JP2011221422A - Zoom optical system, optical apparatus equipped with zoom optical system and method for manufacturing zoom optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom optical system capable of obtaining excellent optical performance, an optical apparatus equipped with the zoom optical system, and a method for manufacturing the zoom optical system.SOLUTION: The zoom optical system ZL mounted on a digital single lens reflex camera 1 and the like includes, in order from an object side: a first lens group G1 having positive refractive power; a second lens group G2 having negative refractive power; a third lens group G3 having positive refractive power; a fourth lens group G4 having negative refractive power; and a fifth lens group G5 having positive refractive power. The zoom optical system ZL moves in such a way that the distance between the fourth lens group G4 and the fifth lens group G5 is decreased, when zooming from a wide-angle end state to a telephoto end state.

Description

  The present invention relates to a variable magnification optical system, an optical apparatus including the variable magnification optical system, and a method for manufacturing the variable magnification optical system.

  Conventionally, a variable magnification optical system suitable for a photographic camera, an electronic still camera, a video camera, and the like has been proposed (see, for example, Patent Document 1).

JP-A-8-94932

  However, the conventional variable magnification optical system has a problem that it cannot achieve good optical performance.

  The present invention has been made in view of such problems, and provides a variable magnification optical system having good optical performance, an optical apparatus including the variable magnification optical system, and a method for manufacturing the variable magnification optical system. With the goal.

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 power, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power, and upon zooming from the wide-angle end state to the telephoto end state, The distance between the fourth lens group and the fifth lens group is reduced and moved. The focal length of the first lens group is f1, the focal length of the second lens group is f2, and the focal point of the third lens group. When the distance is f3 and the focal length of the entire system in the wide-angle end state is fw, the following expression 0.10 <f3 / (− f2) <1.35
3.0 <f1 / fw <20.0
Satisfy the conditions.

Further, in this zoom optical system, upon zooming from the wide-angle end state to the telephoto end state, the air interval between the fourth lens group and the fifth lens group in the wide-angle end state is d4w, and the fourth lens group and the fourth lens group When the distance between the air in the telephoto end state with the five lens groups is d4t, the following formula (d4w−d4t) / fw> 0.00

Further, in this zoom optical system, when the focal length of the fourth lens group is f4, the following formula 0.50 <f3 / (− f4) <1.50
It is preferable to satisfy the following conditions.

The variable magnification optical system has the following formula 0.58 <(− f2) / fw <0.95.
It is preferable to satisfy the following conditions.

Further, in this variable power optical system, when the focal length of the fourth lens group is f4, the following formula 0.40 <f2 / f4 <1.20
It is preferable to satisfy the following conditions.

Further, in this variable magnification optical system, when the focal length of the first lens group is f1, the following expression 3.0 <f1 / f3 <6.0
It is preferable to satisfy the following conditions.

  In the zoom optical system, it is preferable that at least a part of the second lens group moves on the optical axis when focusing from infinity to a short-distance object point.

  In this zoom optical system, it is preferable that the lens surface closest to the image side of the second lens group has an aspherical shape.

  In the zoom optical system, it is preferable that the fourth lens group has at least one cemented lens.

  Further, in the zoom optical system, when zooming 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 second lens group and the third lens group It is preferable that the lens groups move so that the distance decreases, the distance between the third lens group and the fourth lens group increases, and the distance between the fourth lens group and the fifth lens group decreases.

  In this zoom optical system, it is preferable that at least a part of the fourth lens group moves so as to have a component in a direction orthogonal to the optical axis.

  In this variable magnification optical system, it is preferable that the most object side lens surface of the second lens group has an aspherical shape.

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

In addition, in the manufacturing method of the variable magnification optical system according to the present invention, 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 first lens group having a positive refractive power. A method of manufacturing a variable magnification optical system having three lens groups, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power, from a wide-angle end state to a telephoto end state Is arranged such that the distance between the fourth lens group and the fifth lens group is reduced and moved, the focal length of the first lens group is f1, the focal length of the second lens group is f2, When the focal length of the three lens units is f3 and the focal length of the entire system in the wide-angle end state is fw, the following expression 0.10 <f3 / (− f2) <1.35
3.0 <f1 / fw <20.0
Arrange to satisfy the conditions of

  When the variable magnification optical system according to the present invention, the optical apparatus including the variable magnification optical system, and the method for manufacturing the variable magnification optical system are configured as described above, good optical performance can be obtained.

It is sectional drawing which shows the structure of the variable magnification optical system by 1st Example. FIG. 6 is a diagram illustrating various aberrations in an infinitely focused state according to the first example, (a) is a diagram illustrating various aberrations in a wide-angle end state, (b) is a diagram illustrating aberrations in an intermediate focal length state, and (c) is a diagram illustrating aberrations. It is an aberration diagram in the telephoto end state. It is sectional drawing which shows the structure of the variable magnification optical system by 2nd Example. FIG. 6 is a diagram illustrating various aberrations in the infinitely focused state according to the second embodiment, (a) illustrating various aberrations in the wide-angle end state, (b) various aberration diagrams in the intermediate focal length state, and (c). These are aberration diagrams in the telephoto end state. It is sectional drawing which shows the structure of the variable magnification optical system by 3rd Example. FIG. 6 is a diagram illustrating various aberrations in the infinitely focused state according to the third example, (a) illustrating various aberrations in the wide-angle end state, (b) various aberration diagrams in the intermediate focal length state, and (c). These are aberration diagrams in the telephoto end state. It is sectional drawing which shows the structure of the variable magnification optical system by 4th Example. FIG. 10 is a diagram illustrating all aberrations in the infinitely focused state according to the fourth example, (a) is a diagram illustrating various aberrations in the wide-angle end state, (b) is a diagram illustrating various aberrations in the intermediate focal length state, and (c) These are aberration diagrams in the telephoto end state. It is sectional drawing which shows the structure of the variable magnification optical system by 5th Example. FIG. 10 is a diagram illustrating various aberrations in the infinitely focused state according to the fifth example, (a) illustrating various aberrations in the wide-angle end state, (b) various aberration diagrams in the intermediate focal length state, and (c). These are aberration diagrams in the telephoto end state. 1 is a cross-sectional view of a digital single-lens reflex camera equipped with a variable magnification optical system according to the present embodiment. It is a flowchart for demonstrating the manufacturing method of the variable magnification optical system which concerns on this embodiment.

  Hereinafter, preferred embodiments of the present application will be described with reference to the drawings. First, as shown in FIG. 1, the variable magnification optical system ZL of the present embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power and a second lens group G2 having a negative refractive power. The third lens group G3 having positive refractive power, the fourth lens group G4 having negative refractive power, and the fifth lens group G5 having positive refractive power. With such a configuration, it is possible to satisfactorily correct the aberration of zooming and zooming.

  Further, it is desirable that the zoom optical system ZL of the present embodiment moves so that the distance between the fourth lens group G4 and the fifth lens group G5 is reduced when zooming from the wide-angle end state to the telephoto end state. . With such a configuration, it is possible to satisfactorily correct a predetermined zoom ratio and zooming aberration fluctuation.

  Further, the variable magnification optical system ZL of the present embodiment satisfies the following conditional expression (1) when the focal length of the second lens group G2 is f2 and the focal length of the third lens group G3 is f3. Is desirable.

0.10 <f3 / (− f2) <1.35 (1)

  Conditional expression (1) defines the ratio between the focal length f2 of the second lens group G2 and the focal length f3 of the third lens group G3. The zooming optical system ZL of the present embodiment can achieve good optical performance and a predetermined zooming ratio by satisfying this conditional expression (1). Exceeding the upper limit of conditional expression (1) is not preferable because the refractive power of the second lens group G2 becomes strong and it becomes difficult to correct coma and field curvature at the wide-angle end. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (1) to 1.33. In order to further secure the effect of the present embodiment, it is more preferable to set the upper limit of conditional expression (1) to 1.31. On the other hand, if the lower limit of conditional expression (1) is not reached, the refractive power of the third lens group G3 becomes strong, and it becomes difficult to correct spherical aberration and coma at the telephoto end, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (1) to 0.60. In order to further secure the effect of the present embodiment, it is more preferable to set the lower limit of conditional expression (1) to 1.00.

  The variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (2) when the focal length of the first lens group G1 is f1 and the focal length of the entire system in the wide-angle end state is fw. It is desirable to do.

2.5 <f1 / fw <20.0 (2)

  Conditional expression (2) defines the ratio between the focal length f1 of the first lens group G1 and the focal length fw of the entire system in the wide-angle end state. The zoom optical system ZL according to the present embodiment can achieve good optical performance and a predetermined zoom ratio by satisfying the conditional expression (2). If the upper limit of conditional expression (2) is exceeded, the refractive power of the first lens group G1 becomes weak, the amount of movement increases to obtain a predetermined zoom ratio, and the lens barrel structure becomes large. In order to mitigate this effect, the refractive power of the other group is increased, and correction of spherical aberration and coma at the telephoto end becomes difficult. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (2) to 10.0. In order to further secure the effect of the present embodiment, it is more preferable to set the upper limit of conditional expression (2) to 7.0. On the other hand, if the lower limit value of conditional expression (2) is not reached, the refractive power of the first lens group G1 becomes strong, and correction of coma and spherical aberration at the telephoto end becomes difficult. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (2) to 3.2. In order to further secure the effect of the present embodiment, it is more preferable to set the lower limit of conditional expression (2) to 3.4.

  Further, in the zoom optical system ZL according to the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the air gap in the wide-angle end state between the fourth lens group G4 and the fifth lens group G5 is d4w. When the air gap between the fourth lens group G4 and the fifth lens group G5 in the telephoto end state is d4t and the focal length of the entire system in the wide-angle end state is fw, the following conditional expression (3) is satisfied. It is desirable.

(D4w−d4t) / fw> 0.00 (3)

  Conditional expression (3) defines the amount of change in the air gap between the fourth lens group G4 and the fifth lens group G5 with respect to the focal length fw of the entire system when zooming from the wide-angle end state to the telephoto end state. Is a conditional expression. This zoom optical system ZL can satisfactorily correct aberrations such as a predetermined zoom ratio and field curvature by satisfying conditional expression (3). In order to secure the effect of the present invention, it is preferable to set the upper limit of conditional expression (3) to 0.05. In order to further secure the effect of the present invention, it is preferable to set the upper limit of 0.10 in conditional expression (3).

  In the zoom optical system ZL according to the present embodiment, when the focal length of the third lens group G3 is f3 and the focal length of the fourth lens group G4 is f4, the following conditional expression (4) is satisfied. It is desirable.

0.50 <f3 / (− f4) <1.50 (4)

  Conditional expression (4) defines the ratio between the focal length f4 of the fourth lens group G4 and the focal length f3 of the third lens group G3. The variable magnification optical system ZL of the present embodiment can realize the downsizing of the lens barrel and good optical performance even during camera shake correction by satisfying the conditional expression (4). If the upper limit of conditional expression (4) is exceeded, the refractive power of the fourth lens group G4 becomes strong, and it becomes difficult to correct spherical aberration and coma at the wide-angle end. Further, it is not preferable because it is difficult to simultaneously correct the fluctuation of the curvature of field and the fluctuation of the decentration coma during the camera shake correction. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (4) to 1.10. In order to further secure the effect of the present embodiment, it is more preferable to set the upper limit of conditional expression (4) to 1.00. On the other hand, if the lower limit of conditional expression (4) is not reached, the refractive power of the third lens group G3 becomes strong, and it becomes difficult to correct spherical aberration and coma at the telephoto end, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (4) to 0.60. In order to further secure the effect of the present embodiment, it is more preferable to set the lower limit of conditional expression (4) to 0.70.

  In the variable magnification optical system ZL according to the present embodiment, when the focal length of the second lens group G2 is f2, and the focal length of the entire system in the wide-angle end state is fw, the following conditional expression (5) is satisfied. It is desirable to do.

0.58 <(− f2) / fw <0.95 (5)

  Conditional expression (5) defines the ratio between the focal length f2 of the second lens group G2 and the focal length fw of the entire system in the wide-angle end state. The zooming optical system ZL of the present embodiment can achieve good optical performance and a predetermined zooming ratio by satisfying this conditional expression (5). If the upper limit value of the conditional expression (5) is exceeded, the refractive power of the second lens group G2 becomes weak, and the refractive power of the other groups is strengthened in order to obtain a predetermined zoom ratio, and the spherical surface at the telephoto end. Since correction of aberration and coma becomes difficult, it is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (5) to 1.00. In order to further secure the effect of the present embodiment, it is more preferable to set the upper limit of conditional expression (5) to 0.90. On the other hand, if the lower limit value of conditional expression (5) is not reached, the refractive power of the second lens group G2 becomes strong, and it becomes difficult to correct coma and field curvature at the wide angle end, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (5) to 0.50. In order to further secure the effect of the present embodiment, it is more preferable to set the lower limit of conditional expression (5) to 0.60.

  Further, the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (6) when the focal length of the second lens group G2 is f2 and the focal length of the fourth lens group G4 is f4. It is desirable.

0.40 <f2 / f4 <1.00 (6)

  Conditional expression (6) defines the ratio between the focal length f4 of the fourth lens group G4 and the focal length f2 of the second lens group G2. The zooming optical system ZL of the present embodiment can satisfy the conditional expression (6) to realize good optical performance even during camera shake correction and to ensure a predetermined zooming ratio. If the upper limit value of conditional expression (6) is exceeded, the refractive power of the fourth lens group G4 becomes strong, and it is difficult to simultaneously correct fluctuations in curvature of field at the time of camera shake correction and fluctuations in eccentric coma. This is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (6) to 0.70. In order to further secure the effect of the present embodiment, it is more preferable to set the upper limit value of conditional expression (6) to 0.65. On the other hand, if the lower limit of conditional expression (6) is not reached, the refractive power of the second lens group G2 becomes strong, and it becomes difficult to correct spherical aberration and coma at the telephoto end, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (6) to 0.50. In order to further secure the effect of the present embodiment, it is more preferable to set the lower limit of conditional expression (6) to 0.55.

  Further, the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (7) when the focal length of the first lens group G1 is f1 and the focal length of the third lens group G3 is f3. It is desirable.

3.0 <f1 / f3 <10.0 (7)

  Conditional expression (7) defines the ratio between the focal length f1 of the first lens group G1 and the focal length f3 of the third lens group G3. The zooming optical system ZL of the present embodiment can achieve good optical performance and a predetermined zooming ratio by satisfying this conditional expression (7). Exceeding the upper limit of conditional expression (7) is not preferable because the refractive power of the third lens group G3 becomes strong and it becomes difficult to correct spherical aberration and coma at the telephoto end. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (7) to 8.0. In order to further secure the effect of the present embodiment, it is more preferable to set the upper limit of conditional expression (7) to 6.0. On the other hand, if the lower limit of conditional expression (7) is not reached, the refractive power of the first lens group G1 will become strong, and it will be difficult to correct spherical aberration at the telephoto end. Further, the deterioration of lateral chromatic aberration at the wide-angle end becomes remarkable, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (7) to 3.5. In order to further secure the effect of the present embodiment, it is more preferable to set the lower limit of conditional expression (7) to 4.0.

  In the zoom optical system ZL according to this embodiment, it is desirable that at least a part of the second lens group G2 moves on the optical axis when focusing from infinity to a short-distance object point. With such a configuration, it is possible to satisfactorily correct aberration variations in downsizing and focusing of the lens barrel.

  In the zoom optical system ZL according to the present embodiment, it is desirable that the most image side lens surface of the second lens group G2 has an aspherical shape. With this configuration, spherical aberration at the telephoto end can be corrected well.

  In the zoom optical system ZL according to this embodiment, it is desirable that the fourth lens group G4 has at least one cemented lens. With this configuration, it is possible to satisfactorily correct chromatic aberration fluctuations during camera shake correction.

  Further, in the zoom optical system ZL according to the present embodiment, when zooming 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 The distance between G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 increases, and the distance between the fourth lens group G4 and the fifth lens group G5 decreases. In addition, it is desirable for each lens group to move. With this configuration, it is possible to ensure a predetermined zoom ratio while effectively correcting variations in spherical aberration and field curvature during zooming.

  In the zoom optical system ZL according to this embodiment, it is desirable that at least a part of the fourth lens group G4 moves so as to have a component in a direction orthogonal to the optical axis. With this configuration, it is possible to simultaneously correct the fluctuation of the curvature of field and the fluctuation of the eccentric coma aberration during camera shake correction while reducing the size of the lens barrel.

  In the zoom optical system ZL according to this embodiment, it is desirable that the lens surface closest to the object side of the second lens group G2 has an aspherical shape. With this configuration, it is possible to satisfactorily correct the curvature of field and distortion at the wide-angle end.

  FIG. 11 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 condensed by a variable magnification optical system 2 (variable magnification optical system ZL) and imaged on a focusing screen 4 via a 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.

  When the release button (not shown) is pressed by the photographer, the quick return mirror 3 is retracted out of the optical path, and the light of the object (subject) (not shown) collected by the zoom optical system 2 is reflected on the image sensor 7. A subject image is formed on the screen. 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. Note that the camera 1 shown in FIG. 11 may hold the variable magnification optical system ZL in a detachable 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.

  The contents described below can be appropriately adopted as long as the optical performance is not impaired.

  First, in the above description and the embodiments described below, the five-group configuration is shown. However, the above-described configuration conditions and the like can be applied to other group configurations such as the sixth group and the seventh group. Further, a configuration in which a lens or a lens group is added to the most object side, or a configuration in which a lens or a lens group is added to the most image side may be used. The lens group refers to a portion having at least one lens separated by an air interval that changes during zooming.

  In addition, a single lens group or a plurality of lens groups, or a partial lens group may be moved along the optical axis 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, it is desirable that at least a part of the second lens group G2 is a focusing lens group.

  Image stabilization that corrects image blur caused by camera shake by moving the lens group or partial lens group so as to have a component perpendicular to the optical axis, or by rotating (swinging) the lens group or partial lens group in the in-plane direction including the optical axis It may be a lens group. In particular, it is preferable that at least a part of the fourth lens group G4 is an anti-vibration lens group.

  Further, the lens surface may be formed as a spherical surface, a flat surface, or an aspheric surface. It is preferable that the lens surface is a spherical surface or a flat surface because lens processing and assembly adjustment are facilitated, and deterioration of optical performance due to errors in processing and assembly adjustment is prevented. Further, even when the image plane is deviated, it is preferable because there is little deterioration in drawing performance. In addition, when the lens surface is aspheric, this aspherical surface is an aspherical surface by grinding, a glass mold aspherical surface made of glass with an aspherical shape, and a composite type in which resin is formed on the glass surface in an aspherical shape. Any aspherical surface 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 in the vicinity of the third lens group G3, but the role of the aperture stop S may be substituted by a lens frame without providing a member as an aperture stop.

  Further, each lens surface may be provided with an antireflection film having a high transmittance in a wide wavelength region in order to reduce flare and ghost and achieve high optical performance with high contrast.

  The zoom optical system ZL according to the present embodiment has a zoom ratio of about 3 to 5.

  In the zoom optical system ZL according to the present embodiment, it is preferable that the first lens group G1 has two positive lens components. In the variable magnification optical system ZL according to this 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 the lens components in the order of negative, positive and negative in order from the object side with an air gap interposed therebetween. Furthermore, in the variable magnification optical system ZL according to this embodiment, it is preferable that the third lens group G3 has two positive lens components. In the zoom optical system ZL according to this embodiment, it is preferable that the fourth lens group G4 has two negative lens components. In the zoom optical system ZL according to the present embodiment, it is preferable that the fifth lens group G5 has one positive lens component. Alternatively, it is preferable that the fifth lens group G5 has two positive lens components.

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

  Hereinafter, an outline of a method for manufacturing the variable magnification optical system ZL according to the present embodiment will be described with reference to FIG. First, each lens is arranged and a lens group is prepared (step S100). Specifically, in this embodiment, for example, in order from the object side, a cemented positive lens CL1 formed by cementing a negative meniscus lens L11 having a convex surface toward the object side and a positive meniscus lens L12 having a convex surface toward the object side; A positive meniscus lens L13 having a convex surface facing the object side is arranged as the first lens group G1, and in order from the object side, an aspheric negative meniscus lens L21 having a convex surface facing the object side and an aspheric surface on the object side surface, A negative meniscus lens L22 having a concave surface on its side, a biconvex lens L23, and an aspherical biconcave lens L23 having an aspheric surface on the image side surface are arranged as a second lens group G2, and the convex surface on the object side is formed in order from the object side. A concave positive meniscus lens L31 and a biconvex lens L32, and a cemented positive lens CL2 and a biconvex lens L33 are arranged to form a third lens group G3. In order from the object side, a fourth lens is formed by arranging a cemented negative lens CL3 formed by cementing a positive meniscus lens L41 having a concave surface facing the object side and a biconcave lens L42, and a negative meniscus lens L43 having a concave surface facing the object side. In order from the object side to the group G4, an aspheric positive lens L51 having a concave surface directed toward the object side and an aspheric surface facing the object side, a positive meniscus lens L52 having a concave surface directed toward the object side, and a concave surface directed toward the object side A cemented positive lens CL4 formed by cementing with the negative meniscus lens L53 is disposed to form a fifth lens group G5. The variable power optical system ZL is manufactured by arranging the lens groups thus prepared.

  At this time, at the time of zooming from the wide-angle end state to the telephoto end state, the fourth lens group G4 and the fifth lens group G5 are arranged so as to move so as to be reduced (step S200). When the focal length of the second lens group G2 is f2, the focal length of the third lens group G3 is f3, and the focal length of the entire system in the wide-angle end state is fw, the above conditional expressions (1) and ( Arrange so as to satisfy 2) (step S300).

  Embodiments of the present application will be described below with reference to the accompanying drawings. FIGS. 1, 3, 5, 7, and 9 show the configurations of the variable magnification optical systems ZL1 to ZL5. As shown in FIGS. 1, 3, 5, 7, and 9, the variable magnification optical systems ZL <b> 1 to ZL <b> 5 according to each example include a first lens group G <b> 1 having a positive refractive power in order from the object side. A second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens having a positive refractive power In the zooming 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 second lens group G2 and the third lens group G3. Each lens group so that the air gap between the third lens group G3 and the fourth lens group G4 increases, and the air gap between the fourth lens group G4 and the fifth lens group G5 decreases. The interval of changes.

  The aperture stop S is located between the second lens group G2 and the third lens group G3, and moves together with the third lens group G3 upon zooming from the wide-angle end state to the telephoto end state. Focusing from infinity to a short-distance object point 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 is joined in order from the object side by a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side. And a positive meniscus lens L13 having a convex surface facing the object side. The second lens group G2, in order from the object side, has an aspheric negative meniscus lens L21 having a convex surface on the object side and an aspheric surface on the object side, a negative meniscus lens L22 having a concave surface on the object side, a biconvex lens L23, and And an aspherical biconcave lens L23 having an aspherical surface on the image side surface. The third lens group G3 includes, in order from the object side, a cemented positive lens CL2 formed by cementing a concave meniscus lens L31 having a convex surface toward the object side and a biconvex lens L32, and a biconvex lens L33.

  The fourth lens group G4 includes, in order from the object side, a cemented negative lens CL3 formed by cementing a positive meniscus lens L41 having a concave surface directed toward the object side and a biconcave lens L42, and a negative meniscus lens L43 having a concave surface directed toward the object side. Consists of The fifth lens group G5 includes, in order from the object side, an aspheric positive lens L51 having a concave surface directed toward the object side and an aspheric surface facing the object side; a positive meniscus lens L52 having a concave surface directed toward the object side; Is composed of a cemented negative lens CL4 formed by cementing with a negative meniscus lens L53 facing the lens.

  In the first example, camera shake correction (anti-vibration) is performed by moving the cemented negative lens CL3 of the fourth lens group G4 in a direction orthogonal to the optical axis.

  Table 1 below lists values of specifications of the first embodiment. In Table 1, f represents the focal length of the entire system, FNO represents the F number, ω represents a half angle of view (unit is “°”), and Bf represents 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 refractive index and Abbe number are each The value for the d-line (λ = 587.6 nm) is shown. Here, “mm” is generally used for the focal length, 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, the same optical performance can be obtained, and the present invention is not limited to this. The radius of curvature of 0.0000 indicates a plane, and the refractive index of air of 1.0000 is omitted. The description of these symbols and the description of the specification table are the same in the following examples.

(Table 1)
Wide angle end Telephoto end
f = 24.70 to 68.00
F.NO = 3.51 to 4.51
ω = 42.63 to 16.87
Image height = 21.6 to 21.6
Total length = 112.599 to 138.896
Bf = 38.818 to 54.481

Surface number Curvature radius Surface spacing Abbe number Refractive index
1 119.6327 2.0000 23.78 1.84666
2 51.5992 5.9473 54.66 1.72915
3 167.6477 0.1000
4 53.0631 4.8163 46.62 1.81600
5 153.0342 (d1)
* 6 170.9361 0.1000 38.09 1.55389
7 106.5297 1.3500 47.38 1.78800
8 12.1629 5.4444
9 -70.1431 1.0000 45.29 1.79499
10 -12967.6190 0.1000
11 44.7347 3.5960 23.78 1.84666
12 -35.0279 0.2750
13 -28.6001 1.2000 40.10 1.85134
* 14 513.7697 (d2)
15 0.0000 0.5000 (Aperture stop S)
16 19.1753 1.5000 31.27 1.90366
17 11.8114 4.5937 67.90 1.59319
18 -46.2164 0.1000
19 36.3395 1.9928 67.90 1.59319
20 -1099.6266 (d3)
21 -34.1938 2.1967 25.45 2.00069
22 -14.4410 1.0000 40.94 1.80610
23 134.8372 2.2858
24 -19.2920 1.0000 45.29 1.79499
25 -29.5578 (d4)
* 26 -255.0409 0.2200 38.09 1.55389
27 -68.0972 4.2876 46.58 1.80400
28 -18.1288 0.3000
29 -366.2097 3.7695 70.41 1.48749
30 -21.6919 1.0000 23.78 1.84666
31 -167.4750 (Bf)

[Lens focal length]
Lens group Start surface Focal length separation First lens group 1 94.37965
Second lens group 6 -17.00020
Third lens group 16 20.63769
4th lens group 21 -27.63787
5th lens group 26 36.61953

  In the first embodiment, the lens surfaces of the sixth surface, the fourteenth surface, and the twenty-sixth surface are formed in an aspherical shape. 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 1.4021OE-05 -5.18660E-08 4.00920E-11 1.50390E-14
14th surface 1.0000 -1.64370E-05 -1.3331OE-08 -1.50790E-09 6.80220E-12
26th surface 1.0000 -5.03290E-05 1.53080E-08 -2.33370E-10 0.00000E + 00

  In the first embodiment, the axial air distance d1 between the first lens group G1 and the second lens group G2, the axial air distance d2 between the second lens group G2 and the third lens group G3, and the third lens group G3. The on-axis air distance d3 between the fourth lens group G4 and the on-axis air distance d4 between the fourth lens group G4 and the fifth lens group G5 changes during zooming. Table 3 below shows variable interval data at each focal length in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system ZL1 according to the first example.

(Table 3)
Wide angle end Intermediate focal length Telephoto end
d1 2.90788 20.86608 26.79652
d2 14.81058 4.73190 1.55737
d3 1.38046 3.50970 4.28626
d4 4.00583 (d4w) 1.87660 1.10000 (d4t)

  Table 4 below shows values corresponding to the conditional expression in the first embodiment. In Table 4, f1 is the focal length of the first lens group G1, f2 is the focal length of the second lens group G2, f3 is the focal length of the third lens group G3, and f4 is the fourth lens group G4. The focal length, fw is the focal length of the entire system in the wide-angle end state, d4w is the air gap between the fourth lens group G4 and the fifth lens group G5 in the wide-angle end state, and d4t is the fourth lens group G4 and the fourth lens group G4. The air space | interval in a telephoto end state with 5 lens groups G5 is each represented. In the following embodiments, the description of the reference numerals is the same unless otherwise specified.

(Table 4)
(1) f3 / (− f2) = 1.21
(2) f1 / fw = 3.82
(3) (d4w-d4t) /fw=0.12
(4) f3 / (− f4) = 0.75
(5) (−f2) /fw=0.69
(6) f2 / f4 = 0.62
(7) f1 / f3 = 4.57

  FIG. 2A shows an aberration diagram in the infinite focus state in the wide-angle end state of this first embodiment, and FIG. 2B shows an aberration diagram in the infinite focus state in the intermediate focal length state. FIG. 2C shows an aberration diagram in the infinite focus state in the end state. In each aberration diagram, a solid line in the astigmatism diagram indicates a sagittal image plane, a broken line indicates a meridional image plane, FNO indicates an F number, Y indicates an image height, and ω indicates a half field angle. In each aberration diagram, d and g represent aberrations at d-line (λ = 587.6 nm) and g-line (λ = 435.6 nm), respectively. As is apparent from these respective aberration diagrams, it is clear that in the first embodiment, various aberrations are corrected well and the imaging performance is excellent.

[Second Embodiment]
FIG. 3 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 of FIG. 3, the first lens group G1 includes, in order from the object side, a cemented positive lens CL1 formed by cementing a negative meniscus lens L11 having a convex surface toward the object side and a biconvex lens L12, and It is composed of a positive meniscus lens L13 having a convex surface facing the object side. The second lens group G2, in order from the object side, has an aspheric negative meniscus lens L21 having a convex surface on the object side and an aspheric surface on the object side, a biconcave lens L22, a biconvex lens L23, and an aspheric surface on the image side. An aspheric negative meniscus lens L24 is used. The third lens group G3 includes, in order from the object side, a cemented negative lens CL2 formed by cementing a concave meniscus lens L31 having a convex surface directed toward the object side and a biconvex lens L32, and a biconvex lens L33.

  The fourth lens group G4 includes, in order from the object side, a cemented negative lens CL3 formed by cementing a positive meniscus lens L41 having a concave surface directed toward the object side and a biconcave lens L42, and a negative meniscus lens L43 having a concave surface directed toward the object side. Consists of The fifth lens group G5 includes, in order from the object side, an aspheric positive lens L51 having a concave surface directed to the object side and an aspheric surface on the object side, a biconvex lens L52, and a negative meniscus lens L53 having a concave surface directed to the object side. This is composed of a cemented negative lens CL4.

  In the second example, camera shake correction (anti-vibration) is performed by moving the cemented negative lens CL3 of the fourth lens group G4 in a direction orthogonal to the optical axis.

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

(Table 5)
Wide angle end Telephoto end
f = 24.70 to 82.50
F.NO = 3.60 to 4.60
ω = 42.62 to 14.04
Image height = 21.6 to 21.6
Total length = 121.098 to 158.098
Bf = 38.818 to 58.586

Surface number Curvature radius Surface spacing Abbe number Refractive index
1 493.7028 2.0000 23.78 1.84666
2 91.8270 6.5000 54.66 1.72916
3 -397.4511 0.1000
4 50.0642 4.2615 49.61 1.77250
5 92.7163 (d1)
* 6 58.1931 0.1400 38.09 1.55389
7 73.0305 1.3500 42.72 1.83481
8 12.5058 5.9710
9 -50.7335 1.0000 49.61 1.77250
10 119.0154 0.1000
11 67.9846 3.8696 23.78 1.84666
12 -28.6111 0.1537
13 -26.7639 1.0000 40.94 1.80610
* 14 -150.1370 (d2)
15 0.0000 0.5000 (Aperture stop S)
16 21.9480 1.4780 31.27 1.90366
17 14.3469 5.1437 82.56 1.49782
18 -38.0929 0.1000
19 26.7398 2.7410 70.45 1.48749
20 -362.8585 (d3)
21 -42.7051 2.6106 32.35 1.85026
22 -15.2281 1.0000 50.24 1.71999
23 109.5535 2.2966
24 -22.3871 1.0000 55.52 1.69680
25 -46.4739 (d4)
* 26 -303.9316 0.2000 38.09 1.55389
27 -80.8569 4.4886 46.58 1.80400
28 -20.1230 0.7000
29 162.2628 5.1828 70.45 1.48749
30 -25.6127 1.0000 23.78 1.84666
31 -843.7978 (Bf)

[Lens focal length]
Lens group Start surface Focal length separation 1st lens group 1 103.18796
Second lens group 6 -17.51593
Third lens group 16 22.89002
Fourth lens group 21 -28.72503
5th lens group 26 36.52696

  In the second embodiment, the lens surfaces of the sixth surface, the fourteenth 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 -4.22970E-06 -3.33950E-08 -7.99730E-11 2.41860E-13
14th surface 1.0000 -1.85220E-05 -7.78240E-08 -2.01280E-10 -1.35490E-12
26th surface 1.0000 -3.45120E-05 -6.00890E-09 -6.40440E-11 0.OOOOOE + 00

  In the second embodiment, the axial air distance d1 between the first lens group G1 and the second lens group G2, the axial air distance d2 between the second lens group G2 and the third lens group G3, and the third lens group G3. The on-axis air distance d3 between the fourth lens group G4 and the on-axis air distance d4 between the fourth lens group G4 and the fifth lens group G5 changes during zooming. Table 7 below shows variable interval data at each focal length in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system ZL2 according to the second example.

(Table 7)
Wide angle end Intermediate focal length Telephoto end
d1 2.98229 20.32592 35.45766
d2 16.29014 6.35565 1.05000
d3 2.75730 5.42675 6.96720
d4 5.36317 (d4w) 2.69552 1.15000 (d4t)

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

(Table 8)
(1) f3 / (− f2) = 1.31
(2) f1 / fw = 4.18
(3) (d4w-d4t) /fw=0.17
(4) f3 / (− f4) = 0.80
(5) (−f2) /fw=0.71
(6) f2 / f4 = 0.61
(7) f1 / f3 = 4.51

  FIG. 4A shows an aberration diagram in the infinite focus state in the wide-angle end state of this second embodiment, and FIG. 4B shows an aberration diagram in the infinite focus state in the intermediate focal length state. FIG. 4C shows an aberration diagram in the infinite focus state in the end state. As is apparent from these respective aberration diagrams, it is clear that in the second embodiment, various aberrations are corrected satisfactorily and the imaging performance is excellent.

[Third embodiment]
FIG. 5 is a diagram showing a configuration of the variable magnification optical system ZL3 according to the third example. In the variable magnification optical system ZL3 of FIG. 5, the first lens group G1 includes, in order from the object side, a cemented positive lens CL1 formed by cementing a negative meniscus lens L11 having a convex surface facing the object side and a biconvex lens L12, and It is composed of a positive meniscus lens L13 having a convex surface facing the object side. The second lens group G2, in order from the object side, has an aspheric negative meniscus lens L21 having a convex surface on the object side and an aspheric surface on the object side, a negative meniscus lens L22 having a concave surface on the object side, a biconvex lens L23, and And an aspherical biconcave lens L24 having an aspherical surface on the image side surface. The third lens group G3 includes, in order from the object side, a cemented positive lens CL2 composed of a negative meniscus lens L31 having a convex surface facing the object side and a biconvex lens L32, and a positive meniscus lens L33 having a convex surface facing the object side. Consists of

  The fourth lens group G4 includes, in order from the object side, a cemented negative lens CL3 formed by cementing a positive meniscus lens L41 having a concave surface directed toward the object side and a biconcave lens L42, and a negative meniscus lens L43 having a concave surface directed toward the object side. Consists of The fifth lens group G5 includes, in order from the object side, an aspheric positive lens L51 having a concave surface directed toward the object side and an aspheric surface facing the object side; a positive meniscus lens L52 having a concave surface directed toward the object side; Is composed of a cemented negative lens CL4 formed by cementing with a negative meniscus lens L53 facing the lens.

  In the third example, camera shake correction (anti-vibration) is performed by moving the cemented negative lens CL3 of the fourth lens group G4 in a direction orthogonal to the optical axis.

  Table 9 below shows values of specifications of the third embodiment.

(Table 9)
Wide angle end Telephoto end
f = 28.80 to 102.00
F.NO = 3.63 to 4.62
ω = 38.28 to 9.85
Image height = 21.6 to 21.6
Total length = 123.531 to 157.844
Bf = 38.818 to 54.339

Surface number Curvature radius Surface spacing Abbe number Refractive index
1 373.4938 2.0000 23.78 1.84666
2 77.6757 6.7304 49.61 1.77250
3 -1234.3385 0.1000
4 48.2194 4.5930 52.29 1.75500
5 101.7218 (d1)
* 6 47.1145 0.1593 38.09 1.55389
7 50.8335 1.3500 42.72 1.83481
8 12.6630 5.5655
9 -52.3028 1.0000 46.63 1.81600
10 227.2789 0.1000
11 32.8197 3.9598 23.78 1.84666
12 -42.6430 0.3193
13 -31.8833 1.2000 42.72 1.83481
* 14 116.8095 (d2)
15 0.0000 0.5000 (Aperture stop S)
16 23.2900 1.0000 29.37 1.95000
17 15.2398 5.0245 82.56 1.49782
18 -27.9655 0.1000
19 31.1370 2.3000 65.47 1.60300
20 553.0656 (d3)
21 -69.4703 2.0528 32.35 1.85026
22 -21.5187 1.0000 54.66 1.72916
23 128.1185 3.0000
24 -23.0906 1.0000 49.61 1.77250
25 -65.5308 (d4)
* 26 -77.3371 0.2200 38.09 1.55389
27 -92.4298 5.0000 46.58 1.80400
28 -18.4338 2.0000
29 -142.5947 4.5000 70.41 1.48749
30 -27.4884 1.0000 23.78 1.84666
31 -189.9631 (Bf)

[Lens focal length]
Lens group Start surface Focal length separation 1st lens group 1
Second lens group 6 -17.43082
Third lens group 16 21.90000
4th lens group 21 -28.69220
5th lens group 26 41.26939

  In the third embodiment, the lens surfaces of the sixth surface, the fourteenth 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 -4.40512E-06 -3.71332E-08 1.47511E-11 1.31683E-14
14th surface 1.0000 -1.32774E-05 -5.36912E-08 -1.55477E-10 9.34102E-13
26th surface 1.0000 -4.17159E-05 -2.45154E-09 -2.01155E-10 0.OOOOOE + 00

  In the third example, the axial air gap d1 between the first lens group G1 and the second lens group G2, the axial air gap d2 between the second lens group G2 and the third lens group G3, and the third lens group G3. The on-axis air distance d3 between the fourth lens group G4 and the on-axis air distance d4 between the fourth lens group G4 and the fifth lens group G5 changes during zooming. Table 11 below shows variable interval data at each focal length in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system ZL3 according to the third example.

(Table 11)
Wide angle end Intermediate focal length Telephoto end
d1 3.18675 17.24856 37.12206
d2 16.64276 8.80625 1.50000
d3 3.47378 6.09325 8.00899
d4 5.63522 (d4w) 3.01569 1.10000 (d4t)

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

(Table 12)
(1) f3 / (− f2) = 1.26
(2) f1 / fw = 3.42
(3) (d4w-d4t) /fw=0.16
(4) f3 / (− f4) = 0.76
(5) (−f2) /fw=0.62
(6) f2 / f4 = 0.61
(7) f1 / f3 = 4.37

  FIG. 6A shows an aberration diagram in the infinite focus state in the wide-angle end state of this third embodiment, and FIG. 6B shows an aberration diagram in the infinite focus state in the intermediate focal length state. FIG. 6C shows an aberration diagram in the infinite focus state in the end state. As is apparent from these respective aberration diagrams, it is clear that in the third example, the various aberrations are corrected well and the imaging performance is excellent.

[Fourth embodiment]
FIG. 7 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. 7, the first lens group G1 is joined in order from the object side by a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side. And a positive meniscus lens L13 having a convex surface facing the object side. The second lens group G2, in order from the object side, has an aspheric negative meniscus lens L21 having a convex surface on the object side and an aspheric surface on the object side, a negative meniscus lens L22 having a concave surface on the object side, and a biconvex lens L23. And a cemented positive lens CL2 formed by cementing with an aspheric negative meniscus lens L24 having an aspheric surface on the image side and an aspheric surface on the object side. The third lens group G3 includes, in order from the object side, a cemented positive lens CL3 formed by cementing a negative meniscus lens L31 having a convex surface toward the object side and a biconvex lens L32, and a biconvex lens L33.

  The fourth lens group G4 includes, in order from the object side, a cemented negative lens CL4 formed by cementing a positive meniscus lens L41 having a concave surface directed toward the object side and a biconcave lens L42, and a negative meniscus lens L43 having a concave surface directed toward the object side. Consists of The fifth lens group G5 includes, in order from the object side, an aspheric positive lens L51 having an aspheric surface on the object side, a positive meniscus lens L52 with a concave surface facing the object side, and a negative meniscus lens L53 with a concave surface facing the object side. This is composed of a cemented negative lens CL5.

  In the fourth example, camera shake correction (anti-vibration) is performed by moving the cemented negative lens CL4 of the fourth lens group G4 in a direction orthogonal to the optical axis.

  Table 13 below lists values of specifications of the fourth embodiment.

(Table 13)
Wide angle end Telephoto end
f = 24.70 to 87.20
F.NO = 3.60 to 5.80
ω = 42.64 to 11.49
Image height = 21.6 to 21.6
Total length = 124.699 〜 156.696
Bf = 38.819 to 56.191

Surface number Curvature radius Surface spacing Abbe number Refractive index
1 372.6274 2.0000 23.78 1.84666
2 75.9854 6.7706 49.61 1.77249
3 14844.1810 0.1000
4 50.9400 4.9948 46.62 1.81600
5 114.4889 (d1)
* 6 73.7591 0.1000 41.42 1.53610
7 70.2551 1.3500 42.72 1.83480
8 12.9582 7.0662
9 -45.1259 1.0000 42.72 1.83480
10 -115.7746 0.1000
11 130.5670 3.9850 22.79 1.80809
12 -25.0000 1.2000 42.71 1.82079
* 13 -5015.0001 (d2)
14 0.0000 0.5000 (Aperture stop S)
15 24.3980 1.3049 31.27 1.90366
16 13.4702 4.2437 65.46 1.60300
17 -57.0278 0.1000
18 29.6013 2.6177 82.52 1.49782
19 -71.1125 (d3)
20 -37.4166 2.4500 25.45 2.00069
21 -15.0220 1.0000 40.94 1.80610
22 151.7344 4.1314
23 -33.7925 1.0000 46.58 1.80400
24 -87.2793 (d4)
* 25 388.1656 0.2200 41.42 1.53610
26 -145.3355 4.6004 40.94 1.80610
27 -20.4944 0.3000
28 -224.8928 4.3669 70.41 1.48749
29 -21.8074 1.0000 23.78 1.84666
30 -900.0000 (Bf)

[Lens focal length]
Lens group Start surface Focal length separation first lens group 1 96.08538
Second lens group 6 -16.89627
Third lens group 15 21.34372
Fourth lens group 20 -28.60078
5th lens group 25 43.38019

  In the fourth embodiment, the sixth, thirteenth and twenty-fifth lens surfaces are aspherical. 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 3.30880E-08 -3.84340E-08 7.47270E-11 -1.03500E-13
13th surface 1.0000 -1.43270E-05 -9.77370E-08 4.07760E-10 -3.09250E-12
25th surface 1.0000 -3.96100E-05 4.06470E-09 -9.63610E-11 0.00000E + 00

  In the fourth embodiment, the axial air distance d1 between the first lens group G1 and the second lens group G2, the axial air distance d2 between the second lens group G2 and the third lens group G3, and the third lens group G3. The on-axis air distance d3 between the fourth lens group G4 and the on-axis air distance d4 between the fourth lens group G4 and the fifth lens group G5 changes during zooming. Table 15 below shows variable interval data at each focal length in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system ZL5 according to the fourth example.

(Table 15)
Wide angle end Intermediate focal length Telephoto end
d1 3.10000 19.45499 34.60972
d2 18.37739 7.76715 1.50000
d3 1.99464 4.84201 6.59326
d4 5.90657 (d4w) 3.05904 1.30000 (d4t)

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

(Table 16)
(1) f3 / (− f2) = 1.26
(2) f1 / fw = 3.89
(3) (d4w-d4t) /fw=0.19
(4) f3 / (− f4) = 0.75
(5) (−f2) /fw=0.68
(6) f2 / f4 = 0.59
(7) f1 / f3 = 4.50

  FIG. 8A shows an aberration diagram in the infinite focus state in the wide-angle end state of this fourth embodiment, and FIG. 8B shows an aberration diagram in the infinite focus state in the intermediate focal length state. FIG. 8C shows an aberration diagram in the infinite focus state in the end state. As is apparent from these respective aberration diagrams, it is clear that in the fourth example, various aberrations are satisfactorily corrected and the imaging performance is excellent.

[Fifth embodiment]
FIG. 9 is a diagram showing a configuration of the variable magnification optical system ZL5 according to the fifth example. In the variable magnification optical system ZL5 of FIG. 9, the first lens group G1 is joined in order from the object side by a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side. And a positive meniscus lens L13 having a convex surface facing the object side. The second lens group G2, in order from the object side, has an aspheric negative meniscus lens L21 having a convex surface on the object side and an aspheric surface on the object side, a negative meniscus lens L22 having a concave surface on the object side, and a biconvex lens L23. And a cemented positive lens CL2 formed by cementing with an aspheric negative meniscus lens L24 having an aspheric surface on the image side and an aspheric surface on the object side. The third lens group G3 includes, in order from the object side, a cemented positive lens CL3 formed by cementing a negative meniscus lens L31 having a convex surface toward the object side and a biconvex lens L32, and a biconvex lens L33.

  The fourth lens group G4 includes, in order from the object side, a cemented negative lens CL4 formed by cementing a positive meniscus lens L41 having a concave surface directed toward the object side and a biconcave lens L42, and a negative meniscus lens L43 having a concave surface directed toward the object side. Consists of The fifth lens group G5 includes, in order from the object side, an aspheric positive lens L51 having an aspheric surface on the object side, a positive meniscus lens L52 with a concave surface facing the object side, and a negative meniscus lens L53 with a concave surface facing the object side. This is composed of a cemented negative lens CL5.

  In the fifth embodiment, camera shake correction (anti-vibration) is performed by moving the cemented negative lens CL4 of the fourth lens group G4 in a direction orthogonal to the optical axis.

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

(Table 17)
Wide angle end Telephoto end
f = 22.55 to 77.20
F.NO = 3.59 to 5.78
ω = 45.22 to 15.08
Image height = 21.6 to 21.6
Total length = 126.365 to 166.395
Bf = 38.819 to 68.503

Surface number Curvature radius Surface spacing Abbe number Refractive index
1 3000.0000 2.0000 23.78 1.84666
2 100.5704 5.0710 49.61 1.77249
3 1103.1027 0.1000
4 61.3430 4.9688 46.62 1.81600
5 199.6806 (d1)
* 6 57.3089 0.1000 41.42 1.53610
7 54.9009 1.3500 42.72 1.83481
8 12.9643 7.7463
9 -42.1100 1.0000 42.72 1.83481
10 -157.1970 0.1000
11 100.6959 4.2633 22.79 1.80809
12 -26.6968 1.2000 42.71 1.82079
* 13 -739.7322 (d2)
14 0.0000 0.5000 (Aperture stop S)
15 25.1876 1.5000 31.27 1.90366
16 13.9732 4.9264 65.46 1.60 300
17 -74.5596 0.1000
18 28.3447 2.9402 82.52 1.49782
19 -73.1263 (d3)
20 -36.2470 2.4500 25.45 2.00069
21 -15.0096 1.0000 40.94 1.80610
22 312.0276 3.6428
23 -45.6498 1.0000 42.72 1.83481
24 -771.8920 (d4)
* 25 203.2702 0.2200 41.42 1.53610
26 -255.2250 4.6508 40.94 1.80610
27 -21.8434 0.3000
28 -2672.0362 4.3134 70.41 1.48749
29 -22.7690 1.0000 23.78 1.84666
30 -900.0000 (Bf)

[Lens focal length]
Lens group Start surface Focal length separation 1st lens group 1 121.86217
Second lens group 6 -17.82540
Third lens group 15 22.49990
Fourth lens group 20 -27.88943
5th lens group 25 39.72862

  In the fifth embodiment, the sixth, thirteenth, and twenty-fifth lens surfaces are aspherical. 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 8.62870E-06 -3.15620E-08 -3.40720E-12 -1.85500E-14
13th surface 1.0000 -9.91640E-06 -5.81720E-08 -1.71080E-12 -1.15620E-12
25th surface 1.0000 -3.49860E-05 8.58470E-09 -1.10080E-10 0.00000E + 00

  In the fifth embodiment, the axial air gap d1 between the first lens group G1 and the second lens group G2, the axial air gap d2 between the second lens group G2 and the third lens group G3, and the third lens group G3. The on-axis air distance d3 between the fourth lens group G4 and the on-axis air distance d4 between the fourth lens group G4 and the fifth lens group G5 changes during zooming. Table 19 below shows variable interval data at each focal length in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system ZL5 according to the fifth example.

(Table 19)
Wide angle end Intermediate focal length Telephoto end
d1 2.76993 20.20213 31.60535
d2 19.97523 6.47914 1.50000
d3 2.28121 5.46623 7.04383
d4 6.07697 (d4w) 2.89189 1.30000 (d4t)

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

(Table 20)
(1) f3 / (− f2) = 1.26
(2) f1 / fw = 5.42
(3) (d4w-d4t) /fw=0.21
(4) f3 / (− f4) = 0.81
(5) (−f2) /fw=0.79
(6) f2 / f4 = 0.64
(7) f1 / f3 = 5.42

  FIG. 10A shows an aberration diagram in the infinite focus state in the wide-angle end state of this fifth embodiment, and FIG. 10B shows an aberration diagram in the infinite focus state in the intermediate focal length state. FIG. 10C shows an aberration diagram in the infinite focus state in the end state. As is apparent from these respective aberration diagrams, it is clear that in the fifth example, various aberrations are corrected well and the imaging performance is excellent.

ZL (ZL1 to ZL5) Variable magnification optical system G1 First lens group G2 Second lens group G3 Third lens group G4 Fourth lens group G5 Fifth lens group 1 Digital single-lens reflex camera (optical apparatus)

Claims (14)

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;
A fourth lens group having negative refractive power;
A fifth lens group having a positive refractive power,
Upon zooming from the wide-angle end state to the telephoto end state, the distance between the fourth lens group and the fifth lens group is reduced and moved.
When the focal length of the first lens group is f1, the focal length of the second lens group is f2, the focal length of the third lens group is f3, and the focal length of the entire system in the wide-angle end state is fw. The following formula 0.10 <f3 / (− f2) <1.35
3.0 <f1 / fw <20.0
Variable magnification optical system that satisfies the above conditions. At the time of zooming from the wide-angle end state to the telephoto end state, the air gap between the fourth lens group and the fifth lens group in the wide-angle end state is d4w, and the fourth lens group and the fifth lens group When the air interval in the telephoto end state is d4t, the following formula (d4w−d4t) / fw> 0.00
The zoom optical system according to claim 1, wherein the following condition is satisfied. When the focal length of the fourth lens group is f4, the following formula 0.50 <f3 / (− f4) <1.50
The zoom optical system according to claim 1, wherein the zoom lens satisfies the following condition. The following formula 0.58 <(− f2) / fw <0.95
The variable magnification optical system as described in any one of Claims 1-3 which satisfy | fills these conditions. When the focal length of the fourth lens group is f4, the following formula 0.40 <f2 / f4 <1.20
The zoom lens system according to any one of claims 1 to 4, which satisfies the following condition. The following expression 3.0 <f1 / f3 <10.0
The zoom lens system according to any one of claims 1 to 5, which satisfies the following condition.   The zoom optical system according to claim 1, wherein at least a part of the second lens group moves on the optical axis when focusing from infinity to a short-distance object point.   The zoom lens system according to any one of claims 1 to 7, wherein a lens surface closest to the image side of the second lens group has an aspherical shape.   The variable power optical system according to any one of claims 1 to 8, wherein the fourth lens group includes at least one cemented lens. When zooming from the wide-angle end state to the telephoto end state,
An interval between the first lens group and the second lens group is increased;
An interval between the second lens group and the third lens group is reduced;
An interval between the third lens group and the fourth lens group is increased;
The variable magnification optical system according to any one of claims 1 to 9, wherein each lens group moves so that an interval between the fourth lens group and the fifth lens group decreases.   11. The variable magnification optical system according to claim 1, wherein at least a part of the fourth lens group moves so as to have a component in a direction orthogonal to the optical axis.   The zoom lens system according to any one of claims 1 to 11, wherein a lens surface closest to the object side of the second lens group has an aspherical shape.   An optical apparatus comprising the photographing lens according to claim 1. In order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens having a negative refractive power A variable magnification optical system having a group and a fifth lens group having a positive refractive power,
When zooming from the wide-angle end state to the telephoto end state, the distance between the fourth lens group and the fifth lens group is reduced and moved.
When the focal length of the first lens group is f1, the focal length of the second lens group is f2, the focal length of the third lens group is f3, and the focal length of the entire system in the wide-angle end state is fw. The following formula 0.10 <f3 / (− f2) <1.35
3.0 <f1 / fw <20.0
A method for manufacturing a variable magnification optical system arranged so as to satisfy the above condition.

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