JP5333896B2 - Zoom lens, optical apparatus having the same, and vibration isolation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a zoom lens capable of achieving camera shake correction, having little performance degradation though high variable power is contrived, and setting appropriate refractive power, and optical equipment having the same and a vibration-proofing method. <P>SOLUTION: The zoom lens includes, in order from an object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, and a fourth lens group G4 having positive refractive power, wherein an interval between the respective lens groups changes when varying power. The lens group G3 has a thirty-first lens group G31 having positive refractive power, and a thirty-second lens group G32 having negative refractive power, and moves the thirty-second lens group G32 to have a component in a direction orthogonal to an optical axis. Assuming that a moving amount of the lens group G1 when varying the power is X1, a focal length of the lens entire system in a wide angle end state is fw, a focal length of the second lens group G2 is f2, and a back focus at the wide angle end state is Bfw, they satisfy a condition shown by following expressions; 2.6&lt;X1/fw&lt;4.2 and 0.430&lt;(-f2)/Bfw&lt;0.540. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a zoom lens, an optical apparatus having the same, and a vibration isolation method.

Due to recent advances in optical design technology and manufacturing technology, zoom lenses have been reduced in size and increased in magnification. However, the increase in the focal length at the telephoto end due to high zooming has made the camera shake problem more prominent. Regarding this camera shake, zoom lenses having various camera shake correction functions have been proposed (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 2003-140048

  However, the conventional zoom lens having the camera shake correction function has a problem that the optical performance is significantly deteriorated when the zoom ratio is increased.

  The present invention has been made in view of such a problem, and performs image shift by an optical system that can move so as to have a component orthogonal to the optical axis, enables camera shake correction, and achieves high zooming. An object of the present invention is to provide a zoom lens having an appropriate refractive power, an optical apparatus having the same, and an image stabilization method so as to reduce the deterioration of the performance while being achieved.

In order to achieve such an object, the zoom lens of the present invention includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a positive refraction arranged in order from the object side. The fourth lens group having a positive refracting power and the fourth lens group having a positive refracting power substantially comprise four lens groups, and the distance between the lens groups is changed during zooming from the wide-angle end state to the telephoto end state. The third lens group includes a positive lens group having a positive refractive power and a negative lens group having a negative refractive power arranged in order from the object side, and the negative lens group is defined as an optical axis. The negative lens group includes a cemented lens of a biconcave negative lens and a positive lens, and the first lens at the time of zooming from the wide-angle end state to the telephoto end state. The movement amount of the group is X1, and the focal length of the entire lens system in the wide-angle end state is fw. When the focal length of the second lens group is f2 and the back focus in the wide-angle end state is Bfw, the following expressions 2.6 <X1 / fw <4.2 and 0.430 <(− f2) / Bfw < The condition of 0.540 is satisfied.

The zoom lens according to the present invention includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power, which are arranged in order from the object side. And a fourth lens group having a positive refractive power, and substantially consists of four lens groups, and the distance between the lens groups changes upon zooming from the wide-angle end state to the telephoto end state. The group includes a positive lens group having a positive refractive power and a negative lens group having a negative refractive power, which are arranged in order from the object side, and the negative lens group has a component orthogonal to the optical axis. The negative lens group has a cemented lens of a biconcave negative lens and a positive lens, and the amount of movement of the first lens group at the time of zooming from the wide-angle end state to the telephoto end state is X1. The focal length of the entire lens system in the wide-angle end state is fw, and the focal length of the first lens group is Distance and f1, the focal length of the third lens group and the f3, the following conditional expression is satisfied: 2.6 <X1 / fw <4.2 and 2.20 <f1 / f3 ≦ 2.44.

  The negative lens group preferably has at least one aspherical surface.

  Further, it is preferable that the fourth lens group has a positive lens component closest to the object side, and the positive lens component has an aspherical surface.

  In zooming from the wide-angle end state to the telephoto end state, it is preferable that the first lens group, the third lens group, and the fourth lens group move in the object direction.

  Further, when zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group increases, and the distance between the second lens group and the third lens group decreases. It is preferable that the distance between the third lens group and the fourth lens group changes.

  In addition, it is preferable that an air interval between the third lens group and the fourth lens group in the wide-angle end state is larger than an air interval between the third lens group and the fourth lens group in the telephoto end state.

  The optical apparatus of the present invention has the zoom lens described above.

According to the zoom lens stabilization method of the present invention, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens having a positive refractive power, which are arranged in order from the object side. An anti-vibration method for a zoom lens comprising substantially four lens groups by a lens group and a fourth lens group having a positive refractive power, and each lens during zooming from a wide-angle end state to a telephoto end state The third lens group includes a positive lens group having a positive refractive power and a negative lens group having a negative refractive power, which are arranged in order from the object side. The negative lens group The negative lens group includes a cemented lens of a biconcave negative lens and a positive lens, and is used for zooming from the wide-angle end state to the telephoto end state. The amount of movement of the first lens unit is X1, and the focal length of the entire lens system in the wide-angle end state Is fw, the focal length of the second lens group is f2, and the back focus in the wide-angle end state is Bfw, the following expressions 2.6 <X1 / fw <4.2 and 0.430 <(− f2) /Bfw<0.540 is satisfied.

The zoom lens stabilization method of the present invention has 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. An anti-vibration method for a zoom lens comprising substantially four lens groups by a third lens group and a fourth lens group having a positive refractive power, in zooming from a wide-angle end state to a telephoto end state The interval between the lens groups is changed, and the third lens group includes a positive lens group having a positive refractive power and a negative lens group having a negative refractive power, which are arranged in order from the object side. The lens group is moved so as to have a component orthogonal to the optical axis, and the negative lens group includes a cemented lens of a biconcave negative lens and a positive lens, and is capable of zooming from the wide-angle end state to the telephoto end state. The movement amount of the first lens unit at the time is X1, and the entire lens system in the wide-angle end state is When the point distance is fw, the focal length of the first lens group is f1, and the focal length of the third lens group is f3, the following expressions 2.6 <X1 / fw <4.2 and 2.20 < The condition of f1 / f3 ≦ 2.44 is satisfied.

  According to the present invention, image shift is performed by an optical system that can move so as to have a component orthogonal to the optical axis, image stabilization is possible, and it is appropriate to reduce performance deterioration while achieving high zooming. A zoom lens having an appropriate refractive power, an optical apparatus having the same, and a vibration isolation method can be provided.

  Hereinafter, preferred embodiments will be described with reference to the drawings. As shown in FIG. 1, the zoom lens according to the present embodiment includes a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a positive lens arranged in order from the object side. The first lens group G1 and the second lens group at the time of zooming from the wide-angle end state to the telephoto end state have a third lens group G3 having a refractive power of 4 and a fourth lens group G4 having a positive refractive power. The distance between G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 changes, and the third lens group G3 And a thirty-first lens group G31 having a positive refractive power and a thirty-second lens group G32 having a negative refractive power, arranged in order from the object side, and the thirty-second lens group G32 is a component orthogonal to the optical axis. To correct the image plane when camera shake occurs. .

  The third lens group G3 is suitable for incorporating an anti-vibration mechanism because the lens diameter can be reduced as compared with other lens groups. Therefore, even if an anti-vibration mechanism is incorporated in the lens barrel, an increase in the size of the lens barrel can be avoided. The third lens group G3 further includes a thirty-first lens group G31 having a positive refractive power and a thirty-second lens group G32 having a negative refractive power. The thirty-second lens group G32 is a lens group for image stabilization. Therefore, it is possible to reduce the size of the vibration isolation mechanism and reduce the mass of the vibration isolation lens group. Further, by setting the third lens group G3 to have such a refractive power distribution, the imaging performance when the anti-vibration thirty-second lens group G32 is moved so as to have a component perpendicular to the optical axis. Can be reduced.

  In this embodiment, based on the above configuration, the movement amount of the first lens unit at the time of zooming from the wide-angle end state to the telephoto end state is X1, and the focal length of the entire lens system in the wide-angle end state Is set to fw, the focal length of the second lens group is set to f2, and the back focus in the wide-angle end state is set to Bfw, the conditions of the following expressions (1) and (2) are satisfied. The sign of the movement amount X1 is positive when the position of the first lens group G1 in the telephoto end state is located in the object direction from the origin with the position on the optical axis in the wide-angle end state of the first lens group G1 as the origin. And

2.6 <X1 / fw <4.2 (1)
0.430 <(− f2) / Bfw <0.540 (2)

  Conditional expression (1) is a conditional expression that defines an appropriate amount of movement X1 of the first lens group G1 when zooming from the wide-angle end state to the telephoto end state in order to ensure a high magnification. If the upper limit of conditional expression (1) is exceeded, the amount of movement of the first lens group G1 with respect to zooming increases, and the amount of light in the telephoto end state decreases. As a result, the overall length and diameter of the zoom lens increase, making it difficult to put it into practical use. Moreover, since the fluctuation | variation of spherical aberration increases, it is not preferable. On the other hand, if the lower limit value of conditional expression (1) is not reached, the amount of movement of the first lens group G1 with respect to zooming will decrease too much, and the power of the first lens group G1 will be made relatively strong, or another lens will be used. This is not preferable because a zooming effect in the lens group is required, and the image plane variation due to zooming and the spherical aberration in the telephoto end state are significantly deteriorated.

  In the zoom lens according to the present embodiment, it is preferable to set the upper limit value of conditional expression (1) to 3.7 in order to ensure the effect. In the zoom lens according to the present embodiment, it is preferable to set the upper limit of conditional expression (1) to 3.5 in order to ensure the effect. Furthermore, in the zoom lens according to the present embodiment, it is preferable to set the upper limit value of conditional expression (1) to 3.3 in order to ensure the effect. In the zoom lens according to the present embodiment, it is preferable to set the lower limit of conditional expression (1) to 2.7 in order to make the effect more reliable.

  The conditional expression (2) is a conditional expression that defines the focal length f2 of the second lens group G2 with respect to the back focus Bfw in the wide-angle end state. If the upper limit value of conditional expression (2) is exceeded, the amount of light at the wide-angle end is reduced. Further, it is difficult to simultaneously correct the coma aberration in the wide-angle end state, the spherical aberration in the telephoto end state, and the fluctuation of the field curvature at the time of camera shake correction. On the other hand, if the lower limit of conditional expression (2) is not reached, the refractive power of the second lens group G2 becomes relatively strong, and astigmatism and field curvature in the wide-angle end state are significantly deteriorated, which is not preferable.

  In the zoom lens according to the present embodiment, it is preferable to set the upper limit value of conditional expression (2) to 0.480 in order to ensure the effect. In the zoom lens of this embodiment, it is preferable to set the lower limit value of conditional expression (2) to 0.435 in order to make the effect more reliable.

  Further, in the present embodiment, based on the above configuration, the amount of movement of the first lens group at the time of zooming from the wide-angle end state to the telephoto end state is X1, and the focal length of the entire lens system in the wide-angle end state Is fw, the focal length of the first lens group is f1, and the focal length of the third lens group is f3, the conditions of the following expressions (1) and (3) are satisfied (the conditional expression ( Since 1) has been described above, the description thereof is omitted here.

2.6 <X1 / fw <4.2 (1)
2.20 <f1 / f3 <2.85 (3)

  The conditional expression (3) is a conditional expression that defines an appropriate range of the focal length f1 of the first lens group G1, which is suitable for ensuring the back focus and imaging performance. If the upper limit value of conditional expression (3) is exceeded, the amount of light in the telephoto end state is reduced. In addition, the overall length and diameter of the zoom lens increase, making it difficult to put to practical use. On the other hand, if the lower limit value of conditional expression (3) is not reached, the back focus is shortened and the imaging performance in the telephoto end state, in particular, spherical aberration is deteriorated.

  In the zoom lens according to the present embodiment, it is preferable to set the upper limit value of conditional expression (3) to 2.70 in order to ensure the effect. In the zoom lens of this embodiment, it is preferable to set the lower limit value of conditional expression (3) to 2.35 in order to make the effect more reliable.

  In the present embodiment, the thirty-second lens group G32 preferably has a cemented lens made up of a biconcave negative lens and a positive lens. As a result, it is possible to reduce fluctuations in image plane chromatic aberration when the thirty-second lens group G32 is decentered for image stabilization.

  In the present embodiment, it is preferable that the thirty-second lens group G32 has at least one aspheric surface. Thereby, the fluctuation of the decentration coma aberration when the thirty-second lens group G32 is decentered can be reduced for image stabilization.

  In the present embodiment, it is preferable that the fourth lens group G4 has a positive lens component (biconvex positive lens L41 in FIG. 1) on the most object side, and the positive lens component has an aspherical surface. Thereby, it is possible to satisfactorily correct field curvature and coma in the wide-angle end state.

  In the present embodiment, it is preferable that the first lens group G1, the third lens group G3, and the fourth lens group G4 move in the object direction during zooming from the wide-angle end state to the telephoto end state. Thereby, zooming efficiency can be improved.

  In the present embodiment, the air gap between the third lens group G3 and the fourth lens group G4 in the wide-angle end state is larger than the air gap between the third lens group G3 and the fourth lens group G4 in the telephoto end state. Larger is preferred. As a result, image plane fluctuations due to zooming, particularly waviness at the intermediate position can be reduced.

  FIG. 13 is a schematic cross-sectional view of a digital single-lens reflex camera CAM (optical device) provided with the zoom lens having the above configuration as a photographing lens 1. In the digital single-lens reflex camera CAM shown in FIG. 13, light from an object (subject) (not shown) is collected by the photographing lens 1 and focused on the focusing screen 4 via the quick return mirror 3. The light imaged on the focusing screen 4 is reflected a plurality of times in the pentaprism 5 and guided to the eyepiece lens 6. Thus, the photographer can observe the object (subject) image as an erect image through the eyepiece 6.

  Further, when a release button (not shown) is pressed by the photographer, the quick return mirror 3 is retracted out of the optical path, and light of an object (subject) (not shown) condensed by the photographing lens 1 is captured on the image sensor 7. Form an image. Thereby, the light from the object (subject) is captured by the image sensor 7 and recorded as an object (subject) image in a memory (not shown). In this way, the photographer can photograph an object (subject) with the camera CAM. Note that the camera CAM illustrated in FIG. 13 may hold the photographing lens 1 in a detachable manner, or may be formed integrally with the photographing lens 1. In addition, the zoom lens of the present embodiment can ensure a sufficiently long back focus, and the camera CAM may be a so-called single-lens reflex camera or a compact camera without a quick return mirror or the like.

  Hereinafter, each example according to the present embodiment will be described with reference to the drawings. Tables 1 to 3 are shown below, but these are tables of specifications in the first to third examples. In [Overall specifications], f represents the focal length of the zoom lens, FNO represents the F number, 2ω represents the angle of view, Y represents the image height, TL represents the total lens length, and Bf represents the back focus. In [Lens data], the surface number is the order of the lens surfaces from the object side along the direction in which the light beam travels, r is the radius of curvature of each lens surface, and d is the next optical surface from each optical surface (or The distance between the surfaces, which is the distance on the optical axis to the image plane), nd is the refractive index for the d-line (wavelength 587.6 nm), and νd is the Abbe number for the d-line. When the lens surface is aspherical, an asterisk is attached to the surface number, and the paraxial radius of curvature is indicated in the column of the radius of curvature r. The radius of curvature “0.0000” indicates a plane or an opening. In [variable interval data], Di (where i is an integer) indicates a variable surface interval of the i-th surface. In [Each Group Focal Length Data], the initial surface and focal length of each group are shown. In [Conditional Expression Corresponding Value], values corresponding to the conditional expressions (1) to (3) are shown.

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

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

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

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

(First embodiment)
A first embodiment will be described with reference to FIGS. FIG. 1 is a lens configuration diagram of Example 1, and shows a wide-angle end state (W), an intermediate focal length state (M), and a telephoto end state (T) in order from the top in the drawing. As shown in FIG. 1, the zoom lens according to the first example includes a first lens group G1 having a positive refractive power and a second lens having a negative refractive power, which are arranged in order from the object side along the optical axis. It has a lens group G2, a third lens group G3 having a positive refractive power, and a fourth lens group G4 having a positive refractive power.

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

  The second lens group G2 includes a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a negative meniscus having a concave surface directed toward the object side. And a lens L24. The negative meniscus lens L21 located closest to the object side of the second lens group G2 is an aspheric lens in which an aspheric surface is formed on the glass lens surface on the object side. Note that focusing from a long distance to a short distance is performed by moving the second lens group G2 in the object direction.

  The third lens group G3 includes a thirty-first lens group G31 having a positive refractive power and a thirty-second lens group G32 having a negative refractive power, which are arranged in order from the object side. Camera shake correction (anti-vibration) is performed by moving the lens so as to have a component perpendicular to the axis.

  The thirty-first lens group G31 includes a biconvex positive lens L311, a biconvex positive lens L312, and a cemented lens of a biconvex positive lens L313 and a biconcave negative lens L314 arranged in order from the object side. The thirty-second lens group G32 includes a cemented lens of a positive meniscus lens L321 and a biconcave negative lens L322, which are arranged in order from the object side and have a convex surface directed toward the image surface side. The biconcave negative lens L322 located closest to the image plane in the thirty-second lens group is an aspheric lens having an aspheric lens surface on the image plane side.

  The fourth lens group G4 includes, in order from the object side, a biconvex positive lens L41, a negative lens L42 with a convex surface facing the object side, a biconvex positive lens L43, and a negative meniscus lens L44 with a concave surface facing the object side. And a cemented lens. The biconvex positive lens L41 located closest to the object side in the fourth lens group G4 is an aspheric lens having an aspheric lens surface on the object side.

  In the zoom lens according to the present embodiment having such a configuration, the air gap between the first lens group G1 and the second lens group G2 increases during zooming from the wide-angle end state to the telephoto end state, and the second lens The first lens group G1, the third lens group G3, and the third lens group G3 are arranged so that the air gap between the group G2 and the third lens group G3 is reduced and the air gap between the third lens group G3 and the fourth lens group G4 is reduced. The fourth lens group G4 moves in the object direction. The second lens group G2 once moves in the object direction and then moves in the image direction.

  The aperture stop S is disposed between the second lens group G2 and the third lens group G3, and moves together with the 31st lens group G31 upon zooming from the wide-angle end state to the telephoto end state.

  In the first embodiment, in the lens in which the focal length of the zoom lens is f and the ratio of the image movement amount on the imaging surface to the movement amount of the moving lens group in the blur correction, that is, the image stabilization coefficient is K. In order to correct the rotational shake at the angle θ, the moving lens group for shake correction may be moved by (f · tan θ) / K so as to have a component orthogonal to the optical axis. In the first embodiment at the wide-angle end state, the image stabilization coefficient is 1.034 and the focal length is 28.80 (mm). Therefore, the thirty-second lens group G32 for correcting a rotational blur of 0.59 °. Is moved to 0.286 (mm). Further, in the telephoto end state of the first embodiment, since the image stabilization coefficient is 2.182 and the focal length is 292.0 (mm), the thirty-second lens for correcting the rotation blur of 0.185 °. The movement amount of the group G32 is 0.432 (mm).

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

(Table 1)
[Overall specifications]
Wide-angle end state Intermediate focal length state Telephoto end state f 28.80 to 100.0 to 292.0
FNO 3.6-5.2-5.9
2ω 76.3〜23.6〜8.2
Y 21.6-21.6-21.6
TL 149.809-198.854-230.890
Bf 38.842 〜 76.397 〜 96.070
[Lens data]
Surface number r d nd νd
1 138.3742 2.000 1.85026 32.33
2 69.0999 9.600 1.49782 82.52
3 -614.8204 0.100 1.00000
4 64.5435 6.700 1.59319 67.87
5 381.8433 D5 1.00000
* 6 142.3349 1.000 1.83481 42.72
7 19.4996 6.700 1.00000
8 -38.6991 1.000 1.77250 49.61
9 89.2613 0.100 1.00000
10 41.7553 4.800 1.84666 23.77
11 -36.9161 1.072 1.00000
12 -25.5852 1.000 1.80400 46.58
13 -739.0998 D13 1.00000
14 0.0000 0.500 1.00000 (Aperture)
15 45.2694 3.300 1.81600 46.63
16 -253.2898 0.100 1.00000
17 46.0894 3.200 1.60300 65.47
18 -580.8365 0.100 1.00000
19 32.4152 4.900 1.49782 82.56
20 -45.0434 1.000 1.84666 23.77
21 68.2762 3.459 1.00000
22 -104.9462 2.950 1.78472 25.68
23 -28.646 1.000 1.74443 49.53
* 24 55.4025 D24 1.00000
* 25 39.5596 4.400 1.58913 61.18
26 -37.0692 0.100 1.00000
27 83.4772 1.500 1.78472 25.68
28 36.3950 2.100 1.00000
29 89.6754 7.600 1.58144 40.75
30 -14.3412 1.500 1.81600 46.62
31 -120.8659 Bf 1.00000
[Aspherical data]
6th surface κ = -5.9513, A4 = 3.17E-06, A6 = -8.30E-09, A8 = 6.26E-11, A10 = -1.47E-13, A12 = 2.80E-16
24th surface κ = 1.1502, A4 = -3.23E-06, A6 = -8.48E-09, A8 = 2.09E-11, A10 = 0.00E + 00, A12 = 0.00E + 00
25th surface κ = 1.2459, A4 = -1.16E-05, A6 = 7.74E-09, A8 = 5.74E-11, A10 = 0.00E + 00, A12 = 0.00E + 00
[Variable interval data]
Wide-angle end state Intermediate focal length state Telephoto end state
D5 2.619 34.441 59.314
D13 28.913 12.892 1.472
D24 7.653 3.342 2.252
[Each group focal length data]
Group number Group first surface Group focal length G1 1 105.481
G2 6 -17.400
G3 15 43.286
G4 25 57.002
[Conditional expression values]
Conditional expression (1) X1 / fw = 2.82
Conditional expression (2) (-f2) /Bfw=0.45
Conditional expression (3) f1 / f3 = 2.44

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

  FIGS. 2A and 2B are diagrams illustrating various aberrations at the time of focusing on infinity in the wide-angle end state of the zoom lens according to the first example and blur correction for 0.59 ° rotational shake. It is a meridional transverse aberration diagram at the time. FIG. 3 is a diagram illustrating various aberrations when the zoom lens according to Example 1 is focused at infinity in the intermediate focal length state. 4A and 4B are diagrams illustrating various aberrations at the time of focusing on infinity in the telephoto end state of the zoom lens according to the first example and blur correction for 0.185 ° rotational blur. It is a meridional transverse aberration diagram at the time.

  In each aberration diagram, FNO represents an F number, and Y represents an image height (unit: mm). The spherical aberration diagram shows the F-number value corresponding to the maximum aperture, the astigmatism diagram and the distortion diagram show the maximum image height, and the coma diagram shows the value of each image height. Further, d indicates various aberrations with respect to the d-line (wavelength 587.6 nm), g indicates various aberrations with respect to the g-line (wavelength 435.8 nm), and those not described indicate various aberrations with respect to the d-line. In the astigmatism diagram, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane. The explanation of the above aberration diagrams is the same in the other examples, and the explanation is omitted.

  As is apparent from each aberration diagram, the first embodiment has a zoom ratio of about 10 times, an angle of view of 70 ° or more in the wide-angle end state, and each of the wide-angle end state to the telephoto end state. It can be seen that, in the focal length state, various aberrations are corrected well and the imaging performance is excellent.

(Second embodiment)
A second embodiment will be described with reference to FIGS. FIG. 5 is a lens configuration diagram of Example 2, and shows a wide-angle end state (W), an intermediate focal length state (M), and a telephoto end state (T) in order from the top in the drawing. As shown in FIG. 5, the zoom lens according to the second example includes a first lens group G1 having a positive refractive power and a second lens having a negative refractive power, which are arranged in order from the object side along the optical axis. It has a lens group G2, a third lens group G3 having a positive refractive power, and a fourth lens group G4 having a positive refractive power.

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

  The second lens group G2 includes a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a negative meniscus having a concave surface directed toward the object side. And a lens L24. The negative meniscus lens L21 located closest to the object side in the second lens group G2 is an aspheric lens in which an aspheric surface is formed by providing a resin layer on the glass lens surface on the object side. Note that focusing from a long distance to a short distance is performed by moving the second lens group G2 in the object direction.

  The third lens group G3 includes a thirty-first lens group G31 having a positive refractive power and a thirty-second lens group G32 having a negative refractive power, which are arranged in order from the object side. Camera shake correction (anti-vibration) is performed by moving the lens so as to have a component perpendicular to the axis.

  The thirty-first lens group G31 includes a biconvex positive lens L311, a positive meniscus lens L312 having a convex surface facing the object side, a biconvex positive lens L313, and a biconcave negative lens L314 arranged in order from the object side. And a lens. The thirty-second lens group G32 includes a cemented lens of a positive meniscus lens L321 and a biconcave negative lens L322, which are arranged in order from the object side and have a convex surface directed toward the image surface side. Note that the positive meniscus lens L321 located on the most object side of the thirty-second lens group G32 and having a convex surface facing the image surface side is an aspherical lens having an aspherical shape by providing a resin layer on the lens surface on the object side. is there.

  The fourth lens group G4 includes, in order from the object side, a biconvex positive lens L41, a negative lens L42 with a convex surface facing the object side, a biconvex positive lens L43, and a negative meniscus lens L44 with a concave surface facing the object side. And a cemented lens. The biconvex positive lens L41 located closest to the object side in the fourth lens group G4 is an aspheric lens having an aspheric lens surface on the object side.

  In the zoom lens according to the present embodiment having such a configuration, the air gap between the first lens group G1 and the second lens group G2 increases during zooming from the wide-angle end state to the telephoto end state, and the second lens The first lens group G1, the third lens group G3, and the third lens group G3 are arranged so that the air gap between the group G2 and the third lens group G3 is reduced and the air gap between the third lens group G3 and the fourth lens group G4 is reduced. The fourth lens group G4 moves in the object direction. The second lens group G2 once moves in the object direction and then moves in the image direction.

  The aperture stop S is disposed between the second lens group G2 and the third lens group G3, and moves together with the 31st lens group G31 upon zooming from the wide-angle end state to the telephoto end state.

  In the second embodiment, in the lens in which the focal length of the zoom lens is f and the ratio of the image movement amount on the imaging surface to the movement amount of the moving lens group in blur correction, that is, the image stabilization coefficient is K. In order to correct the rotational shake at the angle θ, the moving lens group for shake correction may be moved by (f · tan θ) / K so as to have a component orthogonal to the optical axis. In the wide-angle end state of the second example, since the image stabilization coefficient is 1.079 and the focal length is 28.80 (mm), the thirty-second lens group G32 for correcting a rotational blur of 0.59 °. Is moved to 0.274 (mm). Further, in the telephoto end state of the second embodiment, since the image stabilization coefficient is 2.203 and the focal length is 292.0 (mm), the thirty-second lens for correcting the rotation blur of 0.185 °. The movement amount of the group G32 is 0.428 (mm).

  Table 2 below shows values of various specifications of the zoom lens according to the second example. In addition, the surface numbers 1-33 in Table 2 respond | correspond to the surfaces 1-33 shown in FIG.

(Table 2)
[Overall specifications]
Wide-angle end state Intermediate focal length state Telephoto end state f 28.80 to 100.0 to 292.0
FNO 3.6-5.2-5.8
2ω 76.2 to 23.6 to 8.2
Y 21.6-21.6-21.6
TL 151.130-202.200-231.329
Bf 38.131 to 80.180 to 93.120
[Lens data]
Surface number r d nd νd
1 145.2597 2.000 1.85026 32.33
2 69.988 9.687 1.49782 82.52
3 -554.5008 0.100 1.00000
4 68.1218 6.975 1.60300 65.44
5 518.3016 D5 1.00000
* 6 239.3638 0.100 1.55389 38.09
7 239.3638 1.000 1.81600 46.63
8 19.9078 6.569 1.00000
9 -40.5746 1.000 1.81600 46.63
10 95.5484 0.100 1.00000
11 45.3125 4.900 1.84666 23.77
12 -38.3032 1.235 1.00000
13 -25.2325 1.000 1.81600 46.63
14 -142.2965 D14 1.00000
15 0.0000 0.500 1.00000 (Aperture)
16 37.0918 3.879 1.60300 65.47
17 -143.2937 0.100 1.00000
18 42.6758 3.171 1.75500 52.29
19 201.4015 0.100 1.00000
20 33.71 6.946 1.49782 82.56
21 -44.318 1.000 1.84666 23.77
22 75.3195 2.992 1.00000
* 23 -116.173 0.050 1.55389 38.09
24 -116.173 3.107 1.78472 25.67
25 -26.2336 1.000 1.81600 46.63
26 64.2579 D26 1.00000
* 27 39.5885 4.080 1.60300 65.47
28 -37.8831 0.100 1.00000
29 97.9595 1.000 1.85026 32.35
30 43.282 2.436 1.00000
31 271.8765 6.570 1.57501 41.49
32 -14.2413 1.000 1.81600 46.63
33 -85.1726 Bf 1.00000
[Aspherical data]
6th surface κ = 1.0000, A4 = 5.43E-06, A6 = -9.71E-09, A8 = 7.57E-11, A10 = -2.45E-13, A12 = 5.38E-16
23rd surface κ = 1.0000, A4 = 4.75E-06, A6 = 5.25E-09, A8 = 1.28E-11, A10 = 0.00E + 00, A12 = 0.00E + 00
27th surface κ = 1.0000, A4 = -1.59E-05, A6 = 1.45E-08, A8 = 3.20E-11, A10 = 0.00E + 00, A12 = 0.00E + 00
[Variable interval data]
Wide-angle end state Intermediate focal length state Telephoto end state
D5 2.49389 32.29109 60.72713
D14 30.74270 13.70992 1.95143
D26 7.06627 3.32296 2.83454
[Each group focal length data]
Group number Group first surface Group focal length G1 1 106.543
G2 6 -17.800
G3 16 41.283
G4 27 60.839
[Conditional expression values]
Conditional expression (1) X1 / fw = 2.78
Conditional expression (2) (-f2) /Bfw=0.47
Conditional expression (2) f1 / f3 = 2.58

  From the table of specifications shown in Table 2, it can be seen that the zoom lens according to Example 2 satisfies all the conditional expressions (1) to (3).

  6A and 6B are diagrams illustrating various aberrations at the time of focusing at infinity in the wide-angle end state of the zoom lens according to Example 2 and blur correction with respect to a rotational blur of 0.59 °. It is a meridional transverse aberration diagram at the time. FIG. 7 is a diagram illustrating various aberrations when the zoom lens according to Example 2 is focused at infinity in the intermediate focal length state. FIGS. 8A and 8B are diagrams illustrating various aberrations at the time of focusing at infinity in the telephoto end state of the zoom lens according to Example 2 and blur correction for 0.185 ° rotational shake. It is a meridional transverse aberration diagram at the time.

  As is apparent from each aberration diagram, the second embodiment has a zoom ratio of about 10 times, has an angle of view of 70 ° or more in the wide-angle end state, and has various angles from the wide-angle end state to the telephoto end state. It can be seen that, in the focal length state, various aberrations are corrected well and the imaging performance is excellent.

(Third embodiment)
A third embodiment will be described with reference to FIGS. 9 to 12 and Table 3. FIG. FIG. 9 is a lens configuration diagram of the third example, and shows a wide-angle end state (W), an intermediate focal length state (M), and a telephoto end state (T) in order from the top in the drawing. As shown in FIG. 9, the zoom lens according to the third example includes a first lens group G1 having a positive refractive power arranged in order from the object side along the optical axis, and a second lens having a negative refractive power. It has a lens group G2, a third lens group G3 having a positive refractive power, and a fourth lens group G4 having a positive refractive power.

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

  The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a biconcave negative lens L24. The negative meniscus lens L21 located closest to the object side in the second lens group G2 is an aspheric lens in which an aspheric surface is formed by providing a resin layer on the glass lens surface on the object side. Note that focusing from a long distance to a short distance is performed by moving the second lens group G2 in the object direction.

  The third lens group G3 includes a thirty-first lens group G31 having a positive refractive power and a thirty-second lens group G32 having a negative refractive power, which are arranged in order from the object side. Camera shake correction (anti-vibration) is performed by moving the lens so as to have a component perpendicular to the axis.

  The thirty-first lens group G31 has a biconvex positive lens L311 arranged in order from the object side, a positive meniscus lens L312 having a convex surface on the object side, and a convex surface on the biconvex positive lens L313 and the image surface side. And a cemented lens with the negative meniscus lens L314. The thirty-second lens group G32 includes a cemented lens of a positive meniscus lens L321 and a biconcave negative lens L322, which are arranged in order from the object side and have a convex surface directed toward the image surface side. Note that the positive meniscus lens L321 located on the most object side of the thirty-second lens group G32 and having a convex surface facing the image surface side is an aspherical lens having an aspherical shape by providing a resin layer on the lens surface on the object side. is there.

  The fourth lens group G4 includes a biconvex positive lens L41, a cemented lens of a biconvex positive lens L42 and a biconcave negative lens L43, and a positive meniscus lens L44 having a convex surface directed toward the image plane, arranged in order from the object side. And a cemented lens with a negative meniscus lens L45 having a concave surface facing the object side. The biconvex positive lens L41 located closest to the object side in the fourth lens group G4 is an aspheric lens having an aspheric lens surface on the object side.

  In the zoom lens according to the present embodiment having such a configuration, the air gap between the first lens group G1 and the second lens group G2 increases during zooming from the wide-angle end state to the telephoto end state, and the second lens The first lens group G1, the third lens group G3, and the third lens group G3 are arranged so that the air gap between the group G2 and the third lens group G3 is reduced and the air gap between the third lens group G3 and the fourth lens group G4 is reduced. The fourth lens group G4 moves in the object direction. The second lens group G2 once moves in the object direction and then moves in the image direction.

  The aperture stop S is disposed between the second lens group G2 and the third lens group G3, and moves together with the 31st lens group G31 upon zooming from the wide-angle end state to the telephoto end state.

  In the third embodiment, in the lens in which the focal length of the zoom lens is f and the ratio of the image movement amount on the imaging surface to the movement amount of the moving lens group in the blur correction, that is, the image stabilization coefficient is K. In order to correct the rotational shake at the angle θ, the moving lens group for shake correction may be moved by (f · tan θ) / K so as to have a component orthogonal to the optical axis. In the third embodiment, in the wide-angle end state, the image stabilization coefficient is 1.114, and the focal length is 28.80 (mm). Therefore, the thirty-second lens group G32 for correcting a rotational shake of 0.589 °. The amount of movement is 0.266 (mm). Further, in the telephoto end state of the second embodiment, the image stabilization coefficient is 2.202, and the focal length is 292.0 (mm). Therefore, the 32nd lens for correcting the rotation blur of 0.185 °. The movement amount of the group G32 is 0.428 (mm).

  Table 3 below shows values of various specifications of the zoom lens according to the third example. The surface numbers 1 to 34 in Table 3 correspond to the surfaces 1 to 34 shown in FIG.

(Table 3)
[Overall specifications]
Wide-angle end state Intermediate focal length state Telephoto end state f 28.80 to 100.0 to 292.0
FNO 3.5 to 5.1 to 5.8
2ω 76.3〜23.6〜8.2
Y 21.6-21.6-21.6
TL 153.341-203.413-233.297
Bf 40.517-83.577-96.750
[Lens data]
Surface number r d nd νd
1 148.2837 2.000 1.85026 32.34
2 71.0135 9.050 1.49782 82.52
3 -553.8532 0.100 1.00000
4 68.4004 6.892 1.60300 65.44
5 508.9996 D5 1.00000
* 6 156.5097 0.050 1.55389 38.09
7 156.5097 1.000 1.81600 46.63
8 19.5154 6.800 1.00000
9 -35.2222 1.000 1.75500 52.29
10 95.0325 0.299 1.00000
11 45.9155 4.600 2.00069 25.46
12 -46.5336 1.041 1.00000
13 -28.3453 1.000 1.81600 46.63
14 2140.1539 D14 1.00000
15 0.0000 0.500 1.00000
16 36.8857 4.000 1.60300 65.47
17 -84.6736 0.100 1.00000
18 48.7765 3.200 1.60300 65.47
19 104.8413 0.100 1.00000
20 39.7568 4.600 1.49782 82.56
21 -32.6962 1.000 1.84666 23.78
22 -392.7967 1.980 1.00000
* 23 -71.5102 0.100 1.55389 38.09
24 -71.5102 3.532 1.78472 25.68
25 -22.1662 1.000 1.81600 46.63
26 122.3173 D26 1.00000
* 27 75.0258 4.586 1.60300 65.47
28 -28.6154 0.100 1.00000
29 44.1044 4.800 1.57501 41.49
30 -45.0909 1.000 1.81600 46.63
31 31.4567 2.600 1.00000
32 -87.0457 3.200 1.57501 41.49
33 -25.2164 2.000 1.75520 27.51
34 -58.7157 Bf 1.00000
[Aspherical data]
6th surface κ = 1.0000, A4 = 4.07E-06, A6 = -1.04E-08, A8 = 5.95E-11, A10 = 2.77E-14, A12 = -1.47E-16
23rd surface κ = 1.0000, A4 = 5.78E-06, A6 = -5.31E-09, A8 = 4.81E-11, A10 = 0.00E + 00, A12 = 0.00E + 00
27th surface κ = 1.0000, A4 = -2.25E-05, A6 = 6.24E-09, A8 = -3.49E-11, A10 = 0.00E + 00, A12 = 0.00E + 00
[Variable interval data]
Wide-angle end state Intermediate focal length state Telephoto end state
D5 2.77841 32.53174 61.42865
D14 30.00109 12.73346 1.13320
D26 7.81501 2.34109 1.75638
[Each group focal length data]
Group number Group first surface Group focal length G1 1 107.652
G2 6 -17.800
G3 16 44.990
G4 27 69.305
[Conditional expression values]
Conditional expression (1) X1 / fw = 2.78
Conditional expression (2) (-f2) /Bfw=0.44
Conditional expression (2) f1 / f3 = 2.39

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

  FIGS. 10A and 10B are diagrams illustrating various aberrations at the time of focusing at infinity in the wide-angle end state of the zoom lens according to Example 3 and blur correction for 0.589 ° rotational shake. It is a meridional transverse aberration diagram at the time. FIG. 11 is a diagram illustrating various aberrations when the zoom lens according to Example 3 is focused at infinity in the intermediate focal length state. FIGS. 12A and 12B are graphs showing various aberrations at the time of focusing on infinity in the telephoto end state of the zoom lens according to the third example and blur correction for 0.185 ° rotational shake. It is a meridional transverse aberration diagram at the time.

  As is apparent from each aberration diagram, the third embodiment has a zoom ratio of about 10 times, an angle of view of 70 ° or more in the wide-angle end state, and each of the wide-angle end state to the telephoto end state. It can be seen that, in the focal length state, various aberrations are corrected well and the imaging performance is excellent.

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

  In the above embodiment, a zoom lens having a four-group configuration is shown, but the present invention can also be applied to other group configurations such as a fifth group and a sixth group. Specifically, a configuration in which a positive or negative lens group is added on the most object side, a configuration in which a positive or negative lens group is added on the most image side, or a positive or negative value between the third group and the fourth group. The structure which added the lens group is mentioned.

  In addition, a single lens group, a plurality of lens groups, or a partial lens group may be moved in the optical axis direction to be a focusing lens group that performs focusing from an object at infinity to a near object. The focusing lens group can be applied to autofocus, and is also suitable for driving a motor for autofocus (such as an ultrasonic motor). In particular, the second lens group G2 is preferably a focusing lens group.

  Alternatively, the lens group or the partial lens group may be vibrated in a direction perpendicular to the optical axis, and may be an anti-vibration lens group for correcting image blur caused by camera shake. In particular, as described above, it is preferable that the thirty-second lens group G32 is an anti-vibration lens group.

  Further, the lens surface may be formed as a spherical surface, a flat surface, or an aspherical surface. It is preferable that the lens surface is a spherical surface or a flat surface because lens processing and assembly adjustment are facilitated, and deterioration of optical performance due to errors in processing and assembly adjustment can be prevented. Further, even when the image plane is deviated, it is preferable because there is little deterioration in drawing performance. On the other hand, when the lens surface is an aspheric surface, the aspheric surface is an aspheric surface by grinding, a glass mold aspheric surface made of glass with an aspheric shape, or a composite type non-spherical surface made of resin on the glass surface. Any aspherical surface may be used. The lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

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

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

  In the zoom lens according to the present embodiment, the zoom ratio is 5 to 18 times, more preferably 8 to 12 times.

  In the zoom lens according to the present embodiment, it is preferable that the first lens group G1 has two positive lenses and one negative lens. Further, in the first lens group G1, it is preferable to dispose the lenses in order of negative positive / positive in order from the object side.

  In the zoom lens according to the present embodiment, it is preferable that the second lens group G2 has one positive lens and three negative lenses. In the second lens group G2, it is preferable to dispose lens components in order of negative, negative, positive and negative in order from the object side.

  In the zoom lens according to the present embodiment, it is preferable that the third lens group G3 includes three positive lenses and two negative lenses. In addition, it is preferable that the third lens group G3 includes, in order from the object side, two positive lens components that are fixed during vibration isolation and one negative lens component that is movable during vibration isolation.

  In the zoom lens according to the present embodiment, it is preferable that the fourth lens group G4 has two positive lenses and one negative lens.

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

1 is a configuration diagram of a zoom lens according to a first example. FIG. (A) and (b) are diagrams showing various aberrations at the time of focusing on infinity in the wide-angle end state of the zoom lens according to the first example and when shake correction is performed for 0.59 ° rotational blur. It is a meridional lateral aberration diagram. FIG. 5 is a diagram illustrating various aberrations when the zoom lens according to Example 1 is in focus at infinity in the intermediate focal length state. (A) and (b) are diagrams showing various aberrations at the time of focusing on infinity in the telephoto end state of the zoom lens according to the first example and when shake correction is performed for a rotational shake of 0.185 °. It is a meridional lateral aberration diagram. It is a block diagram of the zoom lens which concerns on 2nd Example. (A) and (b) are diagrams showing various aberrations at the time of focusing on infinity in the wide-angle end state of the zoom lens according to the second example and when blur correction is performed for 0.59 ° rotational blur. It is a meridional lateral aberration diagram. FIG. 12 is a diagram illustrating various aberrations when the zoom lens according to Example 2 is focused at infinity in the intermediate focal length state. (A) and (b) are diagrams showing various aberrations at the time of focusing at infinity in the telephoto end state of the zoom lens according to the second example and when shake correction is performed for rotational shake of 0.185 °. It is a meridional lateral aberration diagram. FIG. 6 is a configuration diagram of a zoom lens according to a third example. FIGS. 9A and 9B are graphs showing various aberrations at the time of focusing on infinity in the wide-angle end state of the zoom lens according to Example 3, and when shake correction is performed for a rotational shake of 0.589 °. It is a meridional lateral aberration diagram. FIG. 11 is a diagram illustrating various aberrations when the zoom lens according to Example 3 is in focus at infinity in the intermediate focal length state. (A) and (b) are diagrams showing various aberrations at the time of focusing on infinity in the telephoto end state of the zoom lens according to the third example and when shake correction is performed for a rotational shake of 0.185 °. It is a meridional lateral aberration diagram. It is a schematic sectional drawing of the digital single-lens reflex camera which has the zoom lens of the said structure.

Explanation of symbols

G1 1st lens group G2 2nd lens group G3 3rd lens group G31 31st lens group (positive lens group)
G32 32nd lens group (negative lens group)
G4 4th lens group S Aperture I Image surface CAM Single-lens reflex camera (optical equipment)

Claims (10)

A first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a first lens group having a positive refractive power, arranged in order from the object side. It consists of 4 lens groups by 4 lens groups,
When zooming from the wide-angle end state to the telephoto end state, the distance between the lens groups changes,
The third lens group includes a positive lens group having a positive refractive power and a negative lens group having a negative refractive power, arranged in order from the object side,
Moving the negative lens group to have a component orthogonal to the optical axis;
The negative lens group includes a cemented lens of a biconcave negative lens and a positive lens,
The amount of movement of the first lens group during zooming from the wide-angle end state to the telephoto end state is X1, the focal length of the entire lens system in the wide-angle end state is fw, and the focal length of the second lens group is f2. When the back focus in the wide-angle end state is Bfw, the following formula 2.6 <X1 / fw <4.2
0.430 <(− f2) / Bfw <0.540
A zoom lens that satisfies the following conditions. A first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a first lens group having a positive refractive power, arranged in order from the object side. It consists of 4 lens groups by 4 lens groups,
When zooming from the wide-angle end state to the telephoto end state, the distance between the lens groups changes,
The third lens group includes a positive lens group having a positive refractive power and a negative lens group having a negative refractive power, arranged in order from the object side,
Moving the negative lens group to have a component orthogonal to the optical axis;
The negative lens group includes a cemented lens of a biconcave negative lens and a positive lens,
The amount of movement of the first lens group during zooming from the wide-angle end state to the telephoto end state is X1, the focal length of the entire lens system in the wide-angle end state is fw, and the focal length of the first lens group is f1. When the focal length of the third lens group is f3, the following expression 2.6 <X1 / fw <4.2
2.20 <f1 / f3 ≦ 2.44
A zoom lens that satisfies the following conditions. The negative lens group, a zoom lens according to claim 1 or 2, characterized in that it has at least one aspherical. The fourth lens group has a positive lens component closest to the object side,
The positive lens component, a zoom lens according to any one of claims 1 to 3, characterized in that it has an aspherical surface. Angle end state to the telephoto end state, the first lens group, any one of claims 1-4, wherein the third lens group and the fourth lens group and said moving toward the object The zoom lens according to item. Upon zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group decreases, the zoom lens according to any one of claims 1 to 5, characterized in that the distance between the second lens group and the third lens group is changed. The air gap between the third lens group and the fourth lens group in the wide-angle end state is larger than the air gap between the third lens group and the fourth lens group in the telephoto end state. The zoom lens according to any one of 1 to 6 . An optical apparatus characterized by having a zoom lens according to any one of claims 1-7. A first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a first lens group having a positive refractive power, arranged in order from the object side. An anti-vibration method for a zoom lens comprising substantially four lens groups by four lens groups,
When zooming from the wide-angle end state to the telephoto end state, the distance between the lens groups changes,
The third lens group includes a positive lens group having a positive refractive power and a negative lens group having a negative refractive power, arranged in order from the object side,
Moving the negative lens group to have a component orthogonal to the optical axis;
The negative lens group includes a cemented lens of a biconcave negative lens and a positive lens,
The amount of movement of the first lens group during zooming from the wide-angle end state to the telephoto end state is X1, the focal length of the entire lens system in the wide-angle end state is fw, and the focal length of the second lens group is f2. When the back focus in the wide-angle end state is Bfw, the following formula 2.6 <X1 / fw <4.2
0.430 <(− f2) / Bfw <0.540
An anti-vibration method for a zoom lens characterized by satisfying the following conditions: A first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a first lens group having a positive refractive power, arranged in order from the object side. An anti-vibration method for a zoom lens comprising substantially four lens groups by four lens groups,
When zooming from the wide-angle end state to the telephoto end state, the distance between the lens groups changes,
The third lens group includes a positive lens group having a positive refractive power and a negative lens group having a negative refractive power, arranged in order from the object side,
Moving the negative lens group to have a component orthogonal to the optical axis;
The negative lens group includes a cemented lens of a biconcave negative lens and a positive lens,
The amount of movement of the first lens group during zooming from the wide-angle end state to the telephoto end state is X1, the focal length of the entire lens system in the wide-angle end state is fw, and the focal length of the first lens group is f1. When the focal length of the third lens group is f3, the following expression 2.6 <X1 / fw <4.2
2.20 <f1 / f3 ≦ 2.44
An anti-vibration method for a zoom lens characterized by satisfying the following conditions:

Images