Medium-and-long-focus full-frame lens

Abstract

The utility model discloses a full-frame lens with medium and long focal lengths. The full-frame lens comprises a first lens group, a second lens group, a third lens group and a fourth lens group which are sequentially arranged from an object side to an image side along an optical axis, wherein the combined focal lengths of all the lens groups meet the following conditional expressions: 1.5 < f (G1) / f < 3.3; f (G2-G4) / f is more than 0.7 and less than 1.5; f (G3) / f (G2-G4) is greater than-1 and less than-0.5; wherein f (G1) is the combined focal length of the first lens group, f (G2-G4) is the combined focal length of the second lens group, the third lens group and the fourth lens group, f (G3) is the combined focal length of the third lens group, and f is the combined focal length of all the lens groups. The full-frame lens with the medium and long focal lengths corrects various aberrations of various wave bands, enables a central view field and an edge view field to have enough resolution, has the advantages of being simple in structure, small in size and large in aperture, and can achieve high resolution of imaging with the object distance from infinity to close distance.

Description

Technical Field

[0001] The utility model relates to the technical field of optical lenses, and particularly relates to a medium and long focal length full-frame lens. Background Art

[0002] In recent years, although the multi-functions of mobile phones have replaced the daily photography of compact cameras, in the view of photography enthusiasts with higher photography requirements, mirrorless cameras can better experience the perfect photography pleasure. The lenses of mirrorless cameras have the advantages of small size, light weight, convenient carrying, larger image plane and aperture, etc., and can experience a better background blur effect.

[0003] Existing medium and long focal length full-frame lenses have problems of various aberrations and low resolution in the imaging of some wavelength bands. Summary of the Utility Model

[0004] Therefore, the technical problem to be solved by the utility model is to overcome the defects that existing medium and long focal length full-frame lenses have various aberrations and low resolution in the imaging of some wavelength bands, so as to provide a medium and long focal length full-frame lens.

[0005] To solve the above technical problem, the technical solution of the utility model is as follows:

[0006] A medium and long focal length full-frame lens, including a first lens group, a second lens group, a third lens group, and a fourth lens group arranged in sequence along the optical axis from the object side to the image side: the combined focal lengths of all lens groups satisfy the following conditional expressions:

[0007] 1.5 < f(G1) / f < 3.3;

[0008] 0.7 < f(G2 - G4) / f < 1.5;

[0009] -1 < f(G3) / f(G2 - G4) < -0.5;

[0010] Wherein, f(G1) is the combined focal length of the first lens group, f(G2 - G4) is the combined focal length of the second lens group, the third lens group, and the fourth lens group, f(G3) is the combined focal length of the third lens group, and f is the combined focal length of all lens groups.

[0011] Further, a diaphragm is provided between the first lens group and the second lens group, and the third lens group can move along the direction of the optical axis to achieve focusing.

[0012] Further, the first lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged in sequence along the optical axis from the object side to the image side;

[0013] The first lens is a meniscus lens with a positive optical power and a convex surface facing the object surface;

[0014] The second lens is a meniscus lens with a positive refractive power and a convex surface facing the object surface;

[0015] The third lens is a meniscus lens with a positive refractive power and a convex surface facing the object surface;

[0016] The fourth lens is a meniscus lens with a negative refractive power and a convex surface facing the object surface.

[0017] Wherein, the side surfaces of the third lens and the fourth lens that are in contact are glued together.

[0018] Further, the second lens group includes a fifth lens; the fifth lens is a meniscus lens with a positive refractive power and a convex surface facing the object surface.

[0019] Further, the third lens group includes a sixth lens; the sixth lens is a meniscus lens with a negative refractive power and a convex surface facing the object surface.

[0020] Further, the fourth lens group includes a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, and a fourteenth lens arranged in sequence along the optical axis from the object side to the image side;

[0021] The seventh lens is a meniscus lens with a negative refractive power and a convex surface facing the object surface;

[0022] The eighth lens is a meniscus lens with a positive refractive power and a convex surface facing the object surface;

[0023] The ninth lens is a biconcave lens with a negative refractive power;

[0024] The tenth lens is a biconvex lens with a positive refractive power;

[0025] The eleventh lens is a biconvex lens with a positive refractive power;

[0026] The twelfth lens is a biconcave lens with a negative refractive power;

[0027] The thirteenth lens is a meniscus lens with a positive refractive power and a convex surface facing the image surface;

[0028] The fourteenth lens is a biconcave lens with a negative refractive power.

[0029] Wherein, the side surfaces of the seventh lens and the eighth lens that are in contact are glued together, the side surfaces of the ninth lens and the tenth lens that are in contact are glued together, the side surfaces of the eleventh lens and the twelfth lens that are in contact are glued together, and the side surfaces of the thirteenth lens and the fourteenth lens that are in contact are glued together.

[0030] Further, the object side surfaces and the image side surfaces of all the lenses among the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, and the fourteenth lens facing the object side are spherical surfaces; the object side surface of the thirteenth lens facing the object side is an aspherical surface, and the image side surface of the thirteenth lens facing the image side is a spherical surface.

[0031] Further, the aperture of the medium telephoto full-frame lens is 1 - 1.6, and the focal length of the medium telephoto full-frame lens is 70 - 90 mm.

[0032] Further, the overall optical length of the medium telephoto full-frame lens does not exceed 115 mm.

[0033] The advantages of the medium telephoto full-frame lens provided by the present utility model are that various aberrations in each wavelength band are corrected, sufficient resolution is achieved in both the central and peripheral fields of view, it has the advantages of simple structure, small volume, and large aperture, and high resolution imaging can be realized for object distances from infinity to close range. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0035] Figure 1 It is a schematic cross-sectional structure diagram of the medium telephoto full-frame lens in the embodiment of the present utility model;

[0036] Figure 2 It is the field curvature and distortion diagram of the medium telephoto full-frame lens in the embodiment of the present utility model.

[0037] Description of the reference numerals: G1, the first lens group; G2, the second lens group; G3, the third lens group; G4, the fourth lens group; 1, the first lens; 2, the second lens; 3, the third lens; 4, the fourth lens; 5, the fifth lens; 6, the sixth lens; 7, the seventh lens; 8, the eighth lens; 9, the ninth lens; 10, the tenth lens; 11, the eleventh lens; 12, the twelfth lens; 13, the thirteenth lens; 14, the fourteenth lens. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] The technical solution of the present utility model will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are some but not all of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0039] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0040] As Figure 1 shown in FIG. -2, a medium and long focal length full-frame lens includes a first lens group G1, a second lens group G2, a third lens group G3, and a fourth lens group G4 sequentially arranged along the optical axis from the object side to the image side. The combined focal length of all lens groups satisfies the following conditional expressions:

[0041] 1.5 < f(G1) / f < 3.3;

[0042] 0.7 < f(G2 - G4) / f < 1.5;

[0043] -1 < f(G3) / f(G2 - G4) < -0.5;

[0044] Wherein, f(G1) is the combined focal length of the first lens group G1, f(G2 - G4) is the combined focal length of the second lens group G2, the third lens group G3, and the fourth lens group G4, fG3 is the combined focal length of the third lens group G3, and f is the combined focal length of all lens groups.

[0045] In this embodiment, the first lens group G1 includes a first lens 1, a second lens 2, a third lens 3, and a fourth lens 4 arranged in sequence from the object side to the image side along the optical axis. The first lens 1 is a meniscus lens with a positive focal power and a convex surface facing the object surface; the second lens 2 is a meniscus lens with a positive diopter and a convex surface facing the object surface; the third lens 3 is a meniscus lens with a positive diopter and a convex surface facing the object surface; the fourth lens 4 is a meniscus lens with a negative diopter and a convex surface facing the object surface. The second lens group G2 includes a fifth lens 5; the fifth lens 5 is a meniscus lens with a positive diopter and a convex surface facing the object surface. The third lens group G3 includes a sixth lens 6; the sixth lens 6 is a meniscus lens with a negative diopter and a convex surface facing the object surface. The fourth lens group G4 includes a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10, an eleventh lens 11, a twelfth lens 12, a thirteenth lens 13, and a fourteenth lens 14; the seventh lens 7 is a meniscus lens with a negative diopter and a convex surface facing the object surface; the eighth lens 8 is a meniscus lens with a positive diopter and a convex surface facing the object surface; the ninth lens 9 is a biconcave lens with a negative diopter; the tenth lens 10 is a biconvex lens with a positive diopter; the eleventh lens 11 is a biconvex lens with a positive diopter; the twelfth lens 12 is a biconcave lens with a negative diopter; the thirteenth lens 13 is a meniscus lens with a positive diopter and a convex surface facing the image surface; the fourteenth lens 14 is a biconcave lens with a negative diopter.

[0046] Among them, the side surfaces where the third lens 3 and the fourth lens 4 are in contact are glued together, the side surfaces where the seventh lens 7 and the eighth lens 8 are in contact are glued together, the side surfaces where the ninth lens 9 and the tenth lens 10 are in contact are glued together, the side surfaces where the eleventh lens 11 and the twelfth lens 12 are in contact are glued together, and the side surfaces where the thirteenth lens and the fourteenth lens 14 are in contact are glued together. The glued lens combination can effectively correct chromatic aberration and make the color of the captured image more realistic.

[0047] In this embodiment, a diaphragm is provided between the first lens group G1 and the second lens group G2, and the third lens group G3 can move along the direction of the optical axis to achieve focusing. Only a single lens in the third lens group G3 is used to achieve the focusing function, and the focusing operation is more convenient and simple.

[0048] In this embodiment, the object side surfaces and the image side surfaces of all the lenses in the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the ninth lens 9, the tenth lens 10, the eleventh lens 11, the twelfth lens 12, and the fourteenth lens 14 facing the object side are spherical surfaces; the object side surface of the thirteenth lens 13 facing the object side is an aspherical surface, and the image side surface of the thirteenth lens 13 facing the image side is a spherical surface. With such a setting, spherical aberration, field curvature and other aberrations can be effectively corrected, and the overall weight of the lens can be reduced.

[0049] In this embodiment, the aperture of the medium telephoto full-frame lens is 1 - 1.6, and the focal length of the medium telephoto full-frame lens is 70 - 90 mm. The overall optical length of the medium telephoto full-frame lens does not exceed 115 mm.

[0050] Among them, the relevant parameters of each lens are shown in Table 1 below:

[0051]

[0052] Table 1

[0053] The aspherical coefficients of the thirteenth lens are shown in Table 2 below:

[0054] Thirteenth lens Aspherical surface K 0 A4 －4.19409E－06 A6 －8.09531E－10 A8 5.91892E－12 A10 －2.3495E－14 A12 6.14834E－18 A14 2.40936E－20

[0055] Table 2

[0056] As Figure 1 shown, in the embodiment, the sixth lens 6 can perform internal focusing between the fifth lens 5 and the seventh lens 7 along the optical axis direction. Therefore, when the lens adjusts the focal length, the overall length of the lens can be kept unchanged.

[0057] This medium telephoto full-frame lens corrects various aberrations in each wavelength band, enabling sufficient resolution in both the central and peripheral fields of view. It has the advantages of simple structure, small size, and large aperture, and can achieve high resolution for imaging with object distances ranging from infinity to close range.

[0058] From Figure 2 it can be seen that the field curvatures in the meridional (corresponding to T in Figure 2 ) and sagittal (corresponding to S in Figure 2 ) directions generated by the medium telephoto full-frame lens for light are between -0.2 mm and 0.2 mm; the maximum distortion of the crop-frame lens is within 10%.

[0059] It should be noted that this medium telephoto full-frame lens adopts an integrated design, achieving excellent optical performance with high resolution, low breathing, and low distortion while miniaturizing the lens. It can be designed to match the mounts of various brands of cameras according to actual usage requirements to achieve personalized customization and general compatibility.

[0060] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of this utility model creation.

Claims

1. A medium-telephoto full-frame lens, characterized in that: The invention comprises a first lens group (G1), a second lens group (G2), a third lens group (G3) and a fourth lens group (G4) which are arranged in sequence from the object side to the image side along the optical axis: the combined focal length of all lens groups satisfies the following conditions: 1.5<f(G1) / f<3.3; 0.7<f(G2-G4) / f<1.5; -1<f(G3) / f(G2-G4)<-0.5; wherein, f(G1) is the combined focal length of the first lens group (G1), f(G2-G4) is the combined focal length of the second lens group (G2), the third lens group (G3) and the fourth lens group (G4), f(G3) is the combined focal length of the third lens group (G3), and f is the combined focal length of all lens groups.

2. The medium-long focal length full-frame lens according to claim 1, characterized in that: An aperture is provided between the first lens group (G1) and the second lens group (G2), and the third lens group (G3) can move along the direction of the optical axis to achieve focusing.

3. The medium-long focal length full-frame lens according to claim 1, characterized in that: The first lens group (G1) comprises a first lens (1), a second lens (2), a third lens (3), and a fourth lens (4) which are arranged in sequence from the object side to the image side along the optical axis; The first lens (1) is a meniscus lens with positive focal power and a convex surface facing the object plane; The second lens (2) is a positive-power meniscus lens with a convex surface facing the object plane; The third lens (3) is a positive refractive power meniscus lens with the convex surface facing the object plane; The fourth lens (4) is a meniscus lens with negative refractive power and a convex surface facing the object plane; Wherein, the side surfaces where the third lens (3) and the fourth lens (4) meet are glued together.

4. The medium-telephoto full-frame lens according to claim 1, characterized in that: The second lens group (G2) comprises a fifth lens (5); the fifth lens (5) is a meniscus lens with positive refractive power and a convex surface facing the object plane.

5. The medium-long focal length full-frame lens according to claim 1, characterized in that: The third lens group (G3) comprises a sixth lens (6); the sixth lens (6) is a meniscus lens with a negative refractive power and a convex surface facing the object plane.

6. The medium-long focal length full-frame lens according to claim 3, characterized in that: The fourth lens group (G4) comprises a seventh lens (7), an eighth lens (8), a ninth lens (9), a tenth lens (10), an eleventh lens (11), a twelfth lens (12), a thirteenth lens (13) and a fourteenth lens (14) which are arranged in sequence from the object side to the image side along the optical axis; The seventh lens (7) is a meniscus lens with negative refractive power and a convex surface facing the object plane; The eighth lens (8) is a positive refractive power meniscus lens with the convex surface facing the object plane; The ninth lens (9) is a biconcave lens with negative refractive power; The tenth lens (10) is a biconvex lens with positive refractive power; The eleventh lens (11) is a biconvex lens with positive refractive power; The twelfth lens (12) is a biconcave lens with negative refractive power; The thirteenth lens (13) is a positive refractive power meniscus lens with the convex surface facing the image plane; The fourteenth lens (14) is a biconcave lens with negative refractive power; The side surfaces of the seventh lens (7) and the eighth lens (8) are glued together, the side surfaces of the ninth lens (9) and the tenth lens (10) are glued together, the side surfaces of the eleventh lens (11) and the twelfth lens (12) are glued together, and the side surfaces of the thirteenth lens and the fourteenth lens (14) are glued together.

7. The medium-long focal length full-frame lens according to claim 6, characterized in that: The object side surfaces of all the lenses of the first lens (1), the second lens (2), the third lens (3), the fourth lens (4), the fifth lens (5), the sixth lens (6), the seventh lens (7), the eighth lens (8), the ninth lens (9), the tenth lens (10), the eleventh lens (11), the twelfth lens (12) and the fourteenth lens (14) facing the object side and the image side surfaces facing the image side are spherical surfaces; the object side surface of the thirteenth lens (13) facing the object side is an aspherical surface, and the image side surface of the thirteenth lens (13) facing the image side is a spherical surface.

8. The medium-long focal length full-frame lens according to claim 1, characterized in that: The aperture of the medium-long focal length full-frame lens is 1-1.6, and the focal length of the medium-long focal length full-frame lens is 70-90 mm.

9. The medium-long focal length full-frame lens according to claim 1, characterized in that: The total optical length of the medium-telephoto full-frame lens does not exceed 115 mm.

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