Ultra-large aperture standard focal length full-frame camera lens

Abstract

The invention discloses a full-frame camera lens with an ultra-large aperture and a standard focal length. The full-frame camera lens sequentially comprises a first lens group, an iris diaphragm, a second lens group and a third lens group from an object side to an imaging surface, the first lens group serves as a fixed group, has positive focal power and comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens; the second lens group is used as a focusing group and has negative focal power, and when the second lens group is focused from infinity to a near position, the second lens group is used as a focusing compensation group to move towards an imaging surface; according to the invention, aberration is effectively corrected, excellent performance can be obtained while the F1.4 maximum aperture is realized, imaging is excellent at infinity and close-up distance, and part of ghosting in a picture is effectively eliminated through calculation; the structure is short and light, the moving group only comprises two lenses, the weight and the moving stroke of the moving group are obviously reduced, and the focusing efficiency is effectively guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of camera lenses, and in particular to an ultra-large aperture standard focal length full-frame camera lens. Background Art

[0002] The amount of light entering the lens is an important parameter that affects the photographer's film success rate and picture quality. A large amount of light entering can shorten the exposure time, thereby bringing about stable and reliable film success. The amount of light entering the lens is expressed by the aperture value. A smaller aperture value can not only bring a larger amount of light entering, but also bring a shallower depth of field. Currently, the maximum aperture number of full-frame large aperture lenses on the market is generally F1.8, and super-large aperture lenses above F1.8 still have the disadvantages of being expensive and bulky. Therefore, the present invention designs a super-large aperture full-frame camera lens to improve the above problems. Summary of the invention

[0003] In view of the deficiencies in the prior art, the purpose of the present invention is to provide an ultra-large aperture standard focal length full-frame camera lens that can effectively correct aberrations, achieve superior performance, effectively eliminate some ghost images in the picture through calculation, have a short and lightweight structure, significantly reduce the weight and travel of the moving group, and effectively ensure focusing efficiency.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A super-large aperture standard focal length full-frame camera lens, comprising a first lens group, a variable aperture, a second lens group and a third lens group in order from the object side to the imaging surface;

[0006] The first lens group is a fixed group with positive optical power, and includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens;

[0007] The second lens group serves as a focusing group, has negative optical power, and includes a ninth lens and a tenth lens. When focusing from infinity to near, the second lens group serves as a focus compensation group and moves toward the imaging plane;

[0008] The third lens group is a fixed group with positive power, and includes an eleventh lens, a twelfth lens, a thirteenth lens and a fourteenth lens;

[0009] The first lens group contains a biconvex air spacer, which satisfies the following conditions:

[0010] -0.5<(A3R2+A3R1) / (A3R2-A3R1)<1.5

[0011] Wherein, A3R1 is the curvature radius of a side surface of the biconvex air space in the first lens group close to the object side, and A3R2 is the curvature radius of a side surface of the biconvex air space in the first lens group close to the imaging surface.

[0012] Preferably, the first lens is a negative meniscus lens curved toward the image plane, satisfying the following conditions:

[0013] -4<(G1R2+G1R1) / (G1R2-G1R1)<-2

[0014] Wherein, G1R1 is the curvature radius of the side surface of the first lens close to the object side, and G1R2 is the curvature radius of the side surface of the first lens close to the imaging surface.

[0015] Preferably, the first lens group includes a biconvex aspheric glass lens that meets the following conditions:

[0016] 0.8 <f / F5<2.8

[0017] Among them, F5 is the focal length of the biconvex aspheric glass lens of the first lens group, and f is the focal length of the camera lens optical system.

[0018] Preferably, the second lens group is composed of a biconcave lens and a biconvex lens, satisfying the following conditions:

[0019] 1<|F10| / |F9|<3

[0020] Wherein, F9 is the focal length of the biconcave lens in the second lens group, and F10 is the focal length of the biconvex lens in the second lens group.

[0021] Preferably, the third lens group contains a biconvex air spacer, which satisfies the following conditions:

[0022] -0.5<(A12R2+A12R1) / (A12R2-A12R1)<1.5

[0023] Wherein, A12R1 is the curvature radius of a side surface of the biconvex air space in the third lens group close to the object side, and A12R2 is the curvature radius of a side surface of the biconvex air space in the third lens group close to the imaging surface.

[0024] Preferably, the last lens in the third lens group meets the following conditions:

[0025] -4 <F14 / f<-2

[0026] -2.5 <F14 / FG3<-0.5

[0027] Among them, F14 is the focal length of the last lens in the third lens group, FG3 is the focal length of the third lens group, and f is the focal length of the camera lens optical system.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention uses positive and negative lenses and aspherical lenses to effectively correct aberrations, and can achieve excellent performance while achieving a maximum aperture of F1.4. It has excellent imaging at infinity and close shooting distances, and can effectively eliminate some ghost images in the picture through calculation. The structure is short and lightweight, and the moving group contains only two lenses, which significantly reduces the weight and moving stroke of the moving group, and the focusing efficiency is effectively guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the lens structure of a super-large aperture standard focal length full-frame camera lens;

[0031] Figure 2 This is the spherical aberration curve of the ultra-large aperture standard focal length full-frame camera lens;

[0032] Figure 3 This is a graph of the field curvature of a full-frame camera lens with a large aperture and standard focal length;

[0033] Figure 4 This is the distortion curve of a full-frame camera lens with a super large aperture and standard focal length.

[0034] In the figure: G1, first lens group; G2, second lens group; G3, third lens group; 1, first lens; 2, second lens; 3, third lens; 4, fourth lens; 5, fifth lens; 6, sixth lens; 7, seventh lens; 8, eighth lens; 9, ninth lens; 10, tenth lens; 11, eleventh lens; 12, twelfth lens; 13, thirteenth lens; 14, fourteenth lens. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0036] Example:

[0037] See also Figure 1 , this embodiment provides a super large aperture standard focal length full-frame camera lens, which includes a first lens group G1, a variable aperture, a second lens group G2 and a third lens group G3 in sequence from the object side to the imaging surface;

[0038] The first lens group G1 is a fixed group with negative optical power, including a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7 and an eighth lens 8, wherein the fifth lens 5 is an aspherical lens;

[0039] The second lens group G2 is a focus group having negative optical power, and includes a ninth lens 9 and a tenth lens 10. When focusing from infinity to near, the second lens group G2 moves toward the imaging plane as a focus compensation group (moving group);

[0040] The third lens group G3 is a fixed group with positive power, and includes an eleventh lens 11, a twelfth lens 12, a thirteenth lens 13 and a fourteenth lens 14. The eleventh lens 11 and the fourteenth lens 14 are aspherical lenses. The number of lenses in the first lens group G1, the second lens group G2 and the third lens group G3 is designed according to design and use requirements, and increasing or decreasing the number of lenses belongs to the protection scope of the present invention.

[0041] The first lens group G1 contains a biconvex air spacer, which satisfies the following conditions:

[0042] -0.5<(A3R2+A3R1) / (A3R2-A3R1)<1.5

[0043] A3R1 is the curvature radius of the side surface of the biconvex air space in the first lens group G1 close to the object side, and A3R2 is the curvature radius of the side surface of the biconvex air space in the first lens group G1 close to the imaging surface.

[0044] In this embodiment, the first lens 1 is a negative meniscus lens curved toward the image plane, satisfying the following conditions:

[0045] -4<(G1R2+G1R1) / (G1R2-G1R1)<-2

[0046] Wherein, G1R1 is the curvature radius of the side surface of the first lens 1 close to the object side, and G1R2 is the curvature radius of the side surface of the first lens 1 close to the imaging surface.

[0047] In this embodiment, the first lens group G1 includes a biconvex aspheric glass lens that meets the following conditions:

[0048] 0.8 <f / F5<2.8

[0049] Among them, F5 is the focal length of the biconvex aspheric glass lens of the first lens group G1, and f is the focal length of the camera lens optical system.

[0050] In this embodiment, the second lens group G2 is composed of a biconcave lens and a biconvex lens, and satisfies the following conditions:

[0051] 1<|F10| / |F9|<3

[0052] Among them, F9 is the focal length of the biconcave lens in the second lens group G2, and F10 is the focal length of the biconvex lens in the second lens group G2.

[0053] In this embodiment, the third lens group G3 contains a biconvex air spacer, which satisfies the following conditions:

[0054] -0.5<(A12R2+A12R1) / (A12R2-A12R1)<1.5

[0055] Wherein, A12R1 is the curvature radius of a side surface of the biconvex air space in the third lens group G3 close to the object side, and A12R2 is the curvature radius of a side surface of the biconvex air space in the third lens group G3 close to the imaging surface.

[0056] In this embodiment, the last lens (i.e., the fourteenth lens 14) in the third lens group G3 satisfies the following conditions:

[0057] -4 <F14 / f<-2

[0058] -2.5 <F14 / FG3<-0.5

[0059] Wherein, F14 is the focal length of the last lens (fourteenth lens 14) in the third lens group G3, FG3 is the focal length of the third lens group G3, and f is the focal length of the camera lens optical system.

[0060] As a preferred embodiment of the technical solution of this embodiment, the parameters of the camera lens embodiment are shown in Table 1 below, wherein the aspheric coefficients of the aspheric lens are shown in Table 2 below, and the surface number column shows the surface number when the surface close to the object side is set as the first surface and the surface number is increased one by one toward the imaging surface side, and the shape parameters of each lens are:

[0061] Table 1

[0062]

[0063]

[0064] Table 2

[0065]

[0066] As a preferred technical solution, the positions of the focus compensation group (moving group) of the camera lens in different focus states in this embodiment are shown in Table 3 below, which are the values ​​of the two states of D1 and D2 in Table 1:

[0067] Table 3

[0068] Conjugate distance Infinity Closest (0.5m) D1 3.7mm 13.15mm D2 10.55mm 1.1mm

[0069] As a preferred technical solution, the physical parameters of the camera lens in this embodiment are shown in Table 4 below:

[0070] Table 4

[0071] Focal length f 48.24mm Relative aperture FNO. 1.45 Field of viewω 41.6° Total optical length 122mm

[0072] Figure 2 is a spherical aberration curve diagram of the camera lens in this embodiment, Figure 3 is a field curvature curve diagram of the camera lens in this embodiment, Figure 4 is a distortion curve diagram of the camera lens in this embodiment. It can be seen that the camera lens in this embodiment has a good imaging effect.

[0073] In this embodiment, through the limitation of the above-mentioned conditional formula, the aberration is effectively corrected by using the combination of positive and negative lenses and aspherical lenses. While achieving the maximum aperture of F1.4, excellent performance can be obtained, and imaging is excellent at infinity and close shooting distances. Some ghost images in the picture are effectively eliminated through calculation; the structure is short and lightweight, and the moving group contains only two lenses, which significantly reduces the weight and moving stroke of the moving group, and the focusing efficiency is effectively guaranteed.

[0074] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present technical solution is within the protection scope of the present invention.

Claims

1. A super large aperture standard focal length full-frame camera lens, characterized by: From the object side to the imaging surface, it includes a first lens group (G1), a variable aperture, a second lens group (G2) and a third lens group (G3); The first lens group (G1) is a fixed group with positive refractive power, comprising a first lens (1), a second lens (2), a third lens (3), a fourth lens (4), a fifth lens (5), a sixth lens (6), a seventh lens (7) and an eighth lens (8); The second lens group (G2) serves as a focusing group and has negative optical power, and includes a ninth lens (9) and a tenth lens (10). When focusing from infinity to near, the second lens group (G2) serves as a focus compensation group and moves toward the imaging plane; The third lens group (G3) is a fixed group with positive refractive power, and includes an eleventh lens (11), a twelfth lens (12), a thirteenth lens (13) and a fourteenth lens (14); The first lens group (G1) contains a biconvex air spacer, which satisfies the following conditions: -0.5<(A3R2+A3R1) / (A3R2-A3R1)<1.5 Wherein, A3R1 is the curvature radius of a side surface of the biconvex air space in the first lens group (G1) close to the object side, and A3R2 is the curvature radius of a side surface of the biconvex air space in the first lens group (G1) close to the imaging surface.

2. The ultra-large aperture standard focal length full-frame camera lens according to claim 1, characterized in that: The first lens (1) is a negative meniscus lens curved toward the image plane and meets the following conditions: -4<(G1R2+G1 R1) / (G1R2-G1R1)<-2 Wherein, G1R1 is the curvature radius of the side surface of the first lens (1) close to the object side, and G1R2 is the curvature radius of the side surface of the first lens (1) close to the imaging surface.

3. The ultra-large aperture standard focal length full-frame camera lens according to claim 1, characterized in that: The first lens group (G1) includes a biconvex aspheric glass lens that meets the following conditions: 0.8 <f / F5<2.8 Among them, F5 is the focal length of the biconvex aspheric glass lens of the first lens group (G1), and f is the focal length of the camera lens optical system.

4. The ultra-large aperture standard focal length full-frame camera lens according to claim 1, characterized in that: The second lens group (G2) is composed of a biconcave lens and a biconvex lens, and meets the following conditions: 1<|F10| / |F9|<3 Among them, F9 is the focal length of the biconcave lens in the second lens group (G2), and F10 is the focal length of the biconvex lens in the second lens group (G2).

5. The ultra-large aperture standard focal length full-frame camera lens according to claim 1, characterized in that: The third lens group (G3) contains a biconvex air spacer, which satisfies the following conditions: -0.5<(A12R2+A12R1) / (A12R2-A12R1)<1.5 Wherein, A12R1 is the curvature radius of a side surface of the biconvex air space in the third lens group (G3) close to the object side, and A12R2 is the curvature radius of a side surface of the biconvex air space in the third lens group (G3) close to the imaging surface.

6. The ultra-large aperture standard focal length full-frame camera lens according to claim 1, characterized in that: The last lens in the third lens group (G3) satisfies the following conditions: -4 <F14 / f<-2 -2.5 <F14 / FG3<-0.5 Among them, F14 is the focal length of the last lens in the third lens group (G3), FG3 is the focal length of the third lens group (G3), and f is the focal length of the camera lens optical system.

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