JP5326434B2 - Variable magnification optical system and optical apparatus equipped with the variable magnification optical system - Google Patents

Description

The present invention, the variable magnification optical system, and to an optical apparatus including the variable magnification optical system.

Conventionally, a variable magnification optical system having an anti-vibration function has been proposed. (For example, refer to Patent Document 1).
JP 2006-106191 A

  However, better optical performance is required than conventional variable power optical systems.

The present invention has been made in view of such a problem, a variable magnification optical system can achieve a good optical performance, and an object thereof is to provide an optical apparatus including the variable magnification optical system To do.

In order to solve the above problems, a variable magnification optical system according to the present invention includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a positive refraction. a third lens group having a force, consists of a fourth lens group having positive refractive power, when the lens position state from the wide-angle end state to the telephoto end state change, the first lens group and the second lens group The distance between the second lens group and the third lens group decreases, the distance between the third lens group and the fourth lens group changes, and the third lens group increases in order from the object side. A third lens group having a refractive power of 3a and a third lens group having a negative refractive power, and moving the third lens group in a direction perpendicular to the optical axis. In order from the object side, a biconcave lens and a positive meniscus lens with a convex surface facing the object side are joined. A cemented lens. The focal length of the entire system in the wide-angle end state is fw, the focal length of the entire system in the telephoto end state is ft, the focal length of the third lens group is f3, and the lens position state from the wide-angle end state to the telephoto end state The movement distance on the optical axis of the first lens group when the lens changes is Δd1, and the movement distance on the optical axis of the third lens group when the lens position changes from the wide-angle end state to the telephoto end state is Δd3. When the total length in the wide-angle end state is Lw, the following formula 0.15 <(Lw · fw) / (Δd1 · ft) <0.58
0.42 <(Lw · fw) / (Δd3 · ft) <0.90
2.20 <f3 / fw <4.50
It is configured to satisfy the following conditions.

Also, in such a variable magnification optical system, when the focal length of the first lens group is f1, the following expression 3.50 <f1 / fw <8.00
It is preferable to satisfy the following conditions.

  In such a variable magnification optical system, it is preferable that the third lens group and the fourth lens group move in the object direction when the lens position changes from the wide-angle end state to the telephoto end state.

  In such a variable magnification optical system, it is preferable that the first lens unit moves in the object direction when the lens position changes from the wide-angle end state to the telephoto end state.

Further, such a variable magnification optical system has the following formula 0.30 <f3 / ft <1.00.
It is preferable to satisfy the following conditions.

  In addition, in such a variable magnification optical system, the distance between the third lens group and the fourth lens group in the wide-angle end state is larger than the distance between the third lens group and the fourth lens group in the telephoto end state. Preferably, it is configured.

Also, in such a variable magnification optical system, when the focal length of the fourth lens group is f4 and the back focus in the wide-angle end state is Bfw, the following expression 0.80 <f3 / f4 <1.60
1.90 <Bfw / fw <3.00
It is preferable to satisfy the following conditions.

  In such a variable magnification optical system, it is preferable that the most object side lens surface of the 3b lens group is formed in an aspherical shape.

  An optical apparatus according to the present invention includes any of the above-described variable magnification optical systems.

Variable magnification optical system according to the present invention, and, when forming the optical apparatus including the variable magnification optical system as described above, it is possible to achieve good optical performance.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the present specification, the wide-angle end state and the telephoto end state refer to an infinitely focused state unless otherwise specified. As shown in FIG. 1, the variable magnification optical system ZL includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a positive refractive power. And a fourth lens group G4 having a positive refractive power. When the lens position changes from the wide-angle end state to the telephoto end state, the distance between the first lens group G1 and the second lens group G2 increases, and the second lens group G2 and the third lens group G3 The distance decreases, the distance between the third lens group G3 and the fourth lens group G4 changes, and a part of the third lens group G3 is configured to move in a direction orthogonal to the optical axis.

  In the zoom optical system ZL, the third lens group G3 includes, in order from the object side, a third a lens group G3a having a positive refractive power and a third b lens group G3b having a negative refractive power. By moving the 3b lens group G3b in a direction perpendicular to the optical axis, the image plane is corrected when camera shake occurs. The third lens group G3 is suitable for incorporating an anti-vibration mechanism because the lens diameter can be reduced as compared with other lens groups.

  The third lens group G3 includes a third lens group G3a having a positive refractive power and a third lens group G3b having a negative refractive power, and the third lens group G3b is used as a vibration-proof lens group. By using it, it is possible to reduce the size of the vibration isolation mechanism and reduce the mass of the vibration isolation lens group. In addition, with such a refractive power distribution, it is possible to reduce degradation in imaging performance when the anti-vibration 3b lens group G3b is moved in a direction orthogonal to the optical axis.

  The third lens group G3b is preferably composed of a cemented lens in which, in order from the object side, a biconcave lens and a positive meniscus lens having a convex surface directed toward the object side are cemented. Thereby, the chromatic aberration of the on-axis ray and the off-axis ray can be corrected satisfactorily, and the aberration can be corrected satisfactorily with respect to various aberrations that occur during image stabilization.

  In addition, it is desirable that the most object side lens surface of the third lens group G3b be formed in an aspherical shape. Thereby, even when the third b lens group G3b is decentered (that is, when it is moved during image stabilization), the deterioration of the decentration coma aberration can be sufficiently reduced.

  In the variable power optical system ZL, it is desirable that the third lens group G3 and the fourth lens group G4 move in the object direction when the lens position changes from the wide-angle end state to the telephoto end state. As a result, the moving mechanism for moving each lens group can have a simple configuration, and the variable magnification optical system ZL can be reduced in size, and the overall length of the lens barrel having the variable magnification optical system ZL is shortened. It becomes possible.

  In the variable magnification optical system ZL, it is desirable that the first lens group G1 moves in the object direction when the lens position changes from the wide-angle end state to the telephoto end state. As a result, the moving mechanism for moving each lens group can have a simple configuration and the entire length can be reduced.

  In the variable magnification optical system ZL, the distance between the third lens group G3 and the fourth lens group G4 in the wide-angle end state is larger than the distance between the third lens group G3 and the fourth lens group G4 in the telephoto end state. It is desirable to be configured as follows. Thereby, field curvature at the time of shifting from the wide-angle end state to the telephoto end state can be suppressed.

  In this variable magnification optical system ZL, the focal length of the entire system in the wide-angle end state is fw, the focal length of the entire system in the telephoto end state is ft, and the lens position state changes from the wide-angle end state to the telephoto end state. The moving distance on the optical axis of the first lens group G1 when the lens is moved is Δd1, and the moving distance on the optical axis of the third lens group G3 when the lens position is changed from the wide-angle end state to the telephoto end state is Δd3. When the total length in the wide-angle end state is Lw, it is desirable to satisfy the following conditional expressions (1), (2) and (3).

0.15 <(Lw · fw) / (Δd1 · ft) <0.58 (1)
0.42 <(Lw · fw) / (Δd3 · ft) <0.90 (2)
2.20 <f3 / fw <4.50 (3)

  Conditional expression (1) defines a full length range suitable for ensuring imaging performance with zoom magnification. If the upper limit of conditional expression (1) is exceeded, the total length at the wide-angle end becomes large, the diameter of the lens arranged closest to the object side becomes large, and the height of the off-axis rays increases. Correction of aberration and curvature of field becomes difficult, and distortion at the telephoto end increases to the plus side, which is not preferable. The upper limit value of conditional expression (1) is preferably 0.55, 0.50, and 0.48. On the other hand, if the lower limit of conditional expression (1) is not reached, the focal length of the first lens group G1 is reduced in order to reduce the movement distance Δd1 of the first lens group G1 on the optical axis, and off-axis aberration correction is performed. Astigmatism and curvature of field are difficult to correct, and distortion at the wide-angle end becomes negatively large, which is not preferable. The lower limit value of conditional expression (1) is preferably 0.20, 0.25, 0.30.

  Conditional expression (2) defines the moving distance of the third lens group G3 according to the zoom magnification. If the upper limit of conditional expression (2) is exceeded, the moving amount of the third lens group G3 decreases, the moving amount of the first lens group G1 increases, and the total length at the telephoto end increases. Alternatively, the amount of movement of the fourth lens group G4 increases and it becomes difficult to ensure the back focus. Further, it is not preferable because the decentration coma when the decentering occurs between the third lens group G3 and the fourth lens group G4 due to a manufacturing error increases and it becomes difficult to correct the deterioration of the imaging performance. The upper limit value of conditional expression (2) is preferably 0.81, 0.75, and 0.62. On the other hand, if the lower limit of conditional expression (2) is not reached, the focal length of the third lens group G3 increases and the amount of movement increases. This is not preferable because the correction movement amount of the third lens group G3b at the time of image stabilization is increased and the size of the image stabilization mechanism is increased. In order to mitigate this influence, it is not preferable to reduce the focal lengths of the first lens group G1 and the second lens group G2, because this causes deterioration of spherical aberration in the telephoto end state. In addition, it is preferable to set the lower limit of conditional expression (2) to 0.44 and 0.46.

  Conditional expression (3) defines the focal length range of the third lens group G3 suitable for securing the back focus and alleviating the performance deterioration due to manufacturing errors. If the upper limit value of conditional expression (3) is exceeded, the focal length of the third lens group G3 becomes long, the overall length and diameter at the wide angle end become large, and it becomes difficult to put to practical use. In addition, the diaphragm mechanism and the vibration isolation mechanism are undesirably increased in size. It is not preferable to shorten the focal length of the second lens group G2 in order to mitigate this influence because off-axis aberrations at the wide-angle end are deteriorated. In addition, it is preferable that the upper limit value of the conditional expression (3) is 3.80, 3.50, 3.22. On the other hand, if the lower limit value of conditional expression (3) is not reached, the back focus becomes longer, and an eccentric coma when an eccentricity occurs between the third lens group G3 and the fourth lens group G4 due to a manufacturing error. This is not preferable because it becomes large and it becomes difficult to correct the deterioration of the imaging performance. In addition, it is preferable that the lower limit value of conditional expression (3) is 2.27, 2.34, 2.40.

  Further, in the zoom optical system ZL, when the focal length of the entire system in the wide-angle end state is fw and the focal length of the first lens group G1 is f1, the following conditional expression (4) may be satisfied. desirable.

3.50 <f1 / fw <8.00 (4)

  Conditional expression (4) defines the focal length range of the first lens group G1 suitable for ensuring back focus and imaging performance. If the upper limit of conditional expression (4) is exceeded, the focal length of the first lens group G1 becomes longer, the overall length and diameter of the variable magnification optical system ZL become larger, and the height of off-axis rays becomes higher. Correction of curvature of field becomes difficult. Further, the distortion at the telephoto end is not preferable because it increases on the plus side. In addition, it is preferable to set the upper limit value of conditional expression (4) to 7.26, 6.52, 6.00. On the other hand, if the lower limit value of conditional expression (4) is not reached, the back focus becomes longer and the focal length of the first lens group G1 becomes shorter, so that off-axis aberrations (for example, astigmatism and field curvature) are reduced. Correction becomes difficult. Further, it is not preferable because the imaging performance at the telephoto end is deteriorated at the time of high zooming in which the distortion at the telephoto end increases to the plus side. In addition, it is preferable that the lower limit value of conditional expression (4) is 4.00 and 4.50.

  Further, in the variable magnification optical system ZL, when the focal length of the third lens group G3 is f3 and the focal length of the entire system in the telephoto end state is ft, the following conditional expression (5) may be satisfied. desirable.

0.30 <f3 / ft <1.00 (5)

  Conditional expression (5) defines the focal length of the third lens group with respect to the focal length of the variable magnification optical system ZL in the telephoto end state. If the upper limit value of conditional expression (5) is exceeded, the total length and diameter of the variable magnification optical system ZL will become large, making it difficult to put to practical use. In addition, the aperture stop mechanism and the vibration isolation mechanism are undesirably increased. It is not preferable to shorten the focal length of the second lens group G2 in order to alleviate this influence, because the astigmatism and the field curvature in the wide-angle end state are deteriorated. In addition, it is preferable that the upper limit value of conditional expression (5) is 0.82, 0.70, and 0.63. On the other hand, if the lower limit value of conditional expression (5) is not reached, the decentration coma aberration caused by the manufacturing error such as the relative decentration of the lens group becomes significant, which is not preferable. In addition, the spherical aberration is deteriorated in the telephoto end state. In addition, it is preferable that the lower limit value of conditional expression (5) is 0.31, 0.33, and 0.35.

  In the variable magnification optical system ZL, the focal length of the entire system in the wide-angle end state is fw, the focal length of the third lens group G3 is f3, and the focal length of the fourth lens group G4 is f4. When the back focus at is Bfw, it is desirable to satisfy the following conditional expressions (6) and (7).

0.80 <f3 / f4 <1.60 (6)
1.90 <Bfw / fw <3.00 (7)

  Conditional expression (6) defines the ratio of the focal lengths of the third lens group G3 and the fourth lens group G4, which are suitable for securing the back focus and alleviating performance deterioration due to manufacturing errors. By satisfying conditional expression (6), off-axis aberrations such as curvature of field and coma at the wide-angle end, and spherical aberration, coma and chromatic aberration at the telephoto end are excellent without reducing the back focus. Optical performance deterioration such as coma due to decentration due to manufacturing errors can be reduced. If the upper limit of conditional expression (6) is exceeded, the focal length of the fourth lens group G4 becomes relatively short, which makes it difficult to correct coma in the wide-angle end state and coma in the telephoto end state. In addition, optical performance deterioration due to decentration due to manufacturing errors becomes significant, which is not preferable. In addition, it is preferable to set the upper limit value of conditional expression (6) to 1.40 and 1.21. On the other hand, if the lower limit value of conditional expression (6) is not reached, the focal length of the third lens group G3 becomes relatively short, which is not preferable because the back focus is shortened. In order to avoid this, it is not preferable to shorten the focal length of the second lens group G2, because it causes deterioration of off-axis aberrations in the wide-angle end state. In addition, it is preferable to set the lower limit value of conditional expression (6) to 0.86 and 0.90.

  Conditional expression (7) defines a back focus range suitable for a lens interchangeable digital single-lens reflex camera. Exceeding the upper limit value of conditional expression (7) is not preferable because the back focus becomes too long and the overall length of the lens is increased. It is preferable that the upper limit value of conditional expression (7) is 2.69, 2.50, 2.37. On the other hand, if the lower limit value of conditional expression (7) is not reached, the back focus is shortened, causing interference between the lens rear portion and the mirror of the single-lens reflex camera. In addition, it is preferable that the lower limit value of the conditional expression (7) is 1.95, 2.00.

  FIG. 21 is a schematic cross-sectional view of a digital single-lens reflex camera 1 (hereinafter simply referred to as a camera) as an optical apparatus including the above-described variable magnification optical system ZL. In this camera 1, light from an object (subject) (not shown) is collected by the taking lens 2 (variable magnification optical system ZL) and imaged on the focusing screen 4 via the quick return mirror 3. The light imaged on the focusing screen 4 is reflected a plurality of times in the pentaprism 5 and guided to the eyepiece lens 6. Thus, the photographer can observe the object (subject) image as an erect image through the eyepiece 6.

  Further, when a release button (not shown) is pressed by the photographer, the quick return mirror 3 is retracted out of the optical path, and light of an object (subject) (not shown) condensed by the photographing lens 2 is captured on the image sensor 7. Form an image. Thereby, the light from the object (subject) is captured by the image sensor 7 and recorded as an object (subject) image in a memory (not shown). In this way, the photographer can shoot an object (subject) with the camera 1. The camera 1 shown in FIG. 21 may hold the variable magnification optical system ZL in a removable manner, or may be formed integrally with the variable magnification optical system ZL. The camera 1 may be a so-called single-lens reflex camera or a compact camera without a quick return mirror or the like.

  In the above description and the embodiments described below, the variable magnification optical system ZL having a four-group configuration is shown. However, the above-described configuration conditions and the like can be applied to other group configurations such as the fifth group and the sixth group. It is. Further, the 3a lens group G3a and the 3b lens group G3b of the third lens group G3 can be moved separately during zooming.

  Alternatively, a single lens group, a plurality of lens groups, or a partial lens group may be moved in the optical axis direction to be a focusing lens group that performs focusing from an object at infinity to a near object. In this case, the focusing lens group can be applied to autofocus, and is also suitable for driving a motor for autofocus (such as an ultrasonic motor). In particular, the second lens group G2 is preferably a focusing lens group.

  The lens surface may be an aspherical surface. At this time, any one of an aspheric surface by grinding, a glass mold aspheric surface in which glass is formed into an aspheric shape by a mold, and a composite aspheric surface in which resin is formed in an aspheric shape on the surface of the glass may be used. The lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

  The aperture stop S is preferably arranged on the most object side in the vicinity of the third lens group G3 or between the second lens group G2 and the third lens group G3, but without providing a member as an aperture stop. The role may be substituted by a lens frame.

  Furthermore, an antireflection film having a high transmittance in a wide wavelength range is applied to each lens surface, thereby reducing flare and ghost and achieving high optical performance with high contrast.

  The zoom optical system ZL of the present embodiment has a focal length in terms of 35 mm film size of about 25 to 29 mm at the wide-angle end state, about 150 to 170 mm at the telephoto end state, and a zoom ratio of about 5 to 6. It is.

  In the variable magnification optical system ZL of the present embodiment, it is preferable that the first lens group G1 has two positive lens components and one negative lens component. In the first lens group G1, it is preferable to dispose the lens components in order of negative positive / positive in order from the object side. Also, it is preferable to bond the first and second lens components together.

  In the variable magnification optical system ZL of the present embodiment, it is preferable that the second lens group G2 has one positive lens component and three negative lens components. In the second lens group G2, it is preferable to dispose lens components in order of negative, negative, positive and negative in order from the object side.

  In the variable magnification optical system ZL of the present embodiment, it is preferable that the third-a lens group G3a has two positive lens components and one negative lens component. In the third-a lens group G3a, it is preferable to dispose lens components in order of positive / negative from the object side. The order of the lens components may be negative / positive / positive / positive / negative.

  In the zoom optical system ZL according to the present embodiment, it is preferable that the third lens group G3b has one positive lens component and one negative lens component. In addition, the arrangement of the lens components in the third lens group G3b may be negative or positive or negative in order from the object side, but they are preferably bonded and held by one lens holding portion.

  In the variable magnification optical system ZL of the present embodiment, it is preferable that the fourth lens group G4 has a lens configuration that can be changed in accordance with aberration correction during image stabilization.

  In addition, in order to explain the present invention in an easy-to-understand manner, the configuration requirements of the embodiment have been described, but it goes without saying that the present invention is not limited to this.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing the configuration of the variable magnification optical system ZL according to the present embodiment. The refractive power distribution of the variable magnification optical system ZL and the focal point from the wide-angle end state (W) to the telephoto end state (T). The state of movement of each lens group in the change of the distance state is indicated by an arrow below FIG. As shown in FIG. 1, the variable magnification optical system ZL according to the present embodiment has a first lens group G1 having a positive refractive power and a negative refractive power in order from the object side along the optical axis. The lens unit includes a second lens group G2, a third lens group G3 having a positive refractive power, and a fourth lens group G4 having a positive refractive power. When the lens position changes from the wide-angle end state to the telephoto end state, the air gap between the first lens group G1 and the second lens group G2 increases, and the air between the second lens group G2 and the third lens group G3. The first lens group G1, the third lens group G3, and the fourth lens group G4 move in the object direction so that the distance decreases and the air distance between the third lens group G3 and the fourth lens group G4 decreases. The second lens group moves to the image plane side. The third lens group G3 includes, in order from the object side, a third lens group G3a having a positive refractive power and a third lens group G3b having a negative refractive power. The third lens group G3b is an optical axis. By moving in the orthogonal direction, camera shake correction (anti-vibration) is performed.

  The aperture stop S is located between the second lens group G2 and the third lens group G3, and moves together with the 3a lens group G3a upon zooming from the wide-angle end state to the telephoto end state. The flare cut stop FS is located between the third lens group G3 and the fourth lens group G4 and does not move during image stabilization, but moves together with the third lens group G3 during zooming. Focusing from a long distance to a short distance is performed by moving the second lens group G2 in the object direction.

In each embodiment, the height of the aspheric surface in the direction perpendicular to the optical axis is y, and the distance (sag amount) along the optical axis from the tangential plane of the apex of each aspheric surface to each aspheric surface at height y. Is S (y), r is the radius of curvature of the reference sphere (paraxial radius of curvature), κ is the conic constant, and An is the nth-order aspheric coefficient, and is expressed by the following equation (a). . In the following examples, “E−n” indicates “× 10 ⁻ⁿ ”.

S (y) = (y ² / r) / {1+ (1−κ × y ² / r ² ) ^1/2 }
+ A4 × y ⁴ + A6 × y ⁶ + A8 × y ⁸ + A10 × y ¹⁰ (a)

  In each embodiment, the secondary aspheric coefficient A2 is zero. In the table of each example, an aspherical surface is marked with * on the left side of the surface number.

[First embodiment]
FIG. 1 is a diagram showing a configuration of a variable magnification optical system ZL1 according to the first example. In the variable magnification optical system ZL1 of FIG. 1, the first lens group G1 includes, in order from the object side, a cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12, and an object It comprises a positive meniscus lens L13 having a convex surface on the side. The second lens group G2, in order from the object side, includes a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a negative surface having a concave surface directed toward the object side. The negative meniscus lens L21 including the meniscus lens L24 and positioned closest to the object side of the second lens group G2 is an aspherical lens in which an aspherical surface is formed by providing a resin layer on the glass lens surface on the object side. The third lens group G3a of the third lens group G3 includes, in order from the object side, a biconvex positive lens L31, and a biconvex positive lens L32 and a negative meniscus lens L33 having a concave surface facing the object side. Consists of lenses. The third lens group G3b of the third lens group G3 includes, in order from the object side, a cemented lens of a biconcave negative lens L34 and a positive meniscus lens L35 having a convex surface facing the object side. The biconcave negative lens L34 located closest to the object side of G3b is an aspheric lens in which an aspheric surface is formed by providing a resin layer on the glass lens surface on the object side. The fourth lens group G4 includes, in order from the object, a biconvex positive lens L41, a cemented lens of a biconvex positive lens L42 and a biconcave negative lens L43, and a biconvex positive lens L44. The biconvex positive lens L41 that is configured and is located closest to the object side in the fourth lens group G4 is an aspheric lens having an aspheric lens surface on the object side.

  It is to be noted that the focal length of the entire system is f, and the image stabilization correction coefficient (ratio of the amount of image movement on the imaging surface to the amount of movement of the moving lens group in shake correction) corrects rotational shake at an angle θ with a K lens. For this purpose, the moving lens group for blur correction may be moved in the direction orthogonal to the optical axis by (f · tan θ) / K (this description is the same in the following embodiments). At the wide-angle end of the first embodiment, the image stabilization correction coefficient is 0.999, and the focal length is 18.50 (mm). Therefore, the 3b lens for correcting the rotation blur of 0.60 ° is used. The movement amount of the group G3b is 0.194 (mm). Further, at the telephoto end of the first embodiment, the image stabilization correction coefficient is 1.789 and the focal length is 131.00 (mm). Therefore, the first correction for correcting the rotation blur of 0.27 ° is performed. The moving amount of the 3b lens group G3b is 0.345 (mm).

  Table 1 below lists values of specifications of the first embodiment. In Table 1, f represents the focal length, FNO represents the F number, 2ω represents the angle of view (unit is “°”), and Bf represents the back focus. Furthermore, the surface number is the order of the lens surfaces from the object side along the direction of travel of the light beam, the surface interval is the distance on the optical axis from each optical surface to the next optical surface, and the Abbe number and refractive index are each The value for the d-line (λ = 587.6 nm) is shown. Here, “mm” is generally used for the focal length f, the radius of curvature, the surface interval, and other length units listed in all the following specifications, but the optical system is proportionally enlarged or reduced. However, since the same optical performance can be obtained, it is not limited to this. The curvature radius ∞ indicates a plane, and the refractive index of air 1.000 is omitted. The description of these symbols and the description of the specification table are the same in the following embodiments.

(Table 1)
Wide angle end Intermediate focal length Telephoto end
f = 18.50 to 70.00 to 131.00
FNO = 3.39 to 4.66 to 5.55
2ω = 77.88 to 22.29 to 12.14
Image height = 14.20 to 14.20 to 14.20
Total length = 131.568 to 170.966 to 191.247

Surface number Curvature radius Surface spacing Abbe number Refractive index
1 132.7091 2.0000 23.78 1.846660
2 69.0393 7.6047 70.23 1.487490
3 -613.4510 0.1000
4 58.5782 6.0340 50.88 1.658441
5 211.3695 (d5)
* 6 277.8767 0.1500 38.09 1.553890
7 133.7106 1.2000 46.63 1.816000
8 14.4529 6.6840
9 -36.6145 1.0000 46.63 1.816000
10 55.0282 0.1000
11 35.0000 3.9063 23.78 1.846660
12 -37.5947 1.0681
13 -22.3441 1.0000 47.38 1.788000
14 -56.4883 (d14)
15 ∞ 0.5000 (Aperture stop S)
16 38.9611 2.7439 64.19 1.516798
17 -45.5432 0.1000
18 24.9617 3.4225 81.61 1.497000
19 -36.3323 1.0000 32.35 1.850 260
20 -313.2423 3.0000
* 21 -34.6816 0.1000 38.09 1.553890
22 -35.1754 1.0000 64.10 1.516800
23 36.6948 1.5591 27.51 1.755199
24 52.5702 1.5000
25 ∞ (d25) (Flare cut aperture)
* 26 55.8550 3.9010 64.03 1.516120
27 -27.9232 0.5000
28 500.0000 3.3875 60.67 1.563839
29 -26.2504 1.3000 37.16 1.834000
30 46.2587 0.8872
31 110.0000 3.2902 50.89 1.658441
32 -38.6328 (Bf)

[Lens focal length and moving distance]
f1 = 98.396
f2 = -14.860
f3 = 47.189
f4 = 43.127
Δd1 = 59.697
Δd3 = 36.679

  In the first embodiment, the sixth, twenty-first, and twenty-sixth lens surfaces are aspherical. Table 2 below shows aspheric data, that is, the values of the conic constant κ and the aspheric constants A4 to A10.

(Table 2)
κ A4 A6 A8 A10
6th surface 1.0000 1.67350E-05 -3.76300E-08 8.64890E-11 -4.98470E-14
Side 21 5.9254 2.86560E-05 5.91680E-09 4.57110E-10 0.00000E + 00
26th surface -26.7202 -1.22480E-05 -2.80120E-08 -1.97490E-11 0.00000E + 00

  In the first embodiment, the axial air distance d5 between the first lens group G1 and the second lens group G2, the axial air distance d14 between the second lens group G2 and the third lens group G3, and the third lens group G3. The on-axis air gap d25 and the back focus Bf between the first lens group G4 and the fourth lens group G4 change during zooming. Table 3 below shows variable intervals at the respective focal lengths in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

(Table 3)
Wide angle end Intermediate focal length Telephoto end
f 18.500 70.000 131.000
d5 2.070 38.567 49.422
d14 26.242 8.138 1.800
d25 6.250 2.232 1.450
Bf 37.967 62.990 79.536

  Table 4 below shows values corresponding to the conditional expressions in the first embodiment. In Table 4, Lw is the total length in the wide-angle end state, fw is the focal length of the entire system in the wide-angle end state, ft is the focal length of the entire system in the telephoto end state, and Δd1 is from the wide-angle end state to the telephoto end state. The movement distance on the optical axis of the first lens group G1 when the lens position state changes until Δd3 is on the optical axis of the third lens group G3 when the lens position state changes from the wide-angle end state to the telephoto end state. F1 is the focal length of the first lens group G1, f3 is the focal length of the third lens group G3, f4 is the focal length of the fourth lens group G4, and Bfw is the back focus in the wide-angle end state. , Respectively. The description of this symbol is the same in the following embodiments.

(Table 4)
(1) (Lw · fw) / (Δd1 · ft) = 0.311
(2) (Lw · fw) / (Δd3 · ft) = 0.505
(3) f3 / fw = 2.551
(4) f1 / fw = 5.319
(5) f3 / ft = 0.360
(6) f3 / f4 = 1.94
(7) Bfw / fw = 2.052

  FIG. 2A shows an aberration diagram in the infinite focus state in the wide-angle end state of the first embodiment, FIG. 3 shows an aberration diagram in the infinite focus state in the intermediate focal length state, and FIG. FIG. 4A shows an aberration diagram in the infinitely focused state. Further, FIG. 2B shows a coma aberration diagram when the blur correction is performed with respect to the rotation blur of 0.60 ° in the infinity photographing state at the wide-angle end state of the first embodiment, and the telephoto of the first embodiment is shown in FIG. FIG. 4B shows a coma aberration diagram when blur correction is performed with respect to 0.27 ° rotational blur in the infinity photographing state in the end state.

  In each aberration diagram, FNO is an F number, A is a half angle of view (unit “°”), d is a d-line (λ = 587.6 nm), and g is a g-line (λ = 435.6 nm). Show. The spherical aberration diagram shows the F-number value corresponding to the maximum aperture, the astigmatism diagram and the distortion diagram show the maximum value of the field angle, and the coma diagram shows the value of each field angle. In the astigmatism diagram, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane. Further, in the spherical aberration diagram, the solid line indicates the spherical aberration. The description of this aberration diagram is the same in the following examples. As is apparent from the respective aberration diagrams, in the first embodiment, it is understood that various aberrations are well corrected in each focal length state from the wide-angle end state to the telephoto end state, and excellent imaging performance is obtained.

[Second Embodiment]
FIG. 5 is a diagram showing a configuration of the variable magnification optical system ZL2 according to the second example. In the variable magnification optical system ZL2 in FIG. 5, the first lens group G1 includes, in order from the object side, a cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12, and an object It comprises a positive meniscus lens L13 having a convex surface on the side. The second lens group G2, in order from the object side, includes a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a negative surface having a concave surface directed toward the object side. The negative meniscus lens L21 including the meniscus lens L24 and positioned closest to the object side of the second lens group G2 is an aspherical lens in which an aspherical surface is formed by providing a resin layer on the glass lens surface on the object side. The third lens group G3a of the third lens group G3 includes, in order from the object side, a biconvex positive lens L31, and a cemented lens of a biconvex positive lens L32 and a biconcave negative lens L33. The The third lens group G3b of the third lens group G3 includes, in order from the object side, a cemented lens of a biconcave negative lens L34 and a positive meniscus lens L35 having a convex surface facing the object side. The third lens group G3b The biconcave negative lens L34 located closest to the object side is an aspherical lens in which an aspherical surface is formed by providing a resin layer on the glass lens surface on the object side. The fourth lens group G4 includes, in order from the object, a biconvex positive lens L41, a cemented lens of a biconvex positive lens L42 and a biconcave negative lens L43, and a biconvex positive lens L44. The biconvex positive lens L41 that is configured and is located closest to the object side in the fourth lens group G4 is an aspheric lens having an aspheric lens surface on the object side.

  At the wide-angle end of the second embodiment, the image stabilization correction coefficient is 0.928, and the focal length is 18.50 (mm). Therefore, the second correction for correcting the rotation blur of 0.60 ° is performed. The moving amount of the 3b lens group G3b is 0.209 (mm). Further, at the telephoto end of the second embodiment, the image stabilization correction coefficient is 1.687 and the focal length is 131.00 (mm). The moving amount of the 3b lens group G3b is 0.369 (mm).

  Table 5 below lists values of specifications of the second embodiment.

(Table 5)
Wide angle end Intermediate focal length Telephoto end
f = 18.50 to 70.00 to 131.00
FNO = 3.47 to 5.11 to 5.73
2ω = 76.67 to 22.38 to 12.14
Image height = 14.20 to 14.20 to 14.20
Total length = 131.591 to 170.738 to 191.244

Surface number Curvature radius Surface spacing Abbe number Refractive index
1 127.1007 2.0000 23.78 1.846660
2 68.0866 7.4621 70.23 1.487490
3 -789.7221 0.1000
4 58.5100 5.7779 50.88 1.658441
5 205.2524 (d5)
* 6 155.8421 0.1500 38.09 1.553890
7 91.9644 1.2000 42.72 1.834807
8 14.4078 6.8486
9 -33.7631 1.0000 46.63 1.816000
10 52.3310 0.1000
11 35.0000 4.0788 23.78 1.846660
12 -35.3134 1.1463
13 -20.8608 1.0000 47.38 1.788000
14 -46.1994 (d14)
15 ∞ 0.5000 (Aperture stop S)
16 33.3603 2.9346 64.19 1.516798
17 -42.6922 0.1000
18 24.9127 3.3760 81.61 1.497000
19 -38.2884 1.0000 32.35 1.850260
20 573.0840 3.0000
* 21 -37.4522 0.1000 38.09 1.553890
22 -37.6846 1.0000 64.10 1.516800
23 31.2120 1.6802 27.51 1.755199
24 50.0206 1.5000
25 ∞ (d25) (Flare cut aperture)
* 26 64.5178 3.2899 64.03 1.516120
27 -35.6588 0.5000
28 500.0000 2.0396 70.41 1.487490
29 -78.8097 1.3000 32.35 1.850 260
30 50.8610 0.8683
31 140.0573 3.6434 70.41 1.487490
32 -29.2586 (Bf)

[Lens focal length and moving distance]
f1 = 98.935
f2 = -15.109
f3 = 44.583
f4 = 46.104
Δd1 = 59.653
Δd3 = 38.373

  In the second embodiment, the lens surfaces of the sixth surface, the twenty-first surface, and the twenty-sixth surface are formed in an aspherical shape. Table 6 below shows the aspheric data, that is, the values of the conic constant κ and the aspheric constants A4 to A10.

(Table 6)
κ A4 A6 A8 A10
6th surface 1.0000 1.80020E-05 -3.75590E-08 6.82670E-11 8.79960E-14
21st surface 9.7304 3.14860E-05 5.10490E-08 8.64750E-10 0.00000E + 00
26th surface -0.2727 -3.48330E-05 2.53290E-08 -1.86100E-10 0.00000E + 00

  In the second embodiment, the axial air distance d5 between the first lens group G1 and the second lens group G2, the axial air distance d14 between the second lens group G2 and the third lens group G3, and the third lens group G3. The on-axis air gap d25 and the back focus Bf between the first lens group G4 and the fourth lens group G4 change during zooming. Table 7 below shows variable intervals at the respective focal lengths in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

(Table 7)
Wide angle end Intermediate focal length Telephoto end
f 18.500 70.000 131.000
d5 2.070 33.852 48.965
d14 27.416 7.230 1.800
d25 6.418 2.049 1.450
Bf 37.991 69.912 81.333

  Table 8 below shows values corresponding to the conditional expressions in the second embodiment.

(Table 8)
(1) (Lw · fw) / (Δd1 · ft) = 0.312
(2) (Lw · fw) / (Δd3 · ft) = 0.484
(3) f3 / fw = 2.410
(4) f1 / fw = 5.348
(5) f3 / ft = 0.340
(6) f3 / f4 = 0.967
(7) Bfw / fw = 2.054

  FIG. 6A is an aberration diagram in the infinite focus state in the wide-angle end state of FIG. 6A, FIG. 7 is an aberration diagram in the infinite focus state in the intermediate focal length state, and FIG. FIG. 8A shows an aberration diagram of the in-focus state at infinity. Further, FIG. 6B shows a coma aberration diagram when the shake correction is performed with respect to the rotational shake of 0.60 ° in the infinity photographing state at the wide-angle end state of the second embodiment, and the telephoto of the second embodiment. FIG. 8B shows a coma aberration diagram when blur correction is performed with respect to 0.27 ° rotational blur in the infinity shooting state in the end state. As is apparent from the respective aberration diagrams, in the second example, it is understood that various aberrations are favorably corrected in each focal length state from the wide-angle end state to the telephoto end state, and excellent imaging performance is obtained.

[Third embodiment]
FIG. 9 is a diagram illustrating a configuration of the variable magnification optical system ZL3 according to the third example. In the variable magnification optical system ZL3 of FIG. 9, the first lens group G1 includes, in order from the object side, a cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12, and an object It comprises a positive meniscus lens L13 having a convex surface on the side. The second lens group G2, in order from the object side, includes a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a negative surface having a concave surface directed toward the object side. The negative meniscus lens L21 including the meniscus lens L24 and positioned closest to the object side of the second lens group G2 is an aspherical lens in which an aspherical surface is formed by providing a resin layer on the glass lens surface on the object side. The third lens group G3a of the third lens group G3 includes, in order from the object side, a biconvex positive lens L31, and a biconvex positive lens L32 and a negative meniscus lens L33 having a concave surface facing the object side. Consists of lenses. The third lens group G3b of the third lens group G3 includes, in order from the object side, a cemented lens of a biconcave negative lens L34 and a positive meniscus lens L35 having a convex surface facing the object side. The third lens group G3b The biconcave negative lens L34 located closest to the object side is an aspherical lens in which an aspherical surface is formed by providing a resin layer on the glass lens surface on the object side. The fourth lens group G4 has, in order from the object side, a biconvex positive lens L41, a cemented lens of a biconvex positive lens L42 and a biconcave negative lens L43, and a convex surface directed toward the image side. The biconvex positive lens L41, which includes the positive meniscus lens L44 and is located closest to the object side in the fourth lens group G4, is an aspheric lens having an aspheric lens surface on the object side.

  In the wide-angle end state of the third embodiment, the image stabilization correction coefficient is 1.000 and the focal length is 18.50 (mm), so the third b for correcting the rotation blur of 0.60 °. The moving amount of the lens group G3b is 0.194 (mm). Further, in the telephoto end state of the third embodiment, the image stabilization correction coefficient is 1.797 and the focal length is 105.00 (mm), so that the rotation blur of 0.30 ° is corrected. The moving amount of the third lens group G3b is 0.306 (mm).

  Table 9 below lists values of specifications of the third example.

(Table 9)
Wide angle end Intermediate focal length Telephoto end
f = 18.50 to 65.00 to 105.00
FNO = 3.52 to 5.13 to 5.74
2ω = 78.26 to 24.33 to 15.24
Image height = 14.20 to 14.20 to 14.20
Total length = 131.517 to 163.372 to 180.515

Surface number Curvature radius Surface spacing Abbe number Refractive index
1 134.7329 2.0000 23.78 1.846660
2 68.5573 6.5591 70.23 1.487490
3 -633.6719 0.1000
4 53.4321 5.1596 50.88 1.658441
5 189.7811 (d5)
* 6 182.9094 0.1500 38.09 1.553890
7 103.7413 1.2000 46.57 1.804000
8 14.5151 6.9532
9 -31.1324 1.0000 39.58 1.804398
10 49.3719 0.1000
11 35.0000 4.2243 23.78 1.846660
12 -32.7363 1.0764
13 -20.5005 1.0000 47.38 1.788000
14 -44.0388 (d14)
15 ∞ 0.5000 (Aperture stop S)
16 40.8340 2.7262 64.19 1.516798
17 -38.4648 0.1000
18 27.3585 3.2934 81.61 1.497000
19 -32.0272 1.0000 32.35 1.850 260
20 -179.9291 3.0000
* 21 -35.4208 0.1000 38.09 1.553890
22 -35.7415 1.0000 64.10 1.516800
23 32.9221 1.5617 23.78 1.846660
24 45.6074 1.5000
25 ∞ (d25) (Flare cut aperture)
* 26 162.6073 3.2000 64.03 1.516120
27 -34.1598 0.5000
28 90.0000 2.9026 60.67 1.563839
29 -53.8564 1.3000 32.35 1.850 260
30 61.1613 1.3249
31 -309.5498 3.6147 70.41 1.487490
32 -25.1830 (Bf)

[Lens focal length and moving distance]
f1 = 93.094
f2 = -15.473
f3 = 47.005
f4 = 44.335
Δd1 = 48.998
Δd3 = 37.545

  In the third embodiment, the lens surfaces of the sixth surface, the twenty-first surface, and the twenty-sixth surface are formed in an aspherical shape. Table 10 below shows the aspheric data, that is, the values of the conic constant κ and the aspheric constants A4 to A10.

(Table 10)
κ A4 A6 A8 A10
6th surface 1.0000 1.65830E-05 -3.43150E-08 5.65390E-11 1.12030E-13
Side 21 8.3238 3.21570E-05 7.35370E-08 5.56910E-10 0.00000E + 00
26th surface 19.1791 -3.00450E-05 0.00000E + 00 0.00000E + 00 0.00000E + 00

  In the third example, the axial air distance d5 between the first lens group G1 and the second lens group G2, the axial air distance d14 between the second lens group G2 and the third lens group G3, and the third lens group G3. The on-axis air gap d25 and the back focus Bf between the first lens group G4 and the fourth lens group G4 change during zooming. Table 11 below shows variable intervals at the respective focal lengths in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

(Table 11)
Wide angle end Intermediate focal length Telephoto end
f 18.500 65.000 105.000
d5 2.098 28.005 39.057
d14 27.305 6.199 1.800
d25 6.951 2.079 1.450
Bf 38.017 69.944 81.062

  Table 12 below shows values corresponding to the conditional expressions in the third embodiment.

(Table 12)
(1) (Lw · fw) / (Δd1 · ft) = 0.473
(2) (Lw · fw) / (Δd3 · ft) = 0.617
(3) f3 / fw = 2.541
(4) f1 / fw = 5.032
(5) f3 / ft = 0.448
(6) f3 / f4 = 1.060
(7) Bfw / fw = 2.055

  FIG. 10A shows an aberration diagram in the infinite focus state in the wide-angle end state of this third embodiment, FIG. 11 shows an aberration diagram in the infinite focus state in the intermediate focal length state, and FIG. FIG. 12A shows an aberration diagram in the infinitely focused state. FIG. 10B shows a coma aberration diagram when the blur correction is performed with respect to the rotational shake of 0.60 ° in the infinity photographing state at the wide-angle end state of the third example. FIG. 12B shows a coma aberration diagram when blur correction is performed with respect to a rotational blur of 0.30 ° in the infinity photographing state at the telephoto end state. As is apparent from the respective aberration diagrams, in the third example, it is understood that various aberrations are favorably corrected in each focal length state from the wide-angle end state to the telephoto end state, and excellent imaging performance is obtained.

[Fourth embodiment]
FIG. 13 is a diagram showing a configuration of the variable magnification optical system ZL4 according to the fourth example. In the variable magnification optical system ZL4 of FIG. 13, the first lens group G1 includes, in order from the object side, a cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12, and an object It comprises a positive meniscus lens L13 having a convex surface on the side. The second lens group G2, in order from the object side, includes a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a negative surface having a concave surface directed toward the object side. The negative meniscus lens L21 including the meniscus lens L24 and positioned closest to the object side of the second lens group G2 is an aspherical lens in which an aspherical surface is formed by providing a resin layer on the glass lens surface on the object side. The third lens group G3a of the third lens group G3 includes, in order from the object side, a biconvex positive lens L31, and a biconvex positive lens L32 and a negative meniscus lens L33 having a concave surface facing the object side. Consists of lenses. The third lens group G3b of the third lens group G3 includes, in order from the object side, a cemented lens of a biconcave negative lens L34 and a positive meniscus lens L35 having a convex surface facing the object side. The third lens group G3b The biconcave negative lens L34 located closest to the object side is an aspheric lens in which an aspheric surface is formed by providing a resin layer on the glass lens surface on the object side. The fourth lens group G4 has, in order from the object side, a biconvex positive lens L41, a cemented lens of a biconvex positive lens L42 and a biconcave negative lens L43, and a convex surface directed toward the image side. The positive meniscus lens L41, which includes the positive meniscus lens L44 and is located closest to the object side of the fourth lens group G4, is an aspheric lens having an aspheric lens surface on the object side.

  In the fourth embodiment, in the wide-angle end state, the image stabilization correction coefficient is 1.000 and the focal length is 18.50 (mm). Therefore, the third b for correcting the rotation blur of 0.60 °. The moving amount of the lens group G3b is 0.194 (mm). Further, in the telephoto end state of the fourth embodiment, the image stabilization correction coefficient is 1.815 and the focal length is 105.00 (mm), so that the rotation blur of 0.30 ° is corrected. The amount of movement of the third lens group G3b is 0.303 (mm).

  Table 13 below provides values of specifications of the fourth example.

(Table 13)
Wide angle end Intermediate focal length Telephoto end
f = 18.50 to 65.00 to 105.00
FNO = 3.51 to 5.10 to 5.79
2ω = 78.26 to 24.32 to 15.24
Image height = 14.20 to 14.20 to 14.20
Total length = 131.550 to 167.168 to 186.160

Surface number Curvature radius Surface spacing Abbe number Refractive index
1 141.6433 2.0000 23.78 1.846660
2 72.6601 6.3104 70.23 1.487490
3 -931.1892 0.1000
4 56.0747 4.9593 50.88 1.658441
5 191.8276 (d5)
* 6 114.9754 0.1500 38.09 1.553890
7 73.7929 1.2000 46.57 1.804000
8 14.5527 7.7748
9 -30.0224 1.0000 39.58 1.804398
10 47.7644 0.1000
11 35.0000 4.2146 23.78 1.846660
12 -32.9530 1.1617
13 -19.9264 1.0000 47.38 1.788000
14 -42.0535 (d14)
15 ∞ 0.5000 (Aperture stop S)
16 44.6991 2.7606 64.19 1.516798
17 -34.8394 0.1000
18 28.4488 3.3997 81.61 1.497000
19 -28.2321 1.0000 32.35 1.850260
20 -119.4787 3.0000
* 21 -35.4985 0.1000 38.09 1.553890
22 -35.7580 1.0000 64.10 1.516800
23 29.9881 1.6238 23.78 1.846660
24 43.5041 1.5000
25 ∞ (d25) (Flare cut aperture)
* 26 232.2663 3.2000 64.03 1.516120
27 -32.1872 0.5000
28 90.0000 2.9876 60.67 1.563839
29 -49.4149 1.3000 32.35 1.850 260
30 60.9686 1.3389
31 -285.1808 3.6098 70.40 1.487490
32 -25.0178 (Bf)

[Lens focal length and moving distance]
f1 = 100.639
f2 = -15.490
f3 = 45.735
f4 = 45.228
Δd1 = 54.610
Δd3 = 38.792

  In the fourth embodiment, the lens surfaces of the sixth surface, the twenty-first surface, and the twenty-sixth surface are formed in an aspherical shape. Table 14 below shows the aspheric data, that is, the values of the conic constant κ and the aspheric constants A4 to A10.

(Table 14)
κ A4 A6 A8 A10
6th surface 1.0000 1.52370E-05 -2.25400E-08 5.16300E-12 2.25290E-13
Side 21 8.6305 3.26180E-05 6.91300E-08 6.92310E-10 0.00000E + 00
Side 26 -183.0712 -2.58810E-05 0.00000E + 00 0.00000E + 00 0.00000E + 00

  In the fourth embodiment, the axial air distance d5 between the first lens group G1 and the second lens group G2, the axial air distance d14 between the second lens group G2 and the third lens group G3, and the third lens group G3. The on-axis air gap d25 and the back focus Bf between the first lens group G4 and the fourth lens group G4 change during zooming. Table 15 below shows variable intervals at the respective focal lengths in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

(Table 15)
Wide angle end Intermediate focal length Telephoto end
f 18.500 65.000 105.000
d5 2.113 31.473 42.677
d14 26.546 6.189 1.800
d25 6.950 2.036 1.450
Bf 38.050 69.578 82.342

  Table 16 below shows values corresponding to the conditional expressions in the fourth embodiment.

(Table 16)
(1) (Lw · fw) / (Δd1 · ft) = 0.424
(2) (Lw · fw) / (Δd3 · ft) = 0.598
(3) f3 / fw = 2.472
(4) f1 / fw = 5.440
(5) f3 / ft = 0.436
(6) f3 / f4 = 1.010
(7) Bfw / fw = 2.057

  FIG. 14A shows an aberration diagram in the infinite focus state in the wide-angle end state of this fourth embodiment, FIG. 15 shows an aberration diagram in the infinite focus state in the intermediate focal length state, and FIG. FIG. 16A shows an aberration diagram of the infinitely focused state. Further, FIG. 14B shows a coma aberration diagram when the shake correction is performed with respect to the rotational shake of 0.60 ° in the infinity photographing state at the wide-angle end state of the fourth embodiment. FIG. 16B shows a coma aberration diagram when blur correction is performed with respect to 0.30 ° rotational blur in the infinity photographing state at the telephoto end state. As is apparent from the respective aberration diagrams, in the fourth example, it is understood that various aberrations are favorably corrected in each focal length state from the wide-angle end state to the telephoto end state, and excellent imaging performance is obtained.

[Fifth embodiment]
FIG. 17 is a diagram showing a configuration of a variable magnification optical system ZL5 according to the fifth example. In the variable magnification optical system ZL5 of FIG. 17, the first lens group G1 includes, in order from the object side, a cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12, and an object It comprises a positive meniscus lens L13 having a convex surface on the side. The second lens group G2, in order from the object side, includes a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a negative surface having a concave surface directed toward the object side. The negative meniscus lens L21 including the meniscus lens L24 and positioned closest to the object side of the second lens group G2 is an aspherical lens in which an aspherical surface is formed by providing a resin layer on the glass lens surface on the object side. The third lens group G3a of the third lens group G3 includes, in order from the object side, a biconvex positive lens L31, and a cemented lens of a biconvex positive lens L32 and a biconcave negative lens L33. The The third lens group G3b of the third lens group G3 includes, in order from the object side, a cemented lens of a biconcave negative lens L34 and a positive meniscus lens L35 having a convex surface facing the object side. The third lens group G3b The biconcave negative lens L34 located closest to the object side is an aspheric lens in which an aspheric surface is formed by providing a resin layer on the glass lens surface on the object side. The fourth lens group G4 includes, in order from the object side, a biconvex positive lens L41, a cemented lens of a positive meniscus lens L42 having a convex surface facing the image surface and a biconcave negative lens L43, and a biconvex shape. The biconvex positive lens L41, which is composed of the positive lens L44 and is located closest to the object side of the fourth lens group G4, is an aspheric lens having an aspheric lens surface on the object side.

  In the fifth embodiment, in the wide-angle end state, the image stabilization correction coefficient is 0.999 and the focal length is 18.50 (mm), so the third b for correcting the rotation blur of 0.60 °. The moving amount of the lens group G3b is 0.194 (mm). In the telephoto end state of the fifth embodiment, the image stabilization correction coefficient is 1.803 and the focal length is 131.00 (mm). The amount of movement of the third lens group G3b is 0.342 (mm).

  Table 17 below provides values of specifications of the fifth example.

(Table 17)
Wide angle end Intermediate focal length Telephoto end
f = 18.50 to 70.00 to 131.00
FNO = 3.47 to 4.83 to 5.77
2ω = 78.07 to 22.38 to 12.19
Image height = 14.20 to 14.20 to 14.20
Total length = 134.867 to 175.840 to 197.401

Surface number Curvature radius Surface spacing Abbe number Refractive index
1 131.8145 2.0000 32.35 1.850 260
2 66.7419 7.5709 81.61 1.497000
3 -1267.3183 0.1000
4 60.4311 6.4106 65.47 1.603000
5 271.9391 (d5)
* 6 280.2980 0.1500 38.09 1.553890
7 116.0121 1.2000 46.63 1.816000
8 14.8328 6.7543
9 -31.2380 1.0000 46.63 1.816000
10 55.8688 0.1000
11 37.6211 3.7843 23.78 1.846660
12 -42.5664 1.8254
13 -17.8616 1.0000 47.38 1.788000
14 -25.2572 (d14)
15 ∞ 0.5000 (Aperture stop S)
16 35.4547 2.5444 65.47 1.603000
17 -49.0607 0.1000
18 27.6369 3.0607 81.61 1.497000
19 -35.3391 1.0000 32.35 1.850 260
20 849.7261 3.0000
* 21 -39.3954 0.1000 38.09 1.553890
22 -39.5271 1.0000 64.12 1.516800
23 25.0000 1.4590 27.51 1.755200
24 40.3853 1.5000
25 ∞ (d25) (Flare cut aperture)
* 26 57.1912 3.3608 70.45 1.487490
27 -26.1998 0.5000
28 -31341.9590 3.4990 70.45 1.487490
29 -19.9000 1.4000 44.79 1.744000
30 48.2777 0.9461
31 141.0745 3.5724 70.45 1.487490
32 -25.6598 (Bf)

[Lens focal length and moving distance]
f1 = 107.049
f2 = -15.981
f3 = 47.794
f4 = 47.275
Δd1 = 62.534
Δd3 = 38.119

  In the fifth embodiment, the lens surfaces of the sixth surface, the twenty-first surface, and the twenty-sixth surface are formed in an aspherical shape. Table 18 below shows aspheric data, that is, the values of the conic constant κ and the aspheric constants A4 to A10.

(Table 18)
κ A4 A6 A8 A10
6th surface 1.0000 1.98880E-05 -3.90400E-08 8.42890E-11 1.34030E-13
21st surface 6.5091 2.30430E-05 -1.51290E-08 5.59780E-10 -2.19660E-12
26th -67.0889 1.07570E-05 -3.20900E-07 2.32710E-09 -8.11680E-12

  In the fifth embodiment, the axial air distance d5 between the first lens group G1 and the second lens group G2, the axial air distance d14 between the second lens group G2 and the third lens group G3, and the third lens group G3. The on-axis air gap d25 and the back focus Bf between the first lens group G4 and the fourth lens group G4 change during zooming. Table 19 below shows variable intervals at each focal length in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

(Table 19)
Wide angle end Intermediate focal length Telephoto end
f 18.500 69.998 130.995
d5 2.070 41.366 53.610
d14 29.519 9.146 2.394
d25 5.843 1.767 1.000
Bf 37.997 64.123 80.959

  Table 20 below shows values corresponding to the conditional expressions in the fifth embodiment.

(Table 20)
(1) (Lw · fw) / (Δd1 · ft) = 0.305
(2) (Lw · fw) / (Δd3 · ft) = 0.500
(3) f3 / fw = 2.583
(4) f1 / fw = 5.786
(5) f3 / ft = 0.365
(6) f3 / f4 = 1.010
(7) Bfw / fw = 2.054

  FIG. 18A shows an aberration diagram in the infinite focus state in the wide-angle end state of this fifth embodiment, FIG. 19 shows an aberration diagram in the infinite focus state in the intermediate focal length state, and FIG. FIG. 20A shows an aberration diagram of the infinitely focused state. FIG. 18B shows a coma aberration diagram when the blur correction is performed with respect to the rotational blur of 0.60 ° in the infinity photographing state at the wide-angle end state of the fifth example. FIG. 20B shows a coma aberration diagram when blur correction is performed for 0.27 ° rotational blur in the infinity shooting state at the telephoto end state. As is apparent from each aberration diagram, in the fifth example, it is understood that various aberrations are well corrected in each focal length state from the wide-angle end state to the telephoto end state, and excellent imaging performance is obtained.

It is sectional drawing which shows the structure of the variable magnification optical system by 1st Example. FIG. 4A is a diagram illustrating various aberrations in the infinitely focused state according to the first example, FIG. 5A is a diagram illustrating various aberrations in the wide-angle end state, and FIG. FIG. 7 is a coma aberration diagram when shake correction is performed for rotational shake. FIG. 6 is an aberration diagram in an infinitely focused state at an intermediate focal length state in the first example. FIG. 4A is a diagram illustrating various aberrations in the infinitely focused state according to the first embodiment, FIG. 5A is a diagram illustrating various aberrations in the telephoto end state, and FIG. 5B is 0.27 ° in the infinity photographing state in the telephoto end state. FIG. 7 is a coma aberration diagram when shake correction is performed for rotational shake. It is sectional drawing which shows the structure of the variable magnification optical system by 2nd Example. FIG. 7A is a diagram illustrating various aberrations in the infinitely focused state according to the second embodiment, FIG. 9A is a diagram illustrating various aberrations in the wide-angle end state, and FIG. 9B is 0.60 ° in the infinity photographing state in the wide-angle end state. FIG. 7 is a coma aberration diagram when shake correction is performed for rotational shake. It is an aberration diagram of the infinite focus state in the intermediate focal length state of the second embodiment. FIG. 7A is a diagram illustrating various aberrations in the infinite focus state according to the second embodiment, FIG. 9A is a diagram illustrating various aberrations in the telephoto end state, and FIG. 9B is 0.27 ° in the infinity photographing state in the telephoto end state. FIG. 7 is a coma aberration diagram when shake correction is performed for rotational shake. It is sectional drawing which shows the structure of the variable magnification optical system by 3rd Example. FIG. 6A is a diagram illustrating various aberrations in the infinite focus state according to the third example, FIG. 6A is a diagram illustrating various aberrations in the wide-angle end state, and FIG. FIG. 7 is a coma aberration diagram when shake correction is performed for rotational shake. It is an aberration diagram of the infinite focus state in the intermediate focal length state of the third embodiment. FIG. 6A is a diagram illustrating various aberrations in the infinitely focused state according to the third embodiment, FIG. 9A is a diagram illustrating various aberrations in the telephoto end state, and FIG. 9B is 0.30 ° in the infinity photographing state in the telephoto end state. FIG. 7 is a coma aberration diagram when shake correction is performed for rotational shake. It is sectional drawing which shows the structure of the variable magnification optical system by 4th Example. FIG. 6A is a diagram illustrating various aberrations in the infinitely focused state according to the fourth example, FIG. 6A is a diagram illustrating various aberrations in the wide-angle end state, and FIG. FIG. 7 is a coma aberration diagram when shake correction is performed for rotational shake. FIG. 10 is an aberration diagram in an infinitely focused state at an intermediate focal length state in the fourth example. FIG. 7A is a diagram illustrating various aberrations in the infinite focus state according to the fourth embodiment, FIG. 9A is a diagram illustrating various aberrations in the telephoto end state, and FIG. 9B is 0.30 ° in the infinity photographing state in the telephoto end state. FIG. 7 is a coma aberration diagram when shake correction is performed for rotational shake. It is sectional drawing which shows the structure of the variable magnification optical system by 5th Example. FIG. 9A is a diagram illustrating various aberrations in the infinitely focused state according to the fifth example, FIG. 10A is a diagram illustrating various aberrations in the wide-angle end state, and FIG. FIG. 7 is a coma aberration diagram when shake correction is performed for rotational shake. FIG. 10 is an aberration diagram in an infinitely focused state at an intermediate focal length state in the fifth example. FIG. 7A is a diagram illustrating various aberrations in the infinitely focused state according to the fifth example, FIG. 9A is a diagram illustrating various aberrations in the telephoto end state, and FIG. 9B is 0.27 ° in the infinity photographing state in the telephoto end state. FIG. 7 is a coma aberration diagram when shake correction is performed for rotational shake. 1 is a cross-sectional view of a digital single-lens reflex camera equipped with a variable magnification optical system according to the present invention.

Explanation of symbols

ZL (ZL1 to ZL5) Variable magnification optical system G1 First lens group G2 Second lens group G3 Third lens group G3a 3a lens group G3b 3b lens group G4 Fourth lens group 1 Digital single lens reflex camera (optical equipment)

Claims (9)

From the object side,
A first lens group having a positive refractive power;
A second lens group having negative refractive power;
A third lens group having positive refractive power;
It consists of a fourth lens group having positive refractive power,
When the lens position state changes from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group increases, and the distance between the second lens group and the third lens group is The distance between the third lens group and the fourth lens group changes,
The third lens group includes, in order from the object side, a 3a lens group having a positive refractive power and a 3b lens group having a negative refractive power, and the 3b lens group is orthogonal to the optical axis. Configured to move in the direction to
The third lens group is composed of a cemented lens in which, in order from the object side, a biconcave lens and a positive meniscus lens having a convex surface facing the object side are cemented,
The focal length of the entire system in the wide-angle end state is fw, the focal length of the entire system in the telephoto end state is ft, the focal length of the third lens group is f3, and the lens position state is from the wide-angle end state to the telephoto end state. The moving distance on the optical axis of the first lens group when changing is Δd1, and the moving distance on the optical axis of the third lens group when the lens position is changed from the wide-angle end state to the telephoto end state is Δd3. When the total length in the wide-angle end state is Lw, the following expression 0.15 <(Lw · fw) / (Δd1 · ft) <0.58
0.42 <(Lw · fw) / (Δd3 · ft) <0.90
2.20 <f3 / fw <4.50
Variable magnification optical system that satisfies the above conditions. When the focal length of the first lens group is f1, the following expression 3.50 <f1 / fw <8.00
2. The variable magnification optical system according to claim 1 , wherein When the lens position state from the wide-angle end state to the telephoto end state changes, the variable magnification optical system according to claim 1 or 2, and the third lens group and the fourth lens group moves toward the object. The zoom optical system according to any one of claims 1 to 3 , wherein the first lens group moves in the object direction when the lens position state changes from the wide-angle end state to the telephoto end state. The following formula 0.30 <f3 / ft <1.00
The zoom lens system according to any one of claims 1 to 4, which satisfies the following condition. 2. The structure according to claim 1, wherein an interval between the third lens group and the fourth lens group in the wide-angle end state is larger than an interval between the third lens group and the fourth lens group in the telephoto end state . 5. The zoom optical system according to any one of 5 above. When the focal length of the fourth lens group is f4 and the back focus in the wide-angle end state is Bfw, the following expression 0.80 <f3 / f4 <1.60
1.90 <Bfw / fw <3.00
The zoom optical system according to any one of claims 1 to 6, which satisfies the following condition. The variable magnification optical system according to any one of claims 1 to 7, wherein a lens surface closest to the object side of the third b lens group is formed in an aspherical shape. Optical apparatus including the variable magnification optical system according to any one of claims 1-8.

Images