24mm breathing-eliminating full-frame camera lens

Abstract

The invention discloses a 24-mm breathing-eliminating full-frame camera lens. The 24-mm breathing-eliminating 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, the focal power is positive, the first lens group 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, and the first lens is a meniscus negative lens bent towards an image surface; the second lens group serves as a focusing group, the focal power is positive, the second lens group comprises a ninth lens and a tenth lens, and the ninth lens is an aspheric glass lens; according to the invention, the high performance of the F1.8 maximum aperture can be realized, the imaging is excellent at infinity and close-up distance, the distortion is less than 3%, the structure is simplified, and the tolerance tolerance is reduced, so that the change of the drawing angle of the system tends to be gentle during the switching of far and near shooting, the discomfort of video shooting is greatly reduced, and the shooting experience is improved.

Description

Technical Field

[0001] The invention relates to the technical field of camera lenses, in particular to a 24mm breath-free full-frame camera lens. Background Art

[0002] Due to the popularity of short videos on social platforms, more and more netizens share and communicate by shooting daily vlogs. For these people, having a small and lightweight automatic micro-single camera lens can achieve twice the result with half the effort. In the early days, the micro-single lenses on the market mainly focused on the quality of taking pictures, and matched the needs of customers through large apertures, small distortions, blur effects, etc. However, many early products did not take into account the uncomfortable breathing jitters that occurred during video shooting. If a lens that can greatly reduce breathing jitters when shooting videos in addition to excellent resolution, small distortion, large aperture, light and compact can be developed, it will definitely be favored by professionals in the market and have great product competitiveness. Therefore, the present invention designs a 24mm full-frame camera lens with anti-breathing 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 24mm anti-breathing full-frame camera lens, which can achieve high performance at a maximum aperture of F1.8, excellent imaging at infinity and close shooting distances, distortion less than 3%, simplify the structure, and reduce the tolerance tolerance, so that 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.

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

[0005] A 24mm breath-free full-frame camera lens, comprising a first lens group, a variable aperture, a second lens group and a third lens group in sequence 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 is a focusing group with positive optical power, and includes a ninth lens and a tenth lens, wherein the ninth lens is an aspherical glass lens;

[0008] The third lens group is a fixed group with negative optical power, and includes an eleventh lens, a twelfth lens and a thirteenth lens.

[0009] Preferably, the first lens 1 is a negative meniscus lens curved toward the image plane, satisfying the following conditions:

[0010] -4<(L1 R2+L1 R1) / (L1 R2-L1 R1)<-1.5

[0011] Wherein, L1 R1 is the curvature radius of a side surface of the first lens 1 close to the object side, and L1 R2 is the curvature radius of a side surface of the first lens 1 close to the imaging surface.

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

[0013] Nd3>1.77

[0014] 4.4 <F3 / f<7.1

[0015] Wherein, Nd3 is the refractive index of the third lens, F3 is the focal length of the third lens, and f is the focal length of the camera lens optical system.

[0016] Preferably, at least two lenses in the first lens group satisfy the following conditions:

[0017] Vd>70

[0018] Wherein, Vd is the Abbe number of the lens material in the first lens group.

[0019] Preferably, the focal length of the first lens group satisfies the following conditions:

[0020] 0.59 <FG1 / f<2.43

[0021] Among them, FG1 is the focal length of the first lens group, and f is the focal length of the camera lens optical system.

[0022] Preferably, the first lens in the second lens group is an aspherical negative meniscus lens curved toward the object plane, satisfying the following conditions:

[0023] |L9R1| / f<0.7

[0024] Wherein, L9R1 is the curvature radius of the side surface of the ninth lens close to the object side, and f is the focal length of the camera lens optical system.

[0025] Preferably, the focal length of the second lens group satisfies the following conditions:

[0026] 1.21 <FG2 / f<2.79

[0027] Wherein, FG2 is the focal length of the second lens group, and f is the focal length of the camera lens optical system. Preferably, at least one lens in the third lens group satisfies the following conditions:

[0028] Vd>70.4

[0029] Wherein, Vd is the Abbe number of the lens material in the third lens group.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The invention has a short and lightweight structure, and achieves high performance of a maximum aperture of F1.8 while achieving cost and appearance advantages. It has excellent imaging at infinity and close shooting distances, and distortion is less than 3%. The system is divided into three lens groups to simplify the structure and reduce tolerance. Low-wavelength-height-transmittance glass materials are used to restore true colors. A moving group that meets the low breathing effect is selected by calculation, and the light incident position and length of the moving group and the positive and negative optical power ratio are adjusted, so that the picture angle changes of the system when switching between long and short shooting tend to be smooth, which greatly reduces the discomfort of video shooting and improves the photography experience. Aspherical glass lenses are used in the moving group to significantly reduce the size and weight of the moving group, the motor load is small, and the focusing efficiency is effectively guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the lens structure of a 24mm full-frame camera lens with no breathing;

[0033] Figure 2 This is the spherical aberration curve of the 24mm de-breathing full-frame camera lens;

[0034] Figure 3 This is the field curvature curve of a 24mm de-breathing full-frame camera lens;

[0035] Figure 4 This is the distortion curve of a 24mm full-frame camera lens with zero breathing.

[0036] 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. DETAILED DESCRIPTION

[0037] 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.

[0038] Example:

[0039] See also Figure 1, this embodiment provides a 24mm breath-free 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;

[0040] The first lens group G1 is a fixed group with positive 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;

[0041] The second lens group G2 is a focusing group (moving group) with positive optical power, and includes a ninth lens 9 and a tenth lens 10, wherein the ninth lens 9 is an aspherical glass lens;

[0042] The third lens group G3 is a fixed group with negative optical power, and includes an eleventh lens 11, a twelfth lens 12 and a thirteenth lens 13. 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.

[0043] In this embodiment, the first lens 1 is a negative meniscus lens curved toward the image plane, satisfying the following conditions:

[0044] -4<(L1 R2+L1 R1) / (L1 R2-L1 R1)<-1.5

[0045] Wherein, L1 R1 is the curvature radius of a side surface of the first lens 1 close to the object side, and L1 R2 is the curvature radius of a side surface of the first lens 1 close to the imaging surface.

[0046] In this embodiment, the third lens 3 is a positive meniscus lens curved toward the image plane, satisfying the following conditions:

[0047] Nd3>1.77

[0048] 4.4 <F3 / f<7.1

[0049] Wherein, Nd3 is the refractive index of the third lens 3, F3 is the focal length of the third lens 3, and f is the focal length of the camera lens optical system.

[0050] In this embodiment, at least two lenses in the first lens group G1 satisfy the following conditions:

[0051] Vd>70

[0052] Wherein, Vd is the Abbe number of the lens material in the first lens group G1.

[0053] In this embodiment, the focal length of the first lens group G1 satisfies the following conditions:

[0054] 0.59 <FG1 / f<2.43

[0055] Wherein, FG1 is the focal length of the first lens group G1, and f is the focal length of the camera lens optical system.

[0056] In this embodiment, the first lens (i.e., the ninth lens 9) in the second lens group G2 is an aspherical negative meniscus lens curved toward the object plane, satisfying the following conditions:

[0057] |L9R1| / f<0.7

[0058] Wherein, L9R1 is the curvature radius of the side surface of the first lens (ninth lens 9) in the second lens group G2 close to the object side, and f is the focal length of the camera lens optical system.

[0059] In this embodiment, the focal length of the second lens group G2 satisfies the following conditions:

[0060] 1.21 <FG2 / f<2.79

[0061] Wherein, FG2 is the focal length of the second lens group G2, and f is the focal length of the camera lens optical system. In this embodiment, at least one lens in the third lens group G3 satisfies the following conditions:

[0062] Vd>70.4

[0063] Wherein, Vd is the Abbe number of the lens material in the third lens group G3.

[0064] 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:

[0065] Table 1

[0066]

[0067]

[0068] Table 2

[0069]

[0070]

[0071] 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:

[0072] Table 3

[0073] Conjugate distance Infinity Closest (0.2m) D1 15.7mm 11.25mm D2 0.9mm 5.35mm

[0074] As a preferred technical solution, the physical parameters of the camera lens in this embodiment are shown in Table 4 below:

[0075] Table 4

[0076] Focal length f 24.34mm Relative aperture FNO. 1.85 Field of viewω 84.1° Total optical length 112.7mm

[0077] 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.

[0078] In this embodiment, through the limitation of the above conditional formula, the structure is short and lightweight, and while achieving cost and appearance advantages, the high performance of the maximum aperture of F1.8 is achieved, the imaging is excellent at infinity and close shooting distances, and the distortion is less than 3%; the system is divided into 3 groups of lens groups to simplify the structure and reduce the tolerance tolerance; low wave height transmittance glass materials are used to restore the true color; 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; aspherical glass lenses are used in the moving group to significantly reduce the size and weight of the moving group, the motor load is small, and the focusing efficiency is effectively guaranteed.

[0079] 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 24mm breath-free 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 optical power, and includes 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) is a focusing group with positive optical power, and comprises a ninth lens (9) and a tenth lens (10), wherein the ninth lens (9) is an aspherical glass lens; The third lens group (G3) is a fixed group with negative optical power, and includes an eleventh lens (11), a twelfth lens (12) and a thirteenth lens (13); The first lens (1) is a negative meniscus lens curved toward the image plane and meets the following conditions: -4<(L1R2+L1R1) / (L1R2-L1R1)<-1.5 Wherein, L1R1 is the curvature radius of a side surface of the first lens (1) close to the object side, and L1R2 is the curvature radius of a side surface of the first lens (1) close to the imaging surface.

2. A 24mm breath-free full-frame camera lens according to claim 1, characterized in that: The third lens (3) is a positive meniscus lens curved toward the image plane and meets the following conditions: Nd3>1.77 4.4 <F3 / f<7.1 Wherein, Nd3 is the refractive index of the third lens (3), F3 is the focal length of the third lens (3), and f is the focal length of the camera lens optical system.

3. A 24mm breath-free full-frame camera lens according to claim 1, characterized in that: At least two lenses in the first lens group (G1) satisfy the following conditions: Vd>70 Wherein, Vd is the Abbe number of the lens material in the first lens group (G1).

4. The 24mm anti-breathing full-frame camera lens according to claim 1, characterized in that: The focal length of the first lens group (G1) satisfies the following conditions: 0.59 <FG1 / f<2.43 Among them, FG1 is the focal length of the first lens group (G1), and f is the focal length of the camera lens optical system.

5. The 24mm anti-breathing full-frame camera lens according to claim 1, characterized in that: The first lens in the second lens group (G2) is an aspherical negative meniscus lens curved toward the object plane, and satisfies the following conditions: |L9R1| / f<0.7 Wherein, L9R1 is the curvature radius of the side surface of the first lens in the second lens group (G2) close to the object side, and f is the focal length of the camera lens optical system.

6. The 24mm anti-breathing full-frame camera lens according to claim 1, characterized in that: The focal length of the second lens group (G2) satisfies the following conditions: 1.21 <FG2 / f<2.79 Among them, FG2 is the focal length of the second lens group (G2), and f is the focal length of the camera lens optical system.

7. The 24mm anti-breathing full-frame camera lens according to claim 1, characterized in that: At least one lens in the third lens group (G3) satisfies the following conditions: Vd>70.4 Wherein, Vd is the Abbe number of the lens material in the third lens group (G3).

Images