A large aperture medium format imaging lens

Abstract

This invention discloses a large-aperture medium format imaging lens, belonging to the field of mirrorless camera lens technology. The lens, arranged sequentially along the direction of incident light, comprises a first lens group G1 with positive optical power, a second lens group G2 with negative optical power, a variable aperture, a third lens group G3 with positive optical power, and a fourth lens group G4 with positive optical power. When focusing on an object moving from infinity to near, the first lens group G1, the third lens group G3, and the fourth lens group G4 remain stationary, while the second lens group G2 moves towards the image plane as the focusing group. The lens is entirely made of spherical glass. By setting up four lens groups with different optical powers (positive-negative-aperture-positive-positive), it achieves precise suppression of lens aberrations, avoiding the use of expensive, large-diameter aspherical lenses and effectively controlling the cost of the imaging lens. Simultaneously, the small size and weight of the focusing group lens reduce the load on the focusing motor, which is beneficial for improving the focusing speed.

Description

Technical Field

[0001] This invention belongs to the field of mirrorless camera lens technology, specifically relating to a large-aperture medium format imaging lens that can be widely used in digital cameras, camcorders, drone cameras and other products. Background Technology

[0002] Aperture and sensor size are important characteristics for evaluating the performance of an imaging lens and determining its suitability for specific applications. The aperture is a blade structure inside the lens that controls the amount of light entering the lens; it is expressed by the f-number, with a smaller f-number indicating a larger aperture. Common large-aperture lenses typically have f-numbers of 1.4, 1.8, 2.0, and 2.8. Large-aperture lenses allow more light in, resulting in brighter images in low light, and they also have a shallow depth of field, making it easier to highlight the subject.

[0003] Image sensor size generally refers to the size of the sensor area within a lens. Common image sensor sizes include APS-C, full-frame, medium format, and large format. The sensor area of ​​a medium format lens is approximately 1.7 times that of a full-frame lens. For example, a full-frame lens typically has a 36×24mm sensor, while a common medium format lens has a 44×33mm or 53×40mm sensor. Compared to full-frame, the larger sensor size of medium format lenses results in superior image quality and dynamic range, but the device size also increases, and lenses with better optical performance are usually required, leading to higher costs.

[0004] This lens combines the core advantages of a large aperture and medium format, boasting features such as extremely shallow depth of field, exceptional low-light image quality, smooth bokeh transitions, detailed skin / material textures, and excellent color gradation. It is particularly suitable for high-value portrait photography, including commercial portraits, fashion shoots, and wedding documentaries, as well as high-value commercial promotional scenarios such as jewelry, food and clothing, showrooms, and guesthouses. Furthermore, it also has significant application value in artistic creation and stage performance photography.

[0005] While large-aperture medium format imaging lenses possess the aforementioned clear technical advantages and significant commercial value, they still face many pressing technical challenges. For example, their excessive size and weight severely impact their portability for everyday carrying. To address this issue, the industry has attempted to solve it through innovative lens structures, such as the solution disclosed in Japanese Patent Application Publication No. 2020-47018. Although this solution achieves a large aperture smaller than F2, the excessive weight of the focusing assembly results in a slow autofocus process.

[0006] For example, Chinese patent CN202411701839.8 discloses a large-aperture medium format wide-angle autofocus lens and image pickup device. This lens employs a fifteen-faceted lens structure with five lens groups: positive-negative-negative-aperture-positive-negative. The second and fourth lens groups are the focusing groups when the lens is in focus. Although this patent application achieves good imaging results, it still suffers from problems such as complex structure, an excessive number of focusing groups, and excessive load on the focusing motor.

[0007] Furthermore, the design of large-aperture medium format lenses faces several general optical challenges. For instance, simply using high-refractive-index lenses to reduce lens size results in a low Abbe number, large beam tilt angles at the edges, and extremely difficult-to-control chromatic aberration, leading to poor edge image quality. Additionally, to achieve high image quality across the entire image field, large-aperture medium format lenses not only need to control the five primary colorless aberrations of Seidal, but also must simultaneously suppress fifth and seventh-order aberrations. This technical requirement significantly increases the design and manufacturing complexity. Failure to suppress higher-order aberrations leads to problems such as center fogging, intersecting star-like patterns at the edges, inconsistent clarity between horizontal and vertical surfaces, and persistent color fringing when the lens is wide open. Currently, the main solution to these technical problems is to use precision large-diameter aspherical lenses; however, these lenses are expensive, significantly increasing lens costs. Summary of the Invention

[0008] (a) Technical problems to be solved

[0009] This invention aims to solve one of the following technical problems existing in the prior art or related technologies:

[0010] Existing large-aperture medium format imaging lenses suffer from problems such as large lens size, heavy focusing group leading to slow focusing speed, high lens cost, and difficulty in controlling aberrations resulting in low image quality.

[0011] (II) Technical Solution

[0012] To solve the above-mentioned technical problems, the present invention provides a large-aperture medium format imaging lens, and the specific technical solution adopted is as follows:

[0013] A large-aperture medium format imaging lens, wherein along the direction of incident light, a first lens group G1 with positive optical power, a second lens group G2 with negative optical power, a variable aperture, a third lens group G3 with positive optical power, and a fourth lens group G4 with positive optical power are arranged sequentially; when the object is brought into focus from infinity to near, the first lens group G1, the third lens group G3, and the fourth lens group G4 remain fixed, while the second lens group G2 moves towards the image plane as the focusing group.

[0014] The first lens group G1 includes five lenses, which are, in order along the incident light direction, the first lens L11, the second lens L12, the third lens L13, the fourth lens L14, and the fifth lens L15; the second lens group G2 includes two lenses, which are, in order along the incident light direction, the sixth lens L21 and the seventh lens L22; the third lens group G3 includes three lenses, which are, in order along the incident light direction, the eighth lens L31, the ninth lens L32, and the tenth lens L33; the fourth lens group G4 includes three lenses, which are, in order along the incident light direction, the eleventh lens L41, the twelfth lens L42, and the thirteenth lens L43.

[0015] The first lens L11, the second lens L12, and the fifth lens L15 are convex positive lenses facing the object side; the third lens L13 and the sixth lens L21 are positive lenses; the fourth lens L14 is a negative lens; the seventh lens L22, the ninth lens L32, and the twelfth lens L42 are biconcave negative lenses; the eighth lens L31, the tenth lens L33, and the eleventh lens L41 are biconvex positive lenses; and the thirteenth lens L43 is a concave negative lens facing the object side; and

[0016] The lens satisfies the following condition:

[0017] 1 < F1 / ENF < 1.4 (1);

[0018] -0.65<F2 / F<-0.4 (2);

[0019] Where F1 is the focal length of the first lens group G1, F2 is the focal length of the second lens group G2, ENF is the entrance pupil distance of the optical system at infinity, and F is the focal distance of the entire optical system at infinity.

[0020] Preferably, the variable aperture STP can be located at any position in the second lens group G2 and the third lens group G3.

[0021] Preferably, the third lens L13 and the fourth lens L14 form a first cemented lens group; the sixth lens L21 and the seventh lens L22 form a second cemented lens group; the eighth lens L31 and the ninth lens L32 form a third cemented lens group; and the eleventh lens L41 and the twelfth lens L42 form a fourth cemented lens group.

[0022] Preferably, the first lens L11 has a refractive index > 1.9 and an Abbe number < 22; the second lens L12 has an Abbe number > 60; and the third lens L13 has an Abbe number > 60.

[0023] Preferably, the focal length of the tenth lens L33 satisfies the following condition:

[0024] 0.4 < F33 / F < 0.6 (3);

[0025] Where F33 is the focal length of the tenth lens L33; F is the focal distance of the entire optical system at infinity.

[0026] Preferably, the distance between the first lens group G1 and the second lens group G2 is 3.5~12.5mm; the distance between the second lens group G2 and the third lens group G3 is 5.5~15mm.

[0027] More preferably, the fourth cemented lens assembly satisfies the following conditions:

[0028] IND_L41-IND_L42>0.4 (4);

[0029] Wherein, IND_L41 is the refractive index of the eleventh lens L41; and IND_L42 is the refractive index of the twelfth lens L42.

[0030] Preferably, the third lens L13 is a plano-convex positive lens convex to the object side; the fourth lens L14 is a plano-concave negative lens concave to the image side; the sixth lens L21 is a biconvex positive lens; and the thirteenth lens L43 is a meniscus negative lens concave to the object side.

[0031] More preferably, the distance between the first lens L11 and the second lens L12 is 0.09~0.11mm; the distance between the second lens L12 and the third lens L13 is 0.63~0.65mm; the distance between the fourth lens L14 and the fifth lens L15 is 2.14~2.16mm; the distance between the ninth lens L32 and the tenth lens L33 is 2.44~2.46mm; the distance between the third lens group G3 and the fourth lens group G4 is 18.78~18.80mm; and the distance between the twelfth lens L42 and the thirteenth lens L43 is 10.77~10.79mm.

[0032] The first lens L11 has a refractive index range of 1.94–1.95 and an Abbe number range of 17.97–17.99; the second lens L12 has a refractive index range of 1.59–1.60 and an Abbe number range of 68.3–68.4; the third lens L13 has a refractive index range of 1.56–1.57 and an Abbe number range of 71.29–71.31; the fourth lens L14 has a refractive index range of 1.84–1.85 and an Abbe number range of 23.77–23.79; the fifth lens L15 has a refractive index range of 1.88–1.89 and an Abbe number range of 40.84–40.86; the sixth lens L21 has a refractive index range of 1.84–1.85 and an Abbe number range of 23.77–23.79; and the seventh lens L22 has a refractive index range of 1.83–1.84. The refractive index of the eighth lens L31 ranges from 1.59 to 1.60, and the Abbe number ranges from 68.33 to 68.35; the refractive index of the ninth lens L32 ranges from 1.74 to 1.75, and the Abbe number ranges from 27.75 to 27.77; the refractive index of the tenth lens L33 ranges from 1.61 to 1.62, and the Abbe number ranges from 63.38 to 63.40; the refractive index of the eleventh lens L41 ranges from 2.00 to 2.01, and the Abbe number ranges from 25.45 to 25.47; the refractive index of the twelfth lens L42 ranges from 1.46 to 1.48, and the Abbe number ranges from 66.87 to 66.89; the refractive index of the thirteenth lens L43 ranges from 1.64 to 1.65, and the Abbe number ranges from 33.83 to 33.85.

[0033] Preferably, the imaging lens has a focal distance of 100~108mm, a half-field angle of view of 14°~15°, and an aperture size of Fno of 1.8~1.9.

[0034] Another object of the present invention is to provide an imaging device comprising any of the above-mentioned large-aperture medium format imaging lenses. This imaging device can be a digital camera, a camcorder, a drone camera, or other existing known imaging devices.

[0035] (III) Beneficial Effects

[0036] Compared with the prior art, the beneficial effects obtained by the present invention are as follows:

[0037] I. All lenses disclosed herein are made of spherical glass. By setting up four different lens groups with different optical powers of "positive-negative-aperture-positive-positive", the lens aberrations can be precisely suppressed, avoiding the use of expensive precision large-diameter aspherical lenses and effectively controlling the cost of imaging lenses.

[0038] II. The lens disclosed herein employs a four-lens-group, thirteen-lens structure. By rationally configuring the number of lenses and lens parameters, it achieves high image quality across all scenarios with a large aperture (F-number less than 2.0) for medium format applications, using a relatively small number of lens elements. At commonly used shooting distances, the MTF50 at the center of the image exceeds 120 line pairs, achieving excellent image quality under medium format conditions with a large aperture, reaching the level of top-tier professional lenses.

[0039] Third, the lens disclosed herein places the aperture stop between the second and third lens groups, and uses the second lens group, consisting of only two lenses, as the focusing moving lens group (i.e., the focusing group). The lenses used are small in size and light in weight, which can effectively reduce the load on the motor during focusing and improve the focusing speed of the lens. At the same time, the focusing group is placed in front of the aperture stop, which effectively compresses the aperture stop diameter, thereby facilitating the miniaturization and weight reduction of the overall lens and improving portability in daily use. Attached Figure Description

[0040] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0041] Figure 1 This is a schematic diagram of the imaging lens in Embodiment 1 of the present invention.

[0042] In the diagram: G1, first lens group; G2, second lens group; G3, third lens group; G4, fourth lens group; L11, first lens; L12, second lens; L13, third lens; L14, fourth lens; L15, fifth lens; L21, sixth lens; L22, seventh lens; STP, aperture stop; L31, eighth lens; L32, ninth lens; L33, tenth lens; L41, eleventh lens; L42, twelfth lens; L43, thirteenth lens; IMG, photosensor and its protective lens.

[0043] Figure 2 The spherical aberration, field curvature aberration, and distortion aberration of the imaging lens in Embodiment 1 of the present invention at infinity and an object distance of 900mm are shown.

[0044] Figure 3 This is a graph of the MTF (modulation transfer function) of the imaging lens in Embodiment 1 of the present invention.

[0045] In the figure: the horizontal axis represents spatial frequency (line pairs / mm), and the vertical axis represents the percentage of image quality that closely approximates the real object. Detailed Implementation

[0046] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented by a variety of different embodiments as defined and covered by the claims.

[0047] In the following description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer" and "vertical" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0048] In the following description of the present invention, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0049] Furthermore, in the following description of the present invention, unless otherwise stated, "multiple", "multiple groups", and "multiple roots" mean two or more.

[0050] In the following examples, all the transmission lenses used are spherical lenses made of glass.

[0051] Example 1

[0052] This embodiment provides a large-aperture medium format imaging lens, the structural schematic of which is shown below. Figure 1 As shown, the lens has a first lens group G1 with positive optical power, a second lens group G2 with negative optical power, a variable aperture STP, a third lens group G3 with positive optical power, and a fourth lens group G4 with positive optical power arranged sequentially along the incident light ray. The variable aperture STP can be positioned anywhere between the second lens group G2 and the third lens group G3. When focusing on an object moving from infinity to near, the first lens group G1, the third lens group G3, and the fourth lens group G4 remain stationary, while the second lens group G2 moves towards the image plane as the focusing group.

[0053] The first lens group G1 has five lenses arranged sequentially along the incident light ray: lens L11, lens L12, lens L13, lens L14, and lens L15. Adjacent surfaces of lens L13 and lens L14 are cemented together to form a first cemented lens group. The second lens group G2 has two lenses arranged sequentially along the incident light ray: lens L21 and lens L22, which together form a second cemented lens group. The third lens group G3 has eight lenses arranged sequentially along the incident light ray: lens L31, lens L32, and lens L33, with lens L31 and lens L32 forming a third cemented lens group. The fourth lens group G4 has eleventh lenses arranged sequentially along the incident light ray: lens L41, lens L42, and lens L43, with lens L41 and lens L42 forming a fourth cemented lens group. Thus, the lens forms a “positive-negative-variable stop-positive-positive” optical system consisting of thirteen lenses in four lens groups.

[0054] Specifically, the first lens L11, the second lens L12, and the fifth lens L15 are convex positive lenses facing the object side; the third lens L13 is a plano-convex positive lens facing the object side; the fourth lens L4 is a plano-concave negative lens facing the image side; the sixth lens L21, the eighth lens L31, the tenth lens L33, and the eleventh lens L41 are biconvex positive lenses; the seventh lens L22, the ninth lens L32, and the twelfth lens L42 are biconcave negative lenses; and the thirteenth lens L43 is a meniscus negative lens facing the object side.

[0055] Furthermore, the optical system constituted by the aforementioned lenses also satisfies the following condition:

[0056] 1 < F1 / ENF < 1.4 (1);

[0057] -0.65<F2 / F<-0.4 (2);

[0058] 0.4 < F33 / F < 0.6 (3);

[0059] IND_L41-IND_L42>0.4 (4);

[0060] Where F1 is the focal length of the first lens group G1, F2 is the focal length of the second lens group G2, ENF is the entrance pupil distance of the optical system at infinity, F is the focal distance of the entire optical system at infinity, F33 is the focal length of the tenth lens L33, IND_L41 is the refractive index of the eleventh lens L41, and IND_L42 is the refractive index of the twelfth lens L42.

[0061] The design concept and principle behind the lens parameters needing to meet the above conditions is as follows:

[0062] When the lens parameters exceed the upper limit of condition (1), the front group of the lens has insufficient converging power, the front and rear lenses of the aperture stop need to withstand a larger beam diameter, and the overall length of the optical system will be forced to lengthen, which is not conducive to reducing the size of the lens; at the same time, the entrance pupil will drift along the optical axis into the lens (i.e., the sensor direction), and the pupil distortion will increase. When the lens parameters are lower than the lower limit of condition (1), the higher-order spherical aberration on the axis will increase dramatically; the incident angle of the principal ray will increase sharply, and coma, astigmatism and distortion will also deteriorate at the same time, and the overall imaging quality of the optical system will decrease sharply.

[0063] When the lens parameters exceed the upper limit of conditional equation (2), the focusing travel will increase significantly or the closest focusing distance will be lost, and the focusing sensitivity will be insufficient, which is not conducive to fast focusing. When the lens parameters are below the lower limit of conditional equation (2), the processing tolerance sensitivity is too high, and small adjustments during the focusing process will cause the focus to move a long distance, which greatly increases the difficulty of focusing. At the same time, the processing accuracy requirements of the focusing mechanism are extremely high, which leads to a significant increase in lens cost.

[0064] When the lens parameters exceed the upper limit of condition (3), it is not conducive to the miniaturization of the lens, and the rear element of the lens will bear too much pressure to correct aberrations, making it difficult to balance aberrations. When the lens parameters are lower than the lower limit of condition (3), the optical system will have difficulty guaranteeing the image quality at the lens edges.

[0065] The setting of condition (4) is mainly used to help the lens's optical system suppress stray light and eliminate advanced spherical aberration. When the lens parameters exceed the range defined by condition (4), the amplitude of advanced spherical aberration in the optical system will increase, and stray light will become severe.

[0066] The specific parameters of the lens structure data in this embodiment are as follows:

[0067] Focal distance: 107mm; Aperture: Fno: 1.83; Half field of view ω: 14.4°

[0068]

[0069] The focus data for the above lenses is as follows:

[0070]

[0071] Where: R (mm) is the radius of curvature of each surface; D (mm) is the thickness of each lens and the lens spacing; Nd is the refractive index of each glass along the d-line; Vd is the Abbe number of the glass.

[0072] In this embodiment, the imaging lens exhibits spherical aberration, field curvature aberration, and distortion aberration at infinity and an object distance of 900mm, as follows: Figure 2 As shown. Meanwhile, the MTF (modulation transfer function) curve of this imaging lens is shown in the figure. Figure 3 As shown. From Figure 2 It can be seen that this lens effectively controls the main aberrations under medium format, large aperture application conditions. From Figure 3 It is known that the optical system constructed by this lens can ensure that the MTF50 at the center of the lens image is higher than 120 line pairs at a normal shooting distance. That is, when the image contrast is reduced by 50%, at least 120 black and white line pairs can be distinguished within a pixel radius of 11mm. This shows that the lens has extremely strong detail resolution and reproduction capabilities, reaching the level of top professional lenses.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A large-aperture medium format imaging lens, characterized in that, The lens is arranged along the direction of incident light with a first lens group (G1) of positive optical power, a second lens group (G2) of negative optical power, a variable aperture, a third lens group (G3) of positive optical power, and a fourth lens group (G4) of positive optical power. When the object is brought into focus from infinity to near, the first lens group (G1), the third lens group (G3), and the fourth lens group (G4) remain fixed, while the second lens group (G2) moves towards the image plane as the focusing group. The first lens group (G1) comprises five lenses, which are, in order along the direction of incident light, the first lens (L11), the second lens (L12), the third lens (L13), the fourth lens (L14), and the fifth lens (L15); the second lens group (G2) comprises two lenses, which are, in order along the direction of incident light, the sixth lens (L21) and the seventh lens (L22); the third lens group (G3) comprises three lenses, which are, in order along the direction of incident light, the eighth lens (L31), the ninth lens (L32), and the tenth lens (L33); and the fourth lens group (G4) comprises three lenses, which are, in order along the direction of incident light, the eleventh lens (L41), the twelfth lens (L42), and the thirteenth lens (L43). The first lens (L11), the second lens (L12), and the fifth lens (L15) are convex positive lenses facing the object side; the third lens (L13) and the sixth lens (L21) are positive lenses; the fourth lens (L14) is a negative lens; the seventh lens (L22), the ninth lens (L32), and the twelfth lens (L42) are biconcave negative lenses; the eighth lens (L31), the tenth lens (L33), and the eleventh lens (L41) are biconvex positive lenses; and the thirteenth lens (L43) is a concave negative lens facing the object side; and The lens satisfies the following condition: 1 < F1 / ENF < 1.4 (1); -0.65<F2 / F<-0.4(2; Where F1 is the focal length of the first lens group (G1), F2 is the focal length of the second lens group (G2), ENF is the entrance pupil distance of the optical system at infinity, and F is the focal distance of the entire optical system at infinity.

2. The large aperture medium format imaging lens according to claim 1, characterized in that, The third lens (L13) and the fourth lens (L14) form the first cemented lens group; the sixth lens (L21) and the seventh lens (L22) form the second cemented lens group; the eighth lens (L31) and the ninth lens (L32) form the third cemented lens group; and the eleventh lens (L41) and the twelfth lens (L42) form the fourth cemented lens group.

3. The large-aperture medium format imaging lens according to claim 1, characterized in that, The first lens (L11) has a refractive index > 1.9 and an Abbe number < 22; the second lens (L12) has an Abbe number > 60; and the third lens (L13) has an Abbe number > 60.

4. The large aperture medium format imaging lens according to claim 1, characterized in that, The focal length of the tenth lens (L33) satisfies the following condition: 0.4 < F33 / F < 0.6 (3); Where F33 is the focal length of the tenth lens (L33); F is the focal distance of the entire optical system at infinity.

5. The large aperture medium format imaging lens according to claim 1, characterized in that, The distance between the first lens group (G1) and the second lens group (G2) is 3.5~12.5mm; the distance between the second lens group (G2) and the third lens group (G3) is 5.5~15mm.

6. The large aperture medium format imaging lens according to claim 2, characterized in that, The fourth cemented lens assembly satisfies the following conditions: IND_L41-IND_L42>0.4 (4); Wherein, IND_L41 is the refractive index of the eleventh lens (L41); IND_L42 is the refractive index of the twelfth lens (L42).

7. The large aperture medium format imaging lens according to claim 2, characterized in that, The third lens (L13) is a plano-convex positive lens convex to the object side; the fourth lens (L14) is a plano-concave negative lens concave to the image side; the sixth lens (L21) is a biconvex positive lens; and the thirteenth lens (L43) is a meniscus negative lens concave to the object side.

8. The large aperture medium format imaging lens according to claim 7, characterized in that, The spacing between the first lens (L11) and the second lens (L12) is 0.09~0.11mm; the spacing between the second lens (L12) and the third lens (L13) is 0.63~0.65mm; the spacing between the fourth lens (L14) and the fifth lens (L15) is 2.14~2.16mm; the spacing between the ninth lens (L32) and the tenth lens (L33) is 2.44~2.46mm; the spacing between the third lens group (G3) and the fourth lens group (G4) is 18.78~18.80mm; and the spacing between the twelfth lens (L42) and the thirteenth lens (L43) is 10.77~10.79mm. The first lens (L11) has a refractive index range of 1.94~1.95 and an Abbe number range of 17.97~17.99; the second lens (L12) has a refractive index range of 1.59~1.60 and an Abbe number range of 68.3~68.4; the third lens (L13) has a refractive index range of 1.56~1.57 and an Abbe number range of 71.29~71.31; the fourth lens (L14) has a refractive index range of... The refractive index ranges from 1.84 to 1.85, and the Abbe number ranges from 23.77 to 23.79; the refractive index range of the fifth lens (L15) is 1.88 to 1.89, and the Abbe number ranges from 40.84 to 40.86; the refractive index range of the sixth lens (L21) is 1.84 to 1.85, and the Abbe number ranges from 23.77 to 23.79; the refractive index range of the seventh lens (L22) is 1.83 to 1.

85.

4. The Abbe number range is 42.72~42.74; the refractive index range of the eighth lens (L31) is 1.59~1.60, and the Abbe number range is 68.33~68.35; the refractive index range of the ninth lens (L32) is 1.74~1.75, and the Abbe number range is 27.75~27.77; the refractive index range of the tenth lens (L33) is 1.61~1.62, and the Abbe number range is 63. The refractive index of the eleventh lens (L41) ranges from 2.00 to 2.01, and the Abbe number ranges from 25.45 to 25.47; the refractive index of the twelfth lens (L42) ranges from 1.46 to 1.48, and the Abbe number ranges from 66.87 to 66.89; the refractive index of the thirteenth lens (L43) ranges from 1.64 to 1.65, and the Abbe number ranges from 33.83 to 33.

85.

9. The large aperture medium format imaging lens according to claim 1, characterized in that, The imaging lens has a focal distance of 100~108mm, a half-field angle of view of 14°~15°, and an aperture size of Fno of 1.8~1.

9.

10. An imaging device, characterized in that, The medium format imaging lens containing any one of claims 1-9.

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