JP2019061271A - Variable power optical system and optical apparatus - Google Patents

Abstract

The present invention provides a variable power optical system and an optical apparatus having high optical performance over the entire zoom range.
A first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens group G2 having a positive refractive power are arranged in order from the object side along the optical axis. The first lens group G1 and the second lens group G2 have a lens group G3, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a negative refractive power, and during zooming. , The distance between the second lens group G2 and the third lens group G3, the distance between the third lens group G3 and the fourth lens group G4, and the distance between the fourth lens group G4 and the fifth lens group G5. During zooming, the lens unit closest to the image side is substantially fixed with respect to the image plane I.
[Selected figure] Figure 1

Description

  The present invention relates to a variable magnification optical system and an optical apparatus.

  Heretofore, many variable magnification optical systems suitable for interchangeable lenses for cameras, digital cameras, video cameras and the like have been proposed in which the lens group on the most object side has positive refractive power (for example, Patent Document 1) reference).

JP-A-8-179214

  However, in the conventional variable magnification optical system, there has been a problem that it is difficult to maintain sufficiently high optical performance over the entire zoom range.

  The present invention has been made in view of such problems, and it is an object of the present invention to provide a variable magnification optical system and an optical apparatus having high optical performance over the entire zoom range.

  In order to achieve such an object, the variable magnification optical system according to the first aspect of the present invention comprises a first lens group having positive refractive power and negative refractive power, which are arranged in order from the object side along the optical axis. And has a second lens group having a third refractive power, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a negative refractive power. Distance between the first lens group and the second lens group, distance between the second lens group and the third lens group, distance between the third lens group and the fourth lens group, the fourth lens group The distance between the second lens unit and the fifth lens unit changes, and the lens unit closest to the image side is substantially fixed with respect to the image plane during zooming.

  A variable magnification optical system according to a second aspect of the present invention comprises a first lens group having positive refractive power, a second lens group having negative refractive power, and a second lens group having negative refractive power, which are arranged in order from the object side along the optical axis. A third lens unit having a refractive power, a fourth lens unit having a positive refractive power, a fifth lens unit having a negative refractive power, and a sixth lens unit, and the first lens A distance between a lens group and the second lens group, a distance between the second lens group and the third lens group, a distance between the third lens group and the fourth lens group, a fourth lens group and the fourth lens group The distance between the fifth lens group and the distance between the fifth lens group and the sixth lens group changes, and the lens group closest to the image side is substantially fixed with respect to the image plane during zooming.

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

  According to the present invention, it is possible to provide a variable power optical system and an optical apparatus having high optical performance over the entire zoom range.

(W), (M), and (T) are cross-sectional views in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the first example, respectively. 10A, 10B, and 10C show various aberrations of the variable magnification optical system according to Example 1 at the wide-angle end, at an intermediate focal length, and at an infinite-distance object at the telephoto end, respectively. It is. (A), (b), and (c) are respectively at the time of focusing on a short distance object in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the first embodiment (between object images 2 is a diagram of various aberrations at a distance of 1.00 m). (A), (b), and (c) respectively show image blur correction at the time of focusing on an infinite object in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to Example 1. It is a meridional lateral aberration figure when it did (shift amount of anti-vibration lens group = 0.1 mm). (W), (M), and (T) are cross-sectional views in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively, of the variable magnification optical system according to the second example. 10A, 10B, and 10C show various aberrations of the variable magnification optical system according to the second embodiment at the wide-angle end, at an intermediate focal length, and at an infinite-distance object at the telephoto end, respectively. It is. (A), (b) and (c) show the zoom lens according to the second embodiment at the wide-angle end state, at the intermediate focal length state, and at the telephoto end state when focusing on close-distance objects (between object images 2 is a diagram of various aberrations at a distance of 1.00 m). (A), (b) and (c) respectively show image blur correction at the time of focusing on an infinite object in the wide-angle end state, the intermediate focal length state and the telephoto end state of the variable magnification optical system according to the second embodiment. It is a meridional lateral aberration figure when it did (shift amount of anti-vibration lens group = 0.1 mm). (W), (M), and (T) are cross-sectional views in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively, of the variable magnification optical system according to the third example. 10A, 10B, and 10C show various aberrations of the variable magnification optical system according to the third example at the wide-angle end state, at an intermediate focal length state, and at infinity end in the telephoto end state, respectively. It is. (A), (b) and (c) show the zoom lens according to the third embodiment at the wide-angle end state, at the intermediate focal length state, and at the telephoto end state, respectively 2 is a diagram of various aberrations at a distance of 1.00 m). (A), (b) and (c) respectively show image blur correction at the time of focusing on an infinite object in the wide-angle end state, the intermediate focal length state and the telephoto end state of the variable magnification optical system according to the third embodiment. It is a meridional lateral aberration figure when it did (shift amount of anti-vibration lens group = 0.1 mm). FIG. 2 is a diagram showing a configuration of a camera equipped with the variable magnification optical system according to the present embodiment. It is a figure which shows the outline of the manufacturing method of the variable magnification optical system which concerns on this embodiment.

  Hereinafter, embodiments will be described with reference to the drawings. As shown in FIG. 1, the variable magnification optical system ZL according to this embodiment has a first lens group G1 having positive refractive power and negative refractive power, which are arranged in order from the object side along the optical axis. It has a second lens group G2, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5, and during zooming, the first lens The distance between the group G1 and the second lens group G2, the distance between the second lens group G2 and the third lens group G3, the distance between the third lens group G3 and the fourth lens group G4, the fourth lens group G4 and the fifth The distance from the lens unit G5 is changed. With this configuration, it is possible to realize variable power, and to suppress variations in distortion aberration, astigmatism, and spherical aberration associated with variable power.

  In the variable magnification optical system ZL according to the present embodiment, the lens group closest to the image (corresponding to the fifth lens group G5 in FIG. 1) is substantially fixed to the image plane I at the time of zooming. With this configuration, it is possible to optimize the change in height of the off-axis light beam passing through the lens unit closest to the image at the time of zooming, and to suppress the fluctuation of distortion and astigmatism. In addition, the lens barrel structure constituting the variable magnification optical system ZL according to the present embodiment can be simplified, eccentricity due to manufacturing error or the like can be suppressed, and generation occurs due to eccentricity of the lens group closest to the image. It is possible to suppress decentering comatic aberration and tilting of the peripheral image plane.

  In the variable magnification optical system ZL according to this embodiment, the fourth lens group G4 is configured to have an aperture stop S. According to this configuration, it is possible to suppress variation in astigmatism generated in the fourth lens group G4 during zooming, and high optical performance can be realized.

  It is preferable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (1).

0.480 <f3 / ft <4.000 (1)
However,
ft: focal length of the variable magnification optical system ZL in the telephoto end state,
f3: The focal length of the third lens group G3.

  Conditional expression (1) defines the range of an appropriate focal length of the third lens group G3. By satisfying the conditional expression (1), it is possible to suppress variations in spherical aberration and astigmatism at the time of zooming.

  When the corresponding value of the conditional expression (1) falls below the lower limit value, it becomes difficult to suppress the variation of spherical aberration and astigmatism generated in the third lens group G3 during zooming, and high optical performance can not be realized.

  In order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of the conditional expression (1) to 0.570.

  When the corresponding value of the conditional expression (1) exceeds the upper limit value, the variation of astigmatism generated in the fourth lens group G4 becomes excessive during zooming, and high optical performance can not be realized.

  In order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of the conditional expression (1) to 3.200. In order to further ensure the effect of the present embodiment, it is preferable to set the upper limit value of the conditional expression (1) to 2.400.

  It is preferable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (2).

0.470 <f4 / ft <0.900 (2)
However,
ft: focal length of the variable magnification optical system ZL in the telephoto end state,
f4: The focal length of the fourth lens group G4.

  Conditional expression (2) defines the range of an appropriate focal length of the fourth lens group G4. By satisfying the conditional expression (2), it is possible to suppress the fluctuation of spherical aberration and astigmatism at the time of zooming.

  When the corresponding value of the conditional expression (2) falls below the lower limit value, it becomes difficult to suppress the variation of spherical aberration and astigmatism generated in the fourth lens group G4 at the time of zooming, and high optical performance can not be realized.

  In order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of the conditional expression (2) to 0.530.

  When the corresponding value of the conditional expression (2) exceeds the upper limit value, it is necessary to increase the moving amount of the fourth lens group G4 with respect to the image plane I at the time of zooming in order to secure a predetermined zooming ratio. As a result, the diameter of the on-axis light beam passing through the fourth lens group G4 largely changes, so that the variation of the spherical aberration at the time of zooming becomes excessive, and high optical performance can not be realized.

  In order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of the conditional expression (2) to 0.720.

  In the variable magnification optical system ZL according to the present embodiment, it is preferable that the lens group closest to the image has positive refractive power. With this configuration, the use magnification of the lens unit closest to the image side is smaller than equal magnification, and the lens unit closer to the object side than the lens unit closest to the image (for example, the first lens unit G1 to the fourth lens unit in FIG. 1) It is possible to relatively increase the combined focal length of G4). As a result, it is possible to relatively suppress the influence of decentering coma and the like caused by the decentration of the lenses, which occurs in the lens unit closer to the object than the lens unit closest to the image at the time of manufacture, and high optical performance Can be realized.

  It is preferable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (3).

3.000 <fR / fw <9.500 (3)
However,
fw: focal length of the variable magnification optical system ZL in the wide-angle end state,
fR: focal length of the lens unit closest to the image side.

  The conditional expression (3) defines the range of the appropriate focal length of the lens group closest to the image. By satisfying conditional expression (3), it is possible to suppress fluctuations in astigmatism and distortion at the time of zooming.

  When the corresponding value of the conditional expression (3) falls below the lower limit value, it becomes difficult to suppress fluctuations in astigmatism and distortion generated in the lens unit closest to the image side during zooming, and high optical performance can not be realized.

  In order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of the conditional expression (3) to 4.200.

  When the corresponding value of the conditional expression (3) exceeds the upper limit value, the variation of astigmatism generated in the lens unit closer to the object side than the lens unit closest to the image side is corrected by the lens unit closest to the image side during zooming. It is difficult to achieve high optical performance.

  In order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of the conditional expression (3) to 7.600.

  It is preferable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (4).

0.730 <(− f2) / fw <1.800 (4)
However,
fw: focal length of the variable magnification optical system ZL in the wide-angle end state,
f2: The focal length of the second lens group G2.

  Conditional expression (4) defines an appropriate range of focal length of the second lens group G2. By satisfying the conditional expression (4), it is possible to suppress the variation of spherical aberration and astigmatism at the time of zooming.

  When the corresponding value of the conditional expression (4) falls below the lower limit value, it becomes difficult to suppress the fluctuation of spherical aberration and astigmatism generated in the second lens group G2 during zooming, and high optical performance can not be realized.

  In order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of the conditional expression (4) to 0.900. In order to further ensure the effect of the present embodiment, it is preferable to set the lower limit value of the conditional expression (4) to 1.065.

  When the corresponding value of the conditional expression (4) exceeds the upper limit value, it is necessary to increase the change in the distance between the first lens group G1 and the second lens group G2 during zooming in order to secure a predetermined magnification ratio. is there. As a result, the ratio of the diameter of the axial light beam passing through the first lens group G1 and the second lens group G2 largely changes, so that the variation of the spherical aberration at the time of zooming becomes excessive, and high optical performance can not be realized.

  In order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of the conditional expression (4) to 1.600.

  The variable magnification optical system ZL according to this embodiment satisfies the following conditional expression (5).

−0.100 <(d3t−d3w) / fw <0.330 (5)
However,
fw: focal length of the variable magnification optical system ZL in the wide-angle end state,
d3w: distance on the optical axis from the lens surface of the third lens group G3 closest to the image in the wide-angle end state to the lens surface closest to the object side of the fourth lens group G4;
d3t: distance on the optical axis from the lens surface of the third lens group G3 closest to the image in the telephoto end state to the lens surface closest to the object side of the fourth lens group G4.

  Conditional expression (5) defines an appropriate range of change in the distance between the third lens unit G3 and the fourth lens unit G4 during zooming. By satisfying conditional expression (5), it is possible to suppress the fluctuation of astigmatism at the time of zooming.

  When the corresponding value of the conditional expression (5) falls below the lower limit value, it becomes difficult to suppress fluctuation of astigmatism generated in the third lens group G3 during zooming, and high optical performance can not be realized.

  In order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of the conditional expression (5) to −0.080.

  When the corresponding value in the conditional expression (5) exceeds the upper limit value, the change in height from the optical axis of the off-axis light beam passing through the fourth lens group G4 at the time of zooming becomes large. The fluctuation of the generated astigmatism is excessive, and high optical performance can not be realized.

  In order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit of conditional expression (5) to 0.275.

  In the variable magnification optical system ZL according to the present embodiment, it is preferable that the first lens group G1 move to the object side at the time of zooming from the wide angle end state to the telephoto end state. With this configuration, it is possible to suppress the change in height from the optical axis of the off-axis light flux passing through the first lens group G1 during zooming. As a result, it is possible to suppress the fluctuation of astigmatism generated by the first lens group G1 during zooming.

  In the variable magnification optical system ZL according to this embodiment, it is preferable that the distance between the first lens group G1 and the second lens group G2 be increased at the time of zooming from the wide angle end state to the telephoto end state. With this configuration, the magnification of the second lens group G2 can be multiplied during zooming from the wide-angle end state to the telephoto end state, so the focal lengths of all the lens groups can be made longer. The variation of spherical aberration and astigmatism at the time of doubling can be suppressed.

  In the variable magnification optical system ZL according to this embodiment, it is preferable that the distance between the second lens group G2 and the third lens group G3 be reduced at the time of zooming from the wide angle end state to the telephoto end state. With this configuration, the combined magnification of the third lens group G3 to the fifth lens group G5 can be multiplied during zooming from the wide-angle end state to the telephoto end state, so the focal lengths of all the lens groups are long. It can be configured, and fluctuations of spherical aberration and astigmatism at the time of zooming can be suppressed.

  In the variable magnification optical system ZL according to this embodiment, the aperture stop S is preferably disposed between the third lens group G3 and the fourth lens group G4. This configuration reduces the change in height from off-axis of the off-axis light beam passing through the third lens group G3 and the fourth lens group G4 at the time of zooming, and is generated in the third lens group G3 and the fourth lens group G4. Variation of astigmatism can be suppressed, and high optical performance can be realized.

  In the variable magnification optical system ZL according to the present embodiment, it is preferable that the third lens group G3 move along the optical axis at the time of focusing. With this configuration, the amount of movement at the time of focusing on the telephoto side is suppressed, and the variation in height from the optical axis of the light beam incident on the third lens group G3 which is the focusing lens group at the telephoto side is suppressed. It is possible to suppress the variation of spherical aberration and astigmatism in

  In the variable magnification optical system ZL according to this embodiment, it is preferable that the third lens group G3 move to the image side at the time of focusing from an infinite distance object to a close distance object. With this configuration, focusing can be performed only with the third lens group G3, and fluctuations of spherical aberration and astigmatism at focusing can be suppressed, and high optical performance can be realized.

  According to the variable magnification optical system ZL according to the present embodiment having the above configuration, it is possible to realize a variable magnification optical system having high optical performance over the entire zoom range.

Next, a camera (optical apparatus) provided with the above-described variable magnification optical system ZL will be described with reference to FIG. As shown in FIG. 13, the camera 1 is a lens interchangeable type camera (so-called mirrorless camera) provided with the above-described variable magnification optical system ZL as the photographing lens 2. In the camera 1, light from an object (not shown) from an unshown object is collected by the photographing lens 2, and is taken on the imaging surface of the imaging unit 3 via an OLPF (Optical Low Pass Filter). Form an image of the subject. Then, the subject image is photoelectrically converted by the photoelectric conversion element provided in the imaging unit 3 to generate the image of the subject. This image is displayed on an EVF (Electronic view finder) 4 provided in the camera 1. Thereby, the photographer can observe the subject via the EVF 4. When the photographer presses a release button (not shown), the image of the subject generated by the imaging unit 3 is stored in a memory (not shown). In this way, the photographer can shoot a subject with the main camera 1.

  Here, the variable magnification optical system ZL according to the present embodiment mounted as the photographing lens 2 in the present camera 1 is high over the entire zoom range due to its characteristic lens configuration, as can be seen from each example described later. It has optical performance. Therefore, according to the present camera 1, it is possible to realize an optical apparatus having high optical performance over the entire zoom range.

  Even when the variable magnification optical system ZL described above is mounted on a single lens reflex type camera having a quick return mirror and observing a subject with a finder optical system, the same effect as the camera 1 can be obtained. Further, even when the above-described variable magnification optical system ZL is mounted on a video camera, the same effect as that of the camera 1 can be obtained.

Subsequently, a method of manufacturing the above-described variable magnification optical system ZL will be outlined with reference to FIG. First, in the lens barrel, the first lens group having positive refractive power, the second lens group having negative refractive power, and the positive refractive power are arranged in order from the object side along the optical axis. Each lens is arranged to have a third lens group, a fourth lens group having positive refractive power, and a fifth lens group (step ST10). At this time, at the time of zooming, an interval between the first lens group G1 and the second lens group G2, an interval between the second lens group G2 and the third lens group G3, and a distance between the third lens group G3 and the fourth lens group G4. The respective lenses are arranged such that the interval and the interval between the fourth lens group G4 and the fifth lens group G5 change (step ST20). Further, at the time of zooming, each lens is arranged such that the lens group closest to the image side is substantially fixed to the image plane (step ST30). The fourth lens group G4 is configured to have an aperture stop S (step ST40).

  As an example of the lens arrangement according to the present embodiment, in the variable magnification optical system ZL shown in FIG. 1, as the first lens group G1 having positive refractive power, convex surfaces are sequentially arranged from the object side toward the object side along the optical axis. A cemented lens of a negative meniscus lens L11 with a convex surface facing and a biconvex positive lens L12, and a positive meniscus lens L13 with a convex surface facing the object side are disposed in a lens barrel. As a second lens group G2 having negative refractive power, a negative meniscus lens L21 having a convex surface facing the object side along the optical axis, a biconcave negative lens L22, and a biconvex positive lens. The lens L23 is disposed in the lens barrel. A double convex positive lens L31 is disposed in a lens barrel as a third lens group G3 having positive refractive power. As the fourth lens group G4 having positive refracting power, in order from the object side along the optical axis, the aperture stop S, and a cemented structure of a negative meniscus lens L41 having a convex surface facing the object side and a biconvex positive lens L42. A cemented lens of a biconvex positive lens L43 and a negative meniscus lens L44 having a concave surface facing the object side, and a negative meniscus lens L45 having a convex surface facing the object side are disposed in a lens barrel. As the fifth lens group G5, a positive meniscus lens L51 having a concave surface facing the object side is disposed in a lens barrel.

  According to the method of manufacturing a variable magnification optical system according to the present embodiment, it is possible to manufacture a variable magnification optical system ZL having high optical performance over the entire zoom range.

  Each example according to the present embodiment will be described based on the drawings. Tables 1 to 3 are shown below, and these are tables of each item in the first to third examples.

  Each reference numeral to FIG. 1 according to the first embodiment is used independently for each embodiment in order to avoid complication of explanation due to the increase of the number of digits of the reference code. Therefore, even if the reference numerals in common with the drawings according to the other embodiments are given, they are not necessarily common to the other embodiments.

  In each embodiment, the d-line (wavelength 587.5620 nm) and the g-line (wavelength 435.8350 nm) are selected as calculation targets of the aberration characteristic.

  In [Lens specifications] in the table, the surface number is the order of the optical surface from the object side along the traveling direction of the light, R is the radius of curvature of each optical surface, D is the next optical surface from each optical surface ( Or, the surface distance which is the distance on the optical axis up to the image plane), nd represents the refractive index to the d-line of the material of the optical member, and vd represents the Abbe number based on the d-line of the material of the optical member. The object plane indicates an object plane, (variable) indicates a variable plane distance, the radius of curvature “∞” indicates a plane or an aperture, (aperture stop S) indicates an aperture stop S, and the image plane indicates an image plane I. The refractive index "1.000000" of air is omitted. When the optical surface is aspheric, the surface number is marked with *, and the column of radius of curvature R shows the paraxial radius of curvature.

In [aspheric surface data] in the table, the shape of the aspheric surface shown in [lens specification] is shown by the following equation (a). X (y) is the distance along the optical axis from the tangent plane at the vertex of the aspheric surface to the position on the aspheric surface at height y, R is the radius of curvature (paraxial radius of curvature) of the reference sphere, and κ is Ai represents the ith aspheric coefficient. “E-n” indicates “× 10 ⁻ⁿ ”. For example, 1.234E-05 = 1.234 × 10 ⁻⁵ . The second-order aspheric coefficient A2 is 0, and the description is omitted.

X (y) = (y ² / R) / {1+ (1−κ × y ² / R ² ) ^1/2 } + A ⁴ y ⁴ + A ⁶ y ⁶ + A ⁸ y ⁸ + A ¹⁰ y ¹⁰ + A ¹² y ¹² (a)

  In [various data] in the table, f is the focal length of the entire lens, FNO is the f-number, ω is the half angle of view (unit: "°"), Y is the image height, φ Is the diameter of the aperture stop S, TL is the total optical length (the distance from the first surface to the image plane I at the time of infinity object focusing), BF is the back focus (the most image at the time of infinity object focusing) The distance on the optical axis from the lens surface on the surface side to the image plane I is shown. W indicates the wide-angle end state, M indicates the intermediate focal length state, and T indicates the telephoto end state.

  In [Variable distance data] in the table, the variable distance value Di in each state of the wide angle end state (W), the intermediate focal length state (M) and the telephoto end state (T) at infinity focusing is shown. Di represents a variable interval between the i-th surface and the (i + 1) -th surface.

In [focusing group movement amount at focusing] in the table, in the focusing lens group (third lens group G3) from the infinity in-focus condition to the close-distance in-focus condition (object distance 1.00 m) Indicates the amount of movement. Here, the moving direction of the focusing lens unit is positive at the image side. The shooting distance indicates the distance from the object to the image plane I.

  In [Lens group data] in the table, the starting surface of each lens group and the focal length are shown.

  [Conditional expression corresponding value] in the table indicates values corresponding to the above conditional expressions (1) to (5).

  Hereinafter, in all the specification values, “mm” is generally used unless otherwise specified for the focal length f, radius of curvature R, surface distance D, other lengths, etc. listed, but the optical system is proportionally expanded. Alternatively, since the same optical performance can be obtained by proportional reduction, it is not limited to this. Also, the unit is not limited to "mm", and other appropriate units can be used.

  The description of the tables so far is common to all the embodiments, and the description below is omitted.

(First embodiment)
A first embodiment will be described with reference to FIGS. 1 to 4 and Table 1. The variable magnification optical system ZL (ZL1) according to the first example, as shown in FIG. 1, includes a first lens group G1 having positive refractive power, which is arranged in order from the object side along the optical axis; From a second lens group G2 having a refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a positive refractive power Become. An aperture stop S is provided between the third lens group G3 and the fourth lens group G4, and the aperture stop S constitutes a fourth lens group G4. The fifth lens group G5 is a lens group closest to the image.

  The first lens group G1 has a convex surface facing 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, arranged in order from the object side along the optical axis And a positive meniscus lens L13.

  The second lens group G2 is composed of, in order from the object side along the optical axis, a negative meniscus lens L21 with a convex surface facing the object side, a biconcave negative lens L22, and a biconvex positive lens L23. Become. The negative meniscus lens L21 is a composite aspherical lens of resin and glass in which the lens surface on the object side is aspherical.

The third lens group G3 is composed of a biconvex positive lens L31. The positive lens L31 is
It is a glass mold aspheric lens in which the lens surface on the object side and the image side is aspheric.

  The fourth lens group G4 includes a cemented lens of a negative meniscus lens L41 with a convex surface facing the object side and a biconvex positive lens L42 arranged in order from the object side along the optical axis. The fourth B sub-lens group including a cemented lens of a group G4A, a double convex positive lens L43, and a negative meniscus lens L44 concave on the object side, and a negative meniscus lens L45 convex on the object side It consists of G4B. The negative meniscus lens L44 is a glass mold aspheric lens in which the lens surface on the image side is aspheric.

  The fifth lens group G5 is composed of a positive meniscus lens L51 having a concave surface facing the object side.

  In the variable magnification optical system ZL1 according to the present embodiment, the air gap between the first lens group G1 and the second lens group G2, the second lens group G2 and the third lens during zooming from the wide angle end state to the telephoto end state. The first lens group G1 is such that the air gap with the group G3, the air gap between the third lens group G3 and the fourth lens group G4, and the air gap between the fourth lens group G4 and the fifth lens group G5 change respectively. The fourth lens group G4 moves along the optical axis. The fifth lens group G5 is fixed with respect to the image plane I.

  Specifically, the first to fourth lens groups G1 to G4 move to the object side. The aperture stop S moves integrally with the fourth lens group G4 to the object side.

  Thereby, at the time of zooming, the air gap between the first lens group G1 and the second lens group G2 increases, and the air gap between the second lens group G2 and the third lens group G3 decreases, and the third lens group G3 The air gap between the fourth lens group G4 and the fourth lens group G4 increases, and the air gap between the fourth lens group G4 and the fifth lens group G5 increases. Further, the air gap between the aperture stop S and the third lens group G3 is increased.

  Focusing is performed by moving the third lens group G3 along the optical axis. In detail, at the time of focusing from an infinite distance object to a close distance object, the third lens unit G3 is moved to the image side along the optical axis.

  When an image blur occurs, image blur correction (vibration reduction) on the image plane I is performed by moving the fourth sub lens group G4A as a vibration reduction lens group so as to have a component in a direction perpendicular to the optical axis.

  Table 1 below shows values of respective items in the first embodiment. The surface numbers 1 to 25 in Table 1 correspond to the optical surfaces m1 to m25 shown in FIG.

(Table 1)
[Lens specification]
Face number R D nd d d
Object ∞
1 132.7211 1.6000 1.846660 23.80
2 54.2419 4.5271 1.589130 61.22
3-1401.4921 0.1000
4 36.9475 4.0173 1.696800 55.52
5 200.3945 D5 (variable)
* 6 510.00000 0.0800 1.560930 36.64
7 288.8364 1.0000 1.816000 46.59
8 8.8676 4.8531
9-23.6529 0.9000 1.696800 55.52
10 37.1909 0.7644
11 21.6553 2.6218 1.808090 22.74
12 -149.6082 D12 (variable)
* 13 31.4469 1.4931 1.589130 61.15
* 14-454.8143 D14 (variable)
15 1.7 1.7118 (F-stop)
16 17.8093 0.9000 1.834000 37.18
17 10.8731 2.4554 1.497820 82.57
18-36.9740 1.5005
19 14.0517 2.3992 1.518230 58.82
20 -15.0205 1.0034 1.851350 40.13
* 21-25.0875 0.2985
22 23.6629 2.4328 1.902650 35.73
23 8.6520 D23 (variable)
24-29.9885 2.0872 1.617720 49.81
25-17.6129 BF
Image plane ∞

[Aspheric surface data]
Sixth face == 1.00000
A4 = 1.30134 E-05
A6 = 5.20059E-08
A8 = -1.38176E-09
A10 = 6.06866 E-12
A12 = 0.00000 E + 00

13th surface 面 = 0.3322
A4 = 5.55970 E-05
A6 = 3.96498E-07
A8 = 3.97804E-09
A10 = 0.00000 E + 00
A12 = 0.00000 E + 00

Face 14 κ = 4.0000
A4 = 9.44678E-05
A6 = 5.47705E-07
A8 = 1.37698E-23
A10 = 0.00000 E + 00
A12 = 0.00000 E + 00

Plane 21 κ = -1.0412
A4 = 8.07840E-06
A6 = -1.60525E-07
A8 = -3.84486E-09
A10 = 0.00000 E + 00
A12 = 0.00000 E + 00

[Various data]
Magnification ratio 4.71
W M T
f 10.29845 32.00216 48.49978
FNO 3.60 5.06 5.79
ω 39.76047 13.63173 9.16599
Y 8.00 8.00 8.00
φ 7.80 8.30 8.30
TL 79.34243 95.80944 105.57918
BF 13.25602 13.25602 13.25602

[Variable interval data]
W M T
f 10.29845 32.00216 48.49978
D5 1.80000 16.93666 22.35926
D12 18.49692 5.54052 1.80069
D14 3.61695 3.90524 5.82908
D23 5.42688 19.42534 25.58847

[Focus group movement amount at focusing]
W M T
Object image distance 1.00m 1.00m 1.00m
Travel distance 0.2652 0.7481 1.2334

[Lens group data]
Group number Group initial surface Group focal length G1 1 57.25524
G2 6-11.09964
G3 13 49.98341
G4 15 28.96589
G5 24 65.16201

[Conditional expression corresponding value]
Conditional Expression (1) f3 / ft = 1.031
Conditional Expression (2) f4 / ft = 0.597
Conditional Expression (3) fR / fw = 6.326
Conditional Expression (4) (-f2) / fw = 1.078
Conditional Expression (5) (d3t−d3w) /fw=0.215

  It is understood from Table 1 that the variable magnification optical system ZL1 according to this example satisfies the conditional expressions (1) to (5).

FIG. 2 shows various aberrations (spherical aberration, astigmatism, distortion, coma and lateral chromatic aberration) of the zoom optical system ZL1 of the first embodiment at infinity focusing. (A) shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state. FIG. 3 shows various aberrations (spherical aberration diagram, astigmatism diagram, distortion aberration diagram, coma aberration) at the time of focusing on a short distance object (object distance 1.00 m) of the zoom optical system ZL1 according to the first example. (A) and (a) show a wide-angle end state, (b) an intermediate focal length state, and (c) a telephoto end state, respectively. FIG. 4 is a meridional lateral aberration diagram of the first exemplary zoom lens system ZL1 at the time of infinity focusing (the shift amount of the anti-vibration lens group = 0.1 mm) when the image blurring correction is performed at infinity. a) shows the wide-angle end state, b) shows the intermediate focal length state, and c) shows the telephoto end state. In this example, optical performance at the time of image stabilization is shown by meridional lateral aberration diagrams corresponding to the screen center and the image height of ± 5.6 mm, as shown in FIGS. 4 (a) to 4 (c).

  In each aberration diagram, FNO is the F number, NA is the numerical aperture of the light beam emitted from the lens closest to the image side, A is the light incident angle or half angle of view (unit: "°"), H0 is the object height (unit: " mm "), Y indicates the image height. d shows the aberration in d line, g shows the aberration in g line. Moreover, the thing without d and g shows the aberration in d line. In the spherical aberration diagram, the solid line indicates spherical aberration. In astigmatism diagrams, a solid line indicates a sagittal image plane, and a broken line indicates a meridional image plane. In coma aberration diagrams, a solid line indicates coma aberration in the meridional direction. The same reference numerals as in this example are used also in the aberration charts of the examples which will be described later.

  As is apparent from the respective aberration diagrams shown in FIGS. 2 to 4, the variable magnification optical system ZL1 according to the first example extends from the wide-angle end state to the telephoto end state and from the infinity in-focus condition to the short distance It can be seen that aberrations are well corrected over the in-focus condition and have high optical performance. In addition, it is understood that high image forming performance is provided at the time of image shake correction.

Second Embodiment
The second embodiment will be described with reference to FIGS. 5 to 8 and Table 2. As shown in FIG. 5, the variable magnification optical system ZL (ZL2) according to the second example has a first lens group G1 having a positive refractive power, which is arranged in order from the object side along the optical axis; From a second lens group G2 having a refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a positive refractive power Become. An aperture stop S is provided between the third lens group G3 and the fourth lens group G4, and the aperture stop S constitutes a fourth lens group G4. The fifth lens group G5 is a lens group closest to the image.

  The first lens group G1 has a convex surface facing 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, arranged in order from the object side along the optical axis And a positive meniscus lens L13.

  The second lens group G2 includes a negative meniscus lens L21 having a convex surface facing the object side, a negative meniscus lens L22 having a concave surface facing the object side, and a biconvex positive lens. It consists of the lens L23. The negative meniscus lens L21 is a composite aspherical lens of resin and glass in which the lens surface on the object side is aspherical.

  The third lens group G3 is composed of a positive meniscus lens L31 having a convex surface facing the object side. The positive meniscus lens L31 is a glass mold aspheric lens in which the lens surface on the object side is aspheric.

  The fourth lens group G4 includes a cemented lens of a negative meniscus lens L41 with a convex surface facing the object side and a biconvex positive lens L42 arranged in order from the object side along the optical axis. A cemented lens of a group G4A, a biconvex positive lens L43 and a negative meniscus lens L44 having a concave surface facing the object side, a negative meniscus lens L45 having a convex surface facing the object side and a positive meniscus having a convex surface facing the object side And a fourth sub lens group G4B configured of a cemented lens to the lens L46. The negative meniscus lens L44 is a glass mold aspheric lens in which the lens surface on the image side is aspheric.

  The fifth lens group G5 is composed of a positive meniscus lens L51 having a concave surface facing the object side.

In the variable magnification optical system ZL2 according to the present embodiment, the air gap between the first lens group G1 and the second lens group G2, the air gap between the second lens group G2 and the third lens group G3, and the third lens group are variable at the time of zooming. Lens group G3
The first lens group G1 to the fourth lens group G4 are arranged along the optical axis such that the air spacing between the second lens group G4 and the fourth lens group G4 and the air spacing between the fourth lens group G4 and the fifth lens group G5 change respectively. Moving. The fifth lens group G5 is fixed with respect to the image plane I.

Specifically, at the time of zooming from the wide-angle end state to the telephoto end state, the first lens group G1, the third lens group G3, and the fourth lens group G4 move to the object side. The second lens group G2 moves to the image side from the wide-angle end state to the intermediate focal length state, and moves to the object side from the intermediate focal length state to the telephoto end state. The aperture stop S moves integrally with the fourth lens group G4 to the object side.

  Thereby, at the time of zooming, the air gap between the first lens group G1 and the second lens group G2 increases, and the air gap between the second lens group G2 and the third lens group G3 decreases, and the third lens group G3 The air gap between the second lens group G4 and the fourth lens group G4 decreases from the wide-angle end state to the intermediate focal length state, and increases from the intermediate focal length state to the telephoto end state, and the air space between the fourth lens group G4 and the fifth lens group G5 Will increase. The air gap between the aperture stop S and the third lens group G3 decreases from the wide-angle end state to the intermediate focal length state, and increases from the intermediate focal length state to the telephoto end state.

  Focusing is performed by moving the third lens group G3 along the optical axis. In detail, at the time of focusing from an infinite distance object to a close distance object, the third lens unit G3 is moved to the image side along the optical axis.

  When an image blur occurs, image blur correction (vibration reduction) on the image plane I is performed by moving the fourth sub lens group G4A as a vibration reduction lens group so as to have a component in a direction perpendicular to the optical axis.

  Table 2 below shows values of respective items in the second embodiment. The surface numbers 1 to 26 in Table 2 correspond to the optical surfaces of m1 to m26 illustrated in FIG. 5.

(Table 2)
[Lens specification]
Face number R D nd d d
Object ∞
1 144.9435 1.6000 1.846660 23.80
2 57.9139 4.6578 1.696800 55.52
3-430. 8049 0.1000
4 49.1887 3.5211 1.696800 55.52
5 158.0589 D5 (variable)
* 6 504.4641 0.0800 1.560930 36.64
7 234.1101 1.0000 1.834810 42.73
8 9.4881 5.5305
9-17.0787 0.9276 1.741000 52.76
10-1027.3916 1.0145
11 34.5727 2.6835 1.808090 22.74
12-53.1261 D12 (variable)
* 13 24.3966 1.6530 1.588870 61.13
14 296.0192 D14 (variable)
15 ∞ 1.5000 (aperture)
16 17.3960 0.9000 1.883000 40.66
17 11.0000 2.8505 1.497820 82.57
18-48.0307 1. 5000
19 12.4669 2.8380 1.48790 70.32
20-14.1721 0.9000 1.851080 40.12
* 21-35.5823 0.1000
22 19.0885 0.9000 1.883000 40.66
23 7.1245 1.8774 1.620040 36.40
24 8.9496 D24 (variable)
25-30.0000 3.6500 1.696800 55.52
26-19.7882 BF
Image plane ∞

[Aspheric surface data]
Sixth face = = -1.9998
A4 = 2.80199 E-05
A6 = -2.77907E-07
A8 = 2.24720E-09
A10 = -8.56636E-12
A12 = 0.00000 E + 00

13th surface κ = 1.7623
A4 = -2.39838E-05
A6 = -7.89804E-08
A8 = 2.79454E-09
A10 = 0.00000 E + 00
A12 = 0.00000 E + 00

Plane 21 κ = -0.1893
A4 = -9.56775E-06
A6 = -6.24519E-07
A8 = 1.01416E-08
A10 = 0.00000 E + 00
A12 = 0.00000 E + 00

[Various data]
Magnification ratio 6.59
W M T
f 10.29976 39.99987 67.89953
FNO 3.64 5.06 5.81
ω 39.73502 10.92213 6.56887
Y 8.00 8.00 8.00
φ 8.60 9.90 9.90
TL 89.92002 109.96784 121.58326
BF 13.25085 13.25085 13.25085

[Variable interval data]
W M T
f 10.29976 39.99987 67.89953
D5 1.80000 24.18110 32.41506
D12 25.02141 7.23672 2.58 202
D14 4.80996 3.66893 5.14775
D24 25.2391 21.84636 28.40370

[Focus group movement amount at focusing]
W M T
Object image distance 1.00m 1.00m 1.00m
Travel distance 0.3072 0.9550 1.8445

[Lens group data]
Group number Group initial surface Group focal length G1 1 68.26199
G2 6-12.46728
G3 13 45.04911
G4 15 40.55521
G5 25 72.75019

[Conditional expression corresponding value]
Conditional Expression (1) f3 / ft = 0.663
Conditional Expression (2) f4 / ft = 0.597
Conditional Expression (3) fR / fw = 7.063
Conditional Expression (4) (−f2) /fw=1.210
Conditional Expression (5) (d3t-d3w) / fw = 0.033

  From Table 2, it can be seen that the variable magnification optical system ZL2 according to this example satisfies the conditional expressions (1) to (5).

FIG. 6 shows various aberrations (spherical aberration, astigmatism, distortion, coma and lateral chromatic aberration) of the zoom optical system ZL2 of the second example at infinity focusing. (A) shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state. FIG. 7 shows various aberrations (spherical aberration diagram, astigmatism diagram, distortion aberration diagram, coma aberration) at the time of focusing on a short distance object (object distance 1.00 m) of the zoom optical system ZL2 according to the second example. (A) and (a) show a wide-angle end state, (b) an intermediate focal length state, and (c) a telephoto end state, respectively. FIG. 8 is a meridional lateral aberration diagram when image shake correction is performed at infinity in focus of the variable magnification optical system ZL2 according to the second example (shift amount of anti-vibration lens group = 0.1 mm). a) shows the wide-angle end state, b) shows the intermediate focal length state, and c) shows the telephoto end state. In this example, optical performance at the time of image stabilization is shown by meridional lateral aberration diagrams corresponding to the screen center and the image height of ± 5.6 mm as shown in FIGS. 8 (a) to 8 (c).

  As is apparent from the respective aberration diagrams shown in FIGS. 6 to 8, the variable magnification optical system ZL2 according to the second example extends from the wide-angle end state to the telephoto end state and from the infinity in-focus condition to the close-in-focus condition. It can be seen that aberrations are well corrected over the in-focus condition and have high optical performance. In addition, it is understood that high image forming performance is provided at the time of image shake correction.

Third Embodiment
The third embodiment will be described with reference to FIGS. 9 to 12 and Table 3. The variable magnification optical system ZL (ZL3) according to the third example is, as shown in FIG. 9, a first lens group G1 having a positive refractive power and arranged in order from the object side along the optical axis; A second lens group G2 having a refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a negative refractive power; It consists of the 6th lens group G6 which has positive refractive power. An aperture stop S is provided between the third lens group G3 and the fourth lens group G4, and the aperture stop S constitutes a fourth lens group G4. The sixth lens group G6 is a lens group closest to the image.

  The first lens group G1 has a convex surface facing 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, arranged in order from the object side along the optical axis And a positive meniscus lens L13.

  The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens L21 with a convex surface facing the object side, a negative biconcave lens L22, and a positive meniscus with a convex surface facing the object side It consists of the lens L23. The negative lens L22 is a glass mold aspheric lens in which the lens surface on the object side is aspheric.

  The third lens group G3 is composed of a biconvex positive lens L31. The positive lens L31 is a glass mold aspheric lens in which the lens surface on the object side is aspheric.

  The fourth lens group G4 includes a cemented lens of a negative meniscus lens L41 with a convex surface facing the object side and a biconvex positive lens L42 arranged in order from the object side along the optical axis. The fourth sub lens group G4B is composed of a group G4A, and a cemented lens of a double convex positive lens L43 and a negative meniscus lens L44 having a concave surface facing the object side. The negative meniscus lens L44 is a glass mold aspheric lens in which the lens surface on the image side is aspheric.

  The fifth lens group G5 is composed of a negative meniscus lens L51 having a convex surface facing the object side.

  The sixth lens group G6 is composed of a positive meniscus lens L61 having a concave surface facing the object side.

  In the variable magnification optical system ZL3 according to the present embodiment, the air gap between the first lens group G1 and the second lens group G2, the air gap between the second lens group G2 and the third lens group G3, and the third lens group are variable at the time of zooming. The air spacing between the lens group G3 and the fourth lens group G4, the air spacing between the fourth lens group G4 and the fifth lens group G5, and the air spacing between the fifth lens group G5 and the sixth lens group G6 respectively change The first lens group G1 to the fifth lens group G5 move along the optical axis. The sixth lens group G6 is fixed to the image plane I.

  Specifically, at the time of zooming from the wide-angle end state to the telephoto end state, the first lens group G1, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 move to the object side. The second lens group G2 moves to the image side from the wide-angle end state to the intermediate focal length state, and moves to the object side from the intermediate focal length state to the telephoto end state. The aperture stop S moves integrally with the fourth lens group G4 to the object side.

  Thereby, at the time of zooming, the air gap between the first lens group G1 and the second lens group G2 increases, and the air gap between the second lens group G2 and the third lens group G3 decreases, and the third lens group G3 The air gap between the second lens group G4 and the fourth lens group G4 decreases from the wide-angle end state to the intermediate focal length state, and increases from the intermediate focal length state to the telephoto end state, and the air space between the fourth lens group G4 and the fifth lens group G5 The air gap between the fifth lens group G5 and the sixth lens group G6 increases. The air gap between the aperture stop S and the third lens group G3 decreases from the wide-angle end state to the intermediate focal length state, and increases from the intermediate focal length state to the telephoto end state.

  Focusing is performed by moving the third lens group G3 along the optical axis. In detail, at the time of focusing from an infinite distance object to a close distance object, the third lens unit G3 is moved to the image side along the optical axis.

When an image blur occurs, image blur correction (vibration reduction) on the image plane I is performed by moving the fourth sub lens group G4A as a vibration reduction lens group so as to have a component in a direction perpendicular to the optical axis.

  Table 3 below shows values of respective items in the third embodiment. The surface numbers 1 to 24 in Table 3 correspond to the optical surfaces m1 to m24 shown in FIG.

(Table 3)
[Lens specification]
Face number R D nd d d
Object ∞
1 270.7698 1.6000 1.84666 23.80
2 63.2289 4.7857 1.5891 13 61.22
3 -180.7756 0.1000
4 38.2772 3.872 1.69680 55.52
5 162.5542 D5 (variable)
6 222.4687 0.9000 1.72916 54.61
7 8.6817 5.3065
* 8 -19.5238 0.9000 1.69680 55.52
9 33.5766 0.1038
10 19.7682 2.5354 1.84666 23.80
11 434.3570 D11 (variable)
* 12 26.1871 1.7281 1.58887 61.13
13 -76.6701 D13 (variable)
14 ∞ 1.7051 (Aperture)
15 16.6.63 0.9002 1.83400 37.18
16 9.9827 2.6157 1.49782 82.57
17-36.7432 1.5000
18 16.2913 2.2592 1.51823 58.82
19-17.2434 0.9000 1.85108 40.12
* 20-31.3248 D20 (variable)
21 28.0868 0.9000 1.90265 35.72
22 9.2493 D22 (variable)
23-37.3758 2.2000 1.61772 49.81
24-18.1325 BF
Image plane ∞

[Aspheric surface data]
Eighth plane == 1.0000
A4 = 2.09316E-05
A6 = -8. 0797E-07
A8 = 2.75349E-08
A10 = -4.70299E-10
A12 = 2.62880E-12

12th surface == 1.0000
A4 = -4.37334E-05
A6 = 3.04727E-07
A8 = -6.38106E-09
A10 = 0.00000 E + 00
A12 = 0.00000 E + 00

Twentieth plane == 1.0000
A4 = 2.28740E-05
A6 = -3.19205E-07
A8 = -1.46715E-10
A10 = 0.00000 E + 00
A12 = 0.00000 E + 00

[Various data]
Magnification ratio 4.71
W M T
f 10.30000 32.00000 48.51858
FNO 3.53 5.00 5.72
ω 39.75617 13.57625 9.11928
Y 8.00 8.00 8.00
φ 8.20 8.80 8.80
TL 80.36557 92.30690 103.19342
BF 13.30097 13.30097 13.30097

[Variable interval data]
W M T
f 10.30000 32.00000 48.51858
D5 1.80638 15.63570 22.37678
D11 18.74841 4.51318 2.11693
D13 5.83635 4.73970 5.51292
D20 1.50000 3.72584 3.97118
D22 4.84649 16.06454 21.58766

[Focus group movement amount at focusing]
W M T
Object image distance 1.00m 1.00m 1.00m
Travel distance 0.1896 0.4064 0.6618

[Lens group data]
Group number Group initial surface Group focal length G1 1 60.91787
G2 6 -9.90833
G3 12 33. 35 587
G4 14 15.48045
G5 21-15.63253
G6 23 54.62879

[Conditional expression corresponding value]
Conditional Expression (1) f3 / ft = 0.687
Conditional Expression (3) fR / fw = 5.304
Conditional Expression (4) (-f2) / fw = 0.962
Conditional Expression (5) (d3t−d3w) /fw=−0.031

  From Table 3, it can be seen that the variable magnification optical system ZL3 according to this example satisfies the conditional expressions (1) and (3) to (5).

FIG. 10 shows various aberrations (spherical aberration, astigmatism, distortion, coma and lateral chromatic aberration) of the zoom optical system ZL3 of the third example at infinity focusing. (A) shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state. FIG. 11 shows various aberrations (spherical aberration diagram, astigmatism diagram, distortion aberration diagram, coma aberration) at the time of focusing on a short distance object (object distance 1.00 m) of the zoom optical system ZL3 according to the third example. (A) and (a) show a wide-angle end state, (b) an intermediate focal length state, and (c) a telephoto end state, respectively. FIG. 12 is a meridional lateral aberration diagram when performing image blur correction during infinity focusing of the variable magnification optical system ZL3 according to the third example (shift amount of the anti-vibration lens group = 0.1 mm), a) shows the wide-angle end state, b) shows the intermediate focal length state, and c) shows the telephoto end state. In this example, optical performance at the time of image stabilization is shown as a meridional lateral aberration diagram corresponding to the screen center and the image height of ± 5.6 mm, as shown in FIGS. 12 (a) to 12 (c).

  As is apparent from the respective aberration diagrams shown in FIGS. 10 to 12, the variable magnification optical system ZL3 according to the third example extends from the wide-angle end state to the telephoto end state and from the infinity in-focus condition to the close-in-focus condition. It can be seen that aberrations are well corrected over the in-focus condition and have high optical performance. In addition, it is understood that high image forming performance is provided at the time of image shake correction.

  According to each of the above embodiments, it is possible to realize a variable power optical system having high optical performance over the entire zoom range.

  In order to make the present invention easy to understand so far, the configuration requirements of the embodiment have been added and described, but it goes without saying that the present invention is not limited to this. The following contents can be suitably adopted within the range that does not impair the optical performance of the variable magnification optical system of the present application.

  The numerical examples of the variable magnification optical system ZL according to the present embodiment are shown as having five or six groups, but the present invention is not limited to this and can be applied to other group configurations (for example, seven groups etc.) It is. Specifically, the lens or lens group may be added to the most object side, or the lens or lens group may be added to the most image side. The lens group indicates a portion having at least one lens separated by an air gap that changes at the time of zooming.

  In the variable magnification optical system ZL according to the present embodiment, in order to focus from an infinite distance object to a close distance object, a part of the lens group, the entire one lens group, or a plurality of lens groups is a focusing lens group It may be configured to move in the optical axis direction. In the present embodiment, an example in which the third lens group G3 is a focusing lens group has been described. However, at least a part of the second lens group G2, at least a part of the third lens group G3, and the fourth lens group G4 At least one of them and at least one of the fifth lens group G5 may be used as a focusing lens group. Further, such a focusing lens group can also be applied to auto focusing, and is also suitable for driving by a motor for auto focusing (for example, an ultrasonic motor or the like).

  In the variable magnification optical system ZL according to the present embodiment, the entire lens unit or a partial lens unit is moved as a vibration reduction lens unit so as to have a component in a direction perpendicular to the optical axis or includes the optical axis Although the fourth sub lens group G4A has been described as an example of the configuration that corrects the image blur caused by camera shake or the like by rotationally moving (swinging) in the in-plane direction, the present invention is not limited thereto. For example, the third lens group At least a portion of G3, at least a portion of the fourth lens group G4, and at least a portion of the fifth lens group G5 may be used as a vibration reduction lens group.

In the variable magnification optical system ZL according to the present embodiment, the lens surface may be formed as a spherical surface, a flat surface, or an aspherical surface. When the lens surface is spherical or flat, it is preferable because lens processing and assembly adjustment are facilitated, and deterioration of optical performance due to processing and assembly adjustment errors can be prevented. In addition, even when the image plane shifts, it is preferable because there is little deterioration in the imaging performance. When the lens surface is aspheric, the aspheric surface is an aspheric surface formed by grinding, a glass mold aspheric surface formed of glass into an aspheric surface shape, or a composite aspheric surface formed of resin on the surface of glass with an aspheric surface shape. It may be any aspheric surface. The lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

  In the variable magnification optical system ZL according to this embodiment, the aperture stop S is preferably disposed in the fourth lens group G4 or in the vicinity thereof. The lens frame may substitute for the role without providing a member as the aperture stop.

  In the variable magnification optical system ZL according to this embodiment, each lens surface is provided with an anti-reflection film having high transmittance in a wide wavelength range in order to reduce flare and ghost and achieve high optical performance with high contrast. May be

ZL (ZL1 to ZL3) Variable magnification optical system G1 First lens group G2 Second lens group G3 Third lens group G4 Fourth lens group G4A fourth A sub lens group G4B fourth B sub lens group G5 fifth lens group G6 sixth Lens group S Aperture stop I Image plane 1 Camera (optical equipment)

Claims (15)

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 along the optical axis, and a positive lens And a fourth lens group having a refractive power and a fifth lens group having a negative refractive power,
During zooming, the distance between the first lens group and the second lens group, the distance between the second lens group and the third lens group, the distance between the third lens group and the fourth lens group, The distance between the fourth lens group and the fifth lens group changes,
A variable magnification optical system in which the lens unit closest to the image side is substantially fixed with respect to the image plane during zooming. 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 along the optical axis, and a positive lens A fourth lens group having a refractive power, a fifth lens group having a negative refractive power, and a sixth lens group,
During zooming, the distance between the first lens group and the second lens group, the distance between the second lens group and the third lens group, the distance between the third lens group and the fourth lens group, The distance between the fourth lens group and the fifth lens group, and the distance between the fifth lens group and the sixth lens group change,
A variable magnification optical system in which the lens unit closest to the image side is substantially fixed with respect to the image plane during zooming. The variable magnification optical system according to claim 1, wherein the following conditional expression is satisfied.
0.480 <f3 / ft <4.000
However,
ft: focal length of the variable magnification optical system in the telephoto end state,
f3: focal length of the third lens unit. The variable magnification optical system according to any one of claims 1 to 3, which satisfies the following conditional expression.
0.470 <f4 / ft <0.900
However,
ft: focal length of the variable magnification optical system in the telephoto end state,
f4: focal length of the fourth lens unit.   The variable magnification optical system according to any one of claims 1 to 4, wherein the lens group closest to the image has a positive refractive power. The variable magnification optical system according to any one of claims 1 to 5, which satisfies the following conditional expression.
3.000 <fR / fw <9.500
However,
fw: focal length of the variable magnification optical system in the wide-angle end state,
fR: focal length of the lens unit closest to the image side. The variable magnification optical system according to any one of claims 1 to 6, which satisfies the following conditional expression.
0.730 <(− f2) / fw <1.800
However,
fw: focal length of the variable magnification optical system in the wide-angle end state,
f2: focal length of the second lens group. The variable magnification optical system according to any one of claims 1 to 7, which satisfies the following conditional expression.
−0.100 <(d3t−d3w) / fw <0.330
However,
fw: focal length of the variable magnification optical system in the wide-angle end state,
d3w: distance on the optical axis from the lens surface closest to the image side of the third lens unit to the lens surface closest to the object side of the fourth lens unit in the wide-angle end state;
d3t: distance on the optical axis from the lens surface closest to the image in the third lens group to the lens surface closest to the object in the fourth lens group in the telephoto end state;   The variable magnification optical system according to any one of claims 1 to 8, wherein the first lens group moves toward the object side at the time of zooming from the wide angle end state to the telephoto end state.   The variable magnification optical system according to any one of claims 1 to 9, wherein an interval between the first lens group and the second lens group is increased at the time of zooming from the wide-angle end state to the telephoto end state.   The variable magnification optical system according to any one of claims 1 to 10, wherein an interval between the second lens group and the third lens group is decreased at the time of zooming from the wide angle end state to the telephoto end state.   The variable magnification optical system according to any one of claims 1 to 11, wherein the aperture stop is disposed between the third lens group and the fourth lens group.   The variable magnification optical system according to any one of claims 1 to 12, wherein the third lens unit moves along an optical axis at the time of focusing.   The variable magnification optical system according to any one of claims 1 to 13, wherein the third lens unit is moved to the image side at the time of focusing from an infinite distance object to a close distance object.   An optical apparatus on which the variable magnification optical system according to any one of claims 1 to 14 is mounted.

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