Large-aperture fisheye imaging full-frame lens

Abstract

The utility model discloses a large-aperture fisheye imaging full-frame lens. The large-aperture fisheye imaging full-frame lens comprises a first lens group, an iris diaphragm and a second lens group which are sequentially arranged from an object side to an image side, the first lens group has positive focal power and is fixed in position; the first lens group comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens; the second lens group has positive focal power and is variable in position; the second lens group comprises a seventh lens, an eighth lens, a ninth lens, a tenth lens and an eleventh lens; wherein the first lens, the second lens and the third lens are meniscus lenses with convex surfaces facing the object side, and one of the first lens, the second lens and the third lens is an aspheric lens. According to the utility model, the first three lenses in the first lens group are the meniscus lenses with the convex surfaces facing the object side, and one lens is the aspheric lens, so that a 220-degree super-large view field angle is realized, the modulation transfer function (MTF) is effectively optimized and improved, and the aperture of the lenses is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of lens especially relates to a large aperture fisheye imaging full frame lens. BACKGROUND

[0002] With the rapid development of science and technology, optical imaging plays a crucial role in many fields such as photography, security monitoring, virtual reality, etc. People's demand for image quality is increasing, and they expect lenses to capture high-resolution, wide-field, color-accurate and light-adaptive images in various complex scenarios. Especially in some professional photography, panoramic monitoring and immersive virtual reality scenarios, the performance requirements for lenses are more stringent.

[0003] Traditional ordinary lenses mostly only provide a relatively narrow field of view, mostly only 180° field of view, which is difficult to meet the application scenarios that require wide-angle imaging. For example, in the field of panoramic photography, conventional lenses cannot capture enough wide space in one shot, and photographers often need to take multiple shots and splice images, which is not only cumbersome, but also prone to image mismatching, color differences and other problems at the splicing point, which seriously affects the quality and continuity of panoramic images. Even some lenses that claim to have wide-angle functions, their field of view is usually far from the ultra-wide field of view required by professional applications, and cannot give users an immersive panoramic visual experience.

[0004] There are also fisheye full-frame lenses on the market, which often sacrifice resolution when pursuing large aperture to adapt to different lighting conditions and allow more light into the lens to facilitate clear image capture in dark environments. This is because the large aperture design may introduce spherical aberration, coma and other aberrations, making the details at the edge of the image unclear.

[0005] Therefore, it is necessary to design a fisheye full-frame lens that can improve MTF in a large field of view and reduce the lens aperture. UTILITY MODEL CONTENT

[0006] The utility model aims at overcoming the defects of prior art, and provides a large aperture fisheye imaging full frame lens.

[0007] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme:

[0008] The utility model provides a large aperture fisheye imaging full frame lens, which comprises a first lens group, a variable diaphragm and a second lens group arranged in order from the object side to the image side.

[0009] The first lens group has positive refractive power and is fixed in position, and the first lens group comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens.

[0010] The second lens group has positive focal length and is movable, and comprises a seventh lens, an eighth lens, a ninth lens, a tenth lens and an eleventh lens.

[0011] The first lens group comprises a first lens, a second lens and a third lens.

[0012] Further, the second lens group is provided with two sets of double cemented lenses.

[0013] Further, the first lens group is provided with one set of double cemented lenses.

[0014] Further, the lenses in the second lens group are made of fluorite material.

[0015] Further, the first lens group and the second lens group satisfy the following relationship: 1.85

[0016] Further, the refractive index of at least four lenses in the first lens group is greater than 1.8 and less than 1.9, and the refractive index of at least one lens in the first lens group is greater than 1.9 and less than 2.

[0017] Further, the Abbe number of at least two lenses in the second lens group is greater than 80 and less than 90.

[0018] Further, the total optical length of the lens is less than 107 mm and greater than 103 mm.

[0019] Further, the third lens is the aspheric lens.

[0020] The beneficial effect of the utility model compared with prior art is: a large aperture fisheye imaging full frame lens, including first lens group, variable diaphragm and second lens group arranged in order from object side to image side;The first lens group has positive refractive power and is fixed in position, and the first lens group includes first lens, second lens, third lens, fourth lens, fifth lens and sixth lens;The second lens group has positive refractive power and is variable in position, and the second lens group includes seventh lens, eighth lens, ninth lens, tenth lens and eleventh lens;Among them, the first lens, the second lens and the third lens are convex moon-shaped lenses all facing the object side, and one of the first lens, the second lens and the third lens is an aspherical lens.The utility model takes the convex moon-shaped lens all facing the object side in the first three lenses of the first lens group, and one of the lenses is an aspherical lens, realizes 220° super large field angle, effectively optimizes and improves the modulation transfer function (MTF) and reduces the lens aperture.

[0021] The above description is only a summary of the technical scheme of the utility model, in order to more clearly understand the technical means of the utility model, can be implemented according to the content of the specification, and in order to let the above and other purpose characteristics and advantages of the utility model can be more obvious and easy to understand, the following preferred embodiments are described in detail as follows. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical scheme of the utility model embodiment, the following will briefly introduce the drawings needed in the embodiment description, obviously, the drawings in the following description are some embodiments of the utility model, and for those skilled in the art, other drawings can also be obtained without creative labor according to these drawings.

[0023] Figure 1 The structure schematic diagram of a large aperture fisheye imaging full frame lens provided by the embodiment of the utility model is shown in the figure;

[0024] Figure 2 The exploded view of the first lens group in a large aperture fisheye imaging full frame lens provided by the embodiment of the utility model is shown in the figure;

[0025] Figure 3 The exploded view of the second lens group in a large aperture fisheye imaging full frame lens provided by the embodiment of the utility model is shown in the figure;

[0026] Figure 4 The longitudinal chromatic aberration schematic diagram provided by the embodiment of the utility model is shown in the figure;

[0027] Figure 5 The relative luminance schematic diagram provided by the embodiment of the utility model is shown in the figure;

[0028] Figure 6The diffused spot diagram provided by the embodiment of the present utility model;

[0029] Figure 7 The MTF diagram provided by the embodiment of the present utility model;

[0030] Figure 8 The MTF defocus curve diagram provided by the embodiment of the present utility model.

[0031] Reference signs

[0032] 1, first lens group;11, first lens;12, second lens;13, third lens;14, fourth lens;15, fifth lens;16, sixth lens;2, second lens group;21, seventh lens;22, eighth lens;23, ninth lens;24, tenth lens;25, eleventh lens. Specific implementation

[0033] The technical scheme of the present utility model will be described clearly and completely in combination with the embodiment of the present utility model, obviously, the described embodiment is a part of the embodiment of the present utility model, rather than all the embodiment. Based on the embodiment in the present utility model, all other embodiments obtained by the person skilled in the art without making creative labor belong to the protection scope of the present utility model.

[0034] In the description of the present utility model, it is understood that the orientation or position relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present utility model and simplifying the description, and cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the present utility model.

[0035] In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "multiple" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0036] In the utility model, unless another definite provision and limitation, the terms "mount", "link", "connect", "fix" and so on should do the broad sense understanding, for example, can be fixed connection, also can be detachable connection, or be integrated;Can be mechanical connection, also can be electrical connection;Can be directly connected, also can be indirectly connected through the intermediate medium, can be the communication of two elements or the interaction of two elements, unless another definite limitation.For the ordinary skilled person in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0037] In the utility model, unless another definite provision and limitation, the first feature is "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium.Moreover, the first feature "over", "above" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature.The first feature "under", "below" and "on" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0038] It should be noted that when an element is referred to as "fixed to" or "provided on" another element, it can be directly on the other element or there can be a middle element.When an element is referred to as "connected to" another element, it can be directly connected to the other element or there can be a middle element.The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and are not the only implementation.

[0039] As shown in Figures 1 to 3 The utility model discloses a big aperture fisheye imaging full frame lens, including first lens group 1, variable diaphragm (not shown in drawing) and second lens group 2 from object side to image side are arranged in proper order, first lens group 1 has positive refractive power and position is fixed, and first lens group 1 includes first mirror 11, second mirror 12, third mirror 13, fourth mirror 14, fifth mirror 15 and sixth mirror 16, and second lens group 2 has positive refractive power and position is variable, and second lens group 2 includes seventh mirror 21, eighth mirror 22, ninth mirror 23, tenth mirror 24 and eleventh mirror 25, wherein first mirror 11, second mirror 12 and third mirror 13 are convex surface and all are crescent-shaped mirror towards object side, and one of first mirror 11, second mirror 12 and third mirror 13 is aspherical mirror.

[0040] Optical power is a physical quantity used to measure the ability of a lens to converge or diverge light rays. A positive optical power indicates that the lens group has the ability to converge light rays, therefore, the first lens group 1 has a positive optical power, and its main function is to preliminarily converge and adjust the light rays entering the lens, laying the foundation for the subsequent imaging process. For example, in actual shooting, when the light rays enter the lens from the object side, the first lens group 1 can guide the divergent light rays towards the optical axis direction, so that the light rays are more concentrated into the subsequent optical elements.

[0041] The six lenses (six lenses refer to the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, and the sixth lens 16) of the first lens group 1 are fixed in position during the focusing process. This design can provide a relatively stable initial convergence condition for the light rays entering the lens. In contrast to the mobility of the second lens group 2, the fixed position of the first lens group 1 as part of the lens optical system helps the stability of the overall structure, and provides a basic light convergence function in the imaging process without the need to adjust the focal length by changing the position.

[0042] The second lens group 2 has a positive optical power, and like the first lens group 1, because the first lens group 1 has preliminarily converged the light rays, the second lens group 2 further converges the light rays on this basis to meet the requirements of imaging under different shooting distances and other situations.

[0043] The five lenses (five lenses refer to the seventh lens 21, the eighth lens 22, the ninth lens 23, the tenth lens 24, and the eleventh lens 25) of the second lens group 2 are variable in position during the focusing process, that is, when the focal length needs to be adjusted (such as shooting objects at different distances), the second lens group 2 can change the focal length of the entire lens system by moving its position, and this movement can change the propagation path of the light rays in the lens, so that the lens can adapt to the imaging of objects at different object distances, thereby realizing the focusing function. This design makes the lens have a certain flexibility, which can meet the needs of various shooting scenes.

[0044] The variable aperture is an optical element that can adjust the size of its aperture. In the lens system, the variable aperture is located between the first lens group 1 and the second lens group 2, and is mainly used to control the light flux passing through the lens. Specifically, when the aperture of the variable aperture becomes larger, more light rays can pass through the lens, which will increase the brightness of the image. For example, in a low-light shooting environment, the aperture of the variable aperture can be increased to allow more light rays to reach the imaging surface, thereby making the captured image brighter. Conversely, when the aperture of the variable aperture becomes smaller, the light rays passing through the lens decrease, and the brightness of the image decreases. This adjustable feature allows the lens to adapt to different lighting conditions for shooting.

[0045] By adjusting the aperture size of the variable aperture, the light flux entering the subsequent optical elements inside the lens (such as the second lens group 2) can be precisely controlled, thereby obtaining images with appropriate brightness under different lighting conditions. For example, in a strong light environment, reducing the aperture of the aperture can prevent too much light from entering the lens, avoiding overexposure of the image; in a weak light environment, increasing the aperture of the aperture can allow sufficient light to enter, ensuring that the image has sufficient brightness.

[0046] The first lens group 1 includes six lenses, of which the first three lenses (i.e., the first lens 11, the second lens 12, and the third lens 13) are convex crescent-shaped lenses with convex surfaces facing the object side. This design helps control the incident angle and propagation path of light. For example, in the initial stage of light entering the lens, the convex crescent-shaped lens with the convex surface facing the object side can make the light enter the lens system more smoothly, reducing reflection and scattering loss of light.

[0047] In this embodiment, the third lens 13 is an aspherical lens. In the case of a large field of view, the aspherical design of the third lens 13 can effectively correct aberrations, especially spherical aberration and coma. Compared with traditional spherical lenses, aspherical lenses can more accurately control the refraction of light, making the focusing of light on the image plane more accurate, thereby improving the clarity and resolution of the image.

[0048] It should be noted that in optical lens design, crescent-shaped lenses describe the shape of the lens, i.e., the two curved surfaces of the lens exhibit a crescent-like shape, and here it is specified that the convex surface faces the object side. Aspherical lenses describe the surface shape of the lens, i.e., the surface of the lens is not a traditional spherical surface, but an aspherical design. Therefore, the third lens can be both crescent-shaped (shape) and aspherical (surface shape) without any contradiction.

[0049] The utility model discloses a first lens group 1 in the first three lenses adopts the crescent-shaped lens with the convex surface all facing the object side, and one of the lenses is an aspherical lens, realizes 220 ° super large field of view angle, effectively optimizes and improves modulation transfer function (MTF) and reduces lens aperture at the same time.

[0050] In one embodiment, the first lens group 1 is provided with a set of double cemented lenses, and the second lens group 2 is provided with two sets of double cemented lenses,

[0051] The double cemented lens refers to two lenses with different optical properties that are tightly cemented together. In the first lens group 1, there is a set of double cemented lenses, for example, one of the two lenses in the double cemented lens is made of glass material with a higher refractive index, which is used to effectively converge light rays, and the other lens is made of material with appropriate Abbe number, which mainly functions to compensate for chromatic aberration. In the actual light propagation process, when the light rays enter the first lens group 1 from the object side, this set of double cemented lenses can accurately control the light rays. It not only adjusts the propagation direction of the light rays to meet the requirements of subsequent imaging, but also significantly reduces the chromatic aberration caused by the difference in refraction of different color light rays.

[0052] The second lens group 2 is provided with two sets of double cemented lenses, which further enhances the control and aberration correction ability of the lens for light rays. One of the double cemented lenses can focus on further convergence and chromatic aberration correction of the light rays, and the other can optimize the field curvature and other aberrations. For example, when shooting a distant object, the light rays enter the second lens group 2 after being preliminarily processed by the first lens group 1. The first set of double cemented lenses ensures that the light rays can be accurately focused on the image plane through precise refraction, while reducing chromatic dispersion. The second set of double cemented lenses corrects the possible field curvature phenomenon, making the imaging surface more flat and the image clarity more uniform across the entire image.

[0053] In an embodiment, the lenses in the second lens group 2 are made of fluorite material, which has the advantages of low dispersion and high transparency, and can further reduce chromatic dispersion and improve the optical performance of the lens.

[0054] In an embodiment, the first lens group 1 and the second lens group 2 satisfy the following relationship: 1.85 < f2 / f1 < -2.15, where f1 represents the focal length of the first lens group 1, and f2 represents the focal length of the second lens group 2.

[0055] In the actual lens system, when the light rays enter the lens from the object side, they first pass through the first lens group 1. The first lens group 1 has a positive focal power, and its focal length f1 plays a role in preliminary convergence of the light rays, adjusting the direction and angle of the light rays. For example, when shooting a distant landscape scene, the light rays enter at a wide angle, and the first lens group 1 directs the light rays towards the optical axis according to its focal length characteristics, making them more concentrated in the subsequent optical path.

[0056] The light rays then reach the second lens group 2, which also has positive focal power. The focal length f2 of the second lens group 2 and the focal length f1 of the first lens group 1 maintain a specific proportional relationship. This proportional relationship ensures that the two lens groups can work together to achieve good imaging results under different shooting distances and scenes. For example, when shooting close-range objects, the focal length change of the second lens group 2 can accurately compensate for the light convergence of the first lens group 1 according to this relationship, so that the object can be clearly imaged on the image plane, avoiding image blur or distortion caused by mismatched focal lengths.

[0057] The specific proportional relationship constraint helps to achieve a large field of view while ensuring the imaging quality of the entire lens system. When shooting panoramic photos, the focal length matching of the first lens group 1 and the second lens group 2 can make the objects at the edge of the frame also clearly imaged, while maintaining low aberrations.

[0058] In an embodiment, the refractive index of at least four lenses in the first lens group 1 is greater than 1.8 and less than 1.9, and the refractive index of at least one lens in the first lens group 1 is greater than 1.9 and less than 2.

[0059] In actual lens design, the refractive index of at least four lenses is greater than 1.8 and less than 1.9, which plays an important role in the propagation of light. For example, when light enters the first lens group 1 from the object side, these lenses with moderate refractive index can bend and converge the light appropriately, making the light propagation path within the lens group more reasonable. They can effectively control the degree of light divergence and guide the light towards the optical axis direction, laying a good foundation for subsequent imaging process. When shooting an indoor scene with complex light, these lenses can orderly adjust the light from different directions to avoid excessive scattering of light, thereby improving the clarity and contrast of the image.

[0060] At the same time, the refractive index of at least one lens in the first lens group 1 is greater than 1.9 and less than 2, which can further enhance the focusing effect of the light after the initial processing of the light by the front lenses. For example, when shooting distant objects, this high-refractive-index lens can compensate for the energy loss and divergence of light during long-distance propagation, so that the light can be more concentrated on the image plane, thereby improving the resolution of the image and making the details of distant objects clearer. When shooting landscape photos, the distant mountains, trees and other scenery can present more detailed and rich details in the image, enhancing the sense of layering and stereoscopic of the picture.

[0061] In an embodiment, the Abbe number of at least two lenses in the second lens group 2 is greater than 80 and less than 90.

[0062] Abbe number is an important indicator to measure the degree of dispersion of the lens, and higher Abbe number means lower dispersion. When the light passes through the second lens group 2, the lenses with Abbe numbers in a certain range can effectively reduce the separation phenomenon of different color lights. For example, when shooting natural scenery with bright colors, such as a field of flowers in the sunset, the light contains rich color components. When the light passes through the lenses of the second lens group 2, these high Abbe number lenses can ensure that different colors of light such as red, green, and blue are almost focused on the image plane at the same time, avoiding color edge blur or color stripe dispersion problems, so that the color of the image is more true, bright and clear, greatly improving the color restoration degree of imaging.

[0063] At the same time, when working with the first lens group 1, the lenses of the second lens group 2 can further correct the residual chromatic aberration that may exist after passing through the first lens group 1. Since the first lens group 1 may introduce a certain degree of chromatic aberration in the light processing process, the lenses with appropriate Abbe number in the second lens group 2 can adjust the refractive path of different color lights in a targeted manner, so that the final imaging reaches a higher standard in color accuracy. In actual product shooting applications, for some color-critical goods such as jewelry and art, using this lens can accurately present the true color of the object, providing reliable image basis for product display and identification.

[0064] In an embodiment, the total optical length of the lens is less than 107 mm and greater than 103 mm.

[0065] The total optical length of the lens refers to the distance from the front end of the lens (the surface of the lens that the light first contacts) to the rear end of the lens (the surface of the last lens before the imaging position). This length covers the distribution range of all optical elements (such as lenses, diaphragms, etc.) in the light axis direction, which is an important indicator to measure the size of the lens.

[0066] The total optical length of the lens is designed to be less than 107 mm and greater than 103 mm, which is set by considering the performance and actual application requirements of the lens. On the one hand, a shorter total optical length is beneficial to the miniaturization of the lens, making it more convenient to use in some space-limited devices (such as small cameras, portable imaging devices, etc.). On the other hand, the lower limit of the total optical length is set to ensure that there is enough space inside the lens to reasonably layout various optical elements to achieve the desired optical performance, such as large field of view, high resolution, large aperture, and small dispersion.

[0067] This size range is closely related to the optical performance of a lens. For example, to achieve a 220° ultra-wide field of view and a large aperture, the lenses inside the lens need to have appropriate sizes and arrangements. The limitation of the total optical length ensures that these lenses are arranged within a reasonable space, avoiding situations where the space is too small to achieve the designed optical performance, or too large to make the lens size unsuitable for the miniaturization requirements of practical applications. At the same time, a suitable total optical length range also helps control aberrations, because the distance between lenses is a factor affecting aberrations. Within this specified range, the relative positions between lenses can be better optimized, thereby reducing aberrations and improving image quality.

[0068] To better understand the technical advantages of the lens in this application, such as Figures 4 to 8 As shown, where Figure 4 This diagram illustrates the longitudinal chromatic aberration, showcasing the lens's performance in this embodiment. The diagram provides a visual understanding of the lens's varying degrees of focus on different colors of light, thus allowing assessment of the lens's chromatic aberration control performance. Figure 4 It can be concluded that the lens of this application has good longitudinal chromatic aberration control in the embodiments, indicating that the lens has good consistency in focusing on different colors of light, effectively reducing the image color deviation problem caused by chromatic aberration. Figure 5 This is a diagram illustrating relative illumination, used to show the relative illumination of the lens under different fields of view. From Figure 5 It can be seen that the lens of this application has relatively stable relative illumination performance under different fields of view, which means that the light is distributed more evenly in the image and can provide relatively consistent brightness in different areas, thus ensuring the stability of image quality. Figure 6 This diagram illustrates the speckle of confusion, showing the size and shape of the speckle formed on the image plane after light passes through the lens. The size and shape of the speckle are closely related to the lens's image sharpness; a smaller and more regular speckle means the lens can better focus light onto a single point. From Figure 6 It is known that the blur spot formed after the light passes through the lens of this application is small and relatively regular, which indicates that the lens can focus the light on the image plane well, which helps to achieve higher imaging resolution and clarity, and makes the image details clearer. Figure 7 This is a schematic diagram of MTF (Modulation Transfer Function). MTF is used to measure the imaging quality of a lens for targets at different spatial frequencies. Figure 7 This shows the MTF values ​​of the lens at different spatial frequencies. A higher MTF value indicates that the lens can better convey the detail and contrast of an object. From Figure 7 It is known that the lens of this application has a high MTF value at different spatial frequencies, indicating that the lens has a strong ability to transmit object details and contrast, performs well in terms of resolution, and can meet the requirements of high-resolution imaging. Figure 8The off-focus curve is a schematic diagram for showing the change of the MTF of the lens in the off-focus state, which is very important for analyzing the depth of field characteristics of the lens and the change of the imaging quality at different focus positions, and can help to understand the attenuation law of the imaging quality of the lens in the actual shooting when the focus point deviates from the ideal position. Figure 8 It can be known that by observing the trend of the curve, it can be judged that within which off-focus range the lens of the present application can still maintain a relatively high MTF value, so as to determine the effective depth of field range of the lens.

[0069] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical range disclosed by the present application, and these modifications or replacements should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A large aperture fisheye imaging full-frame lens, characterized in that, The lens comprises, arranged from the object side to the image side in order, a first lens group, a variable diaphragm and a second lens group; The first lens group has positive focal power and is fixed in position, and comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens; The second lens group has positive focal power and is variable in position, and comprises a seventh lens, an eighth lens, a ninth lens, a tenth lens and an eleventh lens; The first lens, the second lens and the third lens are convex meniscus lenses with their convex surfaces facing the object side, and one of the first lens, the second lens and the third lens is an aspherical lens.

2. The large aperture fisheye imaging full-frame lens according to claim 1, characterized in that, The second lens group is provided with two sets of doublet lenses.

3. The large-aperture fisheye imaging full-frame lens according to claim 1 or 2, characterized in that, The first lens group is provided with one set of doublet lenses.

4. The large aperture fisheye imaging full-frame lens according to claim 1, characterized in that, The lenses in the second lens group are made of fluorite.

5. The large aperture fisheye imaging full-frame lens according to claim 1, characterized in that, The first lens group and the second lens group satisfy the following relationship: 1.85 < f2 / f1 < -2.15, wherein f1 represents the focal length of the first lens group, and f2 represents the focal length of the second lens group.

6. The large aperture fisheye imaging full-frame lens according to claim 1, wherein, The refractive index of at least four lenses in the first lens group is greater than 1.8 and less than 1.9, and the refractive index of at least one lens in the first lens group is greater than 1.9 and less than 2.

7. The large aperture fisheye imaging full-frame lens according to claim 1, characterized in that, The Abbe number of at least two lenses in the second lens group is greater than 80 and less than 90.

8. The large aperture fisheye imaging full-frame lens according to claim 1, wherein, The total optical length of the lens is less than 107 mm and greater than 103 mm.

9. The large aperture fisheye imaging full-frame lens according to claim 1, wherein, The third lens is the aspherical lens.

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