JP6539967B2 - Zoom lens, optical device, and method of manufacturing zoom lens - Google Patents

Description

  The present invention relates to a zoom lens, an optical device, and a method of manufacturing the zoom lens.

  Conventionally, along the optical axis, from the object side, the first lens group of positive refractive power, the second lens group of negative refractive power, the third lens group of positive refractive power, and negative refractive power A zoom lens has been proposed which comprises a fourth lens group D5 and a fifth lens group D4 having a positive refractive power, and performing zooming by moving each lens group (see, for example, Patent Document 1).

JP, 2013-164455, A

  However, in the conventional zoom lens, the zoom ratio of about 50 is a limit, and it is difficult to maintain good performance at higher zoom ratios.

  The present invention has been made in view of such problems, and it is an object of the present invention to provide a zoom lens, an optical device, and a method of manufacturing the zoom lens having good optical performance while having high magnification.

In order to achieve such an object, in the zoom lens according to the first aspect of the present invention, a first lens group having a positive refractive power and a first lens group having a negative refractive power are arranged in order from the object side along the optical axis. A lens group having two lens groups, a third lens group having a positive refractive power, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power; The first lens group is composed of three or more lenses, and the fifth lens group moves toward the image plane side during zooming from the wide-angle end state to the telephoto end state. The following conditional expressions are satisfied.

0.020 <(-f2) / ft <0.031
74.00 <AVE1Grpvd <80.00
36.00 <G1 vd <48.00
108.00 ≦ D12t / D12w <140.00
However,
f2: focal length of the second lens group in the telephoto end state,
ft: focal length of the entire system at the telephoto end state,
AVE1Grpvd: average of Abbe number based on the d-line of the lens in the first lens group,
G1vd: Abbe number based on the d-line of the lens disposed closest to the object in the first lens group
D12t: air gap between the first lens group and the second lens group in the telephoto end state,
D12w: Air space between the first lens group and the second lens group in the wide-angle end state.

A zoom lens according to a second aspect 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 refractive power, which are arranged in order from the object side along the optical axis. And the fourth lens group having a negative refractive power, and the fifth lens group having a positive refractive power, wherein the distance between the lens groups is changed to perform zooming. The first lens group includes three or more lenses, and the fifth lens group moves toward the image plane side during zooming from the wide-angle end state to the telephoto end state, and the following conditional expression is satisfied .

0.020 <(-f2) / ft <0.031
74.00 <AVE1Grpvd <80.00
36.00 <G1 vd <48.00
12.34 <β2t / β2w <14.40
However,
f2: focal length of the second lens group in the telephoto end state,
ft: focal length of the entire system in the telephoto end state,
AVE1Grpvd: average of Abbe number based on the d-line of the lens in the first lens group,
G1vd: Abbe number based on the d-line of the lens disposed closest to the object in the first lens group
β2t: Magnification of the second lens unit in the telephoto end state
β2 w: Magnification of the second lens group in the wide-angle end state.

A zoom lens according to a third aspect of the present invention includes a first lens group having positive refractive power, a second lens group having negative refractive power, and a positive refractive power, which are arranged in order from the object side along the optical axis. And the fourth lens group having a negative refractive power, and the fifth lens group having a positive refractive power, wherein the distance between the lens groups is changed to perform zooming. The first lens group includes three or more lenses, and the fifth lens group moves toward the image plane side during zooming from the wide-angle end state to the telephoto end state, and the following conditional expression is satisfied .

0.020 <(-f2) / ft <0.031
108.00 ≦ D12t / D12w ≦ 137.01
However,
f2: focal length of the second lens group in the telephoto end state,
ft: focal length of the entire system in the telephoto end state,
D12t: air gap between the first lens group and the second lens group in the telephoto end state,
D12w: Air space between the first lens group and the second lens group in the wide-angle end state.

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

  In the zoom lens manufacturing method according to the present invention, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a positive refractive index are arranged in order from the object side along the optical axis. Zoom that zooms by changing the distance between each lens group and having a third lens group with a power, a fourth lens group with a negative refractive power, and a fifth lens group with a positive refractive power In the lens manufacturing method, the first lens group is composed of three or more lenses, and the fifth lens group moves toward the image plane side during zooming from the wide-angle end state to the telephoto end state. Each lens is disposed in the lens barrel so as to satisfy the following conditional expression.

0.020 <(-f2) / ft <0.031
74.00 <AVE1Grpvd <80.00
36.00 <G1 vd <48.00
108.00 ≦ D12t / D12w <140.00
However,
f2: focal length of the second lens group in the telephoto end state,
ft: focal length of the entire system at the telephoto end state,
AVE1Grpvd: average of Abbe number based on the d-line of the lens in the first lens group,
G1vd: Abbe number based on the d-line of the lens disposed closest to the object in the first lens group
D12t: air gap between the first lens group and the second lens group in the telephoto end state,
D12w: Air space between the first lens group and the second lens group in the wide-angle end state.

  According to the present invention, it is possible to provide a zoom lens, an optical device, and a method of manufacturing the zoom lens having high optical power while having high magnification.

FIG. 1 is a cross-sectional view showing a configuration of a zoom lens according to Example 1. (W) shows the position of each lens group in the wide-angle end state, (M) in the intermediate focal length state, and (T) in the telephoto end state. FIG. 7 shows various aberrations that occurred at the shooting distance at infinity of the zoom lens according to the first example, (a) at the wide-angle end, (b) at the intermediate focal length, and (c) at the telephoto end. FIG. 7 is a cross-sectional view showing the configuration of a zoom lens according to Example 2. (W) shows the position of each lens group in the wide-angle end state, (M) in the intermediate focal length state, and (T) in the telephoto end state. FIG. 7 shows various aberrations that the zoom lens according to the second example at a shooting distance of infinity, in which (a) shows the wide-angle end, (b) shows the intermediate focal length, and (c) shows the telephoto end. FIG. 8 is a cross-sectional view showing the configuration of a zoom lens according to Example 3, (W) showing the wide-angle end state, (M) showing the intermediate focal length state, and (T) showing the position of each lens group in the telephoto end state. FIG. 7 shows various aberrations that the zoom lens according to Example 3 at a shooting distance of infinity, in which (a) shows the wide-angle end, (b) shows the intermediate focal length, and (c) shows the telephoto end. FIG. 13 is a cross-sectional view showing the configuration of a zoom lens according to Example 4. (W) shows the position of each lens group in the wide-angle end state, (M) in the intermediate focal length state, and (T) in the telephoto end state. FIG. 7 shows various aberrations that the zoom lens according to the fourth example at a shooting distance of infinity, in which (a) shows the wide-angle end, (b) shows the intermediate focal length, and (c) shows the telephoto end. FIG. 13 is a cross-sectional view showing the configuration of a zoom lens according to Example 5. (W) shows the position of each lens group in the wide-angle end state, (M) in the intermediate focal length state, and (T) in the telephoto end state. FIG. 16 shows various aberrations that occurred at the shooting distance at infinity of the zoom lens according to the fifth example, (a) at the wide-angle end, (b) at the intermediate focal length, and (c) at the telephoto end. FIG. 16 is a cross-sectional view showing a configuration of a zoom lens according to Example 6. (W) shows the position of each lens group in the wide-angle end state, (M) in the intermediate focal length state, and (T) in the telephoto end state. FIG. 13 shows various aberrations that occurred at the shooting distance at infinity of the zoom lens according to the sixth example, (a) at the wide-angle end, (b) at the intermediate focal length, and (c) at the telephoto end. (A) is a front view of a digital still camera, (b) is a rear view of the digital still camera. It is sectional drawing along arrow AA 'in Fig.13 (a). It is a flowchart which shows the manufacturing method of the zoom lens which concerns on this embodiment.

  Hereinafter, embodiments will be described with reference to the drawings. As shown in FIG. 1, the zoom lens ZL according to the present embodiment includes, in order from the object side along the optical axis, a first lens group G1 having a positive refractive power, and a second lens group having a negative refractive power. Each lens group includes 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 The first lens group G1 is composed of three or more lenses, and the fifth lens group G5 is moved toward the image plane side during zooming from the wide-angle end state to the telephoto end state. It moves and the following conditional expression (1) is satisfied.

0.020 <(− f2) / ft <0.031 (1)
However,
f2: focal length of the second lens group G2 in the telephoto end state,
ft: focal length of the entire system in the telephoto end state.

  Conditional expression (1) is a conditional expression for reducing spherical aberration and coma by zooming.

  If the lower limit value of the conditional expression (1) is exceeded, the refractive power of the second lens group G2 in the telephoto end state becomes too strong. For this reason, it is necessary to make the refracting power of other lens groups stronger as well. If the refractive power of the first lens group G1 is increased, it becomes difficult to correct spherical aberration and coma in the telephoto end state. When the refractive power of the third lens group G3 is increased, the spherical aberration in the third lens group G3 is increased, and the spherical aberration and the coma aberration are deteriorated in the entire variable power region.

  If the upper limit value of the conditional expression (1) is exceeded, the refractive power of the second lens group G2 in the telephoto end state becomes too weak. For this reason, it is necessary to weaken the refractive power of the other lens groups as well. If the refractive power of the first lens group G1 is weakened, the total length of the lens barrel is increased, and if it is intended to maintain the lens barrel size, it is necessary to strengthen the refractive power of the third lens group G3. The spherical aberration becomes large, and the spherical aberration and the coma aberration deteriorate in the entire variable power region. In addition, if the refractive power of the third lens group G3 is weakened, the total length of the lens barrel is increased, and if it is intended to maintain the lens barrel size, it is necessary to strengthen the refractive power of the first lens group G1. The spherical aberration at the end of the lens increases and the spherical aberration and coma at the telephoto end state deteriorate.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit value of the conditional expression (1) to 0.024.

  The zoom lens ZL according to the present embodiment preferably satisfies the following conditional expressions (2) and (3).

74.00 <AVE1 Grpvd <80.00 (2)
36.00 <G1 vd <48.00 ... (3)
However,
AVE1Grpvd: average of Abbe number based on the d-line of the lens in the first lens group G1,
G1 vd: Abbe's number based on the d-line of the lens L11 disposed closest to the object side in the first lens group G1.

  Conditional expression (2) is a conditional expression for reducing the occurrence of axial chromatic aberration and lateral chromatic aberration. If the lower limit value of conditional expression (2) is exceeded, the average value of the Abbe numbers of the lenses constituting the first lens group G1 becomes smaller than the focal length of the entire system in the telephoto end state. It becomes difficult to control. If the upper limit value of the conditional expression (2) is exceeded, the average value of the Abbe numbers of the lenses constituting the first lens group G1 becomes larger than the focal length of the entire system in the telephoto end state. This means that the lenses constituting the first lens group G1 generally have weak refractive power. If the refractive power of the first lens group G1 is weakened, the lens barrel size is increased, and if the refractive power of the third lens group G3 is increased to maintain the lens barrel size, it is difficult to suppress spherical aberration and coma. .

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit value of the conditional expression (2) to 74.50.

  Conditional expression (3) is a conditional expression for reducing the occurrence of axial chromatic aberration and lateral chromatic aberration. Below the lower limit value of the conditional expression (3), the Abbe number of the lens L11 disposed closest to the object in the first lens group G1 becomes smaller than the focal length of the entire system in the telephoto end state. It becomes difficult to suppress lateral chromatic aberration. If the upper limit value of the conditional expression (3) is exceeded, the Abbe number of the lens L11 in the first lens group G1 becomes larger than the focal length of the entire system in the telephoto end state, and the lens generally weakens in refractive power. As described above, when the refractive power of the lens L11 disposed closest to the object side becomes weak, it is difficult to suppress the chromatic aberration, and to suppress the chromatic aberration, it is necessary to weaken the refractive power of the lens L12. The refractive power at G1 becomes weak, and the lens barrel size becomes long. If the refractive power of the third lens group G3 is increased to maintain the lens barrel size, it becomes difficult to suppress spherical aberration and coma.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit value of the conditional expression (3) to 37.00.

  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 47.50.

  The zoom lens ZL according to the present embodiment preferably satisfies the following conditional expression (4).

100.00 <D12t / D12w <140.00 (4)
However,
D12t: air gap between the first lens group G1 and the second lens group G2 in the telephoto end state,
D12w: Air gap between the first lens group G1 and the second lens group G2 in the wide-angle end state.

  Conditional expression (4) is a conditional expression for reducing fluctuations of spherical aberration, coma aberration, and magnification chromatic aberration due to zooming. If the lower limit value of the conditional expression (4) is exceeded, the distance between the first lens group G1 and the second lens group G2 in the telephoto end state becomes too narrow, so it is necessary to strengthen the refractive power of the first lens group G1. . Therefore, if the refractive index of the positive lens in the first lens group G1 is increased, it becomes difficult to correct spherical aberration, coma aberration, and lateral chromatic aberration in the telephoto end state. If the upper limit value of the conditional expression (4) is exceeded, the distance between the first lens group G1 and the second lens group G2 in the telephoto end state becomes too wide, so the total length of the lens barrel becomes long. In addition, it is necessary to weaken the refractive power of the first lens group G1, but it is possible to cope with the extent to which the refractive power of the second lens group G2 is increased, but suppressing the fluctuation of the chromatic aberration due to the magnification change. It becomes difficult.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit value of the conditional expression (4) to 105.00.

  In order to secure the effect of the present embodiment, it is preferable to set the upper limit value of the conditional expression (4) to 138.00.

  The zoom lens ZL according to the present embodiment preferably satisfies the following conditional expression (5).

12.34 <β2t / β2w <14.40 (5)
However,
β2t: Magnification of the second lens group G2 in the telephoto end state
β2 w: Magnification of the second lens group G2 in the wide-angle end state.

  Conditional expression (5) is a conditional expression for reducing fluctuations of spherical aberration and coma due to zooming. Below the lower limit value of the conditional expression (5), the contribution of the second lens group G2 at the time of zooming becomes too small. That is, the third lens group G3 needs to be responsible for more magnification change. If the refractive power of the third lens group G3 is increased in order to maintain the lens barrel size, it becomes difficult to correct spherical aberration in the telephoto end state or correct spherical aberration and coma in the entire variable power region. If the upper limit value of the conditional expression (5) is exceeded, the contribution of the second lens group G2 at the time of zooming becomes too large. When the moving amount of the second lens group G2 is large, it becomes difficult to maintain the lens barrel size. In addition, when the refractive power of the second lens group G2 is strong, it becomes difficult to correct spherical aberration and coma in the entire variable power region.

  In order to secure the effect of the present embodiment, it is preferable to set the upper limit value of the conditional expression (5) to 14.35.

  The zoom lens ZL according to the present embodiment preferably satisfies the following conditional expression (6).

0.04 <f3 / ft <0.06 (6)
However,
f3: The focal length of the third lens group G3 in the telephoto end state.

  Conditional expression (6) is a conditional expression for reducing the fluctuation of the spherical aberration due to the magnification change. If the lower limit value of the conditional expression (6) is exceeded, the refractive power of the third lens group G3 in the telephoto end state becomes too strong. Then, the spherical aberration in the third lens group G3 becomes large. It becomes difficult to correct spherical aberration and coma in the entire variable power region. If the upper limit value of the conditional expression (6) is exceeded, the refractive power of the third lens group G3 in the telephoto end state becomes too weak. As a result, the amount of movement of the third lens group G3 becomes large, which makes it difficult to maintain the lens barrel size. If the refractive power of the first lens group G1 is increased in order to maintain the lens barrel size, correction of spherical aberration and coma aberration in the entire variable power region becomes difficult.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit value of the conditional expression (6) to 0.045.

  In the zoom lens ZL according to the present embodiment, the third lens group G3 is configured of a positive lens, a negative lens, a negative lens, and a positive lens, arranged in order from the object side along the optical axis. preferable.

  With this configuration, it is possible to correct spherical aberration and coma aberration for each wavelength in the telephoto end state with a good balance.

  In the zoom lens ZL according to the present embodiment, it is preferable that the third lens group G3 have at least one aspheric lens.

  With this configuration, spherical aberration and coma can be corrected well.

  According to the zoom lens ZL according to the present embodiment having the configuration as described above, it is possible to realize a zoom lens having good optical performance while having high magnification.

  FIGS. 13 and 14 show the configuration of a digital still camera CAM (optical apparatus) as an optical apparatus provided with the zoom lens ZL described above. In this digital still camera CAM, when the power button (not shown) is pressed, the shutter (not shown) of the photographing lens (zoom lens ZL) is opened, and light from an object (object) is collected by the zoom lens ZL. An image is formed on an imaging device C (for example, a CCD, a CMOS, etc.) disposed on the plane I (see FIG. 1). The subject image formed on the imaging device C is displayed on the liquid crystal monitor M disposed behind the digital still camera CAM. After the photographer decides the composition of the subject image while looking at the liquid crystal monitor M, the photographer depresses the release button B1 to shoot the subject image with the imaging device C, and stores and saves the image in a memory (not shown).

  The camera CAM is provided with an auxiliary light emitting unit EF that emits auxiliary light when the subject is dark, a function button B2 used for setting various conditions of the digital still camera CAM, and the like. Here, a compact type camera in which the camera CAM and the zoom lens ZL are integrally formed is exemplified, but as an optical device, even a single-lens reflex camera in which a lens barrel having the zoom lens ZL and a camera body main body can be detachable good.

  According to the camera CAM according to the present embodiment having the above configuration, by mounting the above-described zoom lens ZL as a shooting lens, a camera having good optical performance can be realized while having high magnification. Can.

  Subsequently, a method of manufacturing the above-described zoom lens ZL will be described with reference to FIG. First, in the lens barrel, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a positive refractive power, which are arranged in order from the object side along the optical axis Has a third lens group G3 having a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. Thus, each lens is arranged (step ST10). At this time, each lens is arranged so that the first lens group G1 is configured of three or more lenses (step ST20). The fifth lens group G5 arranges each lens so as to move to the image plane side at the time of zooming from the wide-angle end state to the telephoto end state (step ST30). Further, each lens is arranged so as to satisfy the following conditional expression (1) (step ST40).

0.020 <(− f2) / ft <0.031 (1)
However,
f2: focal length of the second lens group G2 in the telephoto end state,
ft: focal length of the entire system in the telephoto end state.

  As an example of the lens arrangement according to the present embodiment, as shown in FIG. 1, a cemented lens including, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12; A positive meniscus lens L13 having a convex surface facing the object side and a positive meniscus lens L14 having a convex surface facing the object side are arranged to form a first lens group G1, and a negative meniscus lens L21 having a concave surface facing the image side A negative meniscus lens L22 with a concave surface facing the side, a biconvex positive lens L23, and a biconcave negative lens L24 are arranged to form a second lens group G2, a biconvex positive lens L31, and an image The third lens unit includes a negative meniscus lens L32 having a concave surface facing the side, and a cemented lens including a negative meniscus lens L33 having a concave surface facing the image side and a positive lens L34 having a biconvex shape. The fourth lens group G4 includes a cemented lens including a biconvex positive lens L41 and a biconcave negative lens L42, and a concave surface facing the biconvex positive lens L51 and the object side. A cemented lens composed of a negative meniscus lens L52 is disposed to form a fifth lens group G5. The zoom lens ZL is manufactured by arranging each lens group prepared in this manner in the above-described procedure.

  According to the above manufacturing method of the zoom lens ZL, it is possible to manufacture a zoom lens having good optical performance while having high magnification.

  Each example according to the present embodiment will be described based on the drawings. Tables 1 to 6 are shown below, and these are tables of each item in the first to sixth 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, C-line (wavelength 656.3 nm), d-line (wavelength 587.6 nm), F-line (wavelength 486.1 nm), and g-line (wavelength 435.8 nm) are selected as calculation targets of aberration characteristics.

  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 "1.0000" 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)

  In [All specifications] in the table, f is the focal length of the whole lens system, Fno is the F number, ω is the half angle of view (maximum incident angle, unit: °), Y is the image height, and Bf is on the optical axis The distance from the lens last surface to the paraxial image plane, TL represents the total lens length (the distance from the lens front surface to the lens last surface on the optical axis plus Bf). However, Bf (air) and TL (air) are values obtained by converting the filter FL into air.

  In [Variable distance data] in the table, values of variable distances Di in respective states of the wide angle end, the intermediate focal length, and the telephoto end are shown. Di represents a variable interval between the i-th surface and the (i + 1) -th surface.

  In [lens group data] in the table, G indicates the group number, the first surface of the group indicates the surface number on the most object side of each group, and the group focal length indicates the focal length of each group.

  In [Conditional Expression] in the table, values corresponding to the above-mentioned conditional expressions (1) to (6) are shown.

  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 zoom lens has a proportional magnification 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)
The first embodiment will be described with reference to FIG. 1, FIG. 2 and Table 1. As shown in FIG. 1, the zoom lens ZL (ZL1) according to the first example 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. And a fourth lens group G4 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. Ru.

  The first lens group G1 is a cemented lens consisting of a negative meniscus lens L11 having a concave surface facing the image side and a biconvex positive lens L12 arranged in order from the object side along the optical axis, and a convex surface on the object side It consists of a positive meniscus lens L13 directed and a positive meniscus lens L14 convex on the object side.

  The second lens group G2 includes a negative meniscus lens L21 having a concave surface facing the image side, a negative meniscus lens L22 having a concave surface facing the object side, and a biconvex positive lens. It comprises a lens L23 and a biconcave negative lens L24.

  The third lens group G3 has a biconvex positive lens L31, a negative meniscus lens L32 with a concave surface facing the image side, and a negative meniscus with a concave surface facing the image side, which are arranged in order from the object side along the optical axis It comprises a cemented lens consisting of a lens L33 and a biconvex positive lens L34. Both surfaces of the biconvex positive lens L31 are aspheric.

  The fourth lens group G4 is composed of a cemented lens composed of a biconvex positive lens L41 and a biconcave negative lens L42 arranged in order from the object side along the optical axis.

  The fifth lens group G5 is composed of a cemented lens including a biconvex positive lens L51 and a negative meniscus lens L52 having a concave surface facing the object side, which are arranged in order from the object side along the optical axis. The object side surface of the biconvex positive lens L51 is an aspheric surface.

  An aperture stop S is provided on the object side of the third lens group G3 for the purpose of adjusting the amount of light.

  A filter FL is provided on the image side of the fifth lens group G5. The filter FL is configured of a low pass filter, an infrared cut filter, or the like for cutting a spatial frequency higher than the limit resolution of the solid-state imaging device, such as a CCD disposed on the image plane I.

  The zoom lens ZL1 according to the present embodiment includes all lenses from the first lens group G1 to the fifth lens group G5 so that the distance between the lens groups changes upon zooming from the wide-angle end state to the telephoto end state. Move the group. Specifically, the first lens group G1 is moved to the object side. The second lens group G2 is once moved to the image plane side, and then moved to the object side. The third lens group G3 is moved to the object side. The fourth lens group G4 is once moved to the image plane side, and then moved to the object side. The fifth lens group G5 is moved to the image plane side. The aperture stop S is moved to the object side integrally with the third lens group G3.

  Table 1 below shows values of respective items in the first embodiment. The surface numbers 1 to 33 in Table 1 correspond to the optical surfaces m1 to m33 shown in FIG.

(Table 1)
[Lens specification]
Face number R D nd d d
Object ∞
1 334.8603 2.3000 1.7859 44.17
2 83.1077 7.0000 1.4370 95.10
3-772.5727 0.1000
4 87.2537 5.8122 1.4978 82.57
5 1342.415 0.1000
6 98.7260 4.5143 1.4978 82.57
7 342.9176 D7 (variable)
8 41.9147 1.0000 1.8830 40.66
9 11.9219 6.5000
10-20.7730 0.8000 1.8348 42.73
11-344.1828 0.1000
12 30.5819 2.6713 1.9459 17.98
13 -83.2782 1.5000
14-19.1496 0.7000 1.6700 57.35
15 4309.2857 D15 (variable)
16 0.1 0.1000 (aperture S)
* 17 11.4711 2.7045 1.5533 71.68
* 18-91.6831 2.9489
19 25.5216 1.0000 1.9031 31.31
20 10.5793 1.8797
21 16.4639 0.5000 1.7859 44.17
22 15.0193 3.0297 1.4978 82.57
23-25.7395 D23 (variable)
24 115.7933 2.6797 1.5317 48.78
25-25.8235 0.5000 1.4978 82.57
26 15.9526 D26 (variable)
* 27 19.2159 2.2519 1.5891 61.15
28 -20.0000 0.5000 1.7174 29.57
29 -101.2812 D29 (variable)
30 0.2 0.2100 1.5168 63.88
31 0.8 0.8500
32 0.5 0.5000 1.5168 63.88
33 B Bf
Image plane ∞

[Aspheric surface data]
Face number κ A4 A6 A8 A10
17 0.7787 -4.4127E-05 2.5417E-07 6.1315E-09 0.0000E + 00
18 1.0000 1.2195E-04 -4.0857E-08 7.2014E-09 -6.1745E-11
27 -34.1326 1.0673E-04 -3.2846E-06 5.1727E-08 0.0000E + 00

[Overall specifications]
Zoom ratio 87.00
Wide-angle end Mid-focus Telephoto end f 4.430 41.320 385.415
Fno 2.69789 4.62051 7.46514
ω 43.38857 5.48852 0.59127
Bf 0.400 0.400 0.400
Bf (Air) 6.253 1.750 0.942
TL 126.5640 167.9134 209.7638
TL (air) 126. 8060 168.1554 210. 0058

[Variable interval data]
Variable interval Wide-angle end Mid-focus Telephoto end
D7 0.75072 67.39058 102.85326
D15 57.5468 15.77846 2.48969
D23 3.10183 20.52426 15.49812
D26 6.64433 10.19066 35.70666
D29 5.61149 1.10796 0.30000

[Lens group data]
Group number Group initial surface Group focal length G1 1 129.99999
G2 8-10.36057
G3 17 19.81736
G4 24 -40.00000
G5 27 31.99999

[Conditional expression]
Conditional Expression (1) (-f2) / ft = 0.027
Conditional Expression (2) AVE1Grpvd = 76.10
Conditional Expression (3) G1vd = 44.17
Conditional Expression (4) D12t / D12w = 137.01
Conditional Expression (5) β2t / β2w = 13.50
Conditional Expression (6) f3 / ft = 0.051

  It is understood from Table 1 that the zoom lens ZL1 according to the present example satisfies the conditional expressions (1) to (6).

  FIG. 2 shows various aberrations (spherical aberration, astigmatism, distortion, coma and chromatic aberration of magnification) of the zoom lens ZL1 according to Example 1 at infinity. Shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state.

  In each aberration diagram, FNO denotes an F number, and A denotes a half angle of view (unit: °) with respect to each image height. d shows the aberration in d line, g shows g line, C shows C line, and F shows F line. Also, those not described indicate aberrations at the d-line. In astigmatism diagrams, a solid line indicates a sagittal image plane, and a broken line indicates a meridional image plane. The same reference numerals as in this example are used also in the aberration charts of the examples which will be described later.

  As apparent from the respective aberration diagrams shown in FIG. 2, it is understood that the zoom lens ZL1 according to the first example has various aberrations well corrected and has excellent imaging performance.

Second Embodiment
The second embodiment will be described with reference to FIG. 3, FIG. 4 and Table 2. As shown in FIG. 3, the zoom lens ZL (ZL2) according to the second 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. And a fourth lens group G4 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. Ru.

  The first lens group G1 is a cemented lens consisting of a negative meniscus lens L11 having a concave surface facing the image side and a biconvex positive lens L12 arranged in order from the object side along the optical axis, and a convex surface on the object side It consists of a positive meniscus lens L13 directed and a positive meniscus lens L14 convex on the object side.

  The second lens group G2 includes a negative meniscus lens L21 having a concave surface facing the image side, a negative meniscus lens L22 having a concave surface facing the object side, and a biconvex positive lens. It comprises a lens L23 and a biconcave negative lens L24.

  The third lens group G3 has a biconvex positive lens L31, a negative meniscus lens L32 with a concave surface facing the image side, and a negative meniscus with a concave surface facing the image side, which are arranged in order from the object side along the optical axis It comprises a cemented lens consisting of a lens L33 and a biconvex positive lens L34. Both surfaces of the biconvex positive lens L31 are aspheric.

  The fourth lens group G4 is composed of a cemented lens composed of a biconvex positive lens L41 and a biconcave negative lens L42 arranged in order from the object side along the optical axis.

  The fifth lens group G5 is composed of a cemented lens including a biconvex positive lens L51 and a negative meniscus lens L52 having a concave surface facing the object side, which are arranged in order from the object side along the optical axis. The object side surface of the biconvex positive lens L51 is an aspheric surface.

  An aperture stop S is provided on the object side of the third lens group G3 for the purpose of adjusting the amount of light.

  A filter FL is provided on the image side of the fifth lens group G5. The filter FL is configured of a low pass filter, an infrared cut filter, or the like for cutting a spatial frequency higher than the limit resolution of the solid-state imaging device, such as a CCD disposed on the image plane I.

  The zoom lens ZL2 according to the present embodiment includes all lenses from the first lens group G1 to the fifth lens group G5 so that the distance between the lens groups changes upon zooming from the wide-angle end state to the telephoto end state. Move the group. Specifically, the first lens group G1 is moved to the object side. The second lens group G2 is moved to the image plane side. The third lens group G3 is once moved to the object side, and then moved to the image plane side. The fourth lens group G4 is once moved to the image plane side, and then moved to the object side. The fifth lens group G5 is moved to the image plane side. The aperture stop S is moved to the object side integrally with the third lens group G3.

  Table 2 below shows values of respective items in the second embodiment. The surface numbers 1 to 33 in Table 2 correspond to the optical surfaces m1 to m33 shown in FIG. 3.

(Table 2)
[Lens specification]
Face number R D nd d d
Object ∞
1 332.6865 2.3000 1.7880 47.35
2 68.7077 7.9529 1.4370 95.10
3-792.4624 0.1000
4 75.9597 6.6000 1.4978 82.57
5 1080.6696 0.1000
6 95.1129 5.2000 1.4978 82.57
7 572.0061 D7 (variable)
8 52.5449 1.0000 1.8348 42.73
9 11.4702 5.7000
10 -19.4639 0.8000 1.8160 46.59
11-138.4066 0.1000
12 25.9493 2.6314 1.9459 17.98
13-143.3398 1.5000
14-21.1331 0.7000 1.7130 53.94
15 85.8491 D15 (variable)
16 0.1 0.1000 (aperture S)
* 17 9.3923 3.0788 1.5533 71.68
* 18-154.0447 2.1252
19 20.7239 1.0000 1.9108 35.25
20 8.2675 2.0000
21 10.2754 0.5000 1.7859 44.17
22 7.9325 4.0000 1.4875 70.32
23-26.6811 D23 (variable)
24 44.3901 2.2259 1.5317 48.78
25 -233.6852 0.5000 1.4978 82.57
26 12.9802 D26 (variable)
* 27 17. 9809 2.2407 1.5891 61. 15
28 -20.0000 0.5000 1.7174 29.57
29 -147.4991 D29 (variable)
30 0.2 0.2100 1.5168 63.88
31 0.8 0.8500
32 0.5 0.5000 1.5168 63.88
33 B Bf
Image plane ∞

[Aspheric surface data]
Face number κ A4 A6 A8 A10
17 0.8353 -4.6313E-05 -3.6242E-07 2.9634E-09 0.0000E + 00
18 1.0000 6.7198E-05 -4.0471E-07 1.0833E-08 -6.1745E-11
27 -0.5478 2.2570E-05 -1.3489E-06 4.5185E-08 0.0000E + 00

[Overall specifications]
Zoom ratio 70.00
Wide-angle end Mid-focus Telephoto end f 4.430 37.064 310.100
Fno 2.51999 5.81666 5.6272
ω 43.39058 6.11341 0.72895
Bf 0.400 0.400 0.400
Bf (Air) 5.899 3.357 0.942
TL 116.1281 140.7703 189.7467
TL (air) 116.3701 141.0123 189.9887

[Variable interval data]
Variable interval Wide-angle end Mid-focus Telephoto end
D7 0.75000 30.71122 94.88378
D15 47.52740 8.76826 1.87939
D23 2.92278 35.90870 20.00918
D26 5.00000 8.00000 18.01274
D29 5.25664 2.71478 0.30000

[Lens group data]
Group number Group initial surface Group focal length G1 1 119.50699
G2 8-9.30 300
G3 17 18.50000
G4 24 -39.35678
G5 27 31.99996

[Conditional expression]
Conditional Expression (1) (−f2) / ft = 0.030
Conditional Expression (2) AVE1Grpvd = 76.90
Conditional Expression (3) G1vd = 47.35
Conditional Expression (4) D12t / D12w = 126.51
Conditional Expression (5) β 2 t / β 2 w = 14.30
Conditional Expression (6) f3 / ft = 0.060

  It is understood from Table 2 that the zoom lens ZL2 according to the present example satisfies the conditional expressions (1) to (6).

  FIG. 4 shows various aberrations (spherical aberration, astigmatism, distortion, coma and lateral chromatic aberration) of the zoom lens ZL2 of the second embodiment at infinity shooting distance. Shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state.

  As is apparent from the respective aberration diagrams shown in FIG. 4, it is understood that the zoom lens ZL2 according to the second example has various aberrations well corrected and has excellent imaging performance.

Third Embodiment
The third embodiment will be described with reference to FIG. 5, FIG. 6 and Table 3. As shown in FIG. 5, the zoom lens ZL (ZL3) according to the third example 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 And a fourth lens group G4 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. Ru.

  The first lens group G1 is a cemented lens consisting of a negative meniscus lens L11 having a concave surface facing the image side and a biconvex positive lens L12 arranged in order from the object side along the optical axis, and a convex surface on the object side It consists of a positive meniscus lens L13 directed and a positive meniscus lens L14 convex on the object side.

  The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens L21 with a concave surface facing the image side, a biconcave negative lens L22, and a biconvex positive lens L23. It comprises a cemented lens and a negative meniscus lens L24 with a concave surface facing the object side.

  The third lens group G3 has a biconvex positive lens L31, a negative meniscus lens L32 with a concave surface facing the image side, and a positive meniscus with a convex surface facing the object side, which are arranged in order from the object side along the optical axis It comprises a cemented lens consisting of a lens L33 and a biconvex positive lens L34. Both surfaces of the biconvex positive lens L31 are aspheric.

  The fourth lens group G4 is composed of a cemented lens including a positive meniscus lens L41 having a convex surface facing the image side and a biconcave negative lens L42 arranged in order from the object side along the optical axis.

  The fifth lens group G5 is composed of a cemented lens including a biconvex positive lens L51 and a negative meniscus lens L52 having a concave surface facing the object side, which are arranged in order from the object side along the optical axis. The object side surface of the biconvex positive lens L51 is an aspheric surface.

  An aperture stop S is provided on the object side of the third lens group G3 for the purpose of adjusting the amount of light.

  A filter FL is provided on the image side of the fifth lens group G5. The filter FL is configured of a low pass filter, an infrared cut filter, or the like for cutting a spatial frequency higher than the limit resolution of the solid-state imaging device, such as a CCD disposed on the image plane I.

  The zoom lens ZL3 according to the present embodiment includes all the lenses from the first lens group G1 to the fifth lens group G5 so that the distance between the lens groups changes upon zooming from the wide-angle end state to the telephoto end state. Move the group. Specifically, the first lens group G1 is moved to the object side. The second lens group G2 is once moved to the image plane side, and then moved to the object side. The third lens group G3 is moved to the object side. The fourth lens group G4 is once moved to the image plane side, and then moved to the object side. The fifth lens group G5 is moved to the image plane side. The aperture stop S is moved to the object side integrally with the third lens group G3.

  Table 3 below shows values of respective items in the third embodiment. The surface numbers 1 to 32 in Table 3 correspond to the optical surfaces m1 to m32 shown in FIG. 5.

(Table 3)
[Lens specification]
Face number R D nd d d
Object ∞
1 291.9703 2.3000 1.7859 44.17
2 72.3111 7.4243 1.4370 95.10
3-1201.3878 0.1000
4 78.8924 6.4219 1.4978 82.57
5 1542.7728 0.1000
6 82.9135 5.2000 1.4978 82.57
7 31 11.2487 D7 (variable)
8 60.7024 1.0000 1.8830 40.66
9 12.9654 5.9446
10-22.2075 0.8000 1.7440 44.80
11 16.9140 3.7500 1.9229 20.88
12 -64.8769 1.7659
13-15.7953 0.7000 1.6958 55.52
14-45.5525 D14 (variable)
15 0.1 0.1000 (aperture S)
16 10.5140 2.9919 1.5533 71.68
* 17-58.4572 2.8910
* 18 30.8667 1.0000 1.9031 31.31
19 9.3737 1.7411
20 14.0809 1.0000 1.7859 44.17
21 17.6611 3.0000 1.4978 82.57
22-23.7336 D22 (variable)
23-558.9081 2.2109 1.5317 48.78
24 -37.3536 0.5000 1.4978 82.57
25 22.4761 D25 (variable)
26 37.6571 2.0000 1.5891 61.15
* 27 -20.0000 0.5000 1.7174 29.57
28-30.9522 D28 (variable)
29 0.2 0.2100 1.5168 63.88
30 0.8 0.8500
31 0.5 0.5000 1.5168 63.88
32 B Bf
Image plane ∞

[Aspheric surface data]
Face number κ A4 A6 A8 A10
17 0.2984 2.2126E-05-9.6783E-08 1.0853E-08 0.0000E + 00
18 1.0000 7.4554E-05 -4.8732E-07 1.4048E-08 -6.1745E-11
27 15.0166 -8.4847E-05 6.1404E-08 -7.2871E-12 0.0000E + 00

[Overall specifications]
Zoom ratio 78.22
Wide-angle end Mid-focus Telephoto end f 4.430 39.179 346.505
Fno 2.43455 4.13217 6.96915
ω 43.38805 5.81887 0.66236
Bf 0.400 0.400 0.400
Bf (air) 8.065 4.492 2.081
TL 115.1645 157.4796 199.5146
TL (air) 115.4065 157.7216 199.7566

[Variable interval data]
Variable interval Wide-angle end Mid-focus Telephoto end
D7 0.75000 59.34562 89.39655
D14 45.32590 12.31287 1.98552
D22 1.45649 18.75135 8.86102
D25 5.04939 8.04422 42.66202
D28 7.42269 3.84984 1.43902

[Lens group data]
Group number Group initial surface Group focal length G1 1 114.99999
G2 8-9.35558
G3 16 18.46138
G4 23-45.00007
G5 26 31.23415

[Conditional expression]
Conditional Expression (1) (-f2) / ft = 0.027
Conditional Expression (2) AVE1Grpvd = 76.10
Conditional Expression (3) G1vd = 44.17
Conditional Expression (4) D12t / D12w = 119.20
Conditional Expression (5) β2t / β2w = 13.15
Conditional Expression (6) f3 / ft = 0.053

  It is understood from Table 3 that the zoom lens ZL3 according to this example satisfies the conditional expressions (1) to (6).

  FIG. 6 shows various aberrations (spherical aberration, astigmatism, distortion, coma and lateral chromatic aberration) of the zoom lens ZL3 according to Example 3 at infinity shooting distance. Shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state.

  As apparent from the respective aberration diagrams shown in FIG. 6, it is understood that the zoom lens ZL3 according to the third example has various aberrations well corrected and has excellent imaging performance.

Fourth Embodiment
The fourth embodiment will be described with reference to FIG. 7, FIG. 8 and Table 4. As shown in FIG. 7, the zoom lens ZL (ZL4) according to the fourth example has a first lens group G1 with positive refractive power and negative refractive power, which are arranged in order from the object side along the optical axis And a fourth lens group G4 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. Ru.

  The first lens group G1 is a cemented lens consisting of a negative meniscus lens L11 having a concave surface facing the image side and a biconvex positive lens L12 arranged in order from the object side along the optical axis, and a convex surface on the object side It consists of a positive meniscus lens L13 directed and a positive meniscus lens L14 convex on the object side.

  The second lens group G2 includes a negative meniscus lens L21 having a concave surface facing the image side, a biconcave negative lens L22, and a biconvex positive lens L23. The negative meniscus lens L24 has a concave surface facing the object side.

  The third lens group G3 is a biconvex positive lens L31, a biconcave negative lens L32, and a positive meniscus lens L33 having a convex surface facing the object side, which are arranged in order from the object side along the optical axis. And a cemented lens including a convex positive lens L34. Both surfaces of the biconvex positive lens L31 are aspheric.

  The fourth lens group G4 includes a cemented lens including a negative meniscus lens L41 having a concave surface facing the image side and a positive meniscus lens L42 having a concave surface facing the object side, which are arranged in order from the object side along the optical axis. Ru.

  The fifth lens group G5 is composed of a cemented lens including a biconvex positive lens L51 and a negative meniscus lens L52 having a concave surface facing the object side, which are arranged in order from the object side along the optical axis. The object side surface of the biconvex positive lens L51 is an aspheric surface.

  An aperture stop S is provided on the object side of the third lens group G3 for the purpose of adjusting the amount of light.

  A filter FL is provided on the image side of the fifth lens group G5. The filter FL is configured of a low pass filter, an infrared cut filter, or the like for cutting a spatial frequency higher than the limit resolution of the solid-state imaging device, such as a CCD disposed on the image plane I.

  The zoom lens ZL4 according to the present embodiment includes all lenses from the first lens group G1 to the fifth lens group G5 so that the distance between the lens groups changes upon zooming from the wide-angle end state to the telephoto end state. Move the group. Specifically, the first lens group G1 is moved to the object side. The second lens group G2 is moved to the image plane side. The third lens group G3 is moved to the object side. The fourth lens group G4 is once moved to the object side, and then moved to the image plane side. The fifth lens group G5 is moved to the image plane side. The aperture stop S is moved to the object side integrally with the third lens group G3.

  Table 4 below shows values of respective items in the fourth embodiment. The surface numbers 1 to 33 in Table 4 correspond to the optical surfaces m1 to m33 shown in FIG. 7.

(Table 4)
[Lens specification]
Face number R D nd d d
Object ∞
1 208.3815 2.3000 1.8044 39.61
2 71.5047 7.7255 1.4370 95.10
3-765.8864 0.1000
4 74.8004 6.0964 1.4978 82.57
5 465.0253 0.1000
6 86.8705 5.2000 1.4978 82.57
7 390.6162 D7 (variable)
8 101.8391 1.0000 1.7880 47.35
9 13.9500 5.7000
10-26.1620 0.8000 1.8348 42.73
11 19.4555 0.1000
12 19.0787 3.2308 1.9229 20.88
13 -66.5101 1.1878
14-17.6024 0.7000 1.6958 55.52
15-108.5090 D15 (variable)
16 0.1 0.1000 (aperture S)
* 17 10.4010 3.1500 1.5533 71.68
* 18-28.5808 2.0669
19 -293.1983 1.0000 1.8830 40.66
20 10.3933 1.5000
21 16.1238 1.0000 1.7859 44.17
22 34.1223 3.0000 1.4978 82.57
23-14.4033 D23 (variable)
24 743.7882 1.5000 1.5317 48.78
25 8.1699 1.0000 1.4978 82.57
26 16.6750 D26 (variable)
* 27 28.4599 2.0005 1.5891 61.25
28 -20.0000 0.5000 1.7174 29.57
29-31.8276 D29 (variable)
30 0.2 0.2100 1.5168 63.88
31 0.8 0.8500
32 0.5 0.5000 1.5168 63.88
33 B Bf
Image plane ∞

[Aspheric surface data]
Face number κ A4 A6 A8 A10
17 0.7787 -4.4127E-05 2.5417E-07 6.1315E-09 0.0000E + 00
18 1.0000 1.2195E-04 -4.0857E-08 7.2014E-09 -6.1745E-11
27 -34.1326 1.0673E-04 -3.2846E-06 5.1727E-08 0.0000E + 00

[Overall specifications]
Zoom ratio 67.15
Wide-angle end Mid-focus Telephoto end f 4.430 35.716 297.466
Fno 2.60507 4.87201 5.85857
ω 43.06494 6.33115 0.76345
Bf 0.400 0.400 0.400
Bf (air) 6.181 1.642 0.950
TL 119.7472 161.2222 174.7740
TL (air) 119.9892 161.4442 175.0160

[Variable interval data]
Variable interval Wide-angle end Mid-focus Telephoto end
D7 0.75000 53.27134 81.00337
D15 49.83.252 21.16730 1.00000
D23 2.84198 6.26878 18.82770
D26 8.01801 26.71375 20.84323
D29 5.53948 1.00000 0.30769

[Lens group data]
Group number Group initial surface Group focal length G1 101.05751
G2 8-8.96757
G3 17 17.52950
G4 24 -30.00001
G5 27 27.53859

[Conditional expression]
Conditional Expression (1) (−f2) / ft = 0.030
Conditional Expression (2) AVE1Grpvd = 74.96
Conditional Expression (3) G1vd = 39.61
Conditional Expression (4) D12t / D12w = 108.00
Conditional Expression (5) β2t / β2w = 12.35
Conditional Expression (6) f3 / ft = 0.059

  From Table 4, it can be seen that the zoom lens ZL4 according to this example satisfies the conditional expressions (1) to (6).

  FIG. 8 shows various aberrations (spherical aberration, astigmatism, distortion, coma and chromatic aberration of magnification) of the zoom lens ZL4 according to Example 4 at infinity shooting distance. Shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state.

  As apparent from the respective aberration diagrams shown in FIG. 8, it is understood that the zoom lens ZL4 according to the fourth example has various aberrations well corrected and has excellent imaging performance.

Fifth Embodiment
The fifth embodiment will be described with reference to FIG. 9, FIG. 10 and Table 5. In the zoom lens ZL (ZL5) according to the fifth example, as shown in FIG. 9, a first lens group G1 having positive refractive power and negative refractive power are arranged in order from the object side along the optical axis And a fourth lens group G4 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. Ru.

  The first lens group G1 is a cemented lens consisting of a negative meniscus lens L11 having a concave surface facing the image side and a biconvex positive lens L12 arranged in order from the object side along the optical axis, and a convex surface on the object side It consists of a positive meniscus lens L13 directed and a positive meniscus lens L14 convex on the object side.

  The second lens group G2 includes a negative meniscus lens L21 having a concave surface facing the image side, a negative meniscus lens L22 having a concave surface facing the object side, and a biconvex positive lens. It comprises a lens L23 and a biconcave negative lens L24.

  The third lens group G3 includes a positive lens L31 having a convex surface facing the object, a negative meniscus lens L32 having a concave surface facing the image, and a concave surface facing the image. It is composed of a cemented lens consisting of a negative meniscus lens L33 and a biconvex positive lens L34. Both surfaces of the biconvex positive lens L31 are aspheric.

  The fourth lens group G4 is composed of a cemented lens including a positive meniscus lens L41 having a convex surface facing the image side and a biconcave negative lens L42 arranged in order from the object side along the optical axis.

  The fifth lens group G5 is composed of a cemented lens including a biconvex positive lens L51 and a negative meniscus lens L52 having a concave surface facing the object side, which are arranged in order from the object side along the optical axis. The object side surface of the biconvex positive lens L51 is an aspheric surface.

  An aperture stop S is provided on the object side of the third lens group G3 for the purpose of adjusting the amount of light.

  A filter FL is provided on the image side of the fifth lens group G5. The filter FL is configured of a low pass filter, an infrared cut filter, or the like for cutting a spatial frequency higher than the limit resolution of the solid-state imaging device, such as a CCD disposed on the image plane I.

  The zoom lens ZL5 according to the present embodiment includes all lenses from the first lens group G1 to the fifth lens group G5 so that the distance between the lens groups changes upon zooming from the wide-angle end state to the telephoto end state. Move the group. Specifically, the first lens group G1 is moved to the object side. The second lens group G2 is once moved to the image plane side, and then moved to the object side. The third lens group G3 is moved to the object side. The fourth lens group G4 is moved to the object side. The fifth lens group G5 is moved to the image plane side. The aperture stop S is moved to the object side integrally with the third lens group G3.

  Table 5 below shows values of respective items in the fifth example. The surface numbers 1 to 33 in Table 5 correspond to the optical surfaces m1 to m33 shown in FIG.

(Table 5)
[Lens specification]
Face number R D nd d d
Object ∞
1 263.0063 2.3000 1.7859 44.17
2 82.7549 7.0000 1.4370 95.10
3-1109.1351 0.1000
4 85.5748 5.8000 1.4370 95.10
5 520.4380 0.1000
6 84.6851 5.0982 1.4978 82.57
7 302.4541 D7 (variable)
8 49.5072 1.0000 1.8830 40.66
9 11.5546 5.7000
10-21.8668 0.8000 1.8348 42.73
11-21914.
12 28.1612 3.7500 1.9229 20.88
13 -46.2757 1.5083
14-19.3983 0.7000 1.6958 55.46
15 259.7592 D15 (variable)
16 0.1 0.1000 (aperture S)
* 17 11.6667 2.7000 1.5533 71.68
* 18 8376.3479 2.0436
19 18.0472 1.0000 1.9037 31.31
20 11.0864 2.0000
21 17.1967 0.5000 1.7995 42.09
22 10.6441 3.0000 1.4978 82.57
23-28.9001 D23 (variable)
24-105.3136 2.4205 1.5317 48.78
25 -17.9207 0.5000 1.4978 82.57
26 22.9810 D26 (variable)
* 27 29.1256 2.0436 1.5891 61.25
28 -20.0000 0.5000 1.7174 29.57
29 -45.0948 D29 (variable)
30 0.2 0.2100 1.5168 63.88
31 0.8 0.8500
32 0.5 0.5000 1.5168 63.88
33 B Bf
Image plane ∞

[Aspheric surface data]
Face number κ A4 A6 A8 A10
17 0.9914 -2.7993E-05 -4.2955E-07 1.1909E-08 0.0000E + 00
18 1.0000 5.0164E-05 -4.0760E-07 1.8325E-08 -6.1745E-11
27 -3.5175 1.1021E-05 -2.3098E-07 1.6357E-08 0.0000E +00

[Overall specifications]
97.00 zoom ratio
Wide-angle end Mid-focus Telephoto end f 4.430 43.630 429.712
Fno 2.70160 5.08497 8.28574
ω 43.39124 5.27441 0.53600
Bf 0.400 0.400 0.400
Bf (air) 10.972 1.642 1.623
TL 130.7843 173.5863 217.4697
TL (air) 131.0263 173.8283 217.7117

[Variable interval data]
Variable interval Wide-angle end Mid-focus Telephoto end
D7 0.75000 68.26231 102.51459
D15 60.14750 19.05527 3.07934
D23 1.33023 16.10976 11.63827
D26 5.74536 16.66072 46.75849
D29 10.3295 1.00000 0.98126

[Lens group data]
Group number Group initial surface Group focal length G1 1 129.99999
G2 8 -10.74275
G3 17 20.08 616
G4 24 -40.00002
G5 27 34.00000

[Conditional expression]
Conditional Expression (1) (-f2) / ft = 0.025
Conditional Expression (2) AVE1Grpvd = 79.24
Conditional Expression (3) G1vd = 44.17
Conditional Expression (4) D12t / D12w = 136.69
Conditional Expression (5) β 2 t / β 2 w = 14.30
Conditional Expression (6) f3 / ft = 0.047

  It is understood from Table 5 that the zoom lens ZL5 according to this example satisfies the conditional expressions (1) to (6).

  FIG. 10 shows various aberrations (spherical aberration, astigmatism, distortion, coma and lateral chromatic aberration) of the zoom lens ZL5 according to Example 5 at infinity of distances. Shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state.

  As apparent from the respective aberration diagrams shown in FIG. 10, it is understood that the zoom lens ZL5 according to the fifth example has various aberrations well corrected and has excellent imaging performance.

Sixth Embodiment
A sixth embodiment will be described using FIG. 11, FIG. 12 and Table 6. The zoom lens ZL (ZL6) according to the sixth example has a first lens group G1 with positive refractive power and negative refractive power, which are arranged in order from the object side along the optical axis, as shown in FIG. , A third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, a fifth lens group G5 having a positive refractive power, and a positive lens And a sixth lens group G6 having a refractive power.

  The first lens group G1 is a cemented lens consisting of a negative meniscus lens L11 having a concave surface facing the image side and a biconvex positive lens L12 arranged in order from the object side along the optical axis, and a convex surface on the object side It consists of a positive meniscus lens L13 directed and a positive meniscus lens L14 convex on the object side.

  The second lens group G2 includes a negative meniscus lens L21 having a concave surface facing the image side, a biconcave negative lens L22, and a biconvex positive lens L23. It consists of a biconcave negative lens L24.

  The third lens group G3 includes, in order from the object side along the optical axis, a positive meniscus lens L31 with a convex surface facing the object side, a negative meniscus lens L32 with a concave surface facing the image side, and a concave surface with the image side It is configured of a cemented lens including a negative meniscus lens L33 directed and a positive lens L34 having a biconvex shape. Both surfaces of the biconvex positive lens L31 are aspheric.

  The fourth lens group G4 is composed of a cemented lens including a positive meniscus lens L41 having a convex surface facing the image side and a biconcave negative lens L42 arranged in order from the object side along the optical axis.

  The fifth lens group G5 is composed of a cemented lens including a biconvex positive lens L51 and a negative meniscus lens L52 having a concave surface facing the object side, which are arranged in order from the object side along the optical axis. The object side surface of the biconvex positive lens L51 is an aspheric surface.

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

  An aperture stop S is provided on the object side of the third lens group G3 for the purpose of adjusting the amount of light.

  A filter FL is provided on the image side of the sixth lens group G6. The filter FL is configured of a low pass filter, an infrared cut filter, or the like for cutting a spatial frequency higher than the limit resolution of the solid-state imaging device, such as a CCD disposed on the image plane I.

  The zoom lens ZL6 according to the present embodiment includes all lenses from the first lens group G1 to the sixth lens group G6 so that the distance between the lens groups changes upon zooming from the wide-angle end state to the telephoto end state. Move the group. Specifically, the first lens group G1 is moved to the object side. The second lens group G2 is moved to the image plane side. The third lens group G3 is moved to the object side. The fourth lens group G4 is moved to the object side. The fifth lens group G5 is moved to the image plane side. The sixth lens group G6 is moved to the object side. The aperture stop S is moved to the object side integrally with the third lens group G3.

  The following Table 6 shows values of respective items in the sixth embodiment. The surface numbers 1 to 35 in Table 6 correspond to the optical surfaces m1 to m35 shown in FIG.

(Table 6)
[Lens specification]
Face number R D nd d d
Object ∞
185.9259 2.3000 1.900433 37.37
2 93.7725 7.0058 1.437001 95.10
3-2966.2960 0.1000
4 90.7425 5.1630 1.437001 95.10
5 576.7002 0.1000
6 91.5818 4.5000 1.497820 82.57
7 271.0724 D7 (variable)
8 85.5699 1.0000 1.883000 40.66
9 13.7260 8.0241
10-25.3126 0.8000 1.834810 42.73
11 100.2702 0.1000
12 32.0359 3.4979 1.922860 20.88
13 -40.2295 1.9112
14 -20.0004 0.7000 1.696802 55.46
15 534.4 663 D15 (variable)
16 0.1 0.1000 (aperture S)
* 17 11.8578 2.7000 1.553319 71.68
* 18 358.4613 2.0000
19 15.5677 1.0000 1.903658 31.31
20 11.2909 1.5000
21 18.2012 0.5000 1.799520 42.09
22 9.1742 3.0523 1.497820 82.57
23-39.5155 D23 (variable)
24 -147.7108 2.5218 1.53172 48.78
25-28.3514 0.5000 1.49782 82.57
26 21.1401 D26 (variable)
* 27 38.0765 2.0000 1.5891 3 61.25
28 -20.0000 0.5000 1.71736 29.57
29 -34.6793 D29 (variable)
30 -35.0000 1.1441 1.49782 82.57
31 -30.0000 D31 (variable)
32 0.2 0.2100 1.51680 63.88
33 0.8 0.8500
34 0.5 0.5000 1.51680 63.88
35 ∞ Bf
Image plane ∞

[Aspheric surface data]
Face number κ A4 A6 A8 A10
17 1.0048 -2.5489E-05 -3.9473E-07 9.6614E-09 0.0000E + 00
18 1.0000 3.9703E-05 -3.5578E-07 1.5790E-08 -6.1745E-11
27 1.0000 -2.7472E-05 6.8463E-07 -1.6469E-08 0.0000E + 00

[Overall specifications]
97.00 zoom ratio
Wide-angle end Mid-focus Telephoto end f 4.430 43.631 429.720
Fno 2.92486 5.69847 8.77338
ω 43.21864 5.26157 0.53559
Bf 0.400 0.400 0.400
Bf (Air) 9.938 1.860 0.942
TL 138.4644 180. 5524 212.5374
TL (air) 138.7064 180.9944 212.7794

[Variable interval data]
Variable interval Wide-angle end Mid-focus Telephoto end
D7 0.75000 67.31512 100.20497
D15 65.74525 22.59867 1.00000
D23 2.75173 14.55177 30.65337
D26 5.38192 20.23914 24.82268
D29 9.29589 1.21841 0.30000
D31 0.10000 0.37749 1.09589

[Lens group data]
Group number Group initial surface Group focal length G1 1 129.99999
G2 8 -10.65737
G3 17 21.00000
G4 24 -38.30835
G5 27 33.99853
G6 30 392.02507

[Conditional expression]
Conditional Expression (1) (-f2) / ft = 0.025
Conditional Expression (2) AVE1Grpvd = 77.54
Conditional Expression (3) G1vd = 37.37
Conditional Expression (4) D12t / D12w = 133.616
Conditional Expression (5) β2t / β2w = 12.35
Conditional Expression (6) f3 / ft = 0.049

  From Table 6, it can be seen that the zoom lens ZL6 according to this example satisfies the conditional expressions (1) to (6).

  FIG. 12 shows various aberrations (spherical aberration, astigmatism, distortion, coma and lateral chromatic aberration) of the zoom lens ZL6 according to the sixth example, at infinity. Shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state.

  As apparent from the respective aberration diagrams shown in FIG. 12, it is understood that the zoom lens ZL6 according to the sixth example has various aberrations well corrected and has excellent imaging performance.

  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.

  For example, in the above embodiment, the five-group and six-group configuration is shown, but the invention can be applied to other group configurations. Also, 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. In addition, 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 zoom lens ZL according to the present embodiment, a single or a plurality of lens groups or a partial lens group may be moved in the optical axis direction to provide a focusing lens group for focusing from an infinite distance object to a near distance object. . This focusing lens group can also be applied to auto focusing, and is also suitable for motor driving (using an ultrasonic motor or the like) for auto focusing. In particular, it is preferable to set the fourth lens group G4 as a focusing lens group. In addition, the fifth lens group G5 may be a focusing lens group. Alternatively, focusing can be performed by simultaneously moving the fourth lens group G4 and the fifth lens group G5.

  In the zoom lens ZL according to the present embodiment, the lens group or the partial lens group is moved so as to have a component in the direction perpendicular to the optical axis, or rotationally moved (rocked) in the in-plane direction including the optical axis. The vibration reduction lens group may be configured to correct an image blur caused by camera shake. In particular, it is preferable to set the third lens group G3 as a vibration reduction lens group.

  In the zoom lens ZL according to the present embodiment, the lens surface may be formed as a spherical surface, a flat surface, or an aspheric 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 zoom lens ZL according to the present embodiment, the aperture stop S is preferably disposed in the vicinity of the third lens group G3, but the lens frame substitutes its role without providing a member as the aperture stop. May be

  In the zoom lens ZL according to the present embodiment, each lens surface may be provided with an anti-reflection film having high transmittance over a wide wavelength range in order to reduce flare and ghost and achieve high optical performance with high contrast. .

ZL (ZL1 to ZL6) Zoom lens G1 first lens group G2 second lens group G3 third lens group G4 fourth lens group G5 fifth lens group G6 sixth lens group S aperture stop FL filter I field of view CAM digital still camera (Optical equipment)

Claims (10)

The first lens group having positive refractive power, the second lens group having negative refractive power, the third lens group having positive refractive power, and the third lens group having positive refractive power, which are arranged in order from the object side along the optical axis The fourth lens group having a refractive power and the fifth lens group having a positive refractive power are used to change magnification by changing the distance between the lens groups,
The first lens group is composed of three or more lenses.
The fifth lens group moves toward the image plane side during zooming from the wide-angle end state to the telephoto end state,
A zoom lens characterized by satisfying the following conditional expression.
0.020 <(-f2) / ft <0.031
74.00 <AVE1Grpvd <80.00
36.00 <G1 vd <48.00
108.00 ≦ D12t / D12w <140.00
However,
f2: focal length of the second lens group in the telephoto end state,
ft: focal length of the entire system at the telephoto end state,
AVE1Grpvd: average of Abbe number based on the d-line of the lens in the first lens group,
G1vd: Abbe number based on the d-line of the lens disposed closest to the object in the first lens group
D12t: air gap between the first lens group and the second lens group in the telephoto end state,
D12w: Air space between the first lens group and the second lens group in the wide-angle end state. The first lens group having positive refractive power, the second lens group having negative refractive power, the third lens group having positive refractive power, and the third lens group having positive refractive power, which are arranged in order from the object side along the optical axis The fourth lens group having a refractive power and the fifth lens group having a positive refractive power are used to change magnification by changing the distance between the lens groups,
The first lens group is composed of three or more lenses.
The fifth lens group moves toward the image plane side during zooming from the wide-angle end state to the telephoto end state,
A zoom lens characterized by satisfying the following conditional expression.
0.020 <(-f2) / ft <0.031
74.00 <AVE1Grpvd <80.00
36.00 <G1 vd <48.00
12.34 <β2t / β2w <14.40
However,
f2: focal length of the second lens group in the telephoto end state,
ft: focal length of the entire system in the telephoto end state,
AVE1Grpvd: average of Abbe number based on the d-line of the lens in the first lens group,
G1vd: Abbe number based on the d-line of the lens disposed closest to the object in the first lens group
β2t: Magnification of the second lens unit in the telephoto end state
β2 w: Magnification of the second lens group in the wide-angle end state. The first lens group having positive refractive power, the second lens group having negative refractive power, the third lens group having positive refractive power, and the third lens group having positive refractive power, which are arranged in order from the object side along the optical axis The fourth lens group having a refractive power and the fifth lens group having a positive refractive power are used to change magnification by changing the distance between the lens groups,
The first lens group is composed of three or more lenses.
The fifth lens group moves toward the image plane side during zooming from the wide-angle end state to the telephoto end state,
A zoom lens characterized by satisfying the following conditional expression.
0.020 <(-f2) / ft <0.031
108.00 ≦ D12t / D12w ≦ 137.01
However,
f2: focal length of the second lens group in the telephoto end state,
ft: focal length of the entire system in the telephoto end state,
D12t: air gap between the first lens group and the second lens group in the telephoto end state,
D12w: Air space between the first lens group and the second lens group in the wide-angle end state. The zoom lens according to claim 2 , wherein the following conditional expression is satisfied.
100.00 <D12t / D12w <140.00
However,
D12t: air gap between the first lens group and the second lens group in the telephoto end state,
D12w: Air space between the first lens group and the second lens group in the wide-angle end state. The zoom lens according to claim 3, characterized by satisfying the following conditional expression.
12.34 <β2t / β2w <14.40
However,
β2t: Magnification of the second lens unit in the telephoto end state
β2 w: Magnification of the second lens group in the wide-angle end state. The zoom lens according to any one of claims 1 to 5 , wherein the following conditional expression is satisfied.
0.04 <f3 / ft <0.06
However,
f3: The focal length of the third lens unit in the telephoto end state. The third lens group, one from the object side along the optical axis arranged in a forward, a positive lens, a negative lens, a negative lens, of claims 1 to 6, characterized in that it is composed of a positive lens The zoom lens according to any one of the items. The zoom lens according to any one of claims 1 to 7 , wherein the third lens group includes at least one aspheric lens. An optical apparatus comprising the zoom lens according to any one of claims 1 to 8 . The first lens group having positive refractive power, the second lens group having negative refractive power, the third lens group having positive refractive power, and the third lens group having positive refractive power, which are arranged in order from the object side along the optical axis A manufacturing method of a zoom lens having a fourth lens group having a refractive power and a fifth lens group having a positive refractive power, and changing an interval of each lens group to perform zooming.
The first lens group is composed of three or more lenses.
The fifth lens group moves toward the image plane side during zooming from the wide-angle end state to the telephoto end state,
In order to satisfy the following conditional expression,
A manufacturing method of a zoom lens characterized by arranging each lens in a lens barrel.
0.020 <(-f2) / ft <0.031
74.00 <AVE1Grpvd <80.00
36.00 <G1 vd <48.00
108.00 ≦ D12t / D12w <140.00
However,
f2: focal length of the second lens group in the telephoto end state,
ft: focal length of the entire system at the telephoto end state,
AVE1Grpvd: average of Abbe number based on the d-line of the lens in the first lens group,
G1vd: Abbe number based on the d-line of the lens disposed closest to the object in the first lens group
D12t: air gap between the first lens group and the second lens group in the telephoto end state,
D12w: Air space between the first lens group and the second lens group in the wide-angle end state.

Images