Internal focusing photography non-reflective lens
By designing an internal focusing mirrorless lens, the problem of the lack of wide-angle focal length and high cost in APS-C mirrorless cameras has been solved, achieving lens miniaturization and weight reduction to meet diverse shooting needs.
Patent Information
- Application Number
- CN202511694470.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-18
- Publication Date
- 2025-12-19
AI Technical Summary
Existing APS-C mirrorless cameras lack wide-angle lenses, and some lenses are expensive, making it difficult to meet diverse shooting needs and resulting in high costs.
Design an internal focusing mirrorless camera lens, comprising a negative optical power first lens group, a positive optical power second lens group, an aperture, a positive optical power third lens group, and a fourth lens group arranged sequentially along the optical axis. The third lens group is the focusing group. The lens groups are rationally distributed to achieve a large aperture, wide-angle field of view, and small size and lightweight design.
It fills the gap in wide-angle focal length, reduces lens costs, and at the same time achieves lens miniaturization and weight reduction, improving the portability and image quality of imaging devices.
Smart Images
Figure CN121165299A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of photographic lenses, in particular to an inner focusing photographic mirrorless lens. BACKGROUND
[0002] Mirrorless camera is a kind of interchangeable lens digital camera without a mirror, compared with the traditional DSLR, it cancels the optical viewfinder and mirror structure, and directly displays the picture captured by the sensor through the electronic viewfinder (EVF) or screen. Mirrorless camera is favored by photography enthusiasts and professional users for its lightness, high performance and gradually mature lens group.
[0003] In recent years, in the photography market, thanks to the high performance and portability of mirrorless cameras, the user group is increasing, and there are diverse needs for various shooting scenes.
[0004] There is still a gap in the focal length range of the original factory matching lens that can be used on the half-frame mirrorless, especially the wide-angle focal length, and the price of the lens of some focal lengths is expensive, which is not acceptable to all photography consumers. SUMMARY
[0005] In order to overcome the shortcomings of the prior art that there is still a gap in the focal length range of the original factory matching lens that can be used on the half-frame mirrorless, especially the wide-angle focal length, and the price of the lens of some focal lengths is expensive, which is not acceptable to all photography consumers, the present application provides an inner focusing photographic mirrorless lens, which comprises a first lens group with negative optical power, a second lens group with positive optical power, a diaphragm, a third lens group with positive optical power, and a fourth lens group with positive optical power arranged in order along the optical axis from the object side to the image side; the third lens group is a focusing group, and the first lens group satisfies: -2.1≤F1 / F≤-1.9, wherein F1 represents the synthetic focal length of the first lens group, and F represents the focal length of the entire optical imaging system.
[0006] Optionally, the first lens group comprises a first lens with negative optical power, a second lens with negative optical power, a third lens with negative optical power, a fourth lens with positive optical power, and a fifth lens with negative optical power.
[0007] Optionally, the second lens group comprises a sixth lens with positive optical power and a seventh lens with negative optical power, and the second lens group satisfies: -1.0≤F2 / F≤-0.7, wherein F2 represents the synthetic focal length of the second lens group, and F represents the focal length of the optical imaging system.
[0008] Optionally, the third lens group has an eighth lens with negative optical power, a ninth lens with positive optical power, and a tenth lens with negative optical power.
[0009] Optionally, the fourth lens group comprises a eleventh lens with positive refractive power, a twelfth lens with positive refractive power, a thirteenth lens with positive refractive power, and a fourteenth lens with negative refractive power.
[0010] Optionally, the tenth lens in the third lens group moves along the optical axis, and the eighth lens and the ninth lens are stationary on the image side.
[0011] Optionally, the third lens, the fourth lens, and the fifth lens form a trilens group.
[0012] Optionally, the thirteenth lens and the fourteenth lens form a cemented lens group.
[0013] Optionally, the first lens has an Abbe number VDL1 and a refractive index NDL1, and satisfies the relationship: 25≤VDL1≤30, 1.7≤NDL1≤1.75.
[0014] Optionally, the second lens has an Abbe number VDL2 and a refractive index NDL2, and satisfies the relationship: 50≤VDL2≤55, 1.7≤NDL2≤1.75.
[0015] The first lens group has a suitable negative refractive power to ensure that the lens has a large-aperture wide-angle field of view, fills the gap in the wide-angle focal length of the original lens in the existing market, and has a small overall size and weight, thereby reducing the cost. The first lens group satisfies the condition: -2.1≤F1 / F≤-1.9, has a reasonable field of view and a rear working distance, and the light beam has a reasonable incidence height in the rear group. BRIEF DESCRIPTION OF DRAWINGS
[0016] The application will be further described below with reference to the accompanying drawings and examples.
[0017] Figure 1 is a lens configuration schematic diagram in some embodiments; Figure 2 is a lens configuration and optical path schematic diagram in some embodiments; Figure 3 is a spherical aberration schematic diagram when focusing at infinity in some embodiments; Figure 4 is a field curvature schematic diagram when focusing at infinity in some embodiments; Figure 5 is a distortion schematic diagram when focusing at infinity in some embodiments; Figure 6 is a magnification chromatic aberration schematic diagram when focusing at infinity in some embodiments Figure 7 is a spherical aberration schematic diagram when focusing at 1.5m in some embodiments; Figure 8is a schematic of field curvature at 1.5m focus for some embodiments; Figure 9 is a schematic of distortion at 1.5m focus for some embodiments; Figure 10 is a schematic of lateral chromatic aberration at 1.5m focus for some embodiments.
[0018] L1, first lens; L2, second lens; L3, third lens; L4, fourth lens; L5, fifth lens; L6, sixth lens; L7, seventh lens; L8, eighth lens; L9, ninth lens; L10, tenth lens; L11, eleventh lens; L12, twelfth lens; L13, thirteenth lens; L14, fourteenth lens; G1, first lens group; G2, second lens group; G3, third lens group; G4, fourth lens group; DETAILED DESCRIPTION The concept, specific structure and generated technical effects of the present application will be described clearly and completely in combination with embodiments and drawings, so as to fully understand the purpose, features and effects of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments, and other embodiments obtained by those skilled in the art on the basis of the embodiments of the present application without creative labor are within the scope of protection of the present application. In addition, all the coupling / connection relationships involved in the patent do not mean that the components are directly connected, but that a better coupling structure can be composed by adding or reducing coupling accessories according to the specific implementation. The technical features in the present application can be combined interactively without conflict.
[0019] The present application provides an internal focusing photographic mirrorless lens, which is used as an optical imaging key component in a micro single camera, comprising a first lens group G1 with negative focal power, a second lens group G2 with positive focal power, a diaphragm, a third lens group G3 with positive focal power, and a fourth lens group G4 with positive focal power arranged in order along the optical axis from the object side to the image side; the third lens group G3 is a focusing group, and the first lens group G1 satisfies the condition formula: -2.1≤F1 / F≤-1.9, wherein F1 represents the synthetic focal length of the first lens group G1, and F represents the focal length of the entire optical imaging system.
[0020] The first lens group has appropriate negative focal power to ensure that the lens has a large-aperture wide-angle field of view, fills the gap of the wide-angle focal length of the original factory matching lens in the existing market, and at the same time, the overall small size and light weight of the lens reduce the cost. Specifically, the first lens group G1 satisfies the condition formula: -2.1≤F1 / F≤-1.9, the first lens group G1 has a reasonable field of view angle and a rear working distance, and the beam incidence height at the rear group is in a reasonable interval.
[0021] If the condition satisfied by the first lens group G1 is lower than its lower limit, the optical power of the first lens group G1 decreases, and the divergence angle of the front group decreases. Although this reduces the burden on the relative aperture of the front and rear groups, it increases the overall length of the lens. If the condition satisfied by the first lens group G1 is higher than its upper limit, the optical power of the first lens group G1 increases, the divergence angle of the front group further increases, and the deflection angle of the rear group increases, thus increasing the burden on the relative aperture of the front and rear groups. Therefore, satisfying the above condition is the most reasonable.
[0022] In some embodiments, the first lens group G1 includes a first lens L1 with negative optical power, a second lens L2 with negative optical power, a third lens L3 with negative optical power, a fourth lens L4 with positive optical power, and a fifth lens with negative optical power. L5, the fifth lens with negative optical power.
[0023] Specifically, the first lens L1 is a concave-convex lens, the second lens L2 is a concave-convex lens, the third lens L3 is a concave lens, the fourth lens L4 is a convex lens, and the fifth lens... L5 is a concave-convex lens, the third lens L3, the fourth lens L4, and the fifth lens L5 forms a triple-cemented lens group. The first lens L1 has an Abbe number of VDL1 and a refractive index of NDL1, satisfying the following relationships: 25≤VDL1≤30 and 1.7≤NDL1≤1.75. The cemented lens group integrates three optical functions into one lens group, reducing the number of independent lenses in the lens, thereby reducing the size and weight of the lens.
[0024] In some embodiments, the second lens group G2 includes a sixth lens L6 with positive optical power and a seventh lens L7 with negative optical power. The second lens group G2 satisfies: -1.0≤F2 / F≤-0.7, where F2 represents the combined focal length of the second lens group G2, F represents the focal length of the optical imaging system, the Abbe number of the second lens L2 is VDL2, and the refractive index is NDL2, satisfying the relationships: 50≤VDL2≤55 and 1.7≤NDL2≤1.75.
[0025] Specifically, the sixth lens L6 is a concave-convex lens, the seventh lens L7 is a concave-convex lens, and the second lens group G2 satisfies: -1.0≤F2 / F≤-0.7, wherein F represents the focal length of the optical imaging system, and F2 represents the combined focal length of the second lens group G2. Satisfying -1.0≤F2 / F≤-0.7, the second lens group G2 can effectively correct the off-axis astigmatism and coma, while reducing the effective aperture of the light incident on the third lens group G3, reducing the lens aperture of the third lens group G3, and achieving the purpose of reducing the weight of the lens; if the expression satisfied by the second lens group G2 is lower than the lower limit value, the decrease in the optical power of the second lens group G2 causes the radii of curvature of the negative lens S1 surface and the S2 surface of the second lens group G2 to approach concentric circles, which is not conducive to processing and manufacturing. If the expression satisfied by the second lens group G2 is higher than the lower limit value, the increase in the optical power of the second lens group G2 causes the edge light incidence angle to increase, and the distortion and astigmatism cannot be well corrected, so the second lens group G2 satisfies: -1.0≤F2 / F≤-0.7, which is the most appropriate.
[0026] In some embodiments, the third lens group G3 has an eighth lens L8 with negative optical power, a ninth lens L9 with positive optical power, and a tenth lens L10 with negative optical power.
[0027] Specifically, the eighth lens L8 is a concave-convex lens, the ninth lens L9 is a convex lens, and the tenth lens L10 is a concave lens. Further, the tenth lens L10 in the third lens group G3 moves along the optical axis, and the eighth lens L8 and the ninth lens L9 are stationary on the image side. The third lens group G3 is a focusing assembly in the optical imaging system, and in the third lens group G3, only the tenth lens L10 can be moved to achieve focusing. By using a concave tenth lens L10, the focusing movement distance can be reduced, which is conducive to reducing the length of the system, reducing the weight of the focusing group and the load of the driving motor, and facilitating fast focusing of the imaging lens and imaging equipment.
[0028] In some embodiments, the fourth lens group G4 includes an eleventh lens L11 with positive optical power, a twelfth lens L12 with positive optical power, a thirteenth lens L13 with positive optical power, and a fourteenth lens L14 with negative optical power.
[0029] Specifically, the eleventh lens L11 is a concave-convex lens, the twelfth lens L12 is a concave-convex lens, the thirteenth lens L13 is a convex lens, and the fourteenth lens L14 is a concave-convex lens. The thirteenth lens L13 and the fourteenth lens L14 are combined into a cemented lens group.
[0030] Further, the third lens and the thirteenth lens are low-dispersion lenses, and the fifth lens and the tenth lens are special-dispersion lenses, which can reduce the purple edge or dispersion produced by the edge of the subject as much as possible when the internal focusing camera lens is used to shoot contrast pictures.
[0031] Specifically, the third lens and the thirteenth lens are low dispersion lenses with an Abbe number higher than 80 for light with a wavelength of 587.6 nm, and the fifth lens and the tenth lens are special dispersion lenses, which are different from normal dispersion lenses in that the normal dispersion lenses show an increase in refractive index with a decrease in wavelength, while the special dispersion lenses show an increase in refractive index with an increase in wavelength, facilitating dispersion correction of the visible spectrum.
[0032] Table 1 below lists the relevant parameters of each lens of the present embodiment, including surface type, radius of curvature, thickness, refractive index of the material, and Abbe number:
[0033] Table 2 below lists the conjugate data of the present embodiment, including object distance, focal length, thickness of lens surface 16 in Table 1, and thickness of lens surface 18 in Table 1:
[0034] The above is a specific description of the preferred embodiment of the present application, but the present application is not limited to the described embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present application, and these equivalent modifications or substitutions are all included within the scope defined by the claims of the present application.
Claims
1. An internal focusing photographic mirrorless lens characterized by comprising: The optical imaging system comprises, in order from the object side to the image side along the optical axis, a first lens group having negative refractive power, a second lens group having positive refractive power, a diaphragm, a third lens group having positive refractive power, and a fourth lens group having positive refractive power; the third lens group is a focusing group, and the first lens group satisfies -2.1≤F1 / F≤-1.9, wherein F1 represents the composite focal length of the first lens group, and F represents the focal length of the entire optical imaging system.
2. The internal focus photographic mirrorless lens of claim 1, wherein, The first lens group comprises a first lens having negative refractive power, a second lens having negative refractive power, a third lens having negative refractive power, a fourth lens having positive refractive power, and a fifth lens having negative refractive power.
3. The internal focus photographic mirrorless lens of claim 1, wherein, The second lens group comprises a sixth lens having positive refractive power and a seventh lens having negative refractive power, and the second lens group satisfies -1.0≤F2 / F≤-0.7, wherein F2 represents the composite focal length of the second lens group, and F represents the focal length of the optical imaging system.
4. The internal focus photographic mirrorless lens of claim 1, wherein, The third lens group comprises an eighth lens having negative refractive power, a ninth lens having positive refractive power, and a tenth lens having negative refractive power.
5. The internal focus photographic mirrorless lens of claim 1, wherein, The fourth lens group comprises an eleventh lens having positive refractive power, a twelfth lens having positive refractive power, a thirteenth lens having positive refractive power, and a fourteenth lens having negative refractive power.
6. The internal focus photographic mirrorless lens of claim 4, wherein, The tenth lens in the third lens group moves along the optical axis, and the eighth lens and the ninth lens are stationary relative to the image side.
7. The internal focus photographic mirrorless lens of claim 2, wherein, The third lens, the fourth lens, and the fifth lens form a triple cemented lens group.
8. The internal focus photographic mirrorless lens of claim 5, wherein, The thirteenth lens and the fourteenth lens form a cemented lens group.
9. The internal focus photographic mirrorless lens of claim 2, wherein, The first lens has an Abbe number VDL1 and a refractive index NDL1, and satisfies the relationship 25≤VDL1≤30 and 1.7≤NDL1≤1.
75.
10. The internal focus photographic mirrorless lens of claim 2, wherein, The second lens has an Abbe number VDL2 and a refractive index NDL2, and satisfies the relationship 50≤VDL2≤55 and 1.7≤NDL2≤1.75.