JP7080483B2 - Variable magnification imaging optical system - Google Patents

Description

The present invention relates to a variable magnification imaging optical system used in a still camera, a video camera, etc., and particularly to a variable magnification imaging optical system having a narrow angle of view at the telephoto end, a large variable magnification, and an anti-vibration function. Is.

Anti-vibration functions are being increasingly installed in imaging optical systems used in digital still cameras and the like, and it has become possible to reduce failures due to camera shake even when taking photographs using a super-telephoto lens. This makes shooting at super-telephoto more familiar, and the demand for super-telephoto lenses is increasing. With the increase in demand for super-telephoto lenses, a large magnification ratio that can handle more subjects is required, and with the recent increase in the number of pixels of digital cameras and the shift to low-pass filters, improvement in imaging performance is also required.

Patent Documents 1 and 2 describe an example of a variable magnification imaging optical system having a vibration-proof function and having a large scaling ratio of about 2.5 degrees or less at a half angle of view at the telephoto end.

Japanese Unexamined Patent Publication No. 2011-39260 Japanese Unexamined Patent Publication No. 2016-142795

In a super-telephoto optical system with a narrow angle of view at the telephoto end, the focal length tends to be longer with respect to the diagonal length of the imager, and the total length of the optical system tends to increase accordingly. Therefore, miniaturization of the total length becomes an issue. If the telephoto type refractive power arrangement is strengthened to increase the image magnification of the rear lens group in order to reduce the overall length, the change in the ray arrival position inevitably becomes large with respect to the change in the specifications of the front group. For this reason, it is difficult to correct aberrations based on the design values of the entire system, and aberration fluctuations due to manufacturing errors are large, making it difficult to guarantee the optical performance of the product.

Furthermore, when an attempt is made to increase the magnification ratio in a super-telephoto optical system, the rear group magnification changes significantly between the wide-angle end and the telephoto end, and the aberration fluctuation due to manufacturing error also differs. In high-magnification variable-magnification imaging optical systems, in order to obtain good optical performance over the entire range of variable magnification, the entire system is often composed of four or more groups, and a method of optimizing the movement trajectory of each group is often used. Here, the relationship between the aberration fluctuation sensitivity and the manufacturing error at the wide-angle end and the telephoto end of each group constituting the entire system is not constant, and if the performance of the telephoto end is good in the actual product including the manufacturing error, that is, the wide-angle end. Performance is not always good. As described above, in a super-telephoto and high-magnification ratio variable-magnification imaging optical system, it is difficult to guarantee the performance over the entire variable-magnification range of the product from the viewpoints of both design performance and manufacturing error sensitivity.

The high magnification ratio zoom lens described in Cited Document 1 achieves a high magnification ratio and a sufficient level of aberration correction, but as a means of this, there are many error factors because there are as many as seven groups that move during zooming. .. In particular, the 4th to 6th lens groups have high sensitivity of coma aberration and image plane tilt due to tilt and shift with respect to the optical axis, and the expected value of performance in consideration of manufacturing error is low, which is a required level in recent years. Not satisfied. Since the sensitivity of each group to various aberrations differs depending on the group, focal length range, and type of eccentricity, it is difficult to achieve good performance over the entire range of magnification even when eccentricity adjustment is taken into consideration.

The zoom lens described in Cited Document 2 achieves a very high magnification ratio. However, the occurrence of coma aberration is remarkably large especially at the telephoto end of the first lens group alone. Since the first lens group has a large diameter and is heavy, and the amount of movement due to scaling is large, it is difficult to suppress the fluctuation of the eccentricity of the first lens group at the telephoto end, and eccentric coma aberration occurs at the telephoto end. It's easy to do. Eccentric coma causes flare in a uniform direction over the entire screen, which significantly deteriorates imaging performance. Therefore, it is difficult to guarantee the imaging performance at the time of manufacture with the zoom lens described in the document.

The present invention has been made in view of such a situation, is small in size, has good workability at the time of manufacturing, can adjust optical performance, and has good optical performance and anti-vibration performance in the entire range of magnification change. It is an object of the present invention to provide a variable magnification imaging optical system having a vibration isolation function having a high variable magnification ratio including a super-telephoto range.

The first invention for solving the above-mentioned problems is to obtain a first lens group G1 having a positive refractive force, a second lens group G2 having a negative refractive force, and a negative refractive force in order from the object side. It is composed of a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a positive refractive power, and a sixth lens group G6 having a negative refractive power. The aperture aperture S is arranged inside or near the fourth lens group G4, and when scaling from the wide-angle end to the telephoto end, the air spacing between the lens groups changes, and the first lens group G1 is on the object side. The second lens group G2 moves to the image side, the third lens group G3 does not move with respect to the image plane during scaling and focusing, and the third lens group G3 moves in order from the object side. It is composed of a third lens group front group G3a having a positive refractive force and a third lens group rear group G3b having a negative refractive force, and vibration isolation is provided by shifting the G3b group in a direction orthogonal to the optical axis. The first lens group G1 is composed of a junction lens composed of a negative lens L1 and a positive lens L2, and a positive lens L3, and is characterized by satisfying the following conditional expression (1). ) 0.30 <f1 / ft <0.55
(2) 8.2 << | ft / f2 | <10.7
(3) -0.85 <{(n2-n1) / r2} / {(n1-1) / r1} <-0.50
(4) 0.50 <r3 / bf1 <2.00
fi: Synthetic focal length of the i-th lens group ft: Synthetic focal length of the entire optical system in the telephoto end and infinite focus state ri: Radius of curvature of the i-th optical surface of the optical system from the object side ni: Optical The d-line (focal length 587.56 nm) refractive index of the medium between the i-th and i + 1-th optical planes from the object side of the system bf1: The negative lens L

The second invention is the variable magnification imaging optical system according to the first invention, which satisfies the following conditional expression (5) 0.30 <ht / r2 <0.45.
ht: Radius of the entrance pupil at the telephoto end and in the in-focus state at infinity ri: Radius of curvature of the i-th optical surface from the object side of the optical system

The third invention is the variable magnification imaging optical system according to the first invention or the second invention, which satisfies the following conditional expression (6) 8.50 <ft / fw.
(7) 0.55 <LT / ft <0.85
ft: Synthetic focal length of the entire optical system in the telephoto end and infinity focus state fw: Synthetic focal length of the entire optical system in the wide-angle end and infinity focus state LT: Optical in the telephoto end and infinity focus state The length from the optical plane on the most object side of the system to the image

A fourth aspect of the invention is the variable magnification imaging according to any one of the first to third inventions, wherein the second lens group G2 has at least one positive lens and one negative lens. Optical system

The fifth aspect of the invention is the first to fourth inventions, characterized in that the group spacing between the fifth lens group G5 and the sixth lens group G6 changes when focusing from an infinite distance to a short distance. The variable magnification imaging optical system described in any of the above.

The sixth invention is the variable magnification imaging optical system (8) 2.0 <β6 <4.0 according to the fifth invention, which satisfies the following conditional expression.
β6: Imaging magnification of the sixth lens group G6 at the telephoto end and in infinity in focus.

The seventh invention is the variable magnification imaging optical system according to the fifth invention or the sixth invention, wherein the sixth lens group G6 moves when focusing from an infinite distance to a short distance.

The eighth invention is the variable magnification imaging optical system according to any one of the first to seventh inventions, which is characterized by satisfying the following conditional expression (9) 2.5 <f3 / f2 <. 6.0
(10) 1.00 << | f3a / f3b | <2.50
fi: Composite focal length of the i-th lens group f3a: Composite focal length of the third lens group front group G3a f3b: Composite focal length of the third lens group rear group G3b group

The ninth invention is the variable magnification imaging optical system (11) -1.50 <β3b <− according to any one of the first invention to the eighth invention, which is characterized by satisfying the following conditional expression. 0.50
(12) 0.85 <f2 / f3b <2.00
β3b: Imaging magnification fi of the third lens group rear group G3b at the telephoto end and infinite focus state: synthetic focal length f3b of the i-th lens group: synthetic focal length of the third lens group rear group G3b group

INDUSTRIAL APPLICABILITY The present invention has a high-magnification ratio anti-vibration function including a super-telephoto range, which is compact, has good workability at the time of manufacture, and can adjust optical performance, and has good optical performance and anti-vibration performance over the entire range of scaling. It is possible to provide a variable magnification imaging optical system equipped with the above.

It is a lens block diagram which concerns on Example 1 of the variable magnification imaging optical system provided with the vibration isolation function of this invention. FIG. 5 is a longitudinal aberration diagram at the wide-angle end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the first embodiment. It is a longitudinal aberration diagram at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 1 at the time of focusing at a finite long distance. It is a longitudinal aberration diagram at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 1 at the time of finite short-distance focusing. FIG. 5 is a lateral aberration diagram at the wide-angle end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the first embodiment. FIG. 5 is a lateral aberration diagram at a wide-angle end and a finite long-distance focusing of a variable-magnification imaging optical system having an anti-vibration function according to the first embodiment. FIG. 5 is a lateral aberration diagram at a wide-angle end and a finite short-distance focusing of a variable-magnification imaging optical system having a vibration-proof function according to the first embodiment. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 1 and infinity focusing. It is a longitudinal aberration diagram at the time of infinity focusing in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 1. FIG. 5 is a longitudinal aberration diagram at the time of focusing at a finite long distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the first embodiment. FIG. 5 is a longitudinal aberration diagram at the time of focusing at a finite short distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the first embodiment. It is a lateral aberration diagram at the time of infinity focusing in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 1. FIG. FIG. 5 is a lateral aberration diagram at the time of focusing at a finite long distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the first embodiment. FIG. 5 is a lateral aberration diagram at the time of focusing at a finite short distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the first embodiment. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at infinity in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 1. It is a longitudinal aberration diagram at the telephoto end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the first embodiment. It is a longitudinal aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 1 at the time of focusing at a finite long distance. It is a longitudinal aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 1 at the time of finite short-distance focusing. FIG. 5 is a lateral aberration diagram at the telephoto end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the first embodiment. It is a lateral aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 1 at the time of focusing at a finite long distance. It is a lateral aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 1 at the time of finite short-distance focusing. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 1 and when the optical axis is tilted at infinity. It is a lens block diagram which concerns on Example 2 of the variable magnification imaging optical system provided with the vibration isolation function of this invention. It is a longitudinal aberration diagram at the wide-angle end, infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of Example 2. It is a longitudinal aberration diagram at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 2 at the time of focusing at a finite long distance. It is a longitudinal aberration diagram at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 2 at the time of finite short-distance focusing. FIG. 5 is a lateral aberration diagram at the wide-angle end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the second embodiment. FIG. 5 is a lateral aberration diagram at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of the second embodiment at a finite long-distance focusing. FIG. 5 is a lateral aberration diagram at a wide-angle end and a finite short-distance focusing of a variable-magnification imaging optical system having an anti-vibration function according to the second embodiment. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 2 and infinity focusing. It is a longitudinal aberration diagram at the time of infinity focusing in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the second embodiment. FIG. 5 is a longitudinal aberration diagram at the time of focusing at a finite long distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the second embodiment. FIG. 3 is a longitudinal aberration diagram at the time of focusing at a finite short distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the second embodiment. It is a lateral aberration diagram at the time of infinity focusing in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 2. FIG. FIG. 5 is a lateral aberration diagram at the time of focusing at a finite long distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the second embodiment. FIG. 5 is a lateral aberration diagram at the time of focusing at a finite short distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the second embodiment. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at infinity in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the second embodiment. It is a longitudinal aberration diagram at the telephoto end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the second embodiment. It is a longitudinal aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of the second embodiment, and at the time of focusing at a finite long distance. It is a longitudinal aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of the second embodiment, and at the time of finite short-distance focusing. FIG. 5 is a lateral aberration diagram at the telephoto end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the second embodiment. It is a lateral aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 2 at the time of focusing at a finite long distance. It is a lateral aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 2 at the time of finite short-distance focusing. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of the second embodiment and infinity. It is a lens block diagram which concerns on Example 3 of the variable magnification imaging optical system provided with the vibration isolation function of this invention. FIG. 3 is a longitudinal aberration diagram at the wide-angle end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the third embodiment. FIG. 3 is a longitudinal aberration diagram at a wide-angle end and a finite long-distance focusing of a variable-magnification imaging optical system having an anti-vibration function according to the third embodiment. FIG. 3 is a longitudinal aberration diagram at a wide-angle end and a finite short-distance focusing of a variable-magnification imaging optical system having an anti-vibration function according to the third embodiment. FIG. 3 is a lateral aberration diagram at the wide-angle end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the third embodiment. It is a lateral aberration diagram at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 3 at the time of finite long-distance focusing. FIG. 3 is a lateral aberration diagram at a wide-angle end and a finite short-distance focusing of a variable-magnification imaging optical system having a vibration-proof function according to the third embodiment. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 3 and infinity focusing. It is a longitudinal aberration diagram at the time of infinity focusing in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the third embodiment. FIG. 3 is a longitudinal aberration diagram at the time of focusing at a finite long distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the third embodiment. FIG. 3 is a longitudinal aberration diagram at the time of focusing at a finite short distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the third embodiment. It is a lateral aberration diagram at the time of infinity focusing in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 3. FIG. FIG. 3 is a lateral aberration diagram at the time of focusing at a finite long distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the third embodiment. FIG. 3 is a lateral aberration diagram at the time of focusing at a finite short distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the third embodiment. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at infinity in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the third embodiment. It is a longitudinal aberration diagram at the telephoto end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the third embodiment. It is a longitudinal aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 3 at the time of focusing at a finite long distance. It is a longitudinal aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 3 at the time of finite short-distance focusing. FIG. 3 is a lateral aberration diagram at the telephoto end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the third embodiment. It is a lateral aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 3 at the time of focusing at a finite long distance. It is a lateral aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 3 at the time of finite short-distance focusing. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 3 and infinity focusing. It is a lens block diagram which concerns on Example 4 of the variable magnification imaging optical system provided with the vibration isolation function of this invention. It is a longitudinal aberration diagram at the wide-angle end, infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of Example 4. It is a longitudinal aberration diagram at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 4, and at the time of focusing at a finite long distance. FIG. 5 is a longitudinal aberration diagram at a wide-angle end and a finite short-distance focusing of a variable-magnification imaging optical system having an anti-vibration function according to the fourth embodiment. FIG. 5 is a lateral aberration diagram at the wide-angle end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the fourth embodiment. FIG. 5 is a lateral aberration diagram at a wide-angle end and a finite long-distance focusing of a variable-magnification imaging optical system having an anti-vibration function according to the fourth embodiment. FIG. 5 is a lateral aberration diagram at a wide-angle end and a finite short-distance focusing of a variable-magnification imaging optical system having an anti-vibration function according to the fourth embodiment. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 4 and infinity focusing. It is a longitudinal aberration diagram at the time of infinity focusing in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 4. FIG. 5 is a longitudinal aberration diagram at the time of focusing at a finite long distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the fourth embodiment. It is a longitudinal aberration diagram at the time of the middle and finite short-distance focusing of the variable magnification imaging optical system provided with the vibration isolation function of Example 4. It is a lateral aberration diagram at the time of infinity focusing in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 4. FIG. FIG. 5 is a lateral aberration diagram at the time of focusing at a finite long distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the fourth embodiment. FIG. 5 is a lateral aberration diagram at the time of focusing at a finite short distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the fourth embodiment. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at infinity in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the fourth embodiment. It is a longitudinal aberration diagram at the telephoto end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the fourth embodiment. It is a longitudinal aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 4, and at the time of focusing at a finite long distance. It is a longitudinal aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 4, and at the time of finite short-distance focusing. FIG. 5 is a lateral aberration diagram at the telephoto end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the fourth embodiment. It is a lateral aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 4, and at the time of focusing at a finite long distance. It is a lateral aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 4, and at the time of finite short-distance focusing. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 4 and infinity focusing. It is a lens block diagram which concerns on Example 5 of the variable magnification imaging optical system provided with the vibration isolation function of this invention. FIG. 5 is a longitudinal aberration diagram at the wide-angle end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the fifth embodiment. FIG. 5 is a longitudinal aberration diagram at a wide-angle end and a finite long-distance focusing of a variable-magnification imaging optical system having an anti-vibration function according to the fifth embodiment. FIG. 5 is a longitudinal aberration diagram at a wide-angle end and a finite short-distance focusing of a variable-magnification imaging optical system having an anti-vibration function according to the fifth embodiment. FIG. 5 is a lateral aberration diagram at the wide-angle end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the fifth embodiment. FIG. 5 is a lateral aberration diagram at a wide-angle end and a finite long-distance focusing of a variable-magnification imaging optical system having an anti-vibration function according to the fifth embodiment. FIG. 5 is a lateral aberration diagram at a wide-angle end and a finite short-distance focusing of a variable-magnification imaging optical system having an anti-vibration function according to the fifth embodiment. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 5 and infinity focusing. It is a longitudinal aberration diagram at the time of infinity focusing in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 5. FIG. 5 is a longitudinal aberration diagram at the time of focusing at a finite long distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the fifth embodiment. FIG. 5 is a longitudinal aberration diagram at the time of focusing at a finite short distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the fifth embodiment. It is a lateral aberration diagram at the time of infinity focusing in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 5. FIG. 5 is a lateral aberration diagram at the time of focusing at a finite long distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the fifth embodiment. FIG. 5 is a lateral aberration diagram at the time of focusing at a finite short distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the fifth embodiment. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at infinity in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 5. FIG. 5 is a longitudinal aberration diagram at the telephoto end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the fifth embodiment. It is a longitudinal aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 5, and at the time of focusing at a finite long distance. It is a longitudinal aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 5, and at the time of finite short-distance focusing. FIG. 5 is a lateral aberration diagram at the telephoto end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the fifth embodiment. It is a lateral aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 5, and at the time of focusing at a finite long distance. It is a lateral aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 5, and at the time of finite short-distance focusing. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 5 and infinity focusing. It is a lens block diagram which concerns on Example 6 of the variable magnification imaging optical system provided with the vibration isolation function of this invention. It is a longitudinal aberration diagram at the wide-angle end, infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of Example 6. FIG. 3 is a longitudinal aberration diagram at a wide-angle end and a finite long-distance focusing of a variable-magnification imaging optical system having an anti-vibration function according to the sixth embodiment. It is a longitudinal aberration diagram at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 6 at the time of finite short-distance focusing. It is a lateral aberration diagram at the wide-angle end, infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of Example 6. It is a lateral aberration diagram at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 6 at the time of focusing at a finite long distance. FIG. 5 is a lateral aberration diagram at a wide-angle end and a finite short-distance focusing of a variable-magnification imaging optical system having an anti-vibration function according to the sixth embodiment. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 6 and infinity focusing. It is a longitudinal aberration diagram at the time of infinity focusing in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 6. FIG. 5 is a longitudinal aberration diagram at the time of focusing at a finite long distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the sixth embodiment. It is a longitudinal aberration diagram at the time of the middle and finite short-distance focusing of the variable magnification imaging optical system provided with the vibration isolation function of Example 6. It is a lateral aberration diagram at the time of infinity focusing in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 6. FIG. 5 is a lateral aberration diagram at the time of focusing at a finite long distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the sixth embodiment. FIG. 5 is a lateral aberration diagram at the time of focusing at a finite short distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the sixth embodiment. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at infinity in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the sixth embodiment. It is a longitudinal aberration diagram at the telephoto end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the sixth embodiment. It is a longitudinal aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 6 at the time of focusing at a finite long distance. It is a longitudinal aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 6 at the time of finite short-distance focusing. It is a lateral aberration diagram at the telephoto end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of Example 6. It is a lateral aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 6 at the time of focusing at a finite long distance. It is a lateral aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 6 at the time of finite short-distance focusing. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 6 and infinity focusing. It is a lens block diagram which concerns on Example 7 of the variable magnification imaging optical system provided with the vibration isolation function of this invention. FIG. 5 is a longitudinal aberration diagram at the wide-angle end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the seventh embodiment. It is a longitudinal aberration diagram at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 7, and at the time of focusing at a finite long distance. FIG. 5 is a longitudinal aberration diagram at a wide-angle end and a finite short-distance focusing of a variable-magnification imaging optical system having an anti-vibration function according to the seventh embodiment. FIG. 5 is a lateral aberration diagram at the wide-angle end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the seventh embodiment. FIG. 5 is a lateral aberration diagram at a wide-angle end and a finite long-distance focusing of a variable-magnification imaging optical system having an anti-vibration function according to the seventh embodiment. FIG. 5 is a lateral aberration diagram at a wide-angle end and a finite short-distance focusing of a variable-magnification imaging optical system having an anti-vibration function according to the seventh embodiment. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 7 and infinity focusing. It is a longitudinal aberration diagram at the time of infinity focusing in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 7. FIG. 5 is a longitudinal aberration diagram at the time of focusing at a finite long distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the seventh embodiment. FIG. 5 is a longitudinal aberration diagram at the time of focusing at a finite short distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the seventh embodiment. It is a lateral aberration diagram at the time of infinity focusing in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 7. FIG. FIG. 5 is a lateral aberration diagram at the time of focusing at a finite long distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the seventh embodiment. FIG. 5 is a lateral aberration diagram at the time of focusing at a finite short distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the seventh embodiment. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at infinity in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 7. It is a longitudinal aberration diagram at the telephoto end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the seventh embodiment. It is a longitudinal aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of the seventh embodiment, and at the time of focusing at a finite long distance. It is a longitudinal aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 7, and at the time of finite short-distance focusing. It is a lateral aberration diagram at the telephoto end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of Example 7. It is a lateral aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 7, and at the time of focusing at a finite long distance. It is a lateral aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 7, and at the time of finite short-distance focusing. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at the telephoto end of the variable magnification imaging optical system having the vibration isolation function according to the seventh embodiment and when the optical axis is tilted at infinity. It is a lens block diagram which concerns on Example 8 of the variable magnification imaging optical system provided with the vibration isolation function of this invention. It is a longitudinal aberration diagram at the wide-angle end, infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of Example 8. It is a longitudinal aberration diagram at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 8 at the time of focusing at a finite long distance. It is a longitudinal aberration diagram at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 8 at the time of finite short-distance focusing. FIG. 5 is a lateral aberration diagram at the wide-angle end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the eighth embodiment. FIG. 5 is a lateral aberration diagram at a wide-angle end and a finite long-distance focusing of a variable-magnification imaging optical system having an anti-vibration function according to the eighth embodiment. FIG. 5 is a lateral aberration diagram at a wide-angle end and a finite short-distance focusing of a variable-magnification imaging optical system having a vibration-proof function according to the eighth embodiment. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at the wide-angle end of the variable magnification imaging optical system provided with the vibration isolation function of Example 8 and infinity focusing. It is a longitudinal aberration diagram at the time of infinity focusing in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 8. FIG. 5 is a longitudinal aberration diagram at the time of focusing at a finite long distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the eighth embodiment. FIG. 5 is a longitudinal aberration diagram at the time of focusing at a finite short distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the eighth embodiment. It is a lateral aberration diagram at the time of infinity focusing in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 8. FIG. 5 is a lateral aberration diagram at the time of focusing at a finite long distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the eighth embodiment. FIG. 5 is a lateral aberration diagram at the time of focusing at a finite short distance in the middle of the variable magnification imaging optical system provided with the vibration isolation function of the eighth embodiment. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at infinity in the middle of the variable magnification imaging optical system provided with the vibration isolation function of Example 8. It is a longitudinal aberration diagram at the telephoto end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of the eighth embodiment. It is a longitudinal aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 8 at the time of focusing at a finite long distance. It is a longitudinal aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 8 at the time of finite short-distance focusing. It is a lateral aberration diagram at the telephoto end and infinity focusing of the variable magnification imaging optical system provided with the vibration isolation function of Example 8. It is a lateral aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 8 at the time of focusing at a finite long distance. It is a lateral aberration diagram at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 8 at the time of finite short-distance focusing. FIG. 5 is a lateral aberration diagram when vibration isolation is performed in a state where the optical axis is tilted by 0.4 degrees at the telephoto end of the variable magnification imaging optical system provided with the vibration isolation function of Example 8 and infinity focusing.

From the object side, the first lens group G1 having a positive refractive force, the second lens group G2 having a negative refractive force, the third lens group G3 having a negative refractive force, and the positive refractive force. It is composed of a fourth lens group G4, a fifth lens group G5 having a positive refractive force, and a sixth lens group G6 having a negative refractive force, and the aperture aperture S is inside or near the fourth lens group G4. When scaling from the wide-angle end to the telephoto end, the air spacing between each lens group changes, the first lens group G1 moves to the object side, and the second lens group G2 moves to the image side. The third lens group G3 moves and does not move with respect to the image plane during scaling and focusing, and the third lens group G3 and the third lens group front group G3a having a positive refractive force in order from the object side. It is composed of a third lens group rear group G3b having a negative refractive force, and vibration isolation is performed by shifting the G3b group in a direction orthogonal to the optical axis, and the first lens group G1 is positive with the negative lens L1. A variable magnification imaging optical system including a junction lens composed of a lens L2 and a positive lens L3.

In a variable magnification imaging optical system including a region having a long focal length, the amount of movement of each group tends to be large. Further, even in a variable magnification imaging optical system having a large magnification ratio, the amount of movement of each group tends to be large as well.

In a variable magnification imaging optical system that includes a variable magnification region with a long focal length with respect to the diagonal length of the image sensor, the first lens group G1 has a positive refractive power and the second lens group G2 has a negative power in order to shorten the total length. It is preferable to adopt a positive-preceding type configuration with a refractive power, and shortening the total length of the optical system at the telephoto end with respect to the focal length contributes to miniaturization of the optical system and reduction of the amount of movement of each lens group.

Next, when scaling from the wide-angle end to the telephoto end, at least one of the first lens group G1 and the second lens group G2 is moved so as to widen the distance between the first lens group G1 and the second lens group G2. As a result, the image magnification of the second lens group G2 becomes large, and the focal length of the entire optical system can be extended.

In addition, if the amount of movement of the first lens group, which tends to have a large diameter and increase in weight, becomes large, a large burden is placed on the movement mechanism, an eccentricity error of the first lens group is likely to occur, and further, a scaling operation is also possible. It is not preferable because a large force is required.

On the other hand, if the amount of movement of the first lens group G1 is suppressed and the amount of movement of the second lens group G2 is increased, the total length of the optical system at the wide-angle end becomes large, and vignetting around the screen at the wide-angle end is avoided. In addition, it becomes necessary to set the diameters of the first lens group G1 and the second lens group G2 to be large, which increases the weight of the entire optical system.

Therefore, in the variable magnification imaging optical system of the present invention, in order to achieve both long focus and high magnification, the first lens group G1 is placed on the object side and the second lens is set as the magnification changes from the wide-angle end to the telephoto end. By moving the group G2 to the image side, the movement amount of the first lens group G1 is suppressed, the total length is shortened at the wide-angle end, and the diameters of the first lens group G1 and the second lens group G2 are suppressed accordingly. I am trying.

The third lens group G3 has a negative refractive power like the second lens group G2, and is stationary with respect to the image plane at the time of scaling. This is for vibration isolation, which will be described later.

The 4th lens group G4, the 5th lens group G5, and the 6th lens group G6 have a positive combined refraction force over the entire range of scaling and are responsible for imaging action, while changing the spacing between the groups during scaling. By moving to the object side, each aberration fluctuation such as focal position movement and astigmatism due to the change in the distance between the first lens group G1, the second lens group G2, and the third lens group G3 is corrected. It plays an auxiliary scaling effect to obtain a high scaling factor as a whole system.

In a super-telephoto positive-preceding variable-magnification optical system, the optical light beam on the axis converges and is incident due to the converging action of the first lens group G1 and has a large image-gathering magnification at the telephoto end. By using the whole or part of the lens group with negative refraction as the anti-vibration group, a large image displacement can be obtained while avoiding fluctuations in eccentric coma, and good anti-vibration performance can be obtained at the telephoto end. It is known to be. On the other hand, in order to use it as a vibration isolation group, it is necessary to provide a drive mechanism in this group and connect its control wiring. When connecting the control wiring, it is better that the amount of movement during scaling and focusing of the vibration isolation group is small, and it is most desirable that the vibration isolation group is stationary.

In the present invention, in order to weaken the optical power of the third lens group G3 as a whole and make it stand still at the time of scaling, and to increase the image magnification of the vibration isolation group to secure a sufficient amount of image displacement, the third lens group G3 is composed of a third lens group front group G3a having a positive refractive power and a third lens group rear group G3b having a negative refractive power, and the third lens group rear group G3b is displaced in a direction orthogonal to the optical axis. It is configured to be vibration-proof by making it. By bringing the third lens group front group G3a having a positive refractive power and the third lens group rear group G3b having a negative refractive power close to each other, the refractive power of the entire third lens group G3 is weakened and the third lens group front group. By increasing the image magnification of the third lens group rear group G3b by the converging action of G3a, the image magnification of the third lens group rear group G3b, which is the vibration isolation group, is fixed while the third lens group G3 is fixed at the time of scaling. The size of the lens has been increased, the drive mechanism and control wiring have been installed, and sufficient anti-vibration performance has been achieved.

On the other hand, in recent years, in order to correct the deterioration of the imaging performance of the optical system due to the eccentricity caused by the manufacturing error, the eccentricity adjustment that intentionally generates the eccentricity in a part of the optical system to cancel the aberration in the whole system. Is often done. In particular, by correcting the tilt of the image plane and the eccentric coma aberration that are likely to occur due to eccentricity due to manufacturing errors, the imaging performance of the product can be significantly improved.

In particular, in a high-magnification variable-magnification imaging optical system, the number of movable groups tends to increase in order to ensure design performance over the entire variable-magnification range. That is, since there are many factors that cause manufacturing errors, there is a high need for eccentricity adjustment. Further, since the magnification of each group at the wide-angle end and the telephoto end changes greatly, the amount of fluctuation of various aberrations at the time of eccentricity of each group also changes greatly at the wide-angle end and the telephoto end. In order to achieve sufficiently good image quality over the entire range of magnification and the entire area of the screen, it is desirable to adjust aberrations associated with multiple types of eccentricity at multiple magnification positions.

However, in general, with the eccentricity of a part of an optical system, a plurality of types of aberration fluctuations are generated at a plurality of variable magnification positions.

For example, when an attempt is made to correct the first aberration by adjusting the eccentricity of the first adjustment unit, fluctuations in the second aberration occur together with the first aberration. If the fluctuation of the first aberration occurs when the eccentric adjustment of the second adjusting portion for correcting the fluctuation of the second aberration occurs, the adjustment of the first adjusting portion is required again, and the desired performance is obtained. It takes time and effort to obtain the above, and the assembly cost increases.

In this way, if good performance is to be obtained in the eccentricity adjustment of the variable magnification imaging optical system over the entire range of the variable magnification and the screen, one variable magnification position and one species can be obtained in at least one adjustment unit. The eccentricity adjustment is completed by making a change in the aberration of the optics and ignoring the influence on other scaling positions or other types of aberrations, and finally adjusting this one adjustment part. It is desirable that the optical system be designed so that it does.

Since the second lens group G2 has a large magnification at the telephoto end, the change in the distance between the first lens group G1 and the second lens group G2 has a great influence on the change in the imaging position. Therefore, the image plane can be tilted by causing an asymmetric interval change in the vertical direction of the optical system, that is, by tilting the first lens group G1 or the second lens group G2 around an axis orthogonal to the optical axis. At the wide-angle end, the magnification of the second lens group G2 is low, and the above action is weakened.

On the other hand, in particular, the lens group on the image side of the 4th lens group G4 has a limited amount of movement because the third lens group G3 is fixed, and the magnification of itself and the combined image magnification of the lens group on the image side of itself are limited. Since there is little change, there is little change in the sensitivity of aberration fluctuations at the wide-angle end and the telephoto end. After adjusting the eccentricity of the aberration at the wide-angle end using the lens group after the 4th lens group G4, the image plane tilt adjustment at the telephoto end is performed by tilting the first lens group G1 or the second lens group G2. The performance at the wide-angle end and the telephoto end can be optimally adjusted with as few steps as possible. In particular, by tilting the first lens group G1 which is on the outermost side of the optical system and can be easily removed after assembling the entire system, the performance of the product can be improved with good workability.

However, since the axial luminous flux diameter is large in the first lens group G1, fluctuations in eccentric coma due to tilt are likely to occur. Unless the sensitivity of eccentric coma aberration is sufficiently reduced, the fluctuation cannot be ignored, and sufficient performance cannot be guaranteed after eccentricity adjustment.

First, in order to sufficiently correct spherical aberration, the first lens group G1 is composed of two lens elements having a positive refractive force, and one lens element while suppressing the occurrence of spherical aberration in each element. The negative spherical aberration generated by the positive lens is canceled by arranging the negative lens of. In order to correct axial and chromatic aberration of magnification, which tends to be a problem in the super-telephoto range, it is desirable to use a glass material with as low dispersion as possible for the positive lens of the first lens group G1, and the refractive index of such glass material tends to be low. There is. On the other hand, a sufficiently highly dispersed glass material is desirable for the negative lens in the first lens group G1, and the refractive index of such a glass material tends to be high. Such a combination of refractive indexes is also preferable for correcting spherical aberration.

In addition, since glass materials with a low refractive index and low dispersion tend to have a high degree of wear and are easily scratched, practically, the negative lens should be placed closest to the object so that the optical surface on the object side is not scratched when used. Is desirable. Since negative lenses and positive lenses arranged in close proximity are prone to eccentric coma due to their relative eccentricity, it is desirable to improve the assembly accuracy as a junction lens. Therefore, it is desirable that the first lens group G1 is composed of a junction lens composed of a negative lens L1 and a positive lens L2 and a positive lens L3.

In the first lens group G1 having such a configuration, the junction surface R2 of the negative lens L1 and the positive lens L2 has a convex shape toward the object side and has a relatively strong luminous flux divergence action, and is an outer coma off the axis. Generates aberrations. If the residual amount of coma aberration is large as a whole of the junction lens of the negative lens L1 and the positive lens L2, the eccentric coma aberration that occurs in the whole system when the first lens group G1 is tilted tends to be large. The diameter of the axial luminous flux passing through the first lens group becomes large, and the influence of this eccentric coma becomes more remarkable at the telephoto end where the image magnification of the composite system after the second lens group G2 is large. Therefore, the coma aberration generated on the junction surface R2 must be corrected in the first lens group G1.

In the present invention, the object side surface R1 of the negative lens L1 is made convex toward the object to increase its curvature, and inward coma is generated on this surface, so that it is generated at the junction surface R2 between the negative lens L1 and the positive lens L2. By configuring the configuration to almost cancel the coma aberration, the coma aberration of the first lens group G1 is corrected, and the occurrence of eccentric coma aberration when the image plane tilt correction at the telephoto end is performed by the tilt of the first lens group G1 is generated. Suppressed.

Even if the coma aberration generated on the object side surface R1 of the negative lens L1 and the junction surface R2 of the negative lens L1 and the positive lens L2 is canceled, if the coma aberration occurs on another surface in the first lens group G1, the first The coma aberration of the lens group G1 remains. In the present invention, the axial marginal ray passing through the image side surface R3 of the positive lens L2 further reduces the angle formed by the surface normal of the image side surface R3 of the positive lens L2, so that spherical aberration and coma aberration are generated in the vicinity of the axis. It was configured to suppress.

Further, in order to suppress the occurrence of coma aberration in the positive lens L3, the deviation angle of the axial marginal light rays before and after passing through the object-side lens surface R4 of the positive lens L3 and the image-side lens surface R5 of the positive lens L3 are passed. It is desirable to set the deviation angles of the marginal rays on the front and back axes to be approximately equal.

It is configured to satisfy the following conditional expression.
(1) 0.30 <f1 / ft <0.55
(2) 8.2 << | ft / f2 | <10.7
(3) -0.85 <{(n2-n1) / r2} / {(n1-1) / r1} <-0.50
(4) 0.50 <r3 / bf1 <2.00
fi: Synthetic focal distance of the i-th lens group ft: Synthetic focal distance of the entire optical system in the telephoto end and infinite focus state ri: Radius of curvature of the i-th optical surface of the optical system from the object side ni: Optical The d-line (wavelength 587.56 nm) refractive index bf1: of the medium between the i-th and i + 1-th optical planes from the object side of the system, which is the most image-side of the junction lens composed of the negative lens L1 and the positive lens L2. Distance from the surface apex to the image side focal point of the junction lens

The conditional equation (1) to be satisfied by the variable magnification imaging optical system of the present invention defines the relationship between the combined focal length of the entire system at the telephoto end and the combined focal length of the first lens group, and shortens the total length of the optical system and mirrors. It shows the desirable range for weight reduction of the cylinder.

When the focal length of the first lens group G1 becomes longer than the combined focal length of the entire system beyond the upper limit of the conditional equation (1), the total length of the optical system at the telephoto end becomes longer and the amount of movement of the first lens group G1 increases. The increase causes a load on the moving mechanism, and eccentricity of the first lens group G1 is likely to occur. Therefore, the strength of the lens barrel is required, the weight of the lens barrel increases, and the scaling operation becomes difficult.

When the focal length of the first lens group G1 is shorter than the lower limit of the conditional equation (1) with respect to the composite focal length of the entire system, the image magnification of the composite system after the second lens group G2 at the telephoto end becomes higher. In addition to making it difficult to correct various aberrations such as axial chromatic aberration at the telephoto end, it is difficult to ensure product performance due to large aberration fluctuations with respect to manufacturing errors in the first lens group G1.

Regarding the conditional expression (1), the lower limit value is preferably set to 0.34, the lower limit value is set to 0.37, the upper limit value is set to 0.52, and the upper limit value is set to 0.49. By prescribing, the above-mentioned effect can be further ensured.

The conditional equation (2) to be satisfied in the variable magnification imaging optical system of the present invention defines the relationship between the combined focal length of the entire system at the telephoto end and the combined focal length of the second lens group G2, and defines the first lens group G1 and the combined focal length. It shows a desirable range regarding the reduction of the movement amount of the 2nd lens group G2.

When the negative refractive power of the second lens group G2 becomes stronger than the upper limit of the conditional equation (2), the occurrence of chromatic aberration, spherical aberration, etc. generated in the second lens group G2 becomes large, and the aberration fluctuation at the time of scaling increases. It tends to grow.

When the negative refractive power of the second lens group G2 becomes weaker than the lower limit of the conditional equation (2), the amount of change in the distance between the first lens group G1 and the second lens group G2 required for scaling becomes too large, and the first lens group G2 becomes the first. The amount of movement of the lens group G1 and the second lens group G2 increases.

With regard to the conditional expression (2), preferably, the lower limit value is set to 8.3 and the upper limit value is set to 10.00, so that the above-mentioned effect can be further ensured.

The conditional equations (3) and (4) to be satisfied in the variable magnification imaging optical system of the present invention define the radius of curvature of the negative lens L1 and the positive lens L2 constituting the first lens group and the refractive index of the glass material. It shows a preferable range for correcting the coma of one lens group satisfactorily and, by extension, tilting the first lens group to correct the tilt of the image plane due to the manufacturing error at the telephoto end.

If the upper limit of the conditional equation (3) is exceeded, the deviation angle of the axial marginal ray before and after passing through the negative lens L1 becomes small, and the negative lens L1 causes spherical aberration, axial aberration and chromatic aberration of magnification of the first lens group G1. Since it does not contribute to the correction, appropriate optical performance cannot be obtained for the first lens group G1 as a whole.

Below the lower limit of the conditional equation (3), the coma aberration generated on the object side surface R1 of the negative lens L1 becomes small, and the sum of the coma aberrations generated by the junction surface R2 of the negative lens L1 and the positive lens L2 can be canceled. It is difficult to suppress the eccentric coma aberration that occurs as a side effect when the first lens group G1 is tilted to correct the tilt of the image plane due to the manufacturing error at the telephoto end.

In the conditional expression (3), preferably, the lower limit value is set to -0.80 and the upper limit value is set to -0.65, so that the above-mentioned effect can be further ensured.

If the upper limit or the lower limit of the conditional equation (4) is exceeded, the deviation angle of the axial marginal light before and after passing through the image side surface R3 of the positive lens L2 becomes large, causing spherical aberration and coma aberration, and the first lens group G1. It is difficult to suppress the eccentric coma aberration that occurs as a side effect when tilting the lens to correct the tilt of the image plane due to the manufacturing error at the telephoto end.

Regarding the conditional expression (4), the lower limit value is preferably set to 0.60, the lower limit value is set to 0.67, the upper limit value is set to 1.95, and the upper limit value is set to 1.92. By prescribing, the above-mentioned effect can be made more certain.

Further, the present invention is configured to satisfy the following conditional expression.
(5) 0.30 <ht / r2 <0.45
however,
ht: Radius of the entrance pupil at the telephoto end and in the in-focus state at infinity ri: Radius of curvature of the i-th optical surface from the object side of the optical system

Conditional expression (5) defines the ratio of the radius of curvature of the junction surface R2 of the negative lens L1 and the positive lens L2 to the radius of the entrance pupil at the telephoto end, and shows the conditions under which the configuration of the present invention is particularly effective. be.

When the radius of the incident pupil becomes smaller than the lower limit of the conditional equation (5), the coma aberration generated at the junction surface R2 of the negative lens L1 and the positive lens L2 becomes smaller in the first place, and the eccentricity accompanying the tilt of the first lens group G1 becomes smaller. Fluctuations in coma aberration are not a serious problem, but the effect of correcting spherical aberration and axial and magnification chromatic aberrations due to the junction surface R2 of the negative lens L1 and the positive lens L2 cannot be obtained, so the telephoto end where the incident pupil diameter is particularly large. In, it becomes difficult to correct the aberration of the whole system, or it becomes difficult to shorten the total optical length at the telephoto end.

When the radius of the entrance pupil becomes larger than the upper limit of the conditional equation (5) and approaches the radius of curvature, the coma aberration generated at the junction surface R2 of the negative lens L1 and the positive lens L2 becomes too large, and the entire optical system is used in the first place. Even the correction is difficult, and the performance of the optical system is significantly reduced.

In the conditional expression (5), preferably, the lower limit value is set to 0.32 and the upper limit value is set to 0.40, so that the above-mentioned effect can be further ensured.

Further, the present invention is configured to satisfy the following conditional expression.
(6) 8.50 <ft / fw
(7) 0.55 <LT / ft <0.85
however,
ft: Synthetic focal length of the entire optical system in the telephoto end and infinity focus state fw: Synthetic focal length of the entire optical system in the wide-angle end and infinity focus state LT: In the telephoto end and infinity focus state The length from the optical surface on the most object side of the optical system to the image

Conditional expression (6) defines the scaling ratio to be aimed at in the variable magnification imaging optical system of the optical system of the present invention.

The conditional expression (6) should belong to the specification, but the problem to be solved in the present invention becomes more remarkable as the scaling ratio is larger, and is a precondition for the configuration of the present invention. Is. If the ratio is below the lower limit of the conditional expression (6), the desired scaling ratio cannot be achieved, but the problem to be solved by the present invention is also greatly alleviated.

It should be noted that, preferably, by defining the lower limit value of the conditional expression (6) at 9.0, the above-mentioned effect can be further ensured.

The conditional expression (7) defines the total length of the optical system to be aimed at by the variable magnification imaging optical system of the optical system of the present invention.

Although this conditional equation (7) belongs to the specification, an optical system based on such a methodology can be achieved even if the low image height portion is enlarged if the angle of view in the super-telephoto range is simply achieved. The total length of the optical system tends to be longer than the maximum image height, and the entire lens barrel also becomes large, which goes against the object of the present invention.

The desired optical performance can be achieved by satisfying this conditional expression (7).

If the upper limit of the conditional expression (7) is exceeded, the total length of the optical system becomes too long and the weight of the lens barrel becomes excessive.

On the other hand, if the lower limit of the conditional expression (7) is exceeded, the aberration fluctuation sensitivity with respect to the error of the optical system becomes too large, and the sensitivity of the eccentricity adjustment group also becomes high, so that the tolerance for the adjustment error becomes low. Even in consideration of the above, the expected value of product performance is too low.

In the conditional expression (7), preferably, the lower limit value is set to 0.60 and the upper limit value is set to 0.83, so that the above-mentioned effect can be further ensured.

Further, in the variable magnification imaging optical system of the present invention, the second lens group G2 has at least one positive lens and one negative lens.

When the chromatic aberration ratio of the optical system is increased, the image magnification of the second lens group G2 changes greatly due to the chromatic aberration from the wide-angle end to the telephoto end, and the image magnification of the second lens group G2 changes. Since the height of the axial marginal ray or the off-axis main ray passing through the two lens group G2 changes greatly, various factors such as axial chromatic aberration, chromatic aberration of magnification, coma, and astigmatism generated by the action of the second lens group G2. Fluctuations due to chromatic aberration are likely to occur.

Therefore, in order to suppress fluctuations in these various aberrations due to scaling, the second lens group G2 is configured to include at least one positive lens and one negative lens, and the aberration as a single second lens group. It is desirable to suppress the occurrence.

Further, the present invention has a configuration in which the group spacing of the fifth lens group G5 and the sixth lens group G6 is converted when focusing from an infinite distance to a short distance.

Since the image magnification of the sixth lens group G6 is increased at the telephoto end due to the shortening of the total length, the sensitivity of the position change of the imaging point to the change of the distance between the fifth lens group G5 and the sixth lens group G6 is high. Further, since the fifth lens group G5 to the sixth lens group G6 are located relatively on the image side of the optical system, the passing light flux is sufficiently converged and the outer diameter thereof can be reduced. Therefore, by moving any of the 5th lens group G5 to the 6th lens group G6 in the optical axis direction to change the interval, and focusing from infinity to a short distance, the focusing group is performed. It can reduce the amount of movement and weight of the lens and contribute to quick focusing.

Further, the present invention is configured to satisfy the following conditional expression.
(8) 2.0 <β6 <4.0
however,
β6: Imaging magnification of the 6th lens group G6 at the telephoto end and in infinity in focus

The conditional expression (8) defines the image magnification of the sixth lens group G6, and indicates a preferable range with respect to the amount of movement of the focusing group when focusing at a short distance.

If it falls below the lower limit of the conditional expression (8), the magnification of the sixth lens group G6 becomes too small, the amount of movement of the focusing group at the time of focusing becomes too large, and the total length of the optical system becomes long, so that the product is compact. Inhibits the formation.

If the upper limit of the conditional expression (8) is exceeded, the magnification of the sixth lens group G6 becomes too large, a very high level of position accuracy of the in-focus group is required, and the aberration generated in the previous group is enlarged. Therefore, it becomes difficult to correct the aberration, and the deterioration of the imaging performance due to the manufacturing error tends to be large.

In the conditional expression (8), preferably, the lower limit value is set to 2.3 and the upper limit value is set to 3.5, so that the above-mentioned effect can be further ensured.

Further, the variable magnification imaging optical system of the present invention has a configuration in which the sixth lens group G6 moves when focusing from an infinite distance to a short distance.

In the sixth lens group G6, the on-axis paraxial ray height becomes low due to the converging action of the fifth lens group G5 having a positive refractive power, and even if eccentricity occurs due to a manufacturing error, eccentric coma aberration is unlikely to occur. In order to move the lens group both at the time of scaling and at the time of focusing, the mechanism becomes complicated and the cause of error increases. Therefore, it is preferable to move the sixth lens group having low aberration sensitivity at the time of focusing.

Further, the present invention is configured to satisfy the following conditional expression.
(9) 2.50 <f3 / f2 <6.00
(10) 1.00 << | f3a / f3b | <2.50
however,
fi: Synthetic focal length of the i-th lens group f3a: Synthetic focal length of the third lens group front group G3a f3b: Synthetic focal length of the third lens group rear group G3b

As described above, the third lens group G3 is stationary at the time of scaling. For this purpose, it is preferable to weaken the refractive power of the third lens group G3 as a whole so that the occurrence of aberrations is reduced, because the fluctuations due to the scaling of various aberrations caused by the third lens group G3 can be reduced.

The conditional expression (9) defines the ratio of the focal lengths of the third lens group G3 and the second lens group G2, and shows a preferable range for making the entire third lens group G3 stationary at the time of scaling.

If the refractive power of the third lens group G3 becomes stronger below the lower limit of the conditional expression (9), it becomes difficult to suppress the occurrence of aberration in the third lens group G3, and the change in optical performance due to scaling becomes large. It ends up.

When the upper limit of the conditional equation (9) is exceeded and the refractive power of the third lens group G3 becomes weaker, the refractive power of the second lens group G2 becomes stronger in order to maintain the negative refractive power, and the negative refractive power becomes the optical system. It is difficult to shorten the total length of the optical system because the retrofocus type refractive power arrangement becomes stronger as it shifts toward the object.

With regard to the conditional expression (9), preferably, the lower limit value is set to 2.8 and the upper limit value is set to 5.8, so that the above-mentioned effect can be further ensured.

Conditional expression (10) defines the ratio of the refractive powers of the third lens group front group G3a and the third lens group rear group G3b in the third lens group G3, and the third lens group G3 is fixed at the time of scaling. The rear group G3b of the three lens groups shows a preferable range in order to effectively function as the vibration isolation group.

If the negative refractive power of the rear group G3b of the third lens group becomes stronger than the upper limit of the conditional expression (10), it becomes difficult to suppress the refractive power of the entire third lens group G3, and aberration fluctuation occurs at the time of scaling. .. Further, the variation of astigmatism and coma generated when the rear group G3b of the third lens group is shifted in the direction orthogonal to the optical axis becomes large, and effective anti-vibration performance cannot be obtained.

When the negative refractive power of the rear group G3b of the third lens group becomes weaker below the lower limit of the conditional equation (10), a lateral image generated when the rear group G3b of the third lens group is shifted in the direction orthogonal to the optical axis. Since the displacement is small, effective anti-vibration performance cannot be obtained. Alternatively, the required shift amount of the rear group G3b of the third lens group becomes large, and the lens barrel becomes large in the radial direction.

Regarding the conditional expression (10), the lower limit is preferably 1.1, the lower limit is 1.3, the upper limit is 1.9, and the upper limit is 1.65. By prescribing, the above-mentioned effect can be made more certain.

Further, the present invention is configured to satisfy the following conditional expression.
(11) -1.50 <β3b <-0.50
(12) 0.85 <f2 / f3b <2.00
however,
β3b: Imaging magnification of the 3b group at the telephoto end and in focus at infinity fi: Composite focal length of the i-th lens group f3b: Composite focal length of the rear group G3b of the third lens group

In order to suppress the refractive power of the third lens group G3 as a whole and to increase the amount of displacement of the image of the third lens group rear group G3b used for vibration isolation with respect to the shift in the direction orthogonal to the optical axis, the third lens group rear group It is necessary to give G3b a certain level of refractive power or more.

The conditional expression (11) defines the image magnification at the telephoto end of the rear group G3b of the third lens group, and shows a preferable range when the rear group G3b of the third lens group is used for vibration isolation.

When the absolute value of the image magnification of the rear group G3b of the third lens group becomes smaller than the upper limit of the conditional equation (11), the amount of lateral image displacement due to the shift of the rear group G3b of the third lens group in the direction orthogonal to the optical axis Is small, so effective anti-vibration performance cannot be obtained. Alternatively, the required shift amount of the rear group G3b of the third lens group becomes large, and the lens barrel becomes large in the radial direction.

When the absolute value of the imaging magnification of the rear group G3b of the third lens group becomes larger than the lower limit of the conditional expression (11), the amount of lateral image displacement due to the shift of the rear group G3b of the third lens group in the direction perpendicular to the optical axis is large. Is too large, and a very high resolution of the position control of the rear group G3b of the third lens group is required, and as a result, the anti-vibration performance is deteriorated.

In the conditional expression (11), preferably, the lower limit value is set to -1.30 and the upper limit value is set to -0.65, so that the above-mentioned effect can be further ensured.

Next, the conditional expression (12) defines the focal length of the rear group G3b of the third lens group with respect to the second lens group G2, and shows a preferable range for using the rear group G3b of the third lens group for vibration isolation. be.

When the refractive power of the rear group G3b of the third lens group becomes stronger than the upper limit of the conditional equation (12), the amount of lateral image displacement due to the shift of the rear group G3b of the third lens group in the direction orthogonal to the optical axis becomes too large. Therefore, a very high resolution for position control of the rear group G3b of the third lens group is required. As a result, the anti-vibration performance deteriorates.

When the refractive power of the rear group G3b of the third lens group becomes weaker below the lower limit of the conditional equation (12), the amount of lateral image displacement due to the shift of the rear group G3b of the third lens group in the direction orthogonal to the optical axis becomes smaller. However, effective anti-vibration performance cannot be obtained, or the required shift amount of the rear group G3b of the third lens group becomes large, and the lens barrel becomes large in the radial direction, which is not preferable.

In the conditional expression (12), preferably, the lower limit value is set to 0.95 and the upper limit value is set to 1.50, so that the above-mentioned effect can be further ensured.

Next, the lens configuration and specific numerical data of each embodiment of the variable magnification imaging optical system having the vibration isolation function of the present invention will be described. In the following description, the lens configuration will be described in order from the object side to the image side.

In [plane data], the surface number is the number of the lens surface or aperture stop S counted from the object side, r is the refractive index of each surface, d is the distance between each surface, and nd is the d line (wavelength λ = 587.56 nm). Refractive index with respect to, νd indicates the Abbe number with respect to the d line. BF represents back focus.

The numbered surface (aperture) indicates that the aperture diaphragm S is located at that position. ∞ (infinity) is entered for the radius of curvature for a plane or aperture stop.

[Various data] shows values such as focal length.

[Variable interval data] shows the values of the variable interval and the BF (back focus) in each shooting distance state.

[Lens group data] shows the lens surface number on the most object side constituting each lens group and the combined focal length of the entire lens group.

In all the following specification values, the focal length f, the radius of curvature r, the lens surface spacing d, and other length units are described in millimeters (mm) unless otherwise specified, but optics. The system is not limited to this because the same optical performance can be obtained in both proportional expansion and proportional reduction.

Further, in the aberration diagram corresponding to each embodiment, d, g, and C represent the d-line, g-line, and C-line, respectively, and ΔS and ΔM represent the sagittal image plane and the meridional image plane, respectively.

Further, in the lens configuration diagram shown in FIGS. 1, 23, 45, 67, 89, 111, 133, and 155, S is an aperture diaphragm, I is an image plane, and the alternate long and short dash line passing through the center is an optical axis.

FIG. 1 is a lens configuration diagram of a variable magnification imaging optical system having a vibration isolation function according to a first embodiment of the present invention.

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 negative refractive power, and the fourth lens having a positive refractive power. The group G4, the fifth lens group G5 having a positive refractive power, and the sixth lens group G6 having a negative refractive power are arranged and configured.

The first lens group G1 is composed of a junction lens consisting of a negative meniscus lens L1 having a convex surface facing the object side, a positive meniscus lens L2 having a convex surface facing the object side, and a plano-convex lens L3 having a convex surface facing the object side. It moves from the image side to the object side when scaling from the wide-angle end to the telephoto end.

The second lens group G2 is composed of a junction lens consisting of a biconvex lens L4 and a biconcave lens L5, and a negative meniscus lens L6 with a convex surface facing the object side. Move to.

The third lens group G3 is composed of a third lens group front group G3a having a positive refractive power and a third lens group rear group G3b having a negative refractive power, and is fixed to the image plane at the time of scaling.

The front group G3a of the third lens group is composed of a biconvex lens L7 and a positive meniscus lens L8 with a convex surface facing the object side.

The rear group G3b of the third lens group is composed of a biconcave lens L9, a biconcave lens L10, and a junction lens of the biconvex lens L11, and is driven in a direction orthogonal to the optical axis during vibration isolation.

The fourth lens group G4 includes a biconvex lens G12, a junction lens of a biconvex lens G13 and a biconcave lens G14, a positive meniscus lens L15 having a convex surface facing the object side, and a negative meniscus lens L16 having a convex surface facing the object side. It is composed of a junction lens of a biconvex lens L17 and a negative meniscus lens L18 with a convex surface facing the image side, and moves from the image side to the object side when scaling from the wide-angle end to the telephoto end.

Further, an aperture diaphragm S is provided in the air gap between the biconcave lens G14 in the fourth lens group G4 and the positive meniscus lens L15.

The fifth lens group G5 is composed of a negative meniscus lens L19 having a convex surface facing the object side, a biconvex lens L20, and a biconvex lens L21, and moves from the image side to the object side when scaling from the wide-angle end to the telephoto end. ..

The sixth lens group G6 is composed of a positive meniscus lens L22 with a convex surface facing the image side, a biconcave lens L23, and a junction lens of a biconcave lens L24 and a biconvex lens L25. It moves from the side to the telephoto side, and moves from the object side to the image side when focusing from infinity to a short distance.

Subsequently, the specification values of the variable magnification imaging optical system according to the first embodiment are shown below.
Numerical Example 1
Unit: mm
[Surface data]
Face number rd nd vd
1 191.4478 3.0000 1.87071 40.73
2 113.3602 10.0505 1.49700 81.61
3 1000.0000 0.1500
4 125.6151 10.1084 1.43700 95.10
5 ∞ d5
6 133.4879 4.4571 1.80518 25.46
7 -498.8095 1.5000 1.87071 40.73
8 74.0328 3.2320
9 457.8311 1.5000 1.87071 40.73
10 68.7453 d10
11 96.7106 3.6537 1.60342 38.01
12 -537.0800 7.8844
13 51.0188 3.2604 1.51742 52.15
14 123.3817 4.8080
15 -490.1727 0.9000 1.75700 47.82
16 63.0806 4.1944
17 -48.5730 1.0000 1.61997 63.88
18 88.4615 3.1979 1.85478 24.80
19 -307.1652 d19
20 305.1027 3.5176 1.80610 33.27
21 -139.8486 0.5148
22 84.3581 3.8214 1.59349 67.00
23 -182.5452 1.0000 1.84666 23.78
24 811.1016 7.9000
25 (Aperture) ∞ 7.9164
26 48.7235 3.8942 1.58913 61.25
27 183.5032 0.1500
28 67.2019 0.9000 1.95375 32.32
29 39.2014 2.0725
30 53.4025 6.1050 1.43700 95.10
31 -53.4025 1.0000 1.91082 35.25
32 -308.2583 d32
33 251.9085 0.9000 1.87071 40.73
34 71.7942 10.0309
35 303.8818 4.2555 1.56883 56.04
36 -89.4946 0.1500
37 59.1502 4.3580 1.62041 60.34
38 -376.9348 d38
39 -216.5223 2.9225 1.67300 38.15
40 -72.3284 0.7528
41 -151.7296 1.0000 1.43700 95.10
42 44.3172 19.9501
43 -35.2519 0.9000 1.95375 32.32
44 118.4711 4.3638 1.85478 24.80
45 -51.0206 BF
Image plane ∞

[Various data]
Zoom ratio 9.31
Wide-angle medium telephoto focal length 62.03 183.64 577.73
F number 4.48 5.55 6.50
Full angle of view 2ω 39.35 13.32 4.23
Image height Y 21.63 21.63 21.63
Lens total length 307.89 364.39 407.88

[Variable interval data]
Wide angle
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 4.4174 4.4174 4.4174
d10 34.7575 34.7575 34.7575
d19 51.3574 51.3574 51.3574
d32 10.3019 10.3019 10.3019
d38 2.1949 2.2771 2.6364
BF 53.5844 53.5021 53.1429

Intermediate
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 81.0011 81.0011 81.0011
d10 14.6816 14.6816 14.6816
d19 26.1367 26.1367 26.1367
d32 6.2172 6.2172 6.2172
d38 7.8423 8.3089 10.2351
BF 77.2424 76.7756 74.8497

Telephoto
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 134.6875 134.6875 134.6875
d10 4.4816 4.4816 4.4816
d19 2.013 2.013 2.013
d32 12.3614 12.3614 12.3614
d38 4.389 7.7134 20.2935
BF 98.6753 95.3509 82.7706

[Lens group data]
Focal length
G1 1 237.55
G2 6 -60.92
G3 11 -246.41
G4 20 66.30
G5 33 72.87
G6 39 -57.90
G3a 11 76.82
G3b 15 -47.40

FIG. 23 is a lens configuration diagram of the imaging optical system according to the second embodiment of the present invention.

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 negative refractive power, and the fourth lens having a positive refractive power. The group G4, the fifth lens group G5 having a positive refractive power, and the sixth lens group G6 having a negative refractive power are arranged and configured.

The first lens group G1 is composed of a junction lens consisting of a negative meniscus lens L1 having a convex surface facing the object side, a positive meniscus lens L2 having a convex surface facing the object side, and a positive meniscus lens lens L3 having a convex surface facing the object side. It moves from the image side to the object side when scaling from the wide-angle end to the telephoto end.

The second lens group G2 is composed of a junction lens composed of a biconvex lens L4 and a biconcave lens L5, and a biconcave lens L6, and moves from the object side to the image side when scaling from the wide-angle end to the telephoto end.

The third lens group G3 is composed of a third lens group front group G3a having a positive refractive power and a third lens group rear group G3b having a negative refractive power, and is fixed to the image plane at the time of scaling.

The front group G3a of the third lens group is composed of a positive meniscus lens L7 having a convex surface facing the image side and a regular meniscus lens L8 having a convex surface facing the object side in order from the object side.

The rear group G3b of the third lens group is composed of a biconcave lens L9, a biconcave lens L10, and a junction lens of the biconvex lens L11 in order from the object side, and is driven in a direction orthogonal to the optical axis for vibration isolation.

The fourth lens group G4 includes a biconvex lens G12, a junction lens of a biconvex lens G13 and a biconcave lens G14, a positive meniscus lens L15 having a convex surface facing the object side, and a negative meniscus lens L16 having a convex surface facing the object side. It is composed of a junction lens of a biconvex lens L17 and a negative meniscus lens L18 with a convex surface facing the image side, and moves from the image side to the object side when scaling from the wide-angle end to the telephoto end.

Further, an aperture diaphragm S is provided in the air gap between the biconcave lens G14 in the fourth lens group and the positive meniscus lens L15.

The fifth lens group G5 is composed of a negative meniscus lens L19 having a convex surface facing the object side, a biconvex lens L20, and a positive meniscus lens L21 having a convex surface facing the object side. Move from the image side to the object side.

The sixth lens group G6 is a junction of a positive meniscus lens L22 having a convex surface facing the image side, a biconcave lens L23, a negative meniscus lens L24 having a convex surface facing the image side, and a positive meniscus lens L25 having a convex surface facing the image side. It is composed of a lens and moves from the image side to the telephoto side when scaling from the wide-angle end to the telephoto end, and moves from the object side to the image side when focusing from infinity to a short distance.

Subsequently, the specification values of the variable magnification imaging optical system according to the second embodiment are shown below.
Numerical Example 2
Unit: mm
[Surface data]
Face number rd nd vd
1 183.9776 3.0000 1.87071 40.73
2 111.6695 9.2434 1.49700 81.61
3 1038.7357 0.1500
4 124.1632 8.8849 1.43700 95.10
5 11713.5228 (d5)
6 260.4098 5.4297 1.80518 25.46
7 -136.5425 1.5000 1.87071 40.73
8 51.5497 5.7567
9 -1915.0039 1.5000 1.87071 40.73
10 356.5338 (d10)
11 -289.1074 3.5298 1.58267 46.42
12 -79.3512 0.1500
13 43.9807 3.2535 1.55032 75.50
14 108.8223 4.8012
15 -255.4092 0.9000 1.72916 54.67
16 65.2039 3.7710
17 -45.0305 1.0000 1.59522 67.73
18 100.1168 2.9967 1.85478 24.80
19 -204.2069 (d19)
20 249.0594 3.4298 1.80000 29.84
21 -151.6575 0.1500
22 108.2241 3.6712 1.62041 60.29
23 -105.6058 1.0000 1.84666 23.78
24-1920.6391 7.9000
25 (Aperture) ∞ 11.8488
26 52.3784 3.6236 1.60738 56.82
27 208.1356 0.1500
28 69.6524 0.9000 1.95375 32.32
29 42.3726 1.7616
30 52.3700 5.6639 1.43700 95.10
31 -52.3700 1.0000 1.91082 35.25
32 -329.3310 (d32)
33 189.2374 0.9000 1.87071 40.73
34 68.1615 12.8928
35 211.1402 5.0154 1.55032 75.50
36 -79.2839 0.1500
37 54.2332 4.3821 1.61772 49.81
38 658.9183 (d38)
39 -203.4089 3.2142 1.66672 48.32
40 -66.1828 0.6308
41 -246.7154 1.0000 1.43700 95.10
42 36.3220 16.6535
43 -28.4439 0.9000 1.95375 32.32
44 -124.5438 3.6090 1.84666 23.78
45 -38.6568 (BF)
Image plane ∞

[Various data]
Zoom ratio 9.46
Wide-angle medium telephoto focal length 51.58 162.07 488.17
F number 4.46 5.55 6.51
Full angle of view 2ω 46.99 15.03 4.99
Image height Y 21.63 21.63 21.63
Lens total length 307.18 358.10 402.20

[Variable interval data]
Wide angle
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 5.4721 5.4721 5.4721
d10 40.6626 40.6626 40.6626
d19 53.4398 53.4398 53.4398
d32 5.6835 5.6835 5.6835
d38 2.6085 2.6697 2.9376
BF 53.0015 52.9402 52.6723

Intermediate
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 81.2387 81.2387 81.2387
d10 15.8150 15.8150 15.8150
d19 26.4382 26.4382 26.4382
d32 2.6850 2.6850 2.6850
d38 7.5629 7.9448 9.5227
BF 78.0474 77.6658 76.0876

Telephoto
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 131.8230 131.8230 131.8230
d10 9.3250 9.3250 9.3250
d19 2.0000 2.0000 2.0000
d32 9.2546 9.2546 9.2546
d38 5.4174 7.9614 17.4802
BF 98.0614 95.5177 85.9986

[Lens group data]
Focal length
G1 1 229.00
G2 6 -58.11
G3 11 -190.43
G4 20 66.71
G5 33 70.21
G6 39 -60.22
G3a 11 76.72
G3b 15 -48.65

FIG. 45 is a lens configuration diagram of the imaging optical system according to the third embodiment of the present invention.

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 negative refractive power, and the fourth lens having a positive refractive power. The group G4, the fifth lens group G5 having a positive refractive power, and the sixth lens group G6 having a negative refractive power are arranged and configured.

The first lens group G1 is composed of a junction lens consisting of a negative meniscus lens L1 having a convex surface facing the object side, a positive meniscus lens L2 having a convex surface facing the object side, and a positive meniscus lens lens L3 having a convex surface facing the object side. It moves from the image side to the object side when scaling from the wide-angle end to the telephoto end.

The second lens group G2 is composed of a junction lens consisting of a positive meniscus lens L4 having a convex surface facing the object side, a negative meniscus lens L5 having a convex surface facing the object side, and a negative meniscus lens L6 having a convex surface facing the object side. , Moves from the object side to the image side when scaling from the wide-angle end to the telephoto end.

The third lens group G3 is composed of a third lens group front group G3a having a positive refractive power and a third lens group rear group G3b having a negative refractive power in order from the object side, and is fixed to the image plane at the time of scaling. Has been done.

The front group G3a of the third lens group is composed of a biconvex lens L7 and a positive meniscus lens L8 with a convex surface facing the object side.

The rear group G3b of the third lens group is composed of a biconcave lens L9, a biconcave lens L10, and a junction lens of the biconvex lens L11, and is driven in a direction orthogonal to the optical axis during vibration isolation.

The fourth lens group G4 includes a biconvex lens G12, a junction lens of a biconvex lens G13 and a biconcave lens G14, a positive meniscus lens L15 having a convex surface facing the object side, and a negative meniscus lens L16 having a convex surface facing the object side. It is composed of a junction lens of a biconvex lens L17 and a negative meniscus lens L18 with a convex surface facing the image side, and moves from the image side to the object side when scaling from the wide-angle end to the telephoto end.

Further, an aperture diaphragm S is provided in the air gap between the biconcave lens G14 in the fourth lens group G4 and the positive meniscus lens L15.

The fifth lens group G5 is composed of a negative meniscus lens L19 having a convex surface facing the object side, a biconvex lens L20, and a biconvex lens L21, and moves from the image side to the object side when scaling from the wide-angle end to the telephoto end. ..

The sixth lens group G6 is composed of a positive meniscus lens L22 with a convex surface facing the image side, a biconcave lens L23, and a negative meniscus lens L24 with a convex surface facing the image side. It moves from the image side to the telephoto side, and moves from the object side to the image side when focusing from infinity to a short distance.

Subsequently, the specification values of the variable magnification imaging optical system according to the third embodiment are shown below.
Numerical Example 3
Unit: mm
[Surface data]
Face number rd nd vd
1 180.3873 3.0000 1.87071 40.73
2 107.4126 9.1595 1.49700 81.61
3 1500.0000 0.1500
4 112.9244 8.5645 1.43700 95.10
5 1719.2821 (d5)
6 173.2640 3.3027 1.80809 22.76
7 904.2710 1.5000 1.87071 40.73
8 50.9405 5.1528
9 247.9259 1.5000 1.87071 40.73
10 97.8521 (d10)
11 601.2607 4.0012 1.62004 36.30
12 -120.8642 6.5594
13 41.5067 3.6039 1.51742 52.15
14 115.5161 4.7897
15 -692.5670 0.9000 1.72916 54.67
16 56.4878 4.0080
17 -43.1576 1.0000 1.59522 67.73
18 82.8474 3.0520 1.85478 24.80
19 -277.0573 (d19)
20 395.7015 2.9293 1.80420 46.50
21 -210.1387 0.1535
22 60.7452 4.2868 1.61997 63.88
23 -129.1969 1.0000 1.85025 30.05
24 385.3962 3.9000
25 (Aperture) ∞ 19.6439
26 60.9906 3.9364 1.60311 60.69
27 348.1042 0.1500
28 55.0197 0.9000 1.95375 32.32
29 36.3686 2.0483
30 49.6729 5.7977 1.43700 95.10
31 -49.6729 1.0000 1.91082 35.25
32 -197.6641 (d32)
33 487.0709 0.9000 1.88300 40.80
34 82.0305 1.0231
35 246.6120 3.9357 1.55032 75.50
36 -120.5742 0.1502
37 60.2847 10.4257 1.62004 36.30
38 -284.1651 (d38)
39 -184.5937 3.1443 1.67270 32.17
40 -60.4393 1.2634
41 -82.7876 1.0000 1.43700 95.10
42 38.9711 11.9188
43 -31.3723 0.9000 1.65844 50.85
44 -41.3921 (BF)
Image plane ∞

[Various data]
Zoom ratio 9.59
Wide-angle medium telephoto focal length 51.50 159.72 493.91
F number 4.41 5.57 6.55
Full angle of view 2ω 46.31 15.22 4.94
Image height Y 21.63 21.63 21.63
Lens total length 295.25 343.87 384.36

[Variable interval data]
Wide angle
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 4.0000 4.0000 4.0000
d10 34.0008 34.0008 34.0008
d19 52.6627 52.6627 52.6627
d32 7.2938 7.2938 7.2938
d38 2.1409 2.2214 2.5729
BF 54.5048 54.4242 54.0728

Intermediate
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 74.0285 74.0285 74.0285
d10 12.5874 12.5874 12.5874
d19 26.6098 26.6098 26.6098
d32 3.5463 3.5463 3.5463
d38 7.8799 8.3759 10.4435
BF 78.5663 78.0704 76.0025

Telephoto
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 122.2674 122.2674 122.2674
d10 4.8365 4.8365 4.8365
d19 2.0000 2.0000 2.0000
d32 11.1149 11.1149 11.1149
d38 4.2034 7.6861 21.638
BF 99.2839 95.801 81.8491

[Lens group data]
Focal length
G1 1 216.79
G2 6 -55.97
G3 11 -251.12
G4 20 66.14
G5 33 93.87
G6 39 -70.49
G3a 11 71.51
G3b 15 -46.02

FIG. 67 is a lens configuration diagram of the imaging optical system according to the fourth embodiment of the present invention.

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 negative refractive power, and the fourth lens having a positive refractive power. The group G4, the fifth lens group G5 having a positive refractive power, and the sixth lens group G6 having a negative refractive power are arranged and configured.

The first lens group G1 is composed of a junction lens consisting of a negative meniscus lens L1 having a convex surface facing the object side, a positive meniscus lens L2 having a convex surface facing the object side, and a positive meniscus lens lens L3 having a convex surface facing the object side. It moves from the image side to the object side when scaling from the wide-angle end to the telephoto end.

The second lens group G2 is composed of a junction lens consisting of a positive meniscus lens L4 having a convex surface facing the object side, a negative meniscus lens L5 having a convex surface facing the object side, and a negative meniscus lens L6 having a convex surface facing the object side. , Moves from the object side to the image side when scaling from the wide-angle end to the telephoto end.

The third lens group G3 is composed of a third lens group front group G3a having a positive refractive power and a third lens group rear group G3b having a negative refractive power, and is fixed to the image plane at the time of scaling.

The front group G3a of the third lens group is composed of a biconvex lens L7 and a positive meniscus lens L8 with a convex surface facing the object side.

The rear group G3b of the third lens group is composed of a biconcave lens L9, a biconcave lens L10, and a junction lens of the biconvex lens L11, and is driven in a direction orthogonal to the optical axis during vibration isolation.

The fourth lens group G4 includes a biconvex lens G12, a junction lens of a biconvex lens G13 and a biconcave lens G14, a positive meniscus lens L15 having a convex surface facing the object side, and a negative meniscus lens L16 having a convex surface facing the object side. It is composed of a junction lens of a biconvex lens L17 and a negative meniscus lens L18 with a convex surface facing the image side, and moves from the image side to the object side when scaling from the wide-angle end to the telephoto end.

Further, an aperture diaphragm S is provided in the air gap between the biconcave lens G14 in the fourth lens group G4 and the positive meniscus lens L15.

The fifth lens group G5 is composed of a negative meniscus lens L19 having a convex surface facing the object side, a biconvex lens L20, and a biconvex lens L21, and moves from the image side to the object side when scaling from the wide-angle end to the telephoto end. ..

The sixth lens group G6 is composed of a biconvex lens L22, a biconcave lens L23, a negative meniscus lens L24 with a convex surface facing the image side, and a positive meniscus lens L25 with a convex surface facing the image side. It moves from the image side to the telephoto side when scaling to the telephoto end, and moves from the object side to the image side when focusing from infinity to a short distance.

Subsequently, the specification values of the variable magnification imaging optical system according to the fourth embodiment are shown below.
Numerical Example 4
Unit: mm
[Surface data]
Face number rd nd vd
1 171.9924 3.0000 1.87071 40.73
2 106.9087 10.5044 1.49700 81.61
3 737.3729 0.1500
4 120.5906 10.0362 1.43700 95.10
5 3220.6046 (d5)
6 140.6883 2.9241 1.80518 25.46
7 375.3061 1.5000 1.87071 40.73
8 56.3665 3.7501
9 212.5784 1.5000 1.87071 40.73
10 78.0206 (d10)
11 82.2798 4.4358 1.64769 33.84
12 -763.8860 6.3116
13 46.7524 3.3924 1.51742 52.15
14 92.4670 5.4909
15 -3552.1258 0.9000 1.74320 49.34
16 57.4220 4.3820
17 -45.6440 1.0000 1.61997 63.88
18 84.2074 3.1611 1.84666 23.78
19 -345.4298 (d19)
20 379.2215 5.6272 1.80420 46.50
21 -111.5690 0.1500
22 80.1576 3.8547 1.51742 52.15
23 -164.2052 1.0000 1.92119 23.96
24 493.2938 7.9000
25 (Aperture) ∞ 5.0000
26 36.7697 4.5935 1.49700 81.61
27 117.0459 3.7180
28 40.9541 0.9000 1.95375 32.32
29 29.6940 2.8838
30 53.8220 5.4378 1.43700 95.10
31 -53.8220 1.0000 1.91082 35.25
32 -366.1637 (d32)
33 249.9802 0.9000 1.87071 40.73
34 79.1212 7.3074
35 185.5004 3.1609 1.54814 45.82
36 -91.3091 0.1500
37 55.9557 4.0714 1.54814 45.82
38 -1561.2362 (d38)
39 1304.8163 3.2247 1.62004 36.30
40 -72.7317 1.2945
41 -91.9317 1.0000 1.49700 81.61
42 35.4876 15.1550
43 -33.8892 0.9000 1.95375 32.32
44 -82.7667 2.8209 1.85478 24.80
45 -42.4486 (BF)
Image plane ∞

[Various data]
Zoom ratio 9.32
Wide-angle medium telephoto focal length 62.05 177.71 578.40
F number 4.43 5.50 6.50
Full angle of view 2ω 38.92 13.71 4.21
Image height Y 21.63 21.63 21.63
Lens total length 297.68 349.57 393.58

[Variable interval data]
Wide angle
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 4.0000 4.0000 4.0000
d10 33.2448 33.2448 33.2448
d19 51.3427 51.3427 51.3427
d32 6.6721 6.6721 6.6721
d38 3.3073 3.3949 3.7767
BF 54.6218 54.5341 54.1524

Intermediate
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 76.3056 76.3056 76.3056
d10 12.8328 12.8328 12.8328
d19 28.2208 28.2208 28.2208
d32 2.0000 2.0000 2.0000
d38 7.7754 8.248 10.2056
BF 77.9479 77.4752 75.5178

Telephoto
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 129.1227 129.1227 129.1227
d10 4.0283 4.0283 4.0283
d19 2.0000 2.0000 2.0000
d32 12.4798 12.4798 12.4798
d38 1.9972 5.6345 19.8088
BF 99.4669 95.8297 81.6552

[Lens group data]
Focal length
G1 1 229.42
G2 6 -60.27
G3 11 -327.21
G4 20 64.60
G5 33 78.45
G6 39 -61.61
G3a 11 71.46
G3b 15 -45.68

FIG. 89 is a lens configuration diagram of the imaging optical system according to the fifth embodiment of the present invention.

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 negative refractive power, and the fourth lens having a positive refractive power. The group G4, the fifth lens group G5 having a positive refractive power, and the sixth lens group G6 having a negative refractive power are arranged and configured.

The first lens group G1 is composed of a junction lens consisting of a negative meniscus lens L1 having a convex surface facing the object side, a positive meniscus lens L2 having a convex surface facing the object side, and a positive meniscus lens lens L3 having a convex surface facing the object side. It moves from the image side to the object side when scaling from the wide-angle end to the telephoto end.

The second lens group G2 is composed of a junction lens consisting of a biconvex lens L4 and a biconcave lens L5, and a negative meniscus lens L6 with a convex surface facing the object side. Move to.

The third lens group G3 is composed of a third lens group front group G3a having a positive refractive power and a third lens group rear group G3b having a negative refractive power in order from the object side, and is fixed to the image plane at the time of scaling. Has been done.

The front group G3a of the third lens group is composed of a biconvex lens L7 and a positive meniscus lens L8 with a convex surface facing the object side.

The rear group G3b of the third lens group is composed of a biconcave lens L9, a biconcave lens L10, and a junction lens of the biconvex lens L11, and is driven in a direction orthogonal to the optical axis during vibration isolation.

The fourth lens group G4 includes a biconvex lens G12, a junction lens of a biconvex lens G13 and a biconcave lens G14, a positive meniscus lens L15 having a convex surface facing the object side, and a negative meniscus lens L16 having a convex surface facing the object side. It is composed of a junction lens of a biconvex lens L17 and a negative meniscus lens L18 with a convex surface facing the image side, and moves from the image side to the object side when scaling from the wide-angle end to the telephoto end.

Further, an aperture diaphragm S is provided in the air gap between the biconcave lens G14 in the fourth lens group G4 and the positive meniscus lens L15.

The fifth lens group G5 is composed of a negative meniscus lens L19 having a convex surface facing the object side, a biconvex lens L20, and a positive meniscus lens L21 having a convex surface facing the object side. Move from the image side to the object side.

The sixth lens group G6 is composed of a biconvex lens L22, a biconcave lens L23, a biconcave lens L24 and a biconvex lens L25, and moves from the image side to the telephoto side when scaling from the wide-angle end to the telephoto end. It moves from the object side to the image side when focusing from infinity to a short distance.

Subsequently, the specification values of the variable magnification imaging optical system according to the fifth embodiment are shown below.
Numerical Example 5
Unit: mm
[Surface data]
Face number rd nd vd
1 193.9183 3.0000 1.87071 40.73
2 112.7009 10.6601 1.49700 81.61
3 1954.6224 0.1500
4 115.4053 10.2252 1.43700 95.10
5 1909.8680 (d5)
6 125.0396 4.0633 1.80518 25.46
7 -8685.5213 1.5000 1.87071 40.73
8 56.9223 3.6694
9 215.6973 1.5000 1.87071 40.73
10 71.6254 (d10)
11 106.7759 4.3569 1.62004 36.30
12 -253.2720 6.1339
13 41.5419 3.4109 1.51680 64.20
14 74.4874 5.5127
15 -3606.5946 0.9000 1.74320 49.34
16 57.7292 4.4098
17 -44.4736 1.0000 1.61997 63.88
18 89.2171 3.2201 1.85478 24.80
19 -242.2676 (d19)
20 254.2966 3.3635 1.80610 33.27
21 -163.4129 0.1500
22 58.5932 3.8645 1.59349 67.00
23 -616.5772 1.0000 1.85478 24.80
24 135.9209 7.9000
25 (Aperture) ∞ 5.0080
26 55.2100 4.1271 1.51680 64.20
27 985.6996 0.2023
28 45.5011 0.9000 1.95375 32.32
29 33.2247 2.5855
30 55.0730 5.5390 1.43700 95.10
31 -55.0730 1.0000 1.91082 35.25
32 -611.6706 (d32)
33 108.6949 0.9000 1.87071 40.73
34 72.1846 12.4091
35 117.8829 4.0484 1.54072 47.20
36 -105.3095 0.1500
37 62.1923 3.6393 1.55032 75.50
38 314.3486 (d38)
39 460.4669 2.9171 1.67300 38.15
40 -117.9258 1.1550
41 -222.3699 1.0000 1.43700 95.10
42 29.3273 10.8668
43 -45.5274 0.9000 1.95375 32.32
44 323.5961 3.2003 1.85478 24.80
45 -64.0272 (BF)
Image plane ∞

[Various data]
Zoom ratio 9.32
Wide-angle medium telephoto focal length 62.07 180.98 578.34
F number 4.45 5.52 6.50
Full angle of view 2ω 38.65 13.42 4.21
Image height Y 21.63 21.63 21.63
Lens total length 297.37 348.55 390.08

[Variable interval data]
Wide angle
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 4.0000 4.0000 4.0000
d10 33.8685 33.8685 33.8685
d19 50.8036 50.8036 50.8036
d32 6.5986 6.5986 6.5986
d38 5.0364 5.1218 5.4935
BF 56.5239 56.4384 56.0670

Intermediate
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 75.7681 75.7681 75.7681
d10 13.2773 13.2773 13.2773
d19 28.0374 28.0374 28.0374
d32 2.1055 2.1055 2.1055
d38 8.5152 8.9821 10.9095
BF 80.3043 79.8376 77.9100

Telephoto
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 126.036 126.036 126.036
d10 4.5449 4.5449 4.5449
d19 2.0000 2.0000 2.0000
d32 13.4942 13.4942 13.4942
d38 2.0874 5.5385 18.7932
BF 101.3808 97.9294 84.6750

[Lens group data]
Focal length
G1 1 224.38
G2 6 -59.44
G3 11 -333.47
G4 20 68.21
G5 33 73.44
G6 39 -58.36
G3a 11 73.18
G3b 15 -47.50

FIG. 111 is a lens configuration diagram of the imaging optical system according to the sixth embodiment of the present invention.

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 negative refractive power, and the fourth lens having a positive refractive power. The group G4, the fifth lens group G5 having a positive refractive power, and the sixth lens group G6 having a negative refractive power are arranged and configured.

The first lens group G1 is composed of a junction lens consisting of a negative meniscus lens L1 having a convex surface facing the object side, a positive meniscus lens L2 having a convex surface facing the object side, and a positive meniscus lens lens L3 having a convex surface facing the object side. It moves from the image side to the object side when scaling from the wide-angle end to the telephoto end.

The second lens group G2 is composed of a junction lens consisting of a positive meniscus lens L4 having a convex surface facing the object side, a negative meniscus lens L5 having a convex surface facing the object side, and a negative meniscus lens L6 having a convex surface facing the object side. , Moves from the object side to the image side when scaling from the wide-angle end to the telephoto end.

The third lens group G3 is composed of a third lens group front group G3a having a positive refractive power and a third lens group rear group G3b having a negative refractive power in order from the object side, and is fixed to the image plane at the time of scaling. Has been done.

The front group G3a of the third lens group is composed of a biconvex lens L7 and a positive meniscus lens L8 with a convex surface facing the object side.

The rear group G3b of the third lens group is composed of a negative meniscus lens L9 having a convex surface facing the object side and a junction lens of a biconcave lens L10 and a biconvex lens L11, and is driven in a direction orthogonal to the optical axis for vibration isolation. Orthogonal.

The fourth lens group G4 includes a biconvex lens G12, a junction lens of a biconvex lens G13 and a biconcave lens G14, a positive meniscus lens L15 having a convex surface facing the object side, and a negative meniscus lens L16 having a convex surface facing the object side. It is composed of a junction lens of a biconvex lens L17 and a negative meniscus lens L18 with a convex surface facing the image side, and moves from the image side to the object side when scaling from the wide-angle end to the telephoto end.

Further, an aperture diaphragm S is provided in the air gap between the biconcave lens G14 in the fourth lens group G4 and the positive meniscus lens L15.

The fifth lens group G5 is composed of a negative meniscus lens L19 having a convex surface facing the object side, a biconvex lens L20, and a positive meniscus lens L21 having a convex surface facing the object side. It moves from the image side to the object side, and moves from the image side to the object side when focusing from infinity to a short distance.

The sixth lens group G6 is composed of a biconvex lens L22, a biconcave lens L23, a biconcave lens L24 and a biconvex lens L25, and moves from the image side to the telephoto side when scaling from the wide-angle end to the telephoto end. It moves from the object side to the image side when focusing from infinity to a short distance.

Subsequently, the specification values of the variable magnification imaging optical system according to the following Example 6 are shown.
Numerical Example 6
Unit: mm
[Surface data]
Face number rd nd vd
1 192.6245 3.0000 1.87071 40.73
2 112.5169 10.7760 1.49700 81.61
3 1984.0254 0.1500
4 115.7484 10.1202 1.43700 95.10
5 1724.6070 (d5)
6 114.9668 4.1760 1.80518 25.46
7 5851.5099 1.5000 1.87071 40.73
8 50.3830 4.1197
9 203.5260 1.5000 1.87071 40.73
10 78.9555 (d10)
11 112.6746 3.8686 1.62004 36.30
12 -260.7771 6.8226
13 39.8812 3.1526 1.51680 64.20
14 66.7555 5.4833
15 2298.3099 0.9000 1.74320 49.34
16 60.1530 4.3155
17 -45.0268 1.0000 1.61997 63.88
18 91.6412 3.1459 1.85478 24.80
19 -263.0854 (d19)
20 277.2869 3.3679 1.80610 33.27
21 -153.3145 0.1500
22 76.8555 3.8300 1.59349 67.00
23 -174.3225 1.0000 1.85478 24.80
24 275.1663 7.9000
25 (Aperture) ∞ 9.2084
26 47.6196 4.1709 1.51680 64.20
27 305.0231 0.4175
28 46.3664 0.9000 1.95375 32.32
29 33.3567 2.6103
30 55.8659 5.7561 1.43700 95.10
31 -55.8659 1.0000 1.91082 35.25
32 -562.2495 (d32)
33 101.2508 0.9000 1.87071 40.73
34 68.7716 9.9444
35 118.7990 3.1614 1.54072 47.20
36 -109.0007 0.1500
37 60.2608 3.8704 1.55032 75.50
38 768.7425 (d38)
39 592.9856 2.8644 1.67300 38.15
40 -118.7088 1.0148
41 -425.1087 1.0000 1.43700 95.10
42 27.4580 10.4317
43 -46.1064 0.9000 1.95375 32.32
44 85.7256 3.7392 1.85478 24.80
45 -66.7991 (BF)
Image plane ∞

[Various data]
Zoom ratio 9.33
Wide-angle medium telephoto focal length 62.02 177.99 578.40
F number 4.44 5.51 6.49
Full angle of view 2ω 38.40 13.60 4.20
Image height Y 21.63 21.63 21.63
Lens total length 298.22 348.79 391.31

[Variable interval data]
Wide angle
Infinity finite long distance finite short distance shooting distance inf 12.6694m 2.5985m
d5 4.0000 4.0000 4.0000
d10 34.0475 34.0475 34.0475
d19 50.0147 50.0147 50.0147
d32 6.1519 6.1430 6.1029
d38 5.0476 5.1243 5.4472
BF 56.6412 56.5732 56.2906


Intermediate
Infinity finite long distance finite short distance shooting distance inf 12.9380m 2.5997m
d5 74.8794 74.8794 74.8794
d10 13.7364 13.7364 13.7364
d19 27.5080 27.5080 27.5080
d32 2.0000 1.7031 1.1498
d38 8.0927 8.4706 10.0523
BF 80.2549 80.1733 79.1449

Telephoto
Infinity finite long distance finite short distance shooting distance inf 12.9996m 2.5899m
d5 126.7050 126.7050 126.7050
d10 4.4360 4.4360 4.4360
d19 2.0000 2.0000 2.0000
d32 12.3570 11.1260 6.4810
d38 1.9976 4.9694 15.6785
BF 101.5007 99.7596 93.6958

[Lens group data]
Focal length
G1 1 224.73
G2 6 -59.47
G3 11 -328.00
G4 20 69.41
G5 33 68.68
G6 39 -53.32
G3a 11 76.69
G3b 15 -49.57

FIG. 133 is a lens configuration diagram of the imaging optical system according to the seventh embodiment of the present invention.

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 negative refractive power, and the fourth lens having a positive refractive power. The group G4, the fifth lens group G5 having a positive refractive power, and the sixth lens group G6 having a negative refractive power are arranged and configured.

The first lens group G1 is a junction lens consisting of a negative meniscus lens L1 having a convex surface facing the object side, a positive meniscus lens L2 having a convex surface facing the object side, and a positive meniscus lens having a convex surface facing the object side in order from the object side. It is composed of a lens L3 and moves from the image side to the object side when scaling from the wide-angle end to the telephoto end.

The second lens group G2 consists of a junction lens consisting of a positive meniscus lens L4 having a convex surface facing the object side, a negative meniscus lens L5 having a convex surface facing the object side, and a negative meniscus lens having a convex surface facing the object side, in order from the object side. It is composed of L6 and moves from the object side to the image side when scaling from the wide-angle end to the telephoto end.

The third lens group G3 is composed of a third lens group front group G3a having a positive refractive power and a third lens group rear group G3b having a negative refractive power in order from the object side, and is fixed to the image plane at the time of scaling. Has been done.

The front group G3a of the third lens group is composed of a biconvex lens L7 and a positive meniscus lens L8 with a convex surface facing the object side.

The rear group G3b of the third lens group is composed of a biconcave lens L9, a biconcave lens L10, and a junction lens of the biconvex lens L11, and is driven in a direction orthogonal to the optical axis during vibration isolation.

The fourth lens group G4 includes a biconvex lens G12, a junction lens of a biconvex lens G13 and a biconcave lens G14, a positive meniscus lens L15 having a convex surface facing the object side, and a negative meniscus lens L16 having a convex surface facing the object side. It is composed of a junction lens of a biconvex lens L17 and a negative meniscus lens L18 with a convex surface facing the image side, and moves from the image side to the object side when scaling from the wide-angle end to the telephoto end.

Further, an aperture diaphragm S is provided in the air gap between the biconcave lens G14 in the fourth lens group G4 and the positive meniscus lens L15.

The fifth lens group G5 is composed of a junction lens of a biconvex lens L19, a negative meniscus lens L20 with a convex surface facing the image side, and a positive meniscus lens L21 with a convex surface facing the object side, and changes from a wide-angle end to a telephoto end. When doubling, it moves from the image side to the object side, and when focusing from infinity to a short distance, it moves from the image side to the object side.

The sixth lens group G6 is composed of a biconvex lens L22, a negative meniscus lens L23 with a convex surface facing the object side, and a junction lens of a biconcave lens L24 and a biconvex lens L25. It moves from the side to the telephoto side, and moves from the object side to the image side when focusing from infinity to a short distance.

Subsequently, the specification values of the variable magnification imaging optical system according to the seventh embodiment are shown below.
Numerical Example 7
Unit: mm
[Surface data]
Face number rd nd vd
1 192.5126 3.0000 1.87071 40.73
2 112.2679 10.9773 1.49700 81.61
3 1944.6507 0.1500
4 116.3211 10.2596 1.43700 95.10
5 1900.2215 (d5)
6 106.4166 4.2645 1.80518 25.46
7 1477.2058 1.5000 1.87071 40.73
8 49.5258 4.2268
9 205.5296 1.5000 1.87071 40.73
10 76.2964 (d10)
11 120.7193 3.9461 1.62004 36.30
12 -296.9205 6.5056
13 40.9267 3.3290 1.51680 64.20
14 78.5445 5.6508
15 -857.9657 0.9000 1.74320 49.34
16 62.2599 4.2242
17 -45.6861 1.0000 1.61997 63.88
18 90.9368 3.2036 1.85478 24.80
19 -239.9746 (d19)
20 301.9306 3.2784 1.80610 33.27
21 -165.8529 0.1500
22 64.9410 4.0150 1.59349 67.00
23 -221.1033 1.0000 1.85478 24.80
24 200.8814 7.9000
25 (Aperture) ∞ 8.4048
26 59.8463 3.9982 1.51680 64.20
27 3831.4603 0.1500
28 43.1359 0.9000 1.95375 32.32
29 32.8588 2.7257
30 57.1861 5.6556 1.43700 95.10
31 -57.1861 1.0000 1.91082 35.25
32 -707.9463 (d32)
33 219.9242 3.1584 1.54072 47.20
34 -70.3601 1.0000 1.87071 40.73
35 -101.9088 0.1500
36 63.1802 3.6731 1.55032 75.50
37 575.3405 (d37)
38 283.2877 2.8457 1.67300 38.15
39 -143.1587 0.7946
40 319.5211 1.0000 1.43700 95.10
41 25.6525 8.5298
42 -44.1468 0.9000 1.95375 32.32
43 62.1213 5.4762 1.85478 24.80
44 -70.5578 (BF)
Image plane ∞

[Various data]
Zoom ratio 9.32
Wide-angle medium telephoto focal length 62.05 179.34 578.36
F number 4.46 5.55 6.49
Full angle of view 2ω 38.35 13.49 4.20
Image height Y 21.63 21.63 21.63
Lens total length 296.49 347.08 389.64

[Variable interval data]
Wide angle
Point at infinity finite distance finite short distance
inf 12.8516m 2.5957m
d5 4.0000 4.0000 4.0000
d10 34.5447 34.5447 34.5447
d19 48.888 48.888 48.888
d32 15.8559 15.8345 15.7376
d37 4.9469 5.0218 5.3431
BF 56.9136 56.8602 56.6357

Intermediate
Point at infinity finite distance finite short distance
inf 13.0397m 2.6458m
d5 75.4218 75.4218 75.4218
d10 13.7107 13.7107 13.7107
d19 27.195 27.1950 27.1950
d32 10.8073 10.5623 9.8236
d37 8.0431 8.4281 9.9901
BF 80.5587 80.4189 79.5956

Telephoto
Point at infinity finite distance finite short distance
inf 12.8079m 2.5878m
d5 127.1326 127.1326 127.1326
d10 4.5590 4.5590 4.5590
d19 2.0000 2.0000 2.0000
d32 20.7217 19.4049 14.6041
d37 1.9977 5.0210 15.8831
BF 101.8846 100.1787 94.1169

[Lens group data]
Focal length
G1 1 225.03
G2 6 -59.20
G3 11 -308.95
G4 20 69.58
G5 33 71.15
G6 38 -53.38
G3a 11 75.97
G3b 15 -49.05

FIG. 155 is a lens configuration diagram of the imaging optical system according to the eighth embodiment of the present invention.

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 negative refractive power, and the fourth lens having a positive refractive power. The group G4, the fifth lens group G5 having a positive refractive power, and the sixth lens group G6 having a negative refractive power are arranged and configured.

The first lens group G1 is composed of a junction lens consisting of a negative meniscus lens L1 having a convex surface facing the object side, a positive meniscus lens L2 having a convex surface facing the object side, and a positive meniscus lens lens L3 having a convex surface facing the object side. It moves from the image side to the object side when scaling from the wide-angle end to the telephoto end.

The second lens group G2 is composed of a junction lens consisting of a negative meniscus lens L4 having a convex surface facing the object side, a positive meniscus lens L5 having a convex surface facing the object side, and a negative meniscus lens L6 having a convex surface facing the object side. , Moves from the object side to the image side when scaling from the wide-angle end to the telephoto end.

The third lens group G3 is composed of a third lens group front group G3a having a positive refractive power and a third lens group rear group G3b having a negative refractive power, and is fixed to the image plane at the time of scaling.

The front group G3a of the third lens group is composed of a biconvex lens L7 and a positive meniscus lens L8 with a convex surface facing the object side.

The rear G3b of the third lens group is composed of a negative meniscus lens L9 having a convex surface facing the object side and a junction lens of a biconcave lens L10 and a biconvex lens L11, and is driven in a direction orthogonal to the optical axis for vibration isolation. ..

The fourth lens group G4 includes a biconvex lens G12, a junction lens of a biconvex lens G13 and a biconcave lens G14, a positive meniscus lens L15 having a convex surface facing the object side, and a negative meniscus lens L16 having a convex surface facing the object side. It is composed of a junction lens of a biconvex lens L17 and a negative meniscus lens L18 with a convex surface facing the image side, and moves from the image side to the object side when scaling from the wide-angle end to the telephoto end.

Further, an aperture diaphragm S is provided in the air gap between the biconcave lens G14 in the fourth lens group G4 and the positive meniscus lens L15.

The fifth lens group G5 is composed of a negative meniscus lens L19 having a convex surface facing the object side, a biconvex lens L20, and a positive meniscus lens L21 having a convex surface facing the object side. Move from the image side to the object side.

The sixth lens group G6 is composed of a biconvex lens L22, a biconcave lens L23, a biconcave lens L24 and a biconvex lens L25, and moves from the image side to the telephoto side when scaling from the wide-angle end to the telephoto end. It moves from the object side to the image side when focusing from infinity to a short distance.

Subsequently, the specification values of the variable magnification imaging optical system according to the eighth embodiment are shown below.
Numerical Example 8
Unit: mm
[Surface data]
Face number rd nd vd
1 195.0864 3.0000 1.87071 40.73
2 112.2000 10.6715 1.49700 81.61
3 2015.5812 0.1500
4 114.6688 10.2048 1.43700 95.10
5 1943.0237 (d5)
6 161.1555 1.5000 1.87071 40.73
7 37.8572 5.2636 1.72825 28.32
8 65.1111 2.2582
9 123.5592 1.5000 1.87071 40.73
10 65.9196 (d10)
11 135.3943 4.1223 1.62004 36.30
12 -226.4852 6.3495
13 37.3781 3.0945 1.51680 64.20
14 57.4246 5.7064
15 2922.7562 0.9000 1.74320 49.34
16 56.4129 4.4965
17 -43.3948 1.0000 1.61997 63.88
18 88.0469 3.2707 1.85478 24.80
19 -229.4553 (d19)
20 247.7660 3.4934 1.80610 33.27
21 -142.7463 0.1500
22 58.2780 3.8616 1.59349 67.00
23 -923.9465 1.0000 1.85478 24.80
24 135.7377 7.9000
25 (Aperture) ∞ 5.0000
26 56.1488 3.9198 1.48749 70.44
27 620.1867 0.1500
28 47.7950 0.9000 1.95375 32.32
29 34.7120 2.4490
30 55.4002 5.5414 1.43700 95.10
31 -55.4002 1.0000 1.91082 35.25
32 -915.4361 (d32)
33 77.6585 0.9000 1.87071 40.73
34 57.4732 14.2263
35 95.4063 3.3859 1.51742 52.15
36 -108.6274 0.1500
37 72.4085 3.5102 1.55032 75.50
38 389.6026 (d38)
39 447.5412 2.9525 1.67300 38.15
40 -124.1445 1.1440
41 -252.3647 1.0000 1.43700 95.10
42 31.7093 14.0095
43 -45.7595 0.9000 1.95375 32.32
44 394.6031 3.2862 1.85478 24.80
45 -64.1992 (BF)
Image plane ∞

[Various data]
Zoom ratio 9.31
Wide-angle medium telephoto focal length 62.08 180.74 578.24
F number 4.49 5.55 6.50
Full angle of view 2ω 38.70 13.45 4.21
Image height Y 21.63 21.63 21.63
Lens total length 299.31 350.97 392.88

[Variable interval data]
Wide angle
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 4.0000 4.0000 4.0000
d10 34.1670 34.1670 34.1670
d19 50.3014 50.3014 50.3014
d32 7.2934 7.2934 7.2934
d38 4.3094 4.4030 4.8110
BF 54.9199 54.8262 54.4183

Intermediate
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 76.1088 76.1088 76.1088
d10 13.7174 13.7174 13.7174
d19 27.8928 27.8928 27.8928
d32 2.0000 2.0000 2.0000
d38 8.1887 8.7011 10.8208
BF 78.7425 78.2298 76.1106

Telephoto
Infinity finite long distance finite short distance shooting distance inf 13m 2.6m
d5 126.7677 126.7677 126.7677
d10 4.9670 4.9670 4.9670
d19 2.0000 2.0000 2.0000
d32 13.0218 13.0218 13.0218
d38 2.0385 5.8542 20.6340
BF 99.7637 95.9482 81.1682

[Lens group data]
Focal length
G1 1 224.65
G2 6 -63.76
G3 11 -207.93
G4 20 67.85
G5 33 75.05
G6 39 -62.36
G3a 11 81.93
G3b 15 -47.63

In the variable magnification imaging optical system provided with the vibration isolation function of the present invention, it is desirable to further include the following configuration.

It is desirable that all the air interfaces in the second lens group G2 are surfaces convex toward the object. This is because by reducing the angle between the main ray of the peripheral image angle passing through the second lens group G2 at the wide-angle end and the normal line of the air interface having a large relative refractive index, the axes of coma aberration and astigmatism are reduced. It is possible to reduce the occurrence of astigmatism and ensure imaging performance over the entire screen at the wide-angle end.

It is desirable to move the 6th lens group G6 as described above when focusing from infinity to a short distance, but the 5th lens group G5 may be moved together with the 6th lens group G6 as shown in the examples. .. Further, even if only the 5th lens group G5 or a part of the 5th lens group G5 to the 6th lens group G6 is moved so that the air spacing between the 5th lens group G5 and the 6th lens group G6 changes. good.

In each embodiment, the aperture diaphragm S is provided inside the fourth lens group G4, but it can also be arranged on the front side or the rear side of the fourth lens group G4. When the aperture stop S is placed on the front side of the fourth lens group G4, the aperture stop S and the vibration isolation drive mechanism are adjacent to each other because the third lens group rear group G3b is an anti-vibration group. difficult. When the aperture diaphragm S is placed behind the fourth lens group G4, the entrance pupil moves to the image side and the main ray passing position in the group before the diaphragm moves away from the optical axis. As the diameter of the second lens group G2 increases, the weight of the second lens group G2 tends to increase.

Therefore, it is most preferable to arrange the aperture stop S inside the fourth lens group G4. However, if the above problem can be solved, the essential effect of the present invention does not change even if the position of the aperture stop S is not inside the fourth lens group G4.

The above-mentioned above shows the values corresponding to the conditional expressions corresponding to each embodiment.
Conditional expression Example 1 Example 2 Example 3 Example 4
f1 / ft 0.41 0.47 0.44 0.40
| ft / f2 | 9.5 8.4 8.8 9.6 9.6
{(n2-n1) / r2} / {(n1-1) / r1} -0.72 -0.71 -0.72 -0.69
r3 / bf1 0.80 0.99 1.60 0.70
ht / r2 0.39 0.34 0.35 0.42
ft / fw 9.31 9.46 9.59 9.32
LT / ft 0.71 0.82 0.78 0.68
β6 2.9 2.8 2.5 2.8
f3 / f2 4.04 3.28 4.49 5.43
| f3a / f3b | 1.62 1.58 1.55 1.56
β3b -0.87 -0.79 -0.89 -1.07
| f2 / f3b | 1.29 1.19 1.22 1.32

Conditional expression Example 5 Example 6 Example 7 Example 8
f1 / ft 0.39 0.39 0.39 0.39
| ft / f2 | 9.7 9.7 9.8 9.1
{(n2-n1) / r2} / {(n1-1) / r1} -0.74 -0.73 -0.74 -0.75
r3 / bf1 1.88 1.97 1.91 1.87
ht / r2 0.39 0.40 0.40 0.40
ft / fw 9.32 9.33 9.32 9.31
LT / ft 0.67 0.68 0.67 0.68
β6 2.9 3.1 3.1 2.8
f3 / f2 5.61 5.52 5.22 3.26
| f3a / f3b | 1.54 1.55 1.55 1.72
β3b -1.09 -1.03 -1.04 -0.99
| f2 / f3b | 1.25 1.20 1.21 1.34

G1 1st lens group G2 2nd lens group G3 3rd lens group G3a 3rd lens group Front group G3b 3rd lens group Rear group G4 4th lens group G5 5th lens group G6 6th lens group S Aperture aperture I image plane

Claims (9)

From the object side,
The first lens group G1 having a positive refractive power,
The second lens group G2, which has a negative refractive power,
The third lens group G3, which has a negative refractive power,
The fourth lens group G4 having a positive refractive power,
The fifth lens group G5 having a positive refractive power,
It is composed of a sixth lens group G6 having a negative refractive power.
The aperture diaphragm S is arranged inside or near the fourth lens group G4, and is arranged.
When scaling from the wide-angle end to the telephoto end, the air spacing between each lens group changes,
The first lens group G1 moves to the object side, the second lens group G2 moves to the image side, and the third lens group G3 does not move to the image plane during scaling and focusing.
The third lens group G3 is composed of a third lens group front group G3a having a positive refractive power and a third lens group rear group G3b having a negative refractive power in order from the object side.
Vibration isolation is performed by displacing the G3b group in a direction orthogonal to the optical axis.
The first lens group G1 is composed of a junction lens composed of a negative lens L1 and a positive lens L2, and a positive lens L3.
Variable magnification imaging optical system characterized by satisfying the following conditional expression (1) 0.30 <f1 / ft <0.55
(2) 8.2 << | ft / f2 | <10.7
(3) -0.85 <{(n2-n1) / r2} / {(n1-1) / r1} <-0.50
(4) 0.50 <r3 / bf1 <2.00
fi: Synthetic focal distance of the i-th lens group ft: Synthetic focal distance of the entire optical system in the telephoto end and infinite focus state ri: Radius of curvature of the i-th optical surface of the optical system from the object side ni: Optical The d-line (wavelength 587.56 nm) refractive index bf1: of the medium between the i-th and i + 1-th optical planes from the object side of the system, which is the most image-side of the junction lens composed of the negative lens L1 and the positive lens L2. Distance from the surface apex to the image side focal point of the junction lens
The variable magnification imaging optical system according to claim 1, which satisfies the following conditional expression (5) 0.30 <ht / r2 <0.45.
ht: Radius of the entrance pupil at the telephoto end and in the in-focus state at infinity ri: Radius of curvature of the i-th optical surface from the object side of the optical system
The variable magnification imaging optical system according to claim 1 or 2, which satisfies the following conditional expression (6) 8.50 <ft / fw.
(7) 0.55 <LT / ft <0.85
ft: Synthetic focal length of the entire optical system in the telephoto end and infinity focus state fw: Synthetic focal length of the entire optical system in the wide-angle end and infinity focus state LT: Optical in the telephoto end and infinity focus state The length from the optical plane on the most object side of the system to the image
The variable magnification imaging optical system according to any one of claims 1 to 3, wherein the second lens group G2 has at least one positive lens and one negative lens.
The scaling according to any one of claims 1 to 4, wherein the group spacing between the fifth lens group G5 and the sixth lens group G6 changes when focusing from infinity to a short distance. Imaging optical system
The variable magnification imaging optical system according to claim 5, which satisfies the following conditional expression (8) 2.0 <β6 <4.0.
β6: Imaging magnification of the sixth lens group G6 at the telephoto end and in infinity in focus.
The variable magnification imaging optical system according to claim 5 or 6, wherein the sixth lens group G6 moves when focusing from an infinite distance to a short distance.
The variable magnification imaging optical system according to any one of claims 1 to 7, which satisfies the following conditional expression (9) 2.5 <f3 / f2 <6.0.
(10) 1.00 << | f3a / f3b | <2.50
fi: Composite focal length of the i-th lens group f3a: Composite focal length of the third lens group front group G3a f3b: Composite focal length of the third lens group rear group G3b group
The variable magnification imaging optical system (11) -1.50 <β3b <-0.50 according to any one of claims 1 to 8, which satisfies the following conditional expression.
(12) 0.85 <f2 / f3b <2.00
β3b: Imaging magnification fi of the third lens group rear group G3b at the telephoto end and infinite focus state: synthetic focal length f3b of the i-th lens group: synthetic focal length of the third lens group rear group G3b group

Images