JP2015026027A - Variable power optical system, optical device, and method for manufacturing variable power optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable power optical system in which the variation in size of an image during focus adjustment is suppressed, and the variation in aberrations during power variation and during focusing is excellently suppressed, and to provide an optical device and a method for manufacturing the variable power optical system.SOLUTION: A variable power optical system ZL to be used in an optical device such as a camera 1, 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; a third lens group having a negative refractive power; a fourth lens group having a positive refractive power; and a fifth lens group having a positive refractive power. When varying power from a wide angle end state to a telephoto end state, the distances between the lens groups are changed. When focusing from an infinite object to a short distance object, the third lens group moves in the optical axis direction.

Description

  The present invention relates to a variable magnification optical system, an optical apparatus, 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). In recent electronic still cameras and video cameras, so-called contrast AF is generally used in which a focusing lens group is moved and a signal from an image sensor is used to focus on the contrast of an image.

JP 2007-093975 A

  However, the conventional variable magnification optical system has a problem that the size of the image changes greatly during focusing with contrast AF, and it feels unnatural.

  The present invention has been made in view of such problems, and it is possible to suppress a change in the size of an image during focusing, and to further reduce a change in aberrations during zooming and focusing. It is an object of the present invention to provide an optical system, an optical device, and a method for manufacturing a variable magnification optical system.

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 negative refraction. A third lens group having a power, a fourth lens group having a positive 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 first lens group and the second lens group changes, the distance between the second lens group and the third lens group changes, the distance between the third lens group and the fourth lens group changes, and the fourth The distance between the lens group and the fifth lens group changes, and the third lens group moves in the optical axis direction when focusing from an object at infinity to an object at a short distance, and satisfies the following condition: To do.
1.10 <f1 / (− f2) <2.00
However,
f1: Focal length of the first lens group f2: Focal length of the second lens group

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

  Further, in such a variable magnification optical system, the distance between the first lens group and the second lens group is increased during the magnification change from the wide-angle end state to the telephoto end state, and the third lens group and the fourth lens group It is preferable that the interval is reduced.

Moreover, it is preferable that such a variable magnification optical system satisfies the condition of the following formula.
0.990 <(A × B) / (C × D) <1.013
However,
A = f3 × (1−β3w) ² × (1 + β3w) × βbw ² −Δ × β3w ²
B = fbw × (1−βbw) + Δ
C = f3 × (1−β3w) ² × (1 + β3w) × βbw ² −Δ × β3w
D = fbw × (1−βbw) + Δ / βbw
Δ = Ymax / 50
β3w: Imaging magnification of the third lens group in the wide-angle end state βbw: Composite imaging magnification of the fourth lens group and subsequent lenses in the wide-angle end state Ymax: Maximum image height f3: Focal length of the third lens group fbw: Wide angle Combined focal length of the fourth lens unit and subsequent lenses in the end state

  In addition, in such a variable power optical system, the fourth lens group and the fifth lens group move in the object direction during zooming from the wide-angle end state to the telephoto end state, and the second lens group and the third lens group. It is preferable that the distance between the fourth lens group and the fifth lens group decreases.

Moreover, it is preferable that such a variable magnification optical system satisfies the condition of the following formula.
0.35 <f3 / f2 <0.90
However,
f3: focal length of the third lens unit

Moreover, it is preferable that such a variable magnification optical system satisfies the condition of the following formula.
3.50 <f1 / fw <5.50
However,
fw: focal length of the entire variable magnification optical system in the wide-angle end state

Moreover, it is preferable that such a variable magnification optical system satisfies the condition of the following formula.
0.72 <f4 / f5 <1.45
However,
f4: focal length of the fourth lens group f5: focal length of the fifth lens group

Moreover, it is preferable that such a variable magnification optical system satisfies the condition of the following formula.
0.15 <(D45w−D45t) / fw <0.40
However,
D45w: the distance between the fourth lens group and the fifth lens group in the wide-angle end state D45t: the distance between the fourth lens group and the fifth lens group in the telephoto end state fw: the entire system of the variable power optical system in the wide-angle end state Focal length

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

The variable magnification optical system manufacturing method according to the present invention has, 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 negative refractive power. A method of manufacturing a variable magnification optical system having a third lens group, a fourth lens group having a positive refractive power, and a fifth lens group having a positive refractive power, from a wide-angle end state to a telephoto end state During zooming, the distance between the first lens group and the second lens group changes, the distance between the second lens group and the third lens group changes, and the distance between the third lens group and the fourth lens group. Is arranged so that the distance between the fourth lens group and the fifth lens group changes, and the third lens group moves in the optical axis direction when focusing from an infinite object to a short-distance object. It arrange | positions and it arrange | positions so that the conditions of following Formula may be satisfied.
1.10 <f1 / (− f2) <2.00
However,
f1: Focal length of the first lens group f2: Focal length of the second lens group

  According to the present invention, there is provided a variable power optical system, an optical device, and a variable power optical system that suppress a change in image size during focusing, and further suppress aberration fluctuations during zooming and focusing. A manufacturing method can be provided.

It is sectional drawing which shows the lens structure of the variable magnification optical system which concerns on a 1st Example. FIG. 4 is a diagram illustrating various aberrations of the variable magnification optical system according to the first example when focusing on infinity, where (a) shows a wide-angle end state, (b) shows an intermediate focal length state, and (c) shows telephoto. Indicates the end state. FIG. 6 is a diagram illustrating various aberrations of the variable magnification optical system according to the first example when focusing at short distance, where (a) shows a wide-angle end state, (b) shows an intermediate focal length state, and (c) shows telephoto. Indicates the end state. It is sectional drawing which shows the lens structure of the variable magnification optical system which concerns on a 2nd Example. FIG. 6 is a diagram showing various aberrations of the variable magnification optical system according to Example 2 when focusing at infinity, (a) showing a wide-angle end state, (b) showing an intermediate focal length state, and (c) showing telephoto. Indicates the end state. FIG. 6 is a diagram illustrating various aberrations of the variable magnification optical system according to Example 2 when focusing at short distance, (a) showing a wide-angle end state, (b) showing an intermediate focal length state, and (c) showing telephoto. Indicates the end state. It is sectional drawing which shows the lens structure of the variable magnification optical system which concerns on a 3rd Example. FIG. 10 is a diagram illustrating various aberrations of the variable magnification optical system according to Example 3 at the time of focusing on infinity, where (a) shows a wide-angle end state, (b) shows an intermediate focal length state, and (c) shows telephoto. Indicates the end state. FIG. 6 is a diagram illustrating various aberrations of the zoom optical system according to the third example when focusing at short distance, where (a) illustrates a wide-angle end state, (b) illustrates an intermediate focal length state, and (c) illustrates telephoto. Indicates the end state. A sectional view of a camera carrying the above-mentioned variable magnification optical system is shown. It is a flowchart for demonstrating the manufacturing method of the said variable magnification optical system.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the variable magnification optical system ZL according to the present embodiment 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, The lens unit includes a third lens group G3 having negative refractive power, a fourth lens group G4 having positive refractive power, and a fifth lens group G5 having positive refractive power. In addition, in the zoom optical system ZL, when the zoom is changed 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 is increased, and the second lens group G2 and the third lens are increased. The distance between the group G3 is changed, the distance between the third lens group G3 and the fourth lens group G4 is decreased, and the distance between the fourth lens group G4 and the fifth lens group G5 is changed to improve the zooming ratio. Aberration correction can be achieved.

  Such a zoom optical system ZL increases the distance between the first lens group G1 and the second lens group G2 during zooming from the wide-angle end state to the telephoto end state, and the third lens group G3 and the fourth lens. By reducing the distance from the group G4, a zoom ratio of about 5 times or more can be secured. Further, the first lens group G1 is moved in the object direction at the time of zooming from the wide-angle end state to the telephoto end state, so that the total lens length in the wide-angle end state is shortened and the first lens group G1 is effective. The diameter can be reduced, and the variable magnification optical system ZL can be reduced in size.

  Further, such a variable magnification optical system ZL is configured to move the third lens group G3 in the optical axis direction when focusing from an object at infinity to an object at a short distance, so that an image at the time of focusing can be obtained. Changes in size can be suppressed.

  In addition, it is desirable that such a variable magnification optical system ZL satisfies the following conditional expression (1).

1.10 <f1 / (− f2) <2.00 (1)
However,
f1: Focal length of the first lens group G1 f2: Focal length of the second lens group G2

  Conditional expression (1) defines an appropriate ratio between the focal length of the first lens group G1 and the focal length of the second lens group G2. The variable magnification optical system ZL according to the present embodiment satisfies the conditional expression (1), thereby reducing the total lens length and the effective diameter of the first lens group G1, as well as distortion aberration, field curvature, spherical aberration, and the like. Good correction of various aberrations can be performed. If the lower limit value of conditional expression (1) is not reached, the refractive power of the first lens group G1 becomes large, and it becomes difficult to satisfactorily correct various aberrations including spherical aberration. In addition, the effect of this application can be made more reliable by setting the lower limit of conditional expression (1) to 1.20. On the other hand, if the upper limit value of the conditional expression (1) is exceeded, the refractive power of the first lens group G1 becomes small, and it becomes difficult to reduce the total lens length and the effective diameter of the first lens group G1. In addition, the effect of this application can be made more reliable by setting the upper limit of conditional expression (1) to 1.90.

  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 fourth lens group G4 and the fifth lens group G5 move in the object direction, and the second lens group G2 It is desirable that the distance between the third lens group G3 increases and the distance between the fourth lens group G4 and the fifth lens group G5 decreases. With this configuration, it is possible to more reliably ensure aberration correction at the time of zooming from the wide-angle end state to the telephoto end state and a zoom ratio of about 5 times or more.

  In addition, it is desirable that such a variable magnification optical system ZL satisfies the following conditional expression (2).

0.990 <(A × B) / (C × D) <1.013 (2)
However,
A = f3 × (1−β3w) ² × (1 + β3w) × βbw ² −Δ × β3w ²
B = fbw × (1−βbw) + Δ
C = f3 × (1−β3w) ² × (1 + β3w) × βbw ² −Δ × β3w
D = fbw × (1−βbw) + Δ / βbw
Δ = Ymax / 50
β3w: Imaging magnification of the third lens group G3 in the wide-angle end state βbw: Composite imaging magnification of the lens group after the fourth lens group G4 in the wide-angle end state Ymax: Maximum image height f3: Focal length of the third lens group G3 fbw: the combined focal length of the lens groups after the fourth lens group G4 in the wide-angle end state

  Conditional expression (2) defines the change at the wide-angle end of the image size when the third lens group G3 is moved in the optical axis direction for focusing (focusing). More specifically, it defines the ratio of the change in focal length when defocusing is applied in an amount of 1/50 of the maximum image height in the wide-angle end state. By satisfying conditional expression (2), the zoom optical system ZL according to the present embodiment can suppress the change in the image size at the time of focusing at an inconspicuous level. Regardless of which the upper limit value or lower limit value of the conditional expression (2) is exceeded, the change in the size of the image at the time of focusing increases, making it more noticeable. In addition, the effect of this application can be made more reliable by setting the lower limit of conditional expression (2) to 0.995. Or the effect of this application can be made more reliable by setting the upper limit of conditional expression (2) to 1.010.

  With the above configuration, it is possible to realize a variable magnification optical system ZL that suppresses a change in the size of an image during focusing (focusing).

  Moreover, it is desirable that such a variable magnification optical system ZL satisfies the following conditional expression (3).

0.35 <f3 / f2 <0.90 (3)
However,
f2: Focal length of the second lens group G2 f3: Focal length of the third lens group G3

  Conditional expression (3) defines an appropriate focal length of the third lens group G3 with respect to the focal length of the second lens group G2. The zoom optical system ZL according to the present embodiment can satisfy the conditional expression (3), thereby suppressing a change in the size of the image during focusing and satisfactorily correcting an aberration change during focusing. it can. If the lower limit value of conditional expression (3) is not reached, the refractive power of the third lens group G3 increases, and the change in the image size during focusing increases. In addition, the effect of this application can be made more reliable by setting the lower limit of conditional expression (3) to 0.41. On the other hand, if the upper limit value of the conditional expression (3) is exceeded, the refractive power of the third lens group G3 decreases, and the amount of movement of the third lens group G3 at the time of focusing increases. Changes in various aberrations including field curvature increase. In addition, the effect of this application can be made more reliable by setting the upper limit of conditional expression (3) to 0.63.

  In addition, it is desirable that such a variable magnification optical system ZL satisfies the following conditional expression (4).

3.50 <f1 / fw <5.50 (4)
However,
fw: focal length of the entire zooming optical system ZL in the wide-angle end state f1: focal length of the first lens group G1

  Conditional expression (4) defines the focal length of the first lens group G1 with respect to the focal length of the variable magnification optical system ZL in the wide-angle end state. The variable magnification optical system ZL according to the present embodiment satisfies the conditional expression (4), thereby reducing the total lens length and the effective diameter of the first lens group G1, as well as distortion aberration, field curvature, spherical aberration, and the like. Good correction of various aberrations can be performed. If the lower limit of conditional expression (4) is not reached, the refractive power of the first lens group G1 will increase, and it will be difficult to satisfactorily correct various aberrations such as distortion, curvature of field, and spherical aberration. In addition, the effect of this application can be made more reliable by setting the lower limit of conditional expression (4) to 3.80. On the other hand, if the upper limit value of the conditional expression (4) is exceeded, the refractive power of the first lens group G1 becomes small, and it becomes difficult to reduce the total lens length and the effective diameter of the first lens group G1. In addition, the effect of this application can be made more reliable by setting the upper limit of conditional expression (4) to 5.10.

  By the way, in the variable magnification optical system ZL according to the present embodiment, the fourth lens group G4 and the fifth lens group G5 have a structure that is substantially afocal in the wide-angle end state. The zoom lens has a structure that satisfactorily corrects various aberrations from the wide-angle end state to the telephoto end state by changing it so as to decrease upon zooming from the wide-angle end state to the telephoto end state. It is desirable that the focal length of each lens group of the fourth lens group G4 and the fifth lens group G5 and the air gap between the fourth lens group G4 and the fifth lens group G5 satisfy the following conditions.

  First, it is desirable that such a variable magnification optical system ZL satisfies the following conditional expression (5).

0.72 <f4 / f5 <1.45 (5)
However,
f4: focal length of the fourth lens group G4 f5: focal length of the fifth lens group G5

  Conditional expression (5) defines an appropriate ratio between the focal length of the fourth lens group G4 and the focal length of the fifth lens group G5. The variable magnification optical system ZL according to the present embodiment can achieve good correction of field curvature, distortion, and spherical aberration by satisfying conditional expression (5). If the lower limit of conditional expression (5) is not reached, the refractive power of the fourth lens group G4 becomes larger than the refractive power of the fifth lens group G5, and it is difficult to correct various aberrations including spherical aberration. It becomes. In addition, the effect of this application can be made more reliable by setting the lower limit of conditional expression (5) to 0.80. On the other hand, if the upper limit of conditional expression (5) is exceeded, the refractive power of the fourth lens group G4 becomes smaller than the refractive power of the fifth lens group G5, and various aberrations including field curvature are corrected. It becomes difficult. In addition, the effect of this application can be made more reliable by setting the upper limit of conditional expression (5) to 1.45.

  Further, it is desirable that such a variable magnification optical system ZL satisfies the following conditional expression (6).

0.15 <(D45w−D45t) / fw <0.40 (6)
However,
D45w: Distance between the fourth lens group G4 and the fifth lens group G5 in the wide-angle end state D45t: Distance between the fourth lens group G4 and the fifth lens group G5 in the telephoto end state fw: Variable magnification optical system in the wide-angle end state Focal length of the entire ZL system

  Conditional expression (6) defines an appropriate range of the difference in the air gap between the fourth lens group G4 and the fifth lens group G5 in the wide-angle end state and the telephoto end state. The zoom optical system ZL according to the present embodiment satisfies the conditional expression (6), thereby suppressing a change in field curvature at the time of zooming from the wide-angle end state to the telephoto end state, and further reducing the total lens length. Can be realized. If the lower limit value of conditional expression (6) is not reached, the difference in air spacing between the fourth lens group G4 and the fifth lens group G5 between the wide-angle end state and the telephoto end state becomes small, and the telephoto end state changes from the wide-angle end state. It becomes difficult to properly correct the change in curvature of field during zooming. In addition, the effect of this application can be made more reliable by setting the lower limit of conditional expression (6) to 0.15. On the other hand, if the upper limit value of the conditional expression (6) is exceeded, the change in the air gap between the fourth lens group G4 and the fifth lens group G5 in the wide-angle end state and the telephoto end state becomes large, and in the wide-angle end state, The total lens length increases. By setting the upper limit of conditional expression (6) to 0.34, the effect of the present application can be made more reliable.

  Next, a camera which is an optical device including the variable magnification optical system ZL according to the present embodiment will be described with reference to FIG. This camera 1 is a so-called mirrorless camera of interchangeable lens provided with a variable magnification optical system ZL according to the present embodiment as a photographing lens 2. In the camera 1, light from an object (subject) (not shown) is collected by the photographing lens 2 and is on the imaging surface of the imaging unit 3 via an OLPF (Optical low pass filter) (not shown). A subject image is formed on the screen. Then, the subject image is photoelectrically converted by the photoelectric conversion element provided in the imaging unit 3 to generate an image of the subject. This image is displayed on an EVF (Electronic view finder) 4 provided in the camera 1. Thus, the photographer can observe the subject via the EVF 4.

  Further, when a release button (not shown) is pressed by the photographer, an image photoelectrically converted by the imaging unit 3 is stored in a memory (not shown). In this way, the photographer can shoot the subject with the camera 1. In the present embodiment, an example of a mirrorless camera has been described. However, a variable power optical system ZL according to the present embodiment is applied to a single-lens reflex camera that has a quick return mirror in the camera body and observes a subject with a finder optical system. Even when the camera is mounted, the same effect as the camera 1 can be obtained.

  As described above, the optical apparatus according to the present embodiment includes the variable magnification optical system ZL having the above-described configuration, thereby suppressing the change in the image size during focusing (focusing), and further It is possible to realize an optical apparatus that can satisfactorily suppress aberration fluctuations at the time of doubling and focusing.

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

  In the present embodiment, the variable magnification optical system ZL having the five-group configuration is shown, but 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.

  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, it is preferable that the third lens group G3 is a focusing lens group as described above.

  Also, by moving the lens group or partial lens group so that it has a component in the direction perpendicular to the optical axis, or rotating (swinging) in the in-plane direction including the optical axis, image blur caused by camera shake is corrected. An anti-vibration lens group may be used. 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. When the lens surface is an aspheric surface, the aspheric surface is an aspheric surface by grinding, a glass mold aspheric surface made of glass with an aspheric shape, or a composite aspheric surface made of resin with an aspheric shape on the glass surface. 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 disposed in the vicinity of the fourth lens group G4. However, the role of the aperture stop 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 variable magnification optical system ZL of the present embodiment has a variable magnification ratio of about 5 to 15 times.

  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, the first to fifth lens groups G1 to G5 are prepared by arranging each lens (step S100). Further, upon 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 changes, and the distance between the second lens group G2 and the third lens group G3 changes. The distance between the third lens group G3 and the fourth lens group G4 is changed, and the distance between the fourth lens group G4 and the fifth lens group G5 is changed (Step S200). In addition, the third lens group G3 is arranged so as to move in the optical axis direction when focusing from an object at infinity to a near object (step S300). Furthermore, the lens groups G1 to G6 are arranged so as to satisfy the conditional expression (1) (step S400).

  Specifically, in the present embodiment, for example, as shown in FIG. 1, a cemented positive lens in which a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12 are cemented in order from 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 a negative meniscus aspheric negative lens L21 having a convex surface facing the object side, a biconcave negative lens L22, and both A convex positive lens L23 is arranged to form the second lens group G2, a biconcave aspheric negative lens L31 is arranged to form the third lens group G3, and both a negative meniscus lens L41 having a convex surface facing the object side and both A cemented positive lens cemented with a convex positive lens L42, a cemented positive lens cemented with a biconvex positive lens L43 and a negative meniscus lens L44 having a concave surface facing the object side, and a biconcave aspheric surface A cemented negative lens in which a lens L45 and a positive meniscus lens L46 having a convex surface facing the object side are cemented to form a fourth lens group G4, a biconvex positive lens L51, and a biconvex positive lens L52. A cemented positive lens in which a negative meniscus lens L53 having a concave surface facing the object side is cemented to form a fifth lens group G5. The lens groups thus prepared are arranged in the above-described procedure to manufacture the variable magnification optical system ZL.

  Hereinafter, each example of the present application will be described with reference to the drawings. 1, 4 and 7 are cross-sectional views showing the configuration and refractive power distribution of the variable magnification optical system ZL (ZL1 to ZL3) according to each example. Further, in the lower part of the sectional views of these zoom optical systems ZL1 to ZL3, along the optical axes of the lens groups G1 to G5 when zooming from the wide-angle end state (W) to the telephoto end state (T) The direction of movement is indicated by an arrow.

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), K is the conic constant, and An is the nth-order aspherical coefficient, it is expressed by the following equation (a). . In the following examples, “E−n” indicates “× 10 ⁻ⁿ ”.

S (y) = (y ² / r) / {1+ (1−K × 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 right 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. The zoom optical system ZL1 shown in FIG. 1 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 first lens group having a negative refractive power. The third lens group G3 includes a fourth lens group G4 having a positive refractive power and a fifth lens group G5 having a positive refractive power.

  In the variable magnification optical system ZL1, the first lens group G1 includes, in order from the object side, a cemented positive lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12, and an object side. It is composed of a positive meniscus lens L13 having a convex surface. The second lens group G2 includes, in order from the object side, a negative meniscus aspheric negative lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, and a biconvex positive lens L23. Has been. The aspheric negative lens L21 of the second lens group G2 includes an aspheric thin plastic resin layer on the object side lens surface. The third lens group G3 includes a biconcave aspheric negative lens L31. The aspheric negative lens L31 of the third lens group G3 has an aspherical object side lens surface. The fourth lens group G4 includes, in order from the object side, a cemented positive lens of a negative meniscus lens L41 having a convex surface facing the object side and a biconvex positive lens L42, and a biconvex positive lens L43 and the object side. It consists of a cemented positive lens with a negative meniscus lens L44 having a concave surface, and a cemented negative lens with a biconcave aspheric negative lens L45 and a positive meniscus lens L46 with a convex surface facing the object side. The aspheric negative lens L45 of the fourth lens group G4 has an aspheric surface on the object side. The fifth lens group G5 includes, in order from the object side, a biconvex positive lens L51, and a cemented positive lens of a biconvex positive lens L52 and a negative meniscus lens L53 having a concave surface facing the object side. Has been.

  In the zoom optical system ZL1 according to the first example, the air gap between the first lens group G1 and the second lens group G2 increases during zooming from the wide-angle end state to the telephoto end state, and the second lens group G2 And the third lens group G3, the air gap between the third lens group G3 and the fourth lens group G4 is decreased, and the air gap between the fourth lens group G4 and the fifth lens group G5 is decreased. Each lens group from the first lens group G1 to the fifth lens group G5 moves in the object direction. The aperture stop S is disposed between the third lens group and the fourth lens group, and the aperture stop S moves together with the fourth lens group G4 during zooming.

  Further, in the variable magnification optical system ZL1 according to the first example, the third lens group G3 is moved in the object direction, thereby focusing from a long distance object to a short distance object.

  Table 1 below lists values of specifications of the variable magnification optical system ZL1 according to the first example. In Table 1, f in the overall specifications represents the focal length of the entire system, FNO represents the F number, 2ω represents the angle of view, Ymax represents the maximum image height, and TL represents the total length. Here, the total length TL represents the distance on the optical axis from the first surface of the lens surface to the image plane I when focusing on infinity. In the lens data, the first column m indicates the order (surface number) of the lens surfaces from the object side along the traveling direction of the light beam, the second column r indicates the curvature radius of each lens surface, and the third column. d is the distance on the optical axis from each optical surface to the next optical surface (surface interval). The fourth column νd and the fifth column nd are Abbe numbers and refractive indices for the d-line (λ = 587.6 nm). Is shown. Further, the radius of curvature ∞ indicates a plane, and the refractive index of air 1.000 is omitted. The surface numbers 1 to 29 shown in Table 1 correspond to the numbers 1 to 29 shown in FIG. The lens group focal length indicates the start surface and the focal length of each of the first to fifth lens groups G1 to G5.

  Here, the focal length f, the radius of curvature r, the surface interval d, and other length units listed in all the following specification values are generally “mm”, but the optical system is proportionally enlarged or proportional. Since the same optical performance can be obtained even if the image is reduced, the present invention is not limited to this. The description of these symbols and the description of the specification table are the same in the following embodiments.

(Table 1)
[Overall specifications]
Scaling ratio = 7.41
Wide angle end state Intermediate focal length state Telephoto end state f = 18.5 to 69.8 to 137.1
FNO = 3.60 to 5.48 to 5.92
2ω = 78.1 to 22.67 to 11.62
Ymax = 14.25 to 14.25 to 14.25
TL = 138.32-181.60-200.88

[Lens data]
m r d nd νd
Object ∞
1 211.4444 2.000 1.846660 23.78
2 65.7391 8.100 1.593190 67.90
3 -279.8993 0.100
4 52.3714 5.642 1.816000 46.62
5 145.4440 d5
6 * 200.0000 0.150 1.553890 38.23
7 209.8495 1.200 1.772499 49.61
8 13.1450 7.067
9 -44.1409 1.000 1.882997 40.76
10 73.4990 0.972
11 33.3323 5.131 1.846660 23.78
12 -33.7584 d12
13 * -30.5788 1.000 1.816000 46.62
14 91.7167 d14
15 ∞ 0.400 Aperture stop S
16 23.1362 1.000 1.902650 35.70
17 16.0830 4.400 1.528284 56.95
18 -34.2215 0.100
19 21.5394 4.256 1.497820 82.51
20 -30.0815 1.000 1.903660 31.27
21 -404.9013 2.791
22 * -56.4055 1.000 1.729157 54.66
23 14.6457 2.576 1.850260 32.35
24 30.4317 d24
25 306.4339 3.550 1.487490 70.40
26 -29.9125 0.100
27 62.6797 7.421 1.487490 70.40
28 -15.5000 1.301 1.882997 40.76
29 -34.7471 BF
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length 1st lens group 1 80.000
Second lens group 6 -54.309
Third lens group 13 -28.001
Fourth lens group 16 41.026
5th lens group 25 39.356

  In the zoom optical system ZL1 according to the first example, the lens surfaces of the sixth surface, the thirteenth surface, and the twenty-second surface are formed in an aspherical shape. The following Table 2 shows aspheric data, that is, the values of the conic constant K and the aspheric constants A4 to A10.

(Table 2)
[Aspherical data]
K A4 A6 A8 A10
6th surface 22.2541 2.37311E-06 -3.87675E-09 -4.25245E-11 9.37969E-14
13th surface -0.1061 9.88612E-07 -4.78288E-08 1.14604E-09 -6.39255E-12
22nd surface 0.5764 4.90141E-06 6.98139E-08 -4.01292E-10 0.00000E + 00

  In the variable magnification optical system ZL1 according to the first example, the axial air distance d5 between the first lens group G1 and the second lens group G2, and the axial air distance between the second lens group G2 and the third lens group G3. d12, the axial air gap d14 between the third lens group G3 and the fourth lens group G4, the axial air gap d24 between the fourth lens group G4 and the fifth lens group G5, and the back focus BF are as described above. In addition, it changes upon zooming. Table 3 below shows the values of the variable interval and the back focus at the respective focal lengths in the wide-angle end state, the intermediate focal length state, and the telephoto state at the time of focusing at infinity and focusing at a short distance. Note that the back focus BF indicates the distance on the optical axis from the most image side lens surface (the 29th surface in FIG. 1) to the image surface I. This description is the same in the following embodiments.

(Table 3)
[Variable interval data]
Infinity focusing state Short-distance focusing state Wide-angle end Medium telephoto end Wide-angle end Medium telephoto end
f 18.5 69.8 137.1 18.5 69.8 137.1
d5 1.500 26.470 40.393 1.500 26.470 40.393
d12 2.800 4.647 7.254 2.397 4.325 6.749
d14 24.136 7.594 3.000 24.539 7.917 3.505
d24 9.609 5.561 5.000 9.609 5.561 5.000
BF 38.02 75.07 82.97 38.02 75.07 82.97

  Table 4 below shows values corresponding to the conditional expressions in the variable magnification optical system ZL1 according to the first example. In Table 4, the combined focal length fb of the lens groups after the fourth lens group G4, the imaging magnification β3 of the third lens group G3, and the combined imaging magnification βb of the lens groups after the fourth lens group G4. For each of these, the values of the focal lengths in the wide-angle end state, the intermediate focal length state, and the telephoto state are shown. A, B, C, and D are variables shown in the above conditional expression (1), fw is the focal length of the entire system in the wide-angle end state, f1 is the focal length of the first lens group G1, and f2 Is the focal length of the second lens group G2, f3 is the focal length of the third lens group G3, f4 is the focal length of the fourth lens group G4, f5 is the focal length of the fifth lens group G5, and D45w is a wide angle. D45t represents the distance between the fourth lens group G4 and the fifth lens group G5 in the telephoto end state, and D45t represents the distance between the fourth lens group G4 and the fifth lens group G5 in the telephoto end state, respectively. The description of the above symbols is the same in the following embodiments.

(Table 4)
Wide angle end state Intermediate focal length state Telephoto end state fb 32.415 29.979 29.670
β3 0.1334 0.0616 -0.0603
βb -1.0824 -2.3284 -2.6091
[Conditional expression values]
(1) f1 / (− f2) = 1.437
(2) (A × B) / (C × D) = 1.070
(3) f3 / f2 = 0.516
(4) f1 / fw = 4.325
(5) f4 / f5 = 1.042
(6) (D45w−D45t) /fw=0.249

  Thus, the variable magnification optical system ZL1 according to the first example satisfies all the conditional expressions (1) to (6).

  FIG. 2 shows various aberration diagrams of the zoom optical system ZL1 according to the first example in the wide-angle end state, the intermediate focal length state, and the telephoto end state in the infinite focus state. FIG. 3 shows various aberration diagrams in the wide-angle end state, the intermediate focal length state, and the telephoto end state. In each aberration diagram, FNO represents an F number, NA represents a numerical aperture, and Y represents an image height. The spherical aberration diagram shows the F-number or numerical aperture value corresponding to the maximum aperture, the astigmatism diagram and the distortion diagram show the maximum image height, and the coma diagram shows the value of each image height. . d represents a d-line (λ = 587.6 nm), and g represents a g-line (λ = 435.8 nm). In the astigmatism diagram, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane. Note that the same reference numerals as in this example are also used in the aberration diagrams of the examples shown below. From these various aberration diagrams, the variable magnification optical system ZL1 according to the first example has excellent imaging performance by satisfactorily correcting various aberrations from the wide-angle end state to the telephoto end state. It can be seen that the imaging performance is excellent even during focusing.

[Second Embodiment]
FIG. 4 is a diagram showing a configuration of the variable magnification optical system ZL2 according to the second example. The zoom optical system ZL2 shown in FIG. 4 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 first lens group having a negative refractive power. The third lens group G3 includes a fourth lens group G4 having a positive refractive power and a fifth lens group G5 having a positive refractive power.

  In the variable magnification optical system ZL2, the first lens group G1 includes, in order from the object side, a cemented positive lens of a negative meniscus lens L11 having a convex surface directed toward the object side and a biconvex positive lens L12, and an object side. It is composed of a positive meniscus lens L13 having a convex surface. The second lens group G2 includes, in order from the object side, a negative meniscus aspheric negative lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, and a biconvex positive lens L23. Has been. The aspheric negative lens L21 of the second lens group G2 includes an aspheric thin plastic resin layer on the object side lens surface. The third lens group G3 includes a biconcave aspheric negative lens L31. The aspheric negative lens L31 of the third lens group G3 has an aspherical object side lens surface. The fourth lens group G4 includes, in order from the object side, a biconvex positive lens L41, a biconvex positive lens L42, and a cemented positive lens of a negative meniscus lens L43 having a concave surface facing the object side, and both It is composed of a cemented negative lens of a concave negative aspheric lens L44 and a positive meniscus lens L45 having a convex surface facing the object side. The aspheric negative lens L44 of the fourth lens group G4 has an aspheric surface on the object side. The fifth lens group G5 includes, in order from the object side, a positive meniscus lens L51 having a concave surface facing the object side, and a biconvex positive lens L52 and a negative meniscus lens L53 having a concave surface facing the object side. It consists of a positive lens.

  In the zoom optical system ZL2 according to the second example, the air gap between the first lens group G1 and the second lens group G2 increases during zooming from the wide-angle end state to the telephoto end state, and the second lens group G2 And the third lens group G3, the air gap between the third lens group G3 and the fourth lens group G4 is decreased, and the air gap between the fourth lens group G4 and the fifth lens group G5 is decreased. Each lens group from the first lens group G1 to the fifth lens group G5 moves in the object direction. The aperture stop S is disposed between the third lens group G3 and the fourth lens group G4. The aperture stop S moves together with the fourth lens group G4 during zooming.

  In the zoom optical system ZL2 according to the second example, the third lens group G3 is moved in the object direction, thereby focusing from a long distance object to a short distance object.

  Table 5 below lists values of specifications of the variable magnification optical system ZL2 of the second example. The surface numbers 1 to 28 shown in Table 5 correspond to the numbers 1 to 28 shown in FIG.

(Table 5)
[Overall specifications]
Scaling ratio = 7.42
Wide angle end state Intermediate focal length state Telephoto end state f = 18.5 to 70.5 to 137.2
FNO = 3.58 to 5.44 to 5.85
2ω = 78.1 to 22.42 to 11.57
Ymax = 14.25 to 14.25 to 14.25
TL = 139.32-181.02-199.97

[Lens data]
m r d nd νd
Object ∞
1 215.0175 2.000 1.846660 23.78
2 64.9243 8.100 1.593190 67.90
3 -376.0612 0.100
4 53.5780 5.984 1.816000 46.62
5 179.2635 d5
6 * 200.0000 0.150 1.553890 38.23
7 300.6098 1.200 1.772499 49.61
8 13.3131 6.828
9 -69.6142 1.000 1.882997 40.76
10 52.3687 1.331
11 34.6867 5.185 1.846660 23.78
12 -34.7377 d12
13 * -38.0000 1.000 1.816000 46.62
14 57.9782 d14
15 ∞ 0.400 Aperture stop S
16 29.8741 3.478 1.541617 63.72
17 -32.8953 0.100
18 23.2358 3.970 1.497820 82.51
19 -24.0338 1.000 1.903660 31.27
20 -927.0383 4.133
21 * -59.0463 1.000 1.729157 54.66
22 13.2866 2.719 1.850 260 32.35
23 29.1334 d23
24 -248.1379 3.288 1.563839 60.68
25 -29.4441 0.100
26 49.5575 7.799 1.487490 70.40
27 -16.1456 1.301 1.902650 35.70
28 -34.4375 BF
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length 1st lens group 1 79.998
Second lens group 6 -60.013
Third lens group 13 -28.000
Fourth lens group 16 42.588
Fifth lens group 24 36.790

  In the variable magnification optical system ZL2 according to the second example, the lens surfaces of the sixth surface, the thirteenth surface, and the twenty-first surface are aspherical. Table 6 below shows the aspheric data, that is, the values of the conic constant K and the aspheric constants A4 to A10.

(Table 6)
[Aspherical data]
K A4 A6 A8 A10
6th surface 22.2541 -3.64184E-06 8.39882E-09 -3.74047E-11 7.81914E-14
13th surface -1.9332 5.71903E-06 1.09072E-08 1.92007E-10 2.33529E-13
21st surface 0.5764 5.28102E-06 3.16504E-08 -2.35183E-10 0.00000E + 00

  In the variable magnification optical system ZL2 according to the second example, the axial air distance d5 between the first lens group G1 and the second lens group G2, and the axial air distance between the second lens group G2 and the third lens group G3. d12, the axial air distance d14 between the third lens group G3 and the fourth lens group G4, the axial air distance d23 between the fourth lens group G4 and the fifth lens group G5, and the back focus BF are as described above. In addition, it changes upon zooming. Table 7 below shows the values of the variable interval and the back focus at the respective focal lengths in the wide-angle end state, the intermediate focal length state, and the telephoto state at the time of focusing at infinity and focusing at a short distance.

(Table 7)
[Variable interval data]
Infinity focusing state Short-distance focusing state Wide-angle end Medium telephoto end Wide-angle end Medium telephoto end
f 18.5 70.5 137.2 18.5 70.5 137.2
d5 1.500 26.692 40.261 1.500 26.692 40.261
d12 2.837 4.356 7.527 2.416 4.012 6.987
d14 24.771 7.722 3.000 25.192 8.065 3.541
d23 10.025 5.509 5.000 10.025 5.509 5.000
BF 38.02 74.58 82.02 38.02 74.58 82.02

  Table 8 below shows values corresponding to the conditional expressions in the variable magnification optical system ZL2 according to the second example.

(Table 8)
Wide-angle end state Intermediate focal length state Telephoto end state fb 33.565 30.604 30.303
β3 0.1117 0.0349 -0.0925
βb -1.0548 -2.2679 -2.5273
[Conditional expression values]
(1) f1 / (− f2) = 1.333
(2) (A × B) / (C × D) = 1.070
(3) f3 / f2 = 0.467
(4) f1 / fw = 4.324
(5) f4 / f5 = 1.158
(6) (D45w−D45t) /fw=0.272

  Thus, the zoom optical system ZL2 according to the second example satisfies all the conditional expressions (1) to (6).

  FIG. 5 shows various aberration diagrams of the variable magnification optical system ZL2 according to the second example in the wide-angle end state, the intermediate focal length state, and the telephoto end state in the infinite focus state. FIG. 6 shows various aberration diagrams in the wide-angle end state, the intermediate focal length state, and the telephoto end state. From these various aberration diagrams, the variable magnification optical system ZL2 according to the second example has excellent imaging performance by satisfactorily correcting various aberrations from the wide-angle end state to the telephoto end state. It can be seen that the imaging performance is excellent even during focusing.

[Third embodiment]
FIG. 7 is a diagram showing a configuration of the variable magnification optical system ZL3 according to the third example. The zoom optical system ZL3 shown in FIG. 7 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 first lens group having a negative refractive power. The third lens group G3 includes a fourth lens group G4 having a positive refractive power and a fifth lens group G5 having a positive refractive power.

  In the variable magnification optical system ZL3, the first lens group G1 includes, in order from the object side, a cemented positive lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12, and an object side. It is composed of a positive meniscus lens L13 having a convex surface. The second lens group G2 includes, in order from the object side, a negative meniscus aspheric negative lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, and a biconvex positive lens L23. Has been. The aspheric negative lens L21 of the second lens group G2 includes an aspheric thin plastic resin layer on the object side lens surface. The third lens group G3 includes a biconcave aspheric negative lens L31. The aspheric negative lens L31 of the third lens group G3 has an aspherical object side lens surface. The fourth lens group G4 includes, in order from the object side, a cemented positive lens of a negative meniscus lens L41 having a convex surface facing the object side and a biconvex positive lens L42, and a biconvex positive lens L43 and the object side. It consists of a cemented positive lens with a negative meniscus lens L44 having a concave surface, and a cemented negative lens with a biconcave aspheric negative lens L45 and a positive meniscus lens L46 with a convex surface facing the object side. The aspheric negative lens L45 of the fourth lens group G4 has an aspheric surface on the object side. The fifth lens group G5 includes, in order from the object side, a positive meniscus lens L51 having a concave surface facing the object side, a positive lens L52 having a biconvex shape, and a cemented positive lens having a negative meniscus lens L53 having a concave surface facing the object side. And a negative meniscus lens L54 having a concave surface facing the object side.

  In the variable magnification optical system ZL3 according to the third example, the air gap between the first lens group G1 and the second lens group G2 increases upon zooming from the wide-angle end state to the telephoto end state, and the second lens group G2 And the third lens group G3, the air gap between the third lens group G3 and the fourth lens group G4 is decreased, and the air gap between the fourth lens group G4 and the fifth lens group G5 is decreased. Each lens group from the first lens group G1 to the fifth lens group G5 moves in the object direction. The aperture stop S is disposed between the third lens group G3 and the fourth lens group G4. The aperture stop S moves together with the fourth lens group G4 during zooming.

  In the zoom optical system ZL3 according to the third example, the third lens group G3 is moved in the object direction, thereby focusing from a long distance object to a short distance object.

  Table 9 below provides values of specifications of the variable magnification optical system ZL3 of the third example. The surface numbers 1 to 31 shown in Table 9 correspond to the numbers 1 to 31 shown in FIG.

(Table 9)
[Overall specifications]
Scaling ratio = 7.41
Wide angle end state Intermediate focal length state Telephoto end state f = 18.5 to 69.5 to 137.1
FNO = 3.53 to 5.63 to 5.88
2ω = 78.1 to 22.81 to 11.60
Ymax = 14.25 to 14.25 to 14.25
TL = 138.31-183.34-201.92

[Lens data]
m r d nd νd
Object ∞
1 240.0000 2.000 1.846660 23.78
2 67.9585 8.100 1.593190 67.90
3 -228.3587 0.100
4 50.9478 5.604 1.816000 46.62
5 130.7206 d5
6 * 200.0000 0.150 1.553890 38.23
7 220.2039 1.200 1.772499 49.61
8 13.0490 7.071
9 -46.1818 1.000 1.882997 40.76
10 66.5635 1.055
11 35.4681 5.226 1.846660 23.78
12 -30.8403 d12
13 * -28.9787 1.000 1.816000 46.62
14 109.6730 d14
15 ∞ 0.400 Aperture stop S
16 24.8684 1.000 1.902650 35.70
17 16.7163 4.400 1.562857 53.65
18 -34.2463 0.100
19 18.0955 4.364 1.497820 82.51
20 -31.4489 1.000 1.903660 31.27
21 91.7396 2.500
22 * -86.5271 1.000 1.729157 54.66
23 12.5188 2.748 1.850260 32.35
24 24.8338 d24
25 -402.7374 3.237 1.626788 59.07
26 -29.3596 0.100
27 38.7545 7.834 1.487490 70.40
28 -15.5000 1.301 1.882997 40.76
29 -27.6430 0.263
30 -40.1683 1.000 1.882997 40.76
31 -74.5264 BF
Image plane ∞

[Lens focal length]
Lens group Start surface Focal length 1st lens group 1 80.000
Second lens group 6 -59.191
Third lens group 13 -28.000
Fourth lens group 16 46.114
5th lens group 25 34.271

  In the variable magnification optical system ZL3 according to the third example, the lens surfaces of the sixth surface, the thirteenth surface, and the twenty-second surface are formed in an aspherical shape. Table 10 below shows the aspheric data, that is, the values of the conic constant K and the aspheric constants A4 to A10.

(Table 10)
[Aspherical data]
K A4 A6 A8 A10
6th surface 22.2541 2.52148E-06 -8.96525E-09 -3.86729E-11 1.20386E-13
13th surface -0.0609 1.13314E-06 -1.25083E-09 4.17478E-10 -1.62820E-12
22nd surface 0.5764 5.81857E-06 6.67215E-08 -4.14394E-10 0.00000E + 00

  In the variable magnification optical system ZL3 according to the third example, the axial air distance d5 between the first lens group G1 and the second lens group G2, and the axial air distance between the second lens group G2 and the third lens group G3. d12, the axial air gap d14 between the third lens group G3 and the fourth lens group G4, the axial air gap d24 between the fourth lens group G4 and the fifth lens group G5, and the back focus BF are as described above. In addition, it changes upon zooming. Table 11 below shows the values of the variable interval and the back focus at the respective focal lengths in the wide-angle end state, the intermediate focal length state, and the telephoto state at the time of focusing on infinity and focusing on a short distance.

(Table 11)
[Variable interval data]
Infinity focusing state Short-distance focusing state Wide-angle end Medium telephoto end Wide-angle end Medium telephoto end
f 18.5 69.5 137.1 18.5 69.5 137.1
d5 1.500 24.534 40.460 1.500 24.534 40.460
d12 2.808 4.059 7.370 2.401 3.766 6.851
d14 23.985 7.275 3.000 24.392 7.569 3.519
d23 8.253 5.298 5.000 8.253 5.298 5.000
BF 38.01 78.42 82.34 38.01 78.42 82.34

  Table 12 below shows values corresponding to the conditional expressions in the variable magnification optical system ZL3 according to the third example.

(Table 12)
Wide angle end state Intermediate focal length state Telephoto end state fb 31.872 30.080 29.910
β3 0.1149 0.0515 -0.0829
βb -1.0734 -2.4362 -2.5771
[Conditional expression values]
(1) f1 / (− f2) = 1.352
(2) (A × B) / (C × D) = 1.0073
(3) f3 / f2 = 0.473
(4) f1 / fw = 4.325
(5) f4 / f5 = 1.346
(6) (D45w−D45t) /fw=0.176

  Thus, the variable magnification optical system ZL3 according to the third example satisfies all the conditional expressions (1) to (6).

  FIG. 8 shows various aberration diagrams of the variable magnification optical system ZL3 according to the third example in the wide-angle end state, the intermediate focal length state, and the telephoto end state in the infinite focus state. FIG. 9 shows various aberration diagrams in the wide-angle end state, the intermediate focal length state, and the telephoto end state. From these various aberration diagrams, the variable magnification optical system ZL3 according to the third example has excellent imaging performance by satisfactorily correcting various aberrations from the wide-angle end state to the telephoto end state. It can be seen that the imaging performance is excellent even during focusing.

  Here, each said Example has shown one specific example of this invention, and this invention is not limited to these.

DESCRIPTION OF SYMBOLS 1 Camera (optical apparatus) ZL (ZL1, ZL2) Variable magnification optical system G1 1st lens group G2 2nd lens group G3 3rd lens group G4 4th lens group G5 5th lens group

Claims (11)

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 negative refractive power;
A fourth lens group having a positive refractive power;
A fifth lens group having a positive refractive power,
During zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group changes, and the distance between the second lens group and the third lens group changes, The distance between the third lens group and the fourth lens group changes, and the distance between the fourth lens group and the fifth lens group changes,
When focusing from an object at infinity to an object at a short distance, the third lens group moves in the optical axis direction,
A variable magnification optical system characterized by satisfying the following condition:
1.10 <f1 / (− f2) <2.00
However,
f1: Focal length of the first lens group f2: Focal length of the second lens group   2. The zoom optical system according to claim 1, wherein the first lens unit moves in the object direction when zooming from the wide-angle end state to the telephoto end state.   In 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 distance between the third lens group and the fourth lens group decreases. The variable power optical system according to claim 1 or 2, characterized in that: The zoom lens system according to any one of claims 1 to 3, wherein a condition of the following formula is satisfied.
0.990 <(A × B) / (C × D) <1.013
However,
A = f3 × (1−β3w) ² × (1 + β3w) × βbw ² −Δ × β3w ²
B = fbw × (1−βbw) + Δ
C = f3 × (1−β3w) ² × (1 + β3w) × βbw ² −Δ × β3w
D = fbw × (1−βbw) + Δ / βbw
Δ = Ymax / 50
β3w: Imaging magnification of the third lens group in the wide-angle end state βbw: Composite imaging magnification of the lens group after the fourth lens group in the wide-angle end state Ymax: Maximum image height f3: Focal length of the third lens group fbw: the combined focal length of the lens units after the fourth lens unit in the wide-angle end state   During zooming from the wide-angle end state to the telephoto end state, the fourth lens group and the fifth lens group move in the object direction, and the distance between the second lens group and the third lens group increases. 5. The variable magnification optical system according to claim 1, wherein a distance between the fourth lens group and the fifth lens group is reduced. The zoom lens system according to any one of claims 1 to 5, wherein a condition of the following formula is satisfied.
0.35 <f3 / f2 <0.90
However,
f3: focal length of the third lens group The zoom lens system according to any one of claims 1 to 6, wherein a condition of the following formula is satisfied.
3.50 <f1 / fw <5.50
However,
fw: focal length of the entire system of the variable magnification optical system in the wide-angle end state The zoom lens system according to any one of claims 1 to 7, wherein a condition of the following formula is satisfied.
0.72 <f4 / f5 <1.45
However,
f4: focal length of the fourth lens group f5: focal length of the fifth lens group The zoom lens system according to any one of claims 1 to 8, wherein a condition of the following formula is satisfied.
0.15 <(D45w−D45t) / fw <0.40
However,
D45w: the distance between the fourth lens group and the fifth lens group in the wide-angle end state D45t: the distance between the fourth lens group and the fifth lens group in the telephoto end state fw: the variable power optical system in the wide-angle end state Focal length of the whole system   An optical apparatus comprising the variable magnification optical system 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 negative refractive power, and a fourth lens having a positive refractive power A variable magnification optical system having a group and a fifth lens group having a positive refractive power,
During zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group changes, and the distance between the second lens group and the third lens group changes, The distance between the third lens group and the fourth lens group is changed, and the distance between the fourth lens group and the fifth lens group is changed.
When focusing from an object at infinity to an object at a short distance, the third lens group is arranged to move in the optical axis direction,
A method of manufacturing a variable magnification optical system, wherein the zoom lens is disposed so as to satisfy the condition of the following formula.
1.10 <f1 / (− f2) <2.00
However,
f1: Focal length of the first lens group f2: Focal length of the second lens group

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