Wide-angle ultra-large-aperture full-frame camera lens

Abstract

The invention discloses a wide-angle ultra-large-aperture full-frame camera lens which sequentially comprises a first lens group, a second lens group, an iris diaphragm, a third lens group and a fourth lens group from an object side to an imaging plane, the first lens group serves as a fixed group, has negative focal power and comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens, and the second lens group serves as a fixed group. The second lens group serves as a focusing group, has negative focal power and comprises a sixth lens, and when the second lens group is focused from the infinity to the near position, the second lens group serves as a focusing compensation group to move towards the object space; according to the invention, aberration is effectively corrected, F1.4 maximum aperture is realized, excellent performance can be obtained, imaging at infinity and close-up distance is excellent, part of ghosting in a picture is effectively eliminated through calculation, distortion is less than 2%, the structure is short, small and light, a moving group only comprises one lens, the weight and moving stroke of the moving group are obviously reduced, and the moving group is more compact and compact. And the focusing efficiency is effectively ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of camera lenses, and in particular to a wide-angle, ultra-large aperture, full-frame camera lens. Background Art

[0002] Night scene photography and starry sky photography have always been popular subjects in the photography industry, but due to the low light level at night, the images obtained will mostly have noise or blur due to long exposure. Therefore, such photographers need to choose a lens with a large enough aperture to meet the requirements for image clarity and cleanliness. Currently, the maximum aperture number of full-frame large aperture lenses on the market is generally F1.8, and ultra-large aperture lenses above F1.8 still have the disadvantages of being expensive and bulky. Therefore, the present invention designs a wide-angle ultra-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 a wide-angle, ultra-large aperture, full-frame camera lens that can effectively correct aberrations, greatly reduce the discomfort of video shooting, improve the photography experience, has a short and lightweight structure, significantly reduces the weight and moving range of the moving group, and effectively guarantees the focusing efficiency.

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

[0005] A wide-angle ultra-large aperture full-frame camera lens, comprising, from the object side to the imaging surface, a first lens group, a second lens group, a variable aperture, a third lens group and a fourth lens group;

[0006] The first lens group is a fixed group with negative optical power, and includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens;

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

[0008] The third lens group is a fixed group with positive power, and includes a seventh lens, an eighth lens, a ninth lens, a tenth lens and an eleventh lens;

[0009] The fourth lens group includes a twelfth lens, a thirteenth lens, a fourteenth lens and a fifteenth lens.

[0010] Preferably, the first lens and the second lens are negative meniscus lenses curved toward the image plane, satisfying the following conditions:

[0011] D1>7mm

[0012] 1.31 <F2 / F1<2.52

[0013] Wherein, D1 is the center distance between the first lens and the second lens, F1 is the focal length of the first lens, and F2 is the focal length of the second lens.

[0014] Preferably, the first lens group contains a positive and negative lens combination that meets the following conditions:

[0015] D3<1mm

[0016] Vd4-Vd3>27

[0017] Wherein, D3 is the center distance of the positive and negative lens combination in the first lens group, Vd4 is the Abbe number of the negative lens in the positive and negative lens combination in the first lens group, and Vd3 is the Abbe number of the positive lens in the positive and negative lens combination in the first lens group.

[0018] Preferably, the focal length and position of the first lens group satisfy the following conditions:

[0019] 1.8mm<|FG1×si nθ|-TL1<9.1mm

[0020] Among them, FG1 is the focal length of the first lens group, θ is half of the maximum field angle of the camera lens optical system, and TL1 is the distance from the front vertex of the first lens to the variable aperture.

[0021] Preferably, the second lens group is a single negative lens curved toward the object plane, satisfying the following conditions:

[0022] -3.14 <F6 / f<-1.38

[0023] Among them, F6 is the focal length of the negative lens, and f is the focal length of the camera lens optical system.

[0024] Preferably, the first lens in the third lens group is a biconvex glass aspheric lens that meets the following conditions:

[0025] 0.68 <F7 / f<2.33

[0026] Among them, F7 is the focal length of the first lens in the third lens group, and f is the focal length of the camera lens optical system.

[0027] Preferably, the last lens in the third lens group is a biconvex glass spherical lens that meets the following conditions:

[0028] 0.63<(F7×F11) / [f×(F7+F11-d)]<0.75

[0029] Among them, F7 is the focal length of the first lens in the third lens group, F11 is the focal length of the last lens in the third lens group, d is the interval from the first lens to the last lens in the third lens group, and f is the focal length of the camera lens optical system.

[0030] Preferably, the last lens in the fourth lens group is a meniscus aspherical lens curved toward the object side, which satisfies the following conditions:

[0031] |F15|>300mm

[0032] T15≥3mm

[0033] Wherein, F15 is the focal length of the last lens in the fourth lens group, and T15 is the center thickness of the last lens in the fourth lens group.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] Effectively correcting aberrations, while achieving the maximum aperture of F1.4, superior performance can be achieved, with excellent imaging at infinity and close shooting distances, and effective calculation to eliminate some ghost images in the picture, with distortion less than 2%; by calculating and selecting a moving group that meets the low breathing effect, adjusting the light incident position and length of the moving group and the positive and negative optical power ratio, the picture angle changes when the system switches between long and short shooting tend to be smooth, greatly reducing the discomfort of video shooting and improving the photography experience; the structure is short and lightweight, and the moving group contains only one lens, which significantly reduces the weight and travel of the moving group, and the focusing efficiency is effectively guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the lens structure of a wide-angle, ultra-large aperture full-frame camera lens;

[0037] Figure 2 This is the spherical aberration curve of the wide-angle and ultra-large aperture full-frame camera lens;

[0038] Figure 3 This is a graph of the field curvature of a wide-angle, ultra-large aperture full-frame camera lens;

[0039] Figure 4 This is the distortion curve of a wide-angle, ultra-large aperture full-frame camera lens.

[0040] In the figure: 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; 15, the fifteenth lens. DETAILED DESCRIPTION

[0041] 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.

[0042] Example:

[0043] See also Figure 1 This embodiment provides a wide-angle ultra-large aperture full-frame camera lens, which includes a first lens group G1, a second lens group G2, a variable aperture, a third lens group G3 and a fourth lens group G4 in order from the object side to the imaging surface;

[0044] 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 and a fifth lens 5, wherein the fifth lens 5 is a glass aspherical lens;

[0045] The second lens group G2 is a focus group having negative optical power and includes a sixth lens 6. When focusing from infinity to near, the second lens group G2 is a focus compensation group (moving group) moving toward the object side.

[0046] The third lens group G3 is a fixed group having positive refractive power and includes a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10 and an eleventh lens 11;

[0047] The fourth lens group G4 includes a twelfth lens 12, a thirteenth lens 13, a fourteenth lens 14 and a fifteenth lens 15, wherein the number of lenses in the first lens group G1, the second lens group G2, the third lens group G3 and the fourth lens group G4 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.

[0048] In this embodiment, the first lens 1 and the second lens 2 are negative meniscus lenses curved toward the image plane, satisfying the following conditions:

[0049] D1>7mm

[0050] 1.31 <F2 / F1<2.52

[0051] Wherein, D1 is the center distance between the first lens 1 and the second lens 2 , F1 is the focal length of the first lens 1 , and F2 is the focal length of the second lens 2 .

[0052] In this embodiment, the first lens group G1 includes a positive and negative lens combination that meets the following conditions:

[0053] D3<1mm

[0054] Vd4-Vd3>27

[0055] Wherein, D3 is the center distance of the positive and negative lens combination in the first lens group G1, Vd4 is the Abbe number of the negative lens in the positive and negative lens combination in the first lens group G1, and Vd3 is the Abbe number of the positive lens in the positive and negative lens combination in the first lens group G1.

[0056] In this embodiment, the focal length and position of the first lens group G1 satisfy the following conditions:

[0057] 1.8mm<|FG1×si nθ|-TL1<9.1mm

[0058] Wherein, FG1 is the focal length of the first lens group G1, θ is half of the maximum field angle of the camera lens optical system, and TL1 is the distance from the front vertex of the first lens 1 to the variable aperture.

[0059] In this embodiment, the second lens group G2 is a single negative lens curved toward the object plane, satisfying the following conditions:

[0060] -3.14 <F6 / f<-1.38

[0061] Among them, F6 is the focal length of the negative lens, and f is the focal length of the camera lens optical system.

[0062] In this embodiment, the first lens (i.e., the seventh lens 7) in the third lens group G3 is a biconvex glass aspherical lens that meets the following conditions:

[0063] 0.68 <F7 / f<2.33

[0064] Wherein, F7 is the focal length of the first lens (the seventh lens 7) in the third lens group G3, and f is the focal length of the camera lens optical system.

[0065] In this embodiment, the last lens (i.e., the eleventh lens 11) in the third lens group G3 is a biconvex glass spherical lens that satisfies the following conditions:

[0066] 0.63<(F7×F11) / [f×(F7+F11-d)]<0.75

[0067] Among them, F7 is the focal length of the first lens (seventh lens 7) in the third lens group G3, F11 is the focal length of the last lens (eleventh lens 11) in the third lens group G3, d is the interval from the first lens (seventh lens 7) to the last lens (eleventh lens 11) in the third lens group G3, and f is the focal length of the camera lens optical system.

[0068] In this embodiment, the last lens in the fourth lens group G4 (i.e., the fifteenth lens 15) is a meniscus aspherical lens curved toward the object side, which satisfies the following conditions:

[0069] |F15|>300mm

[0070] T15≥3mm

[0071] Wherein, F15 is the focal length of the last lens (the fifteenth lens 15) in the fourth lens group G4, and T15 is the center thickness of the last lens (the fifteenth lens 15) in the fourth lens group G4.

[0072] 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:

[0073] Table 1

[0074]

[0075]

[0076] Table 2

[0077]

[0078]

[0079] 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:

[0080] Table 3

[0081] Conjugate distance Infinity Closest (0.3m) D1 6.74mm 2.74mm D2 2.72mm 6.72mm

[0082] As a preferred technical solution, the physical parameters of the camera lens in this embodiment are shown in Table 4 below:

[0083] Table 4

[0084] Focal length f 24.08mm Relative aperture FNO. 1.46 Field of viewω 83.9° Total optical length 123mm

[0085] 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.

[0086] In this embodiment, through the limitation of the above conditional formula, the aberration is effectively corrected, and while achieving the maximum aperture of F1.4, excellent performance can be obtained, the imaging is excellent at infinity and close shooting distances, and part of the ghost in the picture is effectively eliminated by calculation, and the distortion is less than 2%; the moving group that meets the low breathing effect is selected by calculation, and the light incident position and length and the positive and negative optical focal length ratio of the moving group are adjusted, so that the picture angle change of the system when switching between long and short shooting tends to be smooth, which greatly reduces the discomfort of video shooting and improves the photography experience; the structure is short and lightweight, and the moving group contains only one lens, which significantly reduces the weight and moving stroke of the moving group, and the focusing efficiency is effectively guaranteed.

[0087] 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 wide-angle, ultra-large aperture full-frame camera lens, characterized in that: From the object side to the imaging surface, it includes a first lens group (G1), a second lens group (G2), a variable aperture, a third lens group (G3) and a fourth lens group (G4); The first lens group (G1) is a fixed group having negative optical power and includes a first lens (1), a second lens (2), a third lens (3), a fourth lens (4) and a fifth lens (5); The second lens group (G2) serves as a focusing group and has negative optical power. When the sixth lens (6) is focused from infinity to near, the second lens group (G2) serves as a focus compensation group and moves toward the object side. The third lens group (G3) is a fixed group with positive refractive power, and includes a seventh lens (7), an eighth lens (8), a ninth lens (9), a tenth lens (10) and an eleventh lens (11); The fourth lens group (G4) includes a twelfth lens (12), a thirteenth lens (13), a fourteenth lens (14) and a fifteenth lens (15).

2. The wide-angle, ultra-large aperture, full-frame camera lens according to claim 1, characterized in that: The first lens (1) and the second lens (2) are negative meniscus lenses curved toward the image plane and meet the following conditions: D1>7mm 1.31 <F2 / F1<2.52 Wherein, D1 is the center distance between the first lens (1) and the second lens (2), F1 is the focal length of the first lens (1), and F2 is the focal length of the second lens (2).

3. The wide-angle, ultra-large aperture, full-frame camera lens according to claim 1, characterized in that: The first lens group (G1) contains a positive and negative lens combination that satisfies the following conditions: D3<1mm Vd4-Vd3>27 Wherein, D3 is the center distance of the positive and negative lens combination in the first lens group (G1), Vd4 is the Abbe number of the negative lens in the positive and negative lens combination in the first lens group (G1), and Vd3 is the Abbe number of the positive lens in the positive and negative lens combination in the first lens group (G1).

4. The wide-angle, ultra-large aperture, full-frame camera lens according to claim 1, characterized in that: The focal length and position of the first lens group (G1) satisfy the following conditions: 1.8mm<|FG1×sinθ|-TL1<9.1mm Wherein, FG1 is the focal length of the first lens group (G1), θ is half of the maximum field angle of the camera lens optical system, and TL1 is the distance from the front vertex of the first lens (1) to the variable aperture.

5. The wide-angle, ultra-large aperture, full-frame camera lens according to claim 1, characterized in that: The second lens group (G2) is a single negative lens bent toward the object plane, satisfying the following conditions: -3.14 <F6 / f<-1.38 Among them, F6 is the focal length of the negative lens, and f is the focal length of the camera lens optical system.

6. The wide-angle, ultra-large aperture, full-frame camera lens according to claim 1, characterized in that: The first lens in the third lens group (G3) is a biconvex glass aspheric lens that meets the following conditions: 0.68 <F7 / f<2.33 Among them, F7 is the focal length of the first lens in the third lens group (G3), and f is the focal length of the camera lens optical system.

7. The wide-angle, ultra-large aperture, full-frame camera lens according to claim 6, characterized in that: The last lens in the third lens group (G3) is a biconvex glass spherical lens that meets the following conditions: 0.63<(F7×F11) / [f×(F7+F11-d)]<0.75 Among them, F7 is the focal length of the first lens in the third lens group (G3), F11 is the focal length of the last lens in the third lens group (G3), d is the interval from the first lens to the last lens in the third lens group (G3), and f is the focal length of the camera lens optical system.

8. The wide-angle, ultra-large aperture, full-frame camera lens according to claim 1, characterized in that: The last lens in the fourth lens group (G4) is a meniscus aspherical lens curved toward the object side, which satisfies the following conditions: |F15|>300mm T15≥3mm Wherein, F15 is the focal length of the last lens in the fourth lens group (G4), and T15 is the center thickness of the last lens in the fourth lens group (G4).

Images