JP2007233147A - Zoom lens with image blur correcting function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a zoom lens with an image blur correcting function whose aberrations are satisfactorily corrected and by which a stable photographic image is obtained in spite of compacter constitution. <P>SOLUTION: The zoom lens with the image blur correcting function includes a first positive lens group G1, a second negative lens group G2, a third positive lens group G3 having a positive G31 group, a positive G32 group and G33 group, and a fourth positive lens group G4 in order from an object side. Power is varied by the movement of the second lens group G2, and focusing and the correction of the fluctuation of an image surface caused by the power varying operation are performed by the movement of the fourth lens group G4. Image blur is corrected by moving the entire G32 group in a perpendicular direction to an optical axis Z1. Since the G31 group and the G32 group have positive refractive power, the diameters of luminous fluxes made incident on the G32 group and the G33 group respectively are reduced, whereby the diameters of lenses constituting the G31 group and the G32 group become small. Therefore, the entire constitution of the third lens group G3 is made compact. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is an image blur suitable for mounting on a small-sized imaging apparatus such as a digital camera or a consumer video camera using an imaging element such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). The present invention relates to a zoom lens with a correction function.

  In recent years, with the spread of personal computers to ordinary homes and the like, digital still cameras (hereinafter simply referred to as digital cameras) capable of inputting image information such as photographed landscapes and human images to personal computers have rapidly spread. It's getting on.

  In these image pickup apparatuses, an image pickup element such as a CCD or a CMOS is used. With the recent increase in the number of pixels in an image pickup device, it has been demanded that an optical system mounted on an image pickup apparatus be compatible with high resolution and high performance. At the same time, downsizing of the image sensor is also progressing, and there is a strong demand for downsizing of the entire apparatus. From such a background, there has been proposed a bending imaging lens in which a reflecting member is provided in the middle of the optical system and the optical axis is bent to reduce the thickness in the depth direction of the lens (see, for example, Patent Document 1). ).

In addition, when an attempt is made to take an image from a moving object such as a moving car using the above-described image pickup apparatus, vibrations are often transmitted to the image taking system and the taken image is blurred. In particular, recent downsized and light-weight imaging devices tend to cause image blur due to camera shake, which is an obstacle to obtaining a good captured image. For this reason, various anti-vibration optical systems having a function of preventing blurring of a photographed image accompanying vibration of the photographing optical system have been proposed. For example, in Patent Document 2, a refractive variable apex angle prism is arranged on the most object side, and an image is deflected by changing the apex angle of the prism in response to the vibration of the photographing system, thereby stabilizing the image. Yes. The zoom optical system disclosed in Patent Document 3 includes, in order from the object side, a positive first lens group that is fixed during zooming and focusing, and a negative second lens group that has a zoom function. And a positive third lens group, and a positive fourth lens group having both a correction function for correcting an image plane fluctuating due to a zooming operation and a focusing function, and the third lens group is negative The thirty-first lens group and the positive thirty-second lens group are moved, and by moving the thirty-second lens group in the direction perpendicular to the optical axis, blurring of the photographed image when the variable magnification optical system vibrates is corrected. ing. Further, in Patent Document 4, in order from the object side, a positive first lens group fixed at the time of zooming and focusing, a positive second lens group having a zooming function, and a positive third lens group, And a positive fourth lens group having a function of correcting image plane variation due to zooming and a focusing function, and the third lens group includes a positive third lens group, a negative third lens group, and a single lens. A third c lens group is provided, and by moving the third b lens group in a direction perpendicular to the optical axis, blurring of the photographed image when the variable magnification optical system vibrates is corrected.
JP 2003-202500 A JP-A-61-223819 JP 11-237550 A JP 2005-148437 A

  However, Patent Document 2 has a problem in that the amount of eccentric chromatic aberration of chromatic aberration is increased at the time of image stabilization, particularly on the telephoto side, since the image stabilization is performed using a refractive variable apex angle prism. Further, in Patent Document 3, since a lens having a negative refractive power is preceded in the third lens group, the diameter of the light beam incident on the 32nd lens group to be moved when performing vibration isolation is expanded. . For this reason, there is a problem that the lens outer diameter of the thirty-second lens group is increased, the configuration of the entire lens system is increased, and the load on the lens driving system is increased. Furthermore, the variable magnification optical system disclosed in Patent Document 4 is insufficient in terms of compactness.

  SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and an object thereof is a zoom lens with an image blur correction function capable of obtaining a stable photographed image with various aberrations corrected well while having a more compact configuration. Is to provide.

  The zoom lens with an image blur correction function of the present invention includes 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 positive lens power. A fourth lens group having refractive power is provided in order from the object side. Here, the zooming operation is performed by moving the second lens group on the optical axis, and the correction and focusing of the image plane variation due to the zooming operation are performed by moving the fourth lens group on the optical axis. It is like that. The third lens group includes a first sub lens group (G31 group) having a positive refractive power, a second sub lens group (G32 group) having a positive refractive power, and a third sub lens having a positive or negative refractive power. The lens group (G33 group) is arranged in order from the object side, and image blur caused by vibration is corrected by moving the entire second sub lens group in a direction perpendicular to the optical axis. ing.

  In the zoom lens with an image blur correction function of the present invention, since the refractive powers of the first sub lens group and the second sub lens group in the third lens group are positive, the second sub lens group and the third sub lens group The diameter of each incident light beam is reduced. For this reason, the diameters of the lenses constituting each of the first sub lens group and the second sub lens group can be reduced. Therefore, the overall configuration of the third lens group is made compact while ensuring a good image blur correction function.

  In the zoom lens with an image blur correction function of the present invention, a reflective surface for constituting a bending optical system may be provided in the first lens group. In this case, the first lens group is configured to include at least one negative lens, a reflecting member having a reflecting surface, and at least one positive lens in order from the object side, for example.

The zoom lens with an image blur correction function according to the present invention is preferably configured to satisfy both the following conditional expressions (1) and (2).
3.0 <f3 / fw <5.0 (1)
1.2 <f32 / f3 <2.0 (2)
Here, f3 is the focal length of the third lens group, fw is the focal length of the entire system at the wide angle end, and f32 is the focal length of the second sub lens group.

  In the zoom lens with an image blur correction function of the present invention, each of the first sub lens group and the second sub lens group may be constituted by a single lens. In that case, the single lens of the first sub-lens group has an aspherical shape that weakens the positive refractive power as the object side surface moves away from the optical axis toward the peripheral portion, and the image side surface is light. The single lens of the second sub-lens group is configured so that its surface on the object side is away from the optical axis and has a peripheral edge. It is desirable to have an aspherical shape that increases the positive refractive power toward the portion.

  In the zoom lens with an image blur correction function according to the present invention, it is preferable that the third sub lens group includes a cemented lens including a positive lens and a negative lens. This is particularly advantageous for reducing chromatic aberration.

  According to the zoom lens with an image blur correction function of the present invention, the positive first lens group, the negative second lens group, the positive third lens group, and the positive fourth lens group are sequentially provided from the object side, A zooming operation is performed by moving the two lens groups on the optical axis, and an image plane variation is corrected and focused by the zooming operation by moving the fourth lens group on the optical axis. A third lens group is formed by sequentially arranging one sub lens group, a positive second sub lens group, and a positive or negative third sub lens group from the object side, and the entire second sub lens group is formed when vibration occurs. Since it is moved in the direction perpendicular to the optical axis, the third lens group can be reduced in size and weight while exhibiting a good image blur correction function. Therefore, it is possible to achieve a compact overall configuration while ensuring high imaging performance.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a first configuration example of a zoom lens with an image blur correction function (hereinafter simply referred to as a zoom lens) as an embodiment of the present invention. This configuration example corresponds to a lens configuration of a first numerical example (Example 1: FIGS. 3 to 5) described later. FIG. 2 shows a second configuration example of the zoom lens according to the present embodiment. The second configuration example corresponds to the lens configuration of a second numerical example (Example 2: FIGS. 6 to 8) described later. In particular, FIGS. 1A and 2A show lens arrangements when focusing on infinity at the wide-angle end, and FIGS. 1B and 2B show lenses when focusing on infinity at the telephoto end. The arrangement is shown. In FIG. 1B and FIG. 2B, the reference sign Si is set so that the surface of the component on the most object side is the first, and increases sequentially toward the image side (imaging side). The attached i-th surface is shown. The symbol Ri indicates the radius of curvature of the surface Si. A symbol Di indicates a surface interval on the optical axis Z1 between the i-th surface Si and the i + 1-th surface Si + 1. Since the basic configuration is the same for each configuration example, the configuration example of the zoom lens shown in FIG. 1 will be basically described below, and the configuration example of FIG. 2 will also be described as necessary.

  This zoom lens is mounted and used in, for example, a compact camera, a digital still camera, a consumer video camera, and the like. In this zoom lens, in order from the object side along the optical axis Z1, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a first lens group having a positive refractive power. 3 lens group G3 and 4th lens group G4 which has positive refractive power are provided. An aperture stop St is disposed inside the third lens group G3. An imaging surface of an image sensor such as a CCD (Charge Coupled Device) (not shown) is disposed on the image plane Simg of the zoom lens. Various filters GC such as an infrared cut filter may be disposed between the fourth lens group G4 and the imaging plane Simg.

  In this zoom lens, the zooming operation is performed by moving the second lens group G2 on the optical axis Z1. For example, when zooming from the wide-angle side to the telephoto side, the second lens group G2 is moved from the object side to the image side. The movement locus of the second lens group G2 is substantially linear as shown in FIG. When the second lens group G2 is moved, the fourth lens group G4 is also moved on the optical axis Z1 to correct the image plane variation due to the zooming operation. By this movement of the fourth lens G4, focusing is also performed. The fourth lens group G4 moves so as to draw a curved locus represented by a solid line in FIG. On the other hand, the first lens group G1 and the third lens group G3 are fixed groups that do not move during zooming and focusing.

  The first lens group G1 is composed of four lenses L11 to L14. The lens L11 is, for example, a negative meniscus lens having a convex surface facing the object side. The lens L12 is an optical path conversion element having a flat entrance surface and exit surface. The lens L13 is a plano-convex lens having a convex surface facing the image side, for example. The lens L14 has, for example, a biconvex shape. Both surfaces S7 and S8 of the lens L14 may be aspherical.

  The second lens group G2 is composed of, for example, three lenses L21 to L23. For example, both the lens L21 and the lens L22 have a biconcave shape. The lens L23 is, for example, a positive meniscus lens (Example 1) having a convex surface directed toward the object side. Alternatively, the lens L23 may be a biconvex lens as in the second embodiment. In any case, the lens L22 and the lens L23 constitute a cemented lens.

  In the third lens group G3, a G31 group having a positive refractive power, a G32 group having a positive refractive power, an aperture stop St, and a G33 group having a positive or negative refractive power are arranged in this order from the object side. It is a thing.

  The G31 group includes, for example, a single lens L31 having at least one aspheric surface. The lens L31 is, for example, a meniscus lens having a convex surface facing the object side in the vicinity of the optical axis Z1. Both surfaces S14 and S15 of the lens L31 are preferably aspheric. In that case, the object-side surface S14 has an aspherical shape in which the positive refractive power decreases as it moves away from the optical axis Z1 toward the peripheral portion, and the image-side surface S15 moves away from the optical axis Z1 toward the peripheral portion. An aspherical shape that weakens the negative refractive power is particularly desirable.

  The G32 group includes, for example, a single lens L32 having at least one aspheric surface. The lens L32 has, for example, a biconvex shape in the vicinity of the optical axis Z1. Both surfaces S16 and S17 of the lens L32 are preferably aspheric. In particular, it is desirable that the object-side surface S16 has an aspherical shape that increases the positive refractive power toward the peripheral edge away from the optical axis Z1. The G32 group (lens L32) is an anti-vibration moving group that moves in a direction perpendicular to the optical axis Z1 to correct image blur caused by vibration.

  The G33 group is a cemented lens including, for example, a lens L33 having a positive refractive power and a lens L34 having a negative refractive power. In Example 1, the lens L33 has a biconvex shape, and the lens L34 has a biconcave shape, so that the entire G33 group has a positive refractive power. On the other hand, in Example 2, the lens L33 is a positive meniscus lens having a convex surface facing the object side, and the lens L34 is a negative meniscus lens having a convex surface facing the object side. Has to have.

  In the fourth lens group G4, for example, a lens L41 and a lens L42 that form a cemented lens, and a lens L43 are sequentially arranged from the object side. The lens L41 is, for example, a positive meniscus lens having a convex surface facing the object side, and the lens L42 is, for example, a negative meniscus lens having a convex surface facing the object side. In the lens L43, for example, both surfaces S25 and S26 are aspheric, and have a biconvex shape in the vicinity of the optical axis Z1.

Further, this zoom lens is preferably configured to satisfy both the following conditional expressions (1) and (2). However, the focal length of the third lens group G3 is f3, the focal length of the entire system at the wide angle end is fw, and the focal length of the G32 group is f32.
3.0 <f3 / fw <5.0 (1)
1.2 <f32 / f3 <2.0 (2)

  Next, operations and effects of the zoom lens according to the present embodiment configured as described above will be described.

  In the zoom lens according to the present embodiment, the third lens group G3 is configured by sequentially arranging a positive G31 group, a positive G32 group, and a positive or negative G33 group from the object side. In the third lens group G3 having such a configuration, since the G31 group has a positive refractive power, the diameter of the light beam that is transmitted through the G31 group and then enters the G32 group is reduced. Accordingly, the diameter of the lens L32 is also increased. It's small. Further, since the G32 group also has a positive refractive power, the diameter of the light beam that passes through the G32 group and then enters the G33 group is reduced. Therefore, the diameters of the lenses L33 and L34 of the G33 group can be reduced. Therefore, the overall configuration of the third lens group G3 is made compact, and it is smaller and lighter than the first lens group G1 and the second lens group G2. When correcting image blur due to vibration, the light and small G32 group consisting of a single lens L32 is moved in the direction perpendicular to the optical axis Z1, so the burden on the drive mechanism is reduced. Can be reduced. Therefore, it is advantageous for downsizing the drive mechanism.

  Further, since the third lens group G3 is divided into three groups of the G31 group, the G32 group, and the G33 group, it is easy to appropriately set the eccentricity sensitivity of the G32 group that moves during image blur correction. . When at least one aspheric surface is provided in each of the G31 group and the G32 group, the lens configuration of the G31 group and the G32 group is simplified, which is advantageous for further downsizing the entire third lens group G3. . In particular, an aspherical shape is formed such that the surface S14 moves away from the optical axis Z1 toward the peripheral edge, and the positive refractive power is weakened. The surface S15 moves away from the optical axis Z1 toward the peripheral edge, and the negative refractive power is reduced. The lens L31 is configured to have such an aspherical shape, and the lens L32 is configured to have an aspherical shape that increases the positive refractive power as the surface S16 moves away from the optical axis Z1 toward the peripheral edge. In this case, the occurrence of decentering coma during image blur correction is reduced, and various aberrations are corrected even better in cases other than image blur correction. Further, by making the G33 group a cemented lens composed of a positive lens L33 and a negative lens L34, the occurrence of chromatic aberration is suppressed.

  Further, when the conditional expression (1) is satisfied, the refractive power of the third lens group G3 is optimized, and both the securing of the back focus and the shortening of the total lens length are achieved. Conditional expression (1) represents an appropriate range of an amount (f3 / fw) representing the magnitude of the refractive power (1 / f3) of the third lens group G3 with respect to the refractive power (1 / fw) of the entire system at the wide-angle end. Is an expression. Here, if the positive refractive power of the third lens G3 becomes too strong below the lower limit of the conditional expression (1), the overall lens length can be shortened, but the back focus cannot be ensured sufficiently. On the other hand, if the upper limit of conditional expression (1) is exceeded and the positive refractive power of the third lens group G3 becomes too weak, the total lens length increases and it becomes difficult to make the lens compact.

  If conditional expression (2) is further satisfied, at the time of image blur correction, both reduction in the amount of movement of the G32 group (lens L32) and optimization of eccentricity sensitivity are achieved. Conditional expression (2) represents an appropriate range of an amount (f32 / f3) representing the magnitude of the refractive power (1 / f32) of the G32 group with respect to the refractive power (1 / f3) of the third lens group G3. . Here, if the positive refractive power of the G32 group becomes too strong below the lower limit of the conditional expression (2), the decentering sensitivity at the time of image blur correction becomes high and the image is deteriorated. On the other hand, if the upper limit of conditional expression (2) is exceeded and the positive refractive power of the G32 group becomes too weak, the amount of movement of the G32 group required for image blur correction increases, leading to an increase in the size of the third lens group G3. End up.

  For this reason, the zoom lens according to the present embodiment exhibits a good image blur correction function, and the entire configuration of the third lens group G3 is made more compact.

  Next, specific numerical examples of the zoom lens according to the present embodiment will be described.

  Hereinafter, the first and second numerical examples (Examples 1 and 2) will be described together. 3 to 5 show a first numerical example, and show specific lens data corresponding to the cross-sectional configuration of the zoom lens shown in FIGS. 1 (A) and 1 (B). 6 to 8 show a second numerical example, which corresponds to the cross-sectional configuration of the zoom lens shown in FIGS. 2 (A) and 2 (B). 3 and 6 show basic data portions of the lens data of each embodiment, and FIGS. 4 and 7 show data portions relating to the aspherical shape of the lens data of each embodiment.

  In the column of surface number Si in the basic lens data shown in FIG. 3 and FIG. 6, the zoom lens of each embodiment corresponds to the symbol Si shown in FIG. 1 and FIG. The number of the i-th surface (i = 1 to 28) is shown, with the element surface being first and sequentially increasing toward the image side. In the column of the radius of curvature Ri, the value of the radius of curvature of the i-th surface from the object side is shown in correspondence with the symbol Ri shown in FIGS. Also in the column of the surface interval Di, the interval on the optical axis between the i-th surface Si and the i + 1-th surface Si + 1 from the object side is shown in correspondence with the reference numerals given in FIGS. The unit of the value of the curvature radius Ri and the surface interval Di is millimeter (mm). In the columns Ndj and νdj, the refractive index and the Abbe number for the d-line (587.6 nm) of the j-th lens element (j = 1 to 15) from the object side, including the optical member GC, are shown. . In addition, although the value of the curvature radii R27 and R28 of both surfaces of the filter GC is 0 (zero), this indicates a flat surface. Further, the column of the diaphragm surface interval Di indicates the distance (mm) between the diaphragm St and the surface S19 on the optical axis. 3 and 6 show values of the focal length f (mm), F number (FNO.), And angle of view 2ω (°) of the entire system as various data.

  In the zoom lenses according to the first and second embodiments, the distance between the fourth lens group G4, the third lens group G3, and the image plane Simg changes during focusing. The value when in-focus is shown.

  Furthermore, in the zoom lenses of Examples 1 and 2, since the second lens group G2 and the fourth lens group G4 move on the optical axis Z1 with zooming, the first lens group G1 and the second lens group G2 A surface distance D8 between the second lens group G2 and the third lens group G3, a surface distance D21 between the third lens group G3 and the fourth lens group G4, and a fourth lens group G4. Each value of the surface distance D26 between the optical member GC and the optical member GC is variable. 5 and 8 show values at the wide-angle end, the intermediate end, and the telephoto end, with the data at the time of zooming of these surface intervals D8, D13, D21, D26 as other data. FIGS. 5 and 8 also show the values (mm) of the focal length f at the wide-angle end, the intermediate position, and the telephoto end.

  3 and 6, the symbol “*” given to the left of the surface number Si indicates that the lens surface has an aspherical shape. In each embodiment, all the surfaces of the lens L14, the lens L31, the lens L32, and the lens L43 are aspherical. In the basic lens data, the numerical value of the radius of curvature near the optical axis (near the paraxial axis) is shown as the radius of curvature of these aspheric surfaces.

  Each aspherical data in FIG. 4 and FIG. 7 describes the values of the coefficients Ai and KA in the aspherical shape expression represented by the following expression (ASP). More specifically, Z is the length (mm) of a perpendicular line drawn from a point on the aspheric surface at a height h from the optical axis to the tangential plane (plane perpendicular to the optical axis) of the apex of the aspheric surface. Show.

Z = C · h ² / {1+ (1−KA · C ² · h ² ) ^1/2 } + A ₃ · h ³ + A ₄ · h ⁴ + A ₅ · h ⁵ + A ₆ · h ⁶ + A ₇ · h ⁷ + A ₈・ h ⁸ + A ₉・ h ⁹ + A ₁₀・ h ¹⁰ …… (ASP)
However,
Z: Depth of aspheric surface (mm)
h: Distance from the optical axis to the lens surface (height) (mm)
KA: eccentricity C: paraxial curvature = 1 / R
(R: paraxial radius of curvature)
Ai: i-th order (i = integer greater than or equal to 3) aspheric coefficient

In each of the embodiments, all of the aspheric shapes in the lens L14, the lens L31, the lens L32, and the lens L43 are even-order coefficients A ₄ , A ₆ , A ₈ , A ₁₀ (partly A ₁₂ ) as aspheric coefficients. In addition, odd-numbered aspheric coefficients A ₃ , A ₅ , A ₇ and A ₉ (partly A ₁₁ ) are also effectively used.

  FIG. 9 collectively shows values corresponding to the conditional expressions (1) and (2) described above for each example. As shown in FIG. 9, the values of the respective examples are all within the numerical ranges of the conditional expressions (1) and (2).

  FIGS. 10A to 10D respectively show spherical aberration, astigmatism, distortion (distortion aberration), and lateral chromatic aberration at the wide angle end in the zoom lens of Example 1. FIGS. 11 (A) to 11 (D) show similar aberrations in the intermediate range, respectively. 12 (A) to 12 (D) show similar aberrations at the telephoto end, respectively. Each aberration diagram shows the aberration with the d-line as the reference wavelength, while the spherical aberration diagram also shows aberrations for the light ray having a wavelength of 460.0 nm and the light ray having a wavelength of 615.0 nm. In the astigmatism diagram, the solid line indicates the sagittal direction and the broken line indicates the tangential direction. In the astigmatism diagram, the distortion diagram, and the lateral chromatic aberration diagram, ω represents a half angle of view.

  Similarly, various aberrations for Example 2 are shown in FIGS. 13A to 13D for the wide angle end, FIGS. 14A to 14D for the intermediate range, and about the telephoto end. Shown in FIGS. 15 (A) to 15 (D).

  As is apparent from the lens data and aberration diagrams described above, extremely good aberration performance is exhibited for each example. At the same time, the overall length has been reduced.

  The present invention has been described above with reference to some embodiments and examples. However, the present invention is not limited to the above embodiments and examples, and various modifications can be made. For example, the values of the radius of curvature, the surface interval, and the refractive index of each lens component are not limited to the values shown in the above numerical examples, but can take other values. In the above-described embodiments and examples, the first sub-lens group (G31 group) and the second sub-lens group (G32 group) are each composed of a single lens so that both surfaces are aspheric. However, the present invention is not limited to this.

  In the present invention, a reflecting surface for constituting the bending optical system may be provided in the first lens group. FIG. 16 shows a modification of the zoom lens shown in FIG. 1, and a right-angle prism having a reflecting surface RS is adopted as the optical path conversion element of the lens L12. By doing so, a bending zoom lens in which the optical path is bent by the reflecting surface RS can be configured, and the overall thickness can be reduced.

1 is a cross-sectional view illustrating a first configuration example of a zoom lens according to an embodiment of the present invention and corresponding to Example 1. FIG. FIG. 3 is a cross-sectional view illustrating a second configuration example of a zoom lens according to an embodiment of the present invention and corresponding to Example 2; FIG. 3 is an explanatory diagram showing basic lens data in the zoom lens of Example 1; FIG. 3 is an explanatory diagram illustrating data relating to an aspheric surface in the zoom lens according to the first exemplary embodiment. FIG. 6 is an explanatory diagram showing other data in the zoom lens of Example 1; FIG. 6 is an explanatory diagram showing basic lens data in a zoom lens of Example 2. FIG. 6 is an explanatory diagram showing data relating to an aspheric surface in the zoom lens of Example 2. FIG. 6 is an explanatory diagram showing other data in the zoom lens of Example 2. FIG. 6 is an explanatory diagram illustrating numerical values corresponding to conditional expressions (1) and (2) in each zoom lens of Examples 1 and 2; FIG. 3 is an aberration diagram illustrating spherical aberration, astigmatism, distortion, and lateral chromatic aberration at the wide-angle end in the zoom lens according to the first exemplary embodiment. FIG. 3 is an aberration diagram illustrating spherical aberration, astigmatism, distortion, and lateral chromatic aberration in the intermediate range in the zoom lens according to the first exemplary embodiment. FIG. 6 is an aberration diagram illustrating spherical aberration, astigmatism, distortion, and lateral chromatic aberration at the telephoto end in the zoom lens of Example 1; FIG. 7 is an aberration diagram illustrating spherical aberration, astigmatism, distortion, and lateral chromatic aberration at the wide-angle end in the zoom lens according to Example 2; FIG. 6 is an aberration diagram showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration in the intermediate range in the zoom lens according to Example 2; FIG. 6 is an aberration diagram illustrating spherical aberration, astigmatism, distortion, and lateral chromatic aberration at the telephoto end in the zoom lens according to Example 2; It is sectional drawing in the modification of the zoom lens shown in FIG.

Explanation of symbols

G1 to G4: 1st lens group to 4th lens group, G31 to G33: 1st sub lens group to 3rd sub lens group, Si: i th lens surface from the object side, Ri: i th lens from the object side The radius of curvature of the lens surface, Di: the surface distance between the i-th and (i + 1) -th lens surfaces from the object side, Z1,.

Claims (8)

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 fourth lens group having a positive refractive power are arranged on the object side. Prepare in order from
The zooming operation is performed by moving the second lens group on the optical axis, and the correction and focusing of the image plane variation by the zooming operation are performed by moving the fourth lens group on the optical axis. Configured to do and
The third lens group includes a first sub lens group having a positive refractive power, a second sub lens group having a positive refractive power, and a third sub lens group having a positive or negative refractive power on the object side. Are arranged in order from
A zoom lens with an image blur correction function, wherein the entire second sub lens group is moved in a direction perpendicular to the optical axis so as to correct image blur due to vibration. 2. The zoom lens with an image blur correction function according to claim 1, wherein a reflection surface for constituting a bending optical system is provided in the first lens group. The first lens group includes, in order from the object side, at least one negative lens, a reflecting member having the reflecting surface, and at least one positive lens. Zoom lens with image blur correction function. The image blur correction function according to any one of claims 1 to 3, further comprising: satisfying both the following conditional expression (1) and conditional expression (2): Zoom lens.
3.0 <f3 / fw <5.0 (1)
1.2 <f32 / f3 <2.0 (2)
However,
f3: focal length of the third lens unit fw: focal length of the entire system at the wide angle end f32: focal length of the second sub lens unit   5. The image blur correction function according to claim 1, wherein each of the first sub lens group and the second sub lens group has at least one aspheric surface. Zoom lens.   6. The zoom lens with an image blur correction function according to claim 1, wherein each of the first sub lens group and the second sub lens group includes a single lens. The single lens constituting the first sub-lens group has an aspherical shape in which the positive refractive power is weakened as the object-side surface moves away from the optical axis toward the periphery, and the image-side surface is light. It is configured to form an aspherical shape that weakens the negative refractive power as it goes away from the axis toward the periphery,
The single lens constituting the second sub-lens group is configured to have an aspherical shape that increases the positive refractive power as the object side surface moves away from the optical axis toward the peripheral edge. The zoom lens with an image blur correction function according to claim 6. 8. The zoom lens with an image blur correction function according to claim 1, wherein the third sub lens group includes a cemented lens configured by a positive lens and a negative lens. 9.

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