Lens and photographic equipment

Abstract

The invention provides a lens and photographic equipment. The lens comprises a first lens group with negative focal power and a second lens group with positive focal power which are sequentially arranged from an object side to an image side, the first lens group comprises at least two lenses with positive focal power and at least two lenses with negative focal power; the second lens group comprises a front lens group with positive focal power, a diaphragm and a rear lens group with positive focal power which are sequentially arranged from the object side to the image side, and the second lens group can move along the optical axis direction relative to the first lens group so as to realize focusing under different object distances. According to the lens, various aberrations in the lens groups are corrected through respective lens arrangement of the first lens group and the second lens group, the overall resolving power of the lens is effectively improved, and the aberrations of an optical system under different object distances are effectively balanced through a focusing mode that the second lens group comprising the front lens group, the diaphragm and the rear lens group moves along the optical axis.

Description

Technical Field

[0001] This application pertains to the field of photography, and more specifically, relates to a lens and photographic equipment. Background Technology

[0002] With the development of electronic technology, photographic equipment is constantly being updated and replaced. From film cameras to digital cameras, from SLR cameras to mirrorless cameras, photography enthusiasts have more choices and possibilities. However, with the development of photographic equipment, the requirements for lenses also increase accordingly, and currently, lenses for photographic equipment are difficult to meet aberration requirements. Summary of the Invention

[0003] The purpose of this application is to provide a lens and photographic equipment to solve the technical problem that existing lenses cannot meet aberration requirements.

[0004] To achieve the above objectives, the technical solution adopted in this application is: to provide a lens, the lens comprising a first lens group having negative optical power and a second lens group having positive optical power arranged sequentially from the object side to the image side;

[0005] The first lens group includes at least two lenses with positive optical power and at least two lenses with negative optical power.

[0006] The second lens group includes a front lens group with positive optical power, an aperture, and a rear lens group with positive optical power arranged sequentially from the object side to the image side. The second lens group can move relative to the first lens group along the optical axis to achieve focusing at different object distances.

[0007] Optionally, the first lens group includes a first lens located closest to the object side of the first lens group. The first lens is a meniscus lens with negative optical power that bends towards the aperture stop, and the first lens satisfies the following:

[0008] -3.26≤f L1 / f≤-1.84

[0009] Among them, f L1 denoted by , where f represents the focal length of the first lens, and f represents the effective focal length of the lens when focused at infinity.

[0010] Optionally, at least one lens in the second lens group has an Abbe number Vd that satisfies: Vd≥68.3, and at least one lens in the second lens group has a refractive index nd that satisfies: nd≥1.92.

[0011] Optionally, the combined focal length of the front lens group and the combined focal length of the second lens group satisfy the following:

[0012] 1.41≤f G2A / f G2 ≤1.92

[0013] Among them, f G2A f represents the combined focal length of the front lens group. G2 This represents the combined focal length of the second lens group. Optionally, the combined focal length of the rear lens group and the combined focal length of the second lens group satisfy the following:

[0014] 1.53≤f G2B / f G2 ≤2.05

[0015] Among them, f G2B f represents the combined focal length of the rear lens group. G2 This indicates the combined focal length of the second lens group.

[0016] Optionally, the lengths of the first lens group and the second lens group in the optical axis direction satisfy the following:

[0017] 0.89≤TL G1 / TL G2 ≤1.05

[0018] Among them, TL G1 TL represents the length of the first lens group along the optical axis. G2 The length of the second lens group along the optical axis.

[0019] Alternatively, when the lens is focused at infinity, the lens's focal length, half field of view, and back focal length satisfy the following conditions:

[0020] 0.70≤BFL / (f*tanω)≤0.82

[0021] Where f represents the focal length of the lens, ω represents the half field of view of the lens, and BFL represents the back focal length of the lens.

[0022] Optionally, the first lens group includes a first lens with negative optical power, a second lens with negative optical power, a third lens with positive optical power, a fourth lens with negative optical power, and a fifth lens with positive optical power, arranged sequentially from the object side to the image side.

[0023] The front lens group includes a sixth lens with positive optical power and a seventh lens with negative optical power arranged sequentially from the object side to the image side;

[0024] The rear lens group includes an eighth lens with negative optical power, a ninth lens with positive optical power, a tenth lens with positive optical power, an eleventh lens with positive optical power, a twelfth lens with negative optical power, and a thirteenth lens with positive optical power, arranged sequentially from the object side to the image side.

[0025] Optionally, the first lens group includes a first lens with negative optical power, a second lens with negative optical power, a third lens with negative optical power, a fourth lens with positive optical power, a fifth lens with negative optical power, and a sixth lens with positive optical power, arranged sequentially from the object side to the image side.

[0026] The front lens group includes a seventh lens with positive optical power and an eighth lens with negative optical power arranged sequentially from the object side to the image side;

[0027] The rear lens group includes a ninth lens with negative optical power, a tenth lens with positive optical power, an eleventh lens with positive optical power, a twelfth lens with positive optical power, a thirteenth lens with negative optical power, and a fourteenth lens with positive optical power, arranged sequentially from the object side to the image side.

[0028] This application also provides a photographic apparatus that includes the lens described above.

[0029] The beneficial effects of the lens and photographic equipment provided in this application are as follows: Compared with the prior art, the lens in the embodiment of this application includes a first lens group with negative optical power and a second lens group with positive optical power. The first lens group includes at least two lenses with positive optical power and at least two lenses with negative optical power. The second lens group includes a front lens group with positive optical power, an aperture stop, and a rear lens group with positive optical power. By correcting various aberrations within the lens group through the respective lens arrangements of the first and second lens groups, the overall resolving power of the lens is effectively improved. Furthermore, by using a focusing method in which the second lens group, which includes the front lens group, the aperture stop, and the rear lens group, moves along the optical axis, the aberrations of the optical system at different object distances are effectively balanced. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a 2D structure diagram of the optical path of the lens at infinity focusing point in Example 1.

[0032] Figure 2 This is an axial aberration curve of the lens at infinity focus in Example 1.

[0033] Figure 3 The field curvature diagram of the lens at infinity focus in Example 1;

[0034] Figure 4This is a distortion curve of the lens at infinity focus in Example 1.

[0035] Figure 5 This is an axial aberration curve at the closest focusing point in Example 1;

[0036] Figure 6 This is the field curvature diagram at the closest focus point in Example 1;

[0037] Figure 7 This is a distortion curve diagram of Example 1 at the closest focus point;

[0038] Figure 8 This is a 2D diagram of the optical path structure of the lens at infinity focusing point in Example 2.

[0039] Figure 9 This is a graph showing the axial aberration of the lens at infinity focus in Example 2.

[0040] Figure 10 This is a field curvature diagram of the lens at infinity focus in Example 2;

[0041] Figure 11 This is a distortion curve of the lens at infinity focus in Example 2;

[0042] Figure 12 This is an axial aberration curve at the closest focusing point in Example 2;

[0043] Figure 13 This is the field curvature diagram at the closest focus point in Example 2;

[0044] Figure 14 This is a distortion curve diagram of the closest focusing point in Example 2;

[0045] Figure 15 This is a 2D structure diagram of the optical path of the lens at infinity focusing point in Example 3.

[0046] Figure 16 This is a graph showing the axial aberration curve of the lens at infinity focus in Example 3.

[0047] Figure 17 This is a field curvature diagram of the lens at infinity focus in Example 3;

[0048] Figure 18 This is a distortion curve of the lens at infinity focus in Example 3;

[0049] Figure 19 This is an axial aberration curve at the closest focusing point in Example 3;

[0050] Figure 20 This is the field curvature diagram at the closest focus point in Example 3;

[0051] Figure 21 This is a distortion curve diagram of the closest focus point in Example 3. Detailed Implementation

[0052] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0053] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0054] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0055] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0056] Photographic equipment is primarily used for taking photos or videos, including film cameras, SLR cameras, mirrorless cameras, and other similar devices. The lens is the core component of photographic equipment. A lens consists of multiple lenses, the shape and position of which determine its focal length and angle of view. When light passes through a lens, it undergoes refraction and reflection, changing its direction of propagation and allowing it to converge on the focal plane to form a clear image, which is then captured by the image sensor.

[0057] The evolution of photographic equipment has primarily progressed from DSLR cameras to mirrorless cameras. Compared to DSLRs, mirrorless cameras offer significant advantages in size, weight, autofocus, and functionality, catering to the needs of photographers of varying skill levels and abilities. Generally, to achieve excellent results in low-light conditions, photographers tend to favor lenses with larger apertures to ensure sufficient light intake. However, a larger aperture increases spherical aberration, coma, and axial chromatic aberration. Simultaneously, a wider field of view exacerbates coma, field curvature, and transverse chromatic aberration. To balance aberrations and improve optical performance, lens length and aperture are typically increased. However, with the miniaturization of mirrorless camera bodies, more stringent requirements have been placed on lens dimensions, making it difficult to simultaneously achieve large apertures while minimizing aberrations and balancing size.

[0058] In view of this, this application provides a lens comprising a first lens group having negative optical power and a second lens group having positive optical power arranged sequentially from the object side to the image side;

[0059] The first lens group includes at least two lenses with positive optical power and at least two lenses with negative optical power.

[0060] The second lens group includes a front lens group with positive optical power, an aperture, and a rear lens group with positive optical power arranged sequentially from the object side to the image side. The second lens group can move relative to the first lens group along the optical axis to achieve focusing at different object distances.

[0061] The object side of a lens refers to the side of the lens facing the subject, which is the initial side where light enters the lens. On this side, the lens receives light from the subject and guides it into the lens for refraction and focusing. The image side refers to the side of the lens where the image is formed after the light has been refracted and focused. On this side, the light is converged into a sharp image point, which is then captured and recorded by the imaging device. In this embodiment, the lens consists of a first lens group and a second lens group from the object side to the image side. The first lens group has negative optical power, and the second lens group has positive optical power. The optical power of both the first and second lens groups refers to the total optical power of the lenses they contain.

[0062] The first lens group comprises at least two lenses with positive optical power and at least two lenses with negative optical power, effectively correcting various aberrations such as spherical aberration, coma, and distortion within the first lens group, thus significantly improving the overall resolving power of the lens. The second lens group comprises a front lens group, an aperture stop, and a rear lens group arranged sequentially from the object side to the image side. The second lens group has positive optical power, and both the front and rear lens groups it contains also have positive optical power, further reducing aberrations in the second lens group. When an object moves from infinity on the object side towards the image side, the first lens group remains stationary relative to the image plane, while the second lens group moves along the optical axis from the image side towards the object side. This compensates for image plane displacement caused by changes in object distance, thereby achieving focus. Using this focusing method, aberrations of the optical system at different object distances can be effectively balanced, especially field curvature, thereby improving image quality at the closest focusing distance while maintaining a large aperture.

[0063] In summary, this embodiment, on the one hand, corrects various aberrations within the lens group by arranging the lenses of the first and second lens groups respectively, effectively improving the overall resolving power of the lens; on the other hand, by using a focusing method in which the second lens group, which includes a front lens group, an aperture stop, and a rear lens group, moves along the optical axis, it effectively balances the aberrations of the optical system at different object distances, enabling the lens of this embodiment to effectively balance aberrations while achieving a large aperture.

[0064] In some embodiments of this application, the first lens group includes a first lens located closest to the object side of the first lens group. The first lens is a meniscus lens with negative optical power that bends toward the aperture stop, and the first lens satisfies the following:

[0065] -3.26≤f L1 / f≤-1.84

[0066] Among them, f L1 denoted by , where f represents the focal length of the first lens, and f represents the effective focal length of the lens when focused at infinity.

[0067] The first lens is the lens closest to the object side in the first lens group, and it is also the first lens in the lens from the object side to the image side. External light rays first enter the first lens. The first lens is a meniscus lens; a meniscus structure means that one side of the lens is concave and the other side is convex, forming an overall shape similar to a crescent moon. The first lens is a meniscus lens that bends towards the aperture stop, meaning the concave surface of the first lens faces the aperture stop. The fact that the first lens is a meniscus lens with negative optical power and bends towards the aperture stop allows off-axis, large-angle field-of-view rays from a large-aperture wide-angle lens to enter the subsequent optical path at a gentler angle relative to the optical axis.

[0068] Additionally f L1The condition f satisfies the above equation, ensuring both optical performance and lens miniaturization. If this condition is below its lower limit, the negative optical power of the first lens weakens, reducing its ability to correct distortion aberrations. This makes compensation through the entire optical system difficult, and the lens front diameter increases, hindering miniaturization. Conversely, if the condition is above its upper limit, the negative optical power of the first lens strengthens, making distortion aberration correction easier, but also increasing spherical aberration, coma, and other aberrations, hindering overall lens optical performance. Therefore, the above equation for f... L1 The / f limit allows for the miniaturization of the lens while also addressing aberrations such as distortion, spherical aberration, and coma.

[0069] In some embodiments of this application, at least one lens in the second lens group has an Abbe number Vd that satisfies: Vd ≥ 68.3, and at least one lens in the second lens group has a refractive index nd that satisfies: nd ≥ 1.92. The Abbe number is also known as the dispersion coefficient; generally, the higher the Abbe number, the less dispersion the material exhibits. The refractive index of a lens refers to the lens material's ability to refract light. This embodiment effectively corrects chromatic aberration and improves image resolution and color reproduction through a reasonable combination of high-refractive-index glass and low-dispersion glass materials.

[0070] In some embodiments of this application, the combined focal length of the front lens group and the combined focal length of the second lens group satisfy the following:

[0071] 1.41≤f G2A / f G2 ≤1.92

[0072] Among them, f G2A f represents the combined focal length of the front lens group. G2 This indicates the combined focal length of the second lens group.

[0073] The combined focal length of the front lens group refers to the focal length exhibited by the individual lenses of the front lens group as a whole system. Similarly, the combined focal length of the second lens group refers to the focal length exhibited by the individual lenses of the second lens group as a whole system. G2A / f G2 Meeting the above condition can effectively suppress lens size while improving aberrations such as field curvature and distortion in a balanced way. If the condition is below its lower limit, the positive optical power of the front lens group becomes stronger, and aberrations such as spherical aberration or field curvature are difficult to correct well. If the condition is above its upper limit, the positive optical power of the front lens group becomes weaker, making it difficult to achieve a balance between field curvature and distortion with the rear lens group. In addition, the aperture of the rear lens group will become larger, which is not conducive to the realization of lens miniaturization.

[0074] In some embodiments of this application, the combined focal length of the rear lens group and the combined focal length of the second lens group satisfy the following:

[0075] 1.53≤f G2B / f G2 ≤2.05

[0076] Among them, f G2B f represents the combined focal length of the rear lens group. G2 This indicates the combined focal length of the second lens group.

[0077] The combined focal length of the rear lens group refers to the focal length exhibited by the combination of the individual lenses in the rear lens group as a whole system, f G2B / f G2 Meeting the above condition can effectively suppress lens size while improving aberrations such as axial chromatic aberration and field curvature in a balanced way. If the condition is below its lower limit, the optical power of the rear lens group becomes stronger, making it difficult to correct aberrations such as coma and field curvature while suppressing axial chromatic aberration; if the condition is above its upper limit, the optical power of the rear lens group becomes weaker, which will put a burden on the optical power of the front lens group, making it difficult to achieve the desired aberration correction effect.

[0078] In some embodiments of this application, the lengths of the first lens group and the second lens group in the optical axis direction satisfy the following:

[0079] 0.89≤TL G1 / TL G2 ≤1.05

[0080] Among them, TL G1 TL represents the length of the first lens group along the optical axis. G2 The length of the second lens group along the optical axis.

[0081] The aforementioned conditional expression specifies the ratio of the length of the first lens group in the optical axis to the length of the second lens group G2 in the optical axis. The length of the first lens group in the optical axis refers to the distance on the optical axis between the lens surface closest to the object side and the lens surface closest to the image side in the first lens group. The length of the second lens group in the optical axis refers to the distance on the optical axis between the lens surface closest to the object side and the lens surface closest to the image side in the second lens group. If the conditional expression is lower than its lower limit, the length of the first lens group in the optical axis becomes shorter, making it difficult to correct distortion aberrations. In addition, the length of the second lens group in the optical axis becomes relatively too long, increasing its weight load as a focusing group, which is not conducive to fast focusing. If the conditional expression is higher than its upper limit, the length of the first lens group in the optical axis becomes longer, making it easier to correct distortion aberrations. However, the length of the second lens group in the optical axis becomes relatively too short, making it more difficult to correct aberrations such as spherical aberration and coma, which is not conducive to improving the overall optical performance of the lens. Therefore, the lens of this embodiment can effectively correct the aberrations of the first and second lens groups while enabling the lens to focus quickly.

[0082] In some embodiments of this application, when the lens is focused at infinity, the focal length, half field of view, and back focal length of the lens satisfy the following:

[0083] 0.70≤BFL / (f*tanω)≤0.82

[0084] Where f represents the focal length of the lens, ω represents the half field of view of the lens, and BFL represents the back focal length of the lens.

[0085] The back focal length of a lens is the distance from the last optical surface of the lens to the focal plane, which is the distance from the image-side surface of the last lens element to the focal plane. The half-field of view is half the field of view, and is half the angle formed by the two edges of the maximum range through which the image of the target object can pass through the lens, with the lens as the vertex. The condition BFL / (f*tanω) satisfies the above condition to ensure the incident angle of the principal ray at the image plane in the off-axis field of view. If this condition is below its lower limit, the back focal length decreases, the incident angle of the principal ray in the off-axis field of view at the image plane increases, and the relative illumination will decrease; if this condition is above its upper limit, the back focal length increases, and the overall length of the lens also increases, which is not conducive to achieving lens miniaturization.

[0086] In some embodiments of this application, the first lens group includes a first lens with negative optical power, a second lens with negative optical power, a third lens with positive optical power, a fourth lens with negative optical power, and a fifth lens with positive optical power, arranged sequentially from the object side to the image side; the front lens group includes a sixth lens with positive optical power and a seventh lens with negative optical power, arranged sequentially from the object side to the image side; the rear lens group includes an eighth lens with negative optical power, a ninth lens with positive optical power, a tenth lens with positive optical power, an eleventh lens with positive optical power, a twelfth lens with negative optical power, and a thirteenth lens with positive optical power, arranged sequentially from the object side to the image side.

[0087] like Figure 1 and Figure 15 The illustrated embodiments all include thirteen lenses, numbered from L1 to L13 from the object side to the image side. Lenses L1 to L5 belong to the first lens group G1, L6 and L7 belong to the front lens group G2A of the second lens group G2, and L8 to L13 belong to the rear lens group G2B of the second lens group G2. The stop is located between the front lens group G2A and the rear lens group G2B. The second lens group G2 can move relative to the first lens group G1 to achieve focusing. This embodiment of the lens can effectively correct aberrations and reduce overall size while achieving a large aperture.

[0088] In some other embodiments of this application, the first lens group includes a first lens with negative optical power, a second lens with negative optical power, a third lens with negative optical power, a fourth lens with positive optical power, a fifth lens with negative optical power, and a sixth lens with positive optical power, arranged sequentially from the object side to the image side; the front lens group includes a seventh lens with positive optical power and an eighth lens with negative optical power, arranged sequentially from the object side to the image side; the rear lens group includes a ninth lens with negative optical power, a tenth lens with positive optical power, an eleventh lens with positive optical power, a twelfth lens with positive optical power, a thirteenth lens with negative optical power, and a fourteenth lens with positive optical power, arranged sequentially from the object side to the image side.

[0089] like Figure 8 The lens of the illustrated embodiment comprises fourteen lenses, numbered from L1 to L14 from the object side to the image side. Lenses L1 through L6 belong to the first lens group G1, lens L7 and lens L8 belong to the front lens group G2A of the second lens group G2, and lens L9 through L14 belong to the rear lens group G2B of the second lens group G2. The stop is located between the front lens group G2A and the rear lens group G2B. The second lens group G2 can move relative to the first lens group G1 to achieve focusing. This embodiment of the lens can effectively correct aberrations and reduce overall size while achieving a large aperture.

[0090] This application also provides a photographic apparatus that uses the lens described above. Specifically, the photographic apparatus can be a mirrorless camera, a DSLR camera, a mobile phone with photographic capabilities, or other electronic devices. The photographic apparatus of this embodiment can effectively balance aberrations while achieving a large aperture.

[0091] The present application will be further described below with reference to three embodiments.

[0092] The following are the data for the above conditional expressions corresponding to the three embodiments below:

[0093]

[0094]

[0095] Example 1:

[0096] like Figure 1 This is a 2D optical path diagram of the lens at infinity focusing point in Embodiment 1. From the object side to the image side, the lens sequentially includes a first lens group G1 with negative optical power, a second lens group G2 with positive optical power, and a protective glass CG. The second lens group G2 consists of a front lens group G2A with positive optical power, an aperture stop (STOP), and a rear lens group G2B with positive optical power.

[0097] When an object moves from infinity on the object side to the image side, in order to achieve focus, the first lens group G1 remains stationary relative to the image plane, while the second lens group G2 moves along the optical axis from the image side to the object side to compensate for the image plane displacement caused by the change in object distance.

[0098] The first lens group G1, from the object side to the image side, includes, in sequence, a first lens L1 with negative optical power and a meniscus structure, a second lens L2 with negative optical power and a meniscus structure, a third lens L3 with positive optical power and a biconvex structure, a fourth lens L4 with negative optical power and a plano-concave structure, and a fifth lens L5 with positive optical power and a biconvex structure.

[0099] The front lens group G2A includes, from the object side to the image side, a sixth lens L6 with positive optical power and a plano-convex structure, and a seventh lens L7 with negative optical power and a meniscus structure.

[0100] The rear lens group G2B, from the object side to the image side, includes, in sequence, an eighth lens L8 with negative optical power and a biconcave structure, a ninth lens L9 with positive optical power and a biconvex structure, a tenth lens L10 with positive optical power and a biconvex structure, an eleventh lens L11 with positive optical power and a biconvex structure, a twelfth lens L12 with negative optical power and a biconcave structure, and a thirteenth lens L13 with positive optical power and a meniscus structure. The eighth lens L8 and the ninth lens L9, as well as the eleventh lens L11 and the twelfth lens L12, are combined to form cemented lens groups, and the thirteenth lens L13 is an aspherical lens.

[0101] The surface data of each lens in the lens of Example 1 are as follows:

[0102] Face number Surface type R value thickness Refractive index Abbe number surface spherical flat D0 Page 1 spherical 56.36 2.40 1.73 54.68 Page 2 spherical 25.64 7.25 Page 3 spherical 109.74 1.97 1.59 68.34 Page 4 spherical 29.04 4.23 Page 5 spherical 102.97 3.76 1.92 20.88 Page 6 spherical -169.46 8.78 Page 7 spherical -27.38 2.80 1.92 23.96 8 spherical flat 0.15 9 spherical 212.43 4.69 1.95 32.28 10 spherical -35.71 D10 Page 11 spherical 24.74 5.04 1.70 55.53 12 spherical flat 0.15 Page 13 spherical 87.19 0.99 1.81 33.29 Page 14 spherical 39.99 3.66 aperture spherical flat 3.66 Page 16 spherical -25.31 1.00 1.85 25.15 Page 17 spherical 22.94 6.53 1.76 52.32 18 spherical -43.35 0.15 19 spherical 34.88 5.06 1.92 20.88 20 spherical -60.38 0.15 Page 21 spherical 26.65 7.55 1.59 68.34 22 spherical -23.81 0.99 1.85 25.15 Page 23 spherical 25.78 2.08 24 aspherical 80.34 2.40 1.85 40.10 25 aspherical 89.43 D25 Page 26 spherical flat 0.85 1.52 64.20 Page 27 spherical flat 0.5 Image spherical flat -

[0103] Variable spacing parameters for different object distances:

[0104] D0 (object distance) Infinity Closest focus point (0.4M) D10 (mm) 4.17 2.97 D25 (mm) 16.26 17.46

[0105] In this embodiment, the aspherical surface shape of the aspherical lens satisfies the following conditions:

[0106]

[0107] Where c is the curvature corresponding to the radius of curvature R, y is the radial coordinate (its unit is the same as the lens length unit), k is the conic coefficient (when the k coefficient is less than -1, the surface curve is a hyperbola; when the k coefficient is equal to -1, it is a parabola; when the k coefficient is between -1 and 0, it is an ellipse; when the k coefficient is equal to 0, it is a circle; and when the k coefficient is greater than 0, it is an oval), A4, A6, A8, A 10 A 12 A 14 A16 This refers to the aspheric coefficients of higher order terms. The definition of aspheric surface shape will not be repeated below.

[0108] The table below shows the conic coefficient and higher-order aspheric coefficients of the aspherical lens in Example 1.

[0109] The aspherical data are as follows:

[0110] Face number k A4 A6 A8 A10 24 0 1.21E-05 4.07E-08 -3.61E-09 2.29E-11 25 0 5.82E-05 -8.45E-09 -2.55E-09 1.56E-11

[0111] Face number A12 A14 A16 24 -4.18E-14 0 0 25 -2.86E-14 0 0

[0112] The optical parameters of the lens in Example 1 are as follows:

[0113] f Effective focal length (mm) when focusing at infinity 21.80 Fno aperture 1.45 w Half field of view (°) when focusing at infinity 45.79 H Half-image height (mm) 21.60 TTL Total optical length (mm) 97.22 BFL Back focal length (mm) when focusing at infinity 17.61 <![CDATA[f G1 ]]> Focal length of the first lens group (mm) -97.32 <![CDATA[f L1 ]]> Focal length (mm) of the lens closest to the object side in the first lens group. -66.44 <![CDATA[f G2 ]]> Focal length of the second lens group (mm) 30.66 <![CDATA[f G2A ]]> Front lens group focal length (mm) 53.56 <![CDATA[f G2B ]]> Rear lens group focal length (mm) 53.14 <![CDATA[TL G1 ]]> Length (mm) of the first lens group along the optical axis 36.03 <![CDATA[TL G2 ]]> Length (mm) of the second lens group along the optical axis 39.41

[0114] Figures 2-4 The diagram shown is the axial aberration curve, field curvature diagram, and distortion curve of the lens at infinity focus in Example 1. Figures 5-7 The figures shown are the axial aberration curve, field curvature curve, and distortion curve at the closest focusing point (0.4M) in Example 1. The axial aberration curve represents the axial aberration of the lens as the aperture changes. The three curves correspond to the axial aberrations at wavelengths of 0.486µm, 0.587µm, and 0.656µm, respectively. The horizontal axis represents the axial aberration value, and the vertical axis represents the normalized aperture. The field curvature curve represents the field curvature value of the lens as the field of view changes. The horizontal axis represents the field curvature magnitude, and the vertical axis represents the normalized field height. The solid line represents the meridional direction, and the dashed line represents the sagittal direction. The distortion curve represents the percentage distortion of the lens as the field of view changes. The horizontal axis represents the distortion percentage, and the vertical axis represents the normalized field height. The above descriptions of the axial aberration curve, field curvature curve, and distortion curve are the same as in other embodiments and will not be repeated below. Figures 2-4 and Figures 5-7 It can be seen that the lens of Example 1 has low axial aberration, field curvature and distortion, and excellent overall imaging.

[0115] Example 2:

[0116] like Figure 8 This is a 2D structural diagram of the optical path of the lens at infinity focusing point in Embodiment 2. From the object side to the image side, the lens sequentially includes a first lens group G1 with negative optical power, a second lens group G2 with positive optical power, and a protective glass CG. The second lens group G2 consists of a front lens group G2A with positive optical power, an aperture stop (STOP), and a rear lens group G2B with positive optical power.

[0117] When an object moves from infinity on the object side to the image side, in order to achieve focus, the first lens group G1 remains stationary relative to the image plane, while the second lens group G2 moves along the optical axis from the image side to the object side to compensate for the image plane displacement caused by the change in object distance.

[0118] The first lens group G1, from the object side to the image side, includes, in sequence, a first lens L1 with negative optical power and a meniscus structure, a second lens L2 with negative optical power and a meniscus structure, a third lens L3 with negative optical power and a meniscus structure, a fourth lens L4 with positive optical power and a biconvex structure, a fifth lens L5 with negative optical power and a biconcave structure, and a sixth lens L6 with positive optical power and a biconvex structure.

[0119] The front lens group G2A includes, from the object side to the image side, a seventh lens L7 with positive optical power and a plano-convex structure, and an eighth lens L8 with negative optical power and a meniscus structure.

[0120] The rear lens group G2B, from the object side to the image side, includes, in sequence, a ninth lens L9 with negative optical power and a biconcave structure, a tenth lens L10 with positive optical power and a biconvex structure, an eleventh lens L11 with positive optical power and a biconvex structure, a twelfth lens L12 with positive optical power and a biconvex structure, a thirteenth lens L13 with negative optical power and a biconcave structure, and a fourteenth lens L14 with positive optical power and a meniscus structure. Among these, the ninth lens L9 and the tenth lens L10, and the twelfth lens L12 and the thirteenth lens L13, are combined to form cemented lens groups, and the fourteenth lens L14 is an aspherical lens.

[0121] The surface data of each lens in the lens of Example 2 are as follows:

[0122]

[0123]

[0124] The variable spacing parameters for different object distances are as follows:

[0125] D0 (object distance) Infinity Closest focus point (0.4M) D12 (mm) 2.16 0.99 D27(mm) 16.28 17.45

[0126] The table below shows the conic coefficient and higher-order aspheric coefficients of the aspherical lens in Example 2.

[0127] The aspherical data are as follows:

[0128] Face number k A4 A6 A8 A10 26 0 -1.57E-06 -9.28E-08 -1.79E-09 1.54E-11 27 0 4.60E-05 -1.76E-07 -4.49E-10 8.50E-12

[0129] Face number A12 A14 A16 26 -2.66E-14 0 0 27 -1.94E-14 0 0

[0130] The optical parameters of the lens in Example 2 are as follows:

[0131] f Effective focal length (mm) when focusing at infinity 21.81 Fno aperture 1.45 w Half field of view (°) when focusing at infinity 45.02 H Half-image height (mm) 21.60 TTL Total optical length (mm) 97.77 BFL Back focal length (mm) when focusing at infinity 17.63 <![CDATA[f G1 ]]> Focal length of the first lens group (mm) -113.34 <![CDATA[f L1 ]]> Focal length (mm) of the lens closest to the object side in the first lens group. -57.70 <![CDATA[f G2 ]]> Focal length of the second lens group (mm) 31.22 <![CDATA[f G2A ]]> Front lens group focal length (mm) 57.79 <![CDATA[f G2B ]]> Rear lens group focal length (mm) 50.57 <![CDATA[TL G1 ]]> Length (mm) of the first lens group along the optical axis 37.19 <![CDATA[TL G2 ]]> Length (mm) of the second lens group along the optical axis 38.79

[0132] Figures 9-11 The diagram shows the axial aberration curve, field curve, and distortion curve at the infinity focus point in Example 2. Figures 12-14 The figures shown are the axial aberration curve, field curvature curve, and distortion curve at the closest focusing point (0.4M) in Example 2. From... Figures 9-11 and Figures 12-14 It can be seen that the lens of Embodiment 2 has lower axial aberration, field curvature and distortion, and excellent overall imaging.

[0133] Example 3:

[0134] like Figure 15 This is a 2D structural diagram of the optical path of the lens at infinity focusing point in Embodiment 3. From the object side to the image side, the lens sequentially includes a first lens group G1 with negative optical power, a second lens group G2 with positive optical power, and a protective glass CG. The second lens group G2 consists of a front lens group G2A with positive optical power, an aperture stop (STOP), and a rear lens group G2B with positive optical power.

[0135] When an object moves from infinity on the object side to the image side, in order to achieve focus, the first lens group G1 remains stationary relative to the image plane, while the second lens group G2 moves along the optical axis from the image side to the object side to compensate for the image plane displacement caused by the change in object distance.

[0136] The first lens group G1, from the object side to the image side, includes, in sequence, a first lens L1 with negative optical power and a meniscus structure, a second lens L2 with negative optical power and a meniscus structure, a third lens L3 with positive optical power and a plano-convex structure, a fourth lens L4 with negative optical power and a meniscus structure, and a fifth lens L5 with positive optical power and a meniscus structure. The second lens L2 is an aspherical lens.

[0137] The front lens group G2A includes, from the object side to the image side, a sixth lens L6 with positive optical power and a plano-convex structure, and a seventh lens L7 with negative optical power and a meniscus structure.

[0138] The rear lens group G2B, from the object side to the image side, includes, in sequence, an eighth lens L8 with negative optical power and a biconcave structure, a ninth lens L9 with positive optical power and a biconvex structure, a tenth lens L10 with positive optical power and a biconvex structure, an eleventh lens L11 with positive optical power and a biconvex structure, a twelfth lens L12 with negative optical power and a biconcave structure, and a thirteenth lens L13 with positive optical power and a meniscus structure. The eighth lens L8 and the ninth lens L9, as well as the eleventh lens L11 and the twelfth lens L12, are combined to form cemented lens groups, and the thirteenth lens L13 is an aspherical lens.

[0139] The surface data of each lens in the lens of Example 3 are as follows:

[0140]

[0141]

[0142] Variable spacing parameters for different object distances:

[0143] D0 (object distance) Infinity Closest focus point (0.4M) D10 (mm) 3.47 2.34 D25 (mm) 14.54 15.67

[0144] The table below shows the conic coefficient and higher-order aspheric coefficients of the aspherical lens in Example 3.

[0145] Aspherical data are as follows

[0146] Face number k A4 A6 A8 A10 3 16.41 -8.55E-07 9.17E-09 -1.65E-10 4.78E-13 4 2.99 -9.39E-06 -8.30E-09 -2.53E-10 6.72E-13 24 0 -6.21E-05 1.69E-07 -2.93E-09 3.28E-11 25 0 -1.31E-05 7.99E-08 2.18E-12 8.04E-12

[0147] Face number A12 A14 A16 3 -8.45E-16 0 0 4 -1.64E-15 0 0 24 -1.18E-13 0 0 25 -3.73E-14 0 0

[0148] The optical parameters of the lens in Example 3 are as follows:

[0149] f Effective focal length (mm) when focusing at infinity 21.77 Fno aperture 1.45 w Half field of view (°) when focusing at infinity 45.65 H Half-image height (mm) 21.60 TTL Total optical length (mm) 96.04 BFL Back focal length (mm) when focusing at infinity 15.89 <![CDATA[f G1 ]]> Focal length of the first lens group (mm) -674.22 <![CDATA[f L1 ]]> Focal length (mm) of the lens closest to the object side in the first lens group. -41.93 <![CDATA[f G2 ]]> Focal length of the second lens group (mm) 36.58 <![CDATA[f G2A ]]> Front lens group focal length (mm) 54.35 <![CDATA[f G2B ]]> Rear lens group focal length (mm) 72.37 <![CDATA[TL G1 ]]> Length (mm) of the first lens group along the optical axis 38.28 <![CDATA[TL G2 ]]> Length (mm) of the second lens group along the optical axis 38.40

[0150] Figures 16-18 The diagram shows the axial aberration curve, field curve, and distortion curve at the infinity focus point in Example 3. Figures 19-21 The figures shown are the axial aberration curve, field curvature curve, and distortion curve at the closest focusing point (0.4M) in Example 3. From... Figures 16-18 and Figures 19-21 It can be seen that the lens of Example 3 has low axial aberration, field curvature and distortion, and excellent overall imaging.

[0151] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A lens characterized by, The lens comprises, in order from the object side to the image side, a first lens group with negative focal power and a second lens group with positive focal power; The first lens group comprises at least two lenses with positive focal power and at least two lenses with negative focal power; The second lens group comprises, in order from the object side to the image side, a front lens group with positive focal power, a diaphragm and a rear lens group with positive focal power, and the second lens group is movable relative to the first lens group along the optical axis to achieve focusing at different object distances.

2. The lens of claim 1, wherein The first lens group comprises a first lens located closest to the object side of the first lens group, the first lens is a meniscus lens with negative focal power and curved towards the diaphragm, and the first lens satisfies: -3.26 < f L1 f < -1.84 wherein f L1 represents the focal length value of the first lens, and f represents the effective focal length value when the lens focuses at infinity.

3. The lens of claim 1, wherein The Abbe number Vd of at least one lens of the second lens group satisfies: Vd≥68.3, and the refractive index nd of at least one lens of the second lens group satisfies: nd≥1.

92.

4. The lens of claim 1, wherein The combined focal length of the front lens group and the combined focal length of the second lens group satisfy: 1.41 < f G2A / f G2 ≤ 1.92 wherein f G2A represents a combined focal length of the first lens group, f G2 represents a combined focal length of the second lens group.

5. The lens of claim 1, wherein The combined focal length of the rear lens group and the combined focal length of the second lens group satisfy: 1.53 < f G2B / f G2 ≤ 2.05 wherein f G2B represents a combined focal length of the rear lens group, f G2 represents a combined focal length of the second lens group.

6. The lens of claim 1, wherein The length of the first lens group in the optical axis direction and the length of the second lens group in the optical axis direction satisfy: 0.89 < TL G1 / TL G2 ≤ 1.05 TL G1 represents a length of the first lens group in the optical axis direction, TL G2 represents a length of the second lens group in the optical axis direction.

7. The lens of claim 1, wherein Under the condition that the lens focuses at infinity, the focal length, half field angle and back focal length of the lens satisfy: 0.70≤BFL / (f*tanω)≤0.82 Wherein, f represents the focal length of the lens, ω represents the half field angle of the lens, and BFL represents the back focal length of the lens.

8. The lens of any one of claims 1-7, wherein, The first lens group comprises, in order from the object side to the image side, a first lens with negative focal power, a second lens with negative focal power, a third lens with positive focal power, a fourth lens with negative focal power and a fifth lens with positive focal power; The front lens group comprises, in order from the object side to the image side, a sixth lens with positive focal power and a seventh lens with negative focal power; The rear lens group comprises, in order from the object side to the image side, an eighth lens with negative focal power, a ninth lens with positive focal power, a tenth lens with positive focal power, an eleventh lens with positive focal power, a twelfth lens with negative focal power and a thirteenth lens with positive focal power.

9. The lens of any one of claims 1-7, wherein, The first lens group comprises, in order from the object side to the image side, a first lens with negative focal power, a second lens with negative focal power, a third lens with negative focal power, a fourth lens with positive focal power, a fifth lens with negative focal power and a sixth lens with positive focal power; The front lens group comprises, in order from the object side to the image side, a seventh lens with positive focal power and an eighth lens with negative focal power; The rear lens group comprises, in order from the object side to the image side, a ninth lens with negative focal power, a tenth lens with positive focal power, an eleventh lens with positive focal power, a twelfth lens with positive focal power, a thirteenth lens with negative focal power and a fourteenth lens with positive focal power.

10. A photographic apparatus characterized by comprising: The photographic equipment comprises the lens according to any one of claims 1-9.

Images