JP2012068303A - Photographic lens, optical equipment including photographic lens, and method for manufacturing photographic lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photographic lens having excellent optical performance, optical equipment including the photographic lens, and a method for manufacturing the photographic lens.SOLUTION: A photographic lens SL mounted on a single lens reflex camera 1, etc. comprises: a front group which is arranged nearest to an object side and has negative refractive power; and a rear group which is arranged nearer to an image side than the front group, has negative refractive power, and moves so that at least a part has a component of a substantially vertical direction to an optical axis. The rear group is constituted of a first negative lens component G3a, a second negative lens component G3b and a positive lens component G3c. The second negative lens component G3b is arranged between the first negative lens component G3a and the positive lens component G3c. A lens surface of the first negative lens component G3a on the second negative lens component G3b side is formed to turn a recessed surface to the second negative lens component G3b. The second negative lens component G3b has a negative meniscus lens shape so that the recessed surface is turned to the first negative lens component G3a. At least one surface of the lens components has an aspherical surface.

Description

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

  2. Description of the Related Art Conventionally, a zoom lens having an anti-vibration function has been proposed that is a zoom lens suitable for wide-angle shooting since the first lens group is a negative lens group (see, for example, Patent Document 1). In this zoom lens, the third lens group having a negative refractive power is used as an anti-vibration lens group, thereby obtaining good anti-vibration performance.

Japanese Patent Laid-Open No. 7-152002

  However, there is a demand for a photographing lens that can perform wide-angle photographing with higher optical performance than a conventional zoom lens. In particular, higher optical performance is required for a wide-aperture wide-angle zoom lens.

  The present invention has been made in view of such a problem, and an object thereof is to provide a photographic lens capable of obtaining high optical performance, an optical apparatus including the photographic lens, and a method for manufacturing the photographic lens.

  In order to solve the above problems, a photographic lens according to the present invention is arranged closest to the object side and has a negative refractive power, and is arranged closer to the image side than the front group and has a negative refractive power, And a rear group that moves so that at least a part has a component substantially perpendicular to the optical axis. The rear group includes a first negative lens component having a negative refractive power, a second negative lens component having a negative refractive power, and a positive lens component having a positive refractive power. The second negative lens component is disposed between the first negative lens component and the positive lens component, and the lens surface on the second negative lens component side of the first negative lens component is relative to the second negative lens component. The second negative lens component has a negative meniscus lens shape with the concave surface facing the first negative lens component, and the first negative lens component, the second negative lens component, At least one surface of the positive lens components has an aspheric surface.

  Further, such a photographing lens has an aperture stop in the vicinity of the rear group, and the rear group is arranged in order of the first negative lens component, the second negative lens component, and the positive lens component in order from the aperture stop side. It is preferable that

  In such a photographic lens, the positive lens component is preferably a biconvex shape.

  In such a photographing lens, it is preferable that at least one of the first negative lens component, the second negative lens component, and the positive lens component is a cemented lens in which a negative lens and a positive lens are cemented.

  In such a photographing lens, it is preferable that the cemented surface of the cemented lens has a concave surface with respect to the aperture stop.

  In addition, such a photographing lens is disposed between the first lens group as the front group and the third lens group as the rear group, and includes a second lens group having positive refractive power, and a third lens group. And a fourth lens group that is disposed on the image side and has a positive refractive power. 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. Preferably, 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 changes.

  In this case, 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 decreases, the distance between the second lens group and the third lens group increases, It is preferable that the distance between the third lens group and the fourth lens group is reduced.

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

  In addition, a method for manufacturing a photographic lens according to the present invention is a method for manufacturing a photographic lens having a front group having negative refracting power and a rear group having negative refracting power, the front group closest to the object side. A first negative lens component having a negative refractive power, a negative meniscus second negative lens component having a negative refractive power, and a positive refractive power. A positive lens component having a second negative lens component located between the first negative lens component and the positive lens component and an air lens between the first negative lens component and the second negative lens component. Arranged in the rear group so that the shape is a biconvex shape, and has an aspheric surface on at least one of the first negative lens component, the second negative lens component, and the positive lens component, and at least a part of the rear group , And so as to move so as to have a component substantially perpendicular to the optical axis.

  When the photographing lens according to the present invention, the optical apparatus including the photographing lens, and the manufacturing method of the photographing lens are configured as described above, a large-diameter photographing lens capable of wide-angle photographing can be obtained with higher optical performance. Can do.

It is a lens sectional view showing the composition of the photographing lens concerning the 1st example. FIG. 4A is a diagram illustrating various aberrations of the first embodiment, in which FIG. 4A is an aberration diagram in an infinitely focused state in a wide-angle end state, and FIG. It is a lateral aberration diagram after. FIG. 5A is a diagram illustrating various aberrations of the first embodiment, in which FIG. 9A is an aberration diagram in an infinite focus state in an intermediate focal length state, and FIG. It is a lateral aberration diagram after vibration correction. FIG. 4A is a diagram illustrating various aberrations of the first embodiment, in which FIG. 4A is an aberration diagram in an infinitely focused state in a telephoto end state, and FIG. 4B is an image stabilization correction in an infinitely focused state in a telephoto end state. It is a lateral aberration diagram after. It is a lens sectional view showing the composition of the photographing lens concerning the 2nd example. FIG. 4A is a diagram illustrating various aberrations of the second embodiment, in which FIG. 3A is an aberration diagram in an infinitely focused state in a wide-angle end state, and FIG. It is a lateral aberration diagram after. FIG. 4A is a diagram illustrating various aberrations of the second embodiment, in which FIG. 4A is an aberration diagram in an infinite focus state in an intermediate focal length state, and FIG. It is a lateral aberration diagram after vibration correction. FIG. 5A is a diagram illustrating various aberrations of the second embodiment, in which FIG. 9A is an aberration diagram in an infinite focus state in a telephoto end state, and FIG. 9B is an image stabilization correction in an infinite focus state in a telephoto end state. It is a lateral aberration diagram after. It is a lens sectional view showing the composition of the photographing lens concerning the 3rd example. FIG. 6A is a diagram illustrating various aberrations of the third embodiment, in which FIG. 9A is an aberration diagram in an infinitely focused state in a wide-angle end state, and FIG. It is a lateral aberration diagram after. FIG. 6A is a diagram illustrating various aberrations of the third embodiment, in which FIG. 9A is an aberration diagram in an infinite focus state in an intermediate focal length state, and FIG. It is a lateral aberration diagram after vibration correction. FIG. 6A is a diagram illustrating various aberrations of the third embodiment, in which FIG. 9A is an aberration diagram in an infinite focus state in a telephoto end state, and FIG. 9B is an image stabilization correction in an infinite focus state in a telephoto end state. It is a lateral aberration diagram after. It is a lens sectional view showing the composition of the photographic lens concerning the 4th example. FIG. 6A is a diagram illustrating various aberrations of the fourth example, where FIG. 5A is an aberration diagram in an infinitely focused state at a wide-angle end state, and FIG. It is a lateral aberration diagram after. FIG. 4A is a diagram illustrating various aberrations of the fourth example, in which FIG. 4A is an aberration diagram in an infinite focus state in an intermediate focal length state, and FIG. It is a lateral aberration diagram after vibration correction. FIG. 4A is a diagram illustrating various aberrations of the fourth example, where FIG. 3A is an aberration diagram in an infinitely focused state in a telephoto end state, and FIG. 4B is an image stabilization correction in an infinitely focused state in a telephoto end state. It is a lateral aberration diagram after. 1 is a cross-sectional view of a single-lens reflex camera equipped with a photographing lens according to the present embodiment. It is a flowchart for demonstrating the manufacturing method of the imaging lens which concerns on this embodiment.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the photographic lens SL of this embodiment includes, in order from the object side, a first lens group G1 having a negative refractive power as a front group, a second lens group G2 having a positive refractive power, and a rear group. As a third lens group G3 having a negative refractive power and a fourth lens group G4 having a positive refractive power. When the photographic lens SL is zoomed from the wide-angle end state (the shortest focal length state) to the telephoto end state (the longest focal length state), the lens groups move together in the optical axis direction. The distance between the first lens group G1 and the second lens group G2 decreases, the distance between the second lens group G2 and the third lens group G3 increases, and the distance between the third lens group G3 and the fourth lens group G4 increases. The distance between the lens groups is changed so that the distance is reduced. With such a configuration, the photographic lens SL can achieve both a high angle of view and a high anti-vibration performance, and can obtain excellent optical performance.

  In the photographic lens SL, it is desirable that at least a part or all of the rear group is a vibration-proof lens group that moves so as to have a component that is substantially perpendicular to the optical axis. In general, in a negative leading zoom lens in which the front group is a negative lens, the front group is the largest lens group and may be extended to the object side during focusing. For this reason, it is not preferable to set the front lens group as an anti-vibration lens group because the holding function and the driving function increase in size and complexity. In addition, if the lens group other than the front group and the rear group has a large amount of movement in the optical axis direction at the time of zooming, it becomes an anti-vibration lens group, which increases the size and complexity of the holding function and drive mechanism. It is not preferable. In particular, the lens group having a positive refractive power disposed between the front group and the rear group is a group in which decentration aberration is likely to occur, and a part or all of the lens group is a vibration-proof lens group. In such a case, it is difficult to achieve high anti-vibration performance, which is not preferable. The rear group can have a relatively small lens diameter, and the amount of movement of the rear group in the optical axis direction during zooming can be made smaller than the amount of movement of the other lens groups in the optical axis direction. It is also possible to fix in the middle. In addition, the rear group generates the least amount of decentration aberration in the lens group, and is suitable for the anti-vibration lens group.

  In addition to the above-described configuration, the photographic lens SL is configured as follows in the rear lens group that is the anti-vibration lens group, thereby realizing excellent anti-vibration performance even at a large aperture and an ultra-high angle of view. ing. That is, it is desirable that the photographing lens SL has an aperture stop S in the vicinity of the rear group. The configuration in the rear group includes a first negative lens component G3a having negative refractive power and a negative power in order from the aperture stop S side. It is desirable that the second negative lens G3b having a refracting power and a positive lens component G3c having a positive refracting power are included. Further, the lens surface of the first negative lens component G3a on the second negative lens component G3b side is formed so as to face a concave surface with respect to the second negative lens component G3b, and the second negative lens component G3b is a first negative lens component G3b. A negative meniscus lens shape with a concave surface facing the lens component G3a is desirable. In addition, it is desirable that at least one of the lens surfaces constituting the first negative lens component G3a, the second negative lens component G3b, and the positive lens component G3c has an aspherical surface. With such a configuration, it is possible to prevent the lens group disposed on the image side of the rear group from increasing in size. Further, if the first negative lens component G3a, the second negative lens component G3b, and the positive lens component G3c are the anti-vibration lens group, the eccentricity that occurs when the anti-vibration lens group moves in a direction substantially perpendicular to the optical axis. The coma aberration and the one-sided (asymmetric) aberration of the meridional image surface / sagittal image surface can be minimized. The anti-vibration lens group may include a first negative lens component G3a and a second negative lens component G3b, and the positive lens component G3c is fixed at a position substantially perpendicular to the optical axis during image stabilization. It is also good.

  In addition to the above-described configuration, at least one of the lens surfaces constituting the first negative lens component G3a, the second negative lens component G3b, and the positive lens component G3c, which are the anti-vibration lens group, has an aspheric surface. Of spherical aberration that occurs when the lens is made brighter (especially brighter than about F2.8), and eccentric coma that occurs when the anti-vibration lens group moves in a direction substantially perpendicular to the optical axis, and the meridional image surface and sagittal image surface. One-sided (asymmetric) aberration can be minimized.

  Further, the positive lens component G3c has a positive refractive power, and thus has an effect of reducing the outer diameter of the lens group disposed on the image side of the rear group. The positive lens component G3c is preferably a biconvex single lens, and the decentration coma aberration generated when the anti-vibration lens group moves in a direction substantially perpendicular to the optical axis and the meridional image surface / sagittal image surface. One-sided aberration can be minimized.

  Further, if the first negative lens component G3a, the second negative lens component G3b, and the positive lens component G3c are all formed of a single lens, color field curvature aberration is likely to occur in the telephoto end state. If a low-dispersion glass material is selected as the lens medium, it is possible to suppress the curvature of field aberration of the color to some extent, but the refractive index of the glass material decreases, and there is a trade-off relationship with the eccentric coma aberration. Therefore, in the photographic lens SL, it is desirable that at least one of the first negative lens component G3a, the second negative lens component G3b, and the positive lens component G3c is a cemented lens in which a negative lens and a positive lens are cemented. It is possible to satisfactorily correct the color field curvature aberration in the state. Two or more of these lens components may be cemented lenses, but it is preferable that the two lens components other than the cemented lens are single lenses for weight reduction.

  Further, when one lens component is used as a cemented lens in this way, it is desirable that the cemented surface of the cemented lens has a concave surface with respect to the aperture stop S, so that the occurrence of color field curvature aberration due to image stabilization is improved. Can be suppressed.

  In the photographic lens SL, the rear group includes a first negative lens component G3a, a second negative lens component G3b, and a positive lens component G3c, and is adjacent to the outside of the first negative lens component G3a or the positive lens component G3c. It is possible to add other lens components.

  The photographing lens SL has a radius of curvature of the surface of the first negative lens component G3a on the second negative lens component G3b side as r1, and a radius of curvature of the surface of the second negative lens component G3b on the first negative lens component G3a side. When r2, it is desirable to satisfy the following conditional expression (1).

│r1│> │r2│ (1)

  Conditional expression (1) is a conditional expression for defining an air lens formed by the first negative lens component G3a and the second negative lens component G3b. That is, the conventional telephoto vibration-proof lens group has a configuration in which the absolute value of the radius of curvature is smaller on the aperture side, but in the photographing lens SL that satisfies the conditional expression (1), the first negative lens component The air lens formed by G3a and the second negative lens component G3b has a larger absolute value of the radius of curvature at r1 on the aperture side. By satisfying the conditional expression (1), the image stabilizing lens group can be configured to be suitable for the photographic lens SL having a high angle of view.

  The photographing lens SL has a radius of curvature of the surface of the first negative lens component G3a on the second negative lens component G3b side as r1, and a radius of curvature of the surface of the second negative lens component G3b on the first negative lens component G3a side. When r2, it is desirable that the following conditional expression (2) is satisfied.

0.0 <Fa <0.5 (2)
However, Fa represents a variable defined by the following equation.

Fa = (r1 + r2) / max (| r1 |, | r2 |)
However, max () is a function that returns the maximum value among a plurality of numerical values.

  Conditional expression (2) is a conditional expression for defining an appropriate relationship between the curvature radii r1 and r2 of the air lens formed by the first negative lens component G3a and the second negative lens component G3b. By satisfying the conditional expression (2), the image stabilizing lens group can be configured to be suitable for the photographing lens SL having a high angle of view. Further, it is possible to minimize the inclination of the image plane that occurs when the image stabilizing lens group moves in a direction substantially perpendicular to the optical axis.

  In addition, it is desirable that the photographic lens SL satisfies the following conditional expression (3) when the focal length of the rear lens group that is a vibration-proof lens group is Fg3 and the focal length of the positive lens component G3c is Fg3c.

0.5 <Fb <2.0 (3)
However, Fb represents a variable defined by the following equation.

Fb = Fg3c / | Fg3 |

  Conditional expression (3) is a conditional expression for prescribing the ratio of the focal length of the positive lens component G3c to the focal length of the rear group, which is the anti-vibration lens group. By satisfying this conditional expression (3), it is possible to prevent the lens group disposed on the image side from becoming large while the anti-vibration lens group has high anti-vibration performance. If the lower limit of conditional expression (3) is not reached, the outer diameter of the lens group disposed on the image side of the rear group becomes smaller, but the focal lengths of the first negative lens component G3a and the second negative lens component G3b are also relative. This is not preferable because the image stabilization performance and basic optical performance deteriorate. On the other hand, if the upper limit value of conditional expression (3) is exceeded, the outer diameter of the lens group disposed on the image side of the rear group becomes large, and the anti-vibration lens group becomes unsuitable for the photographing lens SL with a high field angle. It is not preferable.

  FIG. 17 is a schematic cross-sectional view of a single-lens reflex camera 1 (hereinafter simply referred to as a camera) as an optical apparatus including the above-described photographing lens SL. In this camera 1, light from an object (subject) (not shown) is collected by the taking lens 2 (shooting lens SL) 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. Note that the camera 1 illustrated in FIG. 17 may be configured to hold the photographing lens SL in a detachable manner, or may be formed integrally with the photographing lens SL. A camera without a quick return mirror may also be used.

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

  In this embodiment, the lens system is composed of four movable groups. However, other lens groups are added between the lens groups, or other lenses are provided adjacent to the image side or object side of the lens system. It is also possible to add groups.

  In the present embodiment, the photographic lens SL having a four-group configuration is shown. However, the above-described configuration conditions and the like can be applied to other image configurations such as the fifth group and the sixth 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. The lens component refers to a single lens or a cemented lens in which a plurality of lenses are bonded together.

  In addition, in order from the object side, the photographing lens SL of the present embodiment includes a first lens group G1 having a negative refractive power as a front group, a second lens group G2 having a negative refractive power, and a first lens group having a positive refractive power. The third lens group G3, the fourth lens group G4 having negative refractive power as the rear group, and the fifth lens group G5 having positive refractive power may be used.

  In addition, the photographing lens SL of the present embodiment has an open F number of about 2.8 and a zoom ratio of about 2 to 2.5, but may be a single focus lens that does not change the focal length. The angle of view is preferably about 100 ° or more at the wide-angle end state and about 50 ° at the telephoto end state.

  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 photographic lens SL of the present embodiment will be described with reference to FIG. First, each lens is arranged and a lens group is prepared (step S100). At this time, the first lens group G1 having a negative refractive power as the front group is disposed closest to the object side, and the third lens group G3 having a negative refractive power as the rear group is disposed closer to the image side than the front group. A fourth lens group G4 having a positive refractive power is disposed between the first lens group G1 and the third lens group G3. The third lens group G3 includes a first negative lens component G3a having a negative refractive power, a negative meniscus second negative lens component G3b having a negative refractive power, and a positive lens component having a positive refractive power. G3c, an air lens between which the second negative lens component G3b is located between the first negative lens component G3a and the positive lens component G3c, and between the first negative lens component G3a and the second negative lens component G3b Are arranged in a biconvex shape, and at least one of the first negative lens component G3a, the second negative lens component G3b, and the positive lens component G3c has an aspherical surface.

  Specifically, in this embodiment, for example, in order from the object side, a double-sided aspheric negative meniscus lens L11 having a convex surface facing the object side, a biconcave lens L12, and an image-side lens surface are both aspherical surfaces formed by resin molding. A concave lens L13 and a biconvex lens L14 are arranged to form the first lens group G1, and a cemented lens CL21 and a biconvex lens L23 formed by bonding a negative meniscus lens L21 having a convex surface facing the object side and a biconvex lens L22 are arranged. The second lens group G2, and a first negative lens comprising an aperture stop S, a cemented lens CL31 formed by bonding a positive meniscus lens (positive lens) L31 having a concave surface facing the object side and a biconcave lens (negative lens) L32 A component G3a, a second negative lens component G3b including a negative meniscus lens L33 having a concave surface facing the first negative lens component G3a, and A positive lens component G3c composed of a biconvex lens L34 is arranged to form a third lens group G3. A double cemented lens CL41 of a biconvex lens L41 and a biconcave lens L42, a biconvex lens L43, and a negative meniscus having a convex surface facing the object side. A fourth cemented lens group G4 is formed by arranging a three-piece cemented lens CL42 with a negative meniscus lens L46 in which the image-side lens surfaces of the lens L44 and the biconvex lens L45 are aspherical and the concave surface facing the object side. The lens groups prepared in this way are arranged to manufacture the photographing lens SL.

  At this time, at least a part of the third lens group G3 as the rear group is arranged so as to move so as to have a component substantially perpendicular to the optical axis (step S200).

  Embodiments of the present application will be described below with reference to the accompanying drawings. 1, 5, and 9 show the configuration of the photographic lenses SL (SL <b> 1 to SL <b> 4) according to each embodiment, the refractive power distribution, and the movement of each lens group during zooming to the telephoto end. Each of the lens groups moves on the optical axis along a zoom orbit indicated by an arrow in the drawing at the time of zooming to the telephoto end. As shown in FIG. 1, the photographing lens SL1 according to the first example has a four-group configuration, and in order from the object side, the first lens group G1 (front group) having a negative refractive power and a positive refractive power. The second lens group G2 includes a third lens group G3 (rear group) having a negative refractive power, and a fourth lens group G4 having a positive refractive power. The third lens group G3 includes, in order from the object side, the aperture stop S, a first negative lens component G3a having a negative refractive power, a second negative lens component G3b having a negative refractive power, and a positive refractive power. And a positive lens component G3c having When zooming from the wide-angle end state to the telephoto end state (ie, zooming), the distance between the first lens group G1 and the second lens group G2 decreases, and the second lens group G2 and the third lens group G3 The distance between the lens groups changes so that the distance between the third lens group G3 and the fourth lens group G4 decreases. In addition, camera shake correction (anti-vibration) is performed by moving at least one lens included in the third lens group G3 in a direction substantially perpendicular to the optical axis. Note that it is preferable that the aperture stop S of the third lens group G3 does not move in a direction substantially perpendicular to the optical axis at the time of image stabilization.

  As shown in FIGS. 5, 9, and 13, the photographing lenses SL <b> 2 to SL <b> 4 according to the second to fourth examples have a five-group configuration, and are first lenses having negative refractive power in order from the object side. A group G1 (front group), a second lens group G2 having positive refractive power, a third lens group G3 having positive refractive power, and a fourth lens group G4 (rear group) having negative refractive power And a fifth lens group G5 having a positive refractive power. The fourth lens group G4 includes, in order from the object side, an aperture stop S, a first negative lens component G4a having a negative refractive power, a second negative lens component G4b having a negative refractive power, and positive refraction. And a positive lens component G4c having force. During zooming from the wide-angle end state to the telephoto end state (ie, zooming), the distance between the first lens group G1 and the second lens group G2 decreases, and the second lens group G2 and the third lens group G3 The distance between each lens group changes so that the distance changes, the distance between the third lens group G3 and the fourth lens group G4 increases, and the distance between the fourth lens group G4 and the fifth lens group G5 decreases. To do. In addition, camera shake correction (anti-shake) is performed by moving lenses included in the fourth lens group G4 in a direction substantially perpendicular to the optical axis. In addition, it is preferable that the aperture stop S of the fourth lens group G4 is configured not to move in a direction substantially perpendicular to the optical axis during image stabilization.

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 tangent plane of the apex of each aspheric surface to each aspheric surface at height y. When S (y) is assumed, the radius of curvature of the reference sphere (paraxial radius of curvature) is r, the conic constant is κ, and the nth-order aspherical coefficient is An, the following equation (a) is obtained. In the following examples, “E−n” indicates “× 10 ⁻ⁿ ”.

S (y) = (y ² / r) / {1+ (1−κ × y ² / r ² ) ^1/2 }
^{+ A3 × │y│ 3 + A4 ×} │y│ 4 + A5 × │y│ 5 + A6 × │y│ 6 + A7 × │y│ 7
+ A8 x │y│ ⁸ + A9 x │y│ ⁹ + A10 x │y│ ¹⁰ + A11 x │y│ ¹¹ + A12 x │y│ ¹²
(A)

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

[First embodiment]
FIG. 1 is a diagram illustrating a configuration of a photographic lens SL1 according to the first example of the present application. In the photographic lens SL1 of FIG. 1, the first lens group G1 includes, in order from the object side, a double-sided aspheric negative meniscus lens L11 having a convex surface facing the object side, a biconcave lens L12, and an image side lens surface formed by resin molding. It is composed of an aspherical biconcave lens L13 and a biconvex lens L14.

  The second lens group G2 includes, in order from the object side, a cemented lens CL21 formed by bonding a negative meniscus lens L21 having a convex surface facing the object side and a biconvex lens L22, and a biconvex lens L23. By moving the cemented lens CL21 of the lens group G2 along the optical axis, focusing from an object at infinity to an object point at close range is performed. By adopting the inner focus in this way, the load applied to the focus motor is reduced during auto focus, and quick drive and power saving are possible.

  The first negative lens component G3a of the third lens group G3 includes, in order from the object side, a cemented lens CL31 formed by bonding a positive meniscus lens L31 having a concave surface facing the object side and a biconcave lens L32, and the second negative lens. The component G3b is composed of a negative meniscus lens L33 having a concave surface facing the first negative lens component G3a, and the positive lens component G3c is composed of a biconvex lens L34. By moving the third lens group G3 in a direction substantially perpendicular to the optical axis, image blur correction (anti-shake) due to vibration of the photographing lens SL1 is performed.

  In addition, the lens surface of the first negative lens component G3a on the second negative lens component G3b side included in the third lens group G3 is shaped so as to be concave toward the second negative lens component G3b. The second negative lens component G3b is a spherical surface, and is configured to have a negative meniscus lens shape with a concave surface facing the first negative lens component G3a. By adopting such a configuration, decentration coma and image plane tilt aberration, which are generated when the image stabilizing lens group is moved in a direction substantially perpendicular to the optical axis, are well corrected. In particular, both the basic spherical aberration and the decentering coma and the tilt aberration of the image plane that occur when the anti-vibration lens group moves in a direction substantially perpendicular to the optical axis with a large aperture of F-number 2.8. Is realized by adding an aspherical surface to the anti-vibration lens group.

  Further, by setting the first negative lens component G3a as a cemented lens CL31 having a cemented surface facing a concave surface with respect to the aperture stop S, color field curvature aberration, particularly color field curvature aberration on the telephoto side. Correction is being performed. Further, in the third lens group G3 which is an anti-vibration lens group, the super-wide-angle zoom is performed without deteriorating the anti-vibration performance by disposing the positive lens component G3c having a positive refractive power on the fourth lens group G4 side. This prevents an increase in the outer diameter of the fourth lens group G4, which is a problem with the lens.

  The fourth lens group G4 includes a biconvex lens L41 and a biconcave lens L42, a biconvex lens L41, a biconvex lens L43, a negative meniscus lens L44 having a convex surface facing the object side, a biconvex lens L45, and an image side. This lens surface is composed of a three-piece cemented lens CL42 with a negative meniscus lens L46 having an aspheric surface and a concave surface facing the object side.

  Table 1 below lists values of specifications of the photographing lens SL1 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. Also, 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 interval 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 curvature radius ∞ indicates a plane, and the refractive index of air 1.000 is omitted. The description of these symbols and the description of the specification table are the same in the following embodiments.

(Table 1)
Wide angle end Intermediate focal length Telephoto end f = 16.48 to 24.00 to 33.95
F.NO = 2.884 to 2.884 to 2.884
2ω = 108 °-84 °-63 °
Image height = 21.64 to 21.64 to 21.64
Optical total length = 170.00 to 164.15 to 161.56

Surface number Curvature radius Surface spacing Refractive index Abbe number
* 1 55.700 3.00 1.76690 46.85
* 2 14.895 12.67
3 -116.242 1.55 1.88300 40.76
4 156.108 2.36
5 -98.828 1.50 1.60172 53.82
6 74.978 0.20 1.55389 38.09
* 7 69.232 1.00
8 61.822 5.25 1.70021 28.28
9 -86.463 (d9)
10 52.267 1.05 1.84666 23.78
11 25.362 5.29 1.61469 43.67
12 -106.021 5.34
13 45.989 4.66 1.54698 54.26
14 -95.889 (d14)
15 ∞ 1.54 Aperture stop
16 -134.732 2.16 1.83241 24.09
17 -42.936 1.00 1.87807 37.28
* 18 46.466 4.55
19 -27.688 0.80 1.88300 40.76
20 -86.930 0.15
21 138.182 4.21 1.84666 23.78
22 -48.202 (d22)
23 33.276 8.09 1.49782 82.51
24 -34.972 1.10 1.85364 41.50
25 1185.909 0.05
26 52.640 5.97 1.49782 82.51
27 -53.870 0.15
28 47.612 1.10 1.88300 40.76
29 20.728 11.77 1.49782 82.51
30 -42.553 1.60 1.88300 40.76
* 31 -100.578 (Bf)

[Focal length of each lens group]
Lens group Start surface Focal length G1 1 -22.51
G2 10 35.50
G3 15 -46.90
G4 23 46.20

  In the first embodiment, the lens surfaces of the first surface, the second surface, the seventh surface, the eighteenth surface, and the thirty-first surface are formed in an aspherical shape. Table 2 below shows aspheric data, that is, the conic constant κ and the values of the aspheric constants A4, A6, A8, A10, and A12. In the first embodiment, the values of the aspheric constants A3, A5, A7, A9 and A11 are zero.

(Table 2)
1st surface 2nd surface 7th surface 18th surface 31st surface κ 1.000 0.203 -27.993 4.319 7.218
A4 -3.191E-06 6.823E-06 1.022E-05 -3.261E-06 1.031E-05
A6 3.912E-09 -5.387E-09 -3.084E-08 8.254E-10 8.099E-09
A8 -2.338E-12 1.031E-10 3.470E-11 -5.135E-11 -7.692E-12
A10 -3.890E-15 0.000E + 00 0.000E + 00 1.568E-13 1.022E-13
A12 4.026E-18 0.000E + 00 0.000E + 00 0.000E + 00 4.038E-18

  In the first embodiment, the axial air distance d9 between the first lens group G1 and the second lens group G2, the axial air distance d14 between the second lens group G2 and the third lens group G3, and the third lens group G3. The on-axis air gap d22 between the first lens group G4 and the fourth lens group G4 and the back focus Bf change during zooming. Table 3 below shows variable intervals at each focal length in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

(Table 3)
Wide angle end Intermediate focal length Telephoto end f 16.48 24.00 33.95
d9 27.04 11.16 1.80
d14 3.17 7.34 10.71
d22 12.50 5.84 0.23
Bf 38.48 48.50 63.23

  Table 4 below shows values corresponding to the conditional expression in the first embodiment. In Table 4, r1 is the radius of curvature of the surface of the first negative lens component G3a on the second negative lens component G3b side, and r2 is the radius of curvature of the surface of the second negative lens component G3b on the first negative lens component G3a side. , Fa represents the variable represented by the conditional expression (2), and Fb represents the variable represented by the conditional expression (3).

(Table 4)
Fg3 = -46.900
Fg3c = 42.650
(1) r1 = 46.466 r2 = −27.688
(2) Fa = 0.40
(3) Fb = 0.91

  FIG. 2A shows an aberration diagram in the infinite focus state in the wide-angle end state of the first embodiment, and FIG. 3A shows an aberration diagram in the infinite focus state in the intermediate focal length state. FIG. 4A shows an aberration diagram in the infinitely focused state in the telephoto end state. Further, FIG. 2B shows a lateral aberration diagram after the image stabilization when the image blur correction is performed in the infinitely focused state in the wide angle end state of the first embodiment, and infinite in the intermediate focal length state. FIG. 3B shows a lateral aberration diagram after image stabilization when the image blur correction is performed in the far focus state, and the image stabilization when the image blur correction is performed in the infinite focus state at the telephoto end state. FIG. 4B shows a lateral aberration diagram after vibration correction. Note that the lateral aberration after the image stabilization is an aberration when the image stabilization group G3 is moved by 0.2 (mm) in a direction substantially perpendicular to the optical axis. In each aberration diagram, FNO is an F number, Y is an image height, A is a half angle of view with respect to each image height, d is a d-line (λ = 587.6 nm), and g is a g-line (λ = 435.6). nm). In the aberration diagrams showing astigmatism, the solid line shows the sagittal image plane, and the broken line shows the meridional image plane. 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 explanation of this aberration diagram is the same in the following examples. As is apparent from each aberration diagram, in the photographing lens SL1 of the first example, the F number is 2.88 and a large aperture in each focal length state from the wide-angle end state to the telephoto end state. It can be seen that various aberrations including the above are corrected well and the imaging performance is excellent. In addition, it is a super-wide-angle high-power zoom that zooms from an ultra-wide angle of 100 ° or more to a standard angle of view of about 50 °, and has high anti-vibration performance that can correct aberrations during anti-vibration. The photographing lens SL1 having excellent optical performance can be obtained.

[Second Embodiment]
FIG. 5 is a diagram showing a configuration of the taking lens SL2 according to the second embodiment of the present application. In the photographic lens SL2 of FIG. 5, the first lens group G1 includes, in order from the object side, a double-sided aspheric negative meniscus lens L11 having a convex surface facing the object side, a biconcave lens L12, and an image side lens surface formed by resin molding. It is composed of an aspherical biconcave lens L13 and a biconvex lens L14.

  The second lens group G2 includes, in order from the object side, a cemented lens CL21 formed by bonding a negative meniscus lens L21 having a convex surface toward the object side and a biconvex lens L22. The second lens group G2 is arranged on the optical axis. Is moved from infinity to a close object point. By adopting the inner focus in this way, the load applied to the focus motor is reduced during auto focus, and quick drive and power saving are possible.

  The third lens group G3 includes a biconvex lens L31.

  The first negative lens component G4a of the fourth lens group G4 includes, in order from the object side, a cemented lens CL41 formed by bonding a positive meniscus lens L41 having a concave surface facing the object side and a biconcave lens L42. The component G4b includes a negative meniscus lens L43 having a concave surface facing the first negative lens component G4a, and the positive lens component G4c includes a biconvex lens L44. By moving the fourth lens group G4 in a direction substantially perpendicular to the optical axis, image blur correction (anti-shake) due to vibration of the photographing lens SL2 is performed.

  The lens surface on the second negative lens component G4b side of the first negative lens component G4a included in the fourth lens group G4 is non-shaped so as to face a concave surface with respect to the second negative lens component G4b. The second negative lens component G4b is a spherical surface, and is configured to have a negative meniscus lens shape with a concave surface facing the first negative lens component G4a. By adopting such a configuration, decentration coma and image plane tilt aberration, which are generated when the image stabilizing lens group is moved in a direction substantially perpendicular to the optical axis, are well corrected. In particular, both the basic spherical aberration and the decentering coma and the tilt aberration of the image plane that occur when the anti-vibration lens group moves in a direction substantially perpendicular to the optical axis with a large aperture of F-number 2.8. Is realized by adding an aspherical surface to the anti-vibration lens group.

  Further, the first negative lens component G4a is a cemented lens CL41 having a cemented surface facing the concave surface with respect to the aperture stop S, so that color field curvature aberration, particularly color field curvature aberration on the telephoto side. Correction is being performed. Further, in the fourth lens group G4 which is an anti-vibration lens group, the super-wide-angle zoom is performed without degrading the anti-shake performance by disposing the positive lens component G4c having a positive refractive power on the fifth lens group G5 side. The increase in the outer diameter of the fifth lens group G5, which is a problem with the lens, is prevented.

  The fifth lens group G5 includes a biconvex lens L51 and a biconcave lens L52, a cemented lens CL51, a biconvex lens L53, a negative meniscus lens L54 having a convex surface facing the object side, a biconvex lens L55, and an image side. The lens surface is composed of a three-piece cemented lens CL52 with a negative meniscus lens L56 having an aspherical surface and a concave surface facing the object side.

  Table 5 below lists values of specifications of the photographing lens SL2 according to the second example.

(Table 5)
Wide angle end Intermediate focal length Telephoto end f = 16.48 to 24.00 to 33.95
F.NO = 2.884 to 2.884 to 2.884
2ω = 108 °-84 °-63 °
Image height = 21.64 to 21.64 to 21.64
Optical total length = 169.32 ~ 161.04 ~ 164.28

Surface number Curvature radius Surface spacing Refractive index Abbe number
* 1 50.943 3.00 1.76690 46.85
* 2 14.571 12.74
3 -116.435 1.55 1.88300 40.76
4 155.379 2.28
5 -103.837 1.50 1.60972 53.12
6 71.864 0.20 1.55389 38.09
* 7 64.903 1.00
8 61.824 5.28 1.69694 28.43
9 -82.700 (d9)
10 57.224 1.05 1.84666 23.78
11 25.769 5.16 1.61699 43.08
12 -104.954 (d12)
13 45.674 4.89 1.55319 49.96
14 -82.700 (d14)
15 ∞ 1.54 Aperture stop
16 -137.172 2.14 1.84666 23.78
17 -44.700 1.00 1.87656 36.33
* 18 46.002 4.67
19 -27.961 0.80 1.88300 40.76
20 -90.721 0.15
21 124.583 4.30 1.84666 23.78
22 -50.211 (d22)
23 31.982 8.14 1.49782 82.51
24 -36.308 1.10 1.85275 41.53
25 459.166 0.05
26 52.795 5.92 1.49782 82.51
27 -53.353 0.15
28 48.593 1.10 1.88300 40.76
29 20.995 11.59 1.49782 82.51
30 -41.053 1.60 1.88300 40.76
* 31 -97.910 (Bf)

[Focal length of each lens group]
Lens group Start surface Focal length G1 1 -22.54
G2 10 85.65
G3 13 53.92
G4 15 -46.90
G5 23 46.71

  In the second embodiment, the lens surfaces of the first surface, the second surface, the seventh surface, the eighteenth surface, and the thirty-first surface are formed in an aspherical shape. Table 6 below shows the aspheric data, that is, the conic constant κ and the values of the aspheric constants A4, A6, A8, A10 and A12. In the second embodiment, the values of the aspheric constants A3, A5, A7, A9 and A11 are zero.

(Table 6)
1st surface 2nd surface 7th surface 18th surface 31st surface κ 1.000 0.205 -23.978 4.325 4.972
A4 -4.296E-06 7.276E-06 9.573E-06 -3.108E-06 1.066E-05
A6 3.898E-09 -6.558E-09 -2.997E-08 -3.879E-09 9.920E-09
A8 -2.279E-12 9.770E-11 3.432E-11 -1.171E-11 -5.022E-12
A10 -3.793E-15 0.000E + 00 0.000E + 00 3.651E-14 1.113E-13
A12 4.018E-18 0.000E + 00 0.000E + 00 0.000E + 00 4.038E-18

  In the second embodiment, the axial air distance d9 between the first lens group G1 and the second lens group G2, the axial air distance d12 between the second lens group G2 and the third lens group G3, and the third lens group G3. The axial air distance d14 between the first lens group G4 and the fourth lens group G4, the axial air distance d22 between the fourth lens group G4 and the fifth lens group G5, and the back focus Bf change during zooming. Table 7 below shows variable intervals at the respective focal lengths in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

(Table 7)
Wide angle end Intermediate focal length Telephoto end f 16.48 24.00 33.95
d9 27.37 11.19 1.59
d12 4.87 5.37 5.72
d14 3.17 6.90 9.74
d22 12.50 5.81 0.30
Bf 38.50 48.85 64.01

  Table 8 below shows values corresponding to the conditional expressions in the second embodiment. In Table 8, r1 is a radius of curvature of the surface of the first negative lens component G4a on the second negative lens component G4b side, and r2 is a radius of curvature of the surface of the second negative lens component G4b on the first negative lens component G4a side. , Fa represents the variable represented by the above conditional expression (2), and Fb represents the variable represented by the above conditional expression (3) (subscript “3” is replaced with “4”). In the following third and fourth embodiments, the description of this symbol is the same.

(Table 8)
Fg4 = -46.900
Fg4c = 42.751
(1) r1 = 46.002 r2 = -27.961
(2) Fa = 0.39
(3) Fb = 0.91

  FIG. 6A shows an aberration diagram in the infinite focus state in the wide-angle end state of the second embodiment, and FIG. 7A shows an aberration diagram in the infinite focus state in the intermediate focal length state. FIG. 8A shows an aberration diagram in the infinitely focused state in the telephoto end state. Further, FIG. 6B shows a lateral aberration diagram after image stabilization when the image blur correction is performed in the infinitely focused state in the wide-angle end state of the second embodiment, and infinite in the intermediate focal length state. FIG. 7B shows a lateral aberration diagram after image stabilization when the image blur correction is performed in the far focus state, and the image stabilization when the image blur correction is performed in the infinite focus state at the telephoto end state. FIG. 8B shows a lateral aberration diagram after the vibration correction. As is apparent from each aberration diagram, in the photographing lens SL2 of the second example, the F number is 2.88 and a large aperture in each focal length state from the wide-angle end state to the telephoto end state. It can be seen that various aberrations including the above are corrected well and the imaging performance is excellent. In addition, it is a super-wide-angle high-power zoom that zooms from an ultra-wide angle of 100 ° or more to a standard angle of view of about 50 °, and has high anti-vibration performance that can correct aberrations during anti-vibration. The photographing lens SL2 having excellent optical performance can be obtained.

[Third embodiment]
FIG. 9 is a diagram showing a configuration of the taking lens SL3 according to the third example of the present application. 9, the first lens group G1 includes, in order from the object side, a double-sided aspheric negative meniscus lens L11 having a convex surface facing the object side, a biconcave lens L12, and an image side lens surface formed by resin molding. It is composed of an aspherical biconcave lens L13 and a biconvex lens L14.

  The second lens group G2 includes, in order from the object side, a cemented lens CL21 formed by bonding a negative meniscus lens L21 having a convex surface toward the object side and a biconvex lens L22. The second lens group G2 is arranged on the optical axis. Is moved from infinity to a close object point. By adopting the inner focus in this way, the load applied to the focus motor is reduced during auto focus, and quick drive and power saving are possible.

  The third lens group G3 includes a biconvex lens L31.

  The first negative lens component G4a of the fourth lens group G4 includes, in order from the object side, a cemented lens CL41 formed by bonding a positive meniscus lens L41 having a concave surface facing the object side and a biconcave lens L42. The component G4b includes a negative meniscus lens L43 having a concave surface facing the first negative lens component G4a, and the positive lens component G4c includes a biconvex lens L44. By moving the fourth lens group G4 in a direction substantially perpendicular to the optical axis, image blur correction (anti-shake) due to vibration of the photographing lens SL3 is performed.

  The lens surface on the second negative lens component G4b side of the first negative lens component G4a included in the fourth lens group G4 is shaped so as to have a concave surface facing the second negative lens component G4b. The second negative lens component G4b has a negative meniscus lens shape with a concave surface facing the first negative lens component G4a, and the surface on the positive lens component G4c side is an aspherical surface. By adopting such a configuration, decentration coma and image plane tilt aberration, which are generated when the image stabilizing lens group is moved in a direction substantially perpendicular to the optical axis, are well corrected. In particular, both the basic spherical aberration and the decentering coma and the tilt aberration of the image plane that occur when the anti-vibration lens group moves in a direction substantially perpendicular to the optical axis with a large aperture of F-number 2.8. Is realized by adding an aspherical surface to the anti-vibration lens group.

  Further, the first negative lens component G4a is a cemented lens CL41 having a cemented surface facing the concave surface with respect to the aperture stop S, so that color field curvature aberration, particularly color field curvature aberration on the telephoto side. Correction is being performed. In addition, in the fourth lens group G4 that is the anti-vibration lens group, the super-wide-angle zoom can be performed without degrading the anti-vibration performance by disposing the positive lens component G4c having a positive refractive power on the fifth lens group G5 side. This prevents an increase in the outer diameter of the fifth lens group G5, which is a problem with the lens.

  The fifth lens group G5 includes a biconvex lens L51 and a biconcave lens L52, which are a cemented lens CL51, a biconvex lens L53, a negative meniscus lens L54 having a convex surface facing the object side, a biconvex lens L55, and an image side. The lens surface is composed of a three-piece cemented lens CL52 with a negative meniscus lens L56 having an aspherical surface and a concave surface facing the object side.

  Table 9 below lists values of specifications of the photographing lens SL3 according to the third example.

(Table 9)
Wide angle end Intermediate focal length Telephoto end f = 16.48 to 24.00 to 33.95
F.NO = 2.884 to 2.884 to 2.884
2ω = 108 °-84 °-63 °
Image height = 21.64 to 21.64 to 21.64
Optical total length = 169.28-161.17-164.58

Surface number Curvature radius Surface spacing Refractive index Abbe number
* 1 52.973 3.00 1.76690 46.85
* 2 14.850 12.60
3 -119.014 1.55 1.88300 40.76
4 136.109 2.48
5 -97.824 1.50 1.57965 55.96
6 79.989 0.20 1.55389 38.09
* 7 72.446 1.00
8 64.497 5.09 1.69974 28.30
9 -87.132 (d9)
10 58.371 1.05 1.84666 23.78
11 26.261 5.08 1.61508 43.13
12 -102.896 (d12)
13 45.706 4.82 1.55450 50.90
14 -86.359 (d14)
15 ∞ 1.71 Aperture stop
16 -104.348 2.45 1.83374 24.06
17 -35.279 1.00 1.87668 36.40
18 49.535 4.55
19 -28.181 0.80 1.88300 40.76
* 20 -73.586 0.15
21 142.004 4.14 1.84666 23.78
22 -52.132 (d22)
23 32.791 8.24 1.49782 82.51
24 -35.532 1.10 1.84809 41.65
25 1291.165 0.05
26 50.902 6.05 1.49782 82.51
27 -55.654 0.15
28 48.297 1.10 1.88300 40.76
29 20.801 11.80 1.49782 82.51
30 -41.073 1.60 1.88300 40.76
* 31 -102.841 (Bf)

[Focal length of each lens group]
Lens group Start surface Focal length G1 1 -22.58
G2 10 86.36
G3 13 54.61
G4 15 -46.90
G5 23 46.12

  In the third embodiment, the lens surfaces of the first surface, the second surface, the seventh surface, the twentieth surface, and the thirty-first surface are formed in an aspherical shape. Table 10 below shows the aspheric data, that is, the conical number κ and the values of the aspheric constants A4, A6, A8, A10 and A12. In the third embodiment, the values of the aspheric constants A3, A5, A7, A9 and A11 are 0.

(Table 10)
1st surface 2nd surface 7th surface 20th surface 31st surface κ 1.000 0.212 -31.468 0.586 5.145
A4 -3.243E-06 7.194E-06 9.425E-06 1.313E-07 1.073E-05
A6 3.427E-09 -2.832E-09 -3.037E-08 9.955E-10 8.287E-09
A8 -2.701E-12 9.233E-11 3.487E-11 -9.031E-14 -3.717E-12
A10 -3.037E-15 0.000E + 00 0.000E + 00 7.838E-15 1.076E-13
A12 3.682E-18 0.000E + 00 0.000E + 00 0.000E + 00 4.038E-18

  In the third example, the axial air distance d9 between the first lens group G1 and the second lens group G2, the axial air distance d12 between the second lens group G2 and the third lens group G3, and the third lens group G3. The axial air distance d14 between the first lens group G4 and the fourth lens group G4, the axial air distance d22 between the fourth lens group G4 and the fifth lens group G5, and the back focus Bf change during zooming. Table 11 below shows variable intervals at each focal length in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

(Table 11)
Wide angle end Intermediate focal length Telephoto end f 16.48 24.00 33.95
d9 26.94 11.02 1.61
d12 4.95 5.40 5.76
d14 3.17 6.96 10.01
d22 12.50 5.73 0.15
Bf 38.46 48.80 63.78

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

(Table 12)
Fg4 = -46.900
Fg4c = 45.484
(1) r1 = 49.53 r2 = −28.18
(2) Fa = 0.43
(3) Fb = 0.97

  FIG. 10A shows an aberration diagram in the infinite focus state in the wide-angle end state of the third embodiment, and FIG. 11A shows an aberration diagram in the infinite focus state in the intermediate focal length state. FIG. 12A shows an aberration diagram in the infinitely focused state in the telephoto end state. Further, FIG. 10B shows a lateral aberration diagram after image stabilization when the image blur correction is performed in the infinitely focused state in the wide-angle end state of the third embodiment, and infinite in the intermediate focal length state. FIG. 11B shows a lateral aberration diagram after the image stabilization when the image blur correction is performed in the far focus state, and the image stabilization when the image blur correction is performed in the infinite focus state at the telephoto end state. FIG. 12B shows a lateral aberration diagram after the vibration correction. As is apparent from each aberration diagram, in the photographing lens SL3 of the third example, the F number is 2.88 and a large aperture in each focal length state from the wide-angle end state to the telephoto end state. It can be seen that various aberrations including the above are corrected well and the imaging performance is excellent. In addition, it is a super-wide-angle high-power zoom that zooms from an ultra-wide angle of 100 ° or more to a standard angle of view of about 50 °, and has high anti-vibration performance that can correct aberrations during anti-vibration. The photographing lens SL3 having excellent optical performance can be obtained.

[Fourth embodiment]
FIG. 13 is a diagram showing a configuration of the taking lens SL4 according to the fourth example of the present application. In the photographic lens SL4 of FIG. 13, the first lens group G1 includes, in order from the object side, a double-sided aspheric negative meniscus lens L11 having a convex surface facing the object side, a biconcave lens L12, and an image side lens surface formed by resin molding. It is composed of an aspherical biconcave lens L13 and a biconvex lens L14.

  The second lens group G2 includes, in order from the object side, a cemented lens CL21 formed by bonding a negative meniscus lens L21 having a convex surface toward the object side and a biconvex lens L22. The second lens group G2 is arranged on the optical axis. Is moved from infinity to a close object point. By adopting the inner focus in this way, the load applied to the focus motor is reduced during auto focus, and quick drive and power saving are possible.

  The third lens group G3 includes a biconvex lens L31.

  The first negative lens component G4a of the fourth lens group G4 includes, in order from the object side, a cemented lens CL41 formed by bonding a positive meniscus lens L41 having a concave surface facing the object side and a biconcave lens L42. The component G4b is composed of a negative meniscus lens L43 having a concave surface facing the first negative lens component G4a, and the positive lens component G4c is composed of a biconvex lens L44 whose surface on the fifth lens group G5 side is aspheric. Yes. By moving the fourth lens group G4 in a direction substantially perpendicular to the optical axis, image blur correction (anti-shake) due to vibration of the photographing lens SL4 is performed.

  The lens surface on the second negative lens component G4b side of the first negative lens component G4a included in the fourth lens group G4 is shaped so as to have a concave surface facing the second negative lens component G4b. The second negative lens component G4b has a negative meniscus lens shape with a concave surface facing the first negative lens component G4a. By adopting such a configuration, decentration coma and image plane tilt aberration, which are generated when the image stabilizing lens group is moved in a direction substantially perpendicular to the optical axis, are well corrected. In particular, both the basic spherical aberration and the decentering coma and the tilt aberration of the image plane that occur when the anti-vibration lens group moves in a direction substantially perpendicular to the optical axis with a large aperture of F-number 2.8. Is realized by adding an aspherical surface to the anti-vibration lens group.

  Further, the first negative lens component G4a is a cemented lens CL41 having a cemented surface facing the concave surface with respect to the aperture stop S, so that color field curvature aberration, particularly color field curvature aberration on the telephoto side. Correction is being performed. In addition, in the fourth lens group G4 that is the anti-vibration lens group, the super-wide-angle zoom can be performed without degrading the anti-vibration performance by disposing the positive lens component G4c having a positive refractive power on the fifth lens group G5 side. This prevents an increase in the outer diameter of the fifth lens group G5, which is a problem with the lens.

  The fifth lens group G5 includes, in order from the object side, a biconvex lens L51 and a biconcave lens L52, a biconvex lens CL51, a biconvex lens L53, a negative meniscus lens L54 having a convex surface facing the object side, a biconvex lens L55, and an image side. The lens surface is composed of a three-piece cemented lens CL52 with a negative meniscus lens L56 having an aspherical surface and a concave surface facing the object side.

  Table 13 below lists values of specifications of the photographic lens SL4 according to the fourth example.

(Table 13)
Wide angle end Intermediate focal length Telephoto end f = 16.48 to 24.00 to 33.95
F.NO = 2.884 to 2.884 to 2.884
2ω = 108 °-84 °-63 °
Image height = 21.64 to 21.64 to 21.64
Optical total length = 169.35 to 160.85 to 164.01

Surface number Curvature radius Surface spacing Refractive index Abbe number
* 1 54.854 3.00 1.76690 46.85
* 2 14.895 12.52
3 -119.197 1.55 1.88300 40.76
4 153.800 2.37
5 -99.957 1.50 1.58117 55.80
6 70.459 0.20 1.55389 38.09
* 7 70.337 1.00
8 58.073 5.12 1.69870 28.35
9 -102.834 (d9)
10 60.699 1.05 1.84666 23.78
11 26.752 5.02 1.61593 42.00
12 -96.705 (d12)
13 44.671 4.86 1.55420 52.03
14 -85.562 (d14)
15 ∞ 1.69 Aperture stop
16 -107.454 2.32 1.83400 24.05
17 -45.271 1.00 1.87834 37.97
18 48.988 4.58
19 -27.883 0.80 1.88105 40.81
20 -84.274 0.15
21 137.079 4.27 1.84666 23.78
* 22 -48.636 (d22)
23 32.159 8.01 1.49782 82.51
24 -36.284 1.10 1.85199 41.55
25 486.061 0.05
26 51.543 6.05 1.49782 82.51
27 -53.717 0.15
28 50.562 1.10 1.88300 40.76
29 21.393 11.71 1.49782 82.51
30 -39.794 1.60 1.88300 40.76
* 31 -91.946 (Bf)

[Focal length of each lens group]
Lens group Start surface Focal length G1 1 -22.56
G2 10 86.18
G3 13 53.67
G4 15 -46.90
G5 23 46.64

  In the fourth embodiment, the lens surfaces of the first surface, the second surface, the seventh surface, the twenty-second surface, and the thirty-first surface are formed in an aspherical shape. Table 14 below shows the aspheric data, that is, the conical number κ and the values of the aspheric constants A4, A6, A8, A10 and A12. In the fourth embodiment, the values of the aspheric constants A3, A5, A7, A9 and A11 are 0.

(Table 14)
1st surface 2nd surface 7th surface 22nd surface 31st surface κ 1.000 0.180 -28.387 0.716 4.852
A4 -3.651E-06 5.946E-06 1.150E-05 3.171E-07 1.066E-05
A6 3.597E-09 -6.965E-09 -2.848E-08 4.652E-10 9.341E-09
A8 -1.035E-12 8.384E-11 3.562E-11 -1.605E-12 -1.234E-13
A10 -4.251E-15 0.000E + 00 0.000E + 00 1.111E-14 9.226E-14
A12 3.834E-18 0.000E + 00 0.000E + 00 0.000E + 00 4.038E-18

  In the fourth example, the axial air gap d9 between the first lens group G1 and the second lens group G2, the axial air gap d12 between the second lens group G2 and the third lens group G3, and the third lens group G3. The axial air distance d14 between the first lens group G4 and the fourth lens group G4, the axial air distance d22 between the fourth lens group G4 and the fifth lens group G5, and the back focus Bf change during zooming. Table 15 below shows variable intervals at the respective focal lengths in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

(Table 15)
Wide angle end Intermediate focal length Telephoto end f 16.48 24.00 33.95
d9 27.36 11.18 1.63
d12 5.02 5.40 5.73
d14 3.17 6.73 9.47
d22 12.50 5.72 0.15
Bf 38.53 49.04 64.26

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

(Table 16)
Fg4 = -46.900
Fg4c = 42.852
(1) r1 = 48.99 r2 = −27.88
(2) Fa = 0.43
(3) Fb = 0.91

  FIG. 14A shows an aberration diagram in the infinitely focused state in the wide-angle end state of this fourth embodiment, and FIG. 15A shows an aberration diagram in the infinitely focused state in the intermediate focal length state. FIG. 16A shows an aberration diagram in the infinitely focused state in the telephoto end state. Further, FIG. 14B shows a lateral aberration diagram after image stabilization when the image blur correction is performed in the infinitely focused state in the wide-angle end state of the fourth embodiment, and infinite in the intermediate focal length state. FIG. 15B shows a lateral aberration diagram after image stabilization when the image blur correction is performed in the far focus state, and the image stabilization when the image blur correction is performed in the infinite focus state at the telephoto end state. FIG. 16B shows a lateral aberration diagram after shake correction. As is apparent from each aberration diagram, in the photographing lens SL4 of the fourth example, the F number is 2.88 and a large aperture in each focal length state from the wide-angle end state to the telephoto end state. It can be seen that various aberrations including the above are corrected well and the imaging performance is excellent. In addition, it is a super-wide-angle high-power zoom that zooms from an ultra-wide angle of 100 ° or more to a standard angle of view of about 50 °, and has high anti-vibration performance that can correct aberrations during anti-vibration. A photographing lens SL4 having excellent optical performance can be obtained.

SL (SL1 to SL4) Shooting lens G1 First lens group G2 Second lens group G3 Third lens group G4 Fourth lens group G3a, G4a First negative lens component G3b, G4b Second negative lens component G3c, G4c Positive lens component S Aperture stop 1 SLR camera (optical equipment)

Claims (9)

A front group disposed on the most object side and having a negative refractive power;
A rear group disposed on the image side of the front group, having a negative refractive power, and moving so that at least a part thereof has a component substantially perpendicular to the optical axis,
The rear group is
A first negative lens component having a negative refractive power; a second negative lens component having a negative refractive power; and a positive lens component having a positive refractive power;
The second negative lens component is disposed between the first negative lens component and the positive lens component;
The lens surface on the second negative lens component side of the first negative lens component is formed so as to face a concave surface with respect to the second negative lens component,
The second negative lens component has a negative meniscus lens shape with a concave surface facing the first negative lens component,
A photographic lens having an aspherical surface on at least one of the first negative lens component, the second negative lens component, and the positive lens component.   An aperture stop is provided in the vicinity of the rear group, and the rear group is arranged in the order of the first negative lens component, the second negative lens component, and the positive lens component from the aperture stop side. Item 4. The taking lens according to Item 1.   The photographing lens according to claim 1, wherein the positive lens component has a biconvex shape.   The photographing according to claim 1, wherein at least one of the first negative lens component, the second negative lens component, and the positive lens component is a cemented lens in which a negative lens and a positive lens are cemented. lens   The photographic lens according to claim 4, wherein the cemented surface of the cemented lens has a concave surface facing the aperture stop. A second lens group disposed between the first lens group as the front group and the third lens group as the rear group, and having a positive refractive power;
A fourth lens group disposed on the image side of the third lens group and having a positive refractive power;
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, The taking lens according to any one of claims 1 to 5, wherein an interval between the third lens group and the fourth lens group changes.   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 decreases, and the distance between the second lens group and the third lens group increases, The photographic lens according to claim 6, wherein a distance between the third lens group and the fourth lens group decreases.   An optical apparatus comprising the photographic lens according to claim 1, which forms an image of an object on a predetermined image plane. A method of manufacturing a photographic lens having a front group having a negative refractive power and a rear group having a negative refractive power,
Placing the front group on the most object side,
The rear group is arranged on the image side from the front group,
A first negative lens component having a negative refractive power; a negative meniscus second negative lens component having a negative refractive power; and a positive lens component having a positive refractive power. The air lens located between the first negative lens component and the positive lens component and the air lens between the first negative lens component and the second negative lens component has a biconvex shape. Placed in the rear group,
At least one of the first negative lens component, the second negative lens component, and the positive lens component has an aspheric surface,
A method for manufacturing a photographic lens, wherein at least a part of the rear group is arranged so as to move so as to have a component substantially perpendicular to the optical axis.

Images