variable interval and the value of BF in each shooting distance state.

[Lens Group Data] indicates the surface number of the most object side constituting each lens group and the combined focal length of the entire group.

In all the values of the following specifications, the focal length f, the radius of curvature r, the lens surface interval d, and other length units described are in millimeters (mm) unless otherwise specified. In the system, the same optical performance can be obtained even in proportional expansion and proportional reduction, and the present invention is not limited to this.

  In addition, a list of corresponding values of the conditional expressions in each of these examples is shown.

  In the aberration diagrams corresponding to each example, d, g, and C represent d-line, g-line, and C-line, respectively, and ΔS and ΔM represent sagittal image plane and meridional image plane, respectively. .

Numerical example 1
Unit: mm
[Surface data]
Surface number rd nd vd
1 357.6638 3.0000 1.80611 40.73
2 145.8989 0.1000
3 145.8989 10.7551 1.49700 81.61
4 -794.0595 0.1500
5 135.5390 10.1849 1.43700 95.10
6 7136.8093 (d6)
7 137.9806 3.0791 1.72916 54.67
8 758.9464 20.2528
9 299.5544 2.6811 1.56732 42.84
10 -133.6568 1.0000 1.77250 49.62
11 92.0241 6.0917
12 -162.5813 0.8000 1.69680 55.46
13 83.9180 3.0070
14 -56.0081 0.8000 1.69680 55.46
15 74.4381 2.9326 1.80518 25.46
16 -271.5499 (d16)
17 297.4981 3.8735 1.69680 55.46
18 -72.3818 0.1500
19 63.0217 5.0039 1.49700 81.61
20 -56.2842 1.0000 1.90043 37.37
21 325.1721 0.1500
22 33.0876 4.2056 1.62004 36.30
23 102.9453 2.4546
24 46.7524 1.0000 1.91082 35.25
25 28.9828 5.7612
26 (Aperture) ∞ (d26)
27 150.4164 4.1498 1.58913 61.25
28 -35.3902 1.0000 1.95375 32.32
29 -66.3121 0.1500
30 60.0137 2.5699 1.58913 61.25
31 439.8894 (d31)
32 78.1384 1.0000 1.90043 37.37
33 30.9430 8.3296
34 -75.9406 1.0000 1.49700 81.61
35 32.0303 4.0594 1.64769 33.84
36 -260.4427 (BF)
Image plane ∞

[Various data]
Zoom ratio 3.75
Wide angle Medium telephoto
Focal length 154.54 270.00 578.90
F number 5.20 5.81 6.51
Full angle 2ω 15.63 8.97 4.19
Image height Y 21.63 21.63 21.63
Total lens length 298.6040 342.3965 377.7921

[Variable interval data]
Wide angle Medium telephoto
d6 47.8371 91.6295 127.0254
d16 32.3023 26.1575 3.5000
d26 30.1327 15.9882 22.9567
d31 14.6883 8.4186 1.9977
BF 62.9518 89.5109 111.6205

[Lens group data]
Group Start surface Focal length
G1 1 255.26
G2 7 -46.06
G3 17 72.20
G4 27 60.80
G5 32 -60.88
G2a 7 -357.47
G2b 12 -48.13

Numerical example 2
Unit: mm
[Surface data]
Surface number rd nd vd
1 528.6730 3.0000 1.83481 42.72
2 143.5131 10.5261 1.49700 81.61
3 -536.1702 0.1500
4 133.2008 9.3074 1.49700 81.61
5 ∞ (d5)
6 148.9229 2.9114 1.71736 29.50
7 700.0000 22.6935
8 165.3603 2.7965 1.51742 52.15
9 -165.3603 1.0000 1.88300 40.80
10 93.6370 6.0627
11 -250.0754 0.7000 1.69680 55.46
12 92.3831 2.8270
13 -57.3765 0.7000 1.69680 55.46
14 75.3753 2.7812 1.80518 25.46
15 -472.9495 (d15)
16 284.2091 3.3355 1.69680 55.46
17 -67.7648 0.1500
18 70.9155 5.0947 1.49700 81.61
19 -53.8213 1.0000 1.90043 37.37
20 337.6022 0.1500
21 34.4130 5.7994 1.58144 40.89
22 96.3145 1.3784
23 45.9295 1.9000 1.88100 40.14
24 30.4137 5.5139
25 (Aperture) ∞ (d25)
26 160.1209 4.1084 1.65844 50.85
27 -35.9129 1.0000 1.95375 32.32
28 -80.1123 0.1500
29 67.7459 2.2114 1.58913 61.25
30 554.6238 (d30)
31 63.9746 1.0000 1.91082 35.25
32 29.1749 8.7771
33 -72.7482 1.0000 1.43700 95.10
34 31.9872 4.5267 1.64769 33.84
35 -1000.0000 (BF)
Image plane ∞

[Various data]
Zoom ratio 3.74
Wide angle Medium telephoto
Focal length 154.67 270.00 578.86
F number 5.15 5.77 6.50
Full angle of view 2ω 15.58 8.96 4.19
Image height Y 21.63 21.63 21.63
Total lens length 298.9062 343.6742 379.0453

[Variable interval data]
Wide angle Medium telephoto
d5 48.3963 93.1642 128.5354
d15 30.4954 25.6247 3.5000
d25 34.1791 19.6736 24.9615
d30 18.4411 9.9704 1.9974
BF 54.8430 82.6900 107.4997

[Lens group data]
Group Start surface Focal length
G1 1 256.25
G2 6 -46.11
G3 16 71.10
G4 26 65.07
G5 31 -65.77
G2a 6 -267.24
G2b 11 -51.20

Example 3
Unit: mm
[Surface data]
Surface number rd nd vd
1 373.7120 3.0000 1.80611 40.73
2 148.6143 0.1000
3 148.6143 10.6839 1.49700 81.61
4 -731.3819 0.1500
5 137.0582 10.1463 1.43700 95.10
6 14951.7522 (d6)
7 116.0743 4.0892 1.72916 54.67
8 403.7009 20.7778
9 293.4642 3.6165 1.56732 42.84
10 -123.6305 1.6647 1.77250 49.62
11 71.3448 6.3805
12 -145.4433 0.8000 1.69680 55.46
13 104.6635 2.6947
14 -60.2911 0.8000 1.69680 55.46
15 72.6162 2.9409 1.80518 25.46
16 -297.3883 (d16)
17 312.8853 3.8974 1.69680 55.46
18 -71.2933 0.1500
19 62.7609 5.0466 1.49700 81.61
20 -56.5939 1.0000 1.90043 37.37
21 324.7258 0.1500
22 33.4685 4.1701 1.62004 36.30
23 101.2724 2.7853
24 46.3806 1.0000 1.91082 35.25
25 29.1987 5.7625
26 (Aperture) ∞ (d26)
27 141.0544 4.1662 1.58913 61.25
28 -36.0830 1.0000 1.95375 32.32
29 -68.3457 0.1500
30 59.9188 2.5555 1.58913 61.25
31 391.7408 (d31)
32 75.5933 1.0000 1.90043 37.37
33 30.9362 9.3376
34 -80.2760 1.0000 1.49700 81.61
35 31.7778 4.0939 1.64769 33.84
36 -337.4440 (BF)
Image plane ∞

[Various data]
Zoom ratio 3.74
Wide angle Medium telephoto
Focal length 154.65 269.99 578.93
F number 5.18 5.80 6.48
Full angle of view 2ω 15.66 8.98 4.19
Image height Y 21.63 21.63 21.63
Total lens length 298.6675 342.4427 378.4134

[Variable interval data]
Wide angle Medium telephoto
d6 43.8852 87.6604 123.6307
d16 32.2743 25.7705 3.5000
d26 30.3672 16.5059 23.1094
d31 14.2104 8.2370 1.9975
BF 62.8208 89.1593 111.0662

[Lens group data]
Group Start surface Focal length
G1 1 255.76
G2 7 -45.76
G3 17 71.22
G4 27 61.27
G5 32 -61.45
G2a 7 -213.69
G2b 12 -52.85

Example 4
Unit: mm
[Surface data]
Surface number rd nd vd
1 378.1538 3.0000 1.83481 42.72
2 129.8799 10.1967 1.49700 81.61
3 -1207.9001 0.1500
4 128.8993 9.5152 1.49700 81.61
5 ∞ (d5)
6 136.4357 2.9694 1.71736 29.50
7 520.1053 22.5262
8 157.9367 2.8856 1.51742 52.15
9 -157.9367 1.0000 1.88300 40.80
10 96.4016 6.0478
11 -343.4654 0.7000 1.69680 55.46
12 84.3415 2.7699
13 -64.5497 0.7000 1.69680 55.46
14 63.5386 2.7771 1.80518 25.46
15 2214.2403 (d15)
16 320.9977 3.3148 1.69680 55.46
17 -66.4937 0.1500
18 72.1850 5.0395 1.49700 81.61
19 -54.1974 1.0000 1.90043 37.37
20 347.1276 0.1500
21 34.9884 5.4911 1.58144 40.89
22 100.1616 0.9803
23 46.2672 1.9000 1.88100 40.14
24 30.8087 5.5414
25 (Aperture) ∞ (d25)
26 184.7128 4.1778 1.65844 50.85
27 -36.1480 1.0000 1.95375 32.32
28 -77.2303 0.1500
29 71.5466 2.3326 1.58913 61.25
30 1830.4119 (d30)
31 77.3392 1.0000 1.91082 35.25
32 32.1806 10.2760
33 -78.1132 1.6681 1.43700 95.10
34 36.1981 4.4142 1.67270 32.17
35 10228.2235 (BF)
Image plane ∞

[Various data]
Zoom ratio 3.74
Wide angle Medium telephoto
Focal length 154.65 269.95 578.87
F number 5.07 5.83 6.50
Full angle of view 2ω 15.71 9.03 4.21
Image height Y 21.63 21.63 21.63
Total lens length 298.9917 341.5260 379.1790

[Variable interval data]
Wide angle Medium telephoto
d5 47.3884 89.9225 127.5760
d15 29.5144 24.3542 3.5000
d25 36.9826 19.2524 19.9625
d30 19.1013 10.5429 1.9972
BF 52.1813 83.6303 112.3196

[Lens group data]
Group Start surface Focal length
G1 1 257.80
G2 6 -46.22
G3 16 71.96
G4 26 64.13
G5 31 -65.81
G2a 6 -299.30
G2b 11 -49.93

Example 5
Unit: mm
[Surface data]
Surface number rd nd vd
1 373.2439 3.0000 1.83481 42.72
2 128.8795 10.2630 1.49700 81.61
3 -1288.9145 0.1500
4 128.2438 9.6096 1.49700 81.61
5 ∞ (d5)
6 137.6764 2.9639 1.71736 29.50
7 544.3756 22.6620
8 149.6888 2.9567 1.51742 52.15
9 -149.6888 1.0000 1.88300 40.80
10 94.6010 6.0666
11 -314.7976 0.7000 1.69680 55.46
12 86.0375 2.7411
13 -64.5500 0.7000 1.69680 55.46
14 64.5618 2.7794 1.80518 25.46
15 5702.1522 (d15)
16 346.2888 3.2611 1.69680 55.46
17 -67.4490 0.1500
18 75.1045 4.9850 1.49700 81.61
19 -54.3536 1.0000 1.90043 37.37
20 388.8141 0.1500
21 35.6793 4.7690 1.58144 40.89
22 107.1754 1.0796
23 47.2787 1.9000 1.88100 40.14
24 31.5149 5.5389
25 (Aperture) ∞ (d25)
26 198.8545 4.1456 1.65844 50.85
27 -36.1922 1.0000 1.95375 32.32
28 -75.7005 0.1500
29 69.5985 2.3143 1.59349 67.00
30 1112.9818 (d30)
31 75.6091 1.0000 1.90043 37.37
32 32.3743 11.1880
33 -83.0905 1.0000 1.43700 95.10
34 36.5367 4.2928 1.67270 32.17
35 674.4266 (BF)
Image plane ∞

[Various data]
Zoom ratio 3.74
Wide angle Medium telephoto
Focal length 154.65 269.99 578.88
F number 5.04 5.86 6.49
Full angle of view 2ω 15.71 9.03 4.21
Image height Y 21.63 21.63 21.63
Total lens length 299.0765 340.6390 379.3817

[Variable interval data]
Wide angle Medium telephoto
d5 46.8751 88.4376 127.1801
d15 28.9404 23.7846 3.5000
d25 38.1845 19.9778 21.7946
d30 19.5085 10.9735 1.9975
BF 52.0514 83.9489 111.3929

[Lens group data]
Group Start surface Focal length
G1 1 257.64
G2 6 -46.46
G3 16 73.66
G4 26 63.71
G5 31 -64.70
G2a 6 -292.50
G2b 11 -50.41

Example 6
Unit: mm
[Surface data]
Surface number rd nd vd
1 365.4891 3.0000 1.83481 42.72
2 127.0846 10.3046 1.49700 81.61
3 -1427.5505 0.1500
4 127.1046 9.6873 1.49700 81.61
5 ∞ (d5)
6 144.9780 3.0032 1.71736 29.50
7 709.8099 22.5926
8 139.7435 3.0697 1.51742 52.15
9 -139.7435 1.0000 1.88300 40.80
10 91.2159 6.1098
11 -305.2438 0.7000 1.69680 55.46
12 87.7611 2.7308
13 -64.5798 0.7000 1.69680 55.46
14 66.8529 2.7379 1.80518 25.46
15 6415.1292 (d15)
16 917.0159 3.1606 1.62041 60.34
17 -65.4856 0.1500
18 81.4594 5.1676 1.49700 81.61
19 -50.2651 1.0000 1.91082 35.25
20 12857.9429 0.1500
21 39.7020 3.7454 1.64769 33.84
22 165.3683 3.3038
23 52.9808 1.9000 1.88100 40.14
24 33.0522 5.4858
25 (Aperture) ∞ (d25)
26 294.0289 4.2603 1.69680 55.46
27 -35.1097 1.0000 1.95375 32.32
28 -80.1614 0.1500
29 78.1387 2.5322 1.59349 67.00
30 -377.4708 (d30)
31 87.7761 1.0000 1.80420 46.50
32 26.8830 2.2144 1.72825 28.32
33 36.6224 21.2579
34 -101.5049 2.0000 1.43700 95.10
35 37.2848 4.1070 1.60342 38.01
36 203.2256 (BF)
Image plane ∞

[Various data]
Zoom ratio 3.74
Wide angle Medium telephoto
Focal length 154.77 270.00 578.86
F number 5.06 5.84 6.49
Full angle of view 2ω 15.71 9.03 4.21
Image height Y 21.63 21.63 21.63
Total lens length 298.7481 340.7869 379.0428

[Variable interval data]
Wide angle Medium telephoto
d5 46.0134 88.0521 126.3078
d15 29.1520 23.7340 3.5000
d25 32.6154 19.6895 25.1890
d30 17.4253 10.1944 1.9975
BF 45.1711 70.7460 93.6776

[Lens group data]
Group Start surface Focal length
G1 1 257.14
G2 6 -46.18
G3 16 77.20
G4 26 62.34
G5 31 -59.18
G2a 6 -277.76
G2b 11 -50.55
G5a 31 -75.35
G5b 34 -357.07

Example 7
Unit: mm
[Surface data]
Surface number rd nd vd
1 370.6330 3.0000 1.83481 42.72
2 127.6111 10.3116 1.49700 81.61
3 -1345.5535 0.1500
4 127.2682 9.6767 1.49700 81.61
5 ∞ (d5)
6 145.7558 2.9973 1.71736 29.50
7 723.8084 22.5896
8 140.5816 3.0595 1.51742 52.15
9 -140.5816 1.0000 1.88300 40.80
10 91.5361 6.1057
11 -300.0543 0.7000 1.69680 55.46
12 88.4743 2.7214
13 -64.5061 0.7000 1.69680 55.46
14 66.6869 2.7410 1.80518 25.46
15 6186.2394 (d15)
16 1220.3717 3.1551 1.62041 60.34
17 -64.6325 0.1500
18 82.7645 5.1690 1.49700 81.61
19 -49.8333 1.0000 1.91082 35.25
20 -4479.2347 0.1500
21 39.6642 3.7281 1.64769 33.84
22 159.7630 3.4204
23 52.6520 1.9000 1.88100 40.14
24 32.9896 5.4905
25 (Aperture) ∞ (d25)
26 285.4516 4.2383 1.69680 55.46
27 -35.2509 1.0000 1.95375 32.32
28 -81.6685 0.1500
29 80.1273 2.5468 1.59349 67.00
30 -304.8572 (d30)
31 88.3160 1.0000 1.80420 46.50
32 27.2454 2.1595 1.75520 27.53
33 36.0764 (d33)
34 -96.6261 1.9935 1.43700 95.10
35 38.1247 4.1376 1.60342 38.01
36 223.3526 (BF)
Image plane ∞

[Various data]
Zoom ratio 3.74
Wide angle Medium telephoto
Focal length 154.77 269.96 578.86
F number 5.10 5.84 6.51
Full angle of view 2ω 15.71 9.03 4.21
Image height Y 21.63 21.63 21.63
Total lens length 298.8477 341.1342 379.1761

[Variable interval data]
Wide angle Medium telephoto
d5 46.2834 88.5697 126.6121
d15 29.7073 23.7653 3.5000
d25 31.4942 20.0095 25.3557
d30 16.6915 10.2099 1.9971
d33 22.6552 20.3464 21.2514
BF 44.8745 71.0918 93.3182

[Lens group data]
Group Start surface Focal length
G1 1 257.40
G2 6 -46.22
G3 16 77.13
G4 26 62.12
G5 31 -75.06
G6 33 -350.93
G2a 6 -278.80
G2b 11 -50.58

Example 8
Unit: mm
[Surface data]
Surface number rd nd vd
1 550.2301 3.0000 1.83481 42.72
2 144.9435 10.6178 1.49700 81.61
3 -508.0778 0.1500
4 133.4833 9.2990 1.49700 81.61
5 ∞ (d5)
6 148.9001 2.9142 1.71736 29.50
7 700.0000 22.4340
8 159.6819 2.8639 1.51742 52.15
9 -159.6819 1.0000 1.88300 40.80
10 91.2597 6.1064
11 -214.1812 0.7000 1.69680 55.46
12 94.8167 2.8442
13 -57.6477 0.7000 1.69680 55.46
14 76.1754 2.8444 1.80518 25.46
15 -392.6584 (d15)
16 235.0685 3.5316 1.69680 55.46
17 -66.2550 0.1500
18 70.0938 5.2152 1.49700 81.61
19 -53.3381 1.0000 1.90043 37.37
20 296.4532 0.1500
21 34.3415 5.7678 1.58144 40.89
22 89.1967 2.6246
23 46.2929 1.9000 1.88100 40.14
24 30.4491 5.4557
25 (Aperture) ∞ (d25)
26 154.5168 4.0267 1.65844 50.85
27 -36.8251 1.0000 1.95375 32.32
28 -82.3995 0.1500
29 63.3772 2.2199 1.58913 61.25
30 373.4005 (d30)
31 64.6555 1.0000 1.91082 35.25
32 29.1373 8.8009
33 -73.8858 1.0000 1.43700 95.10
34 31.7813 4.5840 1.64769 33.84
35 -1000.0000 (BF)
Image plane ∞

[Various data]
Zoom ratio 3.74
Wide angle Medium telephoto
Focal length 154.67 270.01 578.85
F number 5.14 5.75 6.50
Full angle of view 2ω 15.58 8.95 4.19
Image height Y 21.63 21.63 21.63
Total lens length 298.9154 344.1588 379.0824

[Variable interval data]
Wide angle Medium telephoto
d5 47.8096 93.0528 127.9769
d15 30.3675 25.8998 3.5000
d25 34.5016 19.2696 25.0138
d30 18.0578 9.2937 1.9973
BF 54.1286 82.5926 106.5441

[Lens group data]
Group Start surface Focal length
G1 1 255.82
G2 6 -45.90
G3 16 69.85
G4 26 64.59
G5 31 -65.63
G2a 6 -254.33
G2b 11 -51.56

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8
Condition 1 0.814 0.781 0.732 0.790 0.785 0.778 0.779 0.776
Conditional expression 2 -0.0144 -0.0153 -0.0190 -0.0161 -0.0166 -0.0170 -0.0169 -0.0150

In the imaging optical system of the present invention, it is more effective to have the following configuration.

More preferably, the rear lens group includes a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a negative refractive power in order from the object side.

However, the present invention does not exclude configurations other than the above five-group configuration. Naturally, a configuration in which a reduction optical system or a multiplication optical system in which various aberrations are sufficiently corrected is added after the fifth lens group is also included. Of course, a system in which a demagnification optical system or a multiplication optical system is added to the optical system of the present invention including the first lens group to the fifth lens group includes the first lens group to the fifth lens group of the present invention. This system has the characteristics of the optical system. The optical system is not essentially changed before and after the addition of the demagnification optical system or the multiplication optical system.

It is more desirable that the 2a group includes a positive lens and a cemented lens including a positive lens and a negative lens in order from the object side.

The 2b group is more preferably composed of three or less lenses including one positive lens. When the number is four or more, it is difficult to suppress the weight of the vibration isolation group.

In addition, in order to correct the chromatic aberration of the 2b group and suppress the occurrence of lateral chromatic aberration during image stabilization, it is desirable to have at least one positive lens in the 2b group.

In addition, it is desirable to have two negative lenses in the 2b group in order to suppress the occurrence of spherical aberration, coma and the like while maintaining the negative refractive power of the 2b group sufficiently.

G1 1st lens group G2 2nd lens group G2a 2a group (2nd lens group front group)
G2b 2b group (second lens group rear group)
Gr Rear lens group G3 Third lens group G4 Fourth lens group G5 Fifth lens group G5a 5a group (Fifth lens group front group)
G5b 5b group (5th lens group rear group)
G6 6th lens group S Aperture stop I Image surface

Claims (4)

From the object side,
A first lens unit having a positive refractive power;
A second lens unit having negative refractive power;
Consists of a rear lens group with positive refractive power as a whole in the entire zoom range,
Each lens group is separated by an air interval, and the air interval between each lens group changes at the time of zooming,
The rear lens group is composed of at least two lens groups that move in independent orbits during zooming,
The second lens group is composed of a negative refractive power 2a group and a negative refractive power 2b group in order from the object side, and performs vibration isolation by displacing the 2b group in a direction perpendicular to the optical axis.
The group 2a has a lens component having a positive refractive power closest to the object side,
A variable magnification imaging optical system having an anti-vibration function characterized by satisfying the following conditional expression:
(1) 0.70 <| LT2a / f2a | <0.85
(2) −0.025 <dpp2a / | f2a | <−0.005
However,
LT2a is the distance from the most object side surface of 2a group to the image side focal point of 2a group,
f2a is the focal length of the group 2a,
dpp2a is the distance from the object side principal point of the group 2a to the image side principal point,
It is.   2. A variable magnification imaging optical system having an anti-vibration function according to claim 1, wherein the second lens group is fixed with respect to the image plane at the time of zooming.   3. The variable magnification imaging optical system with an image stabilization function according to claim 1, wherein the rear lens group includes a third lens group having a positive refractive power closest to the object side.   The rear lens group has a lens unit having a negative refractive power closest to the image side, and when focusing, all or a part of any one of the rear lens groups excluding the third lens group is moved. A variable magnification imaging optical system having the image stabilization function according to claim 3.

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