An ultra-wide-angle large aperture anamorphic lens

Abstract

The present invention discloses an ultra-wide-angle large-aperture anamorphic lens, comprising a cylindrical lens group and a spherical lens group arranged in sequence from the object side to the image side; the cylindrical lens group comprises a first lens, a second lens, a third lens and a fourth lens arranged in sequence, the first lens and the second lens are negative-power cylindrical lenses, and the third lens and the fourth lens are positive-power cylindrical lenses; the spherical lens group sequentially arranges a fifth lens, a sixth lens, ..., a thirteenth lens along the direction of the light path pointing to the image side. This anamorphic lens corrects the overall aberration of four cylindrical lenses and nine spherical lenses, thereby increasing the field angle of the lens for horizontal shooting, making the width of the actual shot picture larger, and obtaining a 2.4:1 wide-screen video or photo without sacrificing pixels; at the same time, because the anamorphic lens is a front-end anamorphic design, in addition to the anamorphic function, it also has optical characteristics such as elliptical out-of-focus light spots and sci-fi line flares.

Description

Technical Field

[0001] The present invention relates to the technical field of lenses, and in particular to a half-frame large aperture anamorphic lens with a focal length of 24 mm. Background Art

[0002] With the rapid development of Internet technology, taking photos and videos have become an indispensable part of the lives of ordinary consumers. In recent years, with the promotion of technologies such as 5G, more and more videos such as Vlog are shared, and more and more people are using mobile phones, cameras and other tools to shoot short videos and micro-movies.

[0003] However, the conventional shooting ratio of mobile phones, tablets, cameras and other devices on the market is 16:9, while the ratio of wide-screen videos with a cinematic feel is 2.4:1. At the same time, good micro-film or video shooting requires the cooperation of anamorphic lenses of different focal lengths, among which ultra-wide-angle anamorphic lenses are indispensable in shooting.

[0004] Some professional anamorphic movie lens brands include: Hawk from Germany, Cooke from the UK, ARRI from Germany, Panavison from the US, Angenieux from France and SLR from Hong Kong, China. The ultra-wide-angle anamorphic lenses of these brands are usually aimed at professional customers. They are not only expensive but also cannot be carried around at all times due to their size and weight.

[0005] Professional anamorphic lenses are expensive and heavy, so they are not suitable for ordinary users. Therefore, how to reduce the size and weight of ultra-wide-angle and large-aperture anamorphic lenses, which are very important in video shooting, is a technical problem that needs to be solved. Summary of the invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the professional ultra-wide-angle large aperture anamorphic lens in the prior art that it is heavy in weight and high in price and is not suitable for use by ordinary users, thereby providing a lightweight ultra-wide-angle large aperture anamorphic lens.

[0007] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0008] An ultra-wide-angle large-aperture anamorphic lens, comprising a cylindrical lens group and a spherical lens group arranged in sequence from the object side to the image side; the cylindrical lens group comprises a first lens, a second lens, a third lens and a fourth lens arranged in sequence from the object side to the image side, the first lens and the second lens are negative-power cylindrical lenses, and the third lens and the fourth lens are positive-power cylindrical lenses; wherein a generatrix of the fourth lens is perpendicular to a generatrix of the third lens; the spherical lens group is arranged in sequence along a direction of an optical path pointing to the image side, a fifth lens, a sixth lens, ..., an Nth lens; wherein N is a natural number greater than or equal to 10;

[0009] The focal power distribution of the lenses constituting the cylindrical lens group and the spherical lens group satisfies the following relationship:

[0010] 23.6mm<f (1－N) Y<24.4mm;

[0011] 17.6mm<f (1－N) X<19.2mm;

[0012] 1.20<f (1－N) Y / f (1－N) X<1.40;

[0013] 3.50<f 4 Y / f (2－3) X<4.20;

[0014] The X direction is defined as the curvature direction of the first lens, and the Y direction is defined as another direction that is 90 degrees to the curvature direction of the first lens; wherein the subscript numerals of f represent the numbers of the lenses constituting the anamorphic lens, and f (M－N) Y represents the combined optical focal length of the Mth lens to the Nth lens (N-M+1) in the Y direction, f (M－N) X represents the combined optical focal length of the M-th lens to the N-th lens (N-M+1) lenses in the X direction; M is a natural number greater than or equal to 1 and less than N.

[0015] Furthermore, the spherical lens group is sequentially provided with a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens and a thirteenth lens along the direction of the optical path pointing to the image side.

[0016] Further, the first lens is used as a front fixed group of the anamorphic lens, the second lens to the sixth lens are used as an inner focusing group of the anamorphic lens, and the seventh lens to the thirteenth lens are used as a rear fixed group of the anamorphic lens; wherein the optical power distribution of the front fixed group, the inner focusing group and the rear fixed group satisfies the following relationship:

[0017] -3.10<f 1 X / f (1－13) X<-2.70;

[0018] -2.10<f (2－6) Y / f (1－13) Y<-1.60;

[0019] -10.20<f (2－6) X / f (1－13) X<-9.20;

[0020] 2.40<f (7－13) X / f(1－13) X<2.80;

[0021] The X direction is defined as the curvature direction of the first lens, and the Y direction is defined as another direction that is 90 degrees to the curvature direction of the first lens; wherein the subscript numerals of f represent the numbers of the lenses constituting the anamorphic lens, and f (M－N) Y represents the combined optical focal length of the Mth lens to the Nth lens (N-M+1) in the Y direction, f (M－N) X represents the combined optical focal length of the M-th lens to the N-th lens (N-M+1) lenses in the X direction; M is a natural number greater than or equal to 1 and less than N.

[0022] Further, the fifth lens, the ninth lens and the tenth lens are all spherical lenses with negative optical power, and the sixth lens, the seventh lens, the eighth lens, the eleventh lens, the twelfth lens and the thirteenth lens are all spherical lenses with positive optical power.

[0023] Furthermore, a generatrix of the fourth lens is perpendicular to a generatrix of the third lens.

[0024] Furthermore, the second lens and the third lens are bonded together.

[0025] Furthermore, the eighth lens and the ninth lens are bonded together.

[0026] Furthermore, the tenth lens and the eleventh lens are bonded together.

[0027] Furthermore, the length of the anamorphic lens is less than 130 mm, and the front end can match a universal filter with a diameter of 67 mm.

[0028] Furthermore, the focal length of the anamorphic lens in the Y direction is 24.4 mm, the focal length in the X direction is 18.3 mm, and the aperture is 2.8.

[0029] Furthermore, the mass of the anamorphic lens is less than 750g.

[0030] The technical solution of the present invention has the following advantages:

[0031] 1. The ultra-wide-angle large aperture anamorphic lens provided by the present invention uses an overall design method to correct the overall aberration of four cylindrical lenses and nine spherical lenses, thereby increasing the field of view of the lens for horizontal shooting and making the width of the actual shot larger. No post-editing is required, and 2.4:1 widescreen videos or photos can be obtained without sacrificing pixels. At the same time, because the scheme is a front-end anamorphic design, the anamorphic lens of this scheme will have optical characteristics such as elliptical out-of-focus spots and sci-fi line flares in addition to the anamorphic function.

[0032] 2. The ultra-wide-angle and large-aperture anamorphic lens provided by the present invention has a unique optical structure and adopts an integrated design of cylindrical lenses in the X direction and the Y direction, wherein the generatrix of the first lens, the second lens and the third lens are parallel to each other, and the generatrix of the fourth lens is perpendicular to the generatrix of the first three cylindrical lenses; due to the non-rotationally symmetric optical properties of the cylindrical lenses, adding the Y-direction cylindrical lens is beneficial to the correction of the astigmatism aberration of the anamorphic lens.

[0033] 3. The ultra-wide-angle and large-aperture anamorphic lens provided by the present invention adopts an internal focus design, and the first lens of the thirteen lenses arranged in sequence from the object side to the image side is used as a front fixed group, the second lens to the sixth lens are used as an internal focus group, and the seventh lens to the thirteenth lens are used as a rear fixed group. The internal focus group moves inside the lens, so that the lens can focus on different object distances.

[0034] 4. The ultra-wide-angle large aperture anamorphic lens provided by the present invention adopts a compact design that integrates a cylindrical lens and a spherical lens, achieving a large aperture of F2.8 while also achieving a lightweight design; wherein the lens length is less than 130 mm, the front end of the lens can match a universal filter with an outer diameter of 67 mm, and the lens mass is less than 750 g. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 It is a schematic cross-sectional view of the X direction of the present invention;

[0037] Figure 2 A schematic cross-sectional view of the Y direction of the present invention;

[0038] Figure 3 This is an optical structure diagram in the X direction of the first embodiment of the present invention;

[0039] Figure 4 This is a Y-direction optical structure diagram of the first embodiment of the present invention;

[0040] Figure 5 This is an optical structure diagram in the X direction of the second embodiment of the present invention;

[0041] Figure 6 This is a Y-direction optical structure diagram of the second embodiment of the present invention;

[0042] Figure 7This is an optical structure diagram in the X direction of the third embodiment of the present invention;

[0043] Figure 8 This is the optical structure diagram in the Y direction of the third embodiment of the present invention.

[0044] Description of reference numerals:

[0045] 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Sixth lens; 7. Seventh lens; 8. Eighth lens; 9. Ninth lens; 10. Tenth lens; 11. Eleventh lens; 12. Twelfth lens; 13. Thirteenth lens; 14. Front fixed group; 15. Inner focusing group; 16. Rear fixed group. DETAILED DESCRIPTION

[0046] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0048] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] Embodiment 1

[0051] like Figure 3-4 is a 24mm focal length half-frame ultra-wide-angle large aperture anamorphic lens, which is composed of thirteen lenses arranged along the optical path from the object side to the image side, namely a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10, an eleventh lens 11, a twelfth lens 12 and a thirteenth lens 13.

[0052] Among them, the first lens 1, the second lens 2, the third lens 3 and the fourth lens 4 are cylindrical lenses, and the second lens 2 and the third lens 3 are bonded together. The fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the ninth lens 9, the tenth lens 10, the eleventh lens 11, the twelfth lens 12 and the thirteenth lens 13 are all spherical lenses.

[0053] Among them, the first lens 1 and the second lens 2 are negative cylindrical lenses, the third lens 3 and the fourth lens 4 are positive power cylindrical lenses, and the fourth lens generatrix is ​​perpendicular to the third lens generatrix. The fifth lens 5, the ninth lens 9, and the tenth lens 10 are all negative power spherical lenses, and the sixth lens 6, the seventh lens 7, the eighth lens 8, the eleventh lens 11, the twelfth lens 12, and the thirteenth lens 13 are all positive power spherical lenses. Among them, the eighth lens 8 and the ninth lens 9 are bonded together, and the tenth lens 10 and the eleventh lens 11 are bonded together.

[0054] The lenses bonded together are regarded as a whole, so the anamorphic lens of this embodiment is composed of 13 lenses in 10 groups.

[0055] There is no specific restriction on the combination method between the second lens 2 and the third lens 3, the eighth lens 8 and the ninth lens 9, and the tenth lens 10 and the eleventh lens 11. In this embodiment, the combination method is bonding. As an alternative implementation method, based on the concept of the present invention, in order to distinguish from the present application, the above combination methods are changed, such as bonding, integrated molding, etc., and the shape of the combined lenses is adaptively changed, which should also be included in the protection scope of the present application.

[0056] There is no specific restriction on the specific values ​​of the actual parameters of each lens. In this embodiment, the focal length of each lens or lens group satisfies the following mathematical relationship:

[0057] 23.6mm<f (1－N) Y<24.4mm;

[0058] 17.6mm<f (1－N) X<19.2mm;

[0059] 1.20<f (1－N) Y / f (1－N) X<1.40;

[0060] 3.50<f 4 Y / f (2－3) X<4.20;

[0061] -3.10<f 1 X / f (1－13) X<-2.70;

[0062] -2.10<f (2－6) Y / f (1－13) Y<-1.60;

[0063] -10.20<f (2－6) X / f (1－13) X<-9.20;

[0064] 2.40<f (7－13) X / f (1－13) X<2.80.

[0065] Due to the non-rotational symmetry of the cylindrical lens, the X direction is defined as the curvature direction of the first lens (e.g. Figure 1 ), the Y direction is another direction that is 90 degrees to the curvature direction of the first lens (as shown Figure 2 The subscript numbers of f represent the numbers of the lenses that make up the anamorphic lens. (M－N) Y represents the combined optical focal length of the Mth lens to the Nth lens (N-M+1) in the Y direction, f (M－N) X represents the combined optical focal length of the M-th lens to the N-th lens (N-M+1) lenses in the X direction; M is a natural number greater than or equal to 1 and less than N.

[0066] The actual parameters of each lens of this embodiment that conform to the above mathematical relationship are listed below:

[0067]

[0068] Among them, the first to fourth lenses are cylindrical lenses, the fourth lens generatrix is ​​perpendicular to the third lens generatrix, and the fifth to thirteenth lenses are spherical lenses.

[0069] Before the anamorphic lens of this embodiment is used, the field of view angle of the lens with a focal length of 24 mm and an aperture of 2.8 is: V (vertical) 36.10°, H (horizontal) 51.62°.

[0070] After adopting the anamorphic lens of this embodiment, the field of view angle of the lens with a focal length of 24 mm and an aperture of 2.8 is: V (vertical) 36.10°, H (horizontal) 68.75°.

[0071] The comparison test shows that the vertical field of view angle remains unchanged, and the horizontal field of view angle deformation ratio is: 68.75 / 51.62=1.332.

[0072] The actual width ratio is in the range of 2.35-2.40, so the distortion ratio is 1.33, which means that the horizontal field of view angle is increased by 33%, thus achieving 1.33X distortion shooting.

[0073] When the anamorphic lens of this embodiment is manufactured, the length of the anamorphic lens itself is less than 130 mm, matching a universal filter with an outer diameter of 67 mm, and the weight is less than 750 g. Both the volume and weight are much smaller than the professional movie anamorphic lenses of the same specifications on the market.

[0074] There is no specific restriction on the material used to make each lens. In this embodiment, each lens is made of optical glass.

[0075] The ultra-wide-angle anamorphic lens of the present application can be designed to be compatible with the bayonet mounts of various brands of cameras on the market according to actual usage requirements, so as to achieve personalized customization and universal coordination.

[0076] Embodiment 2

[0077] like Figure 5 and Figure 6 As shown, this embodiment provides a 24mm focal length half-frame ultra-wide-angle large aperture anamorphic lens, which is different from the first embodiment in that the cemented lens of the original eighth lens 8 and the ninth lens 9 is replaced by a positive spherical lens and a negative spherical lens.

[0078] Embodiment 3

[0079] like Figure 7 and Figure 8 As shown, this embodiment provides a 24mm focal length half-frame ultra-wide-angle large aperture anamorphic lens. The difference from the first embodiment is that the original thirteenth lens 13 is replaced by a positive cemented lens in which a positive spherical lens and a negative spherical lens are bonded together.

[0080] Other examples are based on Example 1, Example 2 and Example 3. If a single positive lens or negative lens is simply split, as long as the focal length distribution of the lens group after the split is within the scope of the original solution, there is no substantial innovation.

[0081] It is not necessary and impossible to list all the embodiments here, and the obvious changes or modifications derived therefrom are still within the protection scope of the invention.

Claims

1. An ultra-wide-angle large aperture anamorphic lens, characterized in that: The invention comprises a cylindrical lens group and a spherical lens group arranged in sequence from the object side to the image side; the cylindrical lens group comprises a first lens (1), a second lens (2), a third lens (3) and a fourth lens (4) arranged in sequence from the object side to the image side, the first lens (1) and the second lens (2) are cylindrical lenses with negative focal lengths, and the third lens (3) and the fourth lens (4) are cylindrical lenses with positive focal lengths; the spherical lens group comprises a fifth lens (5), a sixth lens (6), a seventh lens (7), an eighth lens (8), a ninth lens (9), a tenth lens (10), an eleventh lens (11), a twelfth lens (12) and a thirteenth lens (13) arranged in sequence along the direction of the optical path pointing to the image side, the fifth lens (5), the ninth lens (9) and the tenth lens (10) are all spherical lenses with negative focal lengths, and the sixth lens (6), the seventh lens (7), the eighth lens (8), the eleventh lens (11), the twelfth lens (12) and the thirteenth lens (13) are all spherical lenses with positive focal lengths; The focal power distribution of the lenses constituting the cylindrical lens group and the spherical lens group satisfies the following relationship: 23.6mm<f (1－13) Y<24.4mm; 17.6mm<f (1－13) X<19.2mm; 1.20<f (1－13) Y / f (1－13) X<1.40; 3.50<f4Y / f (2－3) X<4.20; The first lens (1) serves as a front fixed group (14) of the anamorphic lens, the second lens (2) to the sixth lens (6) serve as an inner focusing group (15) of the anamorphic lens, and the seventh lens (7) to the thirteenth lens (13) serve as a rear fixed group (16) of the anamorphic lens; wherein the optical power distribution of the front fixed group (14), the inner focusing group (15) and the rear fixed group (16) satisfies the following relationship: -3.10<f1X / f (1－13) X<-2.70; -2.10<f (2－6) Y / f (1－13) Y<-1.60; -10.20<f (2－6) X / f (1－13) X<-9.20; 2.40<f (7－13) X / f (1－13) X<2.80; The X direction is defined as the curvature direction of the first lens (1), and the Y direction is defined as another direction that is 90 degrees to the curvature direction of the first lens (1); wherein the subscript numerals of f represent the numbers of the lenses constituting the anamorphic lens, and f (M－N) Y represents the combined optical focal length of the Mth lens to the Nth lens (N-M+1) in the Y direction, f (M－N) X represents the combined optical focal length of the M-th lens to the N-th lens (N-M+1) lenses in the X direction; N is a natural number, and M is a natural number greater than or equal to 1 and less than N.

2. The ultra-wide-angle large aperture anamorphic lens according to claim 1, characterized in that: The generatrix of the fourth lens (4) is perpendicular to the generatrix of the third lens (3).

3. The ultra-wide-angle and large-aperture anamorphic lens according to any one of claims 1 to 2, characterized in that: The second lens (2) and the third lens (3) are bonded together.

4. The ultra-wide-angle and large-aperture anamorphic lens according to any one of claims 1 to 2, characterized in that: The eighth lens (8) and the ninth lens (9) are bonded together.

5. The ultra-wide-angle and large-aperture anamorphic lens according to any one of claims 1 to 2, characterized in that: The tenth lens (10) and the eleventh lens (11) are bonded together.

6. The ultra-wide-angle and large-aperture anamorphic lens according to any one of claims 1 to 2, characterized in that: The length of the anamorphic lens is less than 130 mm, and the front end can match a universal filter with a diameter of 67 mm.

7. The ultra-wide-angle and large-aperture anamorphic lens according to any one of claims 1 to 2, characterized in that: The focal length of the anamorphic lens in the Y direction is 24.4 mm, the focal length in the X direction is 18.3 mm, and the aperture is 2.

8.

8. The ultra-wide-angle and large-aperture anamorphic lens according to any one of claims 1 to 2, characterized in that: The mass of the anamorphic lens is less than 750g.

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