Intrafocal full-frame lens and image pickup device

Abstract

The application is suitable for the field of photographic technology, and provides an inner focus full-frame lens and an image pickup device, which comprises, from an object side to an image side, a first lens group with positive refractive power, an aperture stop, a second lens group with positive refractive power, and a third lens group with negative refractive power; the second lens group comprises an aspherical lens located at the image side end of the second lens group; the third lens group comprises an aspherical lens located at the object side end of the third lens group; in the focusing process of the inner focus full-frame lens, the second lens group moves from the object side to the image side to realize focusing; the inner focus full-frame lens satisfies the following conditional expressions: 1.00 <= F1 / F <= 1.20, (1); 0.75 <= F2 / F <= 0.95, (2); -1.10 <= F3 / F <= -0.90, (3); 1.55 <= TTL / F <= 1.75, (4); by reasonably configuring the position of the aspherical lens and combining the focal length range and the moving mode of the lens group, the front aperture size of the lens is effectively controlled, and the overall weight of the lens is significantly reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of photography, and particularly relates to an inner focus full-frame lens and a camera device. BACKGROUND

[0002] With the maturity and popularity of the full-frame mirrorless camera market, the expectations of photography users for the matching lens system are no longer limited to excellent imaging quality. The trend of camera miniaturization and light weight is driving the market to demand higher portability, intelligence and cost performance of the lens. In the field of large aperture lenses, traditional F1.8 or F1.4 standard lenses are commonly used by users. The large aperture feature can provide advantages such as shallow depth of field, soft background, and improved light intake in low light environments, and is widely used in portrait photography, night photography and other scenes.

[0003] However, in order to pursue a larger aperture and ideal imaging quality, such traditional large aperture standard lenses often need to use complex optical structure design, resulting in obvious shortcomings of the traditional large aperture standard lens. On the one hand, in order to correct various aberrations such as spherical aberration, coma, dispersion and the like caused by large aperture, it is necessary to configure too many high refractive index lenses or precise aspherical lenses, resulting in an increase in the number of optical elements, and thus leading to high material and production costs. Ultimately, the price of high-performance large aperture lenses remains at a high level, making it difficult to meet the demands of the majority of entry-level and advanced users for cost performance. On the other hand, the light power distribution mode and structure layout of the traditional lens are not optimized, resulting in a generally long total track length (TTL) of the lens, often exceeding 90mm or even reaching more than 100mm. At the same time, the front lens aperture needs to be increased to match the large aperture design, which not only makes the lens bulky and heavy, but also makes the lens appear top-heavy when paired with a compact mirrorless camera body, seriously affecting portability. SUMMARY

[0004] The purpose of the present application is to provide an inner focus full-frame lens and a camera device, aiming to solve the problem of large front aperture and heavy lens weight of existing large aperture standard lenses.

[0005] In a first aspect, the present application provides an inner focus full-frame lens, which comprises, in order from the object side to the image side, a first lens group with positive refractive power, an aperture stop, a second lens group with positive refractive power, and a third lens group with negative refractive power. The second lens group comprises an aspherical lens located at the image side end of the second lens group. The third lens group comprises an aspherical lens located at the object side end of the third lens group. During the focusing process of the inner focus full-frame lens, the second lens group moves from the object side to the image side to achieve focusing.

[0006] The inner focus full-frame lens satisfies the following conditional expression:

[0007] 1.00≤F1 / F≤1.20, (1)

[0008] 0.75≤F2 / F≤0.95, (2)

[0009] -1.10≤F3 / F≤-0.90, (3)

[0010] 1.55≤TTL / F≤1.75, (4)

[0011] wherein F1 represents a focal length of the first lens group, F2 represents a focal length of the second lens group, F3 represents a focal length of the third lens group, TTL represents an optical total track length of the inner focus full-frame lens, and F represents a focal length of the inner focus full-frame lens.

[0012] In some embodiments, the first lens group comprises at least a doublet lens group, and the doublet lens group satisfies the following conditional expression:

[0013] 15.0≤|Vd3-Vd4|≤22.0, (5)

[0014] wherein Vd3 represents an Abbe number of a first lens in the doublet lens group, and Vd4 represents an Abbe number of a second lens in the doublet lens group.

[0015] In some embodiments, the first lens group comprises at least a lens with an Abbe number Vd≥75; and / or

[0016] the first lens group comprises at least a lens with a refractive index Nd≥1.9.

[0017] In some embodiments, the first lens group comprises, in order from the object side to the image side, a first lens with positive refractive power, a second lens with negative refractive power, a third lens with negative refractive power, and a fourth lens with positive refractive power.

[0018] In some embodiments, the first lens has a refractive index Nd≥1.9, the second lens has an Abbe number Vd≥75, and the third lens and the fourth lens are combined into a first cemented lens.

[0019] In some embodiments, the second lens group comprises, in order from the object side to the image side, a fifth lens with negative refractive power, a sixth lens with positive refractive power, and a seventh lens with positive refractive power.

[0020] In some embodiments, the fifth lens and the sixth lens are combined into a second cemented lens, and the seventh lens is an aspherical lens.

[0021] In some embodiments, the third lens group comprises, in order from the object side to the image side, an eighth lens having negative refractive power and a parallel flat plate.

[0022] In some embodiments, the eighth lens is an aspherical lens.

[0023] In a second aspect, the present application provides an image pickup device comprising an image sensor configured to receive an optical image formed by the internal focus full-frame lens, and the internal focus full-frame lens as described above.

[0024] The internal focus full-frame lens in the present application, through reasonable refractive power distribution and the introduction of aspherical lenses, ensures high optical performance and compact structure of the lens together. One aspherical lens is integrated at the image side end of the second lens group with positive refractive power, and the special surface of the aspherical lens is used to correct spherical aberration and coma. Another aspherical lens is arranged at the object side end of the third lens group with negative refractive power, which effectively optimizes the control of astigmatism, distortion and field curvature. Through the synergistic effect of the two aspherical lenses, the precise correction of multiple aberrations is realized under the premise of reducing the total number of lenses, and the imaging quality and cost control are considered. In addition, the third lens group close to the image plane bears negative refractive power, which cooperates with the second lens group with positive refractive power to form a rear group structure similar to a telephoto lens, greatly shortening the physical total length of the lens and reducing the volume and weight of the lens, thereby realizing the design of super miniaturization. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a sectional view of the internal focus full-frame lens provided by the first embodiment of the present application in the Y-Z plane;

[0026] Figure 2 is a schematic diagram of spherical aberration when the internal focus full-frame lens provided by the first embodiment of the present application is focused at infinity;

[0027] Figure 3 is a schematic diagram of field curvature and distortion when the internal focus full-frame lens provided by the first embodiment of the present application is focused at infinity. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0029] It should be understood that the term "includes" when used in this specification and the appended claims indicates the presence of the described features, integers, steps, operations, elements, and / or components but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used in this specification and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "first," "second," and similar terms do not imply any order, quantity, or importance, but are used to distinguish one element from another, and the terms "connected" and "coupled" and / or similar terms are used in an inclusive sense, and generally mean joined together or linked together, whether directly or indirectly. The terms "upper," "lower," "left," "right," and the like are used herein merely to denote different relative positions, and thus can be used interchangeably with "superior," "inferior," "lateral," "medial," and the like.

[0030] In order to keep the following description of the embodiments of the present application clear and concise, detailed description of some known functions and known components is omitted in the specification.

[0031] The present application provides an inner focusing full-frame lens, sequentially comprising a first lens group with positive refractive power, an aperture stop, a second lens group with positive refractive power, and a third lens group with negative refractive power from an object side to an image side, the second lens group comprising an aspherical lens located at an image side end of the second lens group, the third lens group comprising an aspherical lens located at an object side end of the third lens group, in a focusing process of the inner focusing full-frame lens, the second lens group moves from the object side to the image side to achieve focusing.

[0032] The inner focusing full-frame lens satisfies the following conditional expressions:

[0033] 1.00≤F1 / F≤1.20, (1) ;

[0034] 0.75≤F2 / F≤0.95, (2) ;

[0035] -1.10≤F3 / F≤-0.90, (3) ;

[0036] 1.55≤TTL / F≤1.75, (4) ;

[0037] wherein F1 represents the focal length of the first lens group, F2 represents the focal length of the second lens group, F3 represents the focal length of the third lens group, TTL represents the total optical length of the inner focusing full-frame lens, and F represents the focal length of the inner focusing full-frame lens.

[0038] The embodiment of the present application introduces an aspherical lens reasonably, compensates for the traditional spherical lens aberration by the special surface of the aspherical lens, and the aspherical lenses arranged in the second lens group and the third lens group undertake the regulation of the spherical aberration, coma and astigmatism respectively, so that the high-performance imaging quality is realized with the lowest lens number and cost, and different from the traditional double Gauss and its derivative structure which usually adopts positive refractive power in the rear group to converge light, the third lens group close to the image plane is innovatively set as negative refractive power and cooperates with the positive refractive power group in front to form a rear group configuration similar to a telephoto structure, which effectively compresses the total optical length and realizes the ultra-compact design of the lens structure on the one hand, and the introduction of negative refractive power can more efficiently correct the field curvature and distortion on the other hand.

[0039] The first lens group in the embodiment of the present application has positive refractive power, so that the light entering the lens can be preliminarily focused. In addition, the focal length of the first lens group and the focal length of the inner focus full-frame lens satisfy: 1.00≤F1 / F≤1.20, so that if the ratio of the focal length of the first lens group to the focal length of the inner focus wide-angle camera lens exceeds the lower limit, it indicates that the refractive power of the first lens group is too strong, although the aperture size of the subsequent lens group can be reduced, but significant spherical aberration and coma will be introduced, thereby bringing great challenges to aberration correction and affecting the imaging quality. If the ratio of the focal length of the first lens group to the focal length of the inner focus full-frame lens exceeds the upper limit, it means that the refractive power of the first lens group is too weak, the converging ability of the incident light is insufficient, and the subsequent lens group needs to bear stronger refractive power, thereby causing the increase of the curvature of the lens surface and the excessive bending of the structure, which not only increases the sensitivity to assembly errors, but also makes the aberration more difficult to control, and may also lead to the increase of the total length of the lens.

[0040] The second lens group in the embodiment of the present application has positive refractive power and is located in front of the aperture stop, which is complementary and cooperative with the first lens group to ensure the effective convergence of light. The second lens group as a focusing group can be translated along the optical axis to realize focusing function. In addition, the focal length of the second lens group and the focal length of the inner focus full-frame lens satisfy: 0.75≤F2 / F≤0.95, so that if the ratio of the focal length of the second lens group to the focal length of the inner focus wide-angle camera lens exceeds the lower limit, it indicates that the refractive power of the second lens group is too strong, and the strong refractive power will cause the image plane position to drift sharply, accompanied by significant changes in astigmatism and other aberrations, thereby it is difficult to maintain stable and uniform imaging quality in the entire focusing range. If the ratio of the focal length of the second lens group to the focal length of the inner focus full-frame lens exceeds the upper limit, it means that the refractive power of the second lens group is too weak, and the insufficient refractive power will lead to a longer optical axis moving distance to achieve clear imaging during focusing, so that the focusing stroke is too long and the focusing response speed is too slow, which will also weaken the aberration correction ability of the aspherical lens.

[0041] The third lens group in the embodiment of the present application has negative focal power, is the key to determine the total length and the flat field imaging of the lens, and the positive focal power of the second lens group and the third lens group form focal power cooperation, through the synergistic effect of positive and negative focal power, the physical length of the lens is effectively compressed under the premise of ensuring that the focal length of the lens meets the demand of the imaging field of view. In addition, the focal length of the third lens group and the focal length of the inner focusing full-frame lens meet: -1.10≤F3 / F≤-0.90, so if the ratio of the focal length of the third lens group to the focal length of the inner focusing wide-angle camera lens exceeds the lower limit, it means that the focal power of the third lens group is too strong, although it helps to further shorten the total optical length, but it will introduce too large Petzval sum, field curvature and distortion, which will seriously increase the difficulty of aberration correction, at the same time, it will also make the third lens group very sensitive to assembly tolerance. If the ratio of the focal length of the third lens group to the focal length of the inner focusing full-frame lens exceeds the upper limit, it means that the focal power of the third lens group is too weak, the effect of compressing the total length of the lens will be significantly weakened, in addition, it will also weaken the aberration correction function, making it difficult to effectively balance the residual aberration, so as to realize the high-quality flat field imaging effect.

[0042] In the embodiment of the present application, the total optical length of the inner focusing full-frame lens and the focal length of the inner focusing full-frame lens meet: 1.55≤TTL / F≤1.75, so if the ratio of the total optical length of the inner focusing full-frame lens to the focal length of the inner focusing full-frame lens exceeds the lower limit, it means that the total optical length is compressed too much, forcing the lens surface curvature to become abnormally steep, thereby causing a large number of uncontrolled high-order aberrations, such as high-order spherical aberration and high-order coma. These high-order aberrations cannot be effectively corrected by conventional optical design means, which will directly lead to a serious decline in imaging quality. If the ratio of the total optical length of the inner focusing full-frame lens to the focal length of the inner focusing full-frame lens exceeds the upper limit, it means that the total optical length is too large, which will directly lead to an increase in the size and weight of the lens, completely losing the core advantages of miniaturization and light weight.

[0043] The second lens group in the embodiment of the present application includes an aspherical lens located at the image side end of the second lens group. Integrating the aspherical lens in the movable focusing group realizes dynamic and accurate correction of aberration. Specifically, the aspherical lens arranged in the second lens group is located in a region with a large beam aperture, which can effectively correct on-axis and off-axis aberrations such as spherical aberration and coma. More importantly, during the focusing process, as the second lens group moves along the optical axis, the aspherical lens can continuously compensate for the aberration fluctuations caused by the change of the object distance, thereby maintaining stable high-quality imaging from infinity to the closest focusing distance. If the second lens group is not configured with an aspherical lens, it will be difficult to effectively suppress aberration variation during the focusing process, which may lead to a significant decline in image quality with the object distance. Generally, more complex lens structures or additional lenses need to be introduced, thereby increasing the cost and affecting the miniaturization design of the lens.

[0044] The third lens group in this embodiment includes an aspherical lens located at the object-side end of the third lens group. This aspherical lens functions at the position where the beam shape is smoothest, enabling efficient and accurate correction of image plane defects such as field curvature, distortion, and residual astigmatism. Furthermore, the incident angle of light at this position is small, allowing the aspherical lens's surface shape control capability to be fully utilized. A single aspherical lens can achieve the aberration correction effect that would otherwise require a combination of multiple spherical lenses, thus significantly simplifying the rear optical structure. This design is key to achieving a short back focal length and miniaturized overall lens length. If the third lens group does not include an aspherical lens, correcting the aforementioned aberrations would require a more complex rear lens configuration, increasing not only the number of lenses and the complexity of the combination but also leading to a significant increase in the overall optical length and lens weight.

[0045] In some embodiments, the first lens group includes at least one set of cemented doublet lenses, the cemented doublet lenses satisfying the following condition:

[0046] 15.0≤|Vd3-Vd4|≤22.0, (5);

[0047] Wherein, Vd3 represents the Abbe number of the first lens in the cemented doublet with respect to light with a wavelength of 587.6 nm, and Vd4 represents the Abbe number of the second lens in the cemented doublet with respect to light with a wavelength of 587.6 nm.

[0048] In this embodiment of the invention, if the difference between the Abbe number of the first lens and the Abbe number of the second lens in a cemented doublet is lower than the lower limit of 15.0, it indicates that the dispersion correction capability provided by the combination is insufficient, and it cannot effectively eliminate axial chromatic aberration and magnification chromatic aberration, resulting in obvious chromatic aberration at the image edges, which seriously affects the overall image clarity and color fidelity. Conversely, if the difference between the Abbe number of the first lens and the Abbe number of the second lens in a cemented doublet is higher than the upper limit of 22.0, it means that the dispersion characteristics of the two lenses are too different. Although theoretically this can bring stronger chromatic aberration correction capability, an excessively large Abbe number difference is often accompanied by a significant difference in the thermal expansion coefficient and refractive index temperature coefficient of the two lenses. This difference will generate excessive thermal stress when the ambient temperature changes, thereby significantly increasing the risk of delamination of the cemented surface. At the same time, an excessively large dispersion difference will also introduce a second-order spectrum that is difficult to correct, which will lead to a decrease in overall image quality.

[0049] In some embodiments, the first lens group includes at least one lens with an Abbe number Vd ≥ 75; and / or the first lens group includes at least one lens with a refractive index Nd ≥ 1.9. The high Abbe number lens is used to suppress the dispersion deviation of light of different wavelengths, eliminate color cast and color separation in the image, and ensure the accuracy of color reproduction. The high refractive index lens is used to improve the light refraction efficiency, significantly reduce the diameter of the lens and the aperture of the lens, and at the same time reduce stray light and improve the brightness and contrast of the image.

[0050] In this embodiment of the invention, if the first lens group is not equipped with a high Abbe number lens, it means that the average dispersion of this lens group is relatively high. This will introduce significant axial chromatic aberration at the front end. These primary chromatic aberrations will be transmitted to subsequent lens groups, greatly increasing the chromatic aberration correction burden of the middle and rear lens groups. This necessitates the use of more complex lens structures or the introduction of more special dispersion lenses, significantly increasing the manufacturing cost of the lens and potentially leading to an increase in the overall optical length and volume. If a lens group is not equipped with a high refractive index lens, in order to achieve the required optical power, a low refractive index lens with a smaller radius of curvature and a more curved surface must be used. This highly curved mirror surface will introduce a large number of difficult-to-correct higher-order aberrations such as spherical aberration and coma, severely restricting the improvement of image quality. At the same time, increasing the lens aperture directly leads to an increase in the weight and volume of the lens, which is not conducive to the development trend of lens miniaturization and lightweighting.

[0051] In some embodiments, the first lens group includes, from the object side to the image side, a first lens with positive optical power, a second lens with negative optical power, a third lens with negative optical power, and a fourth lens with positive optical power. Through the reasonable configuration of positive and negative optical powers, the first lens group can effectively balance aberrations such as spherical aberration and coma while bearing the main optical power of the system and suppressing image plane curvature.

[0052] In some embodiments, the refractive index Nd of the first lens is ≥1.9, the Abbe number Vd of the second lens is ≥75, and the third and fourth lenses are combined to form a first cemented lens. The first cemented lens composed of the third and fourth lenses can effectively cancel axial chromatic aberration and magnification chromatic aberration, suppress chromatic dispersion and chromatic aberration in imaging, and further balance monochromatic aberrations such as spherical aberration and coma through the synergistic effect of positive and negative optical power.

[0053] In some embodiments, the second lens group includes, from the object side to the image side, a fifth lens with negative optical power, a sixth lens with positive optical power, and a seventh lens with positive optical power.

[0054] In some embodiments, the fifth and sixth lenses are combined to form a second cemented lens, and the seventh lens is an aspherical lens. Both the fifth and sixth lenses have high refractive indices. Cementing these high-refractive-index and well-matched lenses together creates a powerful second cemented lens that significantly reduces axial chromatic aberration and spherical aberration, improves the accuracy of aberration correction, and facilitates miniaturization of the lens. The aspherical lens can further correct spherical aberration and coma.

[0055] In some embodiments, the third lens group comprises, in order from the object side to the image side, an eighth lens with negative refractive power and a parallel flat plate, the parallel flat plate arranged at the image side end mainly undertakes a protection function, effectively isolates the internal optical elements from the external environment without introducing additional aberrations, and improves the environmental adaptability and reliability of the entire lens.

[0056] In some embodiments, the eighth lens is an aspherical lens, which, through its unique surface morphology, can correct field curvature and distortion while efficiently undertaking the negative refractive power of the third lens group, thereby ensuring the flatness and geometric accuracy of the entire image.

[0057] The inner focusing full-frame lens in the present application cooperates with the reasonable refractive power distribution and the introduction of aspherical lenses to ensure high optical performance and compact structure, integrates an aspherical lens at the image side end of the second lens group with positive refractive power, corrects spherical aberration and coma by means of the special surface of the aspherical lens, sets another aspherical lens at the object side end of the third lens group with negative refractive power, effectively optimizes the control of astigmatism, distortion and field curvature, and through the synergistic effect of the two aspherical lenses, accurately corrects multiple aberrations while reducing the total number of lenses, balances the imaging quality and cost control, and also shortens the physical total length of the lens and reduces the volume and weight of the lens by arranging the third lens group close to the image plane to undertake negative refractive power and cooperating with the second lens group with positive refractive power to form a rear group structure similar to a telephoto lens, thereby realizing the design of super miniaturization.

[0058] The specific implementation of the present application is described in detail in combination with specific embodiments as follows:

[0059] Embodiment one:

[0060] Figure 1 A cross-sectional view of the inner focusing full-frame lens provided by the embodiment one of the present application in the Y-Z plane is shown. For ease of illustration, only the parts related to the embodiment of the present application are shown, and the details are as follows:

[0061] As Figure 1As shown, in this embodiment, the first lens group G1 includes, in order from the object side to the image side, a first lens L01 having positive refractive power, a second lens L02 having negative refractive power, a third lens L03 having negative refractive power, and a fourth lens L04 having positive refractive power, wherein the refractive index Nd1 of the first lens is 1.95, the Abbe number Vd2 of the second lens L02 is 81.60, the third lens L03 and the fourth lens L04 are combined into a first cemented lens. The second lens group G2 includes, in order from the object side to the image side, a fifth lens L05 having negative refractive power, a sixth lens L06 having positive refractive power, and a seventh lens L07 having positive refractive power, wherein the fifth lens L05 and the sixth lens L06 are combined into a second cemented lens, and the seventh lens L07 is an aspherical lens. The third lens group G3 includes, in order from the object side to the image side, an eighth lens L08 having negative refractive power and a parallel flat plate, and the eighth lens L08 is an aspherical lens.

[0062] The ratio of the focal length of the first lens group G1 to the focal length of the inner focusing full-frame lens F1 / F = 1.09, which satisfies the following conditional expression:

[0063] 1.00≤F1 / F≤1.20, (1) ;

[0064] The ratio of the focal length of the second lens group G2 to the focal length of the inner focusing full-frame lens F2 / F = 0.85, which satisfies the following conditional expression:

[0065] 0.75≤F2 / F≤0.95, (2) ;

[0066] The ratio of the focal length of the third lens group G3 to the focal length of the inner focusing full-frame lens F3 / F = -1.02, which satisfies the following conditional expression:

[0067] -1.10≤F3 / F≤-0.90, (3) ;

[0068] The ratio of the total optical length of the inner focusing full-frame lens TTL to the focal length of the inner focusing full-frame lens F TTL / F = 1.61, which satisfies the following conditional expression:

[0069] 1.55≤TTL / F≤1.75, (4) ;

[0070] The Abbe number of the third lens L03 is Vd3 = 28.32 for light having a wavelength of 587.6 nm, the Abbe number of the fourth lens L04 is Vd4 = 46.57 for light having a wavelength of 587.6 nm, which satisfies the following conditional expression:

[0071] 15.0≤|Vd3-Vd4|≤22.0, (5).

[0072] Figure 2 andFigure 3 The spherical aberration, field curvature and distortion curves of the embodiment one of the present application at infinity focus are shown. The spherical aberration curve at infinity focus represents the spherical aberration curve at the aperture number of 1.0, wherein the F line, the D line and the C line represent the spherical aberration at the wavelength of 486 nm, the wavelength of 587 nm and the wavelength of 656 nm respectively, the abscissa represents the spherical aberration value, and the ordinate represents the field of view. The field curvature curve represents the field curvature curve at the half field angle ω of 27.54°, wherein the dotted line S represents the value of the chief ray D line on the sagittal image plane, the solid line T represents the value of the chief ray D line on the tangential image plane, the abscissa represents the field curvature value, and the ordinate represents the field of view. The distortion curve represents the distortion curve at the half field angle ω of 27.54°, wherein the abscissa represents the distortion value, and the ordinate represents the field of view.

[0073] As shown in FIGS. 2-3, the photographic lens of the embodiment one of the present application has a good imaging effect.

[0074] In the embodiment, the specific numerical data of the inner focus full-frame lens are shown in Table 1-Table 3:

[0075] Table 1: Optical parameters of the embodiment one

[0076]

[0077] Each aspheric surface can be defined by, but not limited to, the following formula:

[0078]

[0079] Wherein, x is the distance height of the aspheric surface at the position of height h along the optical axis from the vertex of the aspheric surface; c is the paraxial curvature of the aspheric surface, c = 1 / R (i.e., the paraxial curvature c is the inverse of the curvature radius R in Table 1 above); k is the conic coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface.

[0080] Table 2 shows the conic coefficient K and the order coefficient of each aspheric surface.

[0081] Table 2:

[0082]

[0083] Table 3: Focus data of the embodiment one

[0084]

[0085] The present application also provides an image pickup device, comprising an image sensor and an inner focus full-frame lens as described above, wherein the image sensor is configured to receive an optical image formed by the inner focus full-frame lens.

[0086] The above embodiments are only used to illustrate the technical solutions of the present application, and not intended to limit the present application. Even though the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the disclosed range of the foregoing embodiments is not limited to the technical solutions formed by the specific combinations of the technical features, and should also cover other technical solutions formed by the combinations of the technical features or their equivalent features without departing from the concept disclosed above. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

[0087] Further, while operations are depicted in a particular order, this should not be understood as requiring the operations to be performed in the particular order shown or in sequential order, and that certain operations can be performed in parallel or concurrently. Also, described certain features can also be implemented as software modules. Various functions of the same can be split into different modules or combined into sub-modules. In addition, the specific sequence of operations is not an essential feature or method of the application, and the sequence of operations can be changed.

Claims

1. An internal focusing full-frame lens characterized by comprising: From the object side to the image side, the inner focusing full-frame lens is sequentially composed of a first lens group with positive refractive power, an aperture stop, a second lens group with positive refractive power, and a third lens group with negative refractive power, the second lens group comprises an aspherical lens located at the image side end of the second lens group, the third lens group comprises an aspherical lens located at the object side end of the third lens group, the first lens group is sequentially composed of a first lens with positive refractive power, a second lens with negative refractive power, a third lens with negative refractive power, and a fourth lens with positive refractive power from the object side to the image side, the second lens group is sequentially composed of a fifth lens with negative refractive power, a sixth lens with positive refractive power, and a seventh lens with positive refractive power from the object side to the image side, the third lens group is sequentially composed of an eighth lens with negative refractive power and a parallel flat plate from the object side to the image side, and during the focusing process of the inner focusing full-frame lens, the second lens group moves from the object side to the image side to achieve focusing. The inner focusing full-frame lens satisfies the following conditional expressions: 1.00≤F1 / F≤1.20, (1); 0.75≤F2 / F≤0.95, (2); -1.10≤F3 / F≤-0.90, (3); 1.55≤TTL / F≤1.75, (4); wherein F1 represents the focal length of the first lens group, F2 represents the focal length of the second lens group, F3 represents the focal length of the third lens group, TTL represents the total optical length of the inner focusing full-frame lens, and F represents the focal length of the inner focusing full-frame lens.

2. The internal focus full-frame lens according to claim 1, characterized by, The first lens group comprises at least one set of double cemented lenses, and the double cemented lenses satisfy the following conditional expressions: 15.0≤|Vd3-Vd4|≤22.0, (5); wherein Vd3 represents the Abbe number of the first lens in the double cemented lens, and Vd4 represents the Abbe number of the second lens in the double cemented lens.

3. The internal focus full-frame lens of claim 1, wherein, The first lens group comprises at least one lens with an Abbe number Vd≥75; and / or The first lens group comprises at least one lens with a refractive index Nd≥1.

9.

4. The internal focus full-frame lens of claim 1, wherein, The refractive index of the first lens Nd≥1.9, the Abbe number of the second lens Vd≥75, and the third lens and the fourth lens are combined into a first cemented lens.

5. The internal focus full-frame lens of claim 1, wherein, The fifth lens and the sixth lens are combined into a second cemented lens, and the seventh lens is an aspherical lens.

6. The internal focus full-frame lens of claim 1, wherein, The eighth lens is an aspherical lens.

7. An image pickup device, characterized by comprising: An image sensor and an inner focusing full-frame lens according to any one of claims 1 to 6 are included, and the image sensor is configured to receive an optical image formed by the inner focusing full-frame lens.

Images