A 33mm focal length, wide aperture camera lens

Abstract

This invention provides a 33mm focal length large aperture camera lens, comprising, from object to image, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens. An aperture stop is provided between the seventh and eighth lenses. The third and fourth lenses form a first cemented lens group, the sixth and seventh lenses form a second cemented lens group, and the eighth and ninth lenses form a third cemented lens group. All lenses from the first to the twelfth are made of glass. The advantages of this invention are: a compact and lightweight structure, achieving high performance with a maximum aperture of F1.4 and distortion of less than 2% while maintaining cost and aesthetic advantages; the system is divided into three lens groups, simplifying the structure and reducing tolerance; and by calculating and selecting a moving lens group that satisfies low breath effect, discomfort during video shooting is greatly reduced, improving the photographic experience.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of camera lenses, in particular to a 33mm focal length large aperture camera lens. BACKGROUND

[0002] Due to the popularity of short videos on social platforms, more and more netizens share and exchange by shooting daily vlogs. For this group of people, it is more efficient to have a small and portable automatic mirrorless lens camera. Early mirrorless lenses on the market mainly focused on shooting quality, matching customer needs through large aperture, small distortion, and bokeh effect. However, the breathing shake generated during video shooting can make the viewer uncomfortable. Early products did not take this problem into account. If a lens with excellent resolution, small distortion, large aperture, portability, and other characteristics can greatly reduce breathing shake during video shooting, it will be favored by professionals in the market and have great product competitiveness. SUMMARY

[0003] The present application aims to solve the above-mentioned problems existing in the prior art mirrorless lens, and provides a 33mm focal length large aperture camera lens.

[0004] The present application is achieved by the following technical solutions: a 33mm focal length large aperture camera lens, sequentially including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens from the object side to the image side. A diaphragm is arranged between the seventh lens and the eighth lens. The third lens and the fourth lens form a first cemented lens group. The sixth lens and the seventh lens form a second cemented lens group. The eighth lens and the ninth lens form a third cemented lens group. The first lens to the twelfth lens are all made of glass.

[0005] Further, the first lens is a positive meniscus lens, the mirror surface of the first lens towards the object side is a first spherical surface, and the mirror surface of the first lens towards the image side is a second spherical surface. The curvature radii of the first spherical surface and the second spherical surface satisfy the following conditions:

[0006] R1 / R2<(0.34)^(R1 / |R1|)

[0007] Wherein, R1 is the curvature radius of the first spherical surface, and R2 is the curvature radius of the second spherical surface.

[0008] The Abbe number of the material of the first lens satisfies the following condition: VD1<32

[0009] Wherein, VD1 is the Abbe number of the material of the first lens.

[0010] Furthermore, the second lens is a spherical negative lens convex towards the object side, the object-side mirror surface of the second lens is a third convex spherical surface, the image-side mirror surface of the second lens is a fourth concave spherical surface, and the focal length of the second lens satisfies the following condition:

[0011] -1.28 <F2 / f<-2.55

[0012] Where F2 is the focal length of the second lens, and f is the focal length of the optical system.

[0013] Furthermore, the third lens is a concave spherical negative lens facing the object side, and the fourth lens is a convex spherical positive lens facing the object side. The focal length of the first cemented lens group composed of the third lens and the fourth lens satisfies the following condition:

[0014] |FU1 / f|>4.1

[0015] Wherein, FU1 is the focal length of the first cemented lens group;

[0016] The Abbe numbers of the materials of the third and fourth lenses satisfy the following condition:

[0017] twenty two <VD3<32

[0018] 45 <VD4<81.7

[0019] Among them, VD3 and VD4 are the Abbe numbers of the materials of the third lens and the fourth lens, respectively.

[0020] Furthermore, the fifth lens is a spherical positive lens convex to the object side, and the focal length of the fifth lens satisfies the following condition:

[0021] 0.86 <F5 / f<1.37

[0022] F5 is the focal length of the fifth lens.

[0023] Furthermore, the sixth lens is a convex spherical positive lens facing the object side, and the seventh lens is a concave spherical negative lens facing the image side. The sixth and seventh lenses form a second cemented lens group, and the refractive index and Abbe number of the material of the second cemented lens group satisfy the following conditions:

[0024] N6 <N7

[0025] VD6-VD7>20

[0026] Wherein, N6 and N7 are the refractive indices of the sixth and seventh lenses, respectively, and VD6 and VD7 are the Abbe numbers of the sixth and seventh lenses, respectively.

[0027] Furthermore, the eighth lens is a concave spherical negative lens facing the object side, and the ninth lens is a convex spherical positive lens facing the object side. The eighth and ninth lenses form a third cemented lens group, and the refractive index and Abbe number of the material of the third cemented lens group satisfy the following conditions:

[0028] N9 <N8

[0029] VD9-VD8>22

[0030] Wherein, N8 and N9 are the refractive indices of the eighth and ninth lenses, respectively, and VD8 and VD9 are the Abbe numbers of the eighth and ninth lenses, respectively.

[0031] The focal length of the third cemented lens group satisfies the following condition:

[0032] -4.2 <FU3 / f<-2.35

[0033] Wherein, FU3 is the focal length of the third cemented lens group.

[0034] Furthermore, the tenth lens is a spherical positive lens convex to the image side, and the focal length of the tenth lens satisfies the following condition:

[0035] 0.88 <F10 / f<1.37

[0036] F10 is the focal length of the tenth lens.

[0037] Furthermore, the eighth, ninth, and tenth lenses are motor-driven moving lens groups, and the focal lengths and moving distances of the eighth and tenth lenses satisfy the following relationship:

[0038] -195 <FM*F8 / F10*D<-105

[0039] Where FM is the focal length of the moving lens group, F8 is the focal length of the eighth lens, F10 is the focal length of the tenth lens, and D is the moving distance.

[0040] Furthermore, the eleventh lens is a convex spherical positive lens facing the object side, and the focal length of the eleventh lens satisfies the following condition:

[0041] 1.32 <F11 / f<2.4

[0042] Where F11 is the focal length of the eleventh lens;

[0043] The twelfth lens is a concave spherical negative lens facing the object side, and the focal length of the twelfth lens satisfies the following condition:

[0044] -3.3 <F12 / f<-1.8

[0045] F12 is the focal length of the twelfth lens.

[0046] The beneficial effects of this invention are as follows: each lens element is made of spherical glass, resulting in a compact and lightweight structure. While achieving cost and aesthetic advantages, it also delivers high performance with a maximum aperture of F1.4, providing excellent imaging at infinity and close-up distances with distortion less than 2%. The system is divided into three lens groups, simplifying the structure and reducing tolerance. By calculating and selecting a moving lens group that satisfies low breathing effect, and adjusting the incident light position and length of the moving lens group, as well as the ratio of positive and negative optical power, the angle of view changes during switching between near and far shooting become smoother, greatly reducing discomfort during video shooting and improving the photography experience. The smaller size and weight of the moving lens group reduce the motor load, effectively ensuring focusing efficiency. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the structure of the present invention;

[0048] Figure 2 This is the MTF diagram of the present invention;

[0049] Figure 3 This is the optical distortion diagram of the present invention;

[0050] Figure 4 This is the full-field MTF diagram of the present invention;

[0051] Figure 5 This is a relative illumination diagram of the present invention;

[0052] Reference numerals: G1, first lens; G2, second lens; G3, third lens; G4, fourth lens; G5, fifth lens; G6, sixth lens; G7, seventh lens; G8, eighth lens; G9, ninth lens; G10, tenth lens; G11, eleventh lens; G12, twelfth lens; U1, first cemented lens group; U2, second cemented lens group; U3, third cemented lens group. Detailed Implementation

[0053] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0054] like Figure 1As shown, a 33mm focal length large aperture camera lens, from the object side to the image side, includes a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, a fifth lens G5, a sixth lens G6, a seventh lens G7, an eighth lens G8, a ninth lens G9, a tenth lens G10, an eleventh lens G11, and a twelfth lens G12. An aperture stop is provided between the seventh lens G7 and the eighth lens G8. The third lens G3 and the fourth lens G4 form a first cemented lens group U1. The sixth lens G6 and the seventh lens G7 form a second cemented lens group U2. The eighth lens G8 and the ninth lens G9 form a third cemented lens group U3. The first lens G1 to the twelfth lens G12 are all made of glass.

[0055] Preferably, the first lens G1 is a meniscus positive lens, the object-side mirror surface of the first lens G1 is a first spherical surface, and the image-side mirror surface of the first lens G1 is a second spherical surface. The radii of curvature of the first and second spherical surfaces satisfy the following condition:

[0056] R1 / R2<(0.34)^(R1 / |R1|)

[0057] Where R1 is the radius of curvature of the first sphere and R2 is the radius of curvature of the second sphere;

[0058] The Abbe number of the material of the first lens G1 satisfies the following condition: VD1 < 32

[0059] Wherein, VD1 is the Abbe number of the material of the first lens G1.

[0060] Preferably, the second lens G2 is a spherical negative lens convex towards the object side, the object-side mirror surface of the second lens G2 is a third convex spherical surface, the image-side mirror surface of the second lens G2 is a fourth concave spherical surface, and the focal length of the second lens G2 satisfies the following condition:

[0061] -1.28 <F2 / f<-2.55

[0062] Where F2 is the focal length of the second lens G2, and f is the focal length of the optical system.

[0063] Preferably, the third lens G3 is a concave spherical negative lens facing the object side, and the fourth lens G4 is a convex spherical positive lens facing the object side. The focal length of the first cemented lens group U1 composed of the third lens G3 and the fourth lens G4 satisfies the following condition:

[0064] |FU1 / f|>4.1

[0065] Wherein, FU1 is the focal length of the first cemented lens group U1;

[0066] The Abbe numbers of the materials of the third lens G3 and the fourth lens G4 satisfy the following condition:

[0067] twenty two <VD3<32

[0068] 45 <VD4<81.7

[0069] Among them, VD3 and VD4 are the Abbe numbers of the materials of the third lens G3 and the fourth lens G4, respectively.

[0070] Preferably, the fifth lens G5 is a convex spherical positive lens facing the object side, and the focal length of the fifth lens G5 satisfies the following condition:

[0071] 0.86 <F5 / f<1.37

[0072] F5 is the focal length of the fifth lens G5.

[0073] Preferably, the sixth lens G6 is a convex spherical positive lens facing the object side, and the seventh lens G7 is a concave spherical negative lens facing the image side. The sixth lens G6 and the seventh lens G7 form the second cemented lens group U2, and the refractive index and Abbe number of the material of the second cemented lens group U2 satisfy the following conditions:

[0074] N6 <N7

[0075] VD6-VD7>20

[0076] Wherein, N6 and N7 are the refractive indices of the materials of the sixth lens G6 and the seventh lens G7, respectively, and VD6 and VD7 are the Abbe numbers of the materials of the sixth lens G6 and the seventh lens G7, respectively.

[0077] Preferably, the eighth lens G8 is a concave spherical negative lens facing the object side, and the ninth lens G9 is a convex spherical positive lens facing the object side. The eighth lens G8 and the ninth lens G9 form a third cemented lens group U3. The refractive index and Abbe number of the material of the third cemented lens group U3 satisfy the following conditions:

[0078] N9 <N8

[0079] VD9-VD8>22

[0080] Wherein, N8 and N9 are the refractive indices of the materials of the eighth lens G8 and the ninth lens G9, respectively, and VD8 and VD9 are the Abbe numbers of the materials of the eighth lens G8 and the ninth lens G9, respectively.

[0081] The focal length of the third cemented lens group U3 satisfies the following condition:

[0082] -4.2 <FU3 / f<-2.35

[0083] Wherein, FU3 is the focal length of the third cemented lens group U3.

[0084] Preferably, the tenth lens G10 is a spherical positive lens convex to the image side, and the focal length of the tenth lens G10 satisfies the following condition:

[0085] 0.88 <F10 / f<1.37

[0086] F10 is the focal length of the tenth lens G10.

[0087] Preferably, the eighth lens G8, the ninth lens G9, and the tenth lens G10 are a motor-driven moving lens group structure, and the focal length and moving distance of the eighth lens G8 and the tenth lens G10 satisfy the following relationship:

[0088] -195 <FM*F8 / F10*D<-105

[0089] Where FM is the focal length of the moving lens group, F8 is the focal length of the eighth lens G8, F10 is the focal length of the tenth lens G10, and D is the moving distance.

[0090] Preferably, the eleventh lens G11 is a spherical positive lens convex to the object side, and the focal length of the eleventh lens G11 satisfies the following condition:

[0091] 1.32 <F11 / f<2.4

[0092] Where F11 is the focal length of the eleventh lens G11;

[0093] The twelfth lens G12 is a concave spherical negative lens facing the object side, and the focal length of the twelfth lens G12 satisfies the following condition:

[0094] -3.3 <F12 / f<-1.8

[0095] F12 is the focal length of the twelfth lens G12.

[0096] As a preferred technical solution, the parameters of the lens embodiment are shown in the table below:

[0097] Lens No. Radius Lens Separation Lens Material Aperture Conic Constant First Lens 58.00 3.00 H-ZF3 34.4 0 300.00 0.80 AIR 33.8 0 Second Lens 270.00 2.20 H-ZPK5 32.9 0 26.00 8.00 AIR 28.7 0 Third Lens -50.00 3.00 H-ZF3 28.3 0 Fourth Lens 90.00 6.00 H-LAK11 28.8 0 -40.00 0.80 AIR 29.1 0 Fifth Lens 33.00 6.00 H-ZF50 28.1 0 -300.00 1.50 AIR 27.0 0 Sixth Lens 24.00 4.00 H-LAK11 23.1 0 Seventh Lens -100.00 1.50 H-ZF50 22.8 0 17.80 5.00 AIR 19.2 0 Stop INFINITY 10.59 18.5 0 Eighth Lens -17.00 1.50 H-ZF3 17.5 0 Ninth Lens 300.00 4.93 H-BAK8 20.2 0 -20.46 0.16 AIR 21.6 0 Tenth Lens 105.18 3.87 H-ZLAF68N 24.4 0 -54.73 1.18 AIR 24.9 0 Eleventh Lens 50.00 5.98 H-LAF54 25.9 0 -300.00 3.58 AIR 25.5 0 Twelfth Lens -49.75 1.50 H-ZLAF53B 24.9 0 500.00 13.00 AIR 25.2 0

[0098] The large-aperture camera lens provided by this invention has an effective focal length of f = 33mm and a relative aperture of F = 1.4. A schematic diagram of the lens structure is shown below. Figure 1 As shown.

[0099] Figure 2 The MTF curve of the lens of this invention for the 0-0.85 field of view shows that at a spatial frequency of 30, the MTF value of the 0-0.85 field of view is above 0.6, indicating that the lens has clear imaging and excellent performance.

[0100] Figure 3 The field curvature and distortion curves of the lens of this invention are shown. It can be seen that the meridional field curvature and sagittal field curvature are less than 0.1, and the maximum distortion is less than 1%, all of which meet the requirements of imaging performance.

[0101] Figure 4 The MTF curves of the lens of this invention are shown at spatial frequencies of 10 and 30 lp / mm within the 0-1.0 field of view. It can be seen that the MTF curve changes smoothly from the central field of view of 0-0.85, indicating stable lens performance.

[0102] Figure 5 The relative illumination curve of the lens of this invention shows that the relative illumination at the edge is greater than 30%, which will not cause vignetting during photography and meets the imaging performance requirements.

[0103] Based on the disclosure and teachings of the foregoing specification, those skilled in the art can make appropriate changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.

Claims

1. A 33mm focal length, large aperture camera lens, characterized in that: From object to image, the lens consists of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens. An aperture stop is provided between the seventh and eighth lenses. The third and fourth lenses form a first cemented lens group, the sixth and seventh lenses form a second cemented lens group, and the eighth and ninth lenses form a third cemented lens group. All lenses from the first to the twelfth are made of glass. The first lens is a meniscus positive lens, and the second lens... The first lens is a spherical negative lens convex to the object side; the second lens is a spherical negative lens concave to the object side; the third lens is a spherical positive lens convex to the object side; the fourth lens is a spherical positive lens convex to the object side; the fifth lens is a spherical positive lens convex to the object side; the sixth lens is a spherical positive lens convex to the object side; the seventh lens is a spherical negative lens concave to the image side; the eighth lens is a spherical negative lens concave to the object side; the ninth lens is a spherical positive lens convex to the object side; the tenth lens is a spherical positive lens convex to the image side; the eleventh lens is a spherical positive lens convex to the object side; and the twelfth lens is a spherical negative lens concave to the object side. The eighth, ninth, and tenth lenses form a motor-driven moving lens group structure. The focal length and moving distance of the eighth and tenth lenses satisfy the following relationship: -195 <FM*F8 / F10*D<-105 Where FM is the focal length of the moving lens group, F8 is the focal length of the eighth lens, F10 is the focal length of the tenth lens, and D is the moving distance.

2. The 33mm focal length large aperture camera lens according to claim 1, characterized in that: The object-side mirror of the first lens is a first spherical surface, and the image-side mirror of the first lens is a second spherical surface. The radii of curvature of the first and second spherical surfaces satisfy the following condition: R1 / R2<(0.34)^(R1 / |R1|) Where R1 is the radius of curvature of the first sphere and R2 is the radius of curvature of the second sphere; The Abbe number of the material of the first lens satisfies the following condition: VD1 < 32 Wherein, VD1 is the Abbe number of the material of the first lens.

3. A 33mm focal length large aperture camera lens according to claim 1, characterized in that: The object-facing surface of the second lens is a third convex spherical surface, and the image-facing surface of the second lens is a fourth concave spherical surface. The focal length of the second lens satisfies the following condition: -1.28 <F2 / f<-2.55 Where F2 is the focal length of the second lens, and f is the focal length of the optical system.

4. A 33mm focal length large aperture camera lens according to claim 3, characterized in that: The focal length of the first cemented lens group composed of the third and fourth lenses satisfies the following condition: |FU1 / f|>4.1 Wherein, FU1 is the focal length of the first cemented lens group; The Abbe numbers of the materials of the third and fourth lenses satisfy the following condition: twenty two <VD3<32 45 <VD4<81.7 Among them, VD3 and VD4 are the Abbe numbers of the materials of the third lens and the fourth lens, respectively.

5. A 33mm focal length large aperture camera lens according to claim 3, characterized in that: The focal length of the fifth lens satisfies the following condition: 0.86 <F5 / f<1.37 F5 is the focal length of the fifth lens.

6. A 33mm focal length large aperture camera lens according to claim 1, characterized in that: The sixth and seventh lenses form a second cemented lens group, and the refractive index and Abbe number of the material of the second cemented lens group satisfy the following conditions: N6 <N7 VD6-VD7>20 Wherein, N6 and N7 are the refractive indices of the sixth and seventh lenses, respectively, and VD6 and VD7 are the Abbe numbers of the sixth and seventh lenses, respectively.

7. A 33mm focal length large aperture camera lens according to claim 3, characterized in that: The eighth and ninth lenses together form a third cemented lens group, and the refractive index and Abbe number of the material of the third cemented lens group satisfy the following conditions: N9 <N8 VD9-VD8>22 Wherein, N8 and N9 are the refractive indices of the eighth and ninth lenses, respectively, and VD8 and VD9 are the Abbe numbers of the eighth and ninth lenses, respectively. The focal length of the third cemented lens group satisfies the following condition: -4.2 <FU3 / f<-2.35 Wherein, FU3 is the focal length of the third cemented lens group.

8. A 33mm focal length large aperture camera lens according to claim 3, characterized in that: The focal length of the tenth lens satisfies the following condition: 0.88 <F10 / f<1.37 F10 is the focal length of the tenth lens.

9. A 33mm focal length large aperture camera lens according to claim 3, characterized in that: The focal length of the eleventh lens satisfies the following condition: 1.32 <F11 / f<2.4 Where F11 is the focal length of the eleventh lens; The focal length of the twelfth lens satisfies the following condition: -3.3 <F12 / f<-1.8 F12 is the focal length of the twelfth lens.

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