Large-aperture zoom lens and camera device

Abstract

The utility model relates to a large-aperture zoom lens and a camera device, six lens groups are sequentially configured from an object side, the six lens groups comprise a third lens group with positive focal power, and a lens L31 with positive focal power, a lens L32 with positive focal power and a lens L33 with negative focal power closest to an image plane side are respectively distributed from a side close to the object side. Meanwhile, the interval between the positive focal power lens L32 and the negative focal power lens L33 is the widest in the third lens group. According to the utility model, rapid and automatic focusing can be realized in the zoom range, the breathing effect in the focusing process is well controlled, and meanwhile, the manufacturing cost of the lens is well controlled because the use number of the aspherical lenses is controlled.

Description

Technical Field

[0001] This utility model relates to large-aperture zoom lenses and imaging devices, and particularly to zoom lenses and imaging devices suitable for digital still cameras and digital cameras that use solid-state imaging elements. Background Technology

[0002] As solid-state imaging elements have become widespread in digital still cameras, digital camcorders, and other imaging devices, especially mirrorless digital photography and videography devices, the demand for high-performance, portable photographic and videography optical systems has increased rapidly. The market has also created a demand for zoom lenses with fast autofocus.

[0003] Existing zoom optical systems have a small aperture (open F-number of about 4.0), which is not conducive to imaging in darker environments, nor is it conducive to obtaining a good background blur effect when shooting portraits or close-ups. At the same time, they use a lot of aspherical lenses (more than 4), which is not conducive to controlling manufacturing costs. Utility Model Content

[0004] In view of the problems existing in the prior art, the purpose of this utility model is to provide a large-aperture zoom lens and camera device, which can focus quickly and reduce manufacturing costs while having a large light-gathering aperture.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A large-aperture zoom lens has the shortest total length at the wide-angle end. During the zoom process towards the telephoto end, six lens groups are arranged sequentially from the object side: a first lens group with positive optical power, a second lens group with negative optical power, a third lens group with positive optical power, a fourth lens group with positive optical power, a fifth lens group with negative optical power, and a sixth lens group with optical power.

[0007] The first and second lens groups are located on the object side of the aperture stop S and belong to the front half lens group; the third to sixth lens groups are located on the image plane side of the aperture stop S and belong to the rear half lens group; when the photographed object moves closer from infinity, the fifth lens group moves from the object side to the image plane side to achieve the focusing function.

[0008] The third lens group consists of a lens L31 with positive optical power, a lens L32 with positive optical power, and a lens L33 with negative optical power, arranged sequentially from the object side to the image plane side; the interval between lenses L32 and L33 is the widest in the third lens group.

[0009] The object-side surface of lens L31 in the third lens group convexes towards the object side, and the image-side surface convexes towards the image plane side; and the third lens group satisfies the following conditions:

[0010] (1) 0.2 <d32 / T3<0.6;

[0011] Where d32 is the interval between lens L32 and lens L33 in the third lens group, and T3 is the total length of the third lens group.

[0012] The third lens group also satisfies the following conditions:

[0013] (2)71 <vd31<96;

[0014] (3)1.0<(2-nd31)*200 / vd31<1.3;

[0015] (4)71 <vd32<96;

[0016] (5)1.0<(2-nd31)*200 / vd32<1.3;

[0017] Wherein, vd31 and nd31 are the d-line dispersion coefficient and d-line refractive index of lens L31 in the third lens group, respectively; vd32 and nd32 are the d-line dispersion coefficient and d-line refractive index of lens L32 in the third lens group, respectively.

[0018] The first lens group includes a negative power lens L11 near the object side and a positive power lens L12 near the image plane side.

[0019] The second lens group includes a negative optical power lens L21, a negative optical power lens L22, a positive optical power lens L23, and a lens L24 with negative optical power, arranged sequentially from the object side to the image plane side, wherein lens L22 and lens L23 constitute a combined lens.

[0020] The second lens group satisfies the following conditions:

[0021] (6)2.5 <f2e / f2<6.0;

[0022] Where f2e is the focal length of lens L24, and f2 is the focal length of the second lens group.

[0023] The first lens group and the second lens group satisfy the following conditions:

[0024] (7)3.0 <f1 / f4<7.0;

[0025] Where f1 is the focal length of the first lens group and f4 is the focal length of the fourth lens group.

[0026] The fifth and sixth lens groups satisfy the following conditions:

[0027] (8) 0.7 <frw / frt<1.2;

[0028] Where frw is the combined focal length of the fifth lens group G5 and the sixth lens group G6 at the wide-angle end, and frt is the combined focal length of the fifth lens group G5 and the sixth lens group G6 at the telephoto end.

[0029] A camera device includes a large-aperture zoom lens as described above, and an imaging element located on the image plane side of the zoom lens and converting the optical image formed by the zoom lens into an electrical signal.

[0030] By adopting the above scheme, this utility model has a large light-passing aperture and uses a simple fifth lens group as the focusing lens, thereby achieving fast autofocus within its zoom range. At the same time, this utility model balances the aberration effects of the front and rear half lens groups through the structural design of the third lens group G3, which helps to control the overall length of the lens, while reducing the use of aspherical lenses, achieving a compact structure and reducing costs.

[0031] Furthermore, by setting the focal length parameters of the fifth lens group G5 and the sixth lens group G6 on the image plane side, this invention can reduce the breathing effect during focusing while ensuring close-range imaging performance. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the zoom lens structure according to Embodiment 1 of this utility model;

[0033] Figure 2 This is a diagram showing spherical aberration, astigmatism, and distortion at the wide-angle end of Example 1;

[0034] Figure 3 This is a diagram showing spherical aberration, astigmatism, and distortion during zoom in Example 1;

[0035] Figure 4 This is a diagram showing spherical aberration, astigmatism, and distortion at the telescope of Example 1;

[0036] Figure 5 This is a schematic diagram of the zoom lens structure in Embodiment 2;

[0037] Figure 6 This is a diagram showing spherical aberration, astigmatism, and distortion at the wide-angle end of Example 2;

[0038] Figure 7 This is a diagram showing spherical aberration, astigmatism, and distortion during zoom in Example 2;

[0039] Figure 8 This is a diagram showing spherical aberration, astigmatism, and distortion at the telescope of Example 2;

[0040] Figure 9 This is a schematic diagram of the zoom lens structure in Embodiment 3;

[0041] Figure 10 This is a diagram showing spherical aberration, astigmatism, and distortion at the wide-angle end of Example 3;

[0042] Figure 11 This is a diagram showing spherical aberration, astigmatism, and distortion during zoom in Example 3;

[0043] Figure 12 This is a diagram showing spherical aberration, astigmatism, and distortion at the telescope of Example 3;

[0044] Figure 13 This is a schematic diagram of the zoom lens structure in Example 4;

[0045] Figure 14 This is a diagram showing spherical aberration, astigmatism, and distortion at the wide-angle end of Example 4;

[0046] Figure 15 This is a diagram showing spherical aberration, astigmatism, and distortion during zoom in Example 4;

[0047] Figure 16 This is a diagram showing spherical aberration, astigmatism, and distortion at the telescope in Example 4.

[0048] Label Explanation:

[0049] First lens group G1; Second lens group G2; Third lens group G3; Fourth lens group G4; Fifth lens group G5; Sixth lens group G6; Aperture stop S; Image plane IMG. Detailed Implementation

[0050] The large-aperture zoom lens and the photographic device using the zoom lens of this utility model will be described below with reference to the accompanying drawings.

[0051] This utility model discloses a large-aperture zoom lens. The lens has the shortest total length at the wide-angle end. During the zoom process towards the telephoto end, six lens groups are arranged sequentially from the object side: a first lens group G1 with positive optical power, a second lens group G2 with negative optical power, a third lens group G3 with positive optical power, a fourth lens group G4 with positive optical power, a fifth lens group G5 with negative optical power, and a sixth lens group G6 with optical power.

[0052] In this system, the first lens group G1 and the second lens group G2 are located on the object side of the aperture stop S, belonging to the front half-lens group. The third lens group G3 to the sixth lens group G6 are located on the image plane (IMG) side of the aperture stop S, belonging to the rear half-lens group. When the photographed object moves closer from infinity, the fifth lens group G5 moves from the object side towards the image plane side to achieve the focusing function.

[0053] The third lens group G3 consists of a lens L31 with positive optical power, a lens L32 with positive optical power, and a lens L33 with negative optical power, arranged sequentially from the object side to the image plane side. The spacing between lenses L32 and L33 is the widest in the third lens group G3. This configuration of the third lens group G3 effectively balances the aberrations of the front and rear lens groups, helps control the overall length of the lens, reduces the use of aspherical lenses, achieves a compact structure, and lowers costs. Furthermore, this invention uses a fifth lens group G5 as the focusing lens. The fifth lens group G5 is composed of one or two lenses, has a simple structure, is lightweight, and enables fast focusing.

[0054] In this invention, the surface of the lens facing the object is defined as the object-side surface, and the surface facing the image plane is defined as the image-side surface. In the third lens group G3, the object-side surface of lens L31 convexes towards the object side, and the image-side surface convexes towards the image plane side; and the third lens group G3 satisfies the following conditions:

[0055] (1) 0.2 <d32 / T3<0.6;

[0056] Where d32 is the interval between lenses L32 and L33 in the third lens group G3, and T3 is the total length of the third lens group G3. Lens L31 of the third lens group G3 satisfies the above conditions, which can effectively control the spherical aberration of the rear half lens group without increasing the total length of the lens or reducing the number of aspherical lenses used.

[0057] To balance the chromatic aberration between the various lens groups, thereby controlling the lens's chromatic aberration throughout the zoom process, the third lens group G3 also satisfies the following conditions:

[0058] (2)71 <vd31<96;

[0059] (3)1.0<(2-nd31)*200 / vd31<1.3;

[0060] (4)71 <vd32<96;

[0061] (5)1.0<(2-nd31)*200 / vd32<1.3;

[0062] Wherein, vd31 and nd31 are the d-line dispersion coefficient and d-line refractive index of lens L31 in the third lens group G3, respectively; vd32 and nd32 are the d-line dispersion coefficient and d-line refractive index of lens L32 in the third lens group G3, respectively.

[0063] Furthermore, the first lens group G1 of this invention includes a negative power lens L11 near the object side and a positive power lens L12 near the image plane side. The second lens group includes a negative power lens L21, a negative power lens L22, a positive power lens L23, and a lens L24 with negative power, arranged sequentially from the object side to the image plane side, wherein lens L22 and lens L23 constitute a combined lens.

[0064] The second lens group satisfies the following conditions:

[0065] (6)2.5 <f2e / f2<6.0;

[0066] Where f2e is the focal length of lens L24, and f2 is the focal length of the second lens group G2. By restricting the structure and parameters of the first lens group G1 and the second lens group G2, the spherical aberration of the front half lens group can be effectively controlled.

[0067] The first lens group G1 and the fourth lens group G4 satisfy the following conditions:

[0068] (7)3.0 <f1 / f4<7.0;

[0069] Here, f1 is the focal length of the first lens group G1, and f4 is the focal length of the fourth lens group G4. By setting the focal length parameters between the first lens group G1 and the fourth lens group G4, it is beneficial to balance the spherical aberration between the front and rear semi-lens groups without adding additional conditions, thereby facilitating the compactness of the overall lens structure and the control of overall cost.

[0070] The fifth lens group G5 and the sixth lens group G6 of this utility model satisfy the following conditions:

[0071] (8) 0.7 <frw / frt<1.2;

[0072] Where frw is the combined focal length of the fifth lens group G5 and the sixth lens group G6 at the wide-angle end, and frt is the combined focal length of the fifth lens group G5 and the sixth lens group G6 at the telephoto end. By setting the focal length parameters of the fifth lens group G5 and the sixth lens group G6 on its image plane side, the breathing effect during focusing can be reduced while ensuring close-range imaging performance.

[0073] This utility model also discloses a camera device, which includes a large-aperture zoom lens with the above-described structure, and an imaging element located on the image plane side of the zoom lens and converting the optical image formed by the zoom lens into an electrical signal.

[0074] To better illustrate the technical solution of this utility model, four embodiments of zoom lenses will be described below.

[0075] Example 1

[0076] like Figure 1 As shown, the large-aperture zoom lens in Embodiment 1 is configured with six lens groups, which, from the object side to the image plane side, are: a first lens group G1 with positive optical power, a second lens group G2 with negative optical power, a third lens group G3 with positive optical power, a fourth lens group G4 with positive optical power, a fifth lens group G5 with negative optical power, and a sixth lens group G6 with negative optical power. The first lens group G1 and the second lens group G2 are located on the object side of the aperture stop S, belonging to the front half-lens group. The third to sixth lens groups G3 are located on the image plane side of the aperture stop S, belonging to the rear half-lens group. When the photographed object moves closer from infinity, the fifth lens group G5 moves from the object side towards the image plane side, achieving the focusing function.

[0077] The first lens group G1 includes a negative power lens L11 near the object side and a positive power lens L12 near the image plane side. Lens L11 is a convex-concave lens, and lens L12 is a convex-concave lens. The second lens group G2 includes a negative power lens L21, a negative power lens L22, a positive power lens L23, and a lens L24 with negative power, arranged sequentially from the object side to the image plane side. Among them, lens L21 is a convex-concave lens, lens L22 is a biconcave lens, and lens L23 is a convex-concave lens. The image plane side of lens L22 is bonded to the object plane side of lens L23 to form a combined lens. Lens L24 is an aspherical lens, and both its object plane side and image plane side are aspherical.

[0078] The third lens group G3 consists of three lenses arranged sequentially from the object side to the image plane side: lens L31 with positive optical power, lens L32 with positive optical power, and lens L33 with negative optical power. The spacing between lenses L32 and L33 is the widest in the third lens group G3. Lens L31 is a biconvex lens, lens L32 is a convex-concave lens, and lens L33 is a concave-convex lens.

[0079] The fourth lens group G4 includes lens L41 and lens L42, both with positive optical power. Lens L41 is a biconvex lens, and lens L42 is an aspherical lens, with both its object-side and image-side surfaces being aspherical. The fifth lens group G5 includes lens L51, which has negative optical power and is a convex-concave lens. The sixth lens group G6 includes lens L61, which has positive optical power, and lens L62, which has negative optical power. Lens L61 is an aspherical lens, with both its object-side and image-side surfaces being aspherical, and lens L62 is a concave-convex lens.

[0080] The specific optical parameters of this embodiment are as follows:

[0081]

[0082]

[0083] Aspherical data

[0084]

[0085] Variable interval

[0086]

[0087]

Parameters

[0088]

[0089] [Conditional expression]

[0090]

[0091] Figure 2 This is a diagram showing spherical aberration (SA), astigmatism (AST), and distortion (DIST) at the wide-angle end of Example 1. Figure 3 This is a diagram showing spherical aberration, astigmatism, and distortion during the zoom phase in Example 1. Figure 4 This is a diagram showing spherical aberration, astigmatism, and distortion at the telescope end in Example 1. Figure 2-4 In the spherical aberration diagram, different colored lines represent spherical aberration curves for different wavelengths, with more concentrated lines indicating smaller spherical aberration. The red line represents a wavelength of 656.273 nm (C); the yellow line represents a wavelength of 587.562 nm (d); the green line represents a wavelength of 546.074 nm (e); the blue line represents a wavelength of 486.133 nm (F); and the purple line represents a wavelength of 435.834 nm (g). Figure 2-4 In the astigmatism diagram, the dashed line (T) represents the change in the position of the meridional focal plane with the field of view, and the solid line (S) represents the change in the position of the sagittal focal plane with the field of view. The separation of the meridional and sagittal focal planes directly reflects the magnitude of astigmatism. The explanation of these diagrams is also consistent in the following embodiments, so the above explanation will be omitted in subsequent embodiments.

[0092] As can be seen from the parameters above, the Fno in this embodiment is 2.920, indicating a lens with a large aperture. The zoom lens uses three aspherical lenses, effectively controlling manufacturing costs. Furthermore, the fifth lens group G5 is implemented using a single lens L51, enabling fast focusing and effectively controlling focusing artifacts during use. Figure 2-4 It can be seen that the optical performance of this embodiment is good.

[0093] Example 2

[0094] like Figure 5As shown, the large-aperture zoom lens in Embodiment 2 is configured with six lens groups, which, from the object side to the image plane side, are: a first lens group G1 with positive optical power, a second lens group G2 with negative optical power, a third lens group G3 with positive optical power, a fourth lens group G4 with positive optical power, a fifth lens group G5 with negative optical power, and a sixth lens group G6 with positive optical power. The first lens group G1 and the second lens group G2 are located on the object side of the aperture stop S, belonging to the front half-lens group. The third to sixth lens groups G3 are located on the image plane side of the aperture stop S, belonging to the rear half-lens group. When the photographed object moves closer from infinity, the fifth lens group G5 moves from the object side towards the image plane side, achieving the focusing function.

[0095] The first lens group G1 includes a negative power lens L11 near the object side and a positive power lens L12 near the image plane side. Lens L11 is a convex-concave lens, and lens L12 is a convex-concave lens. The second lens group G2 includes a negative power lens L21, a negative power lens L22, a positive power lens L23, and a lens L24 with negative power, arranged sequentially from the object side to the image plane side. Among them, lens L21 is a convex-concave lens, lens L22 is a biconcave lens, and lens L23 is a convex-concave lens. The image plane side of lens L22 is bonded to the object plane side of lens L23 to form a combined lens. Lens L24 is an aspherical lens, and both its object plane side and image plane side are aspherical.

[0096] The third lens group G3 consists of three lenses arranged sequentially from the object side to the image plane side: lens L31 with positive optical power, lens L32 with positive optical power, and lens L33 with negative optical power. The spacing between lenses L32 and L33 is the widest in the third lens group G3. Lens L31 is a biconvex lens, lens L32 is a biconvex lens, and lens L33 is a concave-convex lens.

[0097] The fourth lens group G4 includes lenses L41, L42, and L43, all with positive optical power. Lens L41 is a biconvex lens, lens L42 is a concave-convex lens, and lens L43 is an aspherical lens with aspherical object-side and image-side surfaces. The fifth lens group G5 includes lens L51 with positive optical power and lens L52 with negative optical power, where lens L51 is a convex-concave lens and lens L52 is a biconcave lens. The sixth lens group G6 includes lens L61 with positive optical power, lens L62 with negative optical power, and lens L63 with negative optical power, where lens L61 is a convex-concave lens, lens L62 is a convex-concave lens, and lens L63 is a concave-convex lens.

[0098] The specific optical parameters of this second embodiment are as follows:

[0099]

[0100]

[0101] Aspherical data

[0102]

[0103] Variable interval

[0104]

[0105]

Parameters

[0106]

[0107] [Conditional expression]

[0108]

[0109] Figure 6 This is a diagram showing spherical aberration (SA), astigmatism (AST), and distortion (DIST) at the wide-angle end of Example 2. Figure 7 This is a diagram showing spherical aberration, astigmatism, and distortion during the zoom in Example 2. Figure 8 This is a diagram showing spherical aberration, astigmatism, and distortion at the telescope end in Example 2.

[0110] As can be seen from the parameters above, the Fno in this embodiment is 2.920, indicating a lens with a large aperture. The zoom lens uses two aspherical lenses, effectively controlling manufacturing costs. Furthermore, the fifth lens group G5 is implemented using lenses L51 and L52, enabling fast focusing and effectively controlling focusing artifacts during use. Figure 6-8 It can be seen that the optical performance of this embodiment is good.

[0111] Example 3

[0112] like Figure 9 As shown, the large-aperture zoom lens in Embodiment 3 is configured with six lens groups, which, from the object side to the image plane side, are: a first lens group G1 with positive optical power, a second lens group G2 with negative optical power, a third lens group G3 with positive optical power, a fourth lens group G4 with positive optical power, a fifth lens group G5 with negative optical power, and a sixth lens group G6 with positive optical power. The first lens group G1 and the second lens group G2 are located on the object side of the aperture stop S, belonging to the front half-lens group. The third lens group G3 to the sixth lens group G6 are located on the image plane side of the aperture stop S, belonging to the rear half-lens group. When the photographed object moves closer from infinity, the fifth lens group G5 moves from the object side towards the image plane side, achieving the focusing function.

[0113] The first lens group G1 includes a negative power lens L11 near the object side and a positive power lens L12 near the image plane side. Lens L11 is a convex-concave lens, and lens L12 is a convex-concave lens. The second lens group G2 includes a negative power lens L21, a negative power lens L22, a positive power lens L23, and a lens L24 with negative power, arranged sequentially from the object side to the image plane side. Among them, lens L21 is a convex-concave lens, lens L22 is a biconcave lens, lens L23 is a convex-concave lens, and lens L24 is a concave-convex lens. The image plane side of lens L22 is bonded to the object side side of lens L23 to form a combined lens.

[0114] The third lens group G3 consists of three lenses arranged sequentially from the object side to the image plane side: lens L31 with positive optical power, lens L32 with positive optical power, and lens L33 with negative optical power. The spacing between lenses L32 and L33 is the widest in the third lens group G3. Lens L31 is a biconvex lens, lens L32 is a biconvex lens, and lens L33 is a concave-convex lens.

[0115] The fourth lens group G4 includes lenses L41 and L42, both with positive optical power. Lens L41 is a biconvex lens, and lens L42 is an aspherical lens, with both its object-side and image-side surfaces being aspherical. The fifth lens group G5 includes lens L51, which has negative optical power and is a convex-concave lens. The sixth lens group G6 includes lens L61, which has positive optical power, and lens L62, which has negative optical power. Lens L61 is a convex-concave lens, and lens L62 is a biconcave lens.

[0116] The specific optical parameters of this embodiment are as follows:

[0117]

[0118]

[0119] Aspherical data

[0120]

[0121] Variable interval

[0122]

[0123]

Parameters

[0124]

[0125] [Conditional expression]

[0126]

[0127] Figure 10The images show the spherical aberration (SA), astigmatism (AST), and distortion (DIST) at the wide-angle end of Example 3. Figure 11 This is a diagram showing spherical aberration, astigmatism, and distortion during the zoom in Example 3. Figure 12 This is a diagram showing spherical aberration, astigmatism, and distortion at the telescope end in Example 3.

[0128] As can be seen from the parameters above, the Fno in this embodiment is 2.920, indicating a lens with a large aperture. The zoom lens uses only one aspherical lens, effectively controlling manufacturing costs. Furthermore, the fifth lens group G5 is implemented using a single lens L51, enabling fast focusing and effectively controlling focusing artifacts during use. Figure 10-12 It can be seen that the optical performance of this embodiment is good.

[0129] Example 4

[0130] like Figure 13 As shown, the large-aperture zoom lens in Embodiment 4 is configured with six lens groups, which, from the object side to the image plane side, are: a first lens group G1 with positive optical power, a second lens group G2 with negative optical power, a third lens group G3 with positive optical power, a fourth lens group G4 with positive optical power, a fifth lens group G5 with negative optical power, and a sixth lens group G6 with negative optical power. The first lens group G1 and the second lens group G2 are located on the object side of the aperture stop S, belonging to the front half-lens group. The third to sixth lens groups G6 are located on the image plane side of the aperture stop S, belonging to the rear half-lens group. When the photographed object moves closer from infinity, the fifth lens group G5 moves from the object side towards the image plane side, achieving the focusing function.

[0131] The first lens group G1 includes a negative power lens L11 near the object side and a positive power lens L12 near the image plane side. Lens L11 is a convex-concave lens, and lens L12 is a convex-concave lens. The second lens group G2 includes, in sequence from the object side to the image plane side, a negative power lens L21, a negative power lens L22, a positive power lens L23, and a lens L24 with negative power. Lens L21 is a convex-concave lens, lens L22 is a biconcave lens, lens L23 is a convex-concave lens, and lens L24 is a concave-convex lens. Lens L22 and lens L23 form a combined lens, with the image plane side of lens L22 and the object plane side of lens L23 closely spaced (less than 1.0 mm).

[0132] The third lens group G3 consists of three lenses arranged sequentially from the object side to the image plane side: lens L31 with positive optical power, lens L32 with positive optical power, and lens L33 with negative optical power. The spacing between lenses L32 and L33 is the widest in the third lens group G3. Lens L31 is a biconvex lens, lens L32 is a convex-concave lens, and lens L33 is a concave-convex lens.

[0133] The fourth lens group G4 includes lens L41 with positive refractive power, lens L42 with negative refractive power, and lens L43. Lens L41 is a biconvex lens, lens L42 is a concave-convex lens, and lens L43 is an aspherical lens, with both the object-side and image-side surfaces of lens L43 being aspherical. The fifth lens group G5 includes lens L51 with positive optical power and lens L52 with negative optical power, where lens L51 is a concave-convex lens and lens L52 is a biconcave lens. The sixth lens group G6 includes lens L61 with positive optical power, lens L62 with negative optical power, and lens L63 with negative optical power, where lens L61 is a biconvex lens, lens L62 is a biconcave lens, and lens L63 is a concave-convex lens.

[0134] The specific optical parameters for this fourth embodiment are as follows:

[0135]

[0136]

[0137] Aspherical data

[0138]

[0139] Variable interval

[0140]

[0141]

Parameters

[0142]

[0143] [Conditional expression]

[0144]

[0145] Figure 14 The images show the spherical aberration (SA), astigmatism (AST), and distortion (DIST) at the wide-angle end of Example 4. Figure 15 This is a diagram showing spherical aberration, astigmatism, and distortion during the zoom in Example 4. Figure 16 This is a diagram showing spherical aberration, astigmatism, and distortion at the telescope in Example 4.

[0146] As can be seen from the parameters above, the Fno in this embodiment is 2.920, indicating a lens with a large aperture. The zoom lens uses only one aspherical lens, effectively controlling manufacturing costs. Furthermore, the fifth lens group G5 is implemented using lenses L51 and L52, enabling fast focusing and effectively controlling focusing artifacts during use. Figure 2-4 It can be seen that the optical performance of this embodiment is good.

[0147] The optical length, zoom ratio, and other parameters of the zoom lenses in Embodiments 1 to 4 described above are as follows:

[0148]

[0149] This invention features a large aperture and uses a simple fifth lens group as the focusing lens, enabling fast autofocus within its zoom range. Furthermore, the structural design of the third lens group G3 balances the aberration effects of the front and rear lens groups, helping to control the overall length of the lens, while reducing the use of aspherical lenses, achieving a compact structure and lowering costs.

[0150] The above description is merely an embodiment of the present utility model and does not constitute any limitation on the technical scope of the present utility model. Therefore, any minor modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model shall still fall within the scope of the technical solution of the present utility model.

Claims

1.A large-aperture zoom lens, the total length of the lens being shortest at a wide-angle end, the lens comprising, in order from an object side during zooming toward a telephoto end, six lens groups, which are a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having positive refractive power, a fifth lens group having negative refractive power, and a sixth lens group having refractive power, characterized in that: the first lens group and the second lens group are located on the object side of an aperture stop S and belong to a front half lens group; the third lens group to the sixth lens group are located on the image side of the aperture stop S and belong to a rear half lens group; when a photographic object approaches from infinity to a close distance, the fifth lens group moves from the object side toward the close image side to realize a focusing function; the third lens group comprises, in order from the object side toward the image side, a lens L31 having positive refractive power, a lens L32 having positive refractive power, and a lens L33 having negative refractive power; and the interval between the lens L32 and the lens L33 is widest in the third lens group; the object side surface of the lens L31 of the third lens group is convex toward the object side, and the image side surface of the lens L31 is convex toward the image side; and the third lens group satisfies the following condition: (1) 0.2 < d32 / T3 < 0.6; wherein d32 is the interval between the lens L32 and the lens L33 in the third lens group, and T3 is the total length of the third lens group; and the third lens group further satisfies the following conditions: (2) 71 < vd31 < 96; (3) 1.0 < (2-nd31) * 200 / vd31 < 1.3; (4) 71 < vd32 < 96; (5) 1.0 < (2-nd31) * 200 / vd32 < 1.3; wherein vd31 and nd31 are the d-line dispersion coefficient and the d-line refractive index of the lens L31 in the third lens group, respectively, and vd32 and nd32 are the d-line dispersion coefficient and the d-line refractive index of the lens L32 in the third lens group, respectively; the first lens group comprises a negative refractive power lens L11 close to the object side and a positive refractive power lens L12 close to the image side; the second lens group comprises, in order from the object side toward the image side, a negative refractive power lens L21, a negative refractive power lens L22, a positive refractive power lens L23, and a lens L24 having negative refractive power, wherein the lens L22 and the lens L23 constitute a combined lens; the second lens group satisfies the following condition: (6) 2.5 < f2e / f2 < 6.0; wherein f2e is the focal length of the lens L24, and f2 is the focal length of the second lens group; the first lens group and the second lens group satisfy the following condition: (7) 3.0 < f1 / f4 < 7.0; wherein f1 is the focal length of the first lens group, and f4 is the focal length of the fourth lens group; and the fifth lens group and the sixth lens group satisfy the following condition: (8) 0.7 < frw / frt < 1.2; wherein frw is the combined focal length of the fifth lens group G5 and the sixth lens group G6 at the wide-angle end, and frt is the combined focal length of the fifth lens group G5 and the sixth lens group G6 at the telephoto end. ​ ​ ​ 2. The large-aperture zoom lens according to claim 1, characterized by: ​ ​ ​ 3. The large-aperture zoom lens of claim 1, wherein: ​ ​ ​ ​ ​ ​ 4. The large-aperture zoom lens of claim 1, wherein: ​ 5. The large-aperture zoom lens of claim 1, wherein: ​ 6. The large-aperture zoom lens of claim 5, wherein: ​ ​ ​ 7. The large-aperture zoom lens of claim 1, wherein: ​ ​ ​ 8. The large-aperture zoom lens of claim 1, wherein: ​ ​ ​ 9. An image pickup device, characterized by comprising: The camera includes the large-aperture zoom lens according to any one of claims 1 to 8, and a camera element located on the image plane side of the zoom lens and converting an optical image formed by the zoom lens into an electric signal.

Images