Wide-angle movie lens

Abstract

The invention provides a wide-angle film lens. A first lens is a convex-concave lens with negative focal power; the second lens is a convex-concave lens with positive focal power, and the third lens is a convex-concave lens with negative focal power; the fourth lens is a convex-concave lens with negative focal power or a concave-concave lens with negative focal power; the fifth lens is a concave-convex lens with positive focal power; the sixth lens is a concave-concave lens with negative focal power; the seventh lens is a convex-convex lens with positive focal power; the eighth lens is a concave-convex lens with negative focal power; the ninth lens is a convex-convex lens with positive focal power; the tenth lens is a concave-concave lens with negative focal power; the eleventh lens is a convex-convex lens with positive focal power; the twelfth lens is a concave-concave lens with negative focal power; the thirteenth lens is a convex-convex lens with positive focal power; and the fourteenth lens is a convex-convex lens with positive focal power. The embodiment of the invention aims to realize a wide-angle, low-distortion and low-breathing-effect high-resolution movie lens.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical lens, and particularly to a wide-angle movie lens. BACKGROUND

[0002] In recent years, the movie lens has become one of the mainstream ways of movie shooting due to its excellent balance of imaging quality and high-resolution shooting capability. The wide-angle lens is crucial in movie narration, and the distortion of the current wide-angle movie lens is obvious, and the post-correction will also lose the picture quality and the visual angle; when the focal point shifts at different object distances, the visual coherence is not strong, and the breathing effect has a very high requirement; when the object distance is switched, the close-up resolution is not considered, and the imaging quality is unstable when the object distance changes. SUMMARY

[0003] The embodiment of the present application provides a wide-angle movie lens to realize a high-resolution movie lens with wide angle, low distortion and low breathing effect.

[0004] The embodiment of the present application provides a wide-angle movie lens, which comprises a first lens group with positive focal length, an aperture and a second lens group with positive focal length arranged in sequence along the optical axis from the object side to the image side, the first lens group is a fixed group, and the second lens group is a focusing group.

[0005] The first lens group comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in sequence along the optical axis from the object side to the image side; and the second lens group comprises an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens and a fourteenth lens arranged in sequence along the optical axis from the object side to the image side.

[0006] The first lens is a convex-concave lens with negative focal length; the second lens is a convex-concave lens with positive focal length, the third lens is a convex-concave lens with negative focal length; the fourth lens is a convex-concave lens with negative focal length or a concave-concave lens with negative focal length; the fifth lens is a concave-convex lens with positive focal length; the sixth lens is a concave-concave lens with negative focal length; the seventh lens is a convex-convex lens with positive focal length; the eighth lens is a concave-convex lens with negative focal length; the ninth lens is a convex-convex lens with positive focal length; the tenth lens is a concave-concave lens with negative focal length; the eleventh lens is a convex-convex lens with positive focal length; the twelfth lens is a concave-concave lens with negative focal length; the thirteenth lens is a convex-convex lens with positive focal length; and the fourteenth lens is a convex-convex lens with positive focal length.

[0007] Optionally, at least one of the following conditions is met:

[0008] The first lens and the second lens form a first cemented lens group with positive focal length.

[0009] The sixth lens and the seventh lens form a second cemented lens group with positive optical power;

[0010] The tenth lens and the eleventh lens form a third cemented lens group with positive optical power;

[0011] The twelfth lens and the thirteenth lens form a fourth cemented lens group with negative optical power.

[0012] Optionally, the eighth lens is a glass aspheric lens, the first lens to the seventh lens are glass spherical lenses, and the ninth lens to the fourteenth lens are glass spherical lenses.

[0013] Optionally, the focal length of the second lens group is f (G2) , the focal length of the movie lens with infinite object distance is f inf , the focal length of the movie lens with 1500mm object distance is f 1500 , and the focal length of the lens with 300mm object distance is f 300 , satisfying:

[0014] 0.0015≤|(f (G2) / f inf )-(f (G2) / f 1500 )|≤0.0028;

[0015] 0.0070≤|(f (G2) / f inf )-(f (G2) / f 300 )|≤0.0120.

[0016] Optionally, the first lens and the second lens form a first cemented lens group, the focal length of the first cemented lens group is f (L1-2) , the focal length of the third lens is f (L3) , and the focal length of the fourth lens is f(L4), satisfying:

[0017] 1.250≤|f (L1-2) / (f (L3) +f (L4) )|≤1.7100.

[0018] Optionally, the optical power of the eighth lens is Φ(L8), the optical power of the second lens group is Φ (G2) , and the optical power of the movie lens is Φ, satisfying:

[0019] 0.6000≤Φ (G2) / Φ≤0.6900;

[0020] 0.2300≤|Φ (L8) / Φ (G2) |≤0.5000.

[0021] Optionally, the tenth lens and the eleventh lens constitute a third cemented lens group with positive power;

[0022] A radius of curvature of an image side surface of the ninth lens is R (L9S2) , a radius of curvature of an object side surface of the tenth lens L10 is R (L10S1) , and a power of the third cemented lens group is Φ (L10-11) , satisfying:

[0023] 6.5000≤R (L9S2) -R (L10S1) ≤74.2000.

[0024] 0.0068≤Φ (L10-11) ≤0.0135.

[0025] Optionally, the twelfth lens and the thirteenth lens constitute a fourth cemented lens group with negative power;

[0026] A power of the fourth cemented lens group is Φ (L12-13) , an Abbe number of the eleventh lens is Vd (L11) , an Abbe number of the thirteenth lens is Vd (L13) , and a refractive index of the thirteenth lens L13 is Nd (L13) , satisfying:

[0027] -0.0400≤Φ (L12-13) ≤-0.0310.

[0028] 114.8276≤Vd (L11) +Vd (L13) ≤151.4341.

[0029] 1.4370≤Nd (L13) ≤1.6800.

[0030] Optionally, a radius of curvature of an image side surface of the sixth lens is R (L6S2) , a radius of curvature of an object side surface of the seventh lens is R (L7S1) , an Abbe number of the sixth lens is Vd (L6) , and a refractive index of the sixth lens is Nd (L6) , satisfying:

[0031] 0≤R (L6S2) -R (L7S1) ≤52.0614.

[0032] 0.0160≤Nd (L6) / Vd (L6) ≤0.0510.

[0033] Optionally, the effective net diameter of the first lens is D (L1) , the image size of the movie lens is IH, and the following is satisfied:

[0034] 1.7903<D (L1) / IH<2.4749.

[0035] Embodiments of the present application provide a wide-angle movie lens. The wide-angle movie lens belongs to a fixed focus lens and adopts 14 lenses. The 14 lenses form a fixed group and a focusing group. By setting the surface shape and optical power of the 14 lenses, a 25mm±0.5mm focal length is achieved, and when the illumination is greater than 55%, the distortion at an infinite object distance is less than 2%. Thus, a high-resolution movie lens with wide angle, low distortion and low breathing effect is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 FIG. 1 is a structural schematic diagram of a movie lens at an infinite object distance according to Embodiment 1.

[0037] Figure 2 FIG. 2 is a field curvature curve diagram of the movie lens at the infinite object distance according to Embodiment 1.

[0038] Figure 3 FIG. 3 is a distortion curve diagram of the movie lens at the infinite object distance according to Embodiment 1.

[0039] Figure 4 FIG. 4 is a field curvature curve diagram of the movie lens at a 300mm object distance according to Embodiment 1.

[0040] Figure 5 FIG. 5 is a distortion curve diagram of the movie lens at the 300mm object distance according to Embodiment 1.

[0041] Figure 6 FIG. 6 is an MTF curve diagram of the movie lens at the infinite object distance according to Embodiment 1.

[0042] Figure 7 FIG. 7 is an MTF curve diagram of the movie lens at the 300mm object distance according to Embodiment 1.

[0043] Figure 8 FIG. 8 is a relative illumination diagram of the movie lens at the infinite object distance according to Embodiment 1.

[0044] Figure 9 FIG. 9 is a structural schematic diagram of a movie lens at an infinite object distance according to Embodiment 2.

[0045] Figure 10 FIG. 10 is a field curvature curve diagram of the movie lens at the infinite object distance according to Embodiment 2. FIG. 11 is a distortion curve diagram of the movie lens at the infinite object distance according to Embodiment 2.

[0046] Figure 11 Field curvature plot for the movie lens of Example Two at 300 mm object distance;

[0047] Figure 12 Field curvature plot for the movie lens of Example Two at 300 mm object distance;

[0048] Figure 13 Distortion plot for the movie lens of Example Two at 300 mm object distance;

[0049] Figure 14 MTF plot for the movie lens of Example Two at infinity object distance;

[0050] Figure 15 MTF plot for the movie lens of Example Two at 300 mm object distance;

[0051] Figure 16 Relative illumination plot for the movie lens of Example Two at infinity object distance;

[0052] Figure 17 Schematic diagram of the movie lens of Example Three at infinity object distance;

[0053] Figure 18 Field curvature plot for the movie lens of Example Three at infinity object distance;

[0054] Figure 19 Distortion plot for the movie lens of Example Three at infinity object distance;

[0055] Figure 20 Field curvature plot for the movie lens of Example Three at 300 mm object distance;

[0056] Figure 21 Distortion plot for the movie lens of Example Three at 300 mm object distance;

[0057] Figure 22 MTF plot for the movie lens of Example Three at infinity object distance;

[0058] Figure 23 MTF plot for the movie lens of Example Three at 300 mm object distance;

[0059] Figure 24 Relative illumination plot for the movie lens of Example Three at infinity object distance. DETAILED DESCRIPTION

[0060] The application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are intended to be illustrative only and are not in any way limiting of the application. In addition, it should be understood that the drawings are not necessarily to scale and that, unless otherwise indicated, like components have the same reference numerals throughout the figures.

[0061] Example 1

[0062] Figure 1 For the structure diagram of the movie lens with infinite object distance in Example 1, reference is made to Figure 1 The wide-angle movie lens comprises, in order from the object side to the image side along the optical axis, a first lens group G1 with positive refractive power, a stop STO, and a second lens group G2 with positive refractive power, the first lens group G1 being a fixed group, and the second lens group G2 being a focusing group.

[0063] The first lens group G1 comprises, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7; and the second lens group G2 comprises, in order from the object side to the image side along the optical axis, an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, a twelfth lens L12, a thirteenth lens L13, and a fourteenth lens L14.

[0064] The first lens L1 is a convex-concave lens with negative refractive power; the second lens L2 is a convex-concave lens with positive refractive power, the third lens L3 is a convex-concave lens with negative refractive power; the fourth lens L4 is a convex-concave lens with negative refractive power or a concave-concave lens with negative refractive power; the fifth lens L5 is a concave-convex lens with positive refractive power; the sixth lens L6 is a concave-concave lens with negative refractive power; the seventh lens L7 is a convex-convex lens with positive refractive power; the eighth lens L8 is a concave-convex lens with negative refractive power; the ninth lens L9 is a convex-convex lens with positive refractive power; the tenth lens L10 is a concave-concave lens with negative refractive power; the eleventh lens L11 is a convex-convex lens with positive refractive power; the twelfth lens L12 is a concave-concave lens with negative refractive power; the thirteenth lens L13 is a convex-convex lens with positive refractive power; and the fourteenth lens L14 is a convex-convex lens with positive refractive power. Among them, the object side of the concave-convex lens is concave towards the object side, and the image side of the concave-convex lens is convex towards the image side. The concave-concave lens is a double concave lens. The convex-convex lens is a double convex lens.

[0065] The embodiment of the present application provides a wide-angle movie lens, which belongs to a fixed focus lens and adopts 14 lenses. The 14 lenses form a fixed group and a focusing group. By setting the surface shape and the focal power of the 14 lenses, a 25mm±0.5mm focal length is achieved, and when the illumination is greater than 55%, the distortion of the infinite distance is less than 2%. The wide-angle, low-distortion and low-breathing high-resolution movie lens is achieved. Wherein, 25mm±0.5mm refers to the fluctuation of ±0.5mm near 25mm caused by tolerance.

[0066] Optionally, the wide-angle movie lens satisfies at least one of the following: the first lens L1 and the second lens L2 form a first cemented lens group L1-2 with positive focal power; the sixth lens L6 and the seventh lens L7 form a second cemented lens group L6-7 with positive focal power; the tenth lens L10 and the eleventh lens L11 form a third cemented lens group L10-11 with positive focal power; and the twelfth lens L12 and the thirteenth lens L13 form a fourth cemented lens group L12-13 with negative focal power.

[0067] Optionally, the eighth lens L8 is a glass aspheric lens, the first lens L1 to the seventh lens L7 are glass spherical lenses, and the ninth lens L9 to the fourteenth lens L14 are glass spherical lenses. That is, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are glass spherical lenses. The ninth lens L9, the tenth lens L10, the eleventh lens L11, the twelfth lens L12, the thirteenth lens L13 and the fourteenth lens L14 are glass spherical lenses. In the case of adding an aspheric lens in the rear group (i.e., the second lens group G2) and focusing, the low-breathing effect with a gentle change in angle of view when switching between 0.3m and infinite distance is achieved, and stable high-resolution phenomenon is achieved.

[0068] Optionally, the focal length of the second lens group G2 is f (G2) , the focal length of the movie lens at infinite distance is f inf , the focal length of the movie lens at 1500mm distance is f 1500 , and the focal length of the lens at 300mm distance is f 300 , and the following is satisfied: 0.0015≤|(f (G2) / f inf )-(f (G2) / f 1500 )|≤0.0028; 0.0070≤|(f (G2) / f inf )-(f (G2) / f 300)|≤0.0120. The breathing effect refers to the slight shift in the imaging angle of view (i.e., equivalent focal length) of a cinema lens when the object distance changes. This causes the image to appear slightly zoomed in and out, disrupting the sense of continuity. The smaller the change in focal length at different object distances, the weaker the breathing effect. Therefore, when the above conditions are met, the picture angle changes more gradually. mm stands for millimeters.

[0069] Optionally, the first lens L1 and the second lens L2 form a first cemented lens group L1-2, and the focal length of the first cemented lens group L1-2 is f (L1-2) , the focal length of the third lens L3 is f (L3) , the focal length of the fourth lens L4 is f(L4), satisfying: 1.250≤|f (L1-2) / (f (L3) +f (L4) )|≤1.7100. In this embodiment of the present invention, the optical powers of the first cemented lens group L1-2, the third lens L3, and the fourth lens L4 are positive, negative, and negative, respectively. On this basis, meeting the above conditions allows the wide-angle peripheral field of view light of the cine lens to be rapidly converged and then diverged, allowing it to enter the rear optical system of the lens, thereby improving the peripheral field of view illumination and resolution, and achieving a wide viewing angle.

[0070] Optionally, the focal power of the eighth lens L8 is Φ(L8), and the focal power of the second lens group G2 is Φ (G2) , the focal length of the movie lens is Φ, which satisfies: 0.6000≤Φ (G2) / Φ≤0.6900;0.2300≤|Φ (L8) / Φ (G2) |≤0.5000. The second lens group G2 is the focusing group, accounting for over half of the optical power of the entire cine lens. It focuses light onto the focal plane and, in conjunction with the first lens group G1, significantly reduces field curvature. The glass aspherical surface of the eighth lens element, L8, significantly reduces field of view from the edges of the lens from 0.3m to infinity, ensuring a strong sense of visual continuity and excellent breathing. The resolution at 0.3m and infinity is similar, making the cine lens more versatile.

[0071] Optionally, the tenth lens L10 and the eleventh lens L11 form a third cemented lens group L10-11 with positive optical power; the curvature radius of the image side surface of the ninth lens L9 is R (L9S2) The curvature radius of the object side surface of the tenth lens L10 is R (L10S1) , the optical power of the third cemented lens group L10-11 is Φ (L10-11) , satisfying: 6.5000≤R (L9S2) -R (L10S1) ≤74.2000; 0.0068≤Φ (L10-11)≤0.0135. The ninth lens L9 converges the divergent light rays and produces axial chromatic aberration. The third cemented lens group L10-11 is arranged to reduce the axial chromatic aberration.

[0072] Optionally, the twelfth lens L12 and the thirteenth lens L13 form a fourth cemented lens group L12-13 with negative power; the power of the fourth cemented lens group L12-13 is Φ (L12-13) , the Abbe number of the eleventh lens L11 is Vd (L11) , the Abbe number of the thirteenth lens L13 is Vd (L13) , the refractive index of the thirteenth lens L13 is Nd (L13) , and satisfy: -0.0400≤Φ (L12-13) ≤-0.0310; 114.8276≤Vd (L11) +Vd (L13) ≤151.4341; 1.4370≤Nd (L13) ≤1.6800. The third cemented lens group L10-11 reduces the axial chromatic aberration. The fourth cemented lens group L12-13 is arranged after the third cemented lens group L10-11 to control the light angle, reduce chromatic aberration, flatten the field curvature and compensate for distortion.

[0073] Optionally, the radius of curvature of the image side surface of the sixth lens L6 is R (L6S2) , the radius of curvature of the object side surface of the seventh lens L7 is R (L7S1) , the Abbe number of the sixth lens L6 is Vd (L6) , the refractive index of the sixth lens L6 is Nd (L6) , and satisfy: 0≤R (L6S2) -R (L7S1) ≤52.0614; 0.0160≤Nd (L6) / Vd (L6) ≤0.0510. The closer the radii of curvature of the sixth lens L6 and the seventh lens L7, the better the correction effect on chromatic aberration. The sixth lens L6 is a high Abbe number lens, so the chromatic aberration generated by the front group of light rays is better weakened.

[0074] Optionally, the effective clear aperture of the first lens L1 is D (L1) , and the image size of the movie lens is IH, and satisfy: 1.7903<D (L1)IH<2.4749. The effective net diameter control of the first lens L1 in the embodiment can ensure that the volume of the movie lens is small and convenient for handheld when imaging on a large target, and the user saves cost when configuring a filter piece. The effective net diameter of the lens refers to the diameter of the light passing area actually participating in optical imaging on the lens, that is, the maximum diameter range through which light can pass. For example, the edge part of the lens may not participate in imaging due to mechanical fixation (such as a lens frame, a compression ring) or optical design (such as an aspheric correction area), and the remaining central area is the effective net diameter.

[0075] Exemplarily, the movie lens can further include a flat glass CG located on the side of the fourteenth lens L14 away from the first lens L1, and the flat glass CG is located on the side of the fourteenth lens L14 close to the image surface, so as to protect the photosensitive chip in the imaging sensor. The photosensitive chip is used to convert the light signal collected by the lens into an electrical signal, thereby ensuring the imaging effect of the lens.

[0076] Exemplarily, the aspheric lens (including the glass aspheric lens) satisfies the following formula:

[0077]

[0078] wherein Z is the axial distance of the curved surface at a position along the optical axis direction and perpendicular to the height r of the vertex of the surface; c represents the curvature at the vertex of the aspheric surface; a4, a6, a8, a 10 , a 12 , a 14 are the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, and fourteenth-order high-order aspheric coefficients of the corresponding aspheric surface, and a i r i are combined to form the high-order terms of the corresponding aspheric surface. i are 4, 6, 8, 10, 12, and 14 respectively.

[0079] Table 1 shows a design value of the movie lens in the embodiment one

[0080]

[0081]

[0082] Table 1 shows a design value of the movie lens in the embodiment one, and the specific numerical value can be adjusted according to product requirements, which is not a limitation of the embodiment of the present application. The movie lens shown in Table 1 can be Figure 1A lens generally includes two surfaces, each of which is a refractive surface. The surface numbers in Table 1 are numbered according to the surfaces of each lens. Among them, the surface number S1 represents the front surface (i.e. the object side surface) of the first lens L1, the surface number S2 represents the rear surface (i.e. the image side surface) of the first lens L1, and so on, which will not be repeated here. The radius of curvature represents the bending degree of the lens surface. A positive radius of curvature value indicates that the center of curvature is on the side of the surface close to the image plane IMA, i.e. a positive value represents that the surface is bent towards the image plane IMA; a negative radius of curvature value indicates that the center of curvature is on the side of the surface away from the image plane IMA, i.e. a negative value represents that the surface is bent towards the object plane. “Infinite” in the column of radius of curvature represents that the surface is a plane, and the radius of curvature is infinite, with the unit of mm. The value in the column of thickness represents the center axial distance between the current surface and the next surface, with the unit of mm. The refractive index in the column represents the refractive index of the medium between the current surface and the next surface, which represents the deflection ability of the material between the current surface and the next surface to the light. The space in the column of refractive index represents the refractive index of air, and the refractive index of air is 1. The Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to the light, and the space represents that the current position is air. The half diameter refers to the radius of the lens light passing area (i.e. half of the effective light passing diameter), with the unit of mm.

[0083] Table 2: Aspheric surface coefficients of the movie lens in Example 1

[0084]

[0085] The meaning of the column of “surface number” in Table 2 is consistent with that of the column of “surface number” in Table 1. “E” in each embodiment of the present application represents the base-10 exponent.

[0086] Alternatively, the breathing rate calculation formula when focusing at different object distances is:

[0087]

[0088] where w is the maximum image height half field angle when not at infinity, and w inf is the maximum image height half field angle when at infinity.

[0089] Table 3: System breathing rates of the movie lens in Example 1 at different object distances

[0090] Object distance / mm D13 D26 Maximum image height Half field of view Respiration rate Infinite 17.5357 32.9125 31.6088 - 1500 17.1289 33.3193 31.5754 -0.1056％ 300 15.7251 34.7231 31.4211 -0.5936％

[0091] From Table 3, the absolute value of the respiratory rate is less than 0.6% under different object distances, belonging to a low respiratory effect optical system. D13 and D26 represent the position of the second lens group G2. Even if the movie lens belongs to a fixed focus lens, in order to match different object distances, it is necessary to ensure that the object under different object distances can be clearly imaged on the photosensitive chip. The image distance must be dynamically adjusted by moving the lens (focusing group). Unlike zoom lenses, fixed focus lenses do not have variable magnification lens groups, and fixed focus lenses achieve internal focusing.

[0092] Figure 2 The field curvature curve diagram of the movie lens under the infinite object distance in Example 1; Figure 3 The distortion curve diagram of the movie lens under the infinite object distance in Example 1; Figure 4 The field curvature curve diagram of the movie lens under the 300mm object distance in Example 1; Figure 5 The distortion curve diagram of the movie lens under the 300mm object distance in Example 1; Reference Figures 2-5 In the distortion curve diagram, the horizontal coordinate represents the size of the distortion, and the unit is %; the vertical coordinate represents the normalized image height, and there is no unit; from Figures 2-5 It can be seen that the distortion of the movie lens provided in the embodiment is well corrected from infinity to 300mm, which better ensures the authenticity of object imaging and small imaging distortion. In the field curvature curve diagram, the horizontal coordinate represents the size of the field curvature, and the unit is mm; the vertical coordinate represents the normalized image height, and there is no unit; wherein T represents the meridian, and S represents the sagittal; from Figures 2-5 It can be seen that the field curvature center of the movie lens provided in the embodiment is close to the near edge field, and the difference between the resolution from infinity to 300mm is small.

[0093] Figure 6 The MTF curve diagram of the movie lens under the infinite object distance in Example 1; Figure 7 The MTF curve diagram of the movie lens under the 300mm object distance in Example 1; Reference Figure 6 And Figure 7 The horizontal coordinate is the spatial frequency, which refers to the number of black and white lines per 1mm. The vertical direction is the modulation value (M' / M), M refers to the grating modulation before imaging, and M' refers to the grating modulation after imaging, so 0≤M' / M≤1. The MTF curve diagram represents the resolution of the optical system to the object under different fields of view, meridians and sagittal directions at different frequencies, reflects the imaging degree of the image quality of the object after passing through the optical system, and the higher the MTF, the higher the imaging quality of the lens. From Figure 6 And Figure 7 It can be seen that the MTF of the movie lens under the infinite object distance and the 300mm object distance in all field of view, meridian and sagittal directions is greater than 0.6 when the spatial frequency is 60lp / mm, which has very high imaging effect for the movie lens.

[0094] Figure 8 The relative illumination diagram of the movie lens in Example 1 at infinite object distance; reference Figure 8 The vertical direction is relative illumination, 0 indicates that the field of view has no light passing through at zero illumination; the vertex indicates the maximum illumination, the field of view has no vignetting, and the light is all passing through; the horizontal direction indicates zero field of view to maximum field of view. The larger the relative illumination, the more light passing through, and the less likely to produce a dark corner. From Figure 8 It can be seen that the relative illumination is more than 55%, which is suitable for most cases.

[0095] Example 2

[0096] Similar to the above examples, details are not repeated here.

[0097] Table 4 shows a design value of the movie lens in Example 2

[0098]

[0099]

[0100] Table 4 shows a design value of the movie lens in Example 2, and the specific numerical value can be adjusted according to product requirements, which is not a limitation of the embodiments of the present application. The movie lens shown in Table 4 can be Figure 9 as shown.

[0101] Table 5 shows the aspheric surface coefficients of the movie lens in Example 2

[0102]

[0103] The meaning of "surface number" in Table 5 is consistent with that of "surface number" in Table 4. "E" in each embodiment of the present application represents the base-10 exponent.

[0104] Table 6 shows the system breathing rate of the movie lens in Example 2 at different object distances

[0105] Object distance / mm D13 D26 Maximum image height Half field of view Respiration rate Infinite 11.9837 31.6645 31.4790 - 1500 11.5736 32.0746 31.4438 -0.1117％ 300 10.1062 33.5421 31.2821 -0.6254％

[0106] From Table 6, it can be seen that the absolute value of the breathing rate at different object distances is less than 0.65%, which belongs to a low-breathing-effect optical system.

[0107] Figure 14 The MTF curve diagram of the movie lens in Example 2 at infinite object distance; Figure 15 The MTF curve diagram of the movie lens in Example 2 at 300mm object distance; reference Figure 14 and Figure 15 The MTF of the movie lens at infinite object distance and 300mm object distance in all field of view meridian and sagittal directions is greater than 0.5 at a spatial frequency of 60lp / mm, which has very high imaging effect for the movie lens.

[0108] Example Three

[0109] Similarities with the above examples are not repeated here.

[0110] Table 7 Design values of a movie lens in Example Three

[0111]

[0112]

[0113] Table 7 shows the design values of a movie lens in Example Three, which can be adjusted according to product requirements, and is not a limitation on the embodiments of the present application. The movie lens shown in Table 7 can be as shown in Table 8. Figure 17

[0114] Table 8 Aspheric surface coefficients of the movie lens in Example Three

[0115]

[0116] The meaning of the column of "surface number" in Table 8 is consistent with that of "surface number" in Table 7. "E" in each embodiment of the present application represents the base-10 exponent.

[0117] Table 9 System breathing rate of the movie lens in Example Three at different object distances

[0118] Object distance / mm D13 D26 Maximum image height Half field of view Respiration rate Infinite 11.4257 33.6837 31.9960 - 1500 11.0397 34.0697 31.9887 -0.0228％ 300 9.7272 35.3822 31.9257 -0.2197％

[0119] As can be seen from Table 9, the absolute value of the breathing rate is less than 0.25% at different object distances, which belongs to a low-breathing-effect optical system.

[0120] Figure 22 Figure 7 is an MTF curve diagram of the movie lens in Example Three at an infinite object distance; Figure 23 Figure 8 is an MTF curve diagram of the movie lens in Example Three at an object distance of 300 mm; reference Figure 22 and Figure 23 The MTF of the movie lens at an infinite object distance and at an object distance of 300 mm in all field of view meridian and sagittal directions is greater than 0.5 at a spatial frequency of 60 lp / mm, which has a very high imaging effect for the movie lens.

[0121] Table 10 Parameter design values of each embodiment

[0122]

[0123]

[0124] ​Note that the above merely describes preferred embodiments of the present application and the principles of the technology applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and that various obvious changes, modifications, combinations and substitutions can be made by those skilled in the art without departing from the scope of the present application. Therefore, although the present application has been described in detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the claims.

Claims

1. A wide-angle movie lens, characterized in that: The optical system comprises a first lens group with positive focal length, an aperture, and a second lens group with positive focal length, which are arranged in sequence from the object side to the image side along the optical axis, wherein the first lens group is a fixed lens group and the second lens group is a focusing lens group; The first lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged in sequence from the object side to the image side along the optical axis; the second lens group includes an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, and a fourteenth lens arranged in sequence from the object side to the image side along the optical axis; The first lens is a convex-concave lens with negative optical power; the second lens is a convex-concave lens with positive optical power; the third lens is a convex-concave lens with negative optical power; the fourth lens is a convex-concave lens with negative optical power or a concave-concave lens with negative optical power; the fifth lens is a concave-convex lens with positive optical power; the sixth lens is a concave-concave lens with negative optical power; the seventh lens is a convex-convex lens with positive optical power; the eighth lens is a concave-convex lens with negative optical power; the ninth lens is a convex-convex lens with positive optical power; the tenth lens is a concave-concave lens with negative optical power; the eleventh lens is a convex-convex lens with positive optical power; the twelfth lens is a concave-concave lens with negative optical power; the thirteenth lens is a convex-convex lens with positive optical power; and the fourteenth lens is a convex-convex lens with positive optical power.

2. The wide-angle movie lens according to claim 1, characterized in that: Satisfy at least one of the following: The first lens and the second lens form a first cemented lens group with positive optical power; The sixth lens and the seventh lens form a second cemented lens group with positive optical power; The tenth lens and the eleventh lens form a third cemented lens group with positive optical power; The twelfth lens and the thirteenth lens form a fourth cemented lens group with negative optical power.

3. The wide-angle movie lens according to claim 1, wherein: The eighth lens is a glass aspherical lens, the first to seventh lenses are glass spherical lenses, and the ninth to fourteenth lenses are glass spherical lenses.

4. The wide-angle movie lens according to claim 1, wherein: The focal length of the second lens group is f (G2) , the focal length of the movie lens at infinite object distance is f inf The focal length of the movie lens at an object distance of 1500 mm is f 1500 , the focal length of the lens at 300mm object distance is f 300 ,satisfy: 0.0015≤|(f (G2) / f inf )-(f (G2) / f 1500 )|≤0.0028; 0.0070≤|(f (G2) / f inf )-(f (G2) / f 300 )|≤0.0120。 5. The wide-angle movie lens according to claim 1, wherein: The first lens and the second lens form a first cemented lens group, and the focal length of the first cemented lens group is f (L1-2) , the focal length of the third lens is f (L3) , the focal length of the fourth lens is f(L4), satisfying: 1.250≤|f (L1-2) / (f (L3) +f (L4) )|≤1.7100。 6. The wide-angle movie lens according to claim 3, wherein: The focal power of the eighth lens is Φ(L8), and the focal power of the second lens group is Φ (G2) , the optical power of the movie lens is Φ, which satisfies: 0.6000≤Φ (G2) / Φ≤0.6900; 0.2300≤|Φ (L8) / F (G2) |≤0.5000。 7. The wide-angle movie lens according to claim 1, wherein: The tenth lens and the eleventh lens form a third cemented lens group with positive optical power; The curvature radius of the image side surface of the ninth lens is R (L9S2) The curvature radius of the object side surface of the tenth lens L10 is R (L10S1) , the optical power of the third cemented lens group is Φ (L10-11) ,satisfy: 6.5000≤R (L9S2) -R (L10S1) ≤74.2000; 0.0068≤Φ (L10-11) ≤0.0135。 8. The wide-angle movie lens according to claim 7, characterized in that: The twelfth lens and the thirteenth lens form a fourth cemented lens group with negative optical power; The optical power of the fourth cemented lens group is Φ (L12-13) , the Abbe number of the eleventh lens is Vd (L11) , the Abbe number of the thirteenth lens is Vd (L13) The refractive index of the thirteenth lens L13 is Nd (L13) ,satisfy: -0.0400≤Φ (L12-13) ≤-0.0310; 114.8276≤Vd (L11) +CEO (L13) ≤151.4341; 1.4370≤Nd (L13) ≤1.6800。 9. The wide-angle movie lens according to claim 1, wherein: The curvature radius of the image side surface of the sixth lens is R (L6S2) The curvature radius of the object side of the seventh lens is R (L7S1) , the Abbe number of the sixth lens is Vd (L6) , the refractive index of the sixth lens is Nd (L6) ,satisfy: 0≤R (L6S2) -R (L7S1) ≤52.0614; 0.0160≤Nd (L6) / CEO (L6) ≤0.0510。 10. The wide-angle movie lens according to claim 1, wherein: The effective net diameter of the first lens is D (L1) , the image plane size of the movie lens is IH, which satisfies: 1.7903<D (L1) / IH<2.4749。

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