JP5344291B2 - Zoom lens, optical device, and method of manufacturing zoom lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide: a zoom lens, in which appropriate refractive powers of lens groups are set to minimize the deterioration of optical performance while ensuring a higher magnification; an optical device; and a method of manufacturing the zoom lens. <P>SOLUTION: The zoom lens includes: a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power, which are arranged in this order from the object side. The space of each the lens group is changed in magnification change from a wide-angle end state to a telescopic end state, the second lens group G2 includes at least three lenses having negative refractive power (lenses L21, L22 and L24 in Fig. 1) and at least one lens having positive refractive power (lens L23 in Fig. 1), and when the refractive index of d-beam (wavelength 587.56 nm) of the positive lens constituting the second lens group G2 is nd2, the condition of the expression 1.87&lt;nd2 is satisfied. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

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

  In recent years, zoom lenses have been made highly variable in magnification due to advances in optical design technology and manufacturing technology. For example, 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 negative refractive power arranged in order from the object side. There has been proposed a 5-group type zoom lens composed of a fourth lens group having a fifth lens group having a positive refractive power. (For example, see Patent Document 1).

JP 2006-227526 A

  However, the conventional zoom lens with a high zoom ratio has a problem that the optical performance during zooming is significantly deteriorated.

  The present invention has been made in view of such a problem, and a zoom lens and an optical apparatus in which the refractive power of an appropriate lens group is set so as to reduce deterioration in optical performance while achieving high zooming. It is another object of the present invention to provide a zoom lens manufacturing method.

In order to achieve such an object, the zoom lens of the present invention includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a positive refraction arranged in order from the object side. The third lens group having power, the fourth lens group having negative refracting power, and the fifth lens group having positive refracting power substantially consist of five lens groups, and from the wide-angle end state to the telephoto end upon zooming to the state, so that the distance between the lens units are changed, the fifth lens group and the third lens group and the third lens group moves toward the object side, the said second lens group first The four lens groups move, and the second lens group includes at least three lenses having negative refractive power and at least one lens having positive refractive power, and constitutes the second lens group. When the refractive index of the d-line (wavelength 587.56 nm) possessed by the positive lens is nd2, the following formula 1 87 <to satisfy the conditions of nd2.
The zoom lens according to the present invention 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, which are arranged in order from the object side. And a fourth lens group having negative refracting power and a fifth lens group having positive refracting power, and substantially consisting of five lens groups, each of which is used for zooming from the wide-angle end state to the telephoto end state. The distance between the lens groups is changed, and the second lens group includes at least three lenses having a negative refractive power and at least one lens having a positive refractive power. When the refractive index of the d-line (wavelength 587.56 nm) of the positive lens is nd2, the focal length of the fourth lens group is f4, and the focal length of the fifth lens group is f5, the following formula 1 .87 <nd2 and 0.80 <f5 / (− f4) <3.50 are satisfied
The zoom lens according to the present invention 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, which are arranged in order from the object side. And a fourth lens group having negative refracting power and a fifth lens group having positive refracting power, and substantially consisting of five lens groups, each of which is used for zooming from the wide-angle end state to the telephoto end state. The distance between the lens groups is changed, and the second lens group includes at least three lenses having a negative refractive power and at least one lens having a positive refractive power. When the refractive index of the d-line (wavelength 587.56 nm) of the positive lens is nd2, the focal length of the third lens group is f3, and the focal length of the fourth lens group is f4, the following formula 1 .87 <nd2 and 0.60 <f3 / (− f4) <1.20 are satisfied
The zoom lens according to the present invention 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, which are arranged in order from the object side. And a fourth lens group having a negative refractive power and a fifth lens group having a positive refractive power, and at the time of zooming from the wide-angle end state to the telephoto end state, the first lens group and the first lens group The distance between the second lens group increases, the distance between the second lens group and the third lens group decreases, the distance between the third lens group and the fourth lens group increases, and the fourth lens The first lens group, the third lens group, and the fifth lens group move toward the object side so that the distance between the group and the fifth lens group decreases, and the second lens group and the fourth lens And the second lens group includes at least three lenses having negative refractive power and at least one lens. When the refractive index of the d line (wavelength 587.56 nm) of the positive lens constituting the second lens group is nd2, the following formula 1.87 <nd2 is satisfied. Satisfied.

During zooming from the wide-angle end state to the telephoto end state, the first lens group, the third lens group, and the fifth lens group move to the object side, and the second lens group and the fourth lens group. Preferably move .

Further, when the focal length of the fourth lens group is f4 and the focal length of the fifth lens group is f5, the following expression 0.80 <f5 / (− f4) <3.50 is satisfied. Is preferred.

Further, 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. Preferably, the distance between the third lens group and the fourth lens group is increased, and the distance between the fourth lens group and the fifth lens group is decreased .

Further, 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 0.50 <f3 / (− f4) <1.20 is satisfied. Is preferred.

Further, when the focal length of the second lens group is f2 and the focal length of the fourth lens group is f4, the condition of the following expression 0.30 <(− f2) / (− f4) <1.50 is satisfied. It is preferable to satisfy .

The second lens group includes a lens having negative refractive power, a lens having negative refractive power, a lens having positive refractive power, and a lens having negative refractive power, which are arranged in order from the object side. It is preferable to have .

The second lens group preferably has at least one aspheric surface .

Further, it is preferable that at least a part of the fourth lens group moves so as to have a component in a direction perpendicular to the optical axis .

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

Further, focusing from an infinitely distant object to a close object is preferably performed by moving at least a part of the second lens group in the optical axis direction .

  An optical apparatus according to the present invention includes any of the zoom lenses described above.

The zoom lens manufacturing method according to the present invention includes 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, arranged in order from the object side. A zoom lens manufacturing method comprising substantially five lens groups, including a three-lens group, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power, upon zooming from a state to a telephoto end state, so that the distance between the lens units are changed, wherein the first lens group third lens and the fifth lens group and group moves toward the object side, the second lens The second lens group includes at least three lenses having negative refractive power and at least one lens having positive refractive power, and the second lens group moves . The refractive index of the d-line (wavelength 587.56 nm) of the positive lens constituting the lens group is denoted by nd2. When I, the following conditional expression is satisfied: 1.87 <nd2.

  According to the present invention, it is possible to provide a zoom lens, an optical apparatus, and a zoom lens manufacturing method in which the refractive power of an appropriate lens group is set so as to reduce deterioration in optical performance while achieving high zooming. it can.

FIG. 3 is a cross-sectional configuration diagram of a zoom lens according to Example 1, where (W) shows a wide-angle end state, (M) shows an intermediate focal length state, and (T) shows a telephoto end state. FIG. 3A is a diagram illustrating various aberrations of the zoom lens according to the first example. FIG. 9A is a diagram illustrating various aberrations in an infinite focus state at a wide-angle end state, and FIG. FIG. 4C is a diagram of various aberrations in the infinite focus state at the telephoto end state. FIG. 4 is a cross-sectional configuration diagram of a zoom lens according to Example 2, where (W) shows a wide-angle end state, (M) shows an intermediate focal length state, and (T) shows a telephoto end state. FIG. 6 is a diagram illustrating various aberrations of the zoom lens according to Example 2, wherein (a) illustrates various aberrations in the infinite focus state at the wide-angle end state, and (b) illustrates various aberrations in the infinite focus state at the intermediate focal length state. FIG. 4C is a diagram of various aberrations in the infinite focus state at the telephoto end state. FIG. 6 is a cross-sectional configuration diagram of a zoom lens according to Example 3, where (W) shows a wide-angle end state, (M) shows an intermediate focal length state, and (T) shows a telephoto end state. FIG. 6A is a diagram illustrating various aberrations of the zoom lens according to Example 3, wherein FIG. 9A illustrates various aberrations in the infinite focus state at the wide-angle end state, and FIG. 9B illustrates various aberrations in the infinite focus state at the intermediate focal length state. FIG. 4C is a diagram of various aberrations in the infinite focus state at the telephoto end state. FIG. 10 is a cross-sectional configuration diagram of a zoom lens according to Example 4, where (W) shows a wide-angle end state, (M) shows an intermediate focal length state, and (T) shows a telephoto end state. FIG. 7A is a diagram illustrating various aberrations of the zoom lens according to Example 4; FIG. 9A is a diagram illustrating various aberrations in an infinite focus state at a wide-angle end state, and FIG. FIG. 4C is a diagram of various aberrations in the infinite focus state at the telephoto end state. FIG. 10 is a cross-sectional configuration diagram of a zoom lens according to Example 5, where (W) shows a wide-angle end state, (M) shows an intermediate focal length state, and (T) shows a telephoto end state. FIG. 7A is a diagram illustrating various aberrations of the zoom lens according to Example 5; FIG. 9A is a diagram illustrating various aberrations in the infinite focus state at the wide-angle end state, and FIG. FIG. 4C is a diagram of various aberrations in the infinite focus state at the telephoto end state. 1 is a schematic cross-sectional view of a digital single-lens reflex camera CAM (optical apparatus) including a zoom lens having the above configuration. It is a flowchart for demonstrating the manufacturing method of the zoom lens of the said structure.

  Hereinafter, preferred embodiments will be described with reference to the drawings. As shown in FIG. 1, the zoom lens according to the present embodiment includes a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a positive lens arranged in order from the object side. It has a third lens group G3 having a refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power, and changes from the wide-angle end state to the telephoto end state. The distance between the lens groups changes upon magnification, and the second lens group G2 includes at least three lenses having a negative refractive power and at least one lens having a positive refractive power. With this configuration, since the number of constituent lens groups is large, zooming can be shared among the groups, and high zooming can be easily performed.

  Further, when the refractive power of the d line (wavelength 587.56 nm) of the positive lens constituting the second lens group G2 is nd2, the condition of the following formula (1) is satisfied.

  1.87 <nd2 (1)

  The conditional expression (1) is a conditional expression for defining the refractive index of the positive lens constituting the second lens group G2, which is suitable for securing the imaging performance. If the lower limit value of conditional expression (1) is not reached, fluctuations in coma and imaging performance (for example, spherical aberration) in the telephoto end state are undesirably caused.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (1) to 1.895. In order to secure the effect of the present embodiment, it is more preferable to set the lower limit value of conditional expression (1) to 1.90.

  In the present embodiment, when the focal length of the second lens group G2 is f2, and the focal length of the fourth lens group G4 is f4, it is preferable that the condition of the following expression (2) is satisfied.

  0.30 <(− f2) / (− f4) <1.50 (2)

  Conditional expression (2) defines an appropriate ratio of the focal length of the fourth lens group G4 to the focal length of the second lens group G2. The present zoom lens can achieve good optical performance by satisfying conditional expression (2). If the upper limit of conditional expression (2) is exceeded, the refractive power of the fourth lens group G4 becomes too strong, and the positive distortion in the telephoto end state deteriorates. Further, the refractive power of the second lens group G2 becomes too weak, and it becomes difficult to secure the peripheral light amount in the wide-angle end state. On the other hand, if the lower limit of conditional expression (2) is not reached, the refractive power of the second lens group G2 becomes too strong, and it becomes difficult to correct off-axis aberrations, particularly field curvature and astigmatism in the wide-angle end state. .

  In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (2) to 1.20. Furthermore, in order to make the effect of the present embodiment more certain, it is preferable to set the upper limit of conditional expression (2) to 1.00. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (2) to 0.35.

  In the present embodiment, when the focal length of the third lens group G3 is f3 and the focal length of the fourth lens group G4 is f4, it is preferable that the condition of the following expression (3) is satisfied.

  0.50 <f3 / (− f4) <1.20 (3)

  Conditional expression (3) defines an appropriate ratio of the focal length of the fourth lens group G4 to the focal length of the third lens group G3. If the upper limit of conditional expression (3) is exceeded, the refractive power of the fourth lens group G4 becomes too strong, and it becomes difficult to correct spherical aberration in the telephoto end state. On the contrary, if the lower limit value of conditional expression (3) is not reached, the refractive power of the third lens group G3 becomes too strong, and it becomes difficult to correct spherical aberration and coma aberration in the wide-angle end state.

  In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (3) to 1.10. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (3) to 0.60.

  In the present embodiment, when the focal length of the fourth lens group G4 is f4 and the focal length of the fifth lens group G5 is f5, it is preferable that the condition of the following expression (4) is satisfied.

  0.80 <f5 / (− f4) <3.50 (4)

  Conditional expression (4) defines an appropriate ratio of the focal length of the fourth lens group G4 to the focal length of the fifth lens group G5. If the upper limit of conditional expression (4) is exceeded, the refractive power of the fourth lens group G4 becomes too strong, and it becomes difficult to correct spherical aberration in the telephoto end state. On the other hand, if the lower limit of conditional expression (4) is not reached, the refractive power of the fifth lens group G5 becomes too strong, making it difficult to correct coma and astigmatism in the wide-angle end state.

  In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (4) to 2.40. In order to secure the effect of the present embodiment, it is more preferable to set the upper limit of conditional expression (4) to 1.80. Furthermore, in order to make the effect of the present embodiment more certain, it is more preferable to set the upper limit value of the conditional expression (4) to 1.70.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (4) to 1.10. In order to secure the effect of the present embodiment, it is more preferable to set the lower limit of conditional expression (4) to 1.20.

  In the present embodiment, the second lens group G2 includes, in order from the object side, a lens having a negative refractive power, a lens having a negative refractive power, a lens having a positive refractive power, It is preferable to have a lens having a refractive power (in FIG. 1, the lenses L21, L22, L23, and L24 are applicable). According to the second lens group G2 in which the lenses are arranged in this order, the field curvature in the wide-angle end state and the spherical aberration in the telephoto end state can be reduced.

  In the present embodiment, it is preferable that the second lens group G2 has at least one aspherical surface (the lens L21 corresponds in FIG. 1). With this configuration, field curvature in the wide-angle end state can be reduced.

  In the present embodiment, it is preferable that at least a part of the fourth lens group G4 moves so as to have a component in a direction perpendicular to the optical axis. With this configuration, it is possible to suppress aberration fluctuations during image stabilization.

  In the present embodiment, it is preferable that at least a part of the third lens group G3 moves so as to have a component in a direction perpendicular to the optical axis. With this configuration, it is possible to suppress aberration fluctuations during image stabilization.

  In the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the first lens group G1, the third lens group G3, and the fifth lens group G5 move to the object side, and the second lens group G2 The fourth lens group G4 is preferably moved. With this configuration, a high zoom ratio can be achieved. In addition, various aberrations such as field curvature can be favorably corrected.

  In the present embodiment, it is preferable that focusing from an object at infinity to an object at a short distance is performed by moving at least a part of the second lens group G2 in the optical axis direction. With this configuration, it is possible to reduce various aberrations such as field curvature during focusing on a short-distance object.

  In the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group G1 and the second lens G2 increases, and the second lens group G2 and the third lens group G3 Preferably, the distance decreases, the distance between the third lens group G3 and the fourth lens group G4 increases, and the distance between the fourth lens group G4 and the fifth lens group G5 decreases. As a result, it is possible to ensure a predetermined zoom ratio while effectively correcting variations in spherical aberration and field curvature.

  FIG. 11 is a schematic cross-sectional view of a digital single-lens reflex camera CAM (optical apparatus) provided with the zoom lens having the above configuration as a photographing lens 1. In the digital single lens reflex camera CAM shown in FIG. 11, light from an object (subject) (not shown) is collected by the photographing lens 1 and focused 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 1 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 photograph an object (subject) with the camera CAM. Note that the camera CAM illustrated in FIG. 11 may hold the photographic lens 1 in a detachable manner, or may be molded integrally with the photographic lens 1. In addition, the zoom lens of the present embodiment can ensure a sufficiently long back focus, and the camera CAM may be a so-called single-lens reflex camera or a camera without a quick return mirror or the like.

  Next, a method for manufacturing the zoom lens having the above configuration will be described with reference to FIG. First, each lens (for example, the lenses L11 to L54 in the zoom lens according to the first embodiment shown in FIG. 1) is incorporated in a cylindrical barrel (step S1). When assembling the lenses into the lens barrel, the lenses may be incorporated into the lens barrel one by one in the order along the optical axis, or a part or all of the lenses may be integrally held by the holding member and then assembled with the lens barrel member. Good. Next, after each lens is incorporated in the lens barrel, it is confirmed whether an object image is formed in a state where each lens is incorporated in the lens barrel, that is, whether the centers of the lenses are aligned (step) S2). Subsequently, various operations of the zoom lens are confirmed (step S3). Examples of various operations include a zooming operation that performs zooming from the wide-angle end state to the telephoto end state, and a lens that performs focusing from a long-distance object to a short-distance object (in this embodiment, at least the second lens group G2). A focusing operation in which a part) moves along the optical axis direction, and at least a part of the lenses (in this embodiment, at least part of the third lens group G3 or at least part of the fourth lens group G4) For example, an image stabilization operation for moving the image so as to have a vertical component. Note that the order of confirming the various operations is arbitrary.

  Hereinafter, each example according to the present embodiment will be described with reference to the drawings. Tables 1 to 5 are shown below, but these are tables of specifications in the first to fifth examples.

  In [Overall Specifications], f represents the focal length of the entire lens system, FNO represents the F number, 2ω represents the angle of view, Y represents the image height, TL represents the total length of the lens system, and Bf represents the back focus.

  In [Lens data], the surface number is the order of the lens surfaces from the object side along the direction in which the light beam travels, r is the radius of curvature of each lens surface, and d is the next optical surface (or image from each optical surface). The distance between the surfaces which is the distance on the optical axis to the surface), nd is the refractive index for the d-line (wavelength 587.6 nm), and νd is the Abbe number for the d-line. When the lens surface is aspherical, an asterisk is attached to the surface number, and the paraxial radius of curvature is indicated in the column of the radius of curvature r. The curvature radius “0.0000” indicates a plane or an opening. Further, the description of the refractive index “1.00000” of air is omitted. In [variable surface interval data], Di (where i is an integer) indicates a variable surface interval of the i-th surface. In [Lens Group Data], the initial surface and focal length of each group are shown. In [Conditional Expression Corresponding Value], values corresponding to the conditional expressions (1) to (4) are shown.

In [Aspherical Data], the shape of the aspherical surface shown in [Lens Data] is shown by the following equation (a). That is, y is the height in the direction perpendicular to the optical axis, and S (y) is the distance (sag amount) along the optical axis from the tangent plane at the apex of the aspheric surface to the position on the aspheric surface at height y. When the radius of curvature (paraxial radius of curvature) of the reference spherical surface is r, the conic coefficient is K, and the n-th aspherical coefficient is An, the following equation (a) is given. In each example, the secondary aspheric coefficient A2 is 0, and the description thereof is omitted. E-n represents ^x10 -n. For example, 1.234E-05 = 1.234 × 10 ⁻⁵ .

S (y) = (y ² / r) / {1+ (1−K · y ² / r ² ) ^1/2 } + A 3 × | y ³ |
^{+ A4 × y 4 + A6 ×} y 6 + A8 × y 8 + A10 × y 10 + A12 × y 12 ... (a)

  In the table, “mm” is generally used as the unit of focal length f, radius of curvature r, surface interval d, and other lengths. However, since the optical system can obtain the same optical performance even when proportionally enlarged or proportionally reduced, the unit is not limited to “mm”, and other appropriate units can be used.

  The description of the above table is the same in other examples, and the description thereof is omitted.

(First embodiment)
A first embodiment will be described with reference to FIGS. 1 and 2 and Table 1. FIG. FIG. 1 is a cross-sectional configuration diagram of a zoom lens according to Example 1. (W) shows a wide-angle end state, (M) shows an intermediate focal length state, and (T) shows a telephoto end state. In addition, the code | symbol which shows the lens used for the following description is described only in a wide angle end state (W), and description is abbreviate | omitted about another state. The same applies to other embodiments.

  As shown in FIG. 1, the zoom lens according to the first example includes a first lens group G1 having a positive refractive power and a second lens having a negative refractive power, which are arranged in order from the object side along the optical axis. It has a lens group G2, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. Then, during zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group G1 and the second lens group increases, and the distance between the second lens group G2 and the third lens group G3 decreases. The first lens group G1 and the third lens group G3 are arranged so that 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. The fifth lens group G5 is moved in the object direction, and the second lens group G2 and the fourth lens group G4 are moved. In the zoom lens according to the present embodiment, focusing on an object at a short distance from a long distance is performed by extending the second lens group G2 in the object direction.

  The first lens group G1 includes, in order from the object side, a cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12, and a positive meniscus lens L13 having a convex surface facing the object side. Have.

  The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a biconcave negative lens L24. The negative meniscus lens L21 located closest to the object side in the second lens group G2 is an aspheric lens having an aspheric surface on the object side lens surface.

  The third lens group G3 includes a biconvex positive lens L31 arranged in order from the object side, a cemented lens of a biconvex positive lens L32 and a negative meniscus lens L33 having a concave surface facing the object side, and a convex surface facing the object side. And a cemented lens of a negative meniscus lens L34 and a biconvex positive lens L35.

  The fourth lens group G4 includes, in order from the object side, a cemented lens of a biconcave negative lens L41 and a positive meniscus lens L42 having a convex surface facing the object side, and a negative meniscus lens L43 having a concave surface facing the object side. Have. The negative meniscus lens L43 located closest to the image plane I of the fourth lens group G4 is an aspheric lens having an aspheric lens surface on the object side.

  The fifth lens group G5 is composed of a biconvex positive lens L51, a cemented lens composed of a biconvex positive lens L52 and a negative meniscus lens L53 having a concave surface facing the object side, and a concave surface facing the object side. Negative meniscus lens L54. The negative meniscus lens L53 located closest to the image plane I in the fifth lens group G5 is an aspheric lens having an aspheric lens surface on the object side.

  The aperture stop S is disposed between the second lens group G2 and the third lens group G3, and moves together with the third lens group G3 upon zooming from the wide-angle end state to the telephoto end state.

  The fixed stop SP is disposed in the fourth lens group G4 and moves together with the fourth lens group G4 upon zooming from the wide-angle end state to the telephoto end state.

  Table 1 below shows values of various specifications of the zoom lens according to the first example. The surface numbers 1 to 36 in Table 1 correspond to the surfaces 1 to 36 shown in FIG.

(Table 1)
[Overall specifications]
Wide-angle end state Intermediate focal length state Telephoto end state f 28.8 to 100.1 to 292.0
FNO 3.6 to 5.4 to 5.8
2ω 76.6 to 23.3 to 8.2
Y 21.6-21.6-21.6
TL 150.021-204.745-231.787
Bf 38.421-66.084-79.260
[Lens data]
Surface number r d nd νd
1 155.3288 2.000 1.90366 31.27
2 74.7206 9.300 1.49782 82.56
3 -353.7135 0.100
4 65.5112 6.500 1.59319 67.87
5 341.1746 D5
* 6 97.6064 1.350 1.76546 46.73
7 18.1823 6.300
8 -51.0828 1.000 1.80400 46.58
9 51.0828 0.100
10 33.1197 4.600 1.92286 20.5
11 -116.2891 1.200
12 -37.8145 1.000 1.80400 46.58
13 900.9344 D13
14 Aperture stop S 0.500
15 48.4611 3.300 1.75500 52.29
16 -84.9321 0.100
17 31.3999 5.100 1.49782 82.56
18 -46.3180 1.000 1.84666 23.78
19 -2005.953 0.200
20 35.0089 1.200 1.83481 42.72
21 14.5043 6.600 1.51823 58.89
22 -90.4178 D22
23 -68.2959 1.000 1.77250 49.61
24 15.2089 2.900 1.85026 32.34
25 50.4199 1.785
26 Fixed aperture SP 3.200
* 27 -22.2821 0.200 1.55389 38.09
28 -22.2821 1.200 1.72916 54.66
29 -45.6998 D29
30 78.3508 5.700 1.51823 58.89
31 -25.3521 0.300
32 49.9836 6.200 1.51742 52.32
33 -30.6962 1.100 1.90366 31.27
34 -54.0563 1.950
* 35 -27.3827 1.300 1.8208 42.64
36 -82.9152 Bf
[Aspherical data]
6th surface κ = -12.2131, A4 = 6.17E-07, A6 = -6.68E-09, A8 = -7.12E-12,
A10 = 7.97E-14, A12 = -1.54E-16
27th surface κ = -0.1607, A4 = 2.05E-06, A6 = 5.80E-08, A8 = 9.38E-12
35th surface κ = 1.0000, A4 = -1.05E-05, A6 = -2.59E-09, A8 = 5.74E-12, A10 = 3.01E-14
[Variable surface interval data]
Wide-angle end state Intermediate focal length state Telephoto end state
D5 2.736 37.836 63.419
D13 31.152 14.114 2.396
D22 2.344 5.937 7.127
D29 6.082 2.489 1.300
[Lens group data]
Group number Group first surface Group focal length G1 1 109.383
G2 6 -17.376
G3 14 25.282
G4 23 -24.060
G5 30 39.999
[Conditional expression values]
Conditional expression (1) nd2 = 1.92286 (lens L23)
Conditional expression (2) (− f2) / (− f4) = 0.72
Conditional expression (3) f3 / (− f4) = 1.05
Conditional expression (4) f5 / (− f4) = 1.66

  From the table of specifications shown in Table 1, it can be seen that the zoom lens according to Example 1 satisfies all the conditional expressions (1) to (4).

  2A and 2B are graphs showing various aberrations of the zoom lens according to Example 1. FIG. 2A is a diagram showing various aberrations in the infinite focus state in the wide-angle end state, and FIG. 2B is infinite focus in the intermediate focal length state. FIG. 6C is a diagram illustrating various aberrations in the infinitely focused state in the telephoto end state. In each aberration diagram, FNO represents an F number, and Y represents an image height (unit: mm). The spherical aberration diagram shows the F-number value corresponding to the maximum aperture, the astigmatism diagram and the distortion diagram show the maximum image height, and the coma diagram shows the value of each image height. Further, d indicates various aberrations with respect to the d-line (wavelength 587.6 nm), g indicates various aberrations with respect to the g-line (wavelength 435.8 nm), and those not described indicate various aberrations with respect to the d-line. In the astigmatism diagram, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane. The explanation of the above aberration diagrams is the same in the other examples, and the explanation is omitted.

  As is apparent from the respective aberration diagrams, in the first example, it is understood that various aberrations are well corrected and excellent imaging performance is obtained in each focal length state from the wide-angle end state to the telephoto end state.

(Second embodiment)
The second embodiment will be described with reference to FIGS. 3 and 4 and Table 2. FIG. FIG. 3 is a cross-sectional configuration diagram of a zoom lens according to Example 2, where (W) shows a wide-angle end state, (M) shows an intermediate focal length state, and (T) shows a telephoto end state. As shown in FIG. 3, the zoom lens according to the second embodiment includes a first lens group G1 having a positive refractive power and a second lens having a negative refractive power, which are arranged in order from the object side along the optical axis. It has a lens group G2, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. Then, during zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group G1 and the second lens group increases, and the distance between the second lens group G2 and the third lens group G3 decreases. The first lens group G1 and the third lens group G3 are arranged so that 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. The fifth lens group G5 is moved in the object direction, and the second lens group G2 and the fourth lens group G4 are moved. In the zoom lens according to the present embodiment, focusing on an object at a short distance from a long distance is performed by extending the second lens group G2 in the object direction.

  The first lens group G1 includes, in order from the object side, a cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12, and a positive meniscus lens L13 having a convex surface facing the object side. Have.

  The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a biconcave negative lens L24. Note that the negative meniscus lens L21 located closest to the object side in the second lens group G2 is an aspheric lens having an aspheric lens surface on the object side.

  The third lens group G3 includes a biconvex positive lens L31 arranged in order from the object side, a cemented lens of a biconvex positive lens L32 and a negative meniscus lens L33 having a concave surface facing the object side, and a convex surface facing the object side. And a cemented lens of a negative meniscus lens L34 and a biconvex positive lens L35.

  The fourth lens group G4 includes, in order from the object side, a cemented lens of a biconcave negative lens L41 and a positive meniscus lens L42 having a convex surface facing the object side, and a negative meniscus lens L43 having a concave surface facing the object side. Have. The negative meniscus lens L43 located closest to the image plane I of the fourth lens group G4 is an aspheric lens having an aspheric lens surface on the object side.

  The fifth lens group G5 is composed of a biconvex positive lens L51, a cemented lens composed of a biconvex positive lens L52 and a negative meniscus lens L53 having a concave surface facing the object side, and a concave surface facing the object side. Negative meniscus lens L54. The negative meniscus lens L53 located closest to the image plane I in the fifth lens group G5 is an aspheric lens having an aspheric lens surface on the object side.

  The aperture stop S is disposed between the second lens group G2 and the third lens group G3, and moves together with the third lens group G3 upon zooming from the wide-angle end state to the telephoto end state.

  The fixed stop SP is disposed in the fourth lens group G4 and moves together with the fourth lens group G4 upon zooming from the wide-angle end state to the telephoto end state.

  Table 2 below shows values of various specifications of the zoom lens according to the second example. The surface numbers 1 to 36 in Table 2 correspond to the surfaces 1 to 36 shown in FIG.

(Table 2)
[Overall specifications]
Wide-angle end state Intermediate focal length state Telephoto end state f 28.8 to 100.0 to 292.0
FNO 3.6 to 5.4 to 5.8
2ω 76.6 to 23.3 to 8.2
Y 21.6-21.6-21.6
TL 159.022-204.828-231.791
Bf 38.423 to 66.167 to 79.264
[Lens data]
Surface number r d nd νd
1 138.4891 2.000 1.90366 31.27
2 73.2156 9.300 1.49782 82.56
3 -502.1696 0.100
4 66.3869 6.500 1.59319 67.87
5 341.1746 D5
* 6 139.6256 1.350 1.83481 42.72
7 18.7119 6.300
8 -41.9189 1.000 1.80400 46.58
9 47.2984 0.100
10 34.7718 4.600 2.00069 25.46
11 -43.3923 1.200
12 -27.1478 1.000 1.80400 46.58
13 900.9344 D13
14 Aperture stop S 0.500
15 69.5335 3.300 1.61800 63.38
16 -82.8727 0.100
17 27.1628 5.100 1.49782 82.56
18 -61.0391 1.000 1.84666 23.78
19 -424.9302 0.200
20 32.6799 1.200 1.83481 42.72
21 14.4261 6.600 1.51823 58.89
22 -90.4178 D22
23 -143.6229 1.000 1.77250 49.61
24 16.3837 2.900 1.85026 32.34
25 50.4199 1.785
26 Fixed aperture SP 3.200
* 27 -20.8423 0.200 1.55389 38.09
28 -20.8423 1.200 1.72916 54.66
29 -45.6998 D29
30 58.7089 5.700 1.51823 58.89
31 -25.6925 0.300
32 81.2720 6.200 1.51742 52.32
33 -24.4636 1.100 1.90366 31.27
34 -41.9090 1.950
* 35 -25.4300 1.300 1.8208 42.64
36 -82.9152 Bf
[Aspherical data]
6th surface κ = -29.4063, A4 = 3.62E-06, A6 = -1.78E-08, A8 = 9.64E-13,
A10 = -2.71E-13, A12 = 4.44E-16
27th surface κ = -0.02999, A4 = -1.21E-06, A6 = 7.74E-08, A8 = -3.75E-11,
35th surface κ = 1.000, A4 = -1.04E-05, A6 = -2.62E-09, A8 = 1.68E-10, A10 = -4.66E-13
[Variable surface interval data]
Wide-angle end state Intermediate focal length state Telephoto end state
D5 2.736 37.836 63.419
D13 31.152 14.114 2.396
D22 2.344 5.937 7.127
D29 6.082 2.489 1.300
[Lens group data]
Group number Group first surface Group focal length G1 1 108.988
G2 6 -17.282
G3 14 25.991
G4 23 -26.556
G5 30 44.433
[Conditional expression values]
Conditional expression (1) nd2 = 2.00069 (lens L23)
Conditional expression (2) (− f2) / (− f4) = 0.65
Conditional expression (3) f3 / (− f4) = 0.98
Conditional expression (4) f5 / (− f4) = 1.67

  From the table of specifications shown in Table 2, it can be seen that the zoom lens according to Example 2 satisfies all the conditional expressions (1) to (4).

  4A and 4B are graphs showing various aberrations of the zoom lens according to Example 2. FIG. 4A is a diagram showing various aberrations in the infinite focus state in the wide-angle end state, and FIG. 4B is infinite focus in the intermediate focal length state. FIG. 6C is a diagram illustrating various aberrations in the infinitely focused state in the telephoto end state.

  As is apparent from the respective aberration diagrams, in the second embodiment, it is understood that various aberrations are favorably corrected and excellent imaging performance is obtained in each focal length state from the wide-angle end state to the telephoto end state.

(Third embodiment)
A third embodiment will be described with reference to FIGS. 5 and 6 and Table 3. FIG. FIG. 5 is a cross-sectional configuration diagram of a zoom lens according to Example 3. (W) shows a wide-angle end state, (M) shows an intermediate focal length state, and (T) shows a telephoto end state. As shown in FIG. 5, the zoom lens according to the third example includes a first lens group G1 having a positive refractive power and a second lens having a negative refractive power, which are arranged in order from the object side along the optical axis. It has a lens group G2, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. Then, during zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group G1 and the second lens group increases, and the distance between the second lens group G2 and the third lens group G3 decreases. The first lens group G1 and the third lens group G3 are arranged so that 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. The fifth lens group G5 is moved in the object direction, and the second lens group G2 and the fourth lens group G4 are moved. In the zoom lens according to the present embodiment, focusing on an object at a short distance from a long distance is performed by extending the second lens group G2 in the object direction.

  The first lens group G1 has a cemented lens composed of a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side, and a convex surface facing the object side. And a positive meniscus lens L13.

  The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a biconcave negative lens L24. Note that the negative meniscus lens L21 located closest to the object side in the second lens group G2 is an aspheric lens having an aspheric lens surface on the object side.

  The third lens group G3 includes, in order from the object side, a cemented lens of a negative meniscus lens L31 having a convex surface directed toward the object side and a biconvex positive lens L32, and a biconvex positive lens L33.

  The fourth lens group G4 includes a biconcave negative lens L41 arranged in order from the object side and a cemented lens of a positive meniscus lens L42 having a convex surface directed toward the object side.

  The fifth lens group G5 includes a biconvex positive lens L51 and a cemented lens of a biconvex positive lens L52 and a negative meniscus lens L53 having a concave surface facing the object side, which are arranged in order from the object side.

  The aperture stop S is disposed between the second lens group G2 and the third lens group G3, and moves together with the third lens group G3 upon zooming from the wide-angle end state to the telephoto end state.

  The fixed stop SP is disposed between the fourth lens group G4 and the fifth lens group G5, and moves together with the fourth lens group G4 upon zooming from the wide-angle end state to the telephoto end state.

  Table 3 below shows values of various specifications of the zoom lens according to the third example. The surface numbers 1 to 29 in Table 3 correspond to the surfaces 1 to 29 shown in FIG.

(Table 3)
[Overall specifications]
Wide-angle end state Intermediate focal length state Telephoto end state f 18.8 to 56.2 to 96.5
FNO 3.6 to 5.1 to 5.7
2ω 79.1 to 28.4 to 16.8
Y 14.75-14.75-14.75
TL 132.130-156.884-170.568
Bf 37.064-53.299-57.641
[Lens data]
Surface number r d nd νd
1 118.6191 1.800 1.80518 25.43
2 56.3461 6.6500 1.60311 60.68
3 750.6281 0.100
4 61.3129 4.400 1.69680 55.52
5 245.7903 D5
* 6 161.2961 0.200 1.55389 38.09
7 135.3684 1.200 1.80610 40.94
8 14.0958 6.050
9 -74.5352 1.000 1.80610 40.94
10 25.6583 0.8500
11 23.2945 5.300 1.92286 20.50
12 -1195.1730 0.200
13 -255.4416 1.000 1.80610 40.94
14 104.5657 D14
15 Aperture stop S 0.400
16 26.8351 1.200 1.75520 27.51
17 14.7975 4.400 1.49782 82.56
18 -58.1727 0.100
19 33.8968 2.500 1.61800 63.38
20 -99.7862 D20
21 -47.7287 0.800 1.72916 54.66
22 13.4712 2.400 1.85026 32.35
23 40.8366 3.400
24 Fixed aperture SP D24
25 3123.7337 3.500 1.51680 64.12
26 -22.7710 0.400
27 67.0385 6.700 1.48749 70.45
28 -16.1162 1.200 1.85026 32.35
29 -63.5268 Bf
[Aspherical data]
6th surface κ = 87.2163, A4 = 1.31E-06, A6 =-1.32E-08, A8 = 3.49E-12, A10 = -9.99E-14
[Variable surface interval data]
Wide-angle end state Intermediate focal length state Telephoto end state
D5 1.925 27.504 41.484
D14 24.942 7.881 3.244
D20 2.034 7.049 8.772
D24 10.416 5.401 3.678
[Lens group data]
Group number Group first surface Group focal length G1 1 91.792
G2 6 -15.033
G3 15 23.831
G4 21 -36.549
G5 25 45.130
[Conditional expression values]
Conditional expression (1) nd2 = 1.92286 (L23)
Conditional expression (2) (− f2) / (− f4) = 0.41
Conditional expression (3) f3 / (− f4) = 0.65
Conditional expression (4) f5 / (− f4) = 1.23

  From the table of specifications shown in Table 3, it can be seen that the zoom lens according to Example 3 satisfies all the conditional expressions (1) to (4).

  6A and 6B are graphs showing various aberrations of the zoom lens according to Example 3. FIG. 6A is a diagram showing various aberrations in the infinity in-focus state at the wide-angle end state, and FIG. 6B is infinity in-focus in the intermediate focal length state. FIG. 6C is a diagram illustrating various aberrations in the infinitely focused state in the telephoto end state.

  As is apparent from the respective aberration diagrams, in the third example, it is understood that various aberrations are well corrected and excellent imaging performance is obtained in each focal length state from the wide-angle end state to the telephoto end state.

(Fourth embodiment)
A fourth embodiment will be described with reference to FIGS. 7 and 8 and Table 4. FIG. FIG. 7 is a cross-sectional configuration diagram of a zoom lens according to Example 4. (W) shows a wide-angle end state, (M) shows an intermediate focal length state, and (T) shows a telephoto end state. As shown in FIG. 7, the zoom lens according to the fourth example includes a first lens group G1 having a positive refractive power and a second lens having a negative refractive power, which are arranged in order from the object side along the optical axis. It has a lens group G2, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. Then, during zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group G1 and the second lens group increases, and the distance between the second lens group G2 and the third lens group G3 decreases. The first lens group G1 and the third lens group G3 are arranged so that 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. The fifth lens group G5 is moved in the object direction, and the second lens group G2 and the fourth lens group G4 are moved. In the zoom lens according to the present embodiment, focusing on an object at a short distance from a long distance is performed by extending the second lens group G2 in the object direction.

  The first lens group G1 has a cemented lens composed of a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side, and a convex surface facing the object side. And a positive meniscus lens L13.

  The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface facing the object side, a biconcave negative lens L22, a negative meniscus lens L23 having a convex surface facing the object side, and a convex surface facing the object side. And a cemented lens with a positive meniscus lens L24. Note that the negative meniscus lens L21 located closest to the object side in the second lens group G2 is an aspheric lens having an aspheric lens surface on the object side.

  The third lens group G3 includes, in order from the object side, a cemented lens of a negative meniscus lens L31 having a convex surface directed toward the object side and a biconvex positive lens L32, and a biconvex positive lens L33.

  The fourth lens group G4 includes a biconcave negative lens L41 arranged in order from the object side and a cemented lens of a positive meniscus lens L42 having a convex surface directed toward the object side.

  The fifth lens group G5 includes, in order from the object side, a positive meniscus lens L51 having a concave surface facing the object side, and a cemented lens of a biconvex positive lens L52 and a negative meniscus lens L53 having a concave surface facing the object side. Have.

  The aperture stop S is disposed between the second lens group G2 and the third lens group G3, and moves together with the third lens group G3 upon zooming from the wide-angle end state to the telephoto end state.

  The fixed stop SP is disposed between the fourth lens group G4 and the fifth lens group G5, and moves together with the fourth lens group G4 upon zooming from the wide-angle end state to the telephoto end state.

  Table 4 below shows values of various specifications of the zoom lens according to the fourth example. The surface numbers 1 to 28 in Table 4 correspond to the surfaces 1 to 28 shown in FIG.

(Table 4)
[Overall specifications]
Wide-angle end state Intermediate focal length state Telephoto end state f 18.8 to 56.2 to 96.5
FNO 3.6 to 5.1 to 5.7
2ω 79.1 to 28.4 to 16.8
Y 14.75-14.75-14.75
TL 132.130-156.884-170.568
Bf 37.064-53.299-57.641
[Lens data]
Surface number r d nd νd
1 121.9241 1.800 1.80518 25.43
2 57.2644 6.650 1.60311 60.68
3 971.4574 0.100
4 61.1719 4.400 1.69680 55.52
5 238.3757 D5
* 6 161.2961 0.200 1.55389 38.09
7 135.3684 1.200 1.80610 40.94
8 14.0958 6.050
9 -106.2115 1.000 1.80610 40.94
10 29.4458 1.450
11 24.8406 1.200 1.80610 40.94
12 20.6610 4.700 1.94595 17.98
13 57.3358 D13
14 Aperture stop S 0.400
15 27.0045 1.200 1.75520 27.51
16 14.8526 4.400 1.49782 82.56
17 -50.9026 0.100
18 35.0499 2.500 1.61800 63.38
19 -109.4035 D19
20 -47.3620 0.800 1.72916 54.66
21 13.5249 2.400 1.85026 32.35
22 41.1461 3.400
23 Fixed aperture SP D23
24 -2162.4970 3.500 1.51680 64.12
25 -22.4246 0.400
26 65.3027 6.700 1.48749 70.45
27 -16.2360 1.200 1.85026 32.35
28 -65.2730 Bf
[Aspherical data]
6th surface κ = 91.1992, A4 = 1.35E-07, A6 = -1.22E-08, A8 = 2.32E-11, A10 = -1.80E-13
[Variable surface interval data]
Wide-angle end state Intermediate focal length state Telephoto end state
D5 1.925 27.504 41.483
D14 24.942 7.881 3.244
D20 2.034 7.049 8.772
D24 10.416 5.401 3.678
[Lens group data]
Group number Group first surface Group focal length G1 1 91.792
G2 6 -15.033
G3 15 23.831
G4 20 -36.549
G5 24 45.130
[Conditional expression values]
Conditional expression (1) nd2 = 1.94595 (Lens L24)
Conditional expression (2) (− f2) / (− f4) = 0.41
Conditional expression (3) f3 / (− f4) = 0.65
Conditional expression (4) f5 / (− f4) = 1.23

  From the table of specifications shown in Table 4, it can be seen that the zoom lens according to Example 4 satisfies all the conditional expressions (1) to (4).

  8A and 8B are graphs showing various aberrations of the zoom lens according to Example 4. FIG. 8A is a diagram showing various aberrations in the infinite focus state in the wide-angle end state, and FIG. 8B is in focus at infinity in the intermediate focal length state. FIG. 6C is a diagram illustrating various aberrations in the infinitely focused state in the telephoto end state.

  As is apparent from the respective aberration diagrams, in the fourth example, it is understood that various aberrations are well corrected and excellent imaging performance is obtained in each focal length state from the wide-angle end state to the telephoto end state.

(5th Example)
The fifth embodiment will be described with reference to FIGS. 9 and 10 and Table 5. FIG. FIG. 9 is a cross-sectional configuration diagram of a zoom lens according to Example 5. (W) shows a wide-angle end state, (M) shows an intermediate focal length state, and (T) shows a telephoto end state. As shown in FIG. 9, the zoom lens according to Example 5 includes a first lens group G1 having a positive refractive power and a second lens having a negative refractive power arranged in order from the object side along the optical axis. It has a lens group G2, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. Then, during zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group G1 and the second lens group increases, and the distance between the second lens group G2 and the third lens group G3 decreases. The first lens group G1 and the third lens group G3 are arranged so that 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. The fifth lens group G5 is moved in the object direction, and the second lens group G2 and the fourth lens group G4 are moved. In the zoom lens according to the present embodiment, focusing on an object at a short distance from a long distance is performed by extending the second lens group G2 in the object direction.

  The first lens group G1 has a cemented lens composed of a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side, and a convex surface facing the object side. And a positive meniscus lens L13.

  The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface facing the object side, a biconcave negative lens L22, a positive meniscus lens L23 having a convex surface facing the object side, and an object side. A negative meniscus lens L24 having a concave surface. Note that the negative meniscus lens L21 located closest to the object side in the second lens group G2 is an aspheric lens having an aspheric lens surface on the object side.

  The third lens group G3 includes a biconvex positive lens L31 arranged in order from the object side, a cemented lens of a negative meniscus lens L32 having a convex surface facing the object side, and a biconvex positive lens L33, and a biconvex positive lens L34. And a cemented lens.

  The fourth lens group G4 includes, in order from the object side, a cemented lens of a positive meniscus lens L41 having a concave surface directed toward the object side and a biconcave negative lens L42, and a negative lens L43 having a concave surface directed toward the object side. . In the fourth lens group G4, the biconcave negative lens L42 constituting the cemented lens located closest to the object side is an aspheric lens having an aspheric surface on the image side.

  The fifth lens group G5 includes, in order from the object side, a biconvex positive lens L51, a cemented lens of a positive meniscus lens L52 having a concave surface facing the object side, and a negative meniscus lens L53 having a concave surface facing the object side. Have. The biconvex positive lens L51 located on the most object side of the fifth lens group G5 is an aspheric lens in which both the object side lens surface and the image side lens surface are aspherical.

  The aperture stop S is disposed in 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.

  Table 5 below lists values of various specifications of the zoom lens according to Example 5. In addition, the surface numbers 1-31 in Table 5 respond | correspond to the surfaces 1-31 shown in FIG.

(Table 5)
[Overall specifications]
Wide-angle end state Intermediate focal length state Telephoto end state f 24.6 to 50.0 to 117.0
FNO 4.1-4.1-4.1
2ω 85.4 to 45.2 to 20.4
Y 21.6-21.6-21.6
TL 149.549-163.459-192.357
Bf 40.381-50.515-67.752
[Lens data]
Surface number r d nd νd
1 145.9142 1.500 1.84666 23.75
2 64.4133 7.700 1.59319 67.87
3 959.4547 0.100
4 54.0488 5.100 1.75500 52.29
5 133.5726 D5
* 6 118.7745 1.350 1.79668 45.34
* 7 14.6412 7.200
8 -85.9591 1.000 1.77250 49.61
9 43.2968 0.100
10 31.5833 3.600 1.94595 17.98
11 304.1231 2.300
12 -25.7680 1.000 1.77250 49.61
13 -36.7285 D13
14 70.8944 2.300 1.75500 52.29
15 -209.4849 1.400
16 Aperture stop S 0.500
17 28.3582 1.400 1.84666 23.75
18 17.9719 7.650 1.48749 70.45
19 -62.1636 0.100
20 48.5750 2.600 1.59319 67.87
21 -527.3854 D21
22 -56.6852 3.350 1.85026 32.33
23 -19.2954 1.000 1.75500 52.29
* 24 69.4557 3.300
25 -29.8749 1.000 1.81600 46.63
26 -69.2476 D26
* 27 55.7040 7.400 1.58913 61.18
* 28 -21.4359 0.100
29 -114.2550 5.400 1.48749 70.45
30 -21.2096 1.500 1.90366 31.31
31 -80.3390 Bf
[Aspherical data]
6th surface κ = 1.0000, A4 = 3.76E-06, A6 = -4.33E-08, A8 = 1.63E-10, A10 = -1.92E-13
7th surface κ = 1.0000, A4 = -5.25E-06, A6 = -9.56E-08, A8 = -1.38E-10, A10 = -4.65E-13
24th surface κ = 1.0000, A4 = -2.43E-06, A6 = 1.40E-08, A8 = -4.51E-11
27th surface κ = 1.0000, A4 = 1.17E-05, A6 = 1.47E-08, A8 = -7.64E-11, A10 = -8.47E-15
28th surface κ = 1.000, A4 = 1.03E-05, A6 = 1.08E-08, A8 = -3.25E-12, A10 = -1.56E-13
[Variable surface interval data]
Wide-angle end state Intermediate focal length state Telephoto end state
D5 2.659 22.048 42.526
D13 21.623 10.014 1.198
D21 2.756 6.486 9.368
D26 8.194 4.464 1.582
[Lens group data]
Group number Group first surface Group focal length G1 1 102.837
G2 6 -16.660
G3 14 24.284
G4 20 -26.343
G5 34 39.104
[Conditional expression values]
Conditional expression (1) nd2 = 1.94595 (lens L23)
Conditional expression (2) (− f2) / (− f4) = 0.63
Conditional expression (3) f3 / (− f4) = 0.92
Conditional expression (4) f5 / (− f4) = 1.48

  From the table of specifications shown in Table 5, it can be seen that the zoom lens according to Example 5 satisfies all the conditional expressions (1) to (4).

  10A and 10B are graphs showing various aberrations of the zoom lens according to Example 5. FIG. 10A is a diagram showing various aberrations in the infinite focus state at the wide-angle end state, and FIG. 10B is an infinite focus in the intermediate focal length state. FIG. 6C is a diagram illustrating various aberrations in the infinitely focused state in the telephoto end state.

  As is apparent from each aberration diagram, in the fifth example, it is understood that various aberrations are well corrected and excellent imaging performance is obtained in each focal length state from the wide-angle end state to the telephoto end state.

  In the above-described embodiment, the following description can be appropriately adopted as long as the optical performance is not impaired.

  In the above embodiment, the five-group configuration is shown, but the present invention can also be applied to other group configurations such as six groups. Further, a configuration in which a lens or a lens group is added closest to the object side, or a configuration in which a lens or a lens group is added closest to the image side may be used. The lens group refers to a portion having at least one lens separated by an air interval that changes during zooming.

  In addition, a single lens group, 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. 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 is a focusing lens group.

  In addition, the lens group or the partial lens group is moved so as to have a component in a direction perpendicular to the optical axis, or is rotated (swayed) in the in-plane direction including the optical axis to cause image blur caused by camera shake. A vibration-proof lens group to be corrected may be used. In particular, it is preferable that at least a part of the third lens group G3 or at least a part of the fourth lens group G4 is an anti-vibration lens group.

  Further, the lens surface may be formed as a spherical surface, a flat surface, or an aspherical 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 can be prevented. In addition, even when the image plane is deviated, it is preferable because there is little deterioration in drawing performance. If the lens is aspherical, the aspherical surface is an aspherical surface formed by grinding, a glass mold aspherical surface formed of glass with an aspherical shape, or a composite aspherical surface formed of resin on the glass surface with an aspherical shape. Any aspherical surface may be used. The lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

  The aperture stop S is preferably arranged in the vicinity of the third lens group G3. However, the role of the aperture stop may be substituted by a lens frame without providing a member as an aperture stop.

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

  The zoom lens (variable magnification optical system) of the present embodiment has a magnification ratio of 4 to 20 times, more preferably 4.5 to 15 times.

  In the zoom lens (variable magnification optical system) of the present embodiment, it is preferable that the first lens group G1 has two positive lens components.

  In the zoom lens (variable magnification optical system) 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.

  In the zoom lens (variable magnification optical system) of the present embodiment, it is preferable that the third lens group G3 has three positive lens components.

  In the zoom lens (variable magnification optical system) of the present embodiment, it is preferable that the fourth lens group G4 has two negative lens components.

  In the zoom lens (variable magnification optical system) of the present embodiment, it is preferable that the fifth lens group G5 has two positive lens components.

  In addition, in order to make this invention intelligible, although demonstrated with the component requirement of embodiment, it cannot be overemphasized that this invention is not limited to this.

G1 1st lens group G2 2nd lens group G3 3rd lens group G4 4th lens group G5 5th lens group S Aperture stop SP Fixed stop I Image surface CAM Digital single lens reflex camera (optical equipment)

Claims (16)

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 first lens group having a negative refractive power, arranged in order from the object side. The four lens groups and the fifth lens group having a positive refractive power substantially consist of five lens groups ,
Angle end state to the telephoto end state, so that the distance between the lens units are changed, the fifth lens group and the third lens group and the third lens group moves toward the object side, the first The second lens group and the fourth lens group move,
The second lens group includes at least three lenses having a negative refractive power and at least one lens having a positive refractive power.
When the refractive index of the d-line (wavelength 587.56 nm) of the positive lens constituting the second lens group is nd2, the following formula 1.87 <nd2
A zoom lens that satisfies the following conditions. 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 first lens group having a negative refractive power, arranged in order from the object side. The four lens groups and the fifth lens group having a positive refractive power substantially consist of five lens groups,
When zooming from the wide-angle end state to the telephoto end state, the distance between the lens groups changes,
The second lens group includes at least three lenses having a negative refractive power and at least one lens having a positive refractive power.
The refractive index of the d-line (wavelength 587.56 nm) of the positive lens constituting the second lens group is nd2, the focal length of the fourth lens group is f4, and the focal length of the fifth lens group is f5. When
  1.87 <nd2
0.80 <f5 / (− f4) <3.50
A zoom lens that satisfies the following conditions. 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 first lens group having a negative refractive power, arranged in order from the object side. The four lens groups and the fifth lens group having a positive refractive power substantially consist of five lens groups ,
When zooming from the wide-angle end state to the telephoto end state, the distance between the lens groups changes,
The second lens group includes at least three lenses having a negative refractive power and at least one lens having a positive refractive power.
The refractive index of the d-line (wavelength 587.56 nm) of the positive lens constituting the second lens group is nd2, the focal length of the third lens group is f3, and the focal length of the fourth lens group is f4. When
1.87 <nd2
0.60 <f3 / (− f4) <1.20
A zoom lens that satisfies the following conditions. 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 first lens group having a negative refractive power, arranged in order from the object side. 4 lens group and a fifth lens group having positive refractive power,
Upon zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group decreases, The distance between the third lens group and the fourth lens group is increased, and the distance between the fourth lens group and the fifth lens group is decreased, so that the first lens group, the third lens group, and the The fifth lens group moves to the object side, the second lens group and the fourth lens group move,
The second lens group includes at least three lenses having a negative refractive power and at least one lens having a positive refractive power.
When the refractive index of the d line (wavelength 587.56 nm) of the positive lens constituting the second lens group is nd2, the following formula
1.87 <nd2
A zoom lens that satisfies the following conditions. During zooming from the wide-angle end state to the telephoto end state, the first lens group, the third lens group, and the fifth lens group move toward the object side, and the second lens group and the fourth lens group move. The zoom lens according to claim 2 , wherein: When the focal length of the fourth lens group is f4 and the focal length of the fifth lens group is f5, the following expression 0.80 <f5 / (− f4) <3.50
The zoom lens according to claim 4 , wherein the following condition is satisfied. Upon zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group decreases, The zoom lens according to claim 2 , wherein the distance between the third lens group and the fourth lens group is increased, and the distance between the fourth lens group and the fifth lens group is decreased. 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 0.50 <f3 / (− f4) <1.20
The zoom lens according to claim 1, wherein the following condition is satisfied. When the focal length of the second lens group is f2 and the focal length of the fourth lens group is f4, the following expression 0.30 <(− f2) / (− f4) <1.50
The zoom lens according to any one of claims 1 to 8, characterized by satisfying the condition. The second lens group includes a lens having negative refractive power, a lens having negative refractive power, a lens having positive refractive power, and a lens having negative refractive power, which are arranged in order from the object side. the zoom lens according to any one of claims 1 to 9, characterized in that it has. The second lens group, the zoom lens according to any one of claims 1 to 10, characterized in that at least one aspherical. At least partial lens group in the fourth lens group, the zoom lens according to any one of claims 1 to 11, characterized in that movement to have a component perpendicular to the optical axis. The zoom lens according to any one of claims 1 to 12 , wherein at least a part of the third lens group moves so as to have a component in a direction perpendicular to the optical axis. Infinity focusing from a far object to a close object, zoom according to any one of claims 1 to 13, wherein performing at least a portion of said second lens group is moved in the optical axis direction lens. An optical apparatus characterized by having a zoom lens according to any one of claims 1-14. 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 first lens group having a negative refractive power, arranged in order from the object side. A method of manufacturing a zoom lens comprising substantially four lens groups by four lens groups and a fifth lens group having a positive refractive power,
Angle end state to the telephoto end state, so that the distance between the lens units are changed, the fifth lens group and the third lens group and the third lens group moves toward the object side, the first The second lens group and the fourth lens group move,
The second lens group includes at least three lenses having a negative refractive power and at least one lens having a positive refractive power.
When the refractive index of the d-line (wavelength 587.56 nm) of the positive lens constituting the second lens group is nd2, the following formula 1.87 <nd2
A zoom lens manufacturing method characterized by satisfying the following conditions:

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