A wide-angle cine lens

Abstract

The present application provides a kind of wide-angle movie lens, first lens is the convex-concave lens of negative power;Second lens is the convex-concave lens of positive power, third lens is the convex-concave lens of negative power;Fourth lens is the convex-concave lens of negative power or is the concave-concave lens of negative power;Fifth lens is the concave-convex lens of positive power;Sixth lens is the concave-concave lens of negative power;Seventh lens is the convex-convex lens of positive power;Eighth lens is the concave-convex lens of negative power;Ninth lens is the convex-convex lens of positive power;Tenth lens is the concave-concave lens of negative power;Eleventh lens is the convex-convex lens of positive power;Twelfth lens is the concave-concave lens of negative power;Thirteenth lens is the convex-convex lens of positive power;Fourteenth lens is the convex-convex lens of positive power.This embodiment realizes wide-angle, low distortion, low breathing effect high resolution movie lens.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, and more particularly to a wide-angle cinema lens. Background Technology

[0002] In recent years, cinema lenses have become one of the mainstream methods of filmmaking due to their excellent balance between image quality and high-resolution shooting capabilities. Wide-angle lenses are crucial in film storytelling, but currently, wide-angle cinema lenses exhibit significant distortion, and post-processing correction can result in a loss of image quality and perspective. Furthermore, the visual continuity is weak when the focus shifts at different object distances, placing extremely high demands on the breathing effect. Additionally, close-up resolution is not adequately considered when switching object distances, leading to unstable image quality with varying object distances. Summary of the Invention

[0003] This invention provides a wide-angle cinema lens to achieve a high-resolution cinema lens with wide angle, low distortion, and low breathing effect.

[0004] This invention provides a wide-angle cinema lens, comprising a first lens group of positive optical power, an aperture stop, and a second lens group of positive optical power arranged sequentially 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 includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the optical axis from the object side to the image side; 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 sequentially along the optical axis from the object side to the image side.

[0006] 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 either 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.

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

[0008] The first lens and the second lens together form a first cemented lens group with positive optical power;

[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 together form a fourth cemented lens group with negative optical power.

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

[0013] Optionally, the focal length of the second lens group is f (G2) The focal length of the movie lens at infinity is f. inf The focal length of the cinema lens at a 1500mm object distance is f. 1500 The focal length of the lens at a 300mm object distance is f. 300 ,satisfy:

[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, 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), which satisfies:

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

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

[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 form a third cemented lens group with positive optical power;

[0022] The radius of curvature of the image-side surface of the ninth lens is R. (L9S2) The radius of curvature 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:

[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 form a fourth cemented lens group with negative optical power;

[0026] 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:

[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, the radius of curvature of the image-side surface of the sixth lens is R. (L6S2) The radius of curvature of the object-side surface 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:

[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, satisfying:

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

[0035] This invention provides a wide-angle cinema lens, which is a fixed-focus lens employing 14 lenses. These 14 lenses form a fixed group and a focusing group. By setting the surface shape and optical power of the 14 lenses, a focal length of 25mm ± 0.5mm is achieved, with infinity distortion less than 2% at illuminance greater than 55%. This results in a high-resolution cinema lens with wide angle, low distortion, and low breathing effect. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of a movie lens at infinity distance in Example 1;

[0037] Figure 2 This is a field curvature curve diagram of a movie shot at infinity object distance in Example 1;

[0038] Figure 3 This is a distortion curve of a movie lens at infinity object distance in Example 1;

[0039] Figure 4 This is a field curvature curve of a movie lens at a distance of 300mm in Example 1;

[0040] Figure 5 This is a distortion curve of the cinema lens at a 300mm object distance in Example 1.

[0041] Figure 6 This is the MTF curve of the movie lens at infinity object distance in Example 1;

[0042] Figure 7 This is the MTF curve of the cinema lens at a 300mm object distance in Example 1;

[0043] Figure 8 This is a relative illumination diagram of a movie lens at infinity distance in Example 1;

[0044] Figure 9 This is a schematic diagram of the structure of the movie lens at infinity distance in Example 2;

[0045] Figure 10 This is a field curvature curve diagram of a movie shot at infinity object distance in Example 2;

[0046] Figure 11 This is a distortion curve of a movie lens at infinity object distance in Example 2;

[0047] Figure 12 This is a field curvature curve of a movie lens at a distance of 300mm in Example 2;

[0048] Figure 13 This is a distortion curve of the cinema lens at an object distance of 300mm in Example 2;

[0049] Figure 14 This is the MTF curve of the movie lens at infinity object distance in Example 2;

[0050] Figure 15 This is the MTF curve of the cinema lens at a distance of 300mm in Example 2;

[0051] Figure 16 This is a relative illumination diagram of a movie lens at infinity distance in Example 2;

[0052] Figure 17 This is a schematic diagram of the structure of a movie lens at infinity distance in Example 3;

[0053] Figure 18 This is a field curvature curve diagram of a movie shot at infinity object distance in Example 3;

[0054] Figure 19 This is a distortion curve of a movie lens at infinity object distance in Example 3;

[0055] Figure 20 This is a field curvature curve of a movie lens at a distance of 300mm in Example 3;

[0056] Figure 21 This is a distortion curve of the cinema lens at an object distance of 300mm in Example 3;

[0057] Figure 22 This is the MTF curve of the movie lens at infinity object distance in Example 3;

[0058] Figure 23 This is the MTF curve of the cinema lens at a distance of 300mm in Example 3;

[0059] Figure 24 This is a relative illumination diagram of a movie lens at infinity distance in Example 3. Detailed Implementation

[0060] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0061] Example 1

[0062] Figure 1 This is a schematic diagram of the structure of a movie lens at infinity object distance in Example 1, for reference. Figure 1 The wide-angle cinema lens includes a first lens group G1 with positive optical power, an aperture stop STO, and a second lens group G2 with positive optical power, arranged sequentially from the object side to the image side along the optical axis. The first lens group G1 is a fixed group, and the second lens group G2 is a focusing group.

[0063] The first lens group G1 includes 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 arranged sequentially along the optical axis from the object side to the image side; the second lens group G2 includes 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 arranged sequentially along the optical axis from the object side to the image side.

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

[0065] This invention provides a wide-angle cinema lens, which is a fixed-focus lens employing 14 lenses. These 14 lenses form a fixed group and a focusing group. By setting the surface shape and optical power of the 14 lenses, a focal length of 25mm ± 0.5mm is achieved, with infinity distortion less than 2% at illuminance greater than 55%. This results in a high-resolution cinema lens with wide angle, low distortion, and low breathing effect. The 25mm ± 0.5mm refers to a fluctuation of ±0.5mm around 25mm due to tolerance.

[0066] Optionally, the wide-angle cinema 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 optical power; the sixth lens L6 and the seventh lens L7 form a second cemented lens group L6-7 with positive optical power; the tenth lens L10 and the eleventh lens L11 form a third cemented lens group L10-11 with positive optical power; and the twelfth lens L12 and the thirteenth lens L13 form a fourth cemented lens group L12-13 with negative optical power.

[0067] Optionally, the eighth lens L8 is a glass aspherical 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. By adding aspherical lenses to the rear group (i.e., the second lens group G2) and focusing, a low breathing effect with a smooth change in the image angle is achieved when switching between object distances of 0.3m and infinity, resulting in stable high resolution.

[0068] Optionally, the focal length of the second lens group G2 is f (G2) The focal length of a movie lens at infinity is f. inf The focal length of a movie lens with a 1500mm object distance is f. 1500 The focal length of the lens at a 300mm object distance is f. 300 Satisfying: 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 change in the imaging angle (i.e., equivalent focal length) when the object distance of a movie lens changes, resulting in a slight scaling of the image and disrupting the continuity of the shot. The smaller the change in focal length between different object distances, the weaker the breathing effect. Therefore, when the above conditions are met, the change in the angle of view is more gradual. Where mm represents 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), which satisfies: 1.250 ≤ |f (L1-2) / (f (L3) +f (L4) )|≤1.7100. In this embodiment of the invention, the optical power of the first cemented lens group L1-2, the third lens L3 and the fourth lens L4 are positive, negative and negative, respectively. Based on this, under the above conditions, the large-angle field of view light rays at the edge of the movie lens can be quickly gathered and then diverged, so that they can enter the optical system at the rear of the lens, thereby improving the edge field of view illumination and resolution, and achieving a wide viewing angle.

[0070] Optionally, the optical power of the eighth lens L8 is Φ(L8), and the optical power of the second lens group G2 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) / Φ (G2) |≤0.5000. The second lens group G2 is the focusing group, accounting for more than half of the optical power of the entire cinema lens. It focuses light onto the focal plane and, together with the first lens group G1, greatly helps with field curvature distortion. Furthermore, with the addition of the eighth lens L8 aspherical glass, the change in edge field of view is minimal from 0.3m to infinity, resulting in strong visual continuity and good breathing effect. The resolution at 0.3m is not significantly different from that at infinity, broadening the application scenarios of the cinema lens.

[0071] Optionally, the tenth lens L10 and the eleventh lens L11 form a third cemented lens group L10-11 with positive optical power; the radius of curvature of the image side surface of the ninth lens L9 is R. (L9S2) The radius of curvature 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 will cause axial chromatic aberration after it converges the diverging light. The presence of the third cemented lens group L10-11 will bring the focal points of different wavelengths closer together, effectively reducing axial chromatic aberration.

[0072] Optionally, the twelfth lens L12 and the thirteenth lens L13 form a fourth cemented lens group L12-13 with negative optical power; the optical 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) Satisfying: -0.0400≤Φ (L12-13) ≤-0.0310; 114.8276≤Vd (L11) +Vd (L13) ≤151.4341; 1.4370≤Nd (L13) ≤1.6800. Based on the reduction of axial chromatic aberration by the third cemented lens group L10-11, the fourth cemented lens group L12-13 can be added after the third cemented lens group L10-11 to control the light refraction angle, reduce chromatic aberration, smooth 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) Satisfying: 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 are, the better the correction effect on chromatic aberration. Moreover, the sixth lens L6 is a high Abbe number lens, so it better weakens the chromatic aberration caused by the front group light.

[0074] Optionally, the effective net diameter of the first lens L1 is D. (L1) The image size of the movie lens is IH, which satisfies: 1.7903 <D (L1) / IH<2.4749. This embodiment controls the effective net diameter of the first lens L1, ensuring a compact size and easy handheld operation when imaging large target surfaces, saving costs for users when configuring filters. The effective net diameter of the lens refers to the diameter of the light-transmitting area that actually participates in optical imaging, i.e., the maximum diameter range through which light can pass. For example, due to mechanical fixation (such as the frame or retaining ring) or optical design (such as aspherical correction areas), the edge portion of the lens may not participate in imaging; the remaining central area is the effective net diameter.

[0075] For example, the cinema lens may further include a flat glass CG, which is located on the side of the fourteenth lens L14 away from the first lens L1 and on the side of the fourteenth lens L14 adjacent to the image plane, to protect the photosensitive chip in the imaging sensor. The photosensitive chip is used to convert the light signals collected by the lens into electrical signals, thereby ensuring the imaging effect of the lens.

[0076] For example, an aspherical lens (including a glass aspherical lens) satisfies the following formula:

[0077]

[0078] Where Z is the axial distance from the vertex of the surface at a position perpendicular to the optical axis and at a height r along the optical axis; c represents the curvature at the vertex of the aspherical surface; a4, a6, a8, a 10 a 12 a 14 For the higher-order aspheric coefficients corresponding to the fourth, sixth, eighth, tenth, twelfth, and fourteenth orders of aspheric surfaces, a i r i These are combined to form higher-order terms for the corresponding aspherical surfaces. The values ​​of i are 4, 6, 8, 10, 12, and 14.

[0079] Table 1. Design values ​​for a movie lens in Example 1.

[0080]

[0081]

[0082] Table 1 shows one design value for the cinematic lens in Embodiment 1. The specific values ​​can be adjusted according to product requirements and are not intended to limit the embodiments of the present invention. The cinematic lens shown in Table 1 can be... Figure 1As shown in Table 1, a lens generally consists of two surfaces, each serving as a refractive surface. The surface numbers in Table 1 are assigned based on the surfaces of each lens. Surface number S1 represents the front surface (object side) of the first lens L1, surface number S2 represents the rear surface (image side) of the first lens L1, and so on. The radius of curvature represents the degree of curvature of the lens surface. A positive radius of curvature value indicates that the center of curvature is on the side of the surface closer to the image plane IMA; a negative radius of curvature value indicates that the center of curvature is on the side of the surface farther from the image plane IMA. "Infinite" in the radius of curvature column indicates that the surface is planar with an infinite radius of curvature, expressed in mm. The value in the thickness column represents the axial distance between the current surface and the next surface, expressed in mm. The refractive index column represents the refractive index of the medium between the current and next surfaces, representing the material's ability to deflect light between them. The blank space in the refractive index column represents the refractive index of air, which is 1. The Abbe number represents the dispersion characteristics of light by the material between the current surface and the next surface; a blank space indicates the current location is air. Half-diameter refers to the radius of the lens's light-transmitting area (i.e., half the effective light-transmitting diameter), measured in mm.

[0083] Table 2 Aspherical coefficients of the cinema lens in Example 1

[0084]

[0085] The meaning of the "Surface Number" column in Table 2 is consistent with that in Table 1. In the embodiments of this invention, "E" represents a base-10 exponent.

[0086] Optionally, the formula for calculating the breathing rate when focusing at different object distances is:

[0087]

[0088] Where w is the maximum image height half-field angle when it is not at infinity, w inf The maximum image height half-field angle at infinity.

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

[0090] Object distance / mm D13 D26 Maximum image height half field of view respiratory 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] Table 3 shows that the absolute value of the breathing rate is less than 0.6% at different object distances, classifying it as a low breathing effect optical system. D13 and D26 indicate the position of the second lens group G2. Even though cinema lenses are fixed-focus lenses, to match different object distances and ensure that objects at different object distances are clearly imaged on the image sensor, the image distance must be dynamically adjusted by moving the lens elements (focus group). Unlike zoom lenses, fixed-focus lenses do not have a zoom lens group, and they achieve internal focusing.

[0092] Figure 2 This is a field curvature curve diagram of a movie shot at infinity object distance in Example 1; Figure 3 This is a distortion curve of a movie lens at infinity object distance in Example 1; Figure 4 This is a field curvature curve of a movie lens at a distance of 300mm in Example 1; Figure 5 This is a distortion curve of a cinema lens at a 300mm object distance in Example 1; for reference Figures 2-5 In the distortion curve diagram, the horizontal axis represents the magnitude of distortion, in percentage; the vertical axis represents the normalized image height, which has no unit; from Figures 2-5 As can be seen, the distortion of the movie lens provided in this embodiment is well corrected from infinity to 300mm, ensuring good image realism and minimizing image distortion. In the field curvature curve diagram, the horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height (unitless); where T represents the meridion and S represents the sagitta; from... Figures 2-5 It can be seen that the resolution difference between the field curvature center and the near edge of the field of view of the movie lens provided in this embodiment is small from infinity to 300mm.

[0093] Figure 6 This is the MTF curve of the movie lens at infinity object distance in Example 1; Figure 7 This is the MTF curve of the cinema lens at a 300mm object distance in Example 1; Reference Figure 6 and Figure 7 The horizontal axis represents spatial frequency, indicating the number of black and white line pairs per millimeter. The vertical axis represents the modulation modulus (M' / M), where M refers to the grating modulation degree before imaging, and M' refers to the grating modulation degree after imaging; therefore, 0 ≤ M' / M ≤ 1. The MTF curve represents the resolving power of an optical system for an object at different frequencies in different fields of view, meridional, and sagittal directions. It reflects the degree of image quality after the object passes through the optical system; the higher the MTF, the higher the image quality of the lens. From... Figure 6 and Figure 7 It can be seen that the MTF of the movie lens in all fields of view along the meridional and sagittal directions at infinity and 300mm object distances is greater than 0.6 at a spatial frequency of 60lp / mm, which indicates that the movie lens has a very high imaging effect.

[0094] Figure 8 This is a relative illumination diagram of a movie lens at infinity distance in Example 1; for reference. Figure 8 The vertical direction represents relative illuminance, with 0 indicating zero illuminance and no light passing through the field of view; the vertex represents maximum illuminance, where there is no vignetting and all light passes through; the horizontal direction represents the range from zero field of view to maximum field of view. The greater the relative illuminance, the more light passes through, and the less likely vignetting is to occur. Figure 8 As can be seen, the relative illumination is above 55%, making it suitable for most situations.

[0095] Example 2

[0096] Similarities to the above embodiments will not be repeated here.

[0097] Table 4. One design value for a movie lens in Example 2.

[0098]

[0099]

[0100] Table 4 shows one design value for the cinematic lens in Embodiment 2. The specific values ​​can be adjusted according to product requirements and are not intended to limit the embodiments of the present invention. The cinematic lens shown in Table 4 can be... Figure 9 As shown.

[0101] Table 5 Aspherical coefficients of the cinema lens in Example 2

[0102]

[0103] The meaning of the "Surface Number" column in Table 5 is consistent with that in Table 4. In the embodiments of this invention, "E" represents a base-10 exponent.

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

[0105] Object distance / mm D13 D26 Maximum image height half field of view respiratory 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] As shown in Table 6, the absolute value of the respiration rate is less than 0.65% at different object distances, which indicates that it belongs to a low respiration effect optical system.

[0107] Figure 14 This is the MTF curve of the movie lens at infinity object distance in Example 2; Figure 15 This is the MTF curve of the cinema lens at a 300mm object distance in Example 2; Reference Figure 14 and Figure 15 The MTF of this cinema lens in all fields of view, both in the meridional and sagittal directions, at a spatial frequency of 60 lp / mm, is greater than 0.5 at infinity and 300 mm object distances, resulting in a very high imaging effect for cinema lenses.

[0108] Example 3

[0109] Similarities to the above embodiments will not be repeated here.

[0110] Table 7. One design value for a movie lens in Example 3.

[0111]

[0112]

[0113] Table 7 shows one design value for the cinematic lens in Embodiment 3. The specific values ​​can be adjusted according to product requirements and are not intended to limit the embodiments of the present invention. The cinematic lens shown in Table 7 can be... Figure 17 As shown.

[0114] Table 8 Aspherical coefficients of the cinema lens in Example 3

[0115]

[0116] The meaning of the "Face Number" column in Table 8 is consistent with that in Table 7. In the embodiments of this invention, "E" represents a base-10 exponent.

[0117] Table 9. System breathing rate at different object distances for cinema lenses in Example 3.

[0118] Object distance / mm D13 D26 Maximum image height half field of view respiratory 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 shown in Table 9, the absolute value of the respiration rate is less than 0.25% at different object distances, which indicates that it belongs to a low respiration effect optical system.

[0120] Figure 22 This is the MTF curve of the movie lens at infinity object distance in Example 3; Figure 23 This is the MTF curve of the cinema lens at a 300mm object distance in Example 3; Reference Figure 22 and Figure 23 The MTF of this cinema lens in all fields of view, both in the meridional and sagittal directions, at a spatial frequency of 60 lp / mm, is greater than 0.5 at infinity and 300 mm object distances, resulting in a very high imaging effect for cinema lenses.

[0121] Table 10 Parameter design values ​​for each embodiment

[0122]

[0123]

[0124] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A wide-angle cinema lens, characterized in that, It includes a first lens group with positive optical power, an aperture, and a second lens group with positive optical power arranged sequentially from the object side to the image side along the optical axis. The first lens group is a fixed group, and the second lens group is a focusing 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 sequentially along the optical axis from the object side to the image side; 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 sequentially along the optical axis from the object side to the image side. 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 either 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 cinema lens according to claim 1, characterized in that, At least one of the following must be met: The first lens and the second lens together 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 together form a fourth cemented lens group with negative optical power.

3. The wide-angle cinema lens according to claim 1, characterized in that, The eighth lens is a glass aspherical lens, the first to the seventh lenses are glass spherical lenses, and the ninth to the fourteenth lenses are glass spherical lenses.

4. The wide-angle cinema lens according to claim 1, characterized in that, The focal length of the second lens group is f (G2) The focal length of the movie lens at infinity is f. inf The focal length of the cinema lens at a 1500mm object distance is f. 1500 The focal length of the lens at a 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 cinema lens according to claim 1, characterized in that, 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), which satisfies: 1.250≤|f (L1-2) / (f (L3) +f (L4) )|≤1.7100。 6. The wide-angle cinema lens according to claim 3, characterized in that, The optical power of the eighth lens is Φ(L8), and the optical 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 cinema lens according to claim 1, characterized in that, The tenth lens and the eleventh lens form a third cemented lens group with positive optical power; The radius of curvature of the image-side surface of the ninth lens is R. (L9S2) The radius of curvature of the object-side surface of the tenth lens 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 cinema lens according to claim 7, characterized in that, The twelfth lens and the thirteenth lens together 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 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 cinema lens according to claim 1, characterized in that, The radius of curvature of the image-side surface of the sixth lens is R. (L6S2) The radius of curvature of the object-side surface 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 cinema lens according to claim 1, characterized in that, The effective net diameter of the first lens is D (L1) The image size of the movie lens is IH, satisfying: 1.7903<D (L1) / IH<2.4749。

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