JP5714535B2 - Imaging optical system with anti-vibration mechanism - Google Patents

Description

  The present invention relates to an imaging optical system provided with an image stabilization mechanism suitable for a photographing lens used in a digital camera, a video camera, or the like.

  In recent years, with the widespread use of imaging devices such as digital still cameras and video cameras, the number of pixels of the image sensor has been rapidly increasing, and an image-forming optical system with higher image quality has been demanded. Further, in recent years, an increasing number of cameras employ a large image sensor in order to obtain high image quality.

  If the number of pixels is the same, a large image sensor has a larger area per pixel than a small image sensor, so that a good image with less noise can be obtained. However, as the image pickup device becomes larger, the imaging optical system tends to increase in size.

  An image sensor widely used in an image pickup apparatus generally has a characteristic that sensitivity decreases with respect to light having a large incident angle. In order to keep the incident angle small to the periphery of the image sensor, a retrofocus type refractive power arrangement is advantageous.

  However, the retrofocus type refractive power arrangement tends to increase the total length of the imaging optical system with respect to the size of the image sensor. In an image pickup apparatus using a large image pickup element, the entire image pickup apparatus is increased in size when the overall length of the imaging optical system is increased.

  Therefore, an optical system corresponding to a large image sensor has to be miniaturized as much as possible while suppressing an incident angle to the image sensor, that is, a light emission angle from the imaging optical system.

  For example, Patent Documents 1 to 3 disclose a compact imaging optical system having an angle of view of about 50 to 60 ° to deal with a large image sensor.

JP 2003-241084 A

JP 2009-258158 A

JP 2010-101979 A

  As described above, sufficient miniaturization is an issue in imaging optical systems that support large image sensors, but at the same time minimizing performance degradation and increased sensitivity to manufacturing errors associated with miniaturization. Necessary. In addition, it is desirable to make the lens group used for focusing as light as possible, to reduce the size of the actuator and to increase the focusing speed.

  In addition, in an image sensor with a large number of pixels, it is desirable to mount an anti-vibration mechanism because a slight blur leads to a reduction in image sharpness.

  In the imaging optical system described in Patent Literature 1 and Patent Literature 2, a negative lens and a positive lens are arranged in order from the object side in the first lens group on the object side of the stop, and these lenses are arranged close to each other. By making the combined refractive power positive, and by making the second lens group on the image side from the stop more positive refractive power than the first lens group on the object side, downsizing of the total length and suppression of the light emission angle are achieved. Yes. Focusing can be achieved by using only the second lens unit having a positive refractive power composed of about three lenses, and a certain weight reduction can be achieved. Further, focusing can be speeded up and the actuator can be downsized.

  In the imaging optical systems described in Patent Document 1 and Patent Document 2, in the first lens group closer to the object than the stop, the most object-side surface is convex on the object side, and the most image-side surface is on the image side. Conversely, in the second lens group on the image side relative to the stop, the most object side surface is concave on the object side and the most image side surface is convex on the image side.

  In general, by using a concentric lens shape with respect to the stop as described above, it is possible to reduce the incidence angle of the off-axis principal ray on each surface and suppress the generation of astigmatism and coma on each surface. Further, when the refractive power arrangement of the lens is close to symmetry with the aperture stop as the center, coma aberration, distortion, lateral chromatic aberration, etc. cancel each other between the first lens group and the second lens group, and the entire imaging optical system has good aberration. Correction can be realized.

  However, in such an imaging optical system composed of only the first lens group and the second lens group, the refractive power arrangement changes greatly by moving the second lens group during focusing, and various aberrations, in particular, Since coma aberration, distortion, and lateral chromatic aberration fluctuate, performance at short distances becomes insufficient.

  In addition, since these aberrations increase as the angle of view increases, it is difficult to correct and suppress fluctuations. For this reason, this type of imaging optical system is mainly used in a medium telephoto field angle with a diagonal total field angle of about 30 °, and an example in which it is used for a standard field angle with a diagonal total field angle of about 50 ° is as follows. Few.

  In addition, Patent Document 2 proposes that image stabilization be performed by moving one lens in the focus group in a direction orthogonal to the optical axis. However, since the sensitivity to aberration fluctuation is high, sufficient performance is achieved. Difficult to achieve. Furthermore, the mechanism of the focus group becomes complicated, leading to an increase in the weight of the focus group.

  On the other hand, the imaging optical system described in Patent Document 3 has a retrofocus type refractive power arrangement in which a negative lens element is arranged on the most object side of the optical system, and suppresses a light emission angle. Further, since focusing is performed with one lens closest to the image side, it is very lightweight.

  On the other hand, there is a drawback that the total length is slightly longer due to the retrofocus type refractive power arrangement. In this optical system, the total refractive power is shortened by making the combined refractive power of the group closer to the object side than the stop positive. It is difficult to shorten the overall length due to the strong retrofocus type refractive power arrangement.

  In addition, since the focus group is one on the most image side of the lens system, if the refracting power is increased to reduce the amount of movement, it is difficult to correct the aberration in the focus group alone, and the aberration fluctuations due to focusing are changed. When the refractive power of the focus group is weakened, the amount of movement of the focus group becomes large, which is disadvantageous for downsizing the entire imaging optical system.

  There is no mention of anti-vibration.

  The present invention has been made in view of such a situation, and is suitable for a wide-angle to medium-telephoto field-of-view region in which a diagonal total field angle is approximately 60 ° to 30 °, and is compatible with a large image sensor. To provide an imaging optical system equipped with an anti-vibration mechanism that achieves miniaturization and miniaturization, suppresses the light emission angle, and performs focusing with a lightweight lens group while reducing aberration fluctuations throughout the entire imaging area. Objective.

In order to achieve the above object, an image forming optical system having the first image stabilization mechanism of the present invention includes, in order from the object side, a first lens unit having a positive refractive power, an aperture stop, and a positive refractive power. The second lens group and a third lens group having a negative refractive power, and the second lens group moves toward the object side along the optical axis during focusing from infinity to a short distance, and the third lens group Is composed of a negative refractive power 3a group and a positive refractive power 3b group in order from the object side, the 3a group is composed of one negative lens, and the 3b group has a positive lens closest to the image side, Vibration is prevented by moving the group 3a in a direction perpendicular to the optical axis, and the following conditional expression is satisfied.
(1) 1.20 <f1 / f23 <7.50
(2) 0.01 <| f2 / f3 | <0.35
(3) 0.90 <| f3a × f3b / f ^ 2 | <6.50
However,
fi: focal length of the i-th lens group f23: combined focal length f3a: focal length of the 3a group when the second lens group and the third lens group are focused at infinity f3b: focal length of the 3b group f: imaging optical system Focal length when focusing on infinity of the entire system

The imaging optical system provided with the second image stabilization mechanism according to the present invention is the imaging optical system provided with the first image stabilization mechanism according to the present invention, wherein the first lens group is arranged in order from the object side to the object side. The second lens group includes a negative lens having a concave surface facing the object side and an image side facing the image side in order from the object side. It is composed of a cemented lens DB2 with a positive lens having a convex surface and a biconvex positive lens, and satisfies the following conditional expression.
(4) | RDB1 / f |> 1.00
(5) | RDB2 / f |> 0.85
However,
RDB1: radius of curvature of the cemented surface of the cemented lens DB1 RDB2: radius of curvature of the cemented surface of the cemented lens DB2

  The imaging optical system having the third image stabilization mechanism of the present invention is the imaging optical system having the second image stabilization mechanism of the present invention, and the cemented lens DB1 is included in the first lens group. It is characterized in that it is located closest to the image side among the cemented lenses.

Furthermore, the imaging optical system provided with the fourth image stabilization mechanism of the present invention satisfies the following conditional expression in the imaging optical system provided with any one of the first to third image stabilization mechanisms of the present invention. It is characterized by.
(6) 0.800 <n3a / n3b <0.990
However,
n3a: Maximum value of the refractive index of the negative lens constituting the 3a group n3b: Minimum value of the refractive index of the positive lens constituting the 3b group

Further fifth imaging optical system having a vibration reduction mechanism of the present invention, in the first imaging optical system having a vibration reduction mechanism of the present invention, the second lens group comprises, in order from the object side, the object It is characterized by comprising only a cemented lens DB2 of a negative lens having a concave surface on the side and a positive lens having a convex surface on the image side, and a biconvex positive lens.

  According to the imaging optical system equipped with the image stabilization mechanism embodying the present invention, the diagonal total field angle is suitable for a wide-angle to medium-telephoto field angle range of approximately 60 ° to 30 °, and corresponds to a large image sensor. An imaging optical system that achieves high performance and miniaturization, suppresses the light emission angle, and performs focusing with a lightweight lens group while providing an anti-vibration mechanism with little aberration variation in the entire imaging area be able to.

It is a lens block diagram concerning Example 1 of an image formation optical system provided with the vibration proof mechanism of the present invention. FIG. 6 is a longitudinal aberration diagram at an imaging distance of infinity of the imaging optical system including the image stabilization mechanism of Example 1. FIG. 6 is a longitudinal aberration diagram at an imaging distance of 500 mm of the imaging optical system including the image stabilization mechanism of Example 1. 6 is a lateral aberration diagram at an imaging distance of infinity of an imaging optical system including the image stabilization mechanism of Example 1. FIG. FIG. 6 is a lateral aberration diagram at an imaging distance of 500 mm of the imaging optical system including the image stabilization mechanism of Example 1. FIG. 6 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of infinity of the imaging optical system including the image stabilization mechanism of Example 1. FIG. 6 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of 500 mm of the imaging optical system including the image stabilization mechanism of Example 1. It is a lens block diagram which concerns on Example 2 of the imaging optical system provided with the anti-vibration mechanism of this invention. FIG. 6 is a longitudinal aberration diagram at an imaging distance infinity of an imaging optical system including the image stabilization mechanism of Example 2. FIG. 6 is a longitudinal aberration diagram at an imaging distance of 500 mm of an imaging optical system including the image stabilization mechanism of Example 2. FIG. 6 is a lateral aberration diagram at an imaging distance infinite of the imaging optical system including the image stabilization mechanism of Example 2. FIG. 6 is a lateral aberration diagram at an imaging distance of 500 mm in an image forming optical system including the image stabilization mechanism according to Example 2. FIG. 11 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of infinity of the imaging optical system including the image stabilization mechanism of Example 2. FIG. 10 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of 500 mm of the imaging optical system including the image stabilization mechanism of Example 2. It is a lens block diagram which concerns on Example 3 of the imaging optical system provided with the vibration isolating mechanism of this invention. FIG. 7 is a longitudinal aberration diagram at an imaging distance infinite of the imaging optical system including the image stabilization mechanism of Example 3. FIG. 6 is a longitudinal aberration diagram at an imaging distance of 500 mm of an imaging optical system including the image stabilization mechanism of Example 3. FIG. 10 is a lateral aberration diagram at an imaging distance infinite for the imaging optical system including the image stabilization mechanism according to Example 3. FIG. 6 is a lateral aberration diagram at an imaging distance of 500 mm in an image forming optical system including the image stabilization mechanism according to Example 3. FIG. 11 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of infinity of the imaging optical system including the image stabilization mechanism of Example 3. FIG. 10 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of 500 mm of the imaging optical system including the image stabilization mechanism of Example 3. It is a lens block diagram which concerns on Example 4 of the imaging optical system provided with the anti-vibration mechanism of this invention. FIG. 10 is a longitudinal aberration diagram at an imaging distance infinite of the imaging optical system including the image stabilization mechanism of Example 4. FIG. 6 is a longitudinal aberration diagram at an imaging distance of 500 mm of an imaging optical system including the image stabilization mechanism of Example 4. FIG. 10 is a lateral aberration diagram at an imaging distance infinite for the imaging optical system including the image stabilization mechanism according to Example 4. FIG. 10 is a lateral aberration diagram at an imaging distance of 500 mm in an imaging optical system provided with the image stabilization mechanism of Example 4. FIG. 11 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of infinity of the imaging optical system including the image stabilization mechanism of Example 4. FIG. 10 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of 500 mm of the imaging optical system including the image stabilization mechanism of Example 4. It is a lens block diagram which concerns on Example 5 of the imaging optical system provided with the anti-vibration mechanism of this invention. FIG. 10 is a longitudinal aberration diagram at an imaging distance infinite of an imaging optical system including the image stabilization mechanism of Example 5. FIG. 9 is a longitudinal aberration diagram at an imaging distance of 500 mm of an imaging optical system provided with the image stabilization mechanism of Example 5. FIG. 10 is a transverse aberration diagram at an imaging distance infinite of the imaging optical system including the image stabilization mechanism of Example 5. FIG. 10 is a lateral aberration diagram at an imaging distance of 500 mm of the imaging optical system including the image stabilization mechanism of Example 5. FIG. 10 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of infinity of the imaging optical system including the image stabilization mechanism of Example 5. FIG. 10 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of 500 mm of the imaging optical system including the image stabilization mechanism of Example 5. It is a lens block diagram which concerns on Example 6 of the imaging optical system provided with the anti-vibration mechanism of this invention. FIG. 10 is a longitudinal aberration diagram at an imaging distance infinite of an imaging optical system provided with the image stabilization mechanism of Example 6. FIG. 12 is a longitudinal aberration diagram at an imaging distance of 500 mm of an imaging optical system provided with the image stabilization mechanism of Example 6. FIG. 10 is a lateral aberration diagram at an imaging distance infinite of the imaging optical system including the image stabilization mechanism according to Example 6. FIG. 10 is a lateral aberration diagram at an imaging distance of 500 mm of an imaging optical system provided with the image stabilization mechanism of Example 6. FIG. 11 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of infinity of the imaging optical system including the image stabilization mechanism of Example 6. FIG. 11 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of 500 mm of the imaging optical system including the image stabilization mechanism of Example 6. It is a lens block diagram which concerns on Example 7 of the imaging optical system provided with the anti-vibration mechanism of this invention. FIG. 11 is a longitudinal aberration diagram at an imaging distance infinite of an imaging optical system provided with the image stabilization mechanism of Example 7. FIG. 11 is a longitudinal aberration diagram at an imaging distance of 500 mm of an imaging optical system provided with the image stabilization mechanism of Example 7. FIG. 11 is a lateral aberration diagram at an imaging distance infinite for the imaging optical system including the image stabilization mechanism according to Example 7. FIG. 10 is a lateral aberration diagram at an imaging distance of 500 mm of an imaging optical system provided with the image stabilization mechanism of Example 7. FIG. 18 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of infinity of the imaging optical system including the image stabilization mechanism of Example 7. FIG. 12 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of 500 mm of the imaging optical system including the image stabilization mechanism of Example 7. It is a lens block diagram which concerns on Example 8 of the imaging optical system provided with the anti-vibration mechanism of this invention. FIG. 12 is a longitudinal aberration diagram at an imaging distance infinite of an imaging optical system including the image stabilization mechanism of Example 8. FIG. 10 is a longitudinal aberration diagram at an imaging distance of 500 mm in an imaging optical system provided with the image stabilization mechanism of Example 8. FIG. 10 is a lateral aberration diagram at an imaging distance infinite of the imaging optical system including the image stabilization mechanism of Example 8. FIG. 10 is a transverse aberration diagram at an imaging distance of 500 mm of an imaging optical system provided with the image stabilization mechanism of Example 8. FIG. 14 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of infinity of the imaging optical system including the image stabilization mechanism of Example 8. FIG. 10 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of 500 mm of the imaging optical system including the image stabilization mechanism of Example 8. It is a lens block diagram which concerns on Example 9 of the imaging optical system provided with the anti-vibration mechanism of this invention. FIG. 12 is a longitudinal aberration diagram at an imaging distance infinite of the imaging optical system including the image stabilization mechanism of Example 9. FIG. 10 is a longitudinal aberration diagram at an imaging distance of 500 mm of an imaging optical system provided with the image stabilization mechanism of Example 9. FIG. 10 is a lateral aberration diagram at an imaging distance infinite of the imaging optical system including the image stabilization mechanism according to Example 9. 10 is a lateral aberration diagram at an imaging distance of 500 mm of an imaging optical system provided with the image stabilization mechanism of Example 9. FIG. FIG. 10 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of infinity of the imaging optical system including the image stabilization mechanism of Example 9. FIG. 10 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of 500 mm of the imaging optical system including the image stabilization mechanism of Example 9. It is a lens block diagram which concerns on Example 10 of the imaging optical system provided with the vibration isolating mechanism of this invention. FIG. 11 is a longitudinal aberration diagram at an imaging distance infinite of the imaging optical system including the image stabilization mechanism of Example 10. FIG. 12 is a longitudinal aberration diagram at an imaging distance of 500 mm of an imaging optical system provided with the image stabilization mechanism of Example 10. FIG. 10 is a transverse aberration diagram at an imaging distance infinite of the imaging optical system including the image stabilization mechanism according to Example 10. FIG. 10 is a lateral aberration diagram at an imaging distance of 500 mm of the imaging optical system including the image stabilization mechanism according to Example 10. FIG. 27 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of infinity of the imaging optical system including the image stabilization mechanism of Example 10. FIG. 25 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of 500 mm of the imaging optical system including the image stabilization mechanism of Example 10. It is a lens block diagram which concerns on Example 11 of the imaging optical system provided with the anti-vibration mechanism of this invention. FIG. 18 is a longitudinal aberration diagram at an imaging distance infinite of the imaging optical system including the image stabilization mechanism of Example 11. FIG. 12 is a longitudinal aberration diagram at an imaging distance of 500 mm of an imaging optical system provided with the image stabilization mechanism of Example 11. FIG. 12 is a lateral aberration diagram at an imaging distance infinite for the imaging optical system including the image stabilization mechanism according to Example 11. 12 is a lateral aberration diagram at an imaging distance of 500 mm of an imaging optical system including the image stabilization mechanism according to Example 11. FIG. FIG. 25 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of infinity of the imaging optical system including the image stabilization mechanism of Example 11. FIG. 25 is a lateral aberration diagram in a state where the image stabilization group is shifted by 0.25 mm in the plus direction at an imaging distance of 500 mm of the imaging optical system including the image stabilization mechanism of Example 11. It is a lens block diagram which concerns on Example 12 of the imaging optical system provided with the anti-vibration mechanism of this invention. FIG. 14 is a longitudinal aberration diagram at an imaging distance infinity of an image forming optical system including the image stabilization mechanism according to Example 12. FIG. 14 is a longitudinal aberration diagram at an imaging distance of 800 mm of an image forming optical system including the image stabilization mechanism according to Example 12. FIG. 16 is a transverse aberration diagram at an imaging distance infinite of the imaging optical system including the image stabilization mechanism according to Example 12. FIG. 18 is a lateral aberration diagram at an imaging distance of 800 mm in the image forming optical system including the image stabilization mechanism according to Example 12. FIG. 25 is a lateral aberration diagram in a state where the image stabilization group is shifted 0.5 mm in the plus direction at an imaging distance of infinity of the imaging optical system including the image stabilization mechanism of Example 12. FIG. 25 is a lateral aberration diagram in a state where the image stabilization group is shifted 0.5 mm in the plus direction at an imaging distance of 800 mm of the imaging optical system including the image stabilization mechanism of Example 12. It is a lens block diagram which concerns on Example 13 of the imaging optical system provided with the anti-vibration mechanism of this invention. FIG. 14 is a longitudinal aberration diagram at an imaging distance infinity of an image forming optical system including the image stabilization mechanism according to Example 13. FIG. 14 is a longitudinal aberration diagram at an imaging distance of 800 mm of an image forming optical system including the image stabilization mechanism according to Example 13. FIG. 25 is a lateral aberration diagram at an imaging distance infinite for the imaging optical system including the image stabilization mechanism according to Example 13; 14 is a lateral aberration diagram at an imaging distance of 800 mm in an image forming optical system including the image stabilization mechanism according to Example 13. FIG. FIG. 25 is a lateral aberration diagram in a state where the image stabilization group is shifted 0.5 mm in the plus direction at an imaging distance of infinity of the imaging optical system including the image stabilization mechanism of Example 13. FIG. 25 is a lateral aberration diagram in a state where the image stabilization group is shifted 0.5 mm in the plus direction at an imaging distance of 800 mm of the imaging optical system including the image stabilization mechanism of Example 13. It is a lens block diagram which concerns on Example 14 of the imaging optical system provided with the anti-vibration mechanism of this invention. FIG. 16 is a longitudinal aberration diagram at an imaging distance infinity of an image forming optical system including the image stabilization mechanism according to Example 14; FIG. 18 is a longitudinal aberration diagram at an imaging distance of 800 mm of an image forming optical system including the image stabilization mechanism according to Example 14. FIG. 25 is a lateral aberration diagram at an imaging distance infinite of the imaging optical system including the image stabilization mechanism according to Example 14; FIG. 25 is a lateral aberration diagram at an imaging distance of 800 mm of the imaging optical system provided with the image stabilization mechanism according to Example 14. FIG. 27 is a lateral aberration diagram in a state where the image stabilization group is shifted 0.5 mm in the plus direction at an imaging distance infinity of the imaging optical system including the image stabilization mechanism according to Example 14; FIG. 25 is a lateral aberration diagram in a state where the image stabilization group is shifted 0.5 mm in the plus direction at an imaging distance of 800 mm of the imaging optical system including the image stabilization mechanism of Example 14. It is a figure explaining the aberration correction at the time of vibration isolation when the refractive power of the vibration isolation group is negative. It is a figure explaining the aberration correction at the time of image stabilization when the refractive power of an image stabilization group is positive.

  The imaging optical system of the present invention is shown in FIGS. 1, 8, 15, 22, 29, 36, 43, 50, 57, 64, 71, 78, 85, and FIG. As can be seen from the lens configuration diagram shown in FIG. 92, in order from the object side, the first lens group G1 having a positive refractive power, the aperture stop S, the second lens group G2 having a positive refractive power, and a negative refractive power. The third lens group G3 is configured such that the second lens group G2 moves to the object side along the optical axis during focusing from infinity to a short distance.

  The third lens group G3 is composed of a negative refractive power 3a group G3a and a positive refractive power 3b group G3b in order from the object side. By moving the 3a group G3a in a direction perpendicular to the optical axis, vibration is prevented. I do.

  First, a qualitative description will be given of aberration fluctuations accompanying focusing in the synthesis system of the first lens group G1 and the second lens group G2.

  In general, the signs of the residual aberrations of the positive refractive power lens group and the negative refractive power lens group on the same side with respect to the aperture stop are opposite. Further, the occurrence of off-axis aberrations such as coma aberration increases as the off-axis principal ray passage position is farther from the optical axis.

  In the imaging optical system provided with the image stabilization mechanism of the present invention, the off-axis principal ray passing position in the first lens group G1 hardly changes with focusing from infinity to a short distance, but the second lens group G2 Since it moves to the object side, the off-axis principal ray passing position in the second lens group G2 becomes closer to the optical axis.

  For this reason, although the aberration generated by the first lens group G1 hardly changes, the aberration generated by the second lens group becomes small, and aberration fluctuation occurs in the combined system of the first lens group G1 and the second lens group G2. Will occur.

  If the aberration can be sufficiently corrected in each of the first lens group G1 and the second lens group G2, the variation in aberration will be reduced. For this purpose, it is necessary to increase the number of components in each group, and the focus One of the objects of the present invention, the weight reduction of the group, cannot be achieved.

  Therefore, in the imaging optical system equipped with the image stabilization mechanism of the present invention, the third lens group G3 having a negative refractive power that does not move during focusing to the image side of the second lens group G2 is used in order to suppress aberration fluctuations caused by focusing. Introduced. The effect of introducing the third lens group G3 will be described.

  As the second lens group G2 having a positive refractive power approaches the aperture stop S during focusing from infinity to a short distance, the exit pupil moves to the image side, and the off-axis principal ray passing position after the second lens group G2. Is close to the optical axis. Accordingly, the off-axis principal ray passing position in the third lens group G3 is close to the optical axis, and the aberration generated by the third lens group G3 is reduced.

  As described above, the aberration generated by the second lens group G2 decreases with focusing from infinity to a short distance, so the second lens group G2 having a positive refractive power and the third lens group G3 having a negative refractive power. As a result, the aberration generated by each becomes smaller. That is, if the signs of the aberrations generated by the second lens group G2 and the third lens group G3 are opposite signs, it is possible to suppress aberration fluctuations in the combined system of the second lens group G2 and the third lens group G3.

  For the above reason, by making the refractive power of the third lens group G3 negative, it is possible to suppress fluctuations in aberrations in the combined system of the second lens group G2 and the third lens group G3 during focusing, and the first lens group G1. It is possible to suppress aberration fluctuations accompanying focusing of the entire imaging optical system including the lens.

  As described above, the imaging optical system including the image stabilization mechanism according to the present invention can suppress fluctuations in off-axis aberrations such as coma due to movement of the second lens unit due to focusing by introducing the third lens unit. Therefore, it is suitable for a standard lens having a full diagonal angle of view of about 50 °, or a wide-angle lens having a larger angle of view, where the suppression of fluctuations in off-axis aberration is an issue. Further, the imaging optical system equipped with the image stabilization mechanism of the present invention is also suitable for a medium telephoto lens having a diagonal total field angle of about 30 °, which is less than that of a standard lens having a diagonal total field angle of about 50 °. Naturally applicable.

  Further, the third lens group G3 having a negative refractive power has effects such as suppressing the movement amount of the second lens group G2 due to focusing and suppressing the total length of the imaging optical system. Contributes to overall miniaturization.

  On the other hand, as described above, since the imaging element has a characteristic that the sensitivity is reduced with respect to light having a large incident angle, it is necessary to suppress the light emission angle from the imaging optical system. For this reason, when comparing the first lens group G1 having positive refractive power and the second lens group G2 having positive refractive power and the negative third lens group G3 facing each other with the aperture stop S interposed therebetween, The positive refractive power of one lens group G1 must be weaker.

  Similarly, since the third lens group G3 having a negative refractive power has an action of moving the exit pupil to the image side and increasing the light exit angle, the refractive power of the third lens group G3 is larger than that of the second lens group G2. It must be smaller.

  Next, the arrangement of the vibration isolation group will be described. In the third lens group G3 behind the lens system, the angle of the off-axis principal ray with respect to the optical axis becomes small due to the action of the positive second lens group G2 behind the stop S. This is suitable for arranging a vibration-proof group. Further, it is also preferable that the third lens group G3 does not move due to focusing and an increase in the weight of the focus group can be avoided.

  Aberration correction during image stabilization when the image stabilization group is not in the vicinity of the stop S will be qualitatively described with reference to the drawings. In general, the deviation angle of a light beam increases as the passing position of the light beam moves away from the optical axis. That is, it can be said that the occurrence of monochromatic aberration increases.

In the following explanation, the deflection angle of the light beam before and after the standard vibration isolation group is incident is δ, the deflection angle of the light beam before and after the shift vibration isolation group is incident is δ ′, and the light beam emitted from the standard vibration isolation group is The distance between the position incident on the image side group of the image stabilization group and the optical axis of the entire imaging optical system is h, and the light beam emitted from the image stabilization group in the shifted state enters the image side group of the image stabilization group. Let h ′ be the distance between the position and the optical axis of the entire imaging optical system.

  First, consider the case where the refractive power of the image stabilizing group is negative with reference to FIG. When the center axis of the vibration isolation group is shifted in a direction approaching the incident position of the light beam, as shown in the figure, the deviation angle δ ′ of the shift state is smaller than the deviation angle δ of the standard state, and the vibration isolation group is generated. The absolute value of aberration tends to be small. At this time, since the refractive power of the image stabilizing group is negative, h 'is smaller than h, and the absolute value of the aberration generated by the lens on the image side tends to be smaller than the image stabilizing group.

  As a result, the absolute value of the aberration generated by the image side group from both the image stabilization group and the image stabilization group becomes smaller. The aberrations generated by these groups are preferably different signs. Therefore, qualitatively, it is better that the refractive power of the image side group is different from that of the image stabilizing group.

  Therefore, when the refractive power of the image stabilizing group is negative, it is preferable that the image side group has a positive refractive power.

  Next, a case where the refractive power of the vibration proof group is positive will be considered using FIG. When the center axis of the vibration isolation group is shifted in a direction approaching the incident position of the light beam, as shown in the figure, the deviation angle δ ′ of the shift state is smaller than the deviation angle δ of the standard state, and the vibration isolation group is generated. The absolute value of aberration tends to be small. At this time, since the refractive power of the image stabilizing group is positive, h ′ is larger than h, and the absolute value of the aberration generated by the lens on the image side tends to be larger than the image stabilizing group.

  As a result, the absolute value of the aberration generated by the image stabilization group is small and the absolute value of the aberration generated by the image side group is larger than that of the image stabilization group. The aberrations generated by the group on the image side from the group and the image stabilizing group should have the same sign. Therefore, qualitatively, it is better that the refractive power of the image side group is the same as that of the image stabilizing group.

  Therefore, when the refractive power of the image stabilizing group is positive, it is preferable that the image side group has a positive refractive power.

  From these facts, when the anti-vibration group is not in the vicinity of the stop, regardless of the sign of the refractive power of the anti-vibration group, a group of positive refractive power is arranged on the image side from the anti-vibration group. Aberration fluctuation can be suppressed. Therefore, in the imaging optical system provided with the image stabilization mechanism of the present invention, the third lens group is configured by the negative refractive power 3a group G3a and the positive refractive power 3b group G3b, and the 3a group G3a performs the image stabilization. The configuration is to be performed. A lens group may be provided further on the object side than the 3a group G3a in the third lens group. However, since the mechanism configuration is complicated, it is disadvantageous for downsizing of the entire apparatus.

  Therefore, conditional expression 1 satisfied by the imaging optical system including the image stabilization mechanism according to the present invention is an infinitely focused state between the first lens group G1 and the combined system of the second lens group G2 and the third lens group G3. With respect to the ratio of the focal lengths, the preferable range for suppressing the total length of the optical system and the light emission angle from the lens is defined.

  If the lower limit of conditional expression 1 is not reached, the refractive power of the first lens group G1 will become strong and it will be difficult to suppress the light exit angle. On the other hand, if the upper limit of conditional expression 1 is exceeded, the refractive power of the second lens group G2 becomes strong, so that it becomes difficult to correct aberrations of the second lens group G2 and the third lens group G3. Further, since the refractive power of the combined system of the second lens group G2 and the third lens group G3 becomes stronger than that of the first lens group G1, and approaches a retrofocus type refractive power arrangement, the back focus becomes longer and the imaging optical system becomes longer. It becomes difficult to suppress the overall length of the entire system, and hinders the downsizing of the imaging optical system provided with the image stabilization mechanism.

  In addition, regarding the conditional expression 1 described above, by setting the lower limit value to 1.30 and further to 2.40, the above-described effect can be further ensured. Moreover, the above-mentioned effect can be made more reliable by setting the upper limit value to 7.00.

  Conditional expression 2 satisfied by the imaging optical system including the image stabilization mechanism according to the present invention is that the light emission angle from the lens and the aberration variation are related to the ratio of the focal lengths of the second lens group G2 and the third lens group G3. A preferable range for suppressing the above is defined.

  If the lower limit of conditional expression 2 is not reached, the refractive power of the third lens group G3 becomes weak, making it difficult to suppress aberration fluctuations associated with focusing. In addition, it becomes difficult to suppress the total length of the optical system and the amount of movement of the second lens group G2 due to focusing, which hinders downsizing of the imaging optical system provided with the image stabilization mechanism. On the other hand, if the upper limit of conditional expression 2 is exceeded, the refractive power of the third lens group G3 becomes strong and it becomes difficult to suppress the light emission angle.

  In addition, the conditional effect 2 mentioned above can make the above-mentioned effect more reliable by setting the lower limit to 0.02. Moreover, the above-mentioned effect can be made more reliable by setting the upper limit value to 0.30 and further to 0.25.

  Conditional expression 3 satisfied by the imaging optical system including the image stabilization mechanism of the present invention should be satisfied in order to suppress aberration fluctuations during image stabilization and focusing with respect to the refractive powers of the 3a group G3a and the 3b group G3b. It defines the range.

  If the refractive power of the 3a group G3a and the 3b group G3b increases below the lower limit of the conditional expression 3, the spherical aberration and coma aberration generated by each group increase, the aberration fluctuation during vibration isolation increases, and the image quality deteriorates greatly. Become. On the other hand, if the refractive power of the 3a group G3a and the 3b group G3b becomes smaller than the upper limit of the conditional expression 3, the generation of aberrations in the third lens group G3 as a whole becomes too small and it is difficult to suppress aberration fluctuations during focusing. It becomes. In addition, since the image shift amount per movement amount of the image stabilizing group cannot be increased, it is necessary to increase the amount of movement of the image stabilizing group, which increases the diameter of the lens barrel.

  Further, in the imaging optical system provided with the image stabilization mechanism of the present invention, two lenses in the first lens group G1, a positive lens having a convex surface facing the object side and a negative lens having a concave surface facing the image side in order from the object side. In the second lens group G2, a cemented lens composed of two lenses, a negative lens having a concave surface facing the object side and a positive lens having a convex surface facing the image side, in order from the object side. The lens DB2 is included. Thus, off-axis aberrations such as coma and astigmatism are corrected, and axial chromatic aberration is corrected in each of the first lens group G1 and the second lens group G2.

  If these cemented lenses are separated into air lenses, the degree of freedom of curvature increases by one surface, so there is a possibility that coma flare in the open state can be further reduced, but the performance degradation due to eccentricity of each lens increases, There is a possibility that the performance at the time of manufacture is lowered. Further, since lateral aberration near the center of the pupil tends to increase, there is a problem that the resolution does not increase even when the aperture stop S is stopped.

  Furthermore, since the second lens group G2 needs to have a large refractive power in order to suppress the light emission angle, it is preferable to have a biconvex positive lens on the image side of the cemented lens DB2.

  In the imaging optical system having the image stabilization mechanism of the present invention, it is desirable that the cemented surfaces of the cemented lens DB1 in the first lens group and the cemented lens DB2 in the second lens group satisfy the conditional expressions 4 and 5. These conditional expressions define preferable conditions with respect to the curvature radii of the cemented surfaces of the cemented lenses DB1 and DB2.

  If the curvature of each cemented surface increases beyond the range specified in conditional expressions 4 and 5, the occurrence of seventh-order coma aberration and fifth-order and seventh-order astigmatism occurring on the cemented surface increases, Performance degradation due to eccentricity becomes large. Moreover, the volume of the cemented lens increases and the weight increases. In particular, since the cemented lens DB2 is provided in the second lens group G2 that moves during focusing, an increase in weight becomes a serious problem.

  Furthermore, in the imaging optical system provided with the image stabilization mechanism of the present invention, it is desirable that the cemented lens DB1 in the first lens group is disposed on the most image side in the first lens group. As described above, since the cemented lens DB1 has the concave surface facing the image side, the image side surface has negative refractive power. By disposing this surface on the most image side in the first lens group, the refractive power arrangement inside the first lens group becomes close to a telephoto type, which is convenient for suppressing the entire length of the entire imaging optical system.

  In addition, since there is an aperture stop on the image side of the first lens group, and light beams of all angles of view are concentrated, the sensitivity of the change in aberration when the most image side element of the first lens group is decentered. Tends to be large. By disposing the cemented lens DB1 that satisfies the conditional expression 4 and suppresses the sensitivity of aberration change at the time of decentering on the most image side of the first lens group, it is possible to suppress the performance degradation due to the manufacturing error.

  Further, it is desirable that the imaging optical system provided with the image stabilization mechanism of the present invention satisfies the conditional expression 6. Conditional expression 6 satisfied by the imaging optical system provided with the image stabilization mechanism of the present invention is to suppress aberration fluctuations accompanying focusing with respect to the refractive index of at least one negative lens and one positive lens in the third lens group G3. The preferable conditions are defined. In order to cancel the aberration variation of the second lens group G2 having a larger refractive power, the third lens group G3 needs to increase the generation of aberration with respect to the refractive power.

  If the refractive index of at least one negative lens in the third lens group G3 becomes lower than the lower limit of the conditional expression 6, the coma aberration and distortion generated by the negative lens in the third lens group G3 increase and the performance deteriorates. In addition, aberration fluctuations due to decentering become large, and the performance at the time of manufacture deteriorates. On the other hand, if the refractive index of at least one negative lens in the third lens group G3 is higher than the upper limit of conditional expression 6, coma and distortion are less likely to occur, so it is difficult to suppress aberration fluctuations associated with focusing. Become.

  In addition, regarding the conditional expression 6 described above, by setting the lower limit value to 0.850, the above-described effect can be further ensured. Moreover, the above-mentioned effect can be made more reliable by setting the upper limit value to 0.985 and further to 0.900.

  Furthermore, it is desirable that the image forming optical system provided with the image stabilization mechanism of the present invention has a positive lens on the most image side of the third lens group G3. As described above, the third lens group G3 having negative refractive power tends to move the exit pupil to the image side and increase the exit angle of the principal ray at the periphery of the image. In order to eliminate this, by arranging the positive lens closest to the image side of the third lens group G3, the chief ray emission angle can be suppressed while weakening the power of the positive lens and suppressing the occurrence of aberration. .

Further, in the imaging optical system provided with the image stabilization mechanism of the present invention, it is desirable that the negative lens included in the third lens group G3 is one. In order to cancel out aberration fluctuations accompanying the movement of the second lens group G2 in the third lens group G3, it is necessary for the negative lens in the third lens group G3 to generate aberrations to some extent. For this purpose, it is preferable to reduce the number of negative lenses in the third lens group G3, and it is most preferable to use a single lens. That is, it is most preferable that the 3a group G3a is composed of one negative lens.
This leads to a reduction in the number of components, which is advantageous in reducing the size of the entire imaging optical system.
Further, the 3a group G3a is a vibration proof group. Since the vibration proof group can be reduced in weight by configuring the 3a group G3a as a single piece, the actuator can be reduced in size, which contributes to downsizing of the entire lens barrel.

  Furthermore, in the imaging optical system provided with the image stabilization mechanism of the present invention, the second lens group G2 includes two lenses, a negative lens having a concave surface facing the object side and a positive lens having a convex surface facing the image side in order from the object side. It is desirable that the lens is composed only of a cemented lens DB2 and a positive biconvex lens.

  As described above, it is desirable to have the cemented lens DB2 and the biconvex lens in order from the object side in order to sufficiently suppress aberration while suppressing the light emission angle and providing the refractive power necessary for focusing. Increasing the number of components is advantageous for aberration correction of the second lens group, but increases the weight of the second lens group and makes it difficult to reduce the weight of the focus group, which is one of the objects of the present invention. .

  In the imaging optical system provided with the image stabilization mechanism of the present invention, the following configuration is effective for improving the performance of the imaging optical system of the present invention.

  In order to suppress aberration fluctuations due to focusing, it is more preferable that any one or a plurality of surfaces of the second lens group G2 be aspherical to suppress the occurrence of aberrations in the second lens group G2.

  Although any surface can be aspherical, the correction effect can be obtained, but the surface closer to the object side of the second lens group G2 is more effective in correcting coma, and the surface closer to the image side of the second lens group G2 is astigmatism. It tends to be effective in correcting aberrations and distortions. Since the spherical aberration and coma aberration of the surface in the second lens group G2 are likely to change depending on the surface accuracy, it is more desirable that any surface of the biconvex positive lens that is easy to manufacture with high accuracy be an aspherical surface.

  In addition, astigmatism and the like can be corrected more satisfactorily by introducing an aspheric surface to the first lens group G1 and the third lens group G3.

  FIG. 1 is a lens configuration diagram of an imaging optical system provided with the image stabilization mechanism according to the first embodiment of the present invention.

  The first lens group G1 includes a cemented lens DB1 including a positive lens L1 having a convex surface facing the object side and a negative lens L2 having a concave surface facing the image side, and has a positive refractive power as a whole. .

  The second lens group G2 includes a cemented lens DB2 including a negative lens L3 having a concave surface facing the object side and a positive lens L4 having a convex surface facing the image side, and a biconvex positive lens L5. As a whole, it has a positive refractive power. The second lens group G2 moves toward the object side along the optical axis during focusing from infinity to a short distance.

  The third lens group G3 includes a negative refractive power 3a group G3a configured by a biconcave negative lens L6 and a positive refractive power 3b group G3b configured by a biconvex positive lens L7. It has a negative refractive power as a whole. The 3a group G3a performs vibration isolation by moving in a direction orthogonal to the optical axis.

  Further, the image side lens surface of the positive lens L5 and the image side lens surface of the positive lens L7 each have a predetermined aspherical shape.

  FIG. 8 is a lens configuration diagram of an imaging optical system including the image stabilization mechanism according to the second embodiment of the present invention.

  The first lens group G1 includes a cemented lens DB1 including a positive lens L1 having a convex surface facing the object side and a negative lens L2 having a concave surface facing the image side, and has a positive refractive power as a whole. .

  The second lens group G2 includes a cemented lens DB2 including a negative lens L3 having a concave surface facing the object side and a positive lens L4 having a convex surface facing the image side, and a biconvex positive lens L5. As a whole, it has a positive refractive power. The second lens group G2 moves toward the object side along the optical axis during focusing from infinity to a short distance.

  The third lens group G3 includes a negative refractive power 3a group G3a configured by a biconcave negative lens L6 and a positive refractive power 3b group G3b configured by a biconvex positive lens L7. It has a negative refractive power as a whole. The 3a group G3a performs vibration isolation by moving in a direction orthogonal to the optical axis.

  The image side lens surface of the positive lens L5 has a predetermined aspherical shape.

  FIG. 15 is a lens configuration diagram of an imaging optical system including the image stabilization mechanism according to the third embodiment of the present invention.

  The first lens group G1 includes a cemented lens DB1 including a positive lens L1 having a convex surface facing the object side and a negative lens L2 having a concave surface facing the image side, and has a positive refractive power as a whole. .

  The second lens group G2 includes a cemented lens DB2 including a negative lens L3 having a concave surface facing the object side and a positive lens L4 having a convex surface facing the image side, and a biconvex positive lens L5. As a whole, it has a positive refractive power. The second lens group G2 moves toward the object side along the optical axis during focusing from infinity to a short distance.

  The third lens group G3 includes a negative refractive power 3a group G3a configured by a biconcave negative lens L6 and a positive refractive power 3b group G3b configured by a biconvex positive lens L7. It has a negative refractive power as a whole. The 3a group G3a performs vibration isolation by moving in a direction orthogonal to the optical axis.

  Further, the image side lens surface of the positive lens L4 has a predetermined aspherical shape.

  FIG. 22 is a lens configuration diagram of an imaging optical system including the image stabilization mechanism according to the fourth embodiment of the present invention.

  The first lens group G1 is a cemented lens DB1 including a meniscus negative lens L1 having a convex surface facing the object side, a positive lens L2 having a convex surface facing the object side, and a negative lens L3 having a concave surface facing the image side. It has a positive refractive power as a whole.

  The second lens group G2 includes a cemented lens DB2 including a negative lens L4 having a concave surface facing the object side and a positive lens L5 having a convex surface facing the image side, and a biconvex positive lens L6. As a whole, it has a positive refractive power. The second lens group G2 moves toward the object side along the optical axis during focusing from infinity to a short distance.

  The third lens group G3 is composed of a negative refractive power 3a group G3a composed of a biconcave negative lens L7 and a positive refractive power 3b group G3b composed of a biconvex positive lens L8. It has a negative refractive power as a whole. The 3a group G3a performs vibration isolation by moving in a direction orthogonal to the optical axis.

  The image side lens surface of the positive lens L5 has a predetermined aspherical shape.

  FIG. 29 is a lens configuration diagram of an imaging optical system including the image stabilization mechanism according to the fifth embodiment of the present invention.

  The first lens group G1 is a cemented lens DB1 including a meniscus positive lens L1 having a convex surface facing the object side, a positive lens L2 having a convex surface facing the object side, and a negative lens L3 having a concave surface facing the image side. It has a positive refractive power as a whole.

  The second lens group G2 includes a cemented lens DB2 including a negative lens L4 having a concave surface facing the object side and a positive lens L5 having a convex surface facing the image side, and a biconvex positive lens L6. As a whole, it has a positive refractive power. The second lens group G2 moves toward the object side along the optical axis during focusing from infinity to a short distance.

  The third lens group G3 has a negative refractive power 3a group G3a composed of a meniscus negative lens L7 having a convex surface facing the object side, and a positive refractive power composed of a biconvex positive lens L8. 3b group G3b, and has a negative refractive power as a whole. The 3a group G3a performs vibration isolation by moving in a direction orthogonal to the optical axis.

  Further, the object side lens surface of the positive lens L1 and the image side lens surface of the positive lens L5 each have a predetermined aspherical shape.

  FIG. 36 is a lens configuration diagram of an imaging optical system including the image stabilization mechanism according to Embodiment 6 of the present invention.

  The first lens group G1 includes a cemented lens DB1 including a positive lens L1 having a convex surface facing the object side and a negative lens L2 having a concave surface facing the image side, and has a positive refractive power as a whole. .

  The second lens group G2 includes a cemented lens DB2 including a negative lens L3 having a concave surface facing the object side and a positive lens L4 having a convex surface facing the image side, and a biconvex positive lens L5. As a whole, it has a positive refractive power. The second lens group G2 moves toward the object side along the optical axis during focusing from infinity to a short distance.

  The third lens group G3 has a negative refractive power 3a group G3a composed of a meniscus negative lens L6 with a convex surface facing the object side, and a positive refractive power composed of a biconvex positive lens L7. 3b group G3b, and has a negative refractive power as a whole. The 3a group G3a performs vibration isolation by moving in a direction orthogonal to the optical axis.

  Further, the image side lens surface of the positive lens L5 and the image side lens surface of the positive lens L7 each have a predetermined aspherical shape.

  FIG. 43 is a lens configuration diagram of an imaging optical system provided with the image stabilization mechanism of Example 7 of the present invention.

  The first lens group G1 includes a cemented lens DB1 including a positive lens L1 having a convex surface facing the object side and a negative lens L2 having a concave surface facing the image side, and has a positive refractive power as a whole. .

  The second lens group G2 includes a cemented lens DB2 including a negative lens L3 having a concave surface facing the object side and a positive lens L4 having a convex surface facing the image side, and a biconvex positive lens L5. As a whole, it has a positive refractive power. The second lens group G2 moves toward the object side along the optical axis during focusing from infinity to a short distance.

  The third lens group G3 includes a negative refractive power 3a group G3a configured by a biconcave negative lens L6 and a positive refractive power 3b group G3b configured by a biconvex positive lens L7. It has a negative refractive power as a whole. The 3a group G3a performs vibration isolation by moving in a direction orthogonal to the optical axis.

  Further, the image side lens surface of the positive lens L5 and the image side lens surface of the positive lens L7 each have a predetermined aspherical shape.

  FIG. 50 is a lens configuration diagram of an imaging optical system including the image stabilization mechanism according to the eighth embodiment of the present invention.

  The first lens group G1 includes a cemented lens DB1 including a positive lens L1 having a convex surface facing the object side and a negative lens L2 having a concave surface facing the image side, and has a positive refractive power as a whole. .

  The second lens group G2 includes a cemented lens DB2 including a negative lens L3 having a concave surface facing the object side and a positive lens L4 having a convex surface facing the image side, and a biconvex positive lens L5. As a whole, it has a positive refractive power. The second lens group G2 moves toward the object side along the optical axis during focusing from infinity to a short distance.

  The third lens group G3 includes a negative refractive power 3a group G3a configured by a biconcave negative lens L6 and a positive refractive power 3b group G3b configured by a biconvex positive lens L7. It has a negative refractive power as a whole. The 3a group G3a performs vibration isolation by moving in a direction orthogonal to the optical axis.

  Further, the image side lens surface of the positive lens L5 and the image side lens surface of the positive lens L7 each have a predetermined aspherical shape.

  FIG. 57 is a lens configuration diagram of an imaging optical system including the image stabilization mechanism according to Example 9 of the present invention.

  The first lens group G1 is a cemented lens DB1 including a meniscus negative lens L1 having a convex surface facing the object side, a positive lens L2 having a convex surface facing the object side, and a negative lens L3 having a concave surface facing the image side. It has a positive refractive power as a whole.

  The second lens group G2 includes a cemented lens DB2 including a negative lens L4 having a concave surface facing the object side and a positive lens L5 having a convex surface facing the image side, and a biconvex positive lens L6. As a whole, it has a positive refractive power. The second lens group G2 moves toward the object side along the optical axis during focusing from infinity to a short distance.

  The third lens group G3 is composed of a negative refractive power 3a group G3a composed of a biconcave negative lens L7 and a positive refractive power 3b group G3b composed of a biconvex positive lens L8. It has a negative refractive power as a whole. The 3a group G3a performs vibration isolation by moving in a direction orthogonal to the optical axis.

  Further, the object side lens surface of the positive lens L6 and the image side lens surface of the positive lens L8 each have a predetermined aspherical shape.

  FIG. 64 is a lens configuration diagram of an imaging optical system including the image stabilization mechanism according to Example 10 of the present invention.

  The first lens group G1 includes a cemented lens DB1 including a positive lens L1 having a convex surface facing the object side and a negative lens L2 having a concave surface facing the image side, and has a positive refractive power as a whole. .

  The second lens group G2 includes a cemented lens DB2 including a negative lens L3 having a concave surface facing the object side and a positive lens L4 having a convex surface facing the image side, and a biconvex positive lens L5. As a whole, it has a positive refractive power. The second lens group G2 moves toward the object side along the optical axis during focusing from infinity to a short distance.

  The third lens group G3 includes a negative refractive power 3a group G3a configured by a biconcave negative lens L6 and a positive refractive power 3b group G3b configured by a biconvex positive lens L7. It has a negative refractive power as a whole. The 3a group G3a performs vibration isolation by moving in a direction orthogonal to the optical axis.

  Further, the image side lens surface of the positive lens L5 and the image side lens surface of the positive lens L7 each have a predetermined aspherical shape.

  FIG. 71 is a lens configuration diagram of an imaging optical system including the image stabilization mechanism according to Example 11 of the present invention.

  The first lens group G1 includes a cemented lens DB1 including a positive lens L1 having a convex surface facing the object side and a negative lens L2 having a concave surface facing the image side, and has a positive refractive power as a whole. .

  The second lens group G2 includes a cemented lens DB2 including a negative lens L3 having a concave surface facing the object side and a positive lens L4 having a convex surface facing the image side, and a biconvex positive lens L5. As a whole, it has a positive refractive power. The second lens group G2 moves toward the object side along the optical axis during focusing from infinity to a short distance.

  The third lens group G3 is a positive lens composed of a negative refractive power 3a group G3a composed of a biconcave negative lens L6, a biconvex positive lens L7, and a biconvex positive lens L8. It consists of a 3b group G3b having a refractive power, and has a negative refractive power as a whole. The 3a group G3a performs vibration isolation by moving in a direction orthogonal to the optical axis.

  The image side lens surface of the positive lens L5 has a predetermined aspherical shape.

  FIG. 78 is a lens configuration diagram of the imaging optical system according to Example 12 of the present invention.

  The first lens group G1 includes a meniscus positive lens L1 having a convex surface facing the object side, a meniscus positive lens L2 having a convex surface facing the object side, and a meniscus negative lens L3 having a concave surface facing the image side. And a cemented lens DB1 composed of a positive lens L4 having a convex surface facing the object side and a negative lens L5 having a concave surface facing the image side, and has a positive refractive power as a whole.

  The second lens group G2 includes a cemented lens DB2 including a negative lens L6 having a concave surface facing the object side and a positive lens L7 having a convex surface facing the image side, and a biconvex positive lens L8. As a whole, it has a positive refractive power. The second lens group G2 moves toward the object side along the optical axis during focusing from infinity to a short distance.

  The third lens group G3 has a negative refractive power 3a group G3a composed of a biconcave negative lens L9 and a positive refractive power composed of a meniscus positive lens L10 having a convex surface facing the object side. 3b group and has a negative refractive power as a whole. The 3a group G3a performs vibration isolation by moving in a direction orthogonal to the optical axis.

  The image side lens surface of the positive lens L8 has a predetermined aspheric shape.

  FIG. 85 is a lens configuration diagram of the imaging optical system according to Example 13 of the present invention.

  The first lens group G1 includes a meniscus positive lens L1 having a convex surface facing the object side, a meniscus positive lens L2 having a convex surface facing the object side, and a meniscus negative lens L3 having a concave surface facing the image side. And a cemented lens DB1 composed of a positive lens L4 having a convex surface facing the object side and a negative lens L5 having a concave surface facing the image side, and has a positive refractive power as a whole.

  The second lens group G2 includes a cemented lens DB2 including a negative lens L6 having a concave surface facing the object side and a positive lens L7 having a convex surface facing the image side, and a biconvex positive lens L8. As a whole, it has a positive refractive power. The second lens group G2 moves toward the object side along the optical axis during focusing from infinity to a short distance.

  The third lens group G3 is composed of a negative refractive power 3a group G3a composed of a biconcave negative lens L9 and a positive refractive power 3b group composed of a biconvex lens L10. As negative power. The 3a group G3a performs vibration isolation by moving in a direction orthogonal to the optical axis.

  The image side lens surface of the positive lens L8 has a predetermined aspheric shape.

  FIG. 92 is a lens configuration diagram of the imaging optical system according to Example 14 of the present invention.

  The first lens group G1 is a cemented lens DB1 including a meniscus positive lens L1 having a convex surface facing the object side, a positive lens L2 having a convex surface facing the object side, and a negative lens L3 having a concave surface facing the image side. It has a positive refractive power as a whole.

  The second lens group G2 includes a cemented lens DB2 including a negative lens L4 having a concave surface facing the object side and a positive lens L5 having a convex surface facing the image side, and a biconvex positive lens L6. As a whole, it has a positive refractive power. The second lens group G2 moves toward the object side along the optical axis during focusing from infinity to a short distance.

  The third lens group G3 includes a negative refractive power 3a group G3a constituted by a biconcave negative lens L7, and a positive refractive power 3b group constituted by a biconvex lens L8. As negative power. The 3a group G3a performs vibration isolation by moving in a direction orthogonal to the optical axis.

  The image side lens surface of the positive lens L6 has a predetermined aspheric shape.

  Specific numerical data of numerical examples corresponding to the respective embodiments described above are shown below. In [Overall specifications] of each numerical example, f represents a focal length, Fno represents an F number, and 2ω represents a total angle of view. In [Lens Specifications], the first column number is the lens surface number from the object side, the second column r is the radius of curvature of each lens surface, the third column d is the lens surface spacing, and the fourth column nd is The refractive index with respect to the d-line (wavelength 587.56 nm) and νd represents the Abbe number with respect to the d-line (wavelength 587.56 nm).

  * (Asterisk) attached to the lens surface number in the first row indicates that the lens surface shape is an aspherical surface. The “aperture stop” in the second row represents the position of the stop surface, and Bf in the third row represents the back focus.

  [Variable interval] indicates the value of each variable interval in focusing.

  [Aspheric coefficient] indicates an aspheric coefficient that gives the aspheric shape of the lens surface marked with * in [Lens Specifications]. The shape of the aspheric surface is y for the displacement from the optical axis in the direction perpendicular to the optical axis, z for the displacement (sag amount) from the intersection of the aspheric surface and the optical axis in the optical axis direction, and r for the radius of curvature of the reference spherical surface. When the conic coefficient is K, 4, 6, 8, and the 10th-order aspheric coefficient is A4, A6, A8, and A10, the coordinates of the aspheric surface are expressed by the following equations.

  In addition, in the values of all the following specifications, the stated focal length f, radius of curvature r, lens surface interval d, and other length units 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 values of conditional expressions in the respective embodiments described above is shown below.

Example 1
[Overall specifications]
Shooting distance INF
f 30.83
Fno 2.89
2ω 50.49

[Lens specifications]
rd nd νd
[1] 17.7672 3.1821 1.88300 40.80
[2] -1000.0000 0.8000 1.58144 40.89
[3] 12.9742 2.6198
[4] Aperture stop d4
[5] -10.0295 0.8000 1.69895 30.05
[6] 58.7192 3.8254 1.80420 46.50
[7] -15.7253 0.1500
[8] 47.8215 3.6590 1.77250 49.62
* [9] -27.3923 d9
[10] -97.3976 1.0000 1.56732 42.84
[11] 24.1411 4.4473
[12] 88.7361 2.8926 1.77250 49.62
* [13] -67.2193 Bf
*: Aspheric

[Variable interval]
Shooting distance d4 d9 Bf
INF 6.9859 1.5000 20.4045
500mm 5.6552 2.8307 20.4045

[Aspheric coefficient]
9th 13th
A4 1.68830E-05 9.50840E-08
A6 -6.94468E-09 -5.47977E-09
A8 2.50342E-11 2.45567E-11
A10 0.00000E + 00 0.00000E + 00

Example 2
[Overall specifications]
Shooting distance INF
f 30.92
Fno 2.91
2ω 50.28

[Lens specifications]
rd nd νd
[1] 17.8828 3.0675 1.88300 40.80
[2] -466.4970 0.8000 1.58144 40.89
[3] 13.0047 2.5427
[4] Aperture stop d4
[5] -10.2042 0.8000 1.67270 32.17
[6] 36.9328 3.9392 1.80420 46.50
[7] -16.8128 0.1500
[8] 50.1843 3.5110 1.77250 49.62
* [9] -26.8479 d9
[10] -80.8366 1.0000 1.60342 38.01
[11] 25.2151 4.5111
[12] 101.7470 2.8930 1.80420 46.50
[13] -60.0440 Bf
*: Aspheric

[Variable interval]
Shooting distance d4 d9 Bf
INF 6.7985 1.5000 20.6687
500mm 5.5178 2.7807 20.6688

[Aspheric coefficient]
9 sides
A4 2.03217E-05
A6 -1.99227E-08
A8 1.55204E-10
A10 0.00000E + 00

Example 3
[Overall specifications]
Shooting distance INF
f 30.81
Fno 2.90
2ω 50.43

[Lens specifications]
rd nd νd
[1] 16.3182 3.1496 1.88300 40.80
[2] 1000.0000 0.8500 1.60342 38.01
[3] 11.9440 2.1808
[4] Aperture stop d4
[5] -10.2428 0.8500 1.67270 32.17
[6] 100.7580 3.7977 1.77250 49.62
* [7] -15.0281 0.1500
[8] 55.9362 3.2307 1.83481 42.72
[9] -36.4658 d9
[10] -64.6517 1.0000 1.67270 32.17
[11] 29.6972 2.9631
[12] 216.4930 3.6631 1.77250 49.62
[13] -31.3466 Bf
*: Aspheric

[Variable interval]
Shooting distance d4 d9 Bf
INF 6.8178 2.9737 20.7178
500mm 5.2020 4.5895 20.7178

[Aspheric coefficient]
7 sides
A4 1.07514E-05
A6 7.51773E-08
A8 0.00000E + 00
A10 0.00000E + 00

Example 4
[Overall specifications]
Shooting distance INF
f 30.91
Fno 2.91
2ω 50.28

[Lens specifications]
rd nd νd
[1] 21.1515 1.0000 1.51742 52.15
[2] 14.2703 2.8609
[3] 16.3026 3.8285 1.80420 46.50
[4] -79.9177 1.0332 1.54814 45.82
[5] 13.8102 2.8556
[6] Aperture stop d6
[7] -11.0738 0.8500 1.60342 38.01
[8] 34.1395 3.5895 1.77250 49.62
* [9] -19.3756 0.1500
[10] 118.722 3.5280 1.72916 54.67
[11] -22.6131 d11
[12] -46.4782 1.0000 1.67270 32.17
[13] 33.6717 2.0043
[14] 155.728 3.4080 1.80420 46.50
[15] -32.2286 Bf
*: Aspheric

[Variable interval]
Shooting distance d6 d11 Bf
INF 6.7621 1.5000 25.3043
500mm 5.0986 3.1635 25.3042

[Aspheric coefficient]
9 sides
A4 2.11124E-05
A6 1.22452E-07
A8 0.00000E + 00
A10 0.00000E + 00

Example 5
[Overall specifications]
Shooting distance INF
f 30.77
Fno 2.47
2ω 50.43

[Lens specifications]
rd nd νd
* [1] 30.4647 2.0493 1.80610 40.73
[2] 70.7560 1.6595
[3] 45.0084 2.6177 1.88300 40.80
[4] -45.0084 1.0353 1.60342 38.01
[5] 16.3355 1.9370
[6] Aperture stop d6
[7] -10.1505 1.0665 1.67270 32.17
[8] 1000.0000 4.8298 1.77250 49.62
* [9] -14.1058 0.1500
[10] 41.3218 3.8985 1.80420 46.50
[11] -55.6171 d11
[12] 330.7410 1.0000 1.64769 33.84
[13] 22.4954 1.5801
[14] 47.0046 3.0802 1.72916 54.67
[15] -132.7210 Bf
*: Aspheric

[Variable interval]
Shooting distance d6 d11 Bf
INF 8.2303 1.5000 22.7049
500mm 6.6333 3.0970 22.7049

[Aspheric coefficient]
1 side 9 sides
A4 -5.37530E-06 6.75573E-06
A6 -1.74772E-08 -1.94113E-08
A8 0.00000E + 00 5.96039E-10
A10 0.00000E + 00 0.00000E + 00

Example 6
[Overall specifications]
Shooting distance INF
f 30.60
Fno 2.47
2ω 50.72

[Lens specifications]
rd nd νd
[1] 20.4321 3.6701 1.88300 40.80
[2] 1969.5900 1.2000 1.60342 38.01
[3] 14.1396 3.9679
[4] Aperture stop d4
[5] -10.2071 0.8500 1.64769 33.84
[6] 31.0579 4.9674 1.80420 46.50
[7] -19.4887 0.1500
[8] 49.8435 4.6667 1.77250 49.62
* [9] -24.8436 d9
[10] 73.6332 1.0000 1.71736 29.50
[11] 23.1034 2.5618
[12] 69.7780 2.0789 1.77250 49.62
* [13] -875.8660 Bf
*: Aspheric

[Variable interval]
Shooting distance d4 d9 Bf
INF 8.0709 1.5000 22.6437
500mm 6.7216 2.8493 22.6437

[Aspheric coefficient]
9th 13th
A4 2.64598E-05 -8.41610E-07
A6 -1.67129E-09 2.18423E-08
A8 5.88092E-11 4.26137E-13
A10 0.00000E + 00 0.00000E + 00

Example 7
[Overall specifications]
Shooting distance INF
f 28.77
Fno 2.91
2ω 53.60

[Lens specifications]
rd nd νd
[1] 18.3732 3.0553 1.88300 40.80
[2] -1225.7800 0.8000 1.56732 42.84
[3] 12.9748 2.7044
[4] Aperture stop d4
[5] -9.7411 0.8000 1.72825 28.32
[6] 95.1258 4.3138 1.80420 46.50
[7] -14.9218 0.1500
[8] 43.1304 4.3678 1.77250 49.62
* [9] -28.8136 d9
[10] -248.3050 1.0000 1.56732 42.84
[11] 24.5497 2.9966
[12] 96.4861 2.6302 1.77250 49.62
* [13] -73.0893 Bf
*: Aspheric

[Variable interval]
Shooting distance d4 d9 Bf
INF 7.4725 1.5000 20.5277
500mm 6.1644 2.8081 20.5277

[Aspheric coefficient]
9th 13th
A4 1.46389E-05 3.05823E-06
A6 -1.48270E-08 3.48667E-09
A8 3.04390E-11 1.21760E-10
A10 0.00000E + 00 0.00000E + 00

Example 8
[Overall specifications]
Shooting distance INF
f 36.83
Fno 2.92
2ω 42.87

[Lens specifications]
rd nd νd
[1] 18.7768 3.8986 1.88300 40.80
[2] 147.9180 1.2000 1.60342 38.01
[3] 14.1942 3.1885
[4] Aperture stop d4
[5] -11.6016 1.1500 1.71736 29.50
[6] 67.9589 3.7918 1.80420 46.50
[7] -18.8419 0.4530
[8] 67.6991 4.0561 1.77250 49.62
* [9] -28.8070 d9
[10] -471.2120 1.0000 1.51742 52.15
[11] 27.0408 2.6038
[12] 122.6210 2.4355 1.77250 49.62
* [13] -92.8949 Bf
*: Aspheric

[Variable interval]
Shooting distance d4 d9 Bf
INF 8.4761 3.2528 24.1734
500mm 6.1681 5.5609 24.1734

[Aspheric coefficient]
9th 13th
A4 1.13631E-05 -1.10755E-06
A6 5.04777E-09 -3.33029E-09
A8 0.00000E + 00 0.00000E + 00
A10 0.00000E + 00 0.00000E + 00

Example 9
[Overall specifications]
Shooting distance INF
f 24.72
Fno 2.90
2ω 60.91

[Lens specifications]
rd nd νd
[1] 34.3141 1.0000 1.49700 81.61
[2] 14.0764 4.5148
[3] 27.8352 2.6364 1.80420 46.50
[4] -32.4074 0.8000 1.51742 52.15
[5] 51.1758 1.2119
[6] Aperture stop d6
[7] -10.4135 1.1500 1.76182 26.61
[8] -811.4690 4.3029 1.80420 46.50
[9] -14.9803 0.1500
[10] 103.7640 4.2389 1.75501 51.16
* [11] -20.0298 d11
[12] -125.3740 1.0000 1.60342 38.01
[13] 33.9463 0.9100
[14] 68.7625 1.8898 1.77250 49.62
* [15] -1092.8400 Bf
*: Aspheric

[Variable interval]
Shooting distance d6 d11 Bf
INF 7.6621 1.5000 23.7560
500mm 6.8124 2.3497 23.7560

[Aspheric coefficient]
11 faces 15 faces
A4 2.88489E-05 -1.33539E-06
A6 -1.34435E-08 4.43316E-08
A8 0.00000E + 00 1.70897E-10
A10 0.00000E + 00 -4.28211E-14

Example 10
[Overall specifications]
Shooting distance INF
f 38.82
Fno 2.92
2ω 40.96

[Lens specifications]
rd nd νd
[1] 18.7363 3.8808 1.88300 40.80
[2] 176.1670 1.2000 1.60342 38.01
[3] 14.3179 2.8894
[4] Aperture stop d4
[5] -12.5113 1.1500 1.69895 30.05
[6] 50.5350 3.3293 1.80420 46.50
[7] -21.1597 1.3982
[8] 70.6099 3.2915 1.77250 49.62
* [9] -28.4884 d9
[10] -88.6725 1.0000 1.51742 52.15
[11] 29.4400 2.6671
[12] 110.3830 2.3688 1.77250 49.62
* [13] -83.6235 Bf
*: Aspheric

[Variable interval]
Shooting distance d4 d9 Bf
INF 7.7649 1.9800 26.8193
500mm 5.4180 4.3269 26.8194

[Aspheric coefficient]
9th 13th
A4 1.29698E-05 -2.20389E-06
A6 5.07127E-09 -7.24219E-09
A8 0.00000E + 00 0.00000E + 00
A10 0.00000E + 00 0.00000E + 00

Example 11
[Overall specifications]
Shooting distance INF
f 30.81
Fno 2.91
2ω 50.52

[Lens specifications]
rd nd νd
[1] 17.6398 3.1831 1.88300 40.80
[2] -661.0788 0.8000 1.58144 40.89
[3] 12.8754 2.5733
[4] Aperture stop d4
[5] -9.9833 0.8000 1.69895 30.05
[6] 54.4546 3.8772 1.80420 46.50
[7] -15.5512 0.1500
[8] 44.9191 3.6762 1.77250 49.62
* [9] -28.2894 d9
[10] -94.3498 1.0000 1.54814 45.82
[11] 23.4326 4.2896
[12] 103.2251 2.0675 1.71300 53.94
[13] -200.0487 0.1500
[14] 596.8248 1.9200 1.71300 53.94
[15] -91.3509 Bf
*: Aspheric

[Variable interval]
Shooting distance d4 d9 Bf
INF 6.9886 1.2000 19.8474
500mm 5.6980 2.4906 19.8474

[Aspheric coefficient]
9 sides
A4 1.66558E-05
A6 -1.50233E-08
A8 9.05044E-11
A10 0.00000E + 00

Example 12
[Overall specifications]
Shooting distance INF
f 49.97
Fno 2.91
2ω 31.29

[Lens specifications]
rd nd vd
[1] 25.5676 3.2132 1.91082 35.25
[2] 76.6739 0.1500
[3] 18.6018 3.0735 1.88100 40.14
[4] 25.1540 0.8500 1.69895 30.05
[5] 14.0047 1.1254
[6] 18.1926 2.8366 1.49700 81.61
[7] 471.3847 0.8500 1.76182 26.61
[8] 16.2708 3.5236
[9] Aperture stop d9
[10] -13.3018 0.8500 1.61293 36.96
[11] 45.3569 3.3222 1.77250 49.62
[12] -34.6306 0.1500
[13] 88.7278 4.3443 1.77250 49.47
* [14] -21.7125 d14
[15] -65.7271 0.8500 1.72916 54.67
[16] 56.2018 1.7879
[17] 57.3786 2.2311 1.80518 25.46
[18] 1000.0000 Bf
*: Aspheric

[Variable interval]
Shooting distance d9 d14 Bf
INF 11.1929 1.2000 18.0523
800mm 8.3863 4.0066 18.0523

[Aspheric coefficient]
14
A4 2.14963E-05
A6 1.81277E-08
A8 0.00000E + 00
A10 0.00000E + 00

Example 13
[Overall specifications]
Shooting distance INF
f 49.83
Fno 2.91
2ω 31.37

[Lens specifications]
rd nd vd
[1] 25.6932 2.9860 1.88100 40.14
[2] 78.1195 0.1500
[3] 16.7234 2.5121 1.88100 40.14
[4] 23.5258 0.8500 1.68893 31.16
[5] 13.0992 1.1461
[6] 17.3301 2.8747 1.49700 81.61
[7] 206.6586 0.8500 1.71736 29.50
[8] 14.6907 3.6520
[9] Aperture stop d9
[10] -14.8255 0.8500 1.59551 39.22
[11] 51.9204 3.1601 1.77250 49.62
[12] -41.3253 0.7021
[13] 69.7649 4.5681 1.77250 49.47
* [14] -24.4434 d14
[15] -45.1987 0.8500 1.49700 81.61
[16] 33.3998 2.0054
[17] 40.2381 3.4071 1.51823 58.96
[18] -158.4762 Bf
*: Aspheric

[Variable interval]
Shooting distance d9 d14 Bf
INF 12.0088 1.2000 15.5014
800mm 9.0132 4.1956 15.5014

[Aspheric coefficient]
14
A4 1.66652E-05
A6 4.92275E-09
A8 0.00000E + 00
A10 0.00000E + 00

Example 14
[Overall specifications]
Shooting distance INF
f 54.15
Fno 2.91
2ω 28.99

[Lens specifications]
rd nd vd
[1] 22.8494 3.8512 1.88100 40.14
[2] 72.9156 4.2501
[3] 14.7989 4.0964 1.49700 81.61
[4] -596.7061 0.8500 1.72825 28.32
[5] 11.5054 4.0442
[6] Aperture stop d6
[7] -13.2230 0.8500 1.65844 50.85
[8] 278.9063 4.5406 1.77250 49.62
[9] -19.5173 0.1500
[10] 61.1270 3.6152 1.77250 49.47
* [11] -45.4303 d11
[12] -46.4826 0.8500 1.59349 67.00
[13] 52.9372 3.6470
[14] 184.5884 2.5964 1.80420 46.50
[15] -77.8785 Bf
*: Aspheric

[Variable interval]
Shooting distance d6 d11 Bf
INF 12.0519 1.2000 14.4036
800mm 8.3631 4.8887 14.4037

[Aspheric coefficient]
11
A4 1.31775E-06
A6 -2.40905E-09
A8 0.00000E + 00
A10 0.00000E + 00

[Values for conditional expressions]
Conditional expression 1 Conditional expression 2 Conditional expression 3 Conditional expression 4 Conditional expression 5 Conditional expression 6
Conditional expression f1 / f2-3 | f2 / f3 | | f3axf3b / f ^ 2 | | RDB1 / f | | RDB2 / f | n3a / n3b
Range 1.20-7.50 0.01-0.35 0.90-6.50 1.00- 0.85- 0.800-0.990
Example 1 3.235 0.140 1.786 32.44 1.90 0.884
Example 2 3.225 0.148 1.572 15.09 1.19 0.889
Example 3 3.568 0.014 1.132 32.45 3.27 0.944
Example 4 5.629 0.020 1.012 2.59 1.10 0.927
Example 5 4.725 0.116 1.889 1.46 32.49 0.953
Example 6 6.586 0.187 4.232 64.36 1.01 0.969
Example 7 3.963 0.115 2.574 42.60 3.31 0.884
Example 8 3.278 0.138 2.504 4.02 1.85 0.856
Example 9 3.656 0.220 6.058 1.31 32.83 0.905
Example 10 2.745 0.180 1.750 4.54 1.30 0.856
Example 11 3.156 0.152 1.869 21.46 1.77 0.904
Example 12 1.461 0.322 1.253 9.43 0.91 0.958
Example 13 1.427 0.285 0.966 4.15 1.04 0.986
Example 14 1.353 0.256 0.970 11.02 5.15 0.883

G1 First lens group G2 Second lens group G3 Third lens group DB1 Joint lens DB2 Joint lens G3a 3a group G3b 3b group S Aperture stop

Claims (5)

In order from the object side, the first lens group having a positive refractive power, an aperture stop, a second lens group having a positive refractive power, and a third lens group having a negative refractive power,
During focusing from infinity to short distance, the second lens group moves to the object side along the optical axis, and the third lens group sequentially has a negative refractive power 3a group and a positive refractive power 3b group from the object side. The 3a group includes one negative lens, the 3b group has a positive lens closest to the image side, and performs vibration isolation by moving the 3a group in a direction perpendicular to the optical axis. An imaging optical system provided with an image stabilization mechanism that satisfies the following conditional expression:
(1) 1.20 <f1 / f23 <7.50
(2) 0.01 <| f2 / f3 | <0.35
(3) 0.90 <| f3a × f3b / f ^ 2 | <6.50
However,
fi: focal length of the i-th lens group f23: combined focal length f3a: focal length of the 3a group at the time of focusing on the infinity of the second lens group and the third lens group f3b: focal length of the 3b group f: imaging optical system Focal length when focusing on infinity of the entire system The first lens group includes a cemented lens DB1 of a positive lens having a convex surface facing the object side in order from the object side and a negative lens having a concave surface facing the image side, and the second lens group is in order from the object side. 2. The lens unit is composed of a cemented lens DB2 composed of a negative lens having a concave surface facing the object side and a positive lens having a convex surface facing the image side, and a biconvex positive lens, and satisfies the following conditional expression: An imaging optical system provided with the image stabilization mechanism described in 1.
(4) | RDB1 / f |> 1.00
(5) | RDB2 / f |> 0.85
However,
RDB1: radius of curvature of the cemented surface of the cemented lens DB1 RDB2: radius of curvature of the cemented surface of the cemented lens DB2   3. The imaging optical system having an image stabilization mechanism according to claim 2, wherein the cemented lens DB <b> 1 is located closest to the image side among the cemented lenses included in the first lens group. The imaging optical system provided with the image stabilization mechanism according to any one of claims 1 to 3, wherein the following conditional expression is satisfied.
(6) 0.800 <n3a / n3b <0.990
However,
n3a: Maximum value of the refractive index of the negative lens constituting the 3a group n3b: Minimum value of the refractive index of the positive lens constituting the 3b group The second lens group includes, in order from the object side, only a cemented lens DB2 of a negative lens having a concave surface facing the object side and a positive lens having a convex surface facing the image side, and a biconvex positive lens. An imaging optical system comprising the image stabilization mechanism according to claim 1 .

Images