Lens and photographic equipment

Abstract

The invention provides a lens and photographic equipment, the lens comprises a first lens group with positive focal power, a second lens group with positive focal power, a diaphragm and a third lens group with positive focal power from an object side to an image side, and the second lens group, the diaphragm and the third lens group can move by the same displacement relative to the first lens group along an optical axis direction. The focusing device is used for realizing focusing under different object distances; at least part of the lens between the object side and the diaphragm and at least part of the lens between the diaphragm and the image side form a double-Gaussian structure. According to the lens provided by the invention, the focusing requirement can be met, the aberration of the lens can be comprehensively reduced, the overall performance of the lens is improved, and the improvement effect is particularly obvious for a large-light-circle prime lens which is easy to generate large aberration.

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 as follows: a lens is provided, which includes a first lens group with positive optical power, a second lens group with positive optical power, an aperture stop, and a third lens group with positive optical power in the direction from the object side to the image side. The second lens group, the aperture stop, and the third lens group can be moved by the same amount of displacement relative to the first lens group along the optical axis to achieve focusing at different object distances. At least a portion of the lenses between the object side and the aperture stop and at least a portion of the lenses between the aperture stop and the image side form a double Gaussian structure.

[0005] Optionally, the lens from the object side to the aperture stop includes, in the direction from the object side to the image side, a negative optical power lens, a positive optical power lens, a positive optical power lens, and a negative optical power lens, and the lens from the aperture stop to the image side includes, in the same order, a negative optical power lens, a negative optical power lens, a positive optical power lens, a positive optical power lens, and a negative optical power lens.

[0006] Optionally, the first lens group includes a first lens with negative optical power and a second lens with positive optical power in sequence from the object side to the image side. The first lens has a biconcave structure and the second lens has a biconvex structure.

[0007] The second lens group includes, from the object side to the image side, a third lens with positive optical power and a fourth lens with negative optical power. The third lens has a biconvex structure and the fourth lens has a biconcave structure.

[0008] The third lens group includes a fifth lens with negative optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, an eighth lens with positive optical power, and a ninth lens with negative optical power. The fifth lens has a meniscus structure, the sixth lens has a biconcave structure, the seventh lens has a biconvex structure, the eighth lens has a biconvex structure, and the ninth lens has a biconcave structure.

[0009] Optionally, the third lens and the fourth lens are combined to form a cemented lens group, wherein the third lens group includes at least one cemented lens group consisting of a positive power lens and a negative power lens.

[0010] Optionally, the fifth lens is a molded glass aspherical lens.

[0011] Alternatively, when the lens is focused at infinity, the focal length of the first lens and the effective focal length of the lens satisfy the following:

[0012] -1.35≤f / f G1 ≤-0.78

[0013] Where f represents the effective focal length of the lens, f G1 This indicates the focal length of the first lens.

[0014] Optionally, the refractive index of the second lens satisfies:

[0015] nd≥2.00

[0016] Where nd represents the refractive index of the second lens.

[0017] Optionally, when the lens is focused at infinity, the combined focal length of the second lens group and the effective focal length of the lens satisfy the following:

[0018] 0.29≤f / f s2 ≤0.46

[0019] Where f represents the effective focal length of the lens, f s2 This indicates the combined focal length of the second lens group.

[0020] Optionally, the length of the third lens group along the optical axis and the combined focal length of the third lens group satisfy the following:

[0021] 0.41≤TL3 / f s3 ≤0.45

[0022] Where TL3 represents the length of the third lens group along the optical axis, f s3 This indicates the combined focal length of the third lens group.

[0023] Alternatively, when the lens is focused at infinity, the total optical length of the lens and the effective focal length of the lens satisfy the following:

[0024] TTL / f≤1.88

[0025] Where TTL represents the total optical length, and f represents the effective focal length of the lens.

[0026] Alternatively, when the lens is focused at infinity, the lens's back focal length, half field of view, and effective focal length values ​​satisfy the following:

[0027] 0.89≤BFL / (f*tan w)≤0.96

[0028] Where BFL represents the back focal length of the lens, w represents the half field of view of the lens, and f represents the effective focal length of the lens.

[0029] This application discloses a photographic apparatus that uses the lens described above.

[0030] The beneficial effects of the lens and photographic equipment provided in this application are as follows: Compared with the prior art, the lens of this application includes a first lens group with positive optical power, a second lens group with positive optical power, an aperture stop, and a third lens group with positive optical power from the object side to the image side. Not only can the second lens group, the aperture stop, and the third lens group move the same distance relative to the first lens group S1 along the optical axis to meet the focusing requirements, but also, on the one hand, the field curvature is reduced through the focusing structure, and on the other hand, various aberrations such as spherical aberration, coma, distortion, and chromatic aberration are effectively reduced by forming a double Gaussian architecture on both sides of the aperture stop STOP through at least some lenses. This more comprehensively reduces the aberrations of the lens and improves the overall performance of the lens, especially for large aperture prime lenses that are prone to large aberrations. Attached Figure Description

[0031] 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.

[0032] Figure 1 This is a 2D structural diagram of the optical path in Embodiment 1;

[0033] Figure 2 This is an axial aberration curve at infinity in Example 1;

[0034] Figure 3 This is the field curvature diagram at infinity in Example 1;

[0035] Figure 4 This is a distortion curve at infinity in Example 1;

[0036] Figure 5 This is an axial aberration curve at the closest focus point in Example 1;

[0037] Figure 6 This is the field curvature diagram of the closest focusing point in Example 1;

[0038] Figure 7 This is a distortion curve diagram of the closest focusing point in Example 1;

[0039] Figure 8 This is a 2D structural diagram of the optical path in Example 2;

[0040] Figure 9 This is an axial aberration curve at infinity in Example 2;

[0041] Figure 10 This is the field curvature diagram at infinity in Example 2;

[0042] Figure 11 This is a distortion curve at infinity in Example 2;

[0043] Figure 12 This is an axial aberration curve at the closest focusing point in Example 2;

[0044] Figure 13 This is the field curvature diagram of the closest focusing point in Example 2;

[0045] Figure 14 This is a distortion curve diagram of the closest focusing point in Example 2;

[0046] Figure 15 This is a 2D structural diagram of the optical path in Example 3;

[0047] Figure 16 This is the axial aberration curve at infinity in Example 3;

[0048] Figure 17 This is the field curvature diagram at infinity in Example 3;

[0049] Figure 18 This is a distortion curve at infinity in Example 3;

[0050] Figure 19 This is an axial aberration curve at the closest focusing point in Example 3;

[0051] Figure 20 This is the field curvature diagram of the closest focusing point in Example 3;

[0052] Figure 21 This is a distortion curve diagram of the closest focusing point in Example 3.

[0053] Reference numerals: First lens group S1, Second lens group S2, Stop stop, Third lens group S3, Protective glass CG, First lens G1, Second lens G2, Third lens G3, Fourth lens G4, Fifth lens G5, Sixth lens G6, Seventh lens G7, Eighth lens G8, Ninth lens G9. Detailed Implementation

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] The evolution of photographic equipment has primarily shifted from DSLR cameras to mirrorless cameras. Compared to DSLRs, mirrorless cameras offer significant advantages in terms of size, weight, autofocus, and functionality, catering to the needs of photographers of varying skill levels. Simultaneously, the design requirements for lenses used with mirrorless cameras have also changed. Lenses must be miniaturized while maintaining image quality. Given the constraints of size and weight, the aberration correction requirements for lenses suitable for mirrorless cameras are undoubtedly more stringent.

[0060] Please see Figure 1The lens provided in the embodiments of this application will now be described. The lens includes a first lens group S1 with positive optical power, a second lens group S2 with positive optical power, an aperture stop STOP, and a third lens group S3 with positive optical power from the object side to the image side. The second lens group S2, the aperture stop STOP, and the third lens group S3 can be moved by the same amount of displacement relative to the first lens group S1 along the optical axis to achieve focusing at different object distances. At least a portion of the lens between the object side and the aperture stop STOP and at least a portion of the lens between the aperture stop STOP and the image side form a double Gaussian structure.

[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 is refracted and focused. On this side, the light is converged into a sharp image point, which is ultimately captured and recorded by the imaging device. The lens of this application includes a first lens group S1, a second lens group S2, and a third lens group S3. Each lens group may include one or more lenses. The aperture stop STOP, which limits the light, is located between the second lens group S2 and the third lens group S3. Furthermore, a protective glass CG may be provided on the image side of the lens.

[0062] The second lens group S2, the aperture stop STOP, and the third lens group S3 can be moved the same distance relative to the first lens group S1 along the optical axis to achieve focusing at different object distances. Specifically, the second lens group S2, the aperture stop STOP, and the third lens group S3 can be set as a floating unit, or they can be moved separately, but each requires a certain amount of displacement. When focusing is needed, moving all three by the same amount compensates for the image plane shift caused by changes in object distance, thus achieving focusing at different object distances. Using this focusing method, field curvature at different focusing distances can be better corrected, ensuring high image quality while achieving focusing from infinity to the closest distance. Based on this focusing structure, at least a portion of the lenses between the object side and the stop, and at least a portion of the lenses between the stop and the image side, form a double Gaussian structure. For example, the double Gaussian structure can be formed by a portion of the lenses between the object side and the stop, and a portion of the lenses between the stop and the image side, or by all the lenses between the object side and the stop, and a portion of the lenses between the stop and the image side. Through the double Gaussian structure, in addition to achieving a large aperture, various aberrations such as spherical aberration, coma, distortion, and chromatic aberration can be effectively reduced.

[0063] Therefore, the lens in this embodiment not only meets the focusing requirements, but also reduces field curvature through the focusing structure, and effectively reduces various aberrations such as spherical aberration, coma, distortion, and chromatic aberration by forming a double Gaussian architecture on both sides of the stop aperture through at least some lenses. This more comprehensively reduces lens aberrations and improves the overall performance of the lens, especially for large aperture prime lenses that are prone to large aberrations.

[0064] Please see Figure 1 In one embodiment of this application, the lens arrangement from the object side to the stop (STOP) sequentially includes a negative power lens, a positive power lens, a positive power lens, and a negative power lens in the direction from the object side to the image side. The lens arrangement from the stop (STOP) to the image side sequentially includes a negative power lens, a negative power lens, a positive power lens, a positive power lens, and a negative power lens in the same order. A typical double-Gaussian lens arrangement can effectively correct various aberrations such as spherical aberration, coma, distortion, and chromatic aberration for lenses with moderate apertures, exhibiting strong applicability. However, for standard lenses with larger apertures, the increase in aperture leads to a sharp increase in aberrations such as spherical aberration and chromatic aberration. The lens arrangement in this embodiment is a further design based on the double-Gaussian lens arrangement, which can more effectively reduce various aberrations such as spherical aberration, coma, distortion, and chromatic aberration. For example, for a standard lens with a field of view between 40° and 60°, a common double Gaussian architecture is sufficient when the F-number is around 2.8. However, for a large aperture lens with an F-number between 1.4 and 2.0, a common double Gaussian architecture is difficult to meet the requirements. The lens arrangement method in this embodiment can more effectively reduce aberrations and improve imaging performance.

[0065] Please see Figure 1 In one embodiment of this application, the first lens group S1 includes, from the object side to the image side, a first lens G1 with negative optical power and a second lens G2 with positive optical power. The first lens G1 has a biconcave structure, and the second lens G2 has a biconvex structure. The second lens group S2 includes, from the object side to the image side, a third lens G3 with positive optical power and a fourth lens G4 with negative optical power. The third lens G3 has a biconvex structure, and the fourth lens G4 has a biconcave structure. The third lens group S3 includes a fifth lens G5 with negative optical power, a sixth lens G6 with negative optical power, a seventh lens G7 with positive optical power, an eighth lens G8 with positive optical power, and a ninth lens G9 with negative optical power. The fifth lens G5 has a meniscus structure, the sixth lens G6 has a biconcave structure, the seventh lens G7 has a biconvex structure, the eighth lens G8 has a biconvex structure, and the ninth lens G9 has a biconcave structure.

[0066] The first lens group S1 and the second lens group S2 are located between the object side of the lens and the aperture stop STOP. A first lens G1 with negative optical power, a second lens G2 with positive optical power, a third lens G3 with positive optical power, and a fourth lens G4 with negative optical power are arranged in sequence. The third lens group S3 is located between the aperture stop STOP and the image side of the lens. A fifth lens G5 with negative optical power, a sixth lens G6 with negative optical power, a seventh lens G7 with positive optical power, an eighth lens G8 with positive optical power, and a ninth lens G9 with negative optical power are arranged in sequence, forming a more complex double Gaussian structure on both sides of the aperture stop STOP. Among them, the first lens G1, the fourth lens G4, the sixth lens G6, and the ninth lens G9 are all biconcave structures, which means that the surfaces on both sides of the lens are concave curved surfaces. The second lens G2, the third lens G3, the seventh lens G7, and the eighth lens G8 are all biconvex structures, which means that the surfaces on both sides of the lens are convex curved surfaces. The fifth lens G5 is located on the side of the stop closer to the image side. It is a meniscus structure, which means that one side of the lens is a concave curved surface and the other side is a convex curved surface, forming an overall shape similar to a crescent moon.

[0067] In one embodiment of this application, the third lens G3 and the fourth lens G4 are combined to form a cemented lens group. The third lens group S3 includes at least one cemented lens group composed of a positive power lens and a negative power lens. The third lens G3 and the fourth lens G4 belong to the second lens group S2 and are located on the side of the aperture stop closer to the object side. The third lens group S3 is located on the side of the aperture stop closer to the image side. The second lens group S2, the aperture stop, and the third lens group S3 move by the same amount of displacement during focusing. By setting both the second lens group S2 and the third lens group S3, which move by the same amount of displacement during focusing, as cemented lens groups, chromatic aberration can be reasonably corrected, while the incident angle of light can be reduced, the tolerance sensitivity of the optical system can be reduced, and the overall imaging quality of the optical system can be effectively improved.

[0068] In one embodiment of this application, the fifth lens G5 is a molded glass aspherical lens. The fifth lens G5 is located on the side of the stop closer to the image side. Using an aspherical lens can effectively reduce the aberrations of the optical system, especially spherical aberration, and also facilitates the compression of the lens size. Compared with plastic aspherical lenses, glass aspherical lenses can increase the lens transmittance, thereby improving the image quality performance of the lens in low-light environments.

[0069] In one embodiment of this application, when the lens is focused at infinity, the focal length of the first lens G1 and the effective focal length of the lens satisfy the following:

[0070] -1.35≤f / f G1 ≤-0.78

[0071] Where f represents the effective focal length of the lens, fG1 This indicates the focal length of the first lens G1.

[0072] The effective focal length of a lens refers to the actual focal length that the lens can achieve during use, which can also be understood as the distance from the center of the lens to the actual imaging plane. In this embodiment, lens focusing still utilizes the same displacement between the second lens group S2, the aperture stop STOP, and the third lens group S3. When focusing at infinity, f / f... G1 Satisfying the above condition allows light rays with a wide field of view to pass through the subsequent lens group of the first lens G1 at a gentle angle. If the condition is lower than its lower limit, the absolute value of the negative optical power of the first lens G1 increases, the off-axis aberration will increase, which is not conducive to aberration balance. At the same time, the aperture of the front lens will also increase, which is not conducive to compressing the lens size. If the condition is higher than its upper limit, the absolute value of the negative optical power of the first lens G1 decreases, which will weaken the distortion correction capability.

[0073] In one embodiment of this application, the refractive index of the second lens G2 satisfies: nd ≥ 2.00, where nd represents the refractive index of the second lens G2. In this embodiment, the refractive index of the second lens G2 is greater than or equal to 2.00, which can effectively reduce the lens length while ensuring optical performance.

[0074] In one embodiment of this application, when the lens is focused at infinity, the combined focal length of the second lens group S2 and the effective focal length of the lens satisfy the following:

[0075] 0.29≤f / f s2 ≤0.46

[0076] Where f represents the effective focal length of the lens, f s2 This represents the combined focal length of the second lens group S2.

[0077] The combined focal length of a lens group refers to the distance from the optical center of the entire lens group to its common focal point. If f / f s2 Below its lower limit, the absolute value of the positive optical power of the second lens group S2 decreases, the refractive power weakens, which is not conducive to the correction of spherical aberration; if f / f s2 If the value exceeds its upper limit, the absolute value of the positive optical power of the second lens group S2 will increase, the refractive power will be enhanced, and the aberrations will increase, especially spherical aberration and coma. This will make the tolerance sensitivity of the lens group worse and will be detrimental to the assembly stability.

[0078] In one embodiment of this application, the length of the third lens group S3 along the optical axis and the combined focal length of the third lens group S3 satisfy the following:

[0079] 0.41≤TL3 / f s3 ≤0.45

[0080] Where TL3 represents the length of the third lens group S3 along the optical axis, f s3 This represents the combined focal length of the third lens group S3.

[0081] TL3 / f s3 Meeting the above conditional expression effectively suppresses the lens length, ensuring a compact lens size. If the conditional expression exceeds its upper limit, the length of the third lens group S3 relative to its focal length will increase, making lens size reduction more difficult. If the conditional expression is below its lower limit, the optical power of the third lens group S3 relative to its length will decrease, weakening its light refraction capability. This is detrimental to balancing the residual aberrations generated by the lens groups before the third lens group S3, resulting in poor resolution. Therefore, the lens of this embodiment not only ensures image quality but also effectively reduces lens size, thereby meeting the development needs of mirrorless cameras and other photographic equipment.

[0082] In one embodiment of this application, when the lens is focused at infinity, the total optical length of the lens and the effective focal length of the lens satisfy the following:

[0083] TTL / f≤1.88

[0084] Where TTL represents the total optical length, and f represents the effective focal length of the lens. A TTL / f ratio that satisfies the above condition ensures that the lens meets the requirements for a compact size, better meeting the portability needs of mirrorless cameras and other photographic equipment.

[0085] In one embodiment of this application, when the lens is focused at infinity, the lens's back focal length, half field of view, and effective focal length values ​​satisfy the following:

[0086] 0.89≤BFL / (f*tan w)≤0.96

[0087] Where BFL represents the back focal length of the lens, w represents the half field of view of the lens, and f represents the effective focal length of the lens.

[0088] 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 (BFL / (f*tan w)) is half the field of view, and is half the angle formed by the two edges of the lens at the maximum range through which the image of the target object can pass. BFL / (f*tan w) satisfying the above condition ensures the incident angle of the principal ray at the image plane in the off-axis field of view. If this condition is lower than its lower limit, the back focal length decreases, the incident angle of the principal ray in the off-axis field of view increases, and the relative illumination will decrease; if this condition is higher than its upper limit, the back focal length increases, and the overall length of the lens also increases, which is not conducive to achieving a compact lens size. BFL / (f*tan w) satisfying the above condition ensures the incident angle of the principal ray in the image plane in the off-axis field of view. If the 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 the condition is above its upper limit, the back focal length increases, and the overall length of the lens will also increase, which is not conducive to achieving a compact lens size.

[0089] This application also provides a photographic apparatus that employs the aforementioned lens. Specifically, the photographic apparatus can be a mirrorless camera, an SLR camera, a mobile phone with photographic capabilities, or other electronic devices. The photographic apparatus of this embodiment not only meets focusing requirements, but the lens also reduces field curvature through its focusing structure and effectively reduces various aberrations such as spherical aberration, coma, distortion, and chromatic aberration by forming a double Gaussian architecture on both sides of the stop aperture through at least some lenses. This comprehensively reduces lens aberrations and effectively improves photographic quality.

[0090] The present application will be further described below with reference to three embodiments.

[0091] The following are the data for the above conditional expressions corresponding to the three embodiments below:

[0092] Example 1 Example 2 Example 3 <![CDATA[f / f G1 ]]> -1.192 -0.811 -0.851 <![CDATA[f / f s2 ]]> 0.441 0.428 0.323 <![CDATA[TL3 / f s3 ]]> 0.419 0.416 0.431 TTL / f 1.865 1.819 1.821 BFL / (f*tanw) 0.920 0.944 0.916

[0093] Example 1:

[0094] like Figure 1 The optical path 2D structure diagram of the lens in Embodiment 1 is shown below, and its lens surface data is as follows:

[0095] Face number Surface type R value thickness Refractive index Abbe number Page 1 spherical -57.05 1.20 1.73 28.32 Page 2 spherical 35.92 6.80 2.00 25.43 Page 3 spherical -143.02 D3 Page 4 spherical 26.22 5.99 1.88 40.85 Page 5 spherical -49.87 3.00 1.75 25.05 Page 6 spherical 26.51 3.99 Stop spherical flat 3.04 8 aspherical -65.73 1.80 1.85 40.10 9 aspherical -252.96 1.95 10 spherical -39.74 1.35 1.58 40.75 Page 11 spherical 46.84 5.77 1.76 52.32 12 spherical -21.26 0.15 Page 13 spherical 68.74 6.99 1.90 37.37 Page 14 spherical -22.76 1.20 1.65 33.84 15 spherical 27.08 D15 Page 16 spherical flat 0.85 1.52 64.20 Page 17 spherical flat 0.50 Image spherical flat -

[0096] The variable spacing parameters for different object distances are as follows:

[0097] Object distance Infinity Recent (0.50M) D3(mm) 3.35 0.81 D15 (mm) 18.47 21.01

[0098] In this embodiment, the aspherical surface shape of the aspherical lens satisfies the following conditions:

[0099]

[0100] Where c is the curvature corresponding to the radius of curvature R, y is the radial coordinate (with the same unit as the lens length), and k is the conic coefficient. When k is less than -1, the surface curve is a hyperbola; when k is equal to -1, it is a parabola; when k is between -1 and 0, it is an ellipse; when k is equal to 0, it is a circle; and when k is greater than 0, it is an oval. A 4、 A 6、 A 8、 A 10、 A 12、 A 14、 A 16 This refers to the aspheric coefficients of higher order terms. The definition of aspheric surface shape will not be repeated below.

[0101] The table below shows the conic coefficient and higher-order aspheric coefficients of the aspherical lens in Example 1.

[0102] The aspherical data are as follows:

[0103] Face number k A4 A6 A8 A10 8 0 -7.66e-05 -3.82E-07 1.02E-08 -7.87E-11 9 0 -2.31E-05 -3.51E-07 1.18E-08 -9.63E-11

[0104] Face number A12 A14 A16 8 2.12E-13 0 0 9 3.00E-13 0 0

[0105] The optical parameters of the lens in Example 1 are as follows:

[0106] f Focal length (mm) when focusing at infinity 35.60 Fno aperture 1.46 w Half field of view (°) when focusing at infinity 31.18 H Half-image height (mm) 21.60 TTL Total optical length (mm) when focusing at infinity 66.40 BFL Back focal length (mm) when focusing at infinity 19.82 <![CDATA[f S1 ]]> Focal length (mm) of the first lens group S1 472.12 <![CDATA[f S2 ]]> Second lens group S2 focal length (mm) 80.70 <![CDATA[f s3 ]]> Focal length (mm) of the third lens group S3 45.89

[0107] Figures 2-4 The figures show the axial aberration curves, field curvature curves, and distortion curves at infinity for Example 1. The axial aberration curves represent the axial aberration of the lens as the aperture changes. The three curves correspond to the axial aberrations at wavelengths of 0.486 μm, 0.587 μm, and 0.656 μm, respectively. The horizontal axis represents the axial aberration value, and the vertical axis represents the normalized aperture. The field curvature curves represent 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 curves represent 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.

[0108] The above descriptions of the axial aberration curves, field curvature curves, and distortion curves are the same as those in other embodiments, and will not be repeated below.

[0109] From the figure Figures 2-4 The distortion is less than 0.45%, and there is no obvious image distortion; the axial chromatic aberration at the 0.7 aperture is no greater than 0.06mm, indicating excellent chromatic aberration suppression. Overall, the image quality is excellent.

[0110] Figures 5-7The figures shown are the axial aberration curve, field curvature curve, and distortion curve at the closest focusing point in Example 1. Compared to infinity, the axial chromatic aberration, field curvature, and distortion are all degraded at the closest focusing point, but the overall image quality is not excessively attenuated and can meet the general requirements of close-up photography.

[0111] Example 2:

[0112] like Figure 8 The following is a 2D structural diagram of the optical path of the lens in Embodiment 2, and the lens surface data are as follows:

[0113] Face number Surface type R value thickness Refractive index Abbe number Page 1 spherical -61.32 1.20 1.77 29.74 Page 2 spherical 71.40 0.15 Page 3 spherical 55.11 5.06 2.00 25.43 Page 4 spherical -171.51 D4 Page 5 spherical 26.27 6.29 1.88 40.85 Page 6 spherical -48.16 2.52 1.75 25.05 Page 7 spherical 26.24 4.51 Stop spherical flat 2.79 9 aspherical -74.89 2.00 1.85 40.10 10 aspherical -254.40 1.33 Page 11 spherical -30.60 1.49 1.58 40.75 12 spherical 34.64 6.30 1.79 47.49 Page 13 spherical -20.86 0.15 Page 14 spherical 58.18 5.32 1.88 40.85 15 spherical -33.52 2.18 1.65 33.84 Page 16 spherical 26.53 D16 Page 17 spherical flat 0.85 1.52 64.20 18 spherical flat 0.50 Image spherical flat -

[0114] Variable spacing parameters for different object distances:

[0115] Infinity Recent (0.50M) D4 (mm) 3.14 0.61 D16 (mm) 18.98 21.51

[0116] The table below shows the conic coefficient and higher-order aspheric coefficients of the aspherical lens in Example 2.

[0117] The aspherical data are as follows:

[0118] Face number k A4 A6 A8 A10 9 0 -8.75E-05 -4.70E-07 9.62E-09 -6.61E-11 10 0 -3.42E-05 -3.70E-07 1.07E-08 -7.94E-11

[0119] Face number A12 A14 A16 9 1.72E-13 0 0 10 2.25E-13 0 0

[0120] The optical parameters of the lens in Example 2 are as follows:

[0121] f Focal length (mm) when focusing at infinity 35.60 Fno aperture 1.45 w Half field of view (°) when focusing at infinity 31.18 H Half-image height (mm) 21.60 TTL Total optical length (mm) when focusing at infinity 64.76 BFL Back focal length (mm) when focusing at infinity 20.33 <![CDATA[f S1 ]]> Focal length (mm) of the first lens group S1 560.39 <![CDATA[f S2 ]]> Second lens group S2 focal length (mm) 83.25 <![CDATA[f s3 ]]> Focal length (mm) of the third lens group S3 45.07

[0122] Figures 8-11 The figures show the axial aberration curve, field curvature curve, and distortion curve at infinity for Example 2. The figures show that the distortion is less than 0.45%, with no significant image distortion; the axial chromatic aberration at a 0.7mm aperture is no greater than 0.07mm, indicating that the subject is not prone to chromatic aberration. Overall, the image quality is excellent.

[0123] Figures 12-14 The figures shown are the axial aberration curves, field curvature curves, and distortion curves at the closest focusing point in Example 2. Compared to infinity, the axial chromatic aberration, field curvature, and distortion are all degraded at the closest focusing point, but the overall image quality is not excessively attenuated and can meet the general requirements of close-up photography.

[0124] Example 3:

[0125] like Figure 15 The following is a 2D structural diagram of the optical path of the lens in Embodiment 3, and the lens surface data are as follows:

[0126] The variable spacing parameters for different object distances are as follows:

[0127] Object distance Infinity Recent (0.50M) D4 (mm) 3.69 1.16 D17 (mm) 18.38 20.96

[0128] The table below shows the conic coefficient and higher-order aspheric coefficients of the aspherical lens in Example 3. The aspherical data are as follows:

[0129]

[0130]

[0131] The optical parameters of the lens in Example 3 are as follows:

[0132] f Focal length (mm) when focusing at infinity 35.60 Fno aperture 1.45 w Half field of view (°) when focusing at infinity 31.17 H Half-image height (mm) 21.60 TTL Total optical length (mm) when focusing at infinity 64.82 BFL Back focal length (mm) when focusing at infinity 19.73 <![CDATA[f S1 ]]> Focal length (mm) of the first lens group S1 217.61 <![CDATA[f S2 ]]> Second lens group S2 focal length (mm) 110.28 <![CDATA[f s3 ]]> Focal length (mm) of the third lens group S3 44.93

[0133] Figures 16-18 The figures show the axial aberration curve, field curvature curve, and distortion curve at infinity for Example 3. The figures show that the distortion is less than 2.1%, with no significant image distortion; the axial chromatic aberration at a 0.7mm aperture is no greater than 0.07mm, indicating that the subject is not prone to chromatic aberration. Overall, the image quality is excellent.

[0134] Figures 19-21 The figures shown are the axial aberration curve, field curvature curve, and distortion curve at the closest focusing point in Example 3. Compared to infinity, the axial chromatic aberration, field curvature, and distortion at the closest focusing point are slightly increased, but the overall image quality is not excessively attenuated, which can meet the general needs of close-up photography.

[0135] 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 comprising: The lens comprises, from the object side to the image side, a first lens group with positive refractive power, a second lens group with positive refractive power, a diaphragm, and a third lens group with positive refractive power, the second lens group, the diaphragm, and the third lens group can move the same displacement amount along the optical axis direction relative to the first lens group to realize focusing at different object distances. At least part of the lens between the object side and the diaphragm and at least part of the lens between the diaphragm and the image side form a double Gauss structure.

2. The lens of claim 1, wherein From the object side to the image side, the lens comprises, in sequence, a negative refractive power lens, a positive refractive power lens, a positive refractive power lens, and a negative refractive power lens between the object side and the diaphragm, and comprises, in sequence, a negative refractive power lens, a negative refractive power lens, a positive refractive power lens, a positive refractive power lens, and a negative refractive power lens between the diaphragm and the image side.

3. The lens of claim 2, wherein The first lens group comprises, from the object side to the image side, a first lens with negative refractive power and a second lens with positive refractive power, the first lens is a double concave structure, and the second lens is a double convex structure. The second lens group comprises, from the object side to the image side, a third lens with positive refractive power and a fourth lens with negative refractive power, the third lens is a double convex structure, and the fourth lens is a double concave structure. The third lens group comprises a fifth lens with negative refractive power, a sixth lens with negative refractive power, a seventh lens with positive refractive power, an eighth lens with positive refractive power, and a ninth lens with negative refractive power, the fifth lens is a meniscus structure, the sixth lens is a double concave structure, the seventh lens is a double convex structure, the eighth lens is a double convex structure, and the ninth lens is a double concave structure.

4. The lens of claim 3, wherein The third lens and the fourth lens are combined into a cemented lens group, and the third lens group comprises at least one group of positive refractive power lenses and negative refractive power lenses combined into a cemented lens group.

5. The lens of claim 3, wherein The fifth lens is a molded glass aspheric lens.

6. The lens of claim 3, 4 or 5, wherein When the lens is focused at infinity, the focal length of the first lens and the effective focal length of the lens satisfy: -1.35 < f / f G1 ≤ -0.78 wherein f denotes the effective focal length of the lens, f G1 denotes the focal length of the first lens.

7. The lens of claim 3, 4 or 5, wherein The refractive index of the second lens satisfies: nd≥2.00 wherein nd represents the refractive index of the second lens.

8. The lens of any one of claims 1-5, wherein, When the lens is focused at infinity, the combined focal length of the second lens group and the effective focal length of the lens satisfy: 0.29 < f / f s2 < 0.46 wherein f denotes an effective focal length of the lens, f s2 denotes a composite focal length of the second lens group.

9. The lens of any one of claims 1-5, wherein, The length of the third lens group in the optical axis direction and the combined focal length of the third lens group satisfy: 0.41 < TL3 / f s3 ≤ 0.45 wherein TL3 represents a length of the third lens group in the optical axis direction, f s3 represents a composite focal length of the third lens group.

10. The lens of any one of claims 1-5, wherein, When the lens is focused at infinity, the total optical length of the lens and the effective focal length of the lens satisfy: TTL / f≤1.88 wherein TTL represents the total optical length, and f represents the effective focal length of the lens.

11. The lens of any one of claims 1-5, wherein, When the lens is focused at infinity, the back focal length of the lens, the half field of view, and the effective focal length satisfy: 0.89≤BFL / (f*tan w)≤0.96 wherein BFL represents the back focal length of the lens, w represents the half field of view of the lens, and f represents the effective focal length of the lens.

12. A photographic apparatus characterized by comprising: The photographic equipment adopts the lens according to any one of claims 1-12.

Images