JP2010169982A - Zoom lens, optical device equipped with the zoom lens and method for manufacturing the zoom lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a zoom lens having excellent imaging performance, an optical device equipped with the zoom lens, and a method for manufacturing the zoom lens. <P>SOLUTION: The zoom lens ZL mounted on an electronic still camera 1 or the like has 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; and a fourth lens group G4 having positive refractive power. Provided that a curvature radius of an image-side surface of a cemented lens in the third lens group G3 is denoted as r3F, and a curvature radius of an object-side surface of a negative meniscus lens L34 in the third lens group G3 is denoted as r3R, the zoom lens satisfies a conditional expression: r3R<0-2.00<(r3R+r3F)/(r3R-r3F)<1.00. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a zoom lens, an optical apparatus including the zoom lens, and a method for manufacturing the zoom lens.

  Conventionally, a positive / negative positive / positive four-group type zoom lens is known (for example, see Patent Document 1). The positive, negative, positive, and positive four-group type zoom lens includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power in order from the object side. It is composed of four lens groups including a fourth lens group having positive refractive power. When zooming from the wide-angle end state (the shortest focal length) to the telephoto end state (the longest focal length), at least the first lens group and the third lens group move toward the object side. Today, digital still cameras and video cameras using solid-state image sensors have become larger in diameter because the area of each light-receiving element has become smaller with the recent increase in the density of light-receiving elements. At the same time, high optical performance was required. In addition, there is a demand for a digital still camera that has a high zoom ratio and is small and excellent in portability for convenience of photographing.

JP-A-1-352400

  However, in a light receiving element with an increased number of pixels, the conventional optical system cannot easily cope with a wider light receiving area, and the lens system tends to be enlarged due to a large aperture. As a result of the increase in size, portability has resulted in inconvenience. In addition, there is a growing demand for a zoom lens having a wide angle of view in order to expand the possibilities of photographer's shooting expression. The use of a wider angle of view makes it possible to enjoy shooting with a higher degree of freedom, but it is extremely difficult to achieve a high zoom ratio, wide angle of view, and high image quality. There was a problem that the system would become larger.

  The present invention has been made in view of such problems, and provides a zoom lens capable of obtaining a compact and high imaging performance, an optical apparatus including the zoom lens, and a method for manufacturing the zoom lens. With the goal.

In order to solve the above problems, a zoom lens 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 first lens group having a positive refractive power. 3 lens groups and a fourth lens group having a positive refractive power. The third lens group includes, in order from the object side, a first positive lens, a cemented lens of a second positive lens and a negative lens, and a negative meniscus lens, and a surface on the image side of the cemented lens of the third lens group. Is r3F, and the curvature radius of the object side surface of the negative meniscus lens in the third lens group is r3R, r3R <0
−2.00 <(r3R + r3F) / (r3R−r3F) <1.00
It is configured to satisfy

  Further, in such a zoom lens, the first positive lens in the third lens group is arranged with the convex surface facing the object side, and the cemented lens has the second positive lens with the convex surface facing the object side, and the negative lens is Preferably, the negative meniscus lens is cemented with the concave surface facing the image side, and the negative meniscus lens is disposed with the convex surface facing the image side.

Further, in such a zoom lens, when the focal length of the entire lens system in the wide-angle end state is fw and the focal length of the third lens group is f3, the following expression 0.10 <fw / f3 <0.50
It is preferable to satisfy the following conditions.

  Further, in such a zoom lens, 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 changes, and the second lens group and the third lens group It is preferable that at least the first lens group and the fourth lens group are moved to the object side so that the distance changes and the distance between the third lens group and the fourth lens group changes.

  Also, in such a zoom lens, 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 distance is decreased and the distance between the third lens group and the fourth lens group is decreased.

Further, in such a zoom lens, when the focal length of the first lens group is f1 and the focal length of the second lens group is f2, the following expression 6.00 <f1 / (− f2) <7.80
It is preferable to satisfy the following conditions.

  Such a zoom lens preferably has an aperture stop between the second lens group and the third lens group.

  In such a zoom lens, it is preferable that the cemented lens in the third lens group has a negative refractive power.

  In addition, such a zoom lens preferably has at least one aspheric lens in the third lens group.

  In such a zoom lens, it is preferable that the image side lens surface of the negative meniscus lens located on the image side of the cemented lens of the third lens group is formed in an aspherical shape.

Also, in such a zoom lens, when the focal length of the third lens group is f3 and the focal length of the fourth lens group is f4, the following expression 0.15 <f3 / f4 <2.75
It is preferable to satisfy the following conditions.

In such a zoom lens, when the focal length of the first lens group is f1 and the focal length of the third lens group is f3, the following expression 0.85 <f1 / f3 <2.74 is satisfied.
It is preferable to satisfy the following conditions.

  In such a zoom lens, it is preferable to focus on a short-distance object by moving at least a part of the second lens group along the optical axis.

  In addition, it is preferable that such a zoom lens moves so that at least a part of the third lens group has a component in a direction substantially perpendicular to the optical axis.

  An optical apparatus according to the present invention includes any one of the above-described zoom lenses that forms an image of an object on a predetermined image plane.

The zoom lens manufacturing method 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 third lens having a positive refractive power. A zoom lens manufacturing method including a lens group and a fourth lens group having a positive refractive power, in order from the object side, a first positive lens, and a cemented lens of a second positive lens and a negative lens; A negative meniscus lens is disposed in the third lens group, the curvature radius of the third lens group on the image side of the cemented lens of the third lens group is r3F, and the curvature of the negative meniscus lens in the third lens group on the object side When the radius is r3R, the following formula r3R <0
−2.00 <(r3R + r3F) / (r3R−r3F) <1.00
Arrange to satisfy the conditions of

  When the zoom lens according to the present invention, the optical apparatus including the zoom lens, and the method for manufacturing the zoom lens are configured as described above, a small and high imaging performance can be obtained.

It is refractive power arrangement | positioning of the zoom lens by this embodiment. It is sectional drawing which shows the structure of the zoom lens by 1st Example. FIG. 3A is a diagram illustrating various aberrations of the first example, where FIG. 3A is an aberration diagram in an infinite focus state in a wide-angle end state, and FIG. 3B is an aberration diagram in an infinite focus state in an intermediate shooting distance state 1; (C) is an aberration diagram in the infinite focus state in the intermediate shooting distance state 2, and (d) is various aberrations in the infinite focus state in the telephoto end state. It is sectional drawing which shows the structure of the zoom lens by 2nd Example. FIG. 6 is a diagram illustrating various aberrations of the second example, where (a) is an aberration diagram in an infinite focus state in a wide-angle end state, and (b) is an aberration diagram in an infinite focus state in an intermediate shooting distance state 1; (C) is an aberration diagram in the infinite focus state in the intermediate shooting distance state 2, and (d) is various aberrations in the infinite focus state in the telephoto end state. It is sectional drawing which shows the structure of the zoom lens by 3rd Example. FIG. 6A is a diagram illustrating various aberrations of the third example, FIG. 5A is an aberration diagram in an infinite focus state in a wide-angle end state, and FIG. 5B is an aberration diagram in an infinite focus state in an intermediate shooting distance state 1; (C) is an aberration diagram in the infinite focus state in the intermediate shooting distance state 2, and (d) is various aberrations in the infinite focus state in the telephoto end state. It is sectional drawing which shows the structure of the zoom lens by 4th Example. FIG. 9A is a diagram illustrating various aberrations of the fourth example, in which FIG. 10A is an aberration diagram in the infinite focus state in the wide-angle end state, and FIG. 10B is an aberration diagram in the infinite focus state in the intermediate shooting distance state 1; (C) is an aberration diagram in the infinite focus state in the intermediate shooting distance state 2, and (d) is various aberrations in the infinite focus state in the telephoto end state. It is sectional drawing which shows the structure of the zoom lens by 5th Example. FIG. 6A is a diagram illustrating various aberrations of the fifth example, FIG. 5A is an aberration diagram in an infinite focus state in a wide-angle end state, and FIG. 5B is an aberration diagram in an infinite focus state in an intermediate shooting distance state 1; (C) is an aberration diagram in the infinite focus state in the intermediate shooting distance state 2, and (d) is various aberrations in the infinite focus state in the telephoto end state. It is sectional drawing which shows the structure of the zoom lens by 6th Example. FIG. 9A is a diagram illustrating various aberrations of the sixth example, FIG. 10A is an aberration diagram in an infinite focus state in a wide-angle end state, and FIG. 9B is an aberration diagram in an infinite focus state in an intermediate shooting distance state 1; (C) is an aberration diagram in the infinite focus state in the intermediate shooting distance state 2, and (d) is various aberrations in the infinite focus state in the telephoto end state. 1 is a cross-sectional view of a digital single-lens reflex camera equipped with a zoom lens according to the present embodiment. 5 is a flowchart for explaining a method of manufacturing a zoom lens according to the present embodiment.

  Hereinafter, preferred embodiments of the present application will be described with reference to the drawings. As shown in FIG. 1, the zoom lens ZL has, in order from the object side, a first lens group G1 having a positive refractive index, a second lens group G2 having a negative refractive index, and a positive refractive power. The third lens group G3 includes a fourth lens group G4 having a positive refractive power. The zoom lens ZL has a first lens group G1 and a second lens group G2 when the focal length changes from the wide-angle end state (the state with the shortest focal length) to the telephoto end state (the state with the longest focal length). At least the first lens group G1 so that the distance between the second lens group G2 and the third lens group G3 decreases and the distance between the third lens group G3 and the fourth lens group G4 decreases. And the fourth lens group G4 moves to the object side. With this configuration, the zoom lens ZL can obtain excellent imaging performance while having a wide angle of view and a high magnification.

  Next, the function of each lens group will be described. The first lens group G1 has an effect of converging the light beam, and is arranged so that the off-axis light beam passes away from the optical axis by being as close as possible to the image plane in the wide-angle end state. The lens diameter is reduced. On the other hand, in the telephoto end state, the lens system is moved to the object side so as to greatly widen the distance from the second lens group G2, thereby enhancing the convergence effect and shortening the entire length of the lens system.

  The second lens group G2 has an effect of enlarging the image of the subject formed by the first lens group G1, and as it goes from the wide-angle end state to the telephoto end state, the first lens group G1 and the second lens group G2 The focal length is changed by increasing the magnification by increasing the interval.

  The third lens group G3 functions to converge the light beam expanded by the second lens group G2, and in order to achieve high performance, the third lens group G3 is preferably composed of a plurality of lens groups. .

  The fourth lens group G4 has a function of further converging the luminous flux converged by the third lens group G3, and when changing the focal length, the interval between the third lens group G3 and the fourth lens group G4 is positively changed. By changing to, fluctuations in the image plane with respect to changes in focal length can be suppressed.

  In order to further improve the performance of the zoom lens ZL, the third lens group G3 includes, in order from the object side, a first positive lens L31, a cemented lens CL31 of a second positive lens L32, and a negative lens L33. And a negative meniscus lens L34, and the object side surface of the negative meniscus lens L34 in the third lens group G3 is preferably disposed with the concave surface facing the object side. That is, in this zoom lens ZL, the radius of curvature of the image side surface of the cemented lens CL31 of the third lens group G3 is r3F, and the radius of curvature of the object side surface of the negative meniscus lens L34 in the third lens group G3 is r3R. In this case, it is desirable to satisfy the following conditional expressions (1) and (2).

r3R <0 (1)
−2.00 <(r3R + r3F) / (r3R−r3F) <1.00 (2)

  Conditional expression (1) is a conditional expression for defining the radius of curvature of the object side surface of the most image side lens of the third lens group G3. Satisfying this conditional expression (1), that is, by disposing the object-side surface of the most image-side lens of the third lens group G3 with the concave surface facing the object side, from the wide-angle end state to the telephoto end state It is possible to satisfactorily correct fluctuations in spherical aberration and coma that occur when the focal length is changed.

  Conditional expression (2) defines the ratio between the radius of curvature of the image side surface of the cemented lens SL31 and the radius of curvature of the object side surface of the lens closest to the image side of the third lens group G3. It is a conditional expression for satisfactorily correcting coma and field curvature that occur in the third lens group G3 alone. If the upper limit value of the conditional expression (2) is exceeded, coma aberration and field curvature generated by the third lens group G3 alone cannot be corrected. Moreover, since distortion also increases, it is not preferable. In order to secure the effect of the present application, it is preferable to set the upper limit of conditional expression (2) to 0.70. In order to further secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (2) to 0.30. In order to further secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (2) to 0.15. On the other hand, if the lower limit of conditional expression (2) is not reached, the coma aberration generated by the third lens group G3 alone becomes too large, and the performance at the shortest shooting distance is deteriorated. In order to secure the effect of the present application, it is preferable to set the lower limit of conditional expression (2) to -1.70. In order to further secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (2) to -1.50. In order to further secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (2) to -1.00.

  In the zoom lens ZL, it is desirable to configure the third lens group G3 as follows for further performance enhancement. That is, in order to satisfactorily correct the on-axis aberration generated by the third lens group G3 alone, as described above, the third lens group G3 includes the first positive lens L31 and the second positive lens in order from the object side. It is desirable that the lens is composed of a cemented lens CL31 of a lens L32 and a negative lens L33, and a negative meniscus lens L34. At this time, an aperture stop S is provided between the second lens group G2 and the third lens group G3, and when zooming from the wide-angle end state to the telephoto end state, the aperture stop S is in contact with the third lens group G3. It is desirable to be configured to move together.

  In the zoom lens ZL, it is desirable to configure the third lens group G3 as follows for further performance enhancement. That is, in order to satisfactorily correct the axial aberration generated by the third lens group G3 alone, the first positive lens L31 in the third lens group G3 is disposed with the convex surface facing the object side, and the cemented lens CL31. It is desirable that the second positive lens L32 is cemented with the convex surface facing the object side, the negative lens L33 is cemented with the concave surface facing the image side, and the negative meniscus lens L34 is disposed with the convex surface facing the image side.

  In the zoom lens ZL, it is desirable that the following conditional expression (3) is satisfied when the focal length of the entire lens system in the wide-angle end state is fw and the focal length of the third lens group G3 is f3. .

0.10 <fw / f3 <0.50 (3)

  Conditional expression (3) is a conditional expression for defining the focal length of the third lens group G3. Exceeding the upper limit of conditional expression (3) is not preferable because the refractive power of the third lens group G3 increases and the spherical aberration generated by the third lens group G3 alone increases. In order to secure the effect of the present application, it is preferable to set the upper limit of conditional expression (3) to 0.47. In order to further secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (3) to 0.44. In order to further secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (3) to 0.40. On the other hand, if the lower limit value of conditional expression (3) is not reached, the refractive power of the third lens group G3 becomes weak and coma aberration and field curvature become large, which is not preferable. In order to secure the effect of the present application, it is preferable to set the lower limit of conditional expression (3) to 0.15. In order to further secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (3) to 0.17. In order to further secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (3) to 0.20.

  In the zoom lens ZL, it is preferable that the following conditional expression (4) is satisfied when the focal length of the first lens group G1 is f1 and the focal length of the second lens group G2 is f2.

6.00 <f1 / (-f2) <7.80 (4)

  Conditional expression (4) is a conditional expression for defining an appropriate range for the focal length ratio between the first lens group G1 and the second lens group G2. If the upper limit value of the conditional expression (4) is exceeded, the refractive power of the first lens group G1 becomes relatively weak, and the first lens group G1 cannot effectively contribute to zooming. In addition, the amount of movement of the first lens group G1 increases, and the variation in spherical aberration that occurs in the first lens group G1 during zooming increases. As a result, it becomes difficult to suppress a decrease in performance in the entire zoom range from the wide-angle end state to the telephoto end state. Furthermore, since the refractive power of the second lens group G2 becomes relatively strong, the occurrence of coma aberration cannot be suppressed, and high optical performance cannot be obtained. In order to secure the effect of the present application, it is preferable to set the upper limit of conditional expression (4) to 7.60. In order to further secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (4) to 7.40. On the other hand, if the lower limit of conditional expression (4) is not reached, the refractive power of the first lens group G1 becomes relatively strong, and the off-axis light beam and the optical axis incident on the first lens group G1 at the wide angle side. If the angle formed by the lens is reduced and a wide angle of view is to be realized, the outer diameter of the first lens group G1 is increased, which is contrary to miniaturization. Further, since the refractive power of the second lens group G2 becomes relatively weak, the second lens group G2 cannot effectively contribute to zooming, and a high zoom ratio cannot be secured. Further, it is not preferable because correction of coma aberration becomes difficult. In order to secure the effect of the present application, it is preferable to set the lower limit of conditional expression (4) to 6.20. In order to further secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (4) to 6.40.

  In addition, it is desirable that the zoom lens ZL is configured as follows in the third lens group G3 for further enhancement of performance. That is, it is desirable that the cemented lens CL31 in the third lens group G3 has a negative refractive power. By having negative refracting power in this way, an appropriate refracting power is arranged in the third lens group G3, and spherical aberration and field curvature occurring in the third lens group G3 alone can be corrected more satisfactorily. Can do.

  The zoom lens ZL preferably includes at least one aspheric lens in the third lens group G3. Here, by disposing an aspherical lens in the third lens group G3, coma aberration and field curvature generated by the third lens group G3 alone can be favorably corrected.

  Further, in the present zoom lens ZL, the image side lens surface of the negative meniscus lens L34 located on the image side of the cemented lens CL31 of the third lens group G3 is made non-balanced in order to balance higher performance and smaller size. It is desirable that it be formed in a spherical shape. With such a configuration, it is possible to satisfactorily correct spherical aberration and field curvature.

  The zoom lens ZL preferably satisfies the following conditional expression (5) when the focal length of the third lens group G3 is f3 and the focal length of the fourth lens group G4 is f4.

0.15 <f3 / f4 <2.75 (5)

  Conditional expression (5) is a conditional expression for defining an appropriate range for the focal length ratio between the third lens group G3 and the fourth lens group G4. If the upper limit of conditional expression (5) is exceeded, the refractive power of the third lens group G3 becomes relatively weak, and the total lens length becomes large. In addition, the spherical aberration and the coma aberration generated in the third lens group G3 are insufficiently corrected, and the desired optical performance cannot be achieved. In order to further secure the effect of the present application, it is preferable to set the upper limit of conditional expression (5) to 2.50. In order to further secure the effect of the present application, it is preferable to set the upper limit of conditional expression (5) to 2.30. In order to further secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (5) to 2.10. On the other hand, if the lower limit of conditional expression (5) is not reached, the refractive power of the second lens group G2 becomes strong and the divergence action becomes strong in order to ensure the back focus in the wide-angle end state. As a result, the light beam incident on the third lens group G3 spreads and the spherical aberration generated by the third lens group G3 alone increases, which is not preferable. In order to secure the effect of the present application, it is preferable to set the lower limit of conditional expression (5) to 0.30. In order to further secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (5) to 0.50. In order to further secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (5) to 0.70.

  The zoom lens ZL preferably satisfies the following conditional expression (6) when the focal length of the first lens group G1 is f1 and the focal length of the third lens group G3 is f3.

0.85 <f1 / f3 <2.74 (6)

  Conditional expression (6) is a conditional expression for defining an appropriate range for the focal length ratio between the first lens group G1 and the third lens group G3. If the upper limit value of the conditional expression (6) is exceeded, the refractive power of the first lens group G1 becomes relatively weak, and the first lens group G1 cannot effectively contribute to zooming. As a result, it becomes difficult to reduce the overall length. Further, since the refractive power of the third lens group G3 becomes relatively strong, it becomes impossible to suppress the occurrence of spherical aberration and coma aberration, and high optical performance cannot be obtained, which is not preferable. In order to further secure the effect of the present application, it is preferable to set the upper limit of conditional expression (6) to 2.50. In order to further secure the effect of the present application, it is preferable to set the upper limit of conditional expression (6) to 2.30. On the other hand, if the lower limit value of conditional expression (6) is not reached, the refractive power of the first lens group G1 becomes relatively strong, and the off-axis rays incident on the first lens group G1 and the optical axis on the wide angle side. If the angle formed is small and an attempt is made to realize a wide angle of view, the outer diameter of the first lens group G1 becomes large, which is contrary to miniaturization. Further, since the refractive power of the third lens group G3 becomes relatively weak, it is not preferable because it becomes difficult to correct coma aberration and field curvature generated in the third lens group G3 alone. In order to secure the effect of the present application, it is preferable to set the lower limit of conditional expression (6) to 1.00. In order to further secure the effect of the present application, it is preferable to set the lower limit of conditional expression (6) to 1.20. In order to further secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (6) to 1.40.

  FIG. 14 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 zoom lens ZL. In this camera 1, light from an object (subject) (not shown) is collected by the taking lens 2 (zoom lens ZL) and imaged on the focusing screen 4 via the quick return mirror 3. The light imaged on the focusing screen 4 is reflected a plurality of times in the pentaprism 5 and guided to the eyepiece lens 6. Thus, the photographer can observe the object (subject) image as an erect image through the eyepiece 6.

  Further, when a release button (not shown) is pressed by the photographer, the quick return mirror 3 is retracted out of the optical path, and light of an object (subject) (not shown) condensed by the photographing lens 2 is captured on the image sensor 7. Form an image. Thereby, the light from the object (subject) is captured by the image sensor 7 and recorded as an object (subject) image in a memory (not shown). In this way, the photographer can shoot an object (subject) with the camera 1. The camera 1 shown in FIG. 14 may hold the zoom lens ZL in a detachable manner, or may be formed integrally with the zoom lens 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.

  This zoom lens ZL uses a blur detection system for detecting blur in the lens system and a drive means as a lens system in order to prevent a shooting failure due to image blur caused by camera shake or the like that tends to occur in a high-magnification zoom lens. The image blur (image plane position) caused by the blur of the lens system detected by the blur detection system by decentering all or part of one of the lens groups constituting the combination and lens system as a shift lens group The image blur can be corrected by driving the shift lens group by the driving means and shifting the image so as to correct the fluctuation of the image. As described above, the zoom lens ZL can function as a so-called vibration-proof optical system. In particular, it is preferable that at least a part of the second lens group G2 or at least a part of the third lens group G3 is an anti-vibration lens group.

  In this embodiment, the lens system is composed of five movable groups. However, another lens group is added between the lens groups, or the lens system is adjacent to the image side or the object side of the lens system. It is also possible to add these lens groups.

  In the present embodiment, the zoom lens ZL having a four-group configuration is shown, but the above-described configuration conditions and the like can also be applied to other group configurations such as a five-group configuration. Further, a configuration in which a lens or a lens group is added on the object side or a configuration in which a lens or a lens group is added on the most image side may be used. The lens group indicates a portion having at least one lens separated by an air interval that changes at the time of 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 at least a part of the second lens group G2 or at least a part of the fourth lens group G4 is a focusing 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.

  As described above, the aperture stop S is preferably disposed between the second lens group G2 and the third lens group G3. However, without providing a member as the aperture stop S, the aperture stop S plays a role in the lens frame. You may substitute.

  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.

  In the zoom lens ZL of the present embodiment, it is preferable that the first lens group G1 has two positive lens components. In the first lens group G1, it is preferable that lens components are arranged in order of positive and negative in order from the object side with an air gap interposed therebetween. Alternatively, the first lens group G1 preferably has two positive lens components and one negative lens component. In the first lens group G1, it is preferable to dispose the lens components in the order of negative positive / negative in order from the object side with an air gap interposed therebetween.

  In the zoom lens ZL of the present embodiment, it is preferable that the second lens group G2 has one positive lens component and two negative lens components. In the second lens group G2, it is preferable to arrange the lens components in order of negative and positive in order from the object side with an air gap interposed therebetween. Alternatively, 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.

  In the zoom lens ZL of the present embodiment, it is preferable that the third lens group G3 has one positive lens component and two negative lens components. In the third lens group G3, it is preferable to arrange the lens components in order of positive and negative in order from the object side with an air gap therebetween.

  Furthermore, in the zoom lens ZL of the present embodiment, it is preferable that the fourth lens group G4 has two positive lens components and one negative lens component. In the fourth lens group G4, it is preferable to arrange the lens components in order of positive and negative in order from the object side with an air gap therebetween. Alternatively, it is preferable that the fourth lens group G4 has one positive lens component and one negative lens component. In the fourth lens group G4, it is preferable to arrange the lens components in order of positive and negative in order from the object side with an air gap interposed therebetween.

  The zoom lens ZL of the present embodiment has a zoom ratio of about 5-15. The zoom lens ZL according to the present embodiment is preferably about 10 to 30 mm in a state where the distance (back focus) from the image side surface of the lens component arranged closest to the image side to the image surface is the smallest. In the zoom lens ZL according to the present embodiment, the image height is preferably 5 to 12.5 mm, and more preferably 5 to 9.5 mm.

  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 zoom lens ZL of 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 CL11 formed by bonding a negative meniscus lens L11 having a convex surface toward the object side and a positive meniscus lens L12 having a concave surface toward the image side. Further, 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, a negative meniscus lens L21 having an aspheric surface on the image side and a convex surface facing the object side, a biconcave lens L22, a biconvex lens L23, and a negative meniscus lens L24 having a concave surface facing the object side are arranged as a second lens group G2, and the biconvex lens L31, the biconvex lens L32, and the biconcave lens L33 are bonded in order from the object side. A negative meniscus lens L34 having an aspheric surface on the image side and a concave surface facing the object side is disposed as a third lens group G3. In order from the object side, a biconvex lens L41 having an aspheric surface on the image side, a cemented negative lens CL41 formed by bonding a biconvex lens L42 and a biconcave lens L43, and a biconvex lens L44 are arranged. Let it be a lens group G4.

  At this time, in the third lens group G3, the curvature radius of the image side surface of the cemented negative lens CL31 of the third lens group G3 is set to r3F, and the curvature radius of the object side surface of the negative meniscus lens L34 in the third lens group G3. Where r3R is set to satisfy the following conditional expressions (1) and (2) (step S200).

r3R <0 (1)
−2.00 <(r3R + r3F) / (r3R−r3F) <1.00 (2)

  Hereinafter, each example of the present application will be described with reference to the drawings. FIG. 1 is a diagram illustrating a state of movement of each lens group in the refractive power distribution of the zoom lens ZL according to the present embodiment and the change in the focal length state from the wide-angle end state (W) to the telephoto end state (T). . 2, 4, 6, 8, 10, and 12 are cross-sectional views illustrating the configuration of the zoom lens ZL (ZL1 to ZL6) according to each example. As shown in these drawings, in each of the zoom lenses ZL1 to ZL6 according to the present embodiment, in order from the object side, the first lens group G1 having a positive refractive power and the second lens having a negative refractive power. The lens unit G2 includes a group G2, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and a filter group FL. When the focal length state changes from the wide-angle end state to the telephoto end state (that is, zooming), the first lens group G1 moves with respect to the image plane, and the distance between the first lens group G1 and the second lens group G2 Changes, the distance between the second lens group G2 and the third lens group G3 decreases, and the distance between the third lens group G3 and the fourth lens group G4 decreases. The lens group G3 and the fourth lens group G4 move to the object side, and the second lens group G2 moves. Here, the filter group FL includes a low-pass filter, an infrared cut filter, and the like. The image plane I is imaged on an imaging element (not shown) (for example, a film, a CCD, a CMOS, etc.).

  The aperture stop S is disposed closest to the object side of 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.

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. 2 is a diagram showing a configuration of the zoom lens ZL1 according to the first example of the present application. In the zoom lens ZL1 of FIG. 2, the first lens group G1 is composed of, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a concave surface facing the image side. It is composed of a cemented positive lens CL11 and a positive meniscus lens L13 having a convex surface facing the object side. The second lens group G2 has, in order from the object side, a negative meniscus lens L21 having an aspheric surface on the image side and a convex surface facing the object side, a biconcave lens L22, a biconvex lens L23, and a concave surface facing the object side. It is composed of a negative meniscus lens L24. The third lens group G3 includes, in order from the object side, a biconvex lens L31, a cemented negative lens CL31 formed by bonding the biconvex lens L32 and the biconcave lens L33, and an aspheric surface on the image side, with a concave surface facing the object side. It is composed of a negative meniscus lens L34. The fourth lens group G4 includes, in order from the object side, a biconvex lens L41 having an aspheric surface on the image side, a cemented negative lens CL41 formed by bonding the biconvex lens L42 and the biconcave lens L43, and a biconvex lens. L44.

  Table 1 below lists values of specifications of the zoom lens ZL1 according to the first example. In Table 1, f represents the focal length, FNO represents the F number, 2ω represents the angle of view, and Bf represents the back focus. Furthermore, the surface number is the order of the lens surfaces from the object side along the direction of travel of the light beam, the surface interval is the distance on the optical axis from each optical surface to the next optical surface, and the refractive index and Abbe number are each The value for the d-line (λ = 587.6 nm) is shown. The total length represents the distance on the optical axis from the first surface of the lens surface to the image plane I when focusing on infinity. 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 embodiments.

(Table 1)
Wide angle end Intermediate focal length 1 Intermediate focal length 2 Telephoto end f = 10.51 to 26.91 to 70.00 to 107.09
F.NO = 3.41 to 4.56 to 5.60 to 5.92
2ω = 80.74 to 34.10 to 13.57 to 8.93
Air conversion Bf = 15.73 to 28.33 to 39.26 to 42.73
Air equivalent total length = 89.88 to 104.35 to 125.23 to 131.28
Image height = 8.50 to 8.50 to 8.50 to 8.50

Surface number Curvature radius Surface spacing Refractive index Abbe number
1 61.1581 1.20 1.84666 23.78
2 40.0620 5.60 1.49700 81.54
3 423.5882 0.50
4 46.1934 3.35 1.67790 55.34
5 182.2832 (d5)
6 61.2018 1.20 1.80139 45.46
* 7 9.3577 4.60
8 -27.3674 0.85 1.78800 47.37
9 41.1686 0.30
10 22.0377 3.15 1.80810 22.76
11 -32.1910 0.65
12 -19.7165 0.85 1.75500 52.32
13 -407.6339 (d13)
14 0.0000 0.50 (Aperture stop S)
15 14.8924 2.60 1.60300 65.44
16 -40.4513 0.10
17 17.4716 3.45 1.49700 81.54
18 -21.2482 1.45 1.88300 40.76
19 39.7309 1.75
20 -17.0463 1.00 1.80139 45.46
* 21 -51.3354 (d21)
22 18.2360 4.00 1.61881 63.86
* 23 -34.0096 0.60
24 48.8072 3.00 1.60300 65.44
25 -12.3504 1.20 1.75500 52.32
26 13.7843 2.00
27 16.9250 2.85 1.51680 64.12
28 -87.6437 (d28)
29 0.0000 1.00 1.51680 64.12
30 0.0000 1.50
31 0.0000 1.87 1.51680 64.12
32 0.0000 0.40
33 0.0000 0.70 1.51680 64.12
34 0.0000 (Bf)

  In the first embodiment, the lens surfaces of the seventh surface, the twenty-first surface, and the twenty-third surface are formed in an aspherical shape. Table 2 below shows aspherical data, that is, vertex radius of curvature R, conic constant κ, and values of aspherical constants A4 to A10.

(Table 2)
R κ A4 A6 A8 A10
7th surface 9.3577 1.0421 -2.9241E-05 -5.0127E-07 8.6241E-09 -1.7709E-10
21st surface -51.3354 11.0000 -4.3022E-05 -9.3099E-07 1.0189E-08 -7.0307E-11
23rd surface -34.0096 11.0000 2.1147E-04 1.2036E-06 -1.5877E-08 2.1370E-10

  In the first embodiment, the axial air distance d5 between the first lens group G1 and the second lens group G2, the axial air distance d13 between the second lens group G2 and the third lens group G3, and the third lens group G3. And the on-axis air gap d21 between the fourth lens group G4 and the on-axis air gap d28 between the fourth lens group G4 and the filter group FL change during zooming. Table 3 below shows variable intervals at the respective focal lengths in the wide-angle end state, the intermediate focal length state 1, the intermediate focal length state 2, and the telephoto end state.

(Table 3)
Wide angle end Intermediate focal length 1 Intermediate focal length 2 Telephoto end
f 10.5100 26.9148 69.9996 107.0852
d5 1.3000 15.9163 32.2603 37.7051
d13 23.2000 11.5316 5.5576 2.8000
d21 2.9000 1.8152 1.3998 1.3000
d28 10.9749 23.5797 34.5074 37.9749
Bf 0.4999 0.4999 0.4999 0.5001

  Table 4 below shows values corresponding to the conditional expressions of the zoom lens ZL1 according to the first example. In Table 4, fw is the focal length of the entire zoom lens ZL system in the wide-angle end state, f1 is the focal length of the first lens group G1, f2 is the focal length of the second lens group G2, and f3 is the third. The focal length of the lens group G3, f4 is the focal length of the fourth lens group G4, r3F is the radius of curvature of the image side surface of the cemented negative lens CL31 of the third lens group G3, and r3R is in the third lens group G3. The radius of curvature of the object side surface of the negative meniscus lens L34 is shown. The description of the above symbols is the same in the following embodiments.

(Table 4)
fw = 10.5100
f1 = 67.5093
f2 = -9.7136
f3 = 30.3374
f4 = 26.7735
r3F = 39.7309
(1) r3R = -17.0463
(2) (r3R + r3F) / (r3R−r3F) = − 0.3995
(3) fw / f3 = 0.3464
(4) f1 / (− f2) = 6.9500
(5) f3 / f4 = 1.1331
(6) f1 / f3 = 2.2253

  FIG. 3 shows various aberrations of the first example with respect to the d-line (λ = 587.6 nm). 3A is an aberration diagram in the infinite focus state in the wide-angle end state (f = 10.51 mm), and FIG. 3B is infinite in the intermediate focal length state 1 (f = 26.91 mm). FIG. 3C shows various aberrations in the infinite focus state in the intermediate focal length state 2 (f = 70.00 mm), and FIG. 3D shows the various aberrations in the far focus state. These are various aberrations in the infinite focus state in the state (f = 107.09 mm). In each aberration diagram, FNO indicates an F number, Y indicates an image height, and A indicates a half field angle with respect to each image height. In the aberration diagrams showing astigmatism, the solid line shows the sagittal image plane, and the broken line shows the meridional image plane. Further, in the aberration diagrams showing the spherical aberration, the solid line shows the spherical aberration, and the broken line shows the sine condition (sine condition). The description of this aberration diagram is the same in the following examples. As is apparent from the respective aberration diagrams, in the first embodiment, it is understood that various aberrations are well corrected in each focal length state from the wide-angle end state to the telephoto end state, and excellent imaging performance is obtained.

[Second Embodiment]
FIG. 4 is a diagram showing a configuration of the zoom lens ZL2 according to the second embodiment of the present application. In the zoom lens ZL2 of FIG. 4, the first lens group G1 is composed of, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a concave surface facing the image side. It is composed of a cemented positive lens CL11 and a positive meniscus lens L13 having a convex surface facing the object side. The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having an aspheric surface on the image side and a convex surface facing the object side, a biconcave lens L22, a biconvex lens L23, and a biconcave lens L24. Yes. The third lens group G3 includes, in order from the object side, a biconvex lens L31, a cemented negative lens CL31 formed by bonding the biconvex lens L32 and the biconcave lens L33, and an aspheric surface on the image side, with a concave surface facing the object side. It is composed of a negative meniscus lens L34. The fourth lens group G4 includes, in order from the object side, a biconvex lens L41 having an aspheric surface on the image side, a cemented negative lens CL41 formed by bonding the biconvex lens L42 and the biconcave lens L43, and a biconvex lens. L44.

  Table 5 below provides values of specifications of the zoom lens ZL2 according to the second example.

(Table 5)
Wide angle end Intermediate focal length 1 Intermediate focal length 2 Telephoto end f = 10.51 to 26.88 to 70.00 to 107.09
F.NO = 3.37 to 4.55 to 5.61 to 5.94
2ω = 80.65 to 34.11 to 13.52 to 8.89
Air conversion Bf = 15.56 to 28.56 to 39.54 to 43.01
Air equivalent total length = 89.97 to 102.56 to 122.53 to 128.22
Image height = 8.50 to 8.50 to 8.50 to 8.50

Surface number Curvature radius Surface spacing Refractive index Abbe number
1 57.8992 1.20 1.84666 23.78
2 37.8485 5.40 1.49700 81.54
3 455.0569 0.50
4 45.1853 3.21 1.67790 55.34
5 200.0894 (d5)
6 76.0070 1.20 1.80139 45.45
* 7 9.7908 4.58
8 -28.4260 0.85 1.78800 47.37
9 36.7782 0.30
10 21.7223 3.17 1.80810 22.76
11 -30.7063 0.61
12 -19.7864 0.85 1.75500 52.32
13 946.9644 (d13)
14 0.0000 0.50 (Aperture stop S)
15 15.3993 2.61 1.60300 65.44
16 -37.6383 0.10
17 19.0098 3.49 1.49700 81.54
18 -19.0508 1.50 1.88300 40.76
19 47.4940 1.62
20 -16.0939 1.00 1.80139 45.45
* 21 -37.0133 (d21)
22 18.5418 4.00 1.61881 63.85
* 23 -28.5379 0.86
24 67.2548 3.00 1.60300 65.44
25 -13.3315 1.20 1.75500 52.32
26 13.0827 1.71
27 16.2368 3.00 1.51680 64.10
28 -110.0854 (d28)
29 0.0000 1.00 1.51680 64.12
30 0.0000 1.50 1.00000
31 0.0000 1.87 1.51680 64.12
32 0.0000 0.40 1.00000
33 0.0000 0.70 1.51680 64.12
34 0.0000 (Bf)

  In the second embodiment, the lens surfaces of the seventh surface, the 21st surface, and the 23rd surface are formed in an aspherical shape. Table 6 below shows the aspheric data, that is, the vertex curvature radius R, the conic constant κ, and the values of the aspheric constants A4 to A10.

(Table 6)
R κ A4 A6 A8 A10
7th surface 9.7908 1.1109 -3.1862E-05 -5.4887E-07 9.3504E-09 -1.8962E-10
21st surface -37.0133 11.0000 -2.5730E-05 -7.9160E-07 9.1322E-09 -5.5758E-11
23rd surface -28.5379 11.0000 2.2123E-04 1.2734E-06 -1.4347E-08 2.5712E-10

  In the second embodiment, the axial air distance d5 between the first lens group G1 and the second lens group G2, the axial air distance d13 between the second lens group G2 and the third lens group G3, and the third lens group G3. And the on-axis air gap d21 between the fourth lens group G4 and the on-axis air gap d28 between the fourth lens group G4 and the filter group FL change during zooming. Table 7 below shows variable intervals at the respective focal lengths in the wide-angle end state, the intermediate focal length state 1, the intermediate focal length state 2, and the telephoto end state.

(Table 7)
Wide angle end Intermediate focal length 1 Intermediate focal length 2 Telephoto end
f 10.5100 26.8793 69.9997 107.0895
d5 1.3000 14.1157 29.5282 34.6555
d13 23.2000 11.4527 5.5687 2.8000
d21 3.3465 1.9639 1.4352 1.3000
d28 10.8061 23.8111 34.7874 38.2526
Bf 0.5000 0.4999 0.4999 0.4998

  Table 8 below shows values corresponding to the conditional expressions of the zoom lens ZL2 according to the second example.

(Table 8)
fw = 10.5100
f1 = 63.3539
f2 = -9.5359
f3 = 30.4795
f4 = 27.6448
r3F = 47.4940
(1) r3R = -16.0939
(2) (r3R + r3F) / (r3R-r3F) =-0.4938
(3) fw / f3 = 0.3448
(4) f1 / (− f2) = 6.6437
(5) f3 / f4 = 1.1025
(6) f1 / f3 = 2.0786

  FIG. 5 shows various aberration diagrams of the second example with respect to the d-line (λ = 587.6 nm). That is, FIG. 5A is an aberration diagram in the infinite focus state in the wide-angle end state (f = 10.51 mm), and FIG. 5B is infinite in the intermediate focal length state 1 (f = 26.88 mm). FIG. 5C shows various aberrations in the infinite focus state in the intermediate focal length state 2 (f = 70.00 mm), and FIG. 5D shows the various aberrations in the far focus state. These are various aberrations in the infinite focus state in the state (f = 107.09 mm). As is apparent from the respective aberration diagrams, in the second example, it is understood that various aberrations are favorably corrected in each focal length state from the wide-angle end state to the telephoto end state, and excellent imaging performance is obtained.

[Third embodiment]
FIG. 6 is a diagram showing a configuration of a zoom lens ZL3 according to the third example of the present application. In the zoom lens ZL3 of FIG. 6, the first lens group G1 includes, in order from the object side, a cemented positive lens CL21 formed by bonding a negative meniscus lens L11 having a convex surface facing the object side and a biconvex lens L12, and an object It is composed of a positive meniscus lens L13 having a convex surface facing the side. The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having an aspheric surface on the image side and a convex surface facing the object side, a biconcave lens L22, a biconvex lens L23, and a biconcave lens L24. Yes. The third lens group G3 includes, in order from the object side, a biconvex lens L31, a cemented negative lens CL31 formed by bonding the biconvex lens L32 and the biconcave lens L33, and an aspheric surface on the image side, with a concave surface facing the object side. It is composed of a negative meniscus lens L34. The fourth lens group G4 includes, in order from the object side, a biconvex lens L41 having an aspheric image-side surface, a cemented negative lens CL41 formed by bonding the biconvex lens L42 and the biconcave lens L43, and the image side. It is composed of a positive meniscus lens L44 having a convex surface.

  Table 9 below provides values of specifications of the zoom lens ZL3 according to the third example.

(Table 9)
Wide angle end Intermediate focal length 1 Intermediate focal length 2 Telephoto end
f = 10.51 to 16.50 to 41.00 to 107.09
F.NO = 3.07 to 3.53 to 4.63 to 5.83
2ω = 80.82 to 53.18 to 22.58 to 8.89
Air conversion Bf = 20.63 to 26.70 to 39.83 to 53.07
Total air equivalent = 83.79 to 88.67 to 108.77 to 128.78
Image height = 8.50 to 8.50 to 8.50 to 8.50

Surface number Curvature radius Surface spacing Refractive index Abbe number
1 60.9480 1.20 1.92286 20.88
2 43.6565 4.30 1.49700 81.54
3 -386.1029 0.50
4 43.7100 2.65 1.64000 60.08
5 112.1795 (d5)
6 54885.3920 1.00 1.80139 45.45
* 7 10.5338 3.58
8 -76.2868 0.85 1.81600 46.62
9 20.0765 0.10
10 17.8807 3.65 1.80810 22.76
11 -26.7256 0.45
12 -23.1129 0.85 1.77250 49.60
13 55.6994 (d13)
14 0.0000 0.50 (Aperture stop S)
15 16.2624 2.45 1.60311 60.64
16 -31.8849 0.10
17 30.4987 2.55 1.49700 81.54
18 -17.5829 0.80 1.88300 40.76
19 80.4259 1.80
20 -12.1903 1.00 1.80610 40.73
* 21 -20.5989 (d21)
22 18.0823 3.50 1.61881 63.85
* 23 -29.2315 0.50
24 27.0281 3.00 1.60300 65.44
25 -18.4995 0.90 1.77250 49.60
26 15.2175 1.30
27 -155.5751 2.00 1.51633 64.14
28 -18.8809 (d28)
29 0.0000 1.00 1.51680 64.12
30 0.0000 1.50
31 0.0000 1.87 1.51680 64.12
32 0.0000 0.40
33 0.0000 0.70 1.51680 64.12
34 0.0000 (Bf)

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

(Table 10)
R κ A4 A6 A8 A10
7th surface 10.5338 1.1144 -4.7460E-05 -5.7358E-07 4.5188E-09 -1.2043E-10
Surface 21 -20.5989 -2.1097 -1.1711E-04 -7.4538E-07 9.1645E-09 -8.6943E-11
Side 23 -29.2315 -1.4131 1.4997E-04 3.4591E-07 -1.3285E-08 1.1071E-10

  In the third embodiment, the axial air distance d5 between the first lens group G1 and the second lens group G2, the axial air distance d13 between the second lens group G2 and the third lens group G3, and the third lens group G3. And the on-axis air gap d21 between the fourth lens group G4 and the on-axis air gap d28 between the fourth lens group G4 and the filter group FL change during zooming. Table 11 below shows variable intervals at the respective focal lengths in the wide-angle end state, the intermediate focal length state 1, the intermediate focal length state 2, and the telephoto end state.

(Table 11)
Wide angle end Intermediate focal length 1 Intermediate focal length 2 Telephoto end
f 10.5100 16.5000 41.0000 107.0901
d5 1.3000 7.0203 21.7084 34.3815
d13 18.3381 12.3410 5.9452 1.3000
d21 4.0000 3.0748 1.7579 0.5000
d28 15.8766 21.9466 35.0784 48.3185
Bf 0.5000 0.5000 0.5000 0.5001

  Table 12 below shows values corresponding to the conditional expressions of the zoom lens ZL3 according to the third example.

(Table 12)
fw = 10.5100
f1 = 64.0667
f2 = -9.0945
f3 = 41.2846
f4 = 21.9579
r3F = 80.4259
(1) r3R = -12.1903
(2) (r3R + r3F) / (r3R−r3F) = − 0.7368
(3) fw / f3 = 0.546
(4) f1 / (− f2) = 7.0446
(5) f3 / f4 = 1.8802
(6) f1 / f3 = 1.5518

  FIG. 7 shows various aberration diagrams of the third example with respect to the d-line (λ = 587.6 nm). 7A is an aberration diagram in the infinitely focused state in the wide-angle end state (f = 10.51 mm), and FIG. 7B is infinite in the intermediate focal length state 1 (f = 16.50 mm). FIG. 7C shows various aberrations in the infinite focus state in the intermediate focal length state 2 (f = 41.00 mm), and FIG. 7D shows the various aberrations in the far focus state. These are various aberrations in the infinite focus state in the state (f = 107.09 mm). As is apparent from the respective aberration diagrams, in the third example, it is understood that various aberrations are favorably corrected in each focal length state from the wide-angle end state to the telephoto end state, and excellent imaging performance is obtained.

[Fourth embodiment]
FIG. 8 is a diagram showing a configuration of a zoom lens ZL4 according to the fourth example of the present application. In the zoom lens ZL3 of FIG. 8, the first lens group G1 includes, in order from the object side, a cemented positive lens CL11 formed by bonding a negative meniscus lens L11 having a convex surface facing the object side and a biconvex lens L12, and an object It is composed of a positive meniscus lens L13 having a convex surface facing the side. The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having an aspheric surface on the object side and a convex surface facing the object side, a biconcave lens L22, a biconvex lens L23, and a biconcave lens L24. Yes. The third lens group G3 includes, in order from the object side, a biconvex lens L31, a cemented negative lens CL31 formed by bonding the biconvex lens L32 and the biconcave lens L33, and an aspheric surface on the image side, with a concave surface facing the object side. It is composed of a negative meniscus lens L34. The fourth lens group G4 includes, in order from the object side, a biconvex lens L41 having an aspheric image-side surface, a cemented negative lens CL41 formed by bonding the biconvex lens L42 and the biconcave lens L43, and the image side. It is composed of a positive meniscus lens L44 having a convex surface.

  Table 13 below provides values of specifications of the zoom lens ZL4 according to the fourth example.

(Table 13)
Wide angle end Intermediate focal length 1 Intermediate focal length 2 Telephoto end f = 10.51 to 26.50 to 70.00 to 107.09
F.NO = 3.09 to 4.29 to 5.46 to 5.91
2ω = 80.75 to 34.44 to 13.42 to 8.84
Air conversion Bf = 19.57 to 33.96 to 46.90 to 51.53
Total air equivalent = 83.02 to 96.82 to 121.42 to 129.28
Image height = 8.50 to 8.50 to 8.50 to 8.50

Surface number Curvature radius Surface spacing Refractive index Abbe number
1 62.9234 1.20 1.84666 23.78
2 41.4487 4.30 1.49700 81.54
3 -1095.0606 0.50
4 50.3782 2.65 1.64000 60.08
5 210.9338 (d5)
* 6 250.0000 0.15 1.55389 38.09
7 220.8785 1.20 1.81600 46.62
8 10.5756 3.58
9 -42.1978 0.85 1.81600 46.62
10 19.2084 0.10
11 16.8043 3.45 1.84666 23.78
12 -32.5573 0.30
13 -32.6346 0.85 1.75500 52.32
14 47.6411 (d14)
15 0.0000 0.50 (Aperture stop S)
16 16.3033 2.45 1.60311 60.64
17 -31.1607 0.10
18 33.1851 2.45 1.49700 81.54
19 -15.5536 0.80 1.88300 40.76
20 325.4851 1.55
21 -14.2228 1.00 1.80139 45.45
* 22 -30.6056 (d22)
23 16.2509 3.50 1.61881 63.85
* 24 -36.1517 0.50
25 21.4327 3.00 1.60300 65.44
26 -20.2471 0.90 1.77250 49.60
27 13.6451 1.30
28 -169.7512 2.00 1.48749 70.23
29 -20.6001 (d29)
30 0.0000 1.00 1.51680 64.12
31 0.0000 1.50
32 0.0000 1.87 1.51680 64.12
33 0.0000 0.40
34 0.0000 0.70 1.51680 64.12
35 0.0000 (Bf)

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

(Table 14)
R κ A4 A6 A8 A10
6th surface 11.7888 11.0000 1.3146E-05 -1.0696E-07 1.6163E-10 1.3273E-14
No. 22 -30.6056 -0.5287 -9.7684E-05 -7.5194E-07 1.0715E-08 -8.3651E-11
24th surface -36.1517 11.0000 2.0568E-04 4.2479E-07 -1.2045E-08 1.0677E-10

  In the fourth embodiment, the axial air distance d5 between the first lens group G1 and the second lens group G2, the axial air distance d14 between the second lens group G2 and the third lens group G3, and the third lens group G3. And the on-axis air gap d22 between the fourth lens group G4 and the on-axis air gap d29 between the fourth lens group G4 and the filter group FL change during zooming. Table 15 below shows variable intervals at the respective focal lengths in the wide-angle end state, the intermediate focal length state 1, the intermediate focal length state 2, and the telephoto end state.

(Table 15)
Wide angle end Intermediate focal length 1 Intermediate focal length 2 Telephoto end
f 10.5100 26.5022 69.9999 107.0898
d5 1.3000 12.8162 30.2193 35.9709
d14 18.4655 8.0479 3.3238 1.3000
d22 4.5056 2.8181 1.7954 1.3000
d29 14.8166 29.2033 42.1507 46.7791
Bf 0.5000 0.5000 0.4999 0.4999

  Table 16 below shows values corresponding to the conditional expressions of the zoom lens ZL4 according to the fourth example.

(Table 16)
fw = 10.5100
f1 = 66.4840
f2 = -9.3184
f3 = 40.7867
f4 = 21.99953
r3F = 325.4851
(1) r3R = -14.2228
(2) (r3R + r3F) / (r3R-r3F) =-0.9163
(3) fw / f3 = 0.2577
(4) f1 / (− f2) = 7.1347
(5) f3 / f4 = 1.8544
(6) f1 / f3 = 1.6300

  FIG. 9 shows various aberration diagrams of the fourth example with respect to the d-line (λ = 587.6 nm). 9A is an aberration diagram in the infinite focus state in the wide-angle end state (f = 10.51 mm), and FIG. 9B is infinite in the intermediate focal length state 1 (f = 26.50 mm). FIG. 9C shows various aberrations in the infinite focus state in the intermediate focal length state 2 (f = 70.00 mm), and FIG. 9D shows the various aberrations in the far focus state. These are various aberrations in the infinite focus state in the state (f = 107.09 mm). As is apparent from the respective aberration diagrams, in the fourth example, it is understood that various aberrations are favorably corrected in each focal length state from the wide-angle end state to the telephoto end state, and excellent imaging performance is obtained.

[Fifth embodiment]
FIG. 10 is a diagram showing a configuration of a zoom lens ZL5 according to Example 5 of the present application. In the zoom lens ZL5 of FIG. 10, the first lens group G1 includes, in order from the object side, a cemented positive lens CL11 formed by bonding a negative meniscus lens L11 having a convex surface facing the object side and a biconvex lens L12, and an object It is composed of a positive meniscus lens L13 having a convex surface facing the side. The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having an aspheric surface on the image side and a convex surface facing the object side, a biconcave lens L22, a biconvex lens L23, and a biconcave lens L24. Yes. The third lens group G3 includes, in order from the object side, a biconvex lens L31, a cemented negative lens CL31 formed by bonding the biconvex lens L32 and the biconcave lens L33, an aspheric surface on the image side, and a concave surface on the object side. It is composed of a negative meniscus lens L34 directed to it. The fourth lens group G4 includes, in order from the object side, a biconvex lens L41 having an aspheric image-side surface, a cemented negative lens CL41 formed by bonding the biconvex lens L42 and the biconcave lens L43, and the image side. It is composed of a positive meniscus lens L44 having a convex surface.

  Table 17 below provides values of specifications of the zoom lens ZL5 according to the fifth example.

(Table 17)
Wide angle end Intermediate focal length 1 Intermediate focal length 2 Telephoto end f = 10.51 to 42.67 to 74.88 to 107.09
F.NO = 3.51 to 5.14 to 5.59 to 5.87
2ω = 80.87 to 21.92 to 12.69 to 8.92
Air conversion Bf = 21.43 to 40.89 to 45.83 to 48.73
Total length in terms of air = 89.16 to 113.36 to 124.00 to 128.55
Image height = 8.50 to 8.50 to 8.50 to 8.50

Surface number Curvature radius Surface spacing Refractive index Abbe number
1 60.6424 1.20 1.92286 20.88
2 44.2044 4.32 1.49700 81.54
3 -515.1939 0.50
4 42.0272 2.89 1.64000 60.08
5 95.3411 (d5)
6 485.6443 1.00 1.80139 45.45
* 7 9.9481 4.00
8 -51.2325 0.85 1.81600 46.62
9 26.3336 0.10
10 19.8742 3.40 1.80810 22.76
11 -31.3904 0.45
12 -26.2951 0.85 1.77250 49.60
13 138.0483 (d13)
14 0.0000 0.50 (Aperture stop S)
15 16.4056 2.27 1.60311 60.64
16 -39.0374 0.66
17 27.6953 3.50 1.49700 81.54
18 -16.8310 0.80 1.88300 40.76
19 191.9955 1.04
20 -14.2816 1.35 1.80610 40.73
* 21 -32.6678 (d21)
22 23.6409 3.19 1.61881 63.85
* 23 -27.5142 0.50
24 34.9735 2.69 1.60300 65.44
25 -16.7294 0.80 1.77250 49.60
26 23.8867 1.24
27 -49.9928 1.84 1.51633 64.14
28 -18.8976 (d28)
29 0.0000 1.00 1.51680 64.12
30 0.0000 1.50
31 0.0000 1.87 1.51680 64.12
32 0.0000 0.40
33 0.0000 0.70 1.51680 64.12
34 0.0000 (Bf)

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

(Table 18)
R κ A4 A6 A8 A10
6th surface 9.9481 0.0827 7.8703E-05 1.0563E-07 4.7955E-09 1.4870E-12
Side 21 -32.6678 -9.0000 -1.1582E-04 -6.8174E-07 1.3450E-08 -1.5683E-10
23rd surface -27.5142 -3.9670 1.1423E-04 6.9036E-07 -1.4970E-08 1.5634E-10

  In the fifth embodiment, the axial air distance d5 between the first lens group G1 and the second lens group G2, the axial air distance d13 between the second lens group G2 and the third lens group G3, and the third lens group G3. And the on-axis air gap d21 between the fourth lens group G4 and the on-axis air gap d28 between the fourth lens group G4 and the filter group FL change during zooming. Table 19 below shows variable intervals at the respective focal lengths in the wide-angle end state, the intermediate focal length state 1, the intermediate focal length state 2, and the telephoto end state.

(Table 19)
Wide angle end Intermediate focal length 1 Intermediate focal length 2 Telephoto end
f 10.5100 42.6701 74.8800 107.0900
d5 1.2000 23.2905 32.6418 36.9877
d13 21.9234 6.5711 3.4356 1.1000
d21 4.6689 2.6654 2.1652 1.7929
d28 16.6828 36.1442 41.0739 43.9859
Bf 0.4983 0.4963 0.4987 0.4946

  Table 20 below shows values corresponding to the conditional expressions of the zoom lens ZL5 according to Example 5.

(Table 20)
fw = 10.5100
f1 = 66.0690
f2 = -9.8826
f3 = 39.7119
f4 = 24.0113
r3F = 191.9955
(1) r3R = -14.2816
(2) (r3R + r3F) / (r3R−r3F) = − 0.8615
(3) fw / f3 = 0.2647
(4) f1 / (− f2) = 6.6854
(5) f3 / f4 = 1.6539
(6) f1 / f3 = 1.6637

  FIG. 11 shows various aberration diagrams of the fifth example with respect to the d-line (λ = 587.6 nm). That is, FIG. 11A is an aberration diagram in the infinite focus state in the wide-angle end state (f = 10.51 mm), and FIG. 11B is infinite in the intermediate focal length state 1 (f = 42.67 mm). FIG. 11C shows various aberrations in the infinite focus state in the intermediate focal length state 2 (f = 74.88 mm), and FIG. 11D shows the various aberrations in the far focus state. These are various aberrations in the infinite focus state in the state (f = 107.09 mm). As is apparent from each aberration diagram, in the fifth example, it is understood that various aberrations are well corrected in each focal length state from the wide-angle end state to the telephoto end state, and excellent imaging performance is obtained.

[Sixth embodiment]
FIG. 12 is a diagram showing a configuration of a zoom lens ZL6 according to Example 6 of the present application. In the zoom lens ZL6 of FIG. 12, the first lens group G1 is composed of, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a concave surface facing the image side. It is composed of a cemented positive lens CL11 and a positive meniscus lens L13 having a convex surface facing the object side. The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having an aspheric surface on the image side and a convex surface facing the object side, a biconcave lens L22, a biconvex lens L23, and a biconcave lens L24. Yes. The third lens group G3 includes, in order from the object side, a biconvex lens L31, a cemented negative lens CL31 formed by bonding the biconvex lens L32 and the biconcave lens L33, and an aspheric surface on the image side, with a concave surface facing the object side. It is composed of a negative meniscus lens L34. The fourth lens group G4 includes, in order from the object side, a biconvex lens L41 having an aspheric surface on the image side, and a negative meniscus L42 having a convex surface facing the object side and a biconvex lens L43. It consists of a cemented negative lens CL41.

  Table 21 below provides values of specifications of the zoom lens ZL6 according to Example 6.

(Table 21)
Wide angle end Intermediate focal length 1 Intermediate focal length 2 Telephoto end f = 10.46 to 16.10 to 37.76 to 109.66
F.NO = 3.05 to 3.50 to 4.82 to 5.99
2ω = 81.15 to 55.01 to 24.91 to 8.76
Air conversion Bf = 21.44 to 27.29 to 43.33 to 56.58
Air equivalent total length = 82.30 to 86.37 to 104.31 to 127.78
Image height = 8.50 to 8.50 to 8.50 to 8.50

Surface number Curvature radius Surface spacing Refractive index Abbe number
1 52.4618 0.82 1.92286 20.88
2 39.5464 4.73 1.49700 81.54
3 5279.8040 0.50
4 39.0489 2.79 1.60300 65.44
5 101.4457 (d5)
6 242.8497 0.80 1.80139 45.45
* 7 9.6078 3.97
8 -53.0915 0.80 1.81600 46.62
9 27.1207 0.10
10 19.2442 3.40 1.80810 22.76
11 -28.4265 0.45
12 -21.3643 0.80 1.75500 52.32
13 74.4746 (d13)
14 0.0000 0.10 (Aperture stop S)
15 18.3624 2.37 1.60300 65.44
16 -34.3973 0.10
17 19.6723 3.20 1.51633 64.14
18 -21.6943 0.80 1.85026 32.34
19 618.5341 1.93
20 -13.1758 1.00 1.80139 45.45
* 21 -60.8070 (d21)
22 22.8062 3.50 1.61881 63.85
* 23 -22.1250 0.50
24 225.5495 0.80 1.77250 49.60
25 10.7683 2.93 1.60300 65.44
26 -181.8838 (d26)
27 0.0000 1.00 1.51680 64.12
28 0.0000 1.50
29 0.0000 1.87 1.51680 64.12
30 0.0000 0.40
31 0.0000 0.70 1.51680 64.12
32 0.0000 (Bf)

  In the sixth embodiment, the lens surfaces of the seventh surface, the twenty-first surface, and the twenty-third surface are formed in an aspherical shape. Table 22 below shows the data of aspheric surfaces, that is, the values of the vertex curvature radius R, the conic constant κ, and the aspheric constants A4 to A10.

(Table 22)
R κ A4 A6 A8 A10
6th surface 9.6078 0.9084 -2.8248E-05 -4.9541E-07 4.7856E-09 -1.1480E-10
Side 21 -60.8070 7.5867 -1.2929E-04 -1.1174E-06 1.2284E-08 -8.8483E-11
23rd surface -22.1250 -5.6671 1.1409E-04 1.3392E-06 -1.5434E-08 1.2476E-10

  In the sixth example, the axial air distance d5 between the first lens group G1 and the second lens group G2, the axial air distance d13 between the second lens group G2 and the third lens group G3, and the third lens group G3. The axial air distance d21 between the fourth lens group G4 and the axial air distance d26 between the fourth lens group G4 and the filter group FL changes during zooming. Table 23 below shows variable intervals at the respective focal lengths in the wide-angle end state, the intermediate focal length state 1, the intermediate focal length state 2, and the telephoto end state.

(Table 23)
Wide angle end Intermediate focal length 1 Intermediate focal length 2 Telephoto end
f 10.4606 16.1003 37.7622 109.6618
d5 1.1999 6.2049 16.2467 32.2485
d13 19.2587 13.2288 6.1018 1.1000
d21 4.0000 3.2510 2.2402 1.4553
d26 16.6908 22.5374 38.5747 51.8268
Bf 0.4999 0.4961 0.4993 0.5025

  Table 24 below shows values corresponding to the conditional expressions of the zoom lens ZL6 according to the sixth example.

(Table 24)
fw = 10.4606
f1 = 61.6382
f2 = -9.0259
f3 = 33.0321
f4 = 22.0798
r3F = 618.5341
(1) r3R = -13.1758
(2) (r3R + r3F) / (r3R-r3F) =-0.9583
(3) fw / f3 = 0.3167
(4) f1 / (− f2) = 6.8291
(5) f3 / f4 = 1.4960
(6) f1 / f3 = 1.8660

  FIG. 13 shows various aberration diagrams of the sixth example for the d-line (λ = 587.6 nm). 13A is an aberration diagram in the infinite focus state in the wide-angle end state (f = 10.46 mm), and FIG. 13B is infinite in the intermediate focal length state 1 (f = 16.10 mm). FIG. 13C shows various aberrations in the infinite focus state in the intermediate focal length state 2 (f = 37.76 mm), and FIG. 13D shows the various aberrations in the far focus state. These are various aberrations in the infinite focus state in the state (f = 109.66 mm). As is apparent from each aberration diagram, in the sixth example, it is understood that various aberrations are well corrected in each focal length state from the wide-angle end state to the telephoto end state, and excellent imaging performance is obtained.

ZL (ZL1 to ZL6) Zoom lens G1 First lens group G2 Second lens group G3 Third lens group G4 Fourth lens group S Aperture stop 1 Digital single-lens reflex camera (optical apparatus)

Claims (16)

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 a positive refractive power,
The third lens group includes, in order from the object side, a first positive lens, a cemented lens of a second positive lens and a negative meniscus lens, and a negative lens.
When the radius of curvature of the image side surface of the cemented lens of the third lens group is r3F, and the radius of curvature of the object side surface of the negative meniscus lens in the third lens group is r3R, the following formula r3R <0
−2.00 <(r3R + r3F) / (r3R−r3F) <1.00
Zoom lens that satisfies the above conditions.   The first positive lens in the third lens group is disposed with a convex surface facing the object side, and the cemented lens is configured such that the second positive lens faces the convex surface toward the object side and the negative lens is concave toward the image side. The zoom lens according to claim 1, wherein the negative meniscus lens is disposed with a convex surface facing the image side. When the focal length of the entire lens system in the wide-angle end state is fw and the focal length of the third lens group is f3, the following expression 0.10 <fw / f3 <0.50
The zoom lens according to claim 1, wherein the zoom lens satisfies the following condition.   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 changes, and the distance between the second lens group and the third lens group changes, 4. The device according to claim 1, wherein at least the first lens group and the fourth lens group are moved toward the object side so that an interval between the third lens group and the fourth lens group changes. The zoom lens according to one item.   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 distance between the second lens group and the third lens group decreases. The zoom lens according to any one of claims 1 to 4, wherein an interval between the third lens group and the fourth lens group is reduced. When the focal length of the first lens group is f1 and the focal length of the second lens group is f2, the following expression 6.00 <f1 / (− f2) <7.80
The zoom lens according to claim 1, wherein the zoom lens satisfies the following condition.   The zoom lens according to claim 1, further comprising an aperture stop between the second lens group and the third lens group.   The zoom lens according to claim 1, wherein the cemented lens in the third lens group has a negative refractive power.   The zoom lens according to claim 1, further comprising at least one aspheric lens in the third lens group.   10. The zoom lens according to claim 1, wherein an image side lens surface of the negative meniscus lens located on the image side of the cemented lens of the third lens group is formed in an aspherical shape. When the focal length of the third lens group is f3 and the focal length of the fourth lens group is f4, the following expression 0.15 <f3 / f4 <2.75
The zoom lens according to claim 1, wherein the zoom lens satisfies the following condition. When the focal length of the first lens group is f1, and the focal length of the third lens group is f3, the following expression 0.85 <f1 / f3 <2.74
The zoom lens according to claim 1, wherein the zoom lens satisfies the following condition.   The zoom lens according to any one of claims 1 to 12, wherein focusing on a short-distance object is performed by moving at least a part of the second lens group along an optical axis.   The zoom lens according to claim 1, wherein at least a part of the third lens group moves so as to have a component in a direction substantially perpendicular to the optical axis.   The optical apparatus provided with the zoom lens according to any one of claims 1 to 14, wherein an image of an object is formed on a predetermined image plane. 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 positive refractive power A zoom lens manufacturing method comprising:
In order from the object side, a first positive lens, a cemented lens of a second positive lens and a negative lens, and a negative meniscus lens are arranged in the third lens group,
When the third lens group has a radius of curvature on the image side of the cemented lens of the third lens group as r3F and a radius of curvature on the object side of the negative meniscus lens in the third lens group as r3R, r3R <0
−2.00 <(r3R + r3F) / (r3R−r3F) <1.00
The zoom lens manufacturing method is arranged so as to satisfy the above condition.

Images