Medium telephoto full-frame lens

Abstract

A medium-telephoto full-frame lens comprising a first lens group (G1), a second lens group (G2), a third lens group (G3), and a fourth lens group (G4) arranged sequentially along the optical axis from the object side to the image side; wherein the combined focal lengths of all lens groups satisfy the following condition expression: 1.5 < f ( G 1 ) / f < 3.3 ; 0.7 < f ( G 2 − G 4 ) / f < 1.5 ; − 1 < f ( G 3 ) / f ( G 2 − G 4 ) < − 0.5 ; where f(G1) is the combined focal length of the first lens group (G1), f(G2-G4) is the combined focal length of the second lens group (G2), the third lens group (G3) and the fourth lens group (G4), f(G3) is the combined focal length of the third lens group (G3) and f is the combined focal length of all lens groups.

Description

Technical area

[0001] The present invention relates to the technical field of optical lenses and, in particular, to a medium telephoto full-frame lens. Background technology

[0002] In recent years, however, the multifunctionality of mobile phones has replaced the daily photography of card cameras. But for photography enthusiasts with higher photography demands, mirrorless cameras can experience the perfect photography experience. Mirrorless camera lenses offer the advantages of small size, light weight, easy portability, a larger image area, and a larger aperture, and can achieve a better background blur effect.

[0003] Existing medium-telephoto full-frame lenses suffer from various aberrations and low-resolution issues when imaging some wavebands. Description of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the disadvantages of various aberrations and low resolution in imaging some wavebands by medium-telephoto full-frame lenses in the prior art and thereby to provide a medium-telephoto full-frame lens.

[0005] In order to solve the above-mentioned technical problems, the technical solution of the present invention is as follows: A medium-telephoto full-frame lens comprises a first lens group, a second lens group, a third lens group, and a fourth lens group arranged sequentially along the optical axis from the object side to the image side; the combined focal lengths of all lens groups satisfy the following conditional expression: 1.5 <f(G1) / f<3,3; 0.7 <f(G2−G4) / f<1,5; −1 <f(G3) / f(G2−G4)<−0,5; where f(G1) is the combined focal length of the first lens group, - is the combined focal length of the second lens group, the third lens group and the fourth lens group, f(G3) is the combined focal length of the third lens group and f is the combined focal length of all lens groups.

[0006] Furthermore, a diaphragm is provided between the first lens group and the second lens group, and the third lens group can move along the direction of the optical axis to achieve focusing.

[0007] Further, the first lens group comprises a first lens, a second lens, a third lens and a fourth lens arranged sequentially along the optical axis from the object side to the image side; wherein the first lens is a meniscus lens with a positive focal length and a convex surface facing the object surface; wherein the second lens is a meniscus lens with a positive diopter value and a convex surface facing the object surface; wherein the third lens is a meniscus lens with a positive diopter value and a convex surface facing the object surface; wherein the fourth lens is a meniscus lens with a negative diopter value and a convex surface facing the object surface.

[0008] The side surfaces where the third lens and the fourth lens meet are cemented together.

[0009] Furthermore, the second lens group comprises a fifth lens; wherein the fifth lens is a meniscus lens with a positive diopter value and a convex surface facing the object surface.

[0010] Furthermore, the third lens group comprises a sixth lens; the sixth lens being a meniscus lens with a negative diopter value and a convex surface facing the object surface.

[0011] Further, the fourth lens group comprises a seventh lens, 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; wherein the seventh lens is a meniscus lens with a negative diopter value and a convex surface facing the object surface; wherein the eighth lens is a meniscus lens with a positive diopter value and a convex surface facing the object surface; wherein the ninth lens is a biconcave lens with a negative diopter value; wherein the tenth lens is a biconvex lens with a positive diopter value; wherein the eleventh lens is a biconvex lens with a positive diopter value; the twelfth lens being a biconcave lens with a negative diopter value; wherein the thirteenth lens is a meniscus lens with a positive diopter value and a convex surface facing the image plane; where the fourteenth lens is a biconcave lens with a negative diopter value.

[0012] Wherein the side surfaces where the seventh lens and the eighth lens meet are cemented together, the side surfaces where the ninth lens and the tenth lens meet are cemented together, the side surfaces where the eleventh lens and the twelfth lens meet are cemented together, and the side surfaces where the thirteenth lens and the fourteenth lens meet are cemented together.

[0013] Furthermore, all of the lenses of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, and the fourteenth lens have a spherical surface on the object side surface facing the object side and on the image side surface facing the image side; and the object side surface of the thirteenth lens facing the object side is an aspherical surface, and the image side surface of the thirteenth lens facing the image side is a spherical surface.

[0014] Furthermore, the aperture of the medium telephoto full-frame lens is 1-1.6 and the focal length of the medium telephoto full-frame lens is 70-90 mm.

[0015] Furthermore, the total optical length of the medium telephoto full-frame lens does not exceed 115 mm.

[0016] The advantage of the medium-telephoto full-frame lens provided by the present invention is that it corrects various aberrations in each waveband so that both the center and peripheral fields of view have sufficient resolution, and that it has the advantages of a simple structure, a small size, and a large aperture, and can achieve high-resolution imaging of objects from infinity to short distances. Brief description of the drawings

[0017] In order to more clearly illustrate the technical solutions in the specific embodiments or prior art of the present invention, the accompanying drawings are briefly presented below. These drawings must be used in describing the specific embodiments or prior art. It is obvious that the accompanying drawings in the following description illustrate some embodiments of the present invention, and that general technical personnel in the field, provided they do not perform creative work, can obtain other drawings based on the accompanying drawings. Fig. 1 is a schematic cross-sectional structural diagram of a medium telephoto full-frame lens in an embodiment of the present invention; Fig.2 is a field curvature distortion diagram of a medium telephoto full-frame lens in an embodiment of the present invention.

[0018] In the figures: G1, first lens group; G2, second lens group; G3, third lens group; G4, fourth lens group; 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, fourteenth lens. Description of the preferred embodiments

[0019] In the following, the technical solution of the present invention will be described clearly and completely in conjunction with the accompanying drawings. Obviously, the description of the embodiments represents only a part of the embodiments of the present invention and not all of them. Based on the embodiments of the present invention, all other embodiments that general technical personnel in this field can obtain without creative effort fall within the scope of the present invention.

[0020] When describing the embodiment of the present invention, it is necessary to point out that an azimuth or positional relationship referring to terms such as "central," "top," "bottom," "left," "right," "vertical," "horizontal," "inside," "outside," and the like, has the azimuth or positional relationship based on the drawing. They are intended to facilitate and simplify the description of the present invention, rather than indicating or implying that the said device or component must have a particular orientation, be constructed, and operate in a particular orientation. Furthermore, the terms "first," "second," and "third" are used only for discriminatory purposes and should not be understood to indicate a relative meaning.

[0021] As in the Fig.As shown in Figures 1 to 2, a medium-telephoto full-frame lens comprises a first lens group G1, a second lens group G2, a third lens group G3, and a fourth lens group G4, arranged sequentially along the optical axis from the object side to the image side. The combined focal lengths of all lens groups satisfy the following conditional expression: 1.5 <f(G1) / f<3,3; 0.7 <f(G2−G4) / f<1,5; −1 <f(G3) / f(G2−G4)<−0,5;; where f(G1) is the combined focal length of the first lens group G1, f(G2-G4) is the combined focal length of the second lens group G2, the third lens group G3 and the fourth lens group G4, f(G3) is the combined focal length of the third lens group G3 and f is the combined focal length of all lens groups.

[0022] In the present embodiment, the first lens group G1 comprises a first lens 1, a second lens 2, a third lens 3, and a fourth lens 4, which are arranged sequentially along the optical axis from the object side to the image side. The first lens 1 is a meniscus lens with a positive focal length and a convex surface facing the object surface; the second lens 2 is a meniscus lens with a positive diopter value and a convex surface facing the object surface; the third lens 3 is a meniscus lens with a positive diopter value and a convex surface facing the object surface; and the fourth lens 4 is a meniscus lens with a negative diopter value and a convex surface facing the object surface; The second lens group G2 comprises a fifth lens 5;The fifth lens 5 is a meniscus lens with a positive diopter value and a convex surface facing the object surface. The third lens group G3 comprises a sixth lens 6; the sixth lens 6 is a meniscus lens with a negative diopter value and a convex surface facing the object surface; an eighth lens 8, a ninth lens 9, a tenth lens 10, an eleventh lens 11, a twelfth lens 12, a thirteenth lens 13, and a fourteenth lens 14, which are arranged sequentially along the optical axis from the object side to the image side; the seventh lens 7 is a meniscus lens with a negative diopter value and a convex surface facing the object surface; the eighth lens 8 is a meniscus lens with a positive diopter value and a convex surface facing the object surface; the ninth lens 9 is a biconcave lens with a negative diopter value. the tenth lens 10 is a biconvex lens with a positive diopter value;The eleventh lens 11 is a biconvex lens with a positive diopter value; the twelfth lens 12 is a biconcave lens with a negative diopter value; the thirteenth lens 13 is a meniscus lens with a positive diopter value and a convex surface facing the image plane; and the fourteenth lens 14 is a biconcave lens with a negative diopter value.

[0023] Wherein, the side surfaces where the third lens 3 and the fourth lens 4 meet are cemented together, the side surfaces where the seventh lens 7 and the eighth lens 8 meet are cemented together, the side surfaces where the ninth lens 9 and the tenth lens 10 meet are cemented together, the side surfaces where the eleventh lens 11 and the twelfth lens 12 meet are cemented together, and the side surfaces where the thirteenth lens and the fourteenth lens 14 meet are cemented together. The cemented lens combination can effectively correct chromatic aberration, making the colors of the shot more realistic.

[0024] In the present embodiment, a diaphragm is provided between the first lens group G1 and the second lens group G2, and the third lens group G3 can move along the optical axis direction to achieve focusing. The third lens group G3 uses only a single lens for the focusing function, making the focusing process easier and simpler.

[0025] In the present embodiment, all of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, 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 fourteenth lens 14 have spherical surfaces on the object side surface and on the image side surface; and the object side surface of the thirteenth lens 13 facing the object side is an aspherical surface, and the image side surface of the thirteenth lens 13 facing the image side is a spherical surface. Such an arrangement can effectively correct aberrations such as spherical aberration and field curvature and reduce the overall weight of the lens.

[0026] In the present embodiment, the aperture of the medium-telephoto full-frame lens is 1-1.6, and the focal length of the medium-telephoto full-frame lens is 70-90 mm. In the present embodiment, the total optical length of the medium-telephoto full-frame lens does not exceed 115 mm.

[0027] The relevant parameters of each lens are listed in Table 1 below: Table 1 lens Surface shape Radius R (mm) Thickness D (mm) Refractive index Nd Abbe number Vd First lens Spherical surface 64,708 4,80 1,928 18,38 Spherical surface 146,295 1,02 Second lens Spherical surface 67,274 6,87 1,529 66,58 Spherical surface 88,138 0,21 Third lens Spherical surface 36,718 7,72 1,563 69,66 Fourth lens Spherical surface 157,150 1,47 1,901 15,98 Spherical surface 35,489 12,53 aperture Spherical surface Infinite 1,34 Fifth lens Spherical surface 42,704 3,79 1,831 35,66 Spherical surface 170,162 2,87 Sixth lens Spherical surface 676,825 0,66 1,558 38,98 Spherical surface 32,242 11,30 Seventh lens Spherical surface 79,484 0,85 1,859 20,32 Eighth lens Spherical surface 19,923 5,99 1,533 49,47 Spherical surface 65,393 3,62 Ninth lens Spherical surface -43,130 1,09 1,617 43,88 Tenth lens Spherical surface 60,495 5,81 2,043 14,32 Spherical surface -59,925 0,21 Eleventh lens Spherical surface 144,127 6,33 1,804 48,44 Twelfth lens Spherical surface -34,702 1,00 1,608 32,52 Spherical surface 137,916 5,06 Thirteenth lens Aspherical surface -775,521 3,82 1,864 32,71 Fourteenth lens Spherical surface -37,772 1,15 1,654 19,06 Spherical surface 672,557 3,34 Spherical surface Infinite 2,71 1,517 64,20 Spherical surface Infinite 14.85

[0028] The aspherical coefficient of the thirteenth lens is shown in Table 2 below: Table 2 Thirteenth lens Aspherical surface K 0 A4 -4.19409E-06 A6 -8.09531E-10 A8 5.91892E-12 A10 -2.3495E-14 A12 6.14834E-18 A14 2.40936E-20

[0029] As in Fig. As shown in Figure 1, the sixth lens 6 can focus inwardly between the fifth lens 5 and the seventh lens 7 in the direction of the optical axis. This allows the overall length of the lens to remain constant during focal length adjustment.

[0030] This medium-telephoto full-frame lens corrects various aberrations in each waveband so that both the center and edge fields of view have sufficient resolution. It has the advantages of a simple structure, small size, and large aperture, and can achieve high-resolution imaging of objects from infinity to short distances.

[0031] As from Fig. 2, the field curvature is in the meridional direction (corresponds to T in Fig. 2) and in sagittal direction (corresponds to S in Fig. 2) produced by the medium-telephoto full-frame lens for light is between -0.2 mm and 0.2 mm; the maximum distortion of half-frame lenses is within 10%.

[0032] It should be pointed out that this full-frame mid-telephoto lens adopts an integrated design that enables lens miniaturization while achieving excellent cost-effective optical performance such as high resolution, low breathing, and low distortion, and can be designed to fit the connection of various camera brands on the market according to the actual needs of use, so as to achieve customized customization and universal use.

[0033] Of course, the above-mentioned embodiments serve only as examples for clear explanation and are not intended to limit the embodiments. Other forms of changes or modifications are also possible for general technical personnel in this field based on the above description. An exhaustive list of all embodiments is neither necessary nor possible. The obvious changes or modifications derived therefrom still fall within the scope of the present invention.

Claims

[1] A medium-telephoto full-frame lens comprising a first lens group (G1), a second lens group (G2), a third lens group (G3), and a fourth lens group (G4) arranged sequentially along the optical axis from the object side to the image side; the combined focal lengths of all the lens groups satisfy the following conditional expression: 1.5 <f(G1) / f<3,3; 0.7 <f(G2−G4) / f<1,5; −1 <f(G3) / f(G2−G4)<−0,5; where f(G1) is the combined focal length of the first lens group (G1), f(G2-G4) is the combined focal length of the second lens group (G2), the third lens group (G3) and the fourth lens group (G4), f(G3) is the combined focal length of the third lens group (G3) and f is the combined focal length of all lens groups. [2] Medium telephoto full-frame lens according to claim 1, characterized bythat a diaphragm is provided between the first lens group (G1) and the second lens group (G2) and the third lens group (G3) can move along the direction of the optical axis to achieve focusing. [3] A medium-telephoto full-frame lens according to claim 1, wherein the first lens group (G1) comprises a first lens (1), a second lens (2), a third lens (3) and a fourth lens (4) arranged sequentially along the optical axis from the object side to the image side; wherein the first lens (1) is a meniscus lens with a positive focal length and a convex surface facing the object surface; wherein the second lens (2) is a meniscus lens with a positive diopter value and a convex surface facing the object surface; wherein the third lens (3) is a meniscus lens with a positive diopter value and a convex surface facing the object surface; wherein the fourth lens (4) is a meniscus lens with a negative diopter value and a convex surface facing the object surface; wherein the side surfaces where the third lens (3) and the fourth lens (4) meet are cemented together. [4] A medium-telephoto full-frame lens according to claim 1, wherein the second lens group (G2) comprises a fifth lens (5); wherein the fifth lens (5) is a meniscus lens with a positive diopter value and a convex surface facing the object surface. [5] A medium-telephoto full-frame lens according to claim 1, wherein the third lens group (G3) comprises a sixth lens (6); wherein the sixth lens (6) is a meniscus lens with a negative diopter value and a convex surface facing the object surface. [6] A medium-telephoto full-frame lens according to claim 3, wherein the fourth lens group (G4) comprises a seventh lens (7), an eighth lens (8), a ninth lens (9), a tenth lens (10), an eleventh lens (11), a twelfth lens (12), a thirteenth lens (13) and a fourteenth lens (14) arranged sequentially along the optical axis from the object side to the image side; wherein the seventh lens (7) is a meniscus lens with a negative diopter value and a convex surface facing the object surface; wherein the eighth lens (8) is a meniscus lens with a positive diopter value and a convex surface facing the object surface; wherein the ninth lens (9) is a biconcave lens with a negative diopter value; wherein the tenth lens (10) is a biconvex lens with a positive diopter value; wherein the eleventh lens (11) is a biconvex lens with a positive diopter value; wherein the twelfth lens (12) is a biconcave lens with a negative diopter value; wherein the thirteenth lens (13) is a meniscus lens with a positive diopter value and a convex surface facing the image plane; wherein the fourteenth lens (14) is a biconcave lens with a negative diopter value; wherein the side surfaces at which the seventh lens (7) and the eighth lens (8) meet are cemented together, the side surfaces at which the ninth lens (9) and the tenth lens (10) meet are cemented together, the side surfaces at which the eleventh lens (11) and the twelfth lens (12) meet are cemented together, and the side surfaces at which the thirteenth lens and the fourteenth lens (14) meet are cemented together. [7] Medium telephoto full-frame lens according to claim 6, characterized bythat all lenses of the first lens (1), the second lens (2), the third lens (3), the fourth lens (4), 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 fourteenth lens (14) have a spherical surface on the object side surface facing the object side and on the image side surface facing the image side; and that the object side surface of the thirteenth lens (13) facing the object side is an aspherical surface and the image side surface of the thirteenth lens (13) facing the image side is a spherical surface. [8] Medium telephoto full-frame lens according to claim 1, characterized by that the aperture of the medium telephoto full-frame lens is 1-1.6 and the focal length of the medium telephoto full-frame lens is 70-90 mm. [9] Medium telephoto full-frame lens according to claim 1, characterized bythat the total optical length of the medium telephoto full-frame lens does not exceed 115 mm.

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