JP2016080825A - 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, at least a first lens group having positive refractive power, second lens group having negative refractive power, third lens group having positive refractive power, fourth lens group having positive refractive power, and fifth lens group having negative refractive power, where each lens group is separated from the one next thereto by an air gap that changes while zooming. Some lenses of the second group are moved in a direction perpendicular to an optical axis for anti-shake correction. The zoom imaging optical system simultaneously satisfies conditional expressions below.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.

Anti-vibration functions are being installed in imaging optical systems used in digital still cameras, etc., and failure due to camera shake has decreased even in photography using super-telephoto lenses, making super-telephoto lenses familiar. Yes. For this reason, an imaging optical system having a longer focal length and a narrow angle of view has been demanded.

An imaging optical system in which the angle of view at the telephoto end corresponds to a focal length of 500 mm to 600 mm in terms of a focal length of 500 mm to 600 mm in terms of a 35 mm size is 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 optical total length 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. It is effective to adopt a refractive power arrangement called “.

In a long focal length imaging optical system, the lens element tends to have a large diameter, especially on the object side, and the amount of movement of each group including the first lens group increases with zooming. The power required for zooming operation tends to increase. In order to make the zooming operation smooth and easy to use, it is necessary to suppress the movement amount of each group. However, since it is necessary to make each group refractive power larger than the refractive power at the telephoto end of the entire zooming optical system, it is difficult to correct various aberrations including spherical aberration. In particular, fluctuations in coma due to decentering due to manufacturing errors of the lens group behind the optical system tend to increase, and the expected value of imaging performance after manufacturing tends to decrease.

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 also tends to increase in weight and displacement in the long-focus 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. Further, 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. In addition, coma variation due to the tilt of the third lens group is large, and dissatisfaction remains with the expected performance value after manufacturing. Furthermore, since the beam 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, the telephoto ratio cuts 0.65, and the total optical length is very short, but no mention is made of vibration isolation.

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 although the anti-vibration group has one structure, weight reduction is not possible. It is enough. Further, the coma aberration variation accompanying the tilt and shift of the second, third, and fourth lens groups is large, and dissatisfaction remains with the expected performance value after manufacturing.

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. Furthermore, the coma aberration variation due to the tilt of the third lens group and the fourth lens group is large, and dissatisfaction remains with the expected performance value after manufacturing.

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;
A third lens group having a positive refractive power;
A fourth lens unit having a positive refractive power;
At least a fifth lens unit having a negative refractive power;
Each lens group is separated by an air interval, and the air interval between each lens group changes at the time of zooming,
Vibration is prevented by displacing a part of the second lens group in a direction perpendicular to the optical axis,
A variable magnification imaging optical system having an anti-vibration function characterized in that the following conditional expressions (1), (2) and (3) are satisfied simultaneously.
(1) F3 = | (β3 * H3-H3 ′) / ((1-β3) * f3 + H3 ′) | <0.25
(2) F4 = | (β4 * H4-H4 ′) / ((1−β4) * f4 + H4 ′) | <0.25
(3) √ (F3 ^ 2 + F4 ^ 2) / 2 <0.15
However,
βi is the imaging magnification at the telephoto end of the i-th lens group, Hi is the distance from the most object-side interface of the i-th lens group to the object-side principal point of the i-th lens group,
Hi ′ is the distance fi from the most image-side interface of the i-th lens group to the image-side principal point of the i-th lens group, the combined focal length F3 of the i-th lens group is the incident height of the paraxial peripheral ray of the third lens group Is the ratio of the incident height of the paraxial peripheral ray of the fourth lens unit to the exit height.

In the invention according to claim 2, 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 the 2b group is displaced in a direction perpendicular to the optical axis. 2. The variable magnification imaging optical system having the image stabilization function according to claim 1, wherein image stabilization is performed.

According to a third aspect of the present invention, there is provided a variable magnification imaging optical system having the image stabilization function according to the second aspect, wherein the following conditional expression (4) is satisfied.
(4) 0.70 <| LT2a / f2a | <0.85
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 group 2a

The invention according to claim 4 is characterized in that the second lens group is fixed with respect to the image plane at the time of zooming. An image optical system was obtained.

The invention according to claim 5 has a lens unit having a negative refractive power on the most image side of the optical system, and moves all or a part of any of the lens units after the fourth lens unit during focusing. 5. A variable magnification imaging optical system having an image stabilization function according to claim 1, wherein

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 high-performance variable magnification imaging optical system having an image stabilization 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. 10 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 has an object side as shown in the lens configuration diagrams shown in FIGS. 1, 11, 21, 31, 41, 51, 61, and 71. A first lens group having a positive refractive index, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a fifth lens having a negative refractive power in order from A lens group is provided. The lens groups are separated from each other by an air interval, and zooming is performed by changing the air interval between the lens groups.

The variable magnification imaging optical system having an image stabilization function according to the present invention includes a first lens unit having a positive refractive power and a negative refraction in order from the object side in order to suppress the total length while increasing the focal length at the telephoto end. A telephoto-type refracting power arrangement is configured by arranging a second lens group of force.

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.

The third and subsequent lens groups have a positive refractive power as a whole, and move toward the object side as a whole and move closer to the second lens group with zooming from the wide-angle end to the telephoto end. Bear. At the same time, the refractive power of the synthesis system after the second lens group changes in the negative direction, so that the telephoto refractive power arrangement formed by the synthesis system of the first lens group, the second lens group, and the third lens group is wide angle. It becomes stronger from the end toward the telephoto end. Due to the action of each group from the first lens group to the third lens group, the optical total length is relatively long with respect to the total focal length of the entire system at the wide angle end, and the optical total length with respect to the total focal length of the entire system at the telephoto end. Becomes relatively short, and the amount of movement of the first lens group 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. By using only a part of the second lens group as the anti-vibration group, it is possible to further reduce the weight of the anti-vibration group compared to using the entire second lens group as the anti-vibration group.

The third lens group emits the light beam diverged by the second lens group in a state close to afocal and is further converged by the fourth lens group. When the distance between the third lens group and the fourth lens group changes, the light beam between them is almost afocal, so the axial spherical aberration does not change substantially. However, the height of the off-axis light beam changes and astigmatism does not occur. Change. Astigmatism can be satisfactorily corrected over the entire zooming range by appropriately setting the distance between the third lens unit and the fourth lens unit with zooming.

Further, the fifth lens unit having a negative refractive power is provided on the object side, and the refractive power arrangement of the composite system from the third lens unit to the fifth lens unit is made telephoto, which is advantageous for shortening the total optical length of the entire system. is there. Increasing the imaging magnification of the fifth lens group by moving the fifth lens group to the object side so that the distance between the fourth lens group and the fifth lens group becomes narrow when zooming from the wide-angle end to the telephoto end. This contributes to zooming, and thus contributes to a reduction in the amount of movement of the first lens group.

Since the third lens group and the fourth lens group need to converge the light beam diverged by the second lens group, a large refractive power is required, and correction of spherical aberration by the third lens group and the fourth lens group alone is performed. Tend to be difficult. Further, since the magnification of the fifth lens group is large, the aberration variation caused by the third lens group and the fourth lens group is enlarged and formed on the image plane. For this reason, especially the coma aberration fluctuation tends to become large due to the decentering of the third lens group and the fourth lens group.

In order to reduce the variation of coma aberration caused by the eccentricity of the third lens group and the fourth lens group, it is effective to suppress the occurrence of spherical aberration inside the third lens group and the fourth lens group. For this purpose, it is preferable that the change in the passing height of the paraxial peripheral ray before and after passing through the third lens group and the fourth lens group is suppressed.

Hereinafter, the passing height of the paraxial peripheral ray on the front and rear surfaces of the thick lens system will be described.

The composite focal length of the thick lens system is f, the imaging magnification is β, the distance from the most object side interface of the thick lens system to the object side principal point is H, and the image is from the most image side interface of the thick lens system. The distance to the side principal point is H ′, the angle formed by the paraxial peripheral ray incident on the thick lens system with the optical axis is θ, and the angle formed by the paraxial peripheral ray emitted from the thick lens system with the optical axis is θ 'And.

At this time, because of Newton's imaging formula and paraxial rays, the paraxial marginal ray incidence height h to the thick lens system and the paraxial marginal ray exit height h ′ from the thick lens system are as follows: It can be expressed by an expression.
h = ((1-1 / β) * f−H) * θ
h ′ = ((1−β) * f + H ′) * θ ′
Furthermore, since β = −θ / θ ′, to summarize, the ratio between the paraxial peripheral ray incident height h and the paraxial peripheral ray exit height h ′ is expressed by the following equation.
h / h ′ = 1 + (βH−H ′) / ((1−β) * f + H ′)

Conditional expressions (1) and (2) define the condition of the ratio between the incident height and the exit height of the paraxial peripheral ray in the third lens group and the fourth lens group.

Conditional expression (3) is a mean square value of the values of conditional expression (1) and conditional expression (2). The smaller the value, the smaller the values of conditional expressions (1) and (2) on average. Correspondingly, it means that the fluctuation of the paraxial marginal ray height in the third lens group and the fourth lens group is small.

When the upper limit of conditional expressions (1) to (2) is exceeded and the variation in the paraxial marginal ray passing height in the third lens group to the fourth lens group becomes large, the occurrence of spherical aberration in the third lens group. As a result, the fluctuation of the coma aberration when the third lens group is decentered cannot be suppressed. Further, when the upper limit of the conditional expression (3) is exceeded and the variation of the paraxial peripheral ray height as the whole of the third lens group and the fourth lens group becomes large, it is within the range of the conditional expressions (1) to (2). In the case where the decentering of the third lens group and the fourth lens group occurs simultaneously in the opposite directions, fluctuations in coma aberration cannot be ignored.

By setting the upper limit of conditional expression (1) to conditional expression (2) to 0.23 and further to 0.20, the effect of the present invention can be achieved more reliably. Moreover, the effect of this invention can be achieved more reliably by making the upper limit of conditional expression (3) into 0.14, and also 0.13.

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, which is suitable for further weight reduction of the image stabilization group. .

Conditional expression (4) 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 (4) is exceeded and the telephoto ratio of the group 2a is increased, the total length is shortened and the light beam diameter is not sufficiently suppressed. If the lower limit of conditional expression (4) is exceeded and the telephoto ratio of the group 2a is reduced, the effect of shortening the total length and suppressing the beam diameter is enhanced, 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 (4) is set to 0.83, further to 0.82, and the lower limit of conditional expression (4) is set to 0.71 and further to 0.72, thereby achieving the effect of the present invention more reliably. can do.

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. Since the second lens group includes the image stabilizing group, it is necessary to connect the control wiring. When the second lens group moves, it is connected by flexible wiring, and in order not to apply excessive stress to the flexible wiring as the second lens group moves, a space for deflecting and retracting the flexible wiring is required. Become. Therefore, it is difficult to reduce the size of the entire lens barrel because it is necessary to secure the space.

In the variable magnification imaging optical system having the image stabilization function of the present invention, the lens unit having the negative refractive power on the most image side, and the entire lens unit after the fourth lens unit during focusing, or It is desirable to move a part. 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-focus optical system, the outer diameter is too large at the portion close to the object side, 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. In the rear lens group, if the lens group is further rearward than the third 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 lens group after the fourth 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 having negative refractive power, and when zooming from the wide-angle end state to the telephoto end state, the first lens group moves to the object side, the second lens group is fixed, and the third lens group Moves to the object side, the fourth lens group moves to the object side, and the fifth lens group moves to the object side.

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 having negative refractive power, and when zooming from the wide-angle end state to the telephoto end state, the first lens group moves to the object side, the second lens group is fixed, and the third lens group Moves to the object side, the fourth lens group moves to the object side, and the fifth lens group moves to the object side.

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 having negative refractive power, and when zooming from the wide-angle end state to the telephoto end state, the first lens group moves to the object side, the second lens group is fixed, and the third lens group Moves to the object side, the fourth lens group moves to the object side, and the fifth lens group moves to the object side.

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 having negative refractive power, and when zooming from the wide-angle end state to the telephoto end state, the first lens group moves to the object side, the second lens group is fixed, and the third lens group Moves to the object side, the fourth lens group moves to the object side, and the fifth lens group moves to the object side.

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 having negative refractive power, and when zooming from the wide-angle end state to the telephoto end state, the first lens group moves to the object side, the second lens group is fixed, and the third lens group Moves to the object side, the fourth lens group moves to the object side, and the fifth lens group moves to the object side.

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 having negative refractive power, and when zooming from the wide-angle end state to the telephoto end state, the first lens group moves to the object side, the second lens group is fixed, and the third lens group Moves to the object side, the fourth lens group moves to the object side, and the fifth lens group moves to the object side.

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 5a 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. Upon zooming from the wide-angle end state to the telephoto end state, the first lens group moves to the object side, The second lens group is fixed, the third lens group moves to the object side, the fourth lens group moves to the object side, the fifth lens group moves to the object side, and the sixth lens group moves to the object side. It has a configuration.

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 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 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 having negative refractive power, and when zooming from the wide-angle end state to the telephoto end state, the first lens group moves to the object side, the second lens group is fixed, and the third lens group Moves to the object side, the fourth lens group moves to the object side, the fifth lens group moves to the object side, and the sixth lens group moves to the object side.

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

Numerical 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

Numerical 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

Numerical 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

Numerical 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

Numerical 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

Numerical 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

Conditional expression correspondence table
Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8
Conditional expression 1 0.1490 0.1627 0.1501 0.1461 0.1323 0.1257 0.1264 0.1879
Conditional expression 2 0.0688 0.0629 0.0691 0.0598 0.0581 0.0500 0.0499 0.0639
Conditional expression 3 0.0821 0.0872 0.0826 0.0789 0.0722 0.0676 0.0680 0.0993
Conditional expression 4 0.8143 0.7809 0.7317 0.7895 0.7851 0.7780 0.7788 0.7765

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

More preferably, the third lens group includes two or more positive lenses, one of which is a cemented lens with a negative lens, and its cemented surface has a diverging action. Since the light beam diverged in the second group is incident on the third lens group, and the entire optical system needs to converge the light beam, the third lens group needs to have a strong light beam converging action. In order to have a strong convergence effect while suppressing the occurrence of spherical aberration, it is desirable to divide the refractive power into two or more positive lenses. Further, one of them is cemented with a negative lens, and spherical aberration can be corrected by making the cemented surface a divergent surface.

The most object side and most image side lenses of the fourth lens group are preferably positive lenses. By bringing the refractive power arrangement in the fourth lens group close to symmetry, the paraxial marginal ray incident height and paraxial marginal ray exit height to the fourth lens group become close, and coma aberration associated with the tilt of the entire fourth lens group. Fluctuations can be reduced.

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. This is because when the number of sheets 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.

The present invention does not exclude configurations other than the five-group configuration as described above. 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.

G1 1st lens group G2 2nd lens group G2a 2a group (2nd lens group front group)
G2b 2b group (second lens group rear group)
G3 3rd lens group G4 4th lens group G5 5th lens group G5a 5a group (5th lens group front group)
G5b 5b group (the rear group of the fifth lens group)
G6 6th lens group S Aperture stop I Image surface

Claims (5)

From the object side,
A first lens unit having a positive refractive power;
A second lens unit having negative refractive power;
A third lens group having a positive refractive power;
A fourth lens unit having a positive refractive power;
At least a fifth lens unit having a negative refractive power;
Each lens group is separated by an air interval, and the air interval between each lens group changes at the time of zooming,
Vibration is prevented by displacing a part of the second lens group in a direction perpendicular to the optical axis,
A variable magnification imaging optical system having an anti-vibration function characterized by simultaneously satisfying the following conditional expressions:
F3 = | (β3 * H3-H3 ′) / ((1−β3) * f3 + H3 ′) | <0.25
F4 = | (β4 * H4-H4 ′) / ((1-β4) * f4 + H4 ′) | <0.25
√ (F3 ^ 2 + F4 ^ 2) / 2 <0.15
However,
βi is the imaging magnification Hi at the telephoto end of the i-th lens group, Hi is the distance Hi ′ from the most object-side interface of the i-th lens group to the object-side principal point of the i-th lens group, and is the most image side of the i-th lens group The distance fi from the interface to the image side principal point of the i-th lens group is the combined focal length F3 of the i-th lens group, and the ratio F4 of the incident height and the exit height of the paraxial peripheral ray of the third lens group is the fourth lens group. The ratio between the incident height and the exit height of the paraxial peripheral ray. 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 is characterized in that vibration is prevented by displacing the 2b group in a direction perpendicular to the optical axis. A variable magnification imaging optical system having the image stabilization function according to claim 1. The variable magnification imaging optical system having an image stabilization function according to claim 2, wherein the following expression is satisfied.
0.70 <| LT2a / f2a | <0.85
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,
It is. 4. A 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 during zooming. 2. A lens unit having a negative refractive power closest to the image side of the optical system, and the whole or a part of any one of the fourth lens unit and the subsequent lens units is moved during focusing. 5. A variable magnification imaging optical system having the image stabilization function described in 4.

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