Zoom lens and image pickup apparatus

Abstract

Provided is a zoom lens that is small and light, has a large image circle, and has high optical performance, and an imaging device provided with the zoom lens. The zoom lens includes, in order from an object side toward an image side, a first lens group having a negative refractive power, an intermediate group, and a final group. During zooming, the interval between the first lens group and the intermediate group changes, and the interval between the intermediate group and the final group changes. During focusing, at least a part of the intermediate group moves, and the first lens group and the final group are fixed relative to the image plane. The zoom lens satisfies predetermined conditional expressions related to the back focal length, the focal length, and the maximum half viewing angle.

Description

Technical Field

[0001] The present invention relates to a zoom lens and a camera device. Background Technology

[0002] As a zoom lens applicable to imaging devices such as digital cameras and camcorders, for example, the lens system described in Patent Document 1 below is known.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2020-140142

[0004] In recent years, there has been a demand for small and lightweight zoom lenses with large image circles and high optical performance. Summary of the Invention

[0005] The present invention was made in view of the above circumstances, and its object is to provide a small and lightweight zoom lens with a large image circle and high optical performance, and a camera device having the zoom lens.

[0006] The zoom lens of one aspect of the present invention includes, from the object side to the image side, a first lens group with negative refractive power, an intermediate group, and a final group. During zooming, the interval between the first lens group and the intermediate group changes, and the interval between the intermediate group and the final group changes. During focusing, at least a portion of the intermediate group moves along the optical axis as a focusing group. The first lens group and the final group are fixed relative to the image plane. When the back focal length of the entire system at the air equivalent distance of the wide-angle end in the state of focusing on an infinity object is set to Bfw, the focal length of the entire system at the wide-angle end in the state of focusing on an infinity object is set to fw, and the maximum half angle of view at the wide-angle end in the state of focusing on an infinity object is set to ωw, the zoom lens satisfies the following condition (1).

[0007] 0.35<Bfw / (fw×tan|ωw|)<1.5 (1).

[0008] The zoom lens described above preferably satisfies the following condition (1-1), and more preferably satisfies the following condition (1-2).

[0009] 0.45<Bfw / (fw×tan|ωw|)<1.1 (1-1)

[0010] 0.5<Bfw / (fw×tan|ωw|)<0.85 (1-2)

[0011] When the movement of the focusing group at the telephoto end is changed from focusing on an infinity object to a magnification of -0.1x, and the difference in the optical axis direction between the position of the lens surface closest to the object in the middle group at the telephoto end and the position of the lens surface closest to the object in the middle group at the wide-angle end is set as DpM, the zoom lens of the above method preferably satisfies the following condition (2).

[0012] 0.005<|Dfoct / DpM|<0.3 (2).

[0013] When the effective diameter of the lens surface closest to the object in the intermediate group is set to EDMf, and the effective diameter of the lens surface closest to the image in the intermediate group is set to EDMr, the zoom lens of the above method preferably satisfies the following condition (3).

[0014] 0.3 < EDMf / EDMr < 1.5 (3).

[0015] When the sum of the distance on the optical axis from the lens surface closest to the object side of the first lens group at the wide-angle end to the lens surface closest to the image side of the final lens group at the wide-angle end, and Bfw, is set as TLw, the zoom lens of the above method preferably satisfies the following condition (4).

[0016] 2.5<TLw / (fw×tan|ωw|)<7 (4).

[0017] Preferably, the intermediate group includes, from the object side to the image side, an anterior portion with positive refractive power and a posterior portion with negative refractive power.

[0018] Let d be the angle between the normal to the lens surface at the effective diameter end of the lens surface and the optical axis, and let α be in degrees.

[0019] The rear portion preferably includes one or more convex lens surfaces facing the air that satisfy the following condition (5).

[0020] 13<|α|<50 (5).

[0021] An aperture is positioned on the side closest to the object in the middle group or inside the middle group. When the distance on the optical axis from the aperture at the wide-angle end to the aforementioned convex lens surface is set to DStw, and the focal length of the rear part of the wide-angle end group when focusing on an object at infinity is set to fMrw,

[0022] The rear portion preferably includes one or more of the aforementioned convex lens surfaces that satisfy the following condition (6).

[0023] 0.05<DStw / |fMrw|<2.5 (6).

[0024] When the height of the principal ray with the maximum image height on the image-side lens surface of the front part group of the wide-angle end when focusing on an object at infinity is set to HMfb, the height of the axial edge ray on the image-side lens surface of the front part group of the wide-angle end when focusing on an object at infinity is set to HMfa, the height of the principal ray with the maximum image height on the image-side lens surface of the rear part group of the wide-angle end when focusing on an object at infinity is set to HMrb, and the height of the axial edge ray on the image-side lens surface of the rear part group of the wide-angle end when focusing on an object at infinity is set to HMra, the zoom lens of the above configuration preferably satisfies the following condition (7).

[0025] 0.08<(HMfb / HMfa) / (HMrb / HMra)<0.8 (7).

[0026] It can be configured such that, during focusing, at least a portion of the rear group moves along the optical axis, while the other groups remain fixed relative to the image plane.

[0027] It can be configured such that, during focusing, at least a portion of the front group moves along the optical axis, while the other groups remain fixed relative to the image plane.

[0028] Preferably, the rear portion group includes an image-side negative lens whose image-side surface is convex. In this case, it is preferable that the rear portion group includes an object-side negative lens whose object-side surface is convex, located further from the object side than the image-side negative lens.

[0029] When the paraxial radius of curvature of the lens surface closest to the object in the front part group is set to RMff, and the paraxial radius of curvature of the lens surface closest to the image in the front part group is set to RMfr, the zoom lens of the above method preferably satisfies the following condition (8).

[0030] -1<(RMff+RMfr) / (RMff-RMfr)<1 (8).

[0031] When the distance from the image plane at the wide-angle end to the exit pupil position is set to Pexpw when the lens is focused on an object at infinity, the zoom lens described above preferably satisfies the following condition (9).

[0032] 0.5 < Pexpw / fw < 5 (9).

[0033] The first lens group is a negative meniscus lens with a convex surface on the object side, including the object side surface. When the paraxial radius of curvature of the object side surface of the negative meniscus lens is set to R1f and the paraxial radius of curvature of the image side surface of the negative meniscus lens is set to R1r, the zoom lens of the above-described manner preferably satisfies the following condition (10).

[0034] 1<(R1f+R1r) / (R1f-R1r)<6 (10).

[0035] Preferably, the first lens group includes two or more negative meniscus lenses whose object-side surfaces are convex.

[0036] When the refractive index of the positive lens included in the first lens group relative to the d-line is set to N1p, the first lens group preferably includes one or more positive lenses that satisfy the following condition (11).

[0037] 1.6 < N1p < 2.15 (11).

[0038] When the focal length of the first lens group is set to f1, the zoom lens of the above method preferably satisfies the following condition (12).

[0039] 0.3 < fw / |f1| < 1.5 (12).

[0040] When the focal length of the middle group at the wide-angle end is set to fMw when focusing on an object at infinity, the zoom lens described above preferably satisfies the following condition (13).

[0041] 0.4 < fw / fMw < 1.5 (13).

[0042] When the focal length of the focusing group is set to ffoc, the zoom lens described above preferably satisfies the following condition (14).

[0043] 0.05<fw / |ffoc|<2.5 (14).

[0044] When the average weight of all lenses included in the intermediate group is set to GMave, the zoom lens of the above method preferably satisfies the following condition (15).

[0045] 3 < GMave < 4.2 (15).

[0046] The temperature coefficient of the relative refractive index with respect to the d-line within the range of 20°C to 40°C for the negative lenses included in the first lens group is set as (dN1n / dT)×10. -6 Set the unit of dN1n / dT to K (Kelvin). -1 In this case,

[0047] The first lens group preferably includes one or more negative lenses that satisfy the following condition (16).

[0048] -15<dN1n / dT<0 (16).

[0049] Preferably, during zooming, the final group is fixed relative to the image plane.

[0050] Another aspect of the present invention relates to a camera device that includes the zoom lens of the present invention.

[0051] In addition, the terms "including" and "including" in this specification mean that, in addition to the constituent elements listed, it may also include lenses that do not substantially have refractive power, as well as optical elements other than lenses such as apertures, filters and cover glass, and mechanism parts such as lens flanges, lens barrels, imaging elements and hand shaking correction mechanisms.

[0052] In this specification, "a group with positive refractive power" means that the group as a whole has positive refractive power. Similarly, "a group with negative refractive power" means that the group as a whole has negative refractive power. "A lens with positive refractive power" and "a positive lens" have the same meaning. "A lens with negative refractive power" and "a negative lens" have the same meaning. "First lens group," "intermediate group," "front part group," "rear part group," "final group," "focusing group," and "vibration damping group" are not limited to structures including multiple lenses; they can also be structures including only one lens.

[0053] "Single lens" refers to an unjoined single lens. However, a compound aspherical lens (a lens in which a spherical lens and an aspherical film formed on the spherical lens are integrated to function as a single aspherical lens) is used as a single lens and not considered a joined lens. Unless otherwise specified, the sign of the refractive power and surface shape associated with lenses including aspherical surfaces uses the sign of the refractive power and surface shape of the paraxial region. Regarding the sign of the radius of curvature, the radius of curvature of the surface with the convex side facing the object is set to positive, and the radius of curvature of the surface with the convex side facing the image is set to negative.

[0054] In this specification, "the entire system" refers to the zoom lens. "Back focal length at air equivalent distance" is the air equivalent distance along the optical axis from the image-side lens surface to the image plane. "Focal length" used in the conditional expressions is the paraxial focal length. The values ​​used in the conditional expressions are based on the d-line when focusing on an object at infinity. "tan" used in the conditional expressions is the tangent.

[0055] The "d-line," "C-line," "F-line," and "g-line" described in this specification refer to bright lines. In this specification, the wavelength of the d-line is considered to be 587.56 nm, the wavelength of the C-line is considered to be 656.27 nm, the wavelength of the F-line is considered to be 486.13 nm, and the wavelength of the g-line is considered to be 435.84 nm. When the refractive indices of a lens relative to the g-line, F-line, and C-line are respectively set as Ng, NF, and NC, the partial dispersion ratio θgF between the g-line and F-line of the lens is defined as θgF = (Ng - NF) / (NF - NC).

[0056] Invention Effects

[0057] According to the present invention, it is possible to provide a small and lightweight zoom lens with a large image circle and high optical performance, and an imaging device having the zoom lens. Attached Figure Description

[0058] Figure 1 Corresponding to the zoom lens of Embodiment 1, this is a cross-sectional view and a diagram showing the structure and movement trajectory of the zoom lens according to an embodiment.

[0059] Figure 2 It means Figure 1 The diagram shows the structure and beam of the zoom lens at various zoom levels.

[0060] Figure 3 This is a diagram used to illustrate Dfoct.

[0061] Figure 4 This is a diagram used to illustrate the effective diameter.

[0062] Figure 5 This is a diagram used to illustrate α.

[0063] Figure 6 This is a diagram used to illustrate the notation of condition (7).

[0064] Figure 7 This is a diagram of the aberrations of the zoom lens in Example 1.

[0065] Figure 8 This is a cross-sectional view and a diagram showing the movement trajectory of the zoom lens in Embodiment 2.

[0066] Figure 9 This is a diagram of the aberrations of the zoom lens in Example 2.

[0067] Figure 10 This is a cross-sectional view and a diagram showing the movement trajectory of the zoom lens in Embodiment 3.

[0068] Figure 11 These are aberration diagrams of the zoom lens in Example 3.

[0069] Figure 12 This is a cross-sectional view and a diagram showing the movement trajectory of the zoom lens in Embodiment 4.

[0070] Figure 13 This is a diagram of the aberrations of the zoom lens in Example 4.

[0071] Figure 14 This is a cross-sectional view and a diagram showing the movement trajectory of the zoom lens in Embodiment 5.

[0072] Figure 15These are aberration diagrams of the zoom lens in Example 5.

[0073] Figure 16 This is a cross-sectional view and a diagram showing the movement trajectory of the zoom lens in Embodiment 6.

[0074] Figure 17 These are aberration diagrams of the zoom lens in Example 6.

[0075] Figure 18 This is a cross-sectional view and a diagram showing the movement trajectory of the zoom lens in Embodiment 7.

[0076] Figure 19 This is a diagram of the aberrations of the zoom lens in Example 7.

[0077] Figure 20 This is a cross-sectional view and a diagram showing the movement trajectory of the zoom lens in Embodiment 8.

[0078] Figure 21 This is a cross-sectional view and a diagram showing the structure and movement trajectory of the zoom lens of Embodiment 8A.

[0079] Figure 22 These are aberration diagrams of the zoom lens in Example 8.

[0080] Figure 23 This is a cross-sectional view and a diagram showing the structure and movement trajectory of the zoom lens of Embodiment 9.

[0081] Figure 24 These are aberration diagrams of the zoom lens in Example 9.

[0082] Figure 25 This is a cross-sectional view and a diagram showing the movement trajectory of the zoom lens of Embodiment 10.

[0083] Figure 26 These are aberration diagrams of the zoom lens in Example 10.

[0084] Figure 27 This is a perspective view of the front side of a camera device according to one embodiment.

[0085] Figure 28 This is a perspective view of the rear side of a camera device according to one embodiment. Detailed Implementation

[0086] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0087] Figure 1 The diagram shows a cross-sectional view and movement trajectory of the structure of the wide-angle end of a zoom lens according to an embodiment of the present invention. Figure 2 The diagram shows the structure and cross-sectional view of the beam in each zoom state of the zoom lens. Figure 1 and Figure 2 The example shown corresponds to the zoom lens of Embodiment 1 described later. Figure 1 and Figure 2 The image shows the state of focusing on an object at infinity; the left side is the object side, and the right side is the image side. Figure 2 In the diagram, the upper section labeled "WIDE" indicates the wide-angle end, the middle section labeled "MIDDLE" indicates the intermediate focal length end, and the lower section labeled "TELE" indicates the telephoto end. Figure 2 In the diagram, the on-axis beam wa and beam wb with maximum image height are shown as beams at the wide-angle end, the on-axis beam ma and beam mb with maximum image height at the intermediate focal length, and the on-axis beam ta and beam tb with maximum image height at the telephoto end. The following primarily refers to... Figure 1 A zoom lens according to one embodiment of the present invention will be described.

[0088] One embodiment of the present invention relates to a zoom lens that, from the object side to the image side, sequentially comprises a first lens group G1 with negative refractive power, an intermediate lens group GM, and a final lens group GE. During zooming, the interval between the first lens group G1 and the intermediate lens group GM changes, as does the interval between the intermediate lens group GM and the final lens group GE. By using a lens system with a negative lens in front, the entrance pupil can be positioned closer to the object side, thus facilitating the assurance of peripheral light.

[0089] The intermediate group GM is a group that includes one or more lens groups. The number of lens groups included in the intermediate group GM can be arbitrarily set, but for miniaturization and weight reduction, one, two, or three is preferred. Furthermore, for miniaturization and weight reduction, the final group GE preferably includes one lens group. Additionally, in this specification, "lens group" refers to a component of a zoom lens, which includes at least one lens separated by air gaps that change during zooming. During zooming, the lens group moves or remains stationary, and the spacing between lenses within a lens group remains constant.

[0090] During focusing, at least a portion of the intermediate group GM moves along the optical axis Z as a focusing group, while the first lens group G1 and the final group GE remain fixed relative to the image plane Sim. In this specification, the group that moves during focusing is referred to as the "focusing group." Focusing is achieved by moving the focusing group. Using lenses from the relatively small-diameter intermediate group GM to form the focusing group facilitates miniaturization of the focusing unit and also contributes to overall miniaturization.

[0091] The intermediate group GM can be configured such that, from the object side to the image side, it successively includes an anterior portion GMf with positive refractive power and a posterior portion GMr with negative refractive power. In this case, it is beneficial to suppress performance changes during magnification.

[0092] As an example, Figure 1 The zoom lens, along the optical axis Z from the object side to the image side, includes lens group 1 G1, lens group 2 G2, lens group 3 G3, and lens group 4 G4 in sequence. Each of these groups... Figure 1 The correspondences between the examples are as follows: The middle group GM includes the second lens group G2 and the third lens group G3. The front part group GMf corresponds to the second lens group G2. The rear part group GMR corresponds to the third lens group G3. The final group GE corresponds to the fourth lens group G4.

[0093] Figure 1 The lens groups are configured as follows: Lens group 1 G1 consists of four lenses L11 to L14, arranged sequentially from the object side to the image side. Lens group 2 G2 consists of four lenses, arranged sequentially from the object side to the image side: aperture St and lenses L21 to L24. Lens group 3 G3 consists of two lenses, L31 and L32, arranged sequentially from the object side to the image side. Lens group 4 G4 consists of lens L41. Additionally, Figure 1 The aperture St shown indicates the position along the optical axis, not the shape.

[0094] exist Figure 1 The image illustrates an example where a parallel flat optical component PP is positioned between the zoom lens and the image plane Sim, assuming a zoom lens is used in a camera device. The optical component PP is assumed to be a component such as various filters and / or cover glass. These filters include low-pass filters, infrared cutoff filters, and / or filters that cut off specific wavelength regions. The optical component PP is a component without refractive power. The camera device can also be constructed by omitting the optical component PP.

[0095] exist Figure 1 In the example, during zooming, the first lens group G1, the second lens group G2, and the third lens group G3 change their spacing along the optical axis Z from that of adjacent lens groups, while the fourth lens group G4 remains fixed relative to the image plane Sim. Figure 1 In the image, below the lens group that moves during zooming, a curved arrow or diagonal arrow is shown to indicate the approximate movement trajectory when zooming from the wide-angle end to the telephoto end; below the lens group that is fixed during zooming, a grounding mark is shown.

[0096] exist Figure 1 In the example, during focusing, the third lens group G3 moves along the optical axis Z, while the other lens groups remain fixed relative to the image plane Sim. That is, in Figure 1 In the example, the focusing group includes the third lens group G3. Figure 1 The horizontal arrow pointing to the right below the third lens group G3 indicates that when focusing from an object at infinity to a closer object, the third lens group G3 is a focusing group that moves towards the image side.

[0097] Next, the preferred structure and feasible structure of the zoom lens of the present invention will be described. In addition, in the following description of the preferred structure and feasible structure, in order to avoid length, "the zoom lens of the present invention" will be simply referred to as "zoom lens".

[0098] When the back focal length of the entire system at the air equivalent distance of the wide-angle end is set to Bfw, the focal length of the entire system at the wide-angle end is set to fw, and the maximum half angle of view at the wide-angle end is set to ωw, the zoom lens preferably satisfies the following condition (1). Figure 2 An example of ωw is shown. By ensuring that the corresponding value of condition (1) is not below the lower limit, the back focal length will not become too short relative to the image circle, thus facilitating the miniaturization of the final GE group. By ensuring that the corresponding value of condition (1) is not above the upper limit, the back focal length will not become too long relative to the image circle, thus facilitating the shortening of the overall length. To obtain better characteristics, the zoom lens more preferably satisfies the following condition (1-1), and even more preferably satisfies the following condition (1-2).

[0099] 0.35<Bfw / (fw×tan|ωw|)<1.5 (1)

[0100] 0.45<Bfw / (fw×tan|ωw|)<1.1 (1-1)

[0101] 0.5<Bfw / (fw×tan|ωw|)<0.85 (1-2)

[0102] When the movement of the focus group at the telephoto end when changing from focusing on an infinity object to a magnification of -0.1x is defined as Dfoct, and the difference in the optical axis direction between the position of the lens surface closest to the object in the middle group GM at the telephoto end when focusing on an infinity object and the position of the lens surface closest to the object in the middle group GM at the wide-angle end is defined as DpM, the zoom lens preferably satisfies the following condition (2). As an example, Figure 2 DpM is shown in the figure. Figure 3 Dfoct is shown in the image. Figure 3The upper section shows the state of focusing on an object at infinity at the telephoto end, and the lower section shows the state of a magnification of -0.1x at the telephoto end. By ensuring that the corresponding value of condition (2) is not below the lower limit, the strictness of the positional accuracy of the focus group during focusing can be suppressed, thus making it easy to control. By ensuring that the corresponding value of condition (2) is not above the upper limit, the amount of movement of the focus group during focusing can be suppressed. As a result, the large size of the focusing unit can be suppressed, thus contributing to the overall miniaturization and weight reduction. To obtain better characteristics, the zoom lens more preferably satisfies the following condition (2-1), and even more preferably satisfies the following condition (2-2).

[0103] 0.005 < |Dfoct / DpM| < 0.3 (2)

[0104] 0.015<|Dfoct / DpM|<0.15 (2-1)

[0105] 0.03<|Dfoct / DpM|<0.115 (2-2)

[0106] When the effective diameter of the lens surface closest to the object in the intermediate group GM is set to EDMf, and the effective diameter of the lens surface closest to the image in the intermediate group GM is set to EDMr, the zoom lens preferably satisfies the following condition (3). Typically, the focusing unit is located radially outward from the effective diameter of the intermediate group GM. Therefore, the greater the difference between the effective diameter of the lens surface closest to the object in the intermediate group GM and the effective diameter of the lens surface closest to the image in the intermediate group GM, the larger the focusing unit becomes. Therefore, by satisfying condition (3), the large size of the focusing unit can be suppressed, thus facilitating overall miniaturization and weight reduction. To obtain better characteristics, the zoom lens more preferably satisfies the following condition (3-1), and even more preferably satisfies the following condition (3-2).

[0107] 0.3 < EDMf / EDMr < 1.5 (3)

[0108] 0.4 < EDMf / EDMr < 1 (3-1)

[0109] 0.5 < EDMf / EDMr < 0.85 (3-2)

[0110] Furthermore, in the technology of this invention, the "effective diameter" of the lens surface is defined as twice the distance from the point where the outermost ray of light incident from the object side onto the lens surface intersects with the lens surface to the optical axis Z. Here, "outer side" refers to the radially outer side centered on the optical axis Z, that is, the side away from the optical axis Z. Moreover, the "outermost ray" is determined considering the entire magnification region.

[0111] As an illustrative diagram Figure 4 An example of the effective diameter ED is shown in the figure. Figure 4 In the image, the left side is the object side, and the right side is the image side. Figure 4 The image shows the on-axis beam Xa and off-axis beam Xb passing through lens Lx. Figure 4 In the example, ray Xb1, which is the upper ray of the off-axis beam Xb, is the ray that passes through the outermost edge. Therefore, in Figure 4 In the example, twice the distance from the point where the object-side surface of lens Lx intersects with ray Xb1 to the optical axis Z is the effective diameter ED of the object-side surface of lens Lx. Additionally, in Figure 4 In the optical system, the upper ray of the off-axis beam Xb is the ray that passes through the outermost edge, but which ray is the outermost ray depends on the optical system.

[0112] With the back focal length of the entire system at the air-converted distance of the wide-angle end when focusing on an object at infinity set to Bfw, the focal length of the entire system at the wide-angle end when focusing on an object at infinity set to fw, the maximum half angle of view at the wide-angle end when focusing on an object at infinity set to ωw, and the sum of the distance on the optical axis from the lens surface closest to the object side of the first lens group G1 at the wide-angle end to the lens surface closest to the image side of the final lens group GE at the wide-angle end and Bfw set to TLw, the zoom lens preferably satisfies the following condition (4). By ensuring that the corresponding value of condition (4) is not below the lower limit, it is easy to provide a zoom lens with high optical performance. By ensuring that the corresponding value of condition (4) is not above the upper limit, it is easy to provide a small and lightweight camera system. To obtain better characteristics, the zoom lens more preferably satisfies the following condition (4-1), and even more preferably satisfies the following condition (4-2).

[0113] 2.5<TLw / (fw×tan|ωw|)<7 (4)

[0114] 2.75<TLw / (fw×tan|ωw|)<5.75 (4-1)

[0115] 3<TLw / (fw×tan|ωw|)<5 (4-2)

[0116] When the angle between the normal NL of the lens surface at the effective diameter end P and the optical axis Z is set as α, the rear portion GMr preferably includes one or more convex lens surfaces facing the air that satisfy the following condition (5). In condition (5), the unit of α is set to degrees. As an example, Figure 5 The image side of lens L32 is shown as a dashed line, representing the normal NL of the surface at the effective diameter end P. The angle α between the normal NL and the optical axis Z is also shown. Figure 5The diagrams of some symbols are omitted. The effective diameter end P is the intersection point of the light ray passing from the outermost side and the lens surface in the definition of the effective diameter above. By ensuring that the corresponding value of condition (5) is not below the lower limit, the refractive power acting on the off-axis beam will not become too weak, thus suppressing the increase in the incident angle when the off-axis principal ray is incident on the image plane Sim. This is beneficial to ensuring the amount of peripheral light. By ensuring that the corresponding value of condition (5) is not above the upper limit, the increase in the processing difficulty of the above-mentioned convex surface can be suppressed, thus ensuring the surface accuracy. In order to obtain better characteristics, instead of condition (5), it is more preferable to satisfy the following condition (5-1), and even more preferable to satisfy the following condition (5-2).

[0117] 13<|α|<50 (5)

[0118] 15 < |α| < 40 (5-1)

[0119] 17<|α|<30 (5-2)

[0120] Preferably, an aperture diaphragm St is disposed on the object-side of the intermediate group GM or inside the intermediate group GM. Furthermore, the structure of "distributing an aperture diaphragm St inside the intermediate group GM" is as follows: in the intermediate group GM, one or more lenses are disposed on both the object-side and image-side of the aperture diaphragm St. When the aperture diaphragm St is disposed on the object-side of the intermediate group GM, it is possible to suppress the increase in the incident angle of off-axis principal rays when they are incident on the image plane Sim, thus helping to ensure peripheral light quantity. Furthermore, it facilitates the miniaturization of the lens diameter of the first lens group G1. When the aperture diaphragm St is disposed inside the intermediate group GM, optical symmetry becomes better, thus helping to suppress distortion aberrations and image plane curvature.

[0121] In a structure in which an aperture diaphragm St is arranged on the object-side of the intermediate group GM or inside the intermediate group GM, the rear part group GMR preferably includes one or more air-facing convex lens surfaces that satisfy condition (5) and condition (6) below. In condition (6), the distance on the optical axis from the aperture diaphragm St at the wide-angle end when focusing on an object at infinity to the aforementioned convex lens surface is set as DStw, and the focal length of the rear part group GMR at the wide-angle end when focusing on an object at infinity is set as fMrw. By ensuring that the corresponding value of condition (6) is not below the lower limit, the separation between the on-axis beam and the off-axis beam on the aforementioned convex lens surface will not become too small, thus helping to suppress image plane curvature. By ensuring that the corresponding value of condition (6) is not above the upper limit, it is beneficial to miniaturize the optical system. To obtain better characteristics, instead of condition (6), it is more preferable to satisfy condition (6-1), and even more preferable to satisfy condition (6-2).

[0122] 0.05 < DStw / |fMrw| < 2.5 (6)

[0123] 0.35 < DStw / |fMrw| < 2 (6-1)

[0124] 0.5<DStw / |fMrw|<1.65 (6-2)

[0125] Regarding the on-axis edge ray wa1 and the principal ray wb1 at the maximum image height at the wide-angle end when focusing on an object at infinity, the zoom lens preferably satisfies the following condition (7). As an example, the notation used in condition (7) is shown in Figure 6 . Figure 6 The middle shows Figure 1 A magnified view of a portion of the middle group GM at the wide-angle end of a zoom lens and the beam. HMfb is the height of the principal ray with the maximum image height on the image-side lens surface of the front part group GMf at the wide-angle end when focused on an object at infinity, from the optical axis Z. HMfa is the height of the on-axis edge ray on the image-side lens surface of the front part group GMf at the wide-angle end when focused on an object at infinity, from the optical axis Z. HMrb is the height of the principal ray with the maximum image height on the image-side lens surface of the rear part group GMr at the wide-angle end when focused on an object at infinity, from the optical axis Z. HMra is the height of the on-axis edge ray on the image-side lens surface of the rear part group GMr at the wide-angle end when focused on an object at infinity, from the optical axis Z. By ensuring that the corresponding value of condition (7) does not fall below the lower limit, the height of the off-axis beam in the rear part group GMr from the optical axis Z will not become too high, thus suppressing the amount of refraction in the final group GE. This is beneficial for correcting distortion aberrations. By ensuring that the corresponding value of condition (7) does not exceed the upper limit, the separation between the on-axis beam and the off-axis beam in the rear group GMR will not become too small, thus facilitating the correction of various aberrations of the off-axis beam. To obtain better characteristics, the zoom lens more preferably satisfies the following condition (7-1), and even more preferably satisfies the following condition (7-2).

[0126] 0.08<(HMfb / HMfa) / (HMrb / HMra)<0.8 (7)

[0127] 0.1<(HMfb / HMfa) / (HMrb / HMra)<0.6 (7-1)

[0128] 0.12<(HMfb / HMfa) / (HMrb / HMra)<0.52 (7-2)

[0129] When the paraxial radius of curvature of the lens surface closest to the object in the front group GMf is set to RMff, and the paraxial radius of curvature of the lens surface closest to the image in the front group GMf is set to RMfr, the zoom lens preferably satisfies the following condition (8). By ensuring that the corresponding value of condition (8) is not below the lower limit, it is beneficial to suppress insufficient correction of image plane curvature. By ensuring that the corresponding value of condition (8) is not above the upper limit, it is beneficial to suppress over-correction of image plane curvature. To obtain better characteristics, the zoom lens more preferably satisfies the following condition (8-1), and even more preferably satisfies the following condition (8-2).

[0130] -1<(RMff+RMfr) / (RMff-RMfr)<1 (8)

[0131] -0.5<(RMff+RMfr) / (RMff-RMfr)<0.3 (8-1)

[0132] -0.3<(RMff+RMfr) / (RMff-RMfr)<0.15 (8-2)

[0133] When the focal length of the entire system at the wide-angle end, focused on an object at infinity, is set to fw, and the focal length of the intermediate group GM at the wide-angle end, focused on an object at infinity, is set to fMw, the zoom lens preferably satisfies the following conditional expression (13). By ensuring that the corresponding value of conditional expression (13) is not below the lower limit, the movement of the intermediate group GM during zooming will not become excessive, thus facilitating a reduction in the overall length. By ensuring that the corresponding value of conditional expression (13) is not above the upper limit, it is beneficial to suppress aberration variations during zooming. To obtain even better characteristics, the zoom lens more preferably satisfies the following conditional expression (13-1), and even more preferably satisfies the following conditional expression (13-2).

[0134] 0.4 < fw / fMw < 1.5 (13)

[0135] 0.5 < fw / fMw < 1.35 (13-1)

[0136] 0.6 < fw / fMw < 1.2 (13-2)

[0137] When the focal length of the entire system at the wide-angle end is set to fw and the focal length of the focusing group is set to ffoc, the zoom lens preferably satisfies the following condition (14). By ensuring that the corresponding value of condition (14) is not below the lower limit, the amount of movement of the focusing group during focusing will not become too large, thus facilitating the miniaturization of the focusing unit. By ensuring that the corresponding value of condition (14) is not above the upper limit, the strictness of the positional accuracy of the focusing group during focusing can be suppressed, thus making it easy to control. To obtain better characteristics, the zoom lens more preferably satisfies the following condition (14-1), and even more preferably satisfies the following condition (14-2).

[0138] 0.05 < fw / |ffoc| < 2.5 (14)

[0139] 0.08 < fw / |ffoc| < 2 (14-1)

[0140] 0.12 < fw / |ffoc| < 1.5 (14-2)

[0141] When the average weight of all lenses included in the intermediate group GM is set to GMave, the zoom lens preferably satisfies the following conditional expression (15). By ensuring that the corresponding value of conditional expression (15) is not below the lower limit, the range of materials that can be used in the intermediate group GM can be expanded, which is beneficial for correcting axial chromatic aberration. By ensuring that the corresponding value of conditional expression (15) is not above the upper limit, the intermediate group GM will not become too heavy, which can suppress the enlargement of the mechanism driving the lens during zooming and / or focusing. To obtain better characteristics, the zoom lens more preferably satisfies the following conditional expression (15-1), and even more preferably satisfies the following conditional expression (15-2).

[0142] 3 < GMave < 4.2 (15)

[0143] 3.1 < GMave < 4 (15-1)

[0144] 3.2 < GMave < 3.85 (15-2)

[0145] When the partial dispersion ratio between the g-line and F-line of the positive lens in the intermediate group GM is set to θMp, and the dispersion coefficient of the d-line reference is set to νMp, the zoom lens preferably satisfies the following conditional expression (18). By ensuring that the corresponding value of conditional expression (18) is not below the lower limit, it is beneficial to suppress the undercorrection of the secondary spectrum of on-axis chromatic aberration. By ensuring that the corresponding value of conditional expression (18) is not above the upper limit, it is beneficial to suppress the overcorrection of the secondary spectrum of on-axis chromatic aberration. To obtain better characteristics, the zoom lens more preferably satisfies the following conditional expression (18-1), and even more preferably satisfies the following conditional expression (18-2).

[0146] 0.01<θMp+0.0018×vMp-0.64833<0.06 (18)

[0147] 0.017<θMp+0.0018×vMp-0.64833<0.05 (18-1)

[0148] 0.022<θMp+0.0018×vMp-0.64833<0.04 (18-2)

[0149] When the focal length of the front portion GMf at the wide-angle end, focused on an object at infinity, is set to fMfw, and the focal length of the rear portion GMr at the wide-angle end, focused on an object at infinity, is set to fMrw, the zoom lens preferably satisfies the following condition (26). By ensuring that the corresponding value of condition (26) is not below the lower limit, the refractive power of the rear portion GMr will not become too weak, thus facilitating the correction of image plane curvature. By ensuring that the corresponding value of condition (26) is not above the upper limit, the refractive power of the front portion GMf will not become too weak, thus facilitating the correction of spherical aberration. To obtain even better characteristics, the zoom lens more preferably satisfies the following condition (26-1), and even more preferably satisfies the following condition (26-2).

[0150] 0.25<fMfw / |fMrw|<2 (26)

[0151] 0.3<fMfw / |fMrw|<1.75 (26-1)

[0152] 0.35<fMfw / |fMrw|<1.5 (26-2)

[0153] When the sum of the air gaps on the optical axis between the object-side lens surface of the rear part group GMR at the wide-angle end when focusing on an object at infinity and the image-side lens surface of the rear part group GMR is set to DMra, and the distance on the optical axis from the object-side lens surface of the rear part group GMR at the wide-angle end to the image-side lens surface of the rear part group GMR when focusing on an object at infinity is set to DMrt, the zoom lens preferably satisfies the following condition (21). By ensuring that the corresponding value of condition (21) is not below the lower limit, the increase in weight of the rear part group GMR can be suppressed, which is beneficial for the weight reduction of the drive mechanism. By ensuring that the corresponding value of condition (21) is not above the upper limit, the aberration correction effect of the rear part group GMR can be ensured, which is beneficial for suppressing aberration changes during zoom. To obtain better characteristics, the zoom lens more preferably satisfies the following condition (21-1), and more preferably satisfies the following condition (21-2).

[0154] 0.2 < DMra / DMrt < 0.95 (21)

[0155] 0.35<DMra / DMrt<0.92 (21-1)

[0156] 0.6 < DMra / DMrt < 0.9 (21-2)

[0157] Preferably, the rear-side portion of the GMr includes an image-side negative lens with a convex image-side surface. This is advantageous for suppressing image plane curvature. Furthermore, it is preferable that the rear-side portion of the GMr includes an object-side negative lens with a convex object-side surface, located further from the object side than the image-side negative lens. This is advantageous for suppressing spherical aberration. Figure 1 In the example, the object-side negative lens corresponds to lens L31, and the image-side negative lens corresponds to lens L32.

[0158] When the paraxial radius of curvature of the image-side surface of the object-side negative lens is set to Rnor, and the paraxial radius of curvature of the object-side surface of the image-side negative lens is set to Rnif, the rear-side group GMR preferably includes a group of object-side negative lenses and image-side negative lenses that satisfy the following condition (22). By ensuring that the corresponding value of condition (22) is not below the lower limit, it is beneficial to suppress spherical aberration. By ensuring that the corresponding value of condition (22) is not above the upper limit, it is beneficial to suppress image plane curvature. In order to obtain better characteristics, instead of condition (22), it is more preferable to satisfy the following condition (22-1), and even more preferable to satisfy the following condition (22-2).

[0159] -1.5<(Rnor+Rnif) / (Rnor-Rnif)<1 (22)

[0160] -1.2<(Rnor+Rnif) / (Rnor-Rnif)<0.5 (22-1)

[0161] -0.8<(Rnor+Rnif) / (Rnor-Rnif)<0.25 (22-2)

[0162] When the focal length of the entire system at the wide-angle end, focused on an object at infinity, is set to fw, and the focal length of the rear portion group GMR at the wide-angle end, focused on an object at infinity, is set to fMrw, the zoom lens preferably satisfies the following condition (25). By ensuring that the corresponding value of condition (25) is not below the lower limit, the refractive power of the rear portion group GMR will not become too weak, thus facilitating the correction of image plane curvature. By ensuring that the corresponding value of condition (25) is not above the upper limit, the refractive power of the rear portion group GMR will not become too strong, thus facilitating the miniaturization of the final group GE. To obtain better characteristics, the zoom lens more preferably satisfies the following condition (25-1), and even more preferably satisfies the following condition (25-2).

[0163] 0.15 < fw / |fMrw| < 2 (25)

[0164] 0.22<fw / |fMrw|<1.75 (25-1)

[0165] 0.28 < fw / |fMrw| < 1.5 (25-2)

[0166] The temperature coefficient of the relative refractive index with respect to the d-line within the range of 20°C to 40°C for the positive lenses included in the intermediate group GM is set as (dNMp / dT)×10. -6 Set the unit of dNMp / dT to K (Kelvin). -1 In this case, the intermediate group GM preferably includes one or more positive lenses that satisfy the following condition (29). Generally, there are more materials with positive temperature coefficients, so by including positive lenses in the intermediate group GM within the range of condition (29), it is beneficial to suppress performance changes when the temperature changes. In order to obtain better characteristics, instead of condition (29), it is more preferable to satisfy the following condition (29-1), and even more preferably to satisfy the following condition (29-2).

[0167] -15<dNMp / dT<0 (29)

[0168] -10 < dNMp / dT < -3 (29-1)

[0169] -7<dNMp / dT<-5 (29-2)

[0170] Preferably, the intermediate group GM has positive refractive power. In this case, the zoom ratio can be easily increased by using the first lens group G1 with negative refractive power and the intermediate group GM with positive refractive power, and it is also beneficial to correct spherical aberration. Furthermore, by using the intermediate group GM with positive refractive power, the final group GE immediately following the intermediate group GM can be miniaturized, thus also facilitating overall miniaturization.

[0171] The intermediate group GM can be configured to include a front portion group GMf and a rear portion group GMr. In this case, compared to the case that includes groups other than the front portion group GMf and the rear portion group GMr, it is advantageous for miniaturization and weight reduction. However, the intermediate group GM can also be configured to include a front portion group GMf, a rear portion group GMr, and other groups. In this case, it is advantageous to ensure higher optical performance.

[0172] Preferably, the lens closest to the object side of the front group GMf is a positive lens. In this case, it is beneficial to minimize the diameter of the middle group GM. Preferably, the lens closest to the image side of the front group GMf is a positive lens. In this case, it is beneficial to minimize the diameter of the rear group GMr.

[0173] Preferably, the rear portion of the GMr assembly includes two or more lenses. In this case, it is beneficial to suppress performance changes during zooming.

[0174] The lens closest to the image side of the rear group GMr can be configured as a negative lens. In this case, the height of the off-axis rays incident on the final group GE can be increased, thus suppressing the increase in the incident angle of the off-axis principal rays when they incident on the imaging element located on the image plane Sim. This helps to ensure the amount of peripheral light.

[0175] For example, the rear-side portion GMr can be configured to include two negative lenses. More specifically, the rear-side portion GMr can be configured to include two negative meniscus lenses arranged concave to convex. Furthermore, a "negative meniscus lens" is a meniscus lens with negative refractive power. Alternatively, the rear-side portion GMr can be configured to include two negative lenses and one positive lens. The rear-side portion GMr can also be configured to include a combined lens consisting of one negative lens and one positive lens, and a negative lens. The rear-side portion GMr can also be configured to include a biconvex air lens.

[0176] It can be configured such that a biconcave air lens is formed between the front part group GMf and the rear part group GMR. In this case, it is advantageous to reduce the diameter of the rear part group GMR. Figure 1 In the example, the image-side surface of lens L24 and the object-side surface of lens L31 form a biconcave air lens.

[0177] It can be configured such that the spacing between the front portion group GMf and the rear portion group GMR changes during zooming. In this case, it is beneficial to suppress performance changes during zooming. When the intermediate group GM includes multiple lens groups that move by changing the spacing in the optical axis direction between themselves and adjacent groups during zooming, it can be configured to separate the front portion group GMf and the rear portion group GMR using any of the spacings that change during zooming. For example, it can be configured to separate the front portion group GMf and the rear portion group GMR using the spacing closest to the object side among the spacings that change during zooming in the intermediate group GM. Alternatively, it can be configured to separate the front portion group GMf and the rear portion group GMR using the spacing closest to the image side among the spacings that change during zooming in the intermediate group GM.

[0178] In a case where the intermediate group GM includes a lens group that moves by changing the spacing in the optical axis direction between itself and adjacent groups during zooming, and the focusing group only includes a portion of the intermediate group GM, it can be configured such that the portion of the intermediate group GM that is closer to the object side than the focusing group is designated as the front portion group GMf, and the portion of the intermediate group GM that is closer to the image side than the front portion group GMf is designated as the rear portion group GMr. In this case, the front portion group GMf has positive refractive power, which is beneficial for miniaturizing the focusing group.

[0179] The focusing unit can be configured such that, during focusing, at least a portion of the front-side group GMf moves along the optical axis Z, while other groups remain fixed relative to the image plane Sim. This facilitates miniaturization of the focusing unit when the focusing group is composed of lenses from the relatively small effective diameter front-side group GMf. The focusing group can be configured to include only a portion of the front-side group GMf, or it can include the entire front-side group GMf. For example, if the front-side group GMf includes multiple lens groups that move by changing the spacing in the optical axis direction between adjacent groups during zooming, the focusing group can be composed only of the lens group closest to the object side among these multiple lens groups. Furthermore, if an aperture st is disposed inside the front-side group GMf, the focusing group can be composed only of the portion of the front-side group GMf that is closer to the object side than the aperture st. Additionally, "an aperture st is disposed inside the front-side group GMf" means that in the front-side group GMf, one or more lenses are disposed on both the object side and the image side of the aperture st.

[0180] The focusing group can be configured such that, during focusing, at least a portion of the rear-side group GMR moves along the optical axis Z, while the other groups remain fixed relative to the image plane Sim. In this configuration, it is advantageous to suppress variations in spherical aberration that occur with changes in shooting distance. The focusing group can be configured to include only a portion of the rear-side group GMR, or it can be configured to include the entire rear-side group GMR. Furthermore, when the focusing group includes only the lens closest to the object side of the rear-side group GMR, it also offers the advantage of miniaturization of the focusing unit.

[0181] Furthermore, all lenses that move during focusing can move along the same trajectory. That is, the movement trajectory of the focusing group included in the zoom lens can be configured as one. By simplifying the focusing group in this way, it is beneficial to miniaturize and lighten the focusing unit.

[0182] Preferably, the first lens group G1 is a negative meniscus lens with a convex surface on the object-side closest to it. By arranging a negative lens on the object-side closest to it, the incident pupil can be brought closer to the object side, thus helping to ensure the viewing angle at the wide-angle end and reduce the aperture size. Furthermore, by making the lens on the object-side closest to it meniscus, it is beneficial to suppress astigmatism and distortion aberrations.

[0183] In the structure of the first lens group G1, which is a negative meniscus lens with a convex surface on the object side, the zoom lens preferably satisfies the following condition (10) when the paraxial radius of curvature of the object side surface of the negative meniscus lens is set to R1f and the paraxial radius of curvature of the image side surface is set to R1r. By ensuring that the corresponding value of condition (10) is not below the lower limit, it is beneficial to suppress astigmatism from the wide-angle end to the telephoto end. By ensuring that the corresponding value of condition (10) is not above the upper limit, it is beneficial to suppress distortion aberrations and image plane curvature at the wide-angle end. To obtain better characteristics, the zoom lens more preferably satisfies the following condition (10-1), and even more preferably satisfies the following condition (10-2).

[0184] 1<(R1f+R1r) / (R1f-R1r)<6 (10)

[0185] 1.5<(R1f+R1r) / (R1f-R1r)<4.3 (10-1)

[0186] 2.2<(R1f+R1r) / (R1f-R1r)<3.2 (10-2)

[0187] Preferably, the first lens group G1 includes two or more negative meniscus lenses with convex surfaces on the object side. In this case, multiple lenses can share the negative refractive power, thus making it easier to increase the absolute value of the radius of curvature of the image-side surface of each negative meniscus lens. This is beneficial for suppressing astigmatism on the wide-angle side.

[0188] When the refractive index of the positive lens included in the first lens group G1 relative to the d-line is set to N1p, the first lens group G1 preferably includes one or more positive lenses that satisfy the following condition (11). By ensuring that the corresponding value of condition (11) is not below the lower limit, the absolute value of the radius of curvature of the positive lens in the first lens group G1 will not become too small, thus which is beneficial for suppressing astigmatism. By ensuring that the corresponding value of condition (11) is not above the upper limit, the absolute value of the radius of curvature of the positive lens in the first lens group G1 will not become too large, thus which is beneficial for correcting image plane curvature. In order to obtain better characteristics, instead of condition (11), it is more preferable to satisfy the following condition (11-1), and even more preferable to satisfy the following condition (11-2).

[0189] 1.6 < N1p < 2.15 (11)

[0190] 1.75 < N1p < 2.07 (11-1)

[0191] 1.83 < N1p < 2.02 (11-2)

[0192] When the focal length of the entire system at the wide-angle end, with the focus on an object at infinity, is set to fw, and the focal length of the first lens group G1 is set to f1, the zoom lens preferably satisfies the following condition (12). By ensuring that the corresponding value of condition (12) is not below the lower limit, the variation in the interval between the first lens group G1 and the group closest to the object within the intermediate group GM will not become too large, thus facilitating a shorter overall length. By ensuring that the corresponding value of condition (12) is not above the upper limit, the diameter of the beam incident on the intermediate group GM will not become too large, thus facilitating the miniaturization of the lens system as a whole. To obtain even better characteristics, the zoom lens more preferably satisfies the following condition (12-1), and even more preferably satisfies the following condition (12-2).

[0193] 0.3 < fw / |f1| < 1.5 (12)

[0194] 0.45 < fw / |f1| < 1.25 (12-1)

[0195] 0.6 < fw / |f1| < 1.1 (12-2)

[0196] The temperature coefficient of the relative refractive index with respect to the d-line within the temperature range of 20°C to 40°C for the negative lenses included in the first lens group G1 is set as (dN1n / dT)×10. -6 Set the unit of dN1n / dT to K (Kelvin). -1In this case, the first lens group G1 preferably includes one or more negative lenses that satisfy the following condition (16). Generally, there are more materials with positive temperature coefficients, so by including negative lenses in the first lens group G1 within the range of condition (16), it is beneficial to suppress performance changes when the temperature changes. In order to obtain better characteristics, instead of condition (16), it is more preferable to satisfy the following condition (16-1), and even more preferably to satisfy the following condition (16-2).

[0197] -15<dN1n / dT<0 (16)

[0198] -10<dN1n / dT<-3 (16-1)

[0199] -7<dN1n / dT<-5 (16-2)

[0200] A portion of the first lens group G1 can be configured to move in a direction intersecting the optical axis Z when correcting image jitter as an anti-shake group. In this specification, the group that moves when correcting image jitter is referred to as the "anti-shake group." Image jitter correction is performed by moving the anti-shake group. By constructing the anti-shake group from only a portion of the first lens group G1, the first lens group G1 as a whole and the anti-shake group can have different refractive powers, thus making it easier to control the refractive power of the anti-shake group and facilitating both good anti-shake performance and miniaturization. For example, the anti-shake group can be configured as a single lens including the image-side of the first lens group G1. In this case, miniaturization of the anti-shake group is advantageous.

[0201] In a zoom lens with an anti-shake assembly, when the focal length of the entire system at the wide-angle end is set to fw and the focal length of the anti-shake assembly is set to fis, the zoom lens preferably satisfies the following condition (17). By ensuring that the corresponding value of condition (17) is not below the lower limit, the movement of the anti-shake assembly during image shake correction will not become excessive, thus facilitating the miniaturization of the anti-shake unit. By ensuring that the corresponding value of condition (17) is not above the upper limit, it is beneficial to suppress aberration variations during image shake correction. By satisfying condition (17), it is beneficial to achieve good image shake correction performance while realizing the miniaturization of the anti-shake unit. To obtain even better characteristics, the zoom lens more preferably satisfies the following condition (17-1), and even more preferably satisfies the following condition (17-2).

[0202] 0.05 < fw / |fis| < 0.75 (17)

[0203] 0.1 < fw / |fis| < 0.5 (17-1)

[0204] 0.15 < fw / |fis| < 0.25 (17-2)

[0205] When the refractive index of the negative lens closest to the object in the first lens group G1 relative to the d-line is set to N1n, the zoom lens preferably satisfies the following condition (20). By ensuring that the corresponding value of condition (20) is not below the lower limit, the absolute value of the radius of curvature of the negative lens will not become too small, thus helping to suppress off-axis aberrations from the wide-angle end to the telephoto end. By ensuring that the corresponding value of condition (20) is not above the upper limit, it is easy to suppress the negative lens from becoming highly dispersed and having a high specific gravity, thus helping to correct chromatic aberration at the wide-angle end and reduce weight. To obtain better characteristics, the zoom lens more preferably satisfies the following condition (20-1), and even more preferably satisfies the following condition (20-2).

[0206] 1.6 < N1n < 2.15 (20)

[0207] 1.65 < N1n < 2.07 (20-1)

[0208] 1.7 < N1n < 2 (20-2)

[0209] When the average weight of all lenses included in the first lens group G1 is set to Glave, the zoom lens preferably satisfies the following conditional expression (23). By ensuring that the corresponding value of conditional expression (23) is not below the lower limit, the range of materials that can be used in the first lens group G1 can be expanded, which is beneficial for correcting chromatic aberration. By ensuring that the corresponding value of conditional expression (23) is not above the upper limit, the first lens group G1 will not become too heavy, which can suppress the center of gravity of the entire optical system from shifting towards the object side. This helps to reduce the burden on the user when holding the zoom lens. To obtain better characteristics, the zoom lens more preferably satisfies the following conditional expression (23-1), and even more preferably satisfies the following conditional expression (23-2).

[0210] 3 < G1ave < 4.5 (23)

[0211] 3.15 < Glave < 4.3 (23-1)

[0212] 3.2 < G1ave < 4.2 (23-2)

[0213] like Figure 1 As in the example, the first lens group G1 can be configured to move along the optical axis Z by changing the interval between it and the intermediate group GM during zooming. In this case, it is beneficial to suppress aberration variations during zooming. Alternatively, it can be configured such that the first lens group G1 is fixed relative to the image plane Sim during zooming. In this case, a movable mechanism for the first lens group G1 is not required, thereby simplifying the mechanical structure and thus facilitating miniaturization and weight reduction.

[0214] The first lens group G1 preferably includes three or more but no more than six lenses. In this case, it is beneficial for miniaturization and weight reduction, as well as for suppressing variations in aberrations during zooming. The first lens group G1 is more preferably three or more but no more than five lenses, and even more preferably four or more but no more than five lenses.

[0215] The first lens group G1 can be configured as a joint lens consisting of a negative lens and a positive lens. In this case, it is advantageous for correcting chromatic aberration. One of the joint lenses included in the first lens group G1 can be formed by sequentially joining a negative lens and a positive lens from the object side. Furthermore, the joint surface of the joint lens included in the first lens group G1 can be configured with a convex surface facing the object side.

[0216] The first lens group G1 can be configured to include three negative lenses and one positive lens. In this case, the first lens group G1 can be configured to include, from the object side to the image side, two negative lenses (single lenses) and a combined lens formed by sequentially joining the negative and positive lenses from the object side. Alternatively, the first lens group G1 can be configured to include, from the object side to the image side, one negative lens, a combined lens formed by sequentially joining the negative and positive lenses from the object side, and one negative lens.

[0217] The first lens group G1 can be configured to include four negative lenses and one positive lens. In this case, for example, the first lens group G1 can be configured to include, from the object side to the image side, two negative lenses (single lenses), a combined lens formed by sequentially joining the negative and positive lenses from the object side, and one negative lens (single lens).

[0218] When the focal length of the entire system at the wide-angle end is set to fw when focusing on an object at infinity, and the focal length of the final group GE at the wide-angle end is set to fE, the zoom lens preferably satisfies the following condition (27). By ensuring that the corresponding value of condition (27) is not below the lower limit, it is particularly beneficial to suppress the increase in the incident angle when the off-axis principal ray is incident on the image plane Sim at the wide-angle end. By ensuring that the corresponding value of condition (27) is not above the upper limit, it is easy to suppress image plane curvature. To obtain better characteristics, the zoom lens more preferably satisfies the following condition (27-1), and even more preferably satisfies the following condition (27-2).

[0219] 0.01 < fw / fE < 0.75 (27)

[0220] 0.03 < fw / fE < 0.6 (27-1)

[0221] 0.15 < fw / fE < 0.52 (27-2)

[0222] When the average weight of all lenses included in the final group GE is set to GEave, the zoom lens preferably satisfies the following conditional expression (24). By ensuring that the corresponding value of conditional expression (24) is not below the lower limit, the final group GE will not become too light, thus suppressing the center of gravity of the entire optical system from shifting towards the object side. This helps to reduce the burden on the user when holding the zoom lens. By ensuring that the corresponding value of conditional expression (24) is not above the upper limit, the final group GE will not become too heavy, thus contributing to the overall lightweighting of the lens system. To obtain better characteristics, the zoom lens more preferably satisfies the following conditional expression (24-1), and even more preferably satisfies the following conditional expression (24-2).

[0223] 2.5 < GEave < 5 (24)

[0224] 3 < GEave < 4 (24-1)

[0225] 3.2 < GEave < 3.7 (24-2)

[0226] Preferably, the final GE group has positive refractive power. In this case, it is possible to suppress the increase in the incident angle when the off-axis principal ray is incident on the image plane Sim, thus helping to ensure the amount of peripheral light.

[0227] Preferably, during zooming, the final group GE is fixed relative to the image plane Sim. By arranging the group that is fixed during zooming on the image side closest to the image, it is beneficial to suppress changes in magnification chromatic aberration during zooming.

[0228] The final GE group can be configured to include two or fewer lenses. In this case, miniaturization and weight reduction are advantageous. When the final GE group includes a combined lens consisting of a positive lens and a negative lens, it is advantageous for correcting chromatic aberration. Alternatively, the final GE group can be configured to include only one lens. In this case, miniaturization and weight reduction are even more advantageous.

[0229] When the distance from the image plane Sim at the wide-angle end to the exit pupil position is set to Pexpw when focusing on an object at infinity, and the focal length of the entire system at the wide-angle end when focusing on an object at infinity is set to fw, the zoom lens preferably satisfies the following condition (9). By ensuring that the corresponding value of condition (9) is not below the lower limit, the angle of incidence when the off-axis principal ray is incident on the image plane Sim will not become too large, thus ensuring the amount of peripheral light. By ensuring that the corresponding value of condition (9) is not above the upper limit, it is beneficial to miniaturize the lens system. To obtain better characteristics, the zoom lens more preferably satisfies the following condition (9-1), and even more preferably satisfies the following condition (9-2).

[0230] 0.5 < Pexpw / fw < 5 (9)

[0231] 1 < Pexpw / fw < 4.2 (9-1)

[0232] 1.4 < Pexpw / fw < 3.7 (9-2)

[0233] When the distance on the optical axis from the object-side lens surface of the first lens group G1 at the telephoto end to the image-side lens surface of the final group GE at the telephoto end, and the sum of the back focal length of the entire system at the telephoto end in terms of the air equivalent distance when focusing on an object at infinity, is set as TLt, the focal length of the entire system at the telephoto end when focusing on an object at infinity is set as ft, and the maximum half angle of view at the telephoto end when focusing on an object at infinity is set as ωt, the zoom lens preferably satisfies the following condition (19). Figure 2 An example of ωt is shown. By ensuring that the corresponding value of condition (19) is not below the lower limit, it is easy to provide a zoom lens with high optical performance. By ensuring that the corresponding value of condition (19) is not above the upper limit, it is easy to provide a small and lightweight camera system. To obtain better characteristics, the zoom lens more preferably satisfies the following condition (19-1), and even more preferably satisfies the following condition (19-2).

[0234] 2.85<TLt / (ft×tan|ωt|)<7 (19)

[0235] 3.2<TLt / (ft×tan|ωt|)<6 (19-1)

[0236] 3.5<TLt / (ft×tan|ωt|)<5.25 (19-2)

[0237] When the focal length of the entire system at the wide-angle end with the object focused at infinity is set to fw, and the focal length of the entire system at the telephoto end with the object focused at infinity is set to ft, the zoom lens preferably satisfies the following conditional expression (28). By ensuring that the corresponding value of conditional expression (28) is not below the lower limit, a zoom ratio that is meaningful for the zoom lens can be ensured. By ensuring that the corresponding value of conditional expression (28) is not above the upper limit, miniaturization is beneficial. To obtain better characteristics, the zoom lens more preferably satisfies the following conditional expression (28-1), and even more preferably satisfies the following conditional expression (28-2).

[0238] 1.3 < ft / fw < 5 (28)

[0239] 1.4 < ft / fw < 3 (28-1)

[0240] 1.45 < ft / fw < 2.5 (28-2)

[0241] When the maximum half-angle of the wide-angle end is set to ωw when focusing on an object at infinity, and the unit of ωw is degrees, the zoom lens preferably satisfies the following condition (30). By ensuring that the corresponding value of condition (30) is not below the lower limit, the angle of view will not become too narrow, thus facilitating a reduction in the overall length of the lens system in which the first lens group G1 closest to the object has negative refractive power. By ensuring that the corresponding value of condition (30) is not above the upper limit, the angle of view will not become too wide, thus making it easier to miniaturize the first lens group G1 and suppressing the overall enlargement of the lens system. To obtain even better characteristics, the zoom lens more preferably satisfies the following condition (30-1), and even more preferably satisfies the following condition (30-2).

[0242] 28<ωw<90 (30)

[0243] 32<ωw<65 (30-1)

[0244] 35<ωw<60 (30-2)

[0245] Including the structures related to the conditional expressions, the above-mentioned preferred structures and implementable structures can be combined arbitrarily, and are preferably selected appropriately according to the required specifications. In addition, the conditional expressions preferably satisfied by the zoom lens of the present invention are not limited to the conditional expressions described in the form of formulas, but also include all conditional expressions obtained by arbitrarily combining the lower limit and the upper limit from the preferred, more preferred and further preferred conditional expressions.

[0246] As an example, a preferred embodiment of the zoom lens of the present invention is a zoom lens comprising, from the object side to the image side, a first lens group G1 having negative refractive power, an intermediate group GM, and a final group GE. During zooming, the interval between the first lens group G1 and the intermediate group GM changes, and the interval between the intermediate group GM and the final group GE changes. During focusing, at least a portion of the intermediate group GM moves along the optical axis Z as a focusing group. The first lens group G1 and the final group GE are fixed relative to the image plane Sim, and the above-described conditional expression (1) is satisfied. According to this preferred embodiment, a small and lightweight zoom lens with a large image circle and high optical performance can be provided.

[0247] Next, embodiments of the zoom lens of the present invention will be described with reference to the accompanying drawings. Furthermore, reference numerals for the lens, as indicated in the cross-sectional views of each embodiment, are used independently for each embodiment to avoid increasing the number of reference numerals and complicating the description and drawings. Therefore, even if the same reference numerals are used in the drawings of different embodiments, they do not necessarily represent the same structure.

[0248] [Example 1]

[0249] A cross-sectional view of the structure of the zoom lens in Example 1 is shown in Figure 1 The illustrated method and structure are as described above, therefore some repetitive descriptions are omitted here. The zoom lens of Embodiment 1, along the optical axis Z from the object side to the image side, sequentially includes a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, a third lens group G3 with negative refractive power, and a fourth lens group G4 with positive refractive power. The intermediate group GM includes the second lens group G2 and the third lens group G3. The front part group GMf includes the second lens group G2. The rear part group GMr includes the third lens group G3. The final group GE includes the fourth lens group G4.

[0250] During zooming, the first lens group G1, the second lens group G2, and the third lens group G3 change their spacing along the optical axis Z with respect to adjacent groups, while the fourth lens group G4 remains fixed relative to the image plane Sim. The focusing group includes the entire third lens group G3.

[0251] Regarding the zoom lens of Example 1, basic lens data is shown in Table 1, specifications and variable surface spacing are shown in Table 2, and aspherical coefficients are shown in Table 3. Table 1 is described as follows: The Sn column shows the surface numbering with the surface closest to the object side as the first surface, increasing sequentially towards the image side. The R column shows the radius of curvature of each surface. The D column shows the surface spacing on the optical axis between each surface and its image-side adjacent surface. The Nd column shows the refractive index of each component relative to the d-line. The vd column shows the dispersion coefficient of each component based on the d-line. The θgF column shows the partial dispersion ratio between the g-line and F-line of each component. The SG column shows the specific gravity of each component. The dNd / dT column shows the temperature coefficient of the relative refractive index of each component relative to the d-line in the range of 20°C to 40°C, multiplied by 10⁶. The unit of the temperature coefficient is Kelvin. -1 The effective diameter is shown in the ED column. ED only shows the lens surface of the intermediate group GM on the object side and the lens surface of the intermediate group GM on the image side.

[0252] In Table 1, the radius of curvature of the convex surface facing the object side is marked positive, and the radius of curvature of the convex surface facing the image side is marked negative. Table 1 also shows the aperture St and optical components PP. The term (St) is recorded along with the surface number in the surface number column corresponding to the aperture St. The value in the bottom column of D in Table 1 is the interval between the surface closest to the image side and the image plane Sim. In Table 1, the variable surface interval is notated using DD[], with the object-side surface number of the interval marked in [] and recorded in column D.

[0253] Table 2 shows the zoom ratio Zr, focal length f, back focal length at air equivalent distance, open F-number FNo., maximum full angle of view 2ω, and variable plane spacing for each zoom and focus state. The approximate size of the image circle can be calculated from f and ω. The (°) in the 2ω column indicates the unit as degrees. In Table 2, the values ​​for the wide-angle, intermediate, and telephoto states are shown in the columns labeled "Wide-angle," "Intermediate," and "Telephoto," respectively. Furthermore, the values ​​for focusing on an object at infinity are shown in the column labeled "Infinity," and the values ​​for a magnification of -0.1 are shown in the column labeled "β = -0.1." Additionally, some values ​​are omitted in the column labeled "β = -0.1." The values ​​shown in Tables 1 and 2 are based on the d-line.

[0254] In the basic lens data, aspherical surfaces are marked with an asterisk (*), and the paraxial radius of curvature is recorded in the radius of curvature column. Table 3 shows the surface number of the aspherical surface in row Sn, and the aspheric coefficient values ​​for each aspherical surface in rows KA and Am. Furthermore, m in Am is an integer greater than or equal to 3 and varies from surface to surface. For example, on surface 11, m = 3, 4, 5, ..., 10. The aspheric coefficient values ​​in Table 3, "E±n" (n: integer), represent "×10". ±n KA and Am are the aspheric coefficients in the aspheric formula expressed by the following equation.

[0255] Zd=C×h 2 / {1+(1-KA×C 2 ×h 2 ) 1 / 2}+∑Am×h m

[0256] in,

[0257] Zd: Aspherical depth (the length of the perpendicular line from a point on the aspherical surface at height h to a plane tangent to the vertex of the aspherical surface and perpendicular to the optical axis Z);

[0258] h: Height (distance from the optical axis Z to the lens surface);

[0259] C: The reciprocal of the paraxial radius of curvature;

[0260] KA, Am: Aspheric coefficients

[0261] In aspherical form, ∑ represents the summation related to m.

[0262] In the data in each table, degrees are used as the unit for angles and millimeters as the unit for lengths. Optical systems can be used at both magnified and reduced scales, so other appropriate units may also be used. Furthermore, the values ​​are rounded to a specified number of decimal places in the tables shown below.

[0263] [Table 1]

[0264] Example 1

[0265] 1 69.10435 1.150 1.80518 25.46 0.61572 3.36 0.9 2 29.85137 2.352 3 52.09331 1.000 1.58313 59.46 0.54336 3.24 3.4 4 22.56329 7.149 5 ∞ 0.960 1.48749 70.39 0.53005 2.48 -1.5 6 22.93740 5.040 1.91083 35.26 0.58293 5.07 4.4 7 101.46452 DD[7] 8 (St) ∞ 0.800 9 18.96999 7.000 1.49700 81.61 0.53887 3.70 -7.5 16.58 10 -38.73407 3.487 *11 -14.21597 1.890 1.58313 59.46 0.54056 3.01 3.9 *12 -28.12065 1.500 13 -70.09062 0.860 1.51741 52.16 0.56212 2.52 -0.4 14 16.72780 6.170 1.49700 81.61 0.53887 3.70 -6.2 15 -16.72780 DD

[15] 16 36.63948 0.850 1.67790 55.56 0.54672 3.80 0.9 17 22.72340 12.500 18 -20.61508 0.850 1.64769 33.84 0.59227 2.73 0.8 19 -41.33431 DD

[19] 25.84 20 ∞ 6.040 1.58144 40.75 0.57841 2.61 2.3 21 -68.19290 19.092 22 ∞ 2.850 1.51680 64.20 0.53430 23 ∞ 1.122

[0266] [Table 2]

[0267] Example 1

[0268]

[0269] [Table 3]

[0270] Example 1

[0271] KA 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 A4 1.9333299E-04 2.0939860E-04 A5 -3.2634652E-06 -2.7452878E-06 A6 -1.3836702E-07 -1.1927223E-07 A7 3.1412740E-08 2.9002318E-08 A8 -1.7877300E-08 -1.1774910E-08 A9 1.6054978E-09 6.5535125E-10 A10 -2.4959670E-11 1.0444752E-11

[0272] Figure 7 The diagram shows the aberrations of the zoom lens of Embodiment 1 when focused on an object at infinity. Figure 7 In the image, from left to right, spherical aberration, astigmatism, distortion aberration, and magnification chromatic aberration are shown. Figure 7 In the diagram, the upper section marked "WIDE" shows aberrations at the wide-angle end, the middle section marked "MIDDLE" shows aberrations at the intermediate focal length, and the lower section marked "TELE" shows aberrations at the telephoto end. In the spherical aberration diagram, aberrations below the d-line, C-line, F-line, and g-line are shown with solid lines, long dashed lines, short dashed lines, and double-dotted lines, respectively. In the astigmatism diagram, aberrations below the d-line in the sagittal direction are shown with solid lines, and aberrations below the d-line in the meridional direction are shown with short dashed lines. In the distortion aberration diagram, aberrations below the d-line are shown with solid lines. In the chromatic aberration diagram, aberrations below the C-line, F-line, and g-line are shown with long dashed lines, short dashed lines, and double-dotted lines, respectively. In the spherical aberration diagram, the open F-value is shown after "FNo.=". In other aberration diagrams, the maximum half-angle value is shown after "ω=".

[0273] Unless otherwise specified, the notation, meaning, recording method and illustration method of the data related to Embodiment 1 above are the same in the following embodiments, so repeated descriptions are omitted below.

[0274] [Example 2]

[0275] Figure 8The diagram shows a cross-sectional view and movement trajectory of the wide-angle end structure of the zoom lens of Embodiment 2 when focused on an object at infinity. The zoom lens of Embodiment 2, along the optical axis Z from the object side to the image side, sequentially includes a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, a third lens group G3 with negative refractive power, and a fourth lens group G4 with positive refractive power. The intermediate group GM includes the second lens group G2 and the third lens group G3. The front portion group GMf includes the second lens group G2. The rear portion group GMr includes the third lens group G3. The final group GE includes the fourth lens group G4.

[0276] Lens group G1 consists of five lenses, L11 to L15, arranged sequentially from the object side to the image side. Lens group G2 consists of four lenses, L21 to L24, arranged sequentially from the object side to the image side. Lens group G3 consists of two lenses, L31 and L32, arranged sequentially from the object side to the image side. Lens group G4 consists of lens L41.

[0277] During zooming, lens groups G1, G2, and G3 change their spacing along the optical axis Z from adjacent groups, while lens group G4 remains fixed relative to the image plane Sim. The focusing group comprises the entire third lens group G3. The image stabilization group comprises lens L15. Figure 8 In the diagram, a double arrow pointing vertically is marked below the vibration damping assembly. The method of illustrating this vibration damping assembly is the same in the following embodiments.

[0278] Regarding the zoom lens of Example 2, the basic lens data is shown in Table 4, the specifications and variable surface spacing are shown in Table 5, the aspherical coefficients are shown in Table 6, and the various aberrations are illustrated in Table 7. Figure 9 .

[0279] [Table 4]

[0280] Example 2

[0281] 1 41.01322 1.850 1.74000 28.30 0.60790 3.11 2.4 2 24.32746 3.829 3 54.22078 1.500 1.58313 59.37 0.54345 3.19 3.5 4 20.93596 5.878 5 -371.47191 1.010 1.51742 52.43 0.55649 2.46 2.4 6 21.26359 5.680 1.91082 35.25 0.58224 4.97 5.3 7 201.03756 3.078 8 -59.57656 1.029 1.48749 70.44 0.53062 2.45 -1.4 9 -193.21632 DD[9] 10 (St) ∞ 1.292 11 18.56917 4.933 1.49700 81.61 0.53887 3.70 -6.2 16.87 12 -41.16804 2.621 *13 -20.63867 1.000 1.58313 59.38 0.54237 3.05 3.7 *14 -35.83396 3.952 15 325.50755 1.000 1.74400 44.79 0.56560 4.32 3.0 16 19.85611 5.434 1.49700 81.61 0.53887 3.70 -6.2 17 -19.33201 DD

[17] 18 118.65126 1.000 1.48749 70.44 0.53062 2.45 -1.4 19 29.73613 14.109 20 -20.52482 1.500 1.74000 28.30 0.60790 3.11 2.4 21 -39.71670 DD

[21] 28.29 22 208.75166 5.125 1.84666 23.78 0.61923 3.50 1.4 23 -135.57356 18.777 24 ∞ 2.850 1.51680 64.20 0.53430 25 ∞ 1.129

[0282] [Table 5]

[0283] Example 2

[0284]

[0285] [Table 6]

[0286] Example 2

[0287] KA 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 A4 1.2894697E-04 1.6815912E-04 A5 -1.9157405E-06 -3.9879210E-06 A6 -5.4548703E-07 3.8433489E-07 A7 9.9605706E-08 -9.022803708 A8 -1.5444211E-08 8.5412426E-09 A9 1.0067884E-09 -5.0227346E-10 A10 -2.5854550E-11 7.2931536E-12

[0288] [Example 3]

[0289] Figure 10The diagram shows a cross-sectional view and movement trajectory of the wide-angle end structure of the zoom lens of Embodiment 3 when focused on an object at infinity. The zoom lens of Embodiment 3, along the optical axis Z from the object side to the image side, sequentially includes a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, a third lens group G3 with negative refractive power, and a fourth lens group G4 with positive refractive power. The intermediate group GM includes the second lens group G2 and the third lens group G3. The front portion group GMf includes the second lens group G2. The rear portion group GMr includes the third lens group G3. The final group GE includes the fourth lens group G4.

[0290] Lens group G1 consists of four lenses, L11 through L14, arranged sequentially from the object side to the image side. Lens group G2 consists of lens L21, aperture St, lens L22, and lens L23, arranged sequentially from the object side to the image side. Lens group G3 consists of two lenses, L31 and L32, arranged sequentially from the object side to the image side. Lens group G4 consists of lens L41.

[0291] During zooming, the second lens group G2 and the third lens group G3 change their spacing along the optical axis Z from that of adjacent groups, while the first lens group G1 and the fourth lens group G4 remain fixed relative to the image plane Sim. The focusing group includes the entire third lens group G3. The anti-vibration group includes lens L14.

[0292] Regarding the zoom lens of Example 3, the basic lens data is shown in Table 7, the specifications and variable surface spacing are shown in Table 8, the aspherical coefficients are shown in Table 9, and the various aberrations are illustrated in Table 1. Figure 11 .

[0293] [Table 7]

[0294] Example 3

[0295] 1 56.89184 1.694 1.92286 20.88 0.63900 3.94 1.8 2 19.97616 7.793 3 -189.48592 1.260 1.49700 81.61 0.53887 3.70 -6.2 4 25.64305 4.941 1.96300 24.11 0.62126 4.2 3.0 5 190.72948 4.157 6 -55.46940 1.000 1.48749 70.44 0.53062 2.45 -1.4 7 -175.58702 DD[7] 8 16.13878 3.972 1.49700 81.61 0.53887 3.7 -6.2 15.93 9 -65.65560 0.667 10 (St) ∞ 5.810 *11 -62.54010 1.169 1.68948 31.02 0.59874 2.88 0.0 *12 145.82688 3.951 13 -260.43747 2.949 1.49700 81.61 0.53887 3.70 -6.2 14 -16.47960 DD

[14] 15 30.04223 1.500 1.96300 24.11 0.62126 4.2 3.0 16 20.80076 7.772 17 -15.66420 1.000 1.63980 34.47 0.59233 2.76 2.5 18 -32.85641 DD

[18] 21.73 19 -187.09863 3.671 1.92286 20.88 0.63900 3.94 1.8 20 -81.25018 18.784 21 ∞ 2.850 1.51680 64.20 0.53430 22 ∞ 1.132

[0296] [Table 8]

[0297] Example 3

[0298]

[0299] [Table 9]

[0300] Example 3

[0301] KA 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 A4 -2.3183977E-04 -1.4214998E-04 A5 1.9868927E-06 -2.9656599E-06 A6 3.4257964E-07 2.6194127E-06 A7 3.6614054E-07 2.4386812E-08 A8 -3.5045121E-08 -1.6384001E-08 A9 -9.0930354E-10 2.2953942E-10 A10 1.4875183E-10 2.6214402E-11

[0302] [Example 4]

[0303] Figure 12The diagram shows a cross-sectional view and movement trajectory of the wide-angle end structure of the zoom lens of Embodiment 4 when focused on an object at infinity. The zoom lens of Embodiment 4, along the optical axis Z from the object side to the image side, sequentially includes a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, a third lens group G3 with negative refractive power, and a fourth lens group G4 with positive refractive power. The intermediate group GM includes the second lens group G2 and the third lens group G3. The front portion group GMf includes the second lens group G2. The rear portion group GMr includes the third lens group G3. The final group GE includes the fourth lens group G4.

[0304] Lens group G1 consists of five lenses, L11 to L15, arranged sequentially from the object side to the image side. Lens group G2 consists of seven lenses, L21 to L27, arranged sequentially from the object side to the image side. Lens group G3 consists of two lenses, L31 and L32, arranged sequentially from the object side to the image side. Lens group G4 consists of lens L41.

[0305] During zooming, the first lens group G1, the second lens group G2, and the third lens group G3 change their spacing along the optical axis Z from that of adjacent groups, while the fourth lens group G4 remains fixed relative to the image plane Sim. The focusing group includes the entire third lens group G3. The anti-vibration group includes lens L15.

[0306] Regarding the zoom lens of Example 4, the basic lens data is shown in Table 10, the specifications and variable surface spacing are shown in Table 11, the aspherical coefficients are shown in Table 12, and the various aberrations are illustrated in Table 13. Figure 13 .

[0307] [Table 10]

[0308] Example 4

[0309] 1 44.97328 1.250 1.91082 35.25 0.58224 4.97 5.3 2 26.38035 2.904 3 50.52795 1.250 1.90366 31.31 0.59481 4.51 4.0 4 22.61953 6.491 5 -64.44855 1.260 1.49700 81.61 0.53887 3.70 -6.2 6 26.03752 6.210 1.90043 37.37 0.57720 5.19 4.3 7 118.97763 4.503 8 -52.40377 1.031 1.48749 70.44 0.53062 2.45 -1.4 9 -149.01756 DD[9] 10 (St) ∞ 1.000 11 15.96026 4.208 1.48749 70.44 0.53062 2.45 -1.4 17.55 12 178.61656 0.284 13 55.69847 3.342 1.49700 81.61 0.53887 3.70 -6.2 14 -31.56993 1.010 1.59551 39.22 0.58042 2.62 2.4 15 -83.87250 2.167 *16 44.22838 1.000 1.68948 31.02 0.59874 2.88 0.0 *17 -43.57239 2.336 18 -52.16682 3.170 1.75575 24.71 0.62909 3.19 -0.5 19 -12.86196 1.010 1.73800 32.33 0.59005 3.19 5.1 20 24.45061 4.509 1.49700 81.61 0.53887 3.70 -6.2 21 -25.01634 DD

[21] 22 84.38029 1.000 1.49700 81.61 0.53887 3.70 -6.2 23 26.86525 12.089 24 -19.80243 1.000 1.92286 20.88 0.63900 3.94 1.8 25 -28.83430 DD

[25] 26.84 26 257.76070 5.485 1.90366 31.31 0.59481 4.51 4.0 27 -106.66340 18.784 28 ∞ 2.850 1.51680 64.20 0.53430 29 ∞ 1.125

[0310] [Table 11]

[0311] Example 4

[0312]

[0313] [Table 12]

[0314] Example 4

[0315] KA 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 A4 4.4423566E-05 1.0452164E-04 A5 -2.9662980E-06 -5.9427317E-06 A6 1.5237040E-06 2.4767436E-06 A7 1.1900923E-07 2.0860763E-08 A8 -1.8970021E-08 -1.5969660E-08 A9 -1.7565654E-10 6.5536000E-10 A10 2.2906649E-11 -1.8144157E-11

[0316] [Example 5]

[0317] Figure 14The diagram shows a cross-sectional view and movement trajectory of the wide-angle end structure of the zoom lens of Embodiment 5 when focused on an object at infinity. The zoom lens of Embodiment 5, along the optical axis Z from the object side to the image side, sequentially includes a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, a third lens group G3 with negative refractive power, and a fourth lens group G4 with positive refractive power. The intermediate group GM includes the second lens group G2 and the third lens group G3. The front portion group GMf includes the second lens group G2. The rear portion group GMr includes the third lens group G3. The final group GE includes the fourth lens group G4.

[0318] Lens group G1 consists of four lenses, L11 through L14, arranged sequentially from the object side to the image side. Lens group G2 consists of lenses L21, L22, aperture St, L23, and L24, arranged sequentially from the object side to the image side. Lens group G3 consists of two lenses, L31 and L32, arranged sequentially from the object side to the image side. Lens group G4 consists of lens L41.

[0319] During zooming, the first lens group G1, the second lens group G2, and the third lens group G3 change their spacing along the optical axis Z with respect to adjacent groups, while the fourth lens group G4 remains fixed relative to the image plane Sim. The focusing group includes the entire third lens group G3.

[0320] Regarding the zoom lens of Example 5, the basic lens data is shown in Table 13, the specifications and variable surface spacing are shown in Table 14, the aspherical coefficients are shown in Table 15, and the various aberrations are illustrated in Table 16. Figure 15 .

[0321] [Table 13]

[0322] Example 5

[0323] 1 121.76613 1.150 1.95375 32.32 0.59015 5.10 4.9 2 30.82121 3.192 3 68.91678 1.000 1.58313 59.46 0.54336 3.24 3.4 4 23.31262 6.127 5 ∞ 0.960 1.48749 70.39 0.53005 2.48 -1.5 6 24.28656 6.175 1.91082 35.25 0.58224 4.97 5.3 7 199.51444 DD[7] 8 16.68949 4.957 1.49700 81.61 0.53887 3.7 -6.2 18.00 9 -46.07000 0.100 *10 -38.36541 2.192 1.58660 59.01 0.54152 2.7 5.1 *11 -64.49761 3.002 12 (St) ∞ 3.003 13 -55.10725 0.850 1.67003 47.20 0.56411 3.61 4.7 14 17.65797 5.649 1.49700 81.61 0.53887 3.70 -6.2 15 -17.65797 DD

[15] 16 42.35716 0.850 1.72916 54.67 0.54534 4.05 3.4 17 27.14128 12.500 18 -18.97503 0.850 1.91082 35.25 0.58224 4.97 5.3 19 -32.67690 DD

[19] 25.41 20 ∞ 6.236 1.92119 23.96 0.62025 3.84 2.4 21 -127.88100 18.775 22 ∞ 2.850 1.51680 64.20 0.53430 23 ∞ 1.127

[0324] [Table 14]

[0325] Example 5

[0326]

[0327] [Table 15]

[0328] Example 5

[0329] KA 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 A4 8.4920932E-05 1.4039088E-04 A5 -1.7647480E-07 -1.8591463E-06 A6 1.6500597E-07 1.1655413E-06 A7 6.9139011E-08 -1.2697382E-07 A8 -2.3300086E-08 2.3071068E-09 A9 1.9163258E-09 4.0206908E-10 A10 -5.5644267E-11 -2.6214400E-11

[0330] [Example 6]

[0331] Figure 16The diagram shows a cross-sectional view and movement trajectory of the wide-angle end structure of the zoom lens of Embodiment 6 when focused on an object at infinity. The zoom lens of Embodiment 6, along the optical axis Z from the object side to the image side, sequentially includes a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, a third lens group G3 with negative refractive power, and a fourth lens group G4 with positive refractive power. The intermediate group GM includes the second lens group G2 and the third lens group G3. The front portion group GMf includes the second lens group G2. The rear portion group GMr includes the third lens group G3. The final group GE includes the fourth lens group G4.

[0332] Lens group G1 consists of five lenses, L11 to L15, arranged sequentially from the object side to the image side. Lens group G2 consists of four lenses, L21 to L24, arranged sequentially from the object side to the image side. Lens group G3 consists of two lenses, L31 and L32, arranged sequentially from the object side to the image side. Lens group G4 consists of lens L41.

[0333] During zooming, the first lens group G1, the second lens group G2, and the third lens group G3 change their spacing along the optical axis Z from that of adjacent groups, while the fourth lens group G4 remains fixed relative to the image plane Sim. The focusing group includes the entire third lens group G3. The anti-vibration group includes lens L15.

[0334] Regarding the zoom lens of Example 6, the basic lens data is shown in Table 16, the specifications and variable surface spacing are shown in Table 17, the aspherical coefficients are shown in Table 18, and the various aberrations are illustrated in Table 19. Figure 17 .

[0335] [Table 16]

[0336] Example 6

[0337] 1 39.98959 1.850 1.74000 28.30 0.60790 3.11 2.4 2 24.37501 3.848 3 54.94631 1.000 1.55200 70.73 0.54190 3.74 -2.9 4 20.66326 6.032 5 -208.92870 1.010 1.51742 52.43 0.55649 2.46 2.4 6 21.63078 7.285 1.91082 35.25 0.58224 4.97 5.3 7 268.18627 2.943 8 -61.85589 1.039 1.48749 70.42 0.53039 2.43 -1.8 9 -205.40726 DD[9] 10 (St) ∞ 1.000 11 16.30809 5.105 1.49700 81.59 0.53701 3.70 -6.6 16.81 12 -37.42224 0.100 *13 -54.52659 1.250 1.58313 59.38 0.54237 3.05 3.7 *14 -204.87140 4.643 15 -255.75168 1.000 1.74400 44.79 0.56560 4.32 3.0 16 17.51443 6.989 1.47329 78.16 0.54930 3.66 -5.9 17 -17.66529 DD

[17] 18 235.18307 3.750 1.48749 70.44 0.53062 2.45 -1.5 19 26.85953 10.841 20 -18.10750 1.500 1.74000 28.30 0.60790 3.11 2.4 21 -39.64836 DD

[21] 28.31 22 92.47888 11.342 1.84666 23.78 0.61923 3.50 1.4 23 -194.68781 12.645 24 ∞ 2.850 1.51680 64.20 0.53430 25 ∞ 1.123

[0338] [Table 17]

[0339] Example 6

[0340]

[0341] [Table 18]

[0342] Example 6

[0343] KA 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 A4 1.0426306E-04 1.7318619E-04 A5 -2.5911222E-06 -4.3440832E-06 A6 -1.3693691E-07 7.6826995E-07 A7 7.2961792E-08 -9.2639546E-08 A8 -2.0983661E-08 2.5353790E-09 A9 1.3814194E-09 -3.5684015E-10 A10 -2.1618987E-11 2.6214400E-11

[0344] [Example 7]

[0345] Figure 18The diagram shows a cross-sectional view and movement trajectory of the wide-angle end structure of the zoom lens of Embodiment 7 when focused on an object at infinity. The zoom lens of Embodiment 7, along the optical axis Z from the object side to the image side, sequentially includes a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with negative refractive power, and a fifth lens group G5 with positive refractive power. The intermediate group GM includes the second lens group G2, the third lens group G3, and the fourth lens group G4. The front portion group GMf includes the second lens group G2 and the third lens group G3. The rear portion group GMr includes the fourth lens group G4. The final group GE includes the fifth lens group G5.

[0346] Lens group G1 consists of four lenses, L11 to L14, arranged sequentially from the object side to the image side. Lens group G2 consists of two lenses, L21 and L22, arranged sequentially from the object side to the image side. Lens group G3 consists of four lenses, L11 (aperture st) and L31 to L34, arranged sequentially from the object side to the image side. Lens group G4 consists of three lenses, L41 to L43, arranged sequentially from the object side to the image side. Lens group G5 consists of lens L51.

[0347] During zooming, the second lens group G2, the third lens group G3, and the fourth lens group G4 change their spacing along the optical axis Z from that of adjacent groups, while the first lens group G1 and the fifth lens group G5 remain fixed relative to the image plane Sim. The focusing group includes the entire second lens group G2.

[0348] Regarding the zoom lens of Example 7, the basic lens data is shown in Table 19, the specifications and variable surface spacing are shown in Table 20, the aspherical coefficients are shown in Table 21, and the various aberrations are illustrated in Table 22. Figure 19 .

[0349] [Table 19]

[0350] Example 7

[0351] 1 39.69500 1.500 1.92119 23.96 0.62025 3.84 2.4 2 20.29884 7.846 *3 63.03240 1.500 1.58313 59.38 0.54237 3.05 3.7 *4 19.66119 8.773 5 -70.63009 2.010 1.49700 81.61 0.53887 3.70 -6.2 6 26.83729 5.250 1.84666 23.78 0.61923 3.50 1.4 7 90.33591 DD[7] 8 22.89876 3.000 1.61800 63.33 0.54414 3.67 -3.6 18.70 9 319.45534 7.421 *10 -58.08644 3.000 1.58313 59.38 0.54237 3.05 3.7 *11 -117.44311 DD

[11] 12 (St) ∞ 1.000 13 30.63696 7.444 1.72047 34.71 0.58350 3.19 3.5 14 -18.54761 1.000 1.91082 35.25 0.58224 4.97 5.3 15 19.72774 4.711 1.49700 81.61 0.53887 3.7 -6.2 16 675.80986 0.100 *17 36.52058 5.311 1.49710 81.56 0.53848 3.64 -5.5 *18 -23.87397 DD

[18] 19 27.79508 1.000 1.78800 47.37 0.55598 4.3 4.4 20 12.93313 7.899 1.49700 81.61 0.53887 3.70 -6.2 21 24.76814 3.613 *22 -75.32474 1.632 1.68948 31.02 0.59874 2.88 0.0 *23 97.86013 DD

[23] 23.59 24 1168.45304 5.943 1.91082 35.25 0.58224 4.97 5.3 25 -63.35665 15.722 26 ∞ 2.850 1.51680 64.20 0.53430 27 ∞ 1.134

[0352] [Table 20]

[0353] Example 7

[0354]

[0355] [Table 21]

[0356] Example 7

[0357]

[0358]

[0359] KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 0.0000000E+00 0.0000000E+00 A4 7.1174964E-07 9.0712036E-07 -4.7563389E-05 -3.2226551E-05 A5 4.7209889E-07 -3.9052718E-07 1.3180024E-06 -3.4319459E-07 A6 -1.3286512E-07 2.7997124E-08 7.7425059E-08 3.2104805E-07 A7 1.1039354E-08 -8.7558245E-10 -4.6460082E-09 -1.3287663E-08 A8 3.5916008E-10 -1.4568551E-10 -4.6981680E-10 -1.3322015E-09 A9 -9.6668909E-11 1.0823575E-11 1.1106969E-10 1.4823734E-10 A10 3.4252859E-12 -7.1189034E-13 -7.7800126E-12 -5.7904702E-12

[0360] [Example 8]

[0361] Figure 20 The diagram shows a cross-sectional view and movement trajectory of the wide-angle end structure of the zoom lens of Embodiment 8 when focused on an object at infinity. The zoom lens of Embodiment 8, along the optical axis Z from the object side to the image side, sequentially includes a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, a third lens group G3 with negative refractive power, a fourth lens group G4 with positive refractive power, and a fifth lens group G5 with positive refractive power. The intermediate group GM includes the second lens group G2, the third lens group G3, and the fourth lens group G4. The front portion group GMf includes the second lens group G2. The rear portion group GMr includes the third lens group G3 and the fourth lens group G4. The final group GE includes the fifth lens group G5.

[0362] Lens group G1 consists of four lenses, L11 to L14, arranged sequentially from the object side to the image side. Lens group G2 consists of two lenses, L21 and L22, an aperture (St), and four lenses, L23 to L26, arranged sequentially from the object side to the image side. Lens group G3 consists of three lenses, L31 to L33, arranged sequentially from the object side to the image side. Lens group G4 includes lens L41. Lens group G5 includes lens L51.

[0363] During zooming, lens groups G1, G2, G3, and G4 change their spacing along the optical axis Z from that of adjacent groups, while lens group G5 remains fixed relative to the image plane Sim. The focusing group consists of lenses L21 and L22.

[0364] Regarding the zoom lens of Example 8, the basic lens data is shown in Table 22, the specifications and variable surface spacing are shown in Table 23, the aspherical coefficients are shown in Table 24, and the various aberrations are illustrated in Table 25. Figure 22 .

[0365] [Table 22]

[0366] Example 8

[0367] 1 44.62317 1.850 1.90366 31.31 0.59481 3.19 4.0 2 20.83349 7.997 *3 64.27125 2.255 1.58313 59.38 0.54237 3.05 3.7 *4 19.83007 14.377 5 -34.46726 3.940 1.49700 81.61 0.53887 3.70 -6.2 6 63.36355 4.837 1.84666 23.78 0.61923 3.50 1.4 7 -148.22321 DD[7] 8 22.98470 3.000 1.58313 59.37 0.54345 3.19 3.5 19.5 9 226.52076 9.179 *10 -56.76410 2.150 1.58313 59.38 0.54237 3.05 3.7 *11 -74.49170 DD

[11] 12 (St) ∞ 1.000 13 26.77357 5.498 1.73800 32.33 0.59005 3.19 5.1 14 27.90173 1.000 2.00100 29.13 0.59952 5.12 4.4 15 25.62780 4.630 1.43700 95.10 0.53364 3.53 -6.3 16 -124.48506 0.100 *17 28.51624 6.570 1.49710 81.56 0.53848 3.64 -5.5 *18 -27.06196 DD

[18] 19 31.58398 2.467 1.88300 40.80 0.56557 5.42 5.1 20 11.84725 4.371 1.49700 81.61 0.53887 3.70 -6.2 21 25.09888 3.547 *22 -38.38868 4.787 1.68948 31.02 0.59874 2.88 0.0 *23 118.31093 DD

[23] 24 ∞ 2.570 1.98613 16.48 0.66558 3.54 8.5 25 -129.57389 DD

[25] 36.26 26 ∞ 4.703 1.86966 20.02 0.64349 3.37 1.0 27 -76.72190 13.790 28 ∞ 2.850 1.51680 64.20 0.53430 29 ∞ 1.129

[0368] [Table 23]

[0369] Example 8

[0370]

[0371] [Table 24]

[0372] Example 8

[0373] KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 0.0000000E+00 0.0000000E+00 A4 3.5870440E-05 2.3281112E-05 2.8687032E-05 4.6534634E-05 A5 -2.3734946E-06 -2.5599860E-06 -5.3061919E-08 6.9839493E-07 A6 -3.6226413E-08 -2.0630576E-08 2.5480340E-07 1.6193543E-07 A7 6.4859358E-09 1.7665547E-09 3.7326117E-09 9.9919100E-09 A8 9.6608518E-11 -1.1523211E-10 -1.1772298E-09 7.6898898E-11 A9 -1.7375638E-11 3.0890582E-11 -1.2046567E-12 -1.4127340E-10 A10 3.5815091E-13 -1.4729026E-12 1.0593069E-12 7.0569659E-12

[0374] KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 0.0000000E+00 0.0000000E+00 A4 -1.2766474E-05 7.4543629E-07 -6.6029575E-05 -3.4285567E-05 A5 2.7327401E-07 -2.1540238E-07 1.9288596E-06 -1.3136864E-06 A6 -1.0700992E-07 4.8985509E-09 -7.3753189E-08 3.3305289E-07 A7 8.5030244E-09 5.9851384E-10 -1.7500291E-08 -1.2424349E-08 A8 1.0966673E-10 -8.7746543E-12 3.8103247E-10 -1.3104483E-09 A9 -6.6128529E-11 -1.5763851E-11 3.3635421E-10 1.6342681E-10 A10 2.8035224E-12 8.2341267E-13 -2.4915940E-11 -5.9543794E-12

[0375] [Example 8A]

[0376] Example 8A is a variation of Example 8. Figure 21 The diagram shows a cross-sectional view and movement trajectory of the wide-angle end structure of the zoom lens of Embodiment 8A when focused on an object at infinity. Embodiment 8A differs from Embodiment 8 in that the rear portion group GMr only includes the third lens group G3, and while the fourth lens group G4 is included within the middle group GM, it is neither included within the front portion group GMf nor the rear portion group GMr. Apart from the above, Embodiment 8A is identical to Embodiment 8. The basic lens data, specifications, variable surface spacing, aspherical coefficients, and aberration diagrams of Embodiment 8A are also the same as those of Embodiment 8.

[0377] [Example 9]

[0378] Figure 23 The diagram shows a cross-sectional view and movement trajectory of the wide-angle end structure of the zoom lens of Embodiment 9 in a state where it is focused on an object at infinity. The zoom lens of Embodiment 9 includes, along the optical axis Z from the object side to the image side, a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, and a third lens group G3 with positive refractive power.

[0379] Lens group G1 consists of four lenses, L11 to L14, arranged sequentially from the object side to the image side. Lens group G2 consists of two lenses, L21 and L22, an aperture (St), and four lenses, L23 to L26, arranged sequentially from the object side to the image side. Lens group G3 consists of two lenses, L31 and L32, arranged sequentially from the object side to the image side.

[0380] The middle group GM includes the second lens group G2. The front part group GMf includes lenses L21 and L22, aperture St, and lenses L23 and L24. The rear part group GMr includes lenses L25 and L26. The final group GE includes the third lens group G3.

[0381] During zooming, the first lens group G1 and the second lens group G2 change their spacing along the optical axis Z with respect to the adjacent groups, while the third lens group G3 remains fixed relative to the image plane Sim. The focusing group includes lens L25.

[0382] Regarding the zoom lens of Example 9, the basic lens data is shown in Table 25, the specifications and variable surface spacing are shown in Table 26, the aspherical coefficients are shown in Table 27, and the various aberrations are illustrated in Table 28. Figure 24.

[0383] [Table 25]

[0384] Example 9

[0385] 1 49.62542 1.500 1.96300 24.11 0.62126 4.20 3.0 2 23.94581 6.878 3 64.00404 1.500 1.72916 54.68 0.54451 4.18 4.0 4 25.10976 8.985 5 -64.45664 0.960 1.48749 70.39 0.53005 2.48 -1.5 6 30.30271 6.750 1.95375 32.32 0.59015 5.10 4.9 7 -1849.80094 DD[7] 8 18.50187 7.000 1.59522 67.73 0.54426 4.17 -6.0 16.00 9 -52.87445 1.000 *10 -27.93008 2.396 1.58660 59.01 0.54152 2.7 5.2 *11 -94.28961 1.750 12 (St) ∞ 1.674 13 -29.94960 0.850 1.67300 38.26 0.57580 3.01 3.8 14 35.25218 4.060 1.53775 74.70 0.53936 3.64 -4.3 15 -15.87563 DD

[15] 16 26.58098 0.850 1.74400 44.79 0.56560 4.32 3.0 17 21.56987 DD

[17] 18 -29.48283 0.850 1.69895 30.13 0.60298 2.96 3.6 19 -41.07208 DD

[19] 22.96 20 -165.69742 5.341 1.49700 81.61 0.53887 3.70 -6.2 21 -33.54719 1.500 1.90525 35.04 0.58486 4.83 5.5 22 -54.73449 23.578 23 ∞ 2.850 1.51680 64.20 0.53430 24 ∞ 1.095

[0386] [Table 26]

[0387] Example 9

[0388]

[0389] [Table 27]

[0390] Example 9

[0391] KA 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 A4 1.4951659E-04 2.1394243E-04 A5 -5.8044374E-06 -6.9020590E-06 A6 -1.5749888E-07 6.5613684E-07 A7 7.4326647E-08 -9.1963584E-08 A8 -2.2227321E-08 7.8292688E-09 A9 2.1276560E-09 -4.7593712E-10 A10 -7.7805047E-11 -9.3255943E-12

[0392] [Example 10]

[0393] Figure 25 The diagram shows a cross-sectional view and movement trajectory of the wide-angle end structure of the zoom lens of Embodiment 10 when focused on an object at infinity. The zoom lens of Embodiment 10, along the optical axis Z from the object side to the image side, sequentially includes a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with negative refractive power, and a fifth lens group G5 with positive refractive power. The intermediate group GM includes the second lens group G2, the third lens group G3, and the fourth lens group G4. The front portion group GMf includes the second lens group G2 and the third lens group G3. The rear portion group GMr includes the fourth lens group G4. The final group GE includes the fifth lens group G5.

[0394] Lens group G1 consists of four lenses, L11 to L14, arranged sequentially from the object side to the image side. Lens group G2 consists of two lenses, L21 and L22, arranged sequentially from the object side to the image side. Lens group G3 consists of four lenses, L11 (aperture st) and L31 to L34, arranged sequentially from the object side to the image side. Lens group G4 consists of three lenses, L41 to L43, arranged sequentially from the object side to the image side. Lens group G5 consists of lens L51.

[0395] During zooming, the second lens group G2, the third lens group G3, and the fourth lens group G4 change their spacing along the optical axis Z from that of adjacent groups, while the first lens group G1 and the fifth lens group G5 remain fixed relative to the image plane Sim. The focusing group includes the entire second lens group G2.

[0396] Regarding the zoom lens of Example 10, the basic lens data is shown in Table 28, the specifications and variable surface spacing are shown in Table 29, the aspherical coefficients are shown in Table 30, and the various aberrations are illustrated in Table 30. Figure 26 .

[0397] [Table 28]

[0398] Example 10

[0399]

[0400] [Table 29]

[0401] Example 10

[0402]

[0403] [Table 30]

[0404] Example 10

[0405] KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 0.0000000E+00 0.0000000E+00 A4 4.1300441E-05 3.0099143E-05 5.8666005E-05 6.2126215E-05 A5 -2.4033683E-06 -1.6543125E-06 -1.1082747E-07 -1.8583677E-06 A6 -4.8681225E-08 -8.7456445E-08 -2.0831316E-08 6.8611949E-07 A7 5.3290405E-09 1.0604481E-09 3.2732275E-08 -1.0884906E-07 A8 1.7877787E-10 -9.8343487E-12 -5.0650804E-09 1.1559071E-08 A9 -1.7943006E-11 3.5349032E-11 3.6587411E-10 -6.5016237E-10 A10 3.2566028E-13 -1.6366418E-12 -1.0976748E-11 1.5338197E-11

[0406] KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 0.0000000E+00 0.0000000E+00 A4 -9.5480325E-06 5.1436650E-06 -2.2230188E-05 -1.4798556E-06 A5 8.5764274E-07 3.5383265E-07 -2.5662668E-06 -3.9669057E-06 A6 -1.3625695E-07 -5.7514914E-08 6.2977636E-08 1.9581443E-07 A7 4.6449896E-09 1.6762465E-09 1.5501381E-08 1.5953243E-08 A8 8.2283721E-10 1.7360953E-10 -1.3231686E-09 -8.6203549E-10 A9 -8.4896133E-11 -1.4084261E-11 7.9174894E-11 -4.6746994E-11 A10 2.3243095E-12 8.0801659E-14 -4.3970839E-12 2.4548978E-12

[0407] Tables 31, 32, and 33 show the corresponding values ​​of conditional expressions (1) to (30) for the zoom lens in the above embodiments. In Embodiment 1, there are two convex surfaces related to conditional expressions (5) and (6), so the corresponding values ​​of the object-side convex surfaces are recorded in the upper paragraph, and the corresponding values ​​of the image-side convex surfaces are recorded in the lower paragraph. This recording method related to conditional expressions (5) and (6) is also the same in Embodiments 3, 9, and 10.

[0408] [Table 31]

[0409]

[0410] [Table 32]

[0411]

[0412] [Table 33]

[0413]

[0414] Next, the camera device according to the embodiments of the present invention will be described. Figure 27 and Figure 28 The diagram shows an external view of a camera 30, an imaging device according to an embodiment of the present invention. Figure 27 This is a stereoscopic view of camera 30 viewed from the front side. Figure 28 This is a perspective view of the camera 30 as seen from the rear side. The camera 30 is a so-called mirrorless digital camera, which can be detachably fitted with an interchangeable lens 20. The interchangeable lens 20 is configured to include a zoom lens 1 according to an embodiment of the present invention housed within a lens barrel.

[0415] The camera 30 includes a camera body 31, and a shutter button 32 and a power button 33 are provided on the upper surface of the camera body 31. Furthermore, an operation unit 34, an operation unit 35, and a display unit 36 ​​are provided on the back of the camera body 31. The display unit 36 ​​can display the captured image and the image existing within the field of view before shooting.

[0416] A camera body 31 has a camera aperture for light from the subject to enter at the center of the front. A bayonet 37 is provided at the position corresponding to the camera aperture, and the interchangeable lens 20 is mounted on the camera body 31 via the bayonet 37.

[0417] The camera body 31 contains an imaging element such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) that outputs an image signal corresponding to the image of the subject formed by the interchangeable lens 20, a signal processing circuit that processes the image signal output from the imaging element to generate an image, and a recording medium for recording the generated image. In the camera 30, still images or moving images can be captured by pressing the shutter button 32, and the image data obtained is recorded in the aforementioned recording medium.

[0418] The above description, through examples and embodiments, illustrates the technology of the present invention. However, the technology of the present invention is not limited to the above examples and embodiments, and various modifications are possible. For example, the radius of curvature, surface spacing, refractive index, dispersion coefficient, and aspherical coefficient of each lens are not limited to the values ​​shown in the above embodiments, and other values ​​may also be used.

[0419] Furthermore, the imaging device involved in the embodiments of the present invention is not limited to the examples described above. For example, it can also be configured as a camera other than a mirrorless camera, a film camera, a video camera, or other similar devices.

[0420] Symbol Explanation

[0421] 1-Zoom lens, 20-Interchangeable lens, 30-Camera, 31-Camera body, 32-Shutter button, 33-Power button, 34, 35-Operation unit, 36-Display unit, 37-Leg mount, Dfoct-Focusing group movement, DpM-Position difference, DStw-Distance, ED-Effective diameter, G1-First lens group, G2-Second lens group, G3-Third lens group, G4-Fourth lens group, G5-Fifth lens group, GE-Final group, GM-Intermediate group, GMf-Front side group, G Mr - Rear side group, HMfa, HMfb, HMra, HMrb - Height, L11~L51, Lx - Lens, ma, ta, wa - On-axis beam, mb, tb, wb - Beam with maximum image height, NL - Normal, P - Effective diameter end, PP - Optical component, Sim - Image plane, St - Aperture, wa1 - On-axis edge ray, wb1 - Principal ray, Xa - On-axis beam, Xb - Off-axis beam, Xb1 - Ray, Z - Optical axis, α - Angle, ωt, ωw - Maximum half angle of view.

Claims

1. A zoom lens, comprising, from the object side to the image side, a first lens group with negative refractive power, an intermediate lens group, and a final lens group. The intermediate group consists of two or three lens groups. The final group consists of only one lens group. During zooming, the interval between the first lens group and the intermediate group changes, the interval between the intermediate group and the final group changes, and the interval between adjacent lens groups within the intermediate group changes. During focusing, at least a portion of the intermediate group moves along the optical axis as a focusing group. The first lens group and the final group are fixed relative to the image plane. The first lens group is a negative meniscus lens with a convex surface on the object-side surface, including the object-side surface. The intermediate group, from the object side to the image side, includes an anterior portion with positive refractive power and a posterior portion with negative refractive power. The front part group consists of one or two lens groups with positive refractive power. The rear portion consists of a lens group with negative refractive power. The back focal length of the entire system at the wide-angle end, with the air equivalent distance set to Bfw when focusing on an object at infinity, is... Set the focal length of the entire system at the wide-angle end, with the focus on an object at infinity, to fw. Set the maximum half-angle of the wide-angle end to ωw when focusing on an object at infinity. The paraxial radius of curvature of the lens surface closest to the object in the front part group is set to RMff. The paraxial radius of curvature of the lens surface closest to the image side of the front part group is set as RMfr. Let the paraxial radius of curvature of the object-side surface of the negative meniscus lens be R1f. When the paraxial radius of curvature of the image-side surface of the negative meniscus lens is set to R1r, The zoom lens satisfies the following conditions (1), (8-3), and (10-1): 0.35<Bfw / (fw×tan|ωw|)<1.5 (1) -0.5<(RMff+RMfr) / (RMff-RMfr)<1 (8-3) 1.5<(R1f+R1r) / (R1f-R1r)<4.3 (10-1).

2. The zoom lens according to claim 1, wherein, The amount of movement of the focus group when changing from focusing on an object at infinity at the telephoto end to a magnification of -0.1x is set as Dfoct. Let DpM be the difference in the optical axis direction between the position of the lens surface closest to the object in the intermediate group at the telephoto end (focused on an object at infinity) and the position of the lens surface closest to the object in the intermediate group at the wide-angle end. The zoom lens satisfies the following condition (2): 0.005<|Dfoct / DpM|<0.3 (2).

3. The zoom lens according to claim 1 or 2, wherein, The effective diameter of the lens surface closest to the object in the middle group is set to EDMf. When the effective diameter of the lens surface closest to the image side of the intermediate group is set to EDMr... The zoom lens satisfies the following condition (3): 0.3<EDMf / EDMr<1.5 (3).

4. The zoom lens according to claim 1 or 2, wherein, When the sum of the distance along the optical axis from the lens surface closest to the object side of the first lens group at the wide-angle end to the lens surface closest to the image side of the final group at the wide-angle end, and Bfw, is set as TLw, The zoom lens satisfies the following condition (4): 2.5<TLw / (fw×tan|ωw|)<7 (4).

5. The zoom lens according to claim 1 or 2, wherein, When the angle between the normal to the lens surface at the effective diameter end of the lens surface and the optical axis is defined as α, and the unit of α is defined as degrees, The rear portion group includes one or more convex lens surfaces facing the air that satisfy the following condition (5): 13＜|α|＜50 （5）。 6. The zoom lens according to claim 5, wherein, An aperture is disposed on the side closest to the object in the middle group or inside the middle group. The distance along the optical axis from the aperture to the convex lens surface at the wide-angle end when focusing on an object at infinity is defined as DStw. When the focal length of the rear portion group at the wide-angle end is set to fMrw while focusing on an object at infinity, The rear portion group includes one or more convex lens surfaces that satisfy the following condition (6): 0.05<DStw / |fMrw|<2.5 (6).

7. The zoom lens according to claim 1 or 2, wherein, When focusing on an object at infinity, the height of the principal ray from the optical axis at the maximum image height of the lens surface closest to the image side of the front part of the wide-angle end is set as HMfb. Let HMfa be the height of the on-axis edge ray from the optical axis of the lens surface closest to the image side of the front part group of the wide-angle end when focusing on an object at infinity. The height of the principal ray from the optical axis of the lens surface closest to the image side of the rear part group at the wide-angle end when focusing on an object at infinity is defined as HMrb. When the height of the axial edge ray from the optical axis of the lens surface closest to the image side of the rear portion group at the wide-angle end, in a state where the object is focused at infinity, is set to HMra, The zoom lens satisfies the following condition (7): 0.08<(HMfb / HMfa) / (HMrb / HMra)<0.8 (7).

8. The zoom lens according to claim 1 or 2, wherein, During focusing, at least a portion of the rear group moves along the optical axis, while the other groups remain fixed relative to the image plane.

9. The zoom lens according to claim 1 or 2, wherein, During focusing, at least a portion of the front group moves along the optical axis, while the other groups remain fixed relative to the image plane.

10. The zoom lens according to claim 1 or 2, wherein, The rear-side portion includes an image-side negative lens with a convex image-side surface.

11. The zoom lens according to claim 10, wherein, The rear part group is an object-side negative lens that is closer to the object side than the image-side negative lens, including the object-side surface which is convex.

12. The zoom lens according to claim 1 or 2, wherein, When focusing on an object at infinity, the distance from the image plane to the exit pupil at the wide-angle end is set to Pexpw. The zoom lens satisfies the following condition (9): 0.5 < Pexpw / fw < 5 (9).

13. The zoom lens according to claim 1 or 2, wherein, The first lens group includes two or more negative meniscus lenses whose object-side surfaces are convex.

14. The zoom lens according to claim 1 or 2, wherein, When the refractive index of the positive lens included in the first lens group relative to the d-line is set to N1p, The first lens group includes one or more positive lenses that satisfy the following condition (11): 1.6 < N1p < 2.15 (11).

15. The zoom lens according to claim 1 or 2, wherein, When the focal length of the first lens group is set to f1... The zoom lens satisfies the following condition (12): 0.3<fw / |f1|<1.5 (12).

16. The zoom lens according to claim 1 or 2, wherein, When the focal length of the intermediate group at the wide-angle end is set to fMw while focusing on an object at infinity, The zoom lens satisfies the following condition (13): 0.4<fw / fMw<1.5 (13).

17. The zoom lens according to claim 1 or 2, wherein, When the focal length of the focusing group is set to ffoc. The zoom lens satisfies the following condition (14): 0.05<fw / |ffoc|<2.5 (14).

18. The zoom lens according to claim 1 or 2, wherein, When the average weight of all lenses included in the intermediate group is set to GMave, The zoom lens satisfies the following condition (15): 3 < GMave < 4.2 (15).

19. The zoom lens according to claim 1 or 2, wherein, The temperature coefficient of the relative refractive index with respect to the d-line within the range of 20°C to 40°C for the negative lens included in the first lens group is set as (dN1n / dT) × 10. -6 Set the unit of dN1n / dT to K. -1 In this case, The first lens group includes one or more negative lenses that satisfy the following condition (16): -15<dN1n / dT<0 (16).

20. The zoom lens according to claim 1 or 2, wherein, The zoom lens satisfies the following condition (1-1): 0.45<Bfw / (fw×tan|ωw|)<1.1 (1-1).

21. The zoom lens according to claim 1 or 2, wherein, The zoom lens satisfies the following condition (1-2): 0.5<Bfw / (fw×tan|ωw|)<0.85 (1-2).

22. The zoom lens according to claim 1 or 2, wherein, During zooming, the final group is fixed relative to the image plane.

23. A camera device comprising a zoom lens according to any one of claims 1 to 22.

Images