An ultra-large aperture single-lens reflex full-frame lens

Abstract

An ultra-large aperture single-lens reflex full-frame lens belongs to the technical field of cinematographic equipment. Along the light incident direction, the lens is successively provided with a first lens group with a negative diopter, a diaphragm, and a second lens group with a positive diopter; the diaphragm is located at any position in the second lens group; when the object is focused from infinity to a short distance, the first lens group remains stationary, and the second lens group, as the focusing group, axially moves from the image plane side to the object side direction; and the lens satisfies the conditional expressions: 2.5 ≤ |F1 / F| ≤ 7; 0.05 ≤ |D12 / F| ≤ 0.2. Compared with the existing large aperture lenses, the ultra-large aperture lens of the present invention has a larger aperture, and the aperture size can reach F0.90 to F1.15. Excellent imaging effects can be achieved from infinity to a short distance, and miniaturization, low cost, and easy mass production are realized, having good practical value.

Description

Technical Field

[0001] The present invention belongs to the technical field of cinematographic equipment, and particularly relates to an ultra-large aperture single-lens reflex full-frame lens. Background Art

[0002] With the progress of intelligent manufacturing technology and the improvement of people's sensory requirements, the requirements for the performance and cost-effectiveness of professional cameras are gradually increasing. Professional cameras, namely single-lens reflex cameras, are fully called single-lens reflex cameras. After light passes through the camera lens and reaches the mirror, it is refracted to the focusing screen to form an image. Through the eyepiece and the pentaprism, the photographer can see the photographed scene in the viewfinder. Compared with digital cameras that can only see the image after conversion processing through the LCD screen or the electronic viewfinder EVF, single-lens reflex cameras can directly see a more real image, so it is more conducive to shooting adjustment and the imaging sensory quality is better.

[0003] Among them, the imaging optical lens is the most important component in the camera. The lens performance directly affects the quality of the captured image, and the best effect of the current lens applicable focal length is achieved through the image conversion of the lens group in the lens. The lens of a single-lens reflex camera can be completely removed and replaced with another lens to obtain different shooting effects.

[0004] At present, there are various single-lens reflex (SLR) camera lenses on the market. Among them, the aperture of the lens is a very important parameter. The aperture is a component used to control the size of the lens aperture, so as to adjust the depth of field, the amount of light entering, increase the shutter speed, capture moving objects, and reduce image blurring caused by jitter. The aperture value is generally represented by F. The larger the F value, the smaller the aperture; the smaller the F value, the larger the aperture. That is to say, the smaller the F value, the higher the lens quality and the more complex its manufacturing process. When the lens is used to shoot close-up pictures, a very small depth of field is required. One way to reduce the depth of field is to increase the aperture, which requires reducing the F value. The F value of the existing lenses on the market is generally above 1.2, which cannot meet the higher requirements of photography. The technical difficulty lies in that if the F value is reduced below 1.2, the large aperture will cause more advanced aberration problems, which will easily lead to a decline in image quality. Aspherical lenses can correct advanced aberrations well, but the price of aspherical lenses is high and the cost is high. Therefore, when reducing the F value, it is also necessary to consider the problem of correcting more advanced aberrations, and at the same time control the manufacturing cost of the lens group, which puts higher design requirements on the structure of the lens group. In addition, most of the existing lenses use the overall movement focusing or front-group focusing method, which is prone to the drooping phenomenon; when the lens is used for video recording, there will also be a serious "breathing effect". The "breathing effect" will cause the viewing angle to change during continuous focusing, affecting the imaging effect; and the optical elements and optical apertures are prone to radial enlargement, and the configuration of the refractive power of the wide-angle optical system is asymmetric before and after, which is prone to lateral chromatic aberration and distortion. Therefore, how to make the large-aperture lens smaller in volume, shorter in focal length, reduce the breathing effect and optical distortion is also a problem that the lens needs to solve. At present, there is no SLR full-frame lens with a short focal length and an ultra-large aperture and high imaging quality in the existing technology. Summary of the Invention

[0005] Aiming at the problems existing in the existing camera lenses, such as poor imaging quality after increasing the aperture and difficult-to-correct aberration problems, the focusing method is prone to the drooping phenomenon, a serious "breathing effect" will occur during video recording, radial enlargement is prone to lateral chromatic aberration and distortion, and the lens group has a high cost and low performance. The present invention provides an ultra-large aperture SLR full-frame lens with an ultra-large aperture, small volume, short lens focal length, solves the problem of long back working distance, will not have the drooping phenomenon, can be adapted to SLR cameras, and can also be adapted to mirrorless cameras. The recorded or captured pictures are clear, the breathing effect is extremely low, and the cost performance is very high; the short focal length ultra-large aperture SLR full-frame lens of the present invention also fills the market gap, raising the technical ability of the domestic lens industry to a new level and meeting the higher usage requirements of the majority of enthusiasts. The specific technical solutions are as follows:

[0006] An ultra-large aperture single-lens reflex full-frame lens is provided with a first lens group with a negative diopter, a diaphragm, and a second lens group with a positive diopter in sequence along the light incident direction; the diaphragm is located at any position in the second lens group; when the object is focused from infinity to a close distance, the first lens group remains stationary, and the second lens group, as the focusing group, axially moves from the image plane side to the object side direction; and the lens satisfies the following conditional expressions:

[0007] 2.5 ≤ |F1 / F| ≤ 7; (1)

[0008] 0.05 ≤ |D12 / F| ≤ 0.2; (2)

[0009] Where: F1 is the focal length of the first lens group; F is the focal length of the entire optical system in the infinity state; D12 is the interval between the first lens group and the second lens group in the infinity state, and the interval is the center distance between the mirror surfaces.

[0010] In the above technical solution, the lens also satisfies the following conditional expressions:

[0011] 1 ≤ |F1 / F2| ≤ 5; (3)

[0012] Where: F1 is the focal length of the first lens group; F2 is the focal length of the second lens group.

[0013] In the above technical solution, the lens also satisfies the following conditional expressions:

[0014] 1 ≤ |F2 / F| ≤ 2.5; (4)

[0015] Where: F2 is the focal length of the second lens group; F is the focal length of the entire optical system in the infinity state.

[0016] In the above technical solution, all the lenses of the first lens group and the second lens group are spherical lenses; the focal length of the second lens group is greater than that of the first lens group.

[0017] In the above technical solution, the focal length of the lens is 34 mm to 37 mm, and the aperture size is F0.90 to F1.15. Preferably, the focal length of the lens is 35 mm, and the aperture size is F1.0.

[0018] In the above technical solution, the lens is applied to digital cameras, video cameras, or used by being adapted to mirrorless cameras.

[0019] In the above technical solution, the first lens group includes four lenses, which are, in order of the light incident direction, a first lens, a second lens, a third lens, and a fourth lens; the first lens is a negative lens convex toward the object side, the second lens is a negative lens convex toward the object side, the third lens is a biconcave negative lens, and the fourth lens is a biconvex positive lens; the second lens group includes nine lenses, which are, in order of the light incident direction, 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; the tenth lens and the eleventh lens are arranged with their surfaces closely attached; the fifth lens is a biconvex positive lens, the sixth lens is a positive lens convex toward the object side, the seventh lens is a negative lens convex toward the object side, the eighth lens is a negative lens convex toward the object side, the ninth lens is a biconvex positive lens, the tenth lens is a biconcave negative lens, the eleventh lens is a biconvex positive lens, the twelfth lens is a biconvex positive lens, and the thirteenth lens is a positive lens convex toward the object side.

[0020] In the above technical solution, the distance between the first lens and the second lens of the first lens group is 5.00 - 7.00 mm, the distance between the second lens and the third lens is 11.00 - 14.00 mm, and the distance between the third lens and the fourth lens is 10.00 - 13.00 mm; the distance is the center distance between the lens surfaces; the refractive index range of the first lens of the first lens group is 1.85 - 1.95, and the Abbe number range is 39 - 41; the refractive index range of the second lens is 1.70 - 1.80, and the Abbe number range is 46 - 48; the refractive index range of the third lens is 1.45 - 1.55, and the Abbe number range is 69 - 71; the refractive index range of the fourth lens is 1.85 - 1.95, and the Abbe number range is 30 - 32;

[0021] The distance between the fifth lens and the sixth lens of the second lens group is 0.00 - 1.00 mm, the distance between the sixth lens and the seventh lens is 7.00 - 9.00 mm, the distance between the seventh lens and the eighth lens is 6.00 - 8.00 mm, the distance between the eighth lens and the ninth lens is 3.00 - 4.00 mm, the distance between the ninth lens and the tenth lens is 4.50 - 7.50 mm, the distance between the tenth lens and the eleventh lens is 0 mm, the distance between the eleventh lens and the twelfth lens is 0.00 - 1.00 mm, and the distance between the twelfth lens and the thirteenth lens is 0.00 - 1.00 mm; the adjustment distance range between the first lens group and the second lens group is 0.5 mm - 5 mm, that is, the adjustment distance range between the fourth lens and the fifth lens is 0.5 mm - 5 mm; the distance is the center distance between the mirror surfaces; the refractive index range of the fifth lens of the second lens group is 1.45 - 1.55, and the Abbe number range is 80 - 82; the refractive index range of the sixth lens is 1.85 - 1.95, and the Abbe number range is 40 - 42; the refractive index range of the seventh lens is 1.60 - 1.70, and the Abbe number range is 33 - 35; the refractive index range of the eighth lens is 1.80 - 1.90, and the Abbe number range is 22 - 24; the refractive index range of the ninth lens is 1.85 - 1.95, and the Abbe number range is 39 - 41; the refractive index range of the tenth lens is 1.80 - 1.90, and the Abbe number range is 22 - 24; the refractive index range of the eleventh lens is 1.45 - 1.55, and the Abbe number range is 80 - 82; the refractive index range of the twelfth lens is 1.85 - 1.95, and the Abbe number range is 39 - 41; the refractive index range of the thirteenth lens is 1.85 - 1.95, and the Abbe number range is 40 - 42.

[0022] In the above technical solution, the first lens group includes 5 lenses, which are, in the order of the light incident direction, the first lens, the second lens, the third lens, the fourth lens, and the fifth lens; the first lens is a negative lens convex toward the object side, the second lens is a negative lens convex toward the object side, the third lens is a biconcave negative lens, the fourth lens is a positive lens convex toward the image side, and the fifth lens is a positive lens convex toward the object side; the second lens group includes 9 lenses, which are, in the order of the light incident direction, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, the thirteenth lens, and the fourteenth lens; the mirror surfaces between the eighth lens and the ninth lens are in close contact, and the mirror surfaces between the eleventh lens and the twelfth lens are in close contact; the sixth lens is a biconvex positive lens, the seventh lens is a negative lens convex toward the object side, the eighth lens is a biconcave negative lens, the ninth lens is a biconvex positive lens, the tenth lens is a positive lens convex toward the image side, the eleventh lens is a negative lens convex toward the object side, the twelfth lens is a biconvex positive lens, the thirteenth lens is a biconvex positive lens, and the fourteenth lens is a positive lens convex toward the object side.

[0023] In the above technical solution, the distance between the first lens and the second lens of the first lens group is 5.50 to 7.50 mm, the distance between the second lens and the third lens is 12.00 to 14.00 mm, the distance between the third lens and the fourth lens is 3.00 to 5.00 mm, and the distance between the fourth lens and the fifth lens is 0 to 1 mm; the distance is the center distance between the lens surfaces; the refractive index range of the first lens of the first lens group is 1.85 to 1.95, and the Abbe number range is 15 to 20; the refractive index range of the second lens is 1.70 to 1.80, and the Abbe number range is 18 to 24; the refractive index range of the third lens is 1.50 to 1.65, and the Abbe number range is 45 to 50; the refractive index range of the fourth lens is 1.95 to 2.05, and the Abbe number range is 22 to 27, and the refractive index range of the fifth lens is 1.90 to 2.00, and the Abbe number range is 17 to 21;

[0024] The distance between the sixth lens and the seventh lens of the second lens group is 9.00 to 13.00 mm, the distance between the seventh lens and the eighth lens is 16.00 to 19.50 mm, the distance between the eighth lens and the ninth lens is 0 mm, the distance between the ninth lens and the tenth lens is 0.00 to 1.00 mm, the distance between the tenth lens and the eleventh lens is 0.00 to 1.00 mm, the distance between the eleventh lens and the twelfth lens is 0 mm, the distance between the twelfth lens and the thirteenth lens is 0.00 to 1.00 mm, and the distance between the thirteenth lens and the fourteenth lens is 0.00 to 1.00 mm; the adjustment distance range between the first lens group and the second lens group is 0.5 mm to 5 mm, that is, the adjustment distance range between the fifth lens and the sixth lens is 0.5 mm to 5 mm; the distance is the center distance between the lens surfaces; the refractive index range of the sixth lens of the second lens group is 1.65 to 1.75, and the Abbe number range is 45 to 50; the refractive index range of the seventh lens is 1.50 to 1.60, and the Abbe number range is 45 to 50; the refractive index range of the eighth lens is 1.75 to 1.85, and the Abbe number range is 20 to 25; the refractive index range of the ninth lens is 1.75 to 1.85, and the Abbe number range is 39 to 46; the refractive index range of the tenth lens is 1.85 to 1.95, and the Abbe number range is 39 to 41; the refractive index range of the eleventh lens is 1.75 to 1.85, and the Abbe number range is 22 to 24; the refractive index range of the twelfth lens is 1.45 to 1.55, and the Abbe number range is 80 to 82; the refractive index range of the thirteenth lens is 1.85 to 1.95, and the Abbe number range is 39 to 41; the refractive index range of the fourteenth lens is 1.85 to 1.95, and the Abbe number range is 40 to 42.

[0025] In the above technical solution, the lens further includes a housing assembly. The first lens group is connected to the housing assembly. The second lens group is a focusing group. The aperture stop is arranged in the second lens group and moves axially with the second lens group.

[0026] The design concept and principle of a super large aperture single - lens reflex full - frame lens of the present invention are as follows:

[0027] In the lens parameter design of the present invention, when exceeding the upper limit of conditional formula (1), the diopter of the first lens group will be very weak, and in this way, the volume is easily miniaturized. However, due to the too - weak diopter of the first lens group, the correction of various aberrations of the second lens group becomes very weak, and it becomes more difficult to achieve high performance. When exceeding the lower limit of conditional formula (1), the diopter of the first lens group becomes very strong. Although it can achieve good aberration correction for the second lens group, due to too much correction, the tolerance sensitivity between groups is too high, the processing requirements are too high, it is very difficult to achieve mass production, the yield rate is too low, and the manufacturing cost is increased.

[0028] In the lens parameter design of the present invention, when exceeding the upper limit of conditional formula (2), the interval between the first lens group and the second lens group is large enough. Although it is easy to solve the space required for focusing movement, the volume of the entire optical system will be very large, and it is difficult to meet the requirement of miniaturization. When exceeding the lower limit of conditional formula (2), although it is easy to achieve miniaturization, due to the too - small movement space of the focusing group, it is very difficult to achieve the close - range focusing function. At the same time, the auxiliary focusing freedom of the second lens group is reduced, and the ability to correct aberrations such as field curvature and spherical aberration is weakened, and the high - performance requirement cannot be achieved.

[0029] In the lens parameter design of the present invention, when exceeding the upper limit of conditional formula (3), the diopter of the first lens group will be very weak, or the diopter of the second lens group will become very strong. In this way, the volume is easily miniaturized. However, due to the too - weak diopter of the first lens group, the correction of various aberrations of the second lens group becomes very weak, and it becomes more difficult to achieve high performance. At the same time, it is very difficult to achieve the wide - angle effect. When exceeding the lower limit of conditional formula (3), the diopter of the second lens group becomes very weak, and the ability to correct aberrations is weakened. Therefore, it is very difficult to achieve the high - performance super large aperture effect.

[0030] In the lens parameter design of the present invention, when exceeding the upper limit of conditional formula (4), the diopter of the second lens group will be weakened. Although it is beneficial to the correction of aberrations, the movement amount of the second lens group as the main focusing group will increase. In this way, the volume of the entire optical system will become very large, and it is very difficult to meet the requirements of super large aperture and small volume. When exceeding the lower limit of conditional formula (4), the light intensity of the second lens group will become very strong. Although the volume can be easily controlled, due to the too - strong diopter, more spherical aberration, coma and other aberrations will be generated, and it is very difficult to ensure high performance.

[0031] A super large aperture single - lens reflex full - frame lens of the present invention has the following beneficial effects compared with the prior art:

[0032] 1. The lens of the present invention is provided with a first lens group and a second lens group. The first lens group is firmly connected to the camera. The second lens group serves as a focusing group and will not droop, resulting in better shooting stability.

[0033] 2. Although the lens of the present invention is provided with several lenses, the lens spacing is compact and the focal length adjustment is short, making the overall length of the lens short, reducing the volume, and effectively improving the front-back symmetry of the refractive power configuration of the optical system, and it is not easy to generate lateral chromatic aberration and distortion.

[0034] 3. All the lenses of the lens of the present invention are spherical lenses. Spherical lenses can effectively reduce the manufacturing cost, improve the cost performance, and be more competitive in the market. Moreover, the design shapes, assembly sequences, spacings, lens parameters, and focusing position designs of several spherical lenses make the lens have better resolution and contrast, and small field curvature. It can achieve an ultra-large aperture F value of 0.90 - 1.15, improve the technical quality of the lens, and can achieve a very good effect of correcting high-order aberrations, comparable to the correction effect of aspherical lenses. Especially for a lens with a focal length of 35mm and an aperture size of F1.0, with excellent performance, it realizes the technology of a short-focal-length ultra-large-aperture single-lens reflex full-frame lens with high imaging quality.

[0035] 4. The designed aperture of the lens of the present invention is arranged in the second lens group and can move back and forth following the second lens group, better adjusting the intensity of light. And the aperture moves synchronously with the second lens group. The adjustment distance range between the first lens group and the second lens group is 0.5 - 5mm, which can effectively reduce the breathing effect during use, enabling the lens to achieve an approximate zero breathing effect during video recording.

[0036] In summary, by optimizing and adjusting the intervals between lenses, the refractive index of the lenses, the Abbe number range, and the focusing position design, the present invention enables the lens to obtain better performance. The aperture size is F0.90 - F1.15, the lens focal length is 34 - 37mm, the lens distortion is small, the MTF of 10 line pairs is greater than 0.9, and the MTF of 30 line pairs is greater than 0.75 under a better object distance. It realizes the technology of a short-focal-length ultra-large-aperture single-lens reflex full-frame lens with high imaging quality, raising the technical ability of the domestic lens industry to a new level, meeting the higher usage requirements of the majority of enthusiasts, having high cost performance, being able to be adapted to single-lens reflex cameras, and can also be adapted to mirrorless cameras, with good practical value.

[0037] Compared with the existing large-aperture lens technology, the lens of the present invention has a larger aperture, with an aperture size of F0.90 - F1.15, and can achieve excellent imaging effects from infinity to close range, and realizes miniaturization, low cost, and easy mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1Schematic diagram of the structure of a super-large aperture single-lens reflex full-frame lens according to Embodiment 1 of the present invention. In the figure: 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.

[0039] Figure 2 MTF (Modulation Transfer Function) curve graph of a super-large aperture single-lens reflex full-frame lens according to Embodiment 1 of the present invention. In the figure: the abscissa is the spatial frequency (line pairs / mm), and the ordinate is the percentage representing the imaging quality approaching the actual object condition.

[0040] Figure 3 Distortion curve graph of a super-large aperture single-lens reflex full-frame lens according to Embodiment 1 of the present invention. In the figure: the abscissa is the image field height (mm), and the ordinate is the percentage of distortion.

[0041] Figure 4 Schematic diagram of the structure of a super-large aperture single-lens reflex full-frame lens according to Embodiment 2 of the present invention. In the figure: 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.

[0042] Figure 5 MTF (Modulation Transfer Function) curve graph of a super-large aperture single-lens reflex full-frame lens according to Embodiment 2 of the present invention. In the figure: the abscissa is the spatial frequency (line pairs / mm), and the ordinate is the percentage representing the imaging quality approaching the actual object condition.

[0043] Figure 6 Distortion curve graph of a super-large aperture single-lens reflex full-frame lens according to Embodiment 2 of the present invention. In the figure: the abscissa is the image field height (mm), and the ordinate is the percentage of distortion. Specific embodiments

[0044] The following further illustrates the present invention in combination with specific implementation cases and appendices Figure 1-6 but the present invention is not limited to these embodiments.

[0045] Embodiment 1

[0046] An ultra-large aperture single-lens reflex full-frame lens is provided with a first lens group with a negative diopter, a diaphragm, and a second lens group with a positive diopter in sequence along the light incident direction; when focusing from infinity to a close distance, the first lens group is fixed and immovable, is a fixed lens group and is connected to the housing assembly; the second lens group serves as a focusing group and axially moves from the image plane side to the object side direction; and the lens satisfies the following conditional expressions:

[0047] 2.5 ≤ |F1 / F| ≤ 7; (1)

[0048] 0.05 ≤ |D12 / F| ≤ 0.2; (2)

[0049] Wherein: F1 is the focal length of the first lens group; F is the focal length of the entire optical system in the infinity state; D12 is the interval between the first lens group and the second lens group in the infinity state, and the interval is the central distance between the lens surfaces.

[0050] In the above technical solution, the lens also satisfies the following conditional expressions:

[0051] 1 ≤ |F1 / F2| ≤ 5; (3)

[0052] Wherein: F1 is the focal length of the first lens group; F2 is the focal length of the second lens group.

[0053] In the above technical solution, the lens also satisfies the following conditional expressions:

[0054] 1 ≤ |F2 / F| ≤ 2.5; (4)

[0055] Wherein: F2 is the focal length of the second lens group; F is the focal length of the entire optical system in the infinity state.

[0056] Such as Figure 1As shown in the figure, the first lens group of this embodiment includes 4 lenses, which are the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 in sequence along the light incident direction; the first lens 1 is a negative lens convex toward the object side, the second lens 2 is a negative lens convex toward the object side, the third lens 3 is a biconcave negative lens, and the fourth lens 4 is a biconvex positive lens. The second lens group includes 9 lenses, which are 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 in sequence along the light incident direction; the tenth lens 10 and the eleventh lens 11 are arranged with their mirror surfaces closely attached; the fifth lens 5 is a biconvex positive lens, the sixth lens 6 is a positive lens convex toward the object side, the seventh lens 7 is a negative lens convex toward the object side, the eighth lens 8 is a negative lens convex toward the object side, the ninth lens 9 is a biconvex positive lens, the tenth lens 10 is a biconcave negative lens, the eleventh lens 11 is a biconvex positive lens, the twelfth lens 12 is a biconvex positive lens, and the thirteenth lens 13 is a positive lens convex toward the object side. The aperture stop is arranged between the seventh lens 7 and the eighth lens 8 of the second lens group and moves axially with the second lens group.

[0057] The specific parameters of the lens structure data of this embodiment are as follows:

[0058] Focal length: 35.41; Aperture size Fno: 1.0500; Half field of view angle: 31.38°;

[0059]

[0060]

[0061] Object distance 330 inf D(8) 0.76 4.56 D(26) 40.14 36.34

[0062] Where: R (mm) is the radius of curvature of each surface; D (mm) is the interval between each lens and the lens thickness; Nd is the refractive index of each glass for the d-line; Vd is the Abbe number of the glass.

[0063] The MTF (Modulation Transfer Function) curve graph of the lens in this embodiment is as Figure 2 shown, and the distortion curve graph is as Figure 3 shown. It can be seen that the performance of the lens in this embodiment is very good, meeting the usage requirements of a short focal length, super large aperture, single-lens reflex full-frame lens with high imaging quality.

[0064] Embodiment 2

[0065] An ultra-large aperture single-lens reflex full-frame lens is provided with a first lens group with a negative diopter, a diaphragm, and a second lens group with a positive diopter in sequence along the light incident direction; when the object is focused from infinity to a close distance, the first lens group is fixed and immovable, is a fixed lens group and is connected to the housing assembly; the second lens group is used as a focusing group and axially moves from the image plane side to the object side direction; and the lens satisfies the following conditional expressions:

[0066] 2.5 ≤ |F1 / F| ≤ 7; (1)

[0067] 0.05 ≤ |D12 / F| ≤ 0.2; (2)

[0068] Wherein: F1 is the focal length of the first lens group; F is the focal length of the entire optical system in the infinity state; D12 is the interval between the first lens group and the second lens group in the infinity state, and the interval is the center distance between the lens surfaces.

[0069] In the above technical solution, the lens further satisfies the following conditional expressions:

[0070] 1 ≤ |F1 / F2| ≤ 5; (3)

[0071] Wherein: F1 is the focal length of the first lens group; F2 is the focal length of the second lens group.

[0072] In the above technical solution, the lens further satisfies the following conditional expressions:

[0073] 1 ≤ |F2 / F| ≤ 2.5; (4)

[0074] Wherein: F2 is the focal length of the second lens group; F is the focal length of the entire optical system in the infinity state.

[0075] Such as Figure 4As shown in the figure, the first lens group includes five lenses, which are the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, and the fifth lens 5 in sequence along the light incident direction; the first lens 1 is a negative lens convex towards the object side, the second lens 2 is a negative lens convex towards the object side, the third lens 3 is a biconcave negative lens, the fourth lens 4 is a positive lens convex towards the image side, and the fifth lens 5 is a positive lens convex towards the object side; the second lens group includes nine lenses, which are 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, the thirteenth lens 13, and the fourteenth lens 14 in sequence along the light incident direction; the eighth lens 8 and the ninth lens 9 are arranged with their mirror surfaces closely attached, and the eleventh lens 11 and the twelfth lens 12 are arranged with their mirror surfaces closely attached; the sixth lens 6 is a biconvex positive lens, the seventh lens 7 is a negative lens convex towards the object side, the eighth lens 8 is a biconcave negative lens, the ninth lens 9 is a biconvex positive lens, the tenth lens 10 is a positive lens convex towards the image side, the eleventh lens 11 is a negative lens convex towards the object side, the twelfth lens 12 is a biconvex positive lens, the thirteenth lens 13 is a biconvex positive lens, and the fourteenth lens 14 is a positive lens convex towards the object side; the aperture stop is arranged between the seventh lens 7 and the eighth lens 8 of the second lens group and moves axially with the second lens group.

[0076] The specific parameters of the lens structure data in this embodiment are as follows:

[0077] Focal length: 35.08; Aperture size Fno: 1.0500; Half field of view angle: 31.59°;

[0078] R (mm) D (mm) Nd Vd First lens 78.30 2 1.945958 17.9439 40.15 7.23 Second lens 87.59 2 1.769476 21.9168 42.88 13.8 Third lens -124.8 2 1.535856 47.1155 110.352 4.14 Fourth lens -1285.74 5.17 2.0006 25.435 -123.1 0.1 Fifth lens 115.5846 5.44 1.957022 19.1351 1046.7267 D(10) Sixth lens 55.2664 16.75 1.689552 49.8027 -110.9671 12.1588 Seventh lens 141.4935630167 3.5 1.534564 47.7391 32.9 7.9029 Diaphragm 1e+018 9.5951 Eighth lens -32.85 2 1.817382 22.9431 Ninth lens 161.59 8.3 1.782362 44.4945 -48.8118 0.1 Tenth lens -237.33 4.627 1.883004 44.4945 -73.45 0.1 Eleventh lens 783.93 2 1.791209 23.3470 Twelfth lens 62.4 10.2 1.499806 80.5599 -124.90 0.1 Thirteenth lens 214.82 4.9561 1.883004 40.8109 -275.74 0.1 Fourteenth lens 89.97 5.3174 1.883004 40.8109 670.57 D(27)

[0079] Object distance 500 inf D(10) 1.78 4.69 D(27) 39.39 36.82

[0080] Wherein: R (mm) is the curvature radius of each surface; D (mm) is the interval between each lens and the lens thickness; Nd is the refractive index of each glass for the d-line; Vd is the Abbe number of the glass.

[0081] The MTF (Modulation Transfer Function) curve graph of the lens in this embodiment is as shown in Figure 5 shown, and the distortion curve graph is as shown in Figure 6 shown. It can be seen that the performance of the lens in this embodiment is very good, meeting the usage requirements of a short focal length and ultra-large aperture single-lens reflex full-frame lens with high imaging quality.

Claims

1. An ultra-large aperture single-lens reflex full-frame lens, in which a first lens group with a negative diopter, a diaphragm, and a second lens group with a positive diopter are sequentially arranged along the light incident direction; the number of lens groups with diopters in the ultra-large aperture single-lens reflex full-frame lens is two groups; characterized in that, The diaphragm is located at any position in the second lens group; when the object is focused from infinity to a close distance, the first lens group remains stationary, and the second lens group, as the focusing group, axially moves from the image plane side towards the object side; and the lens satisfies the following conditional expressions: 2.5 ≤ |F1 / F| ≤ 7; (1) 0.05 ≤ |D12 / F| ≤ 0.2; (2) Where: F1 is the focal length of the first lens group; F is the focal length of the entire optical system in the infinity state; D12 is the interval between the first lens group and the second lens group in the infinity state, and the interval is the center distance between the lens surfaces; The first lens group includes 4 lenses, which are, in order of the light incident direction, the first lens, the second lens, the third lens, and the fourth lens; the first lens is a negative lens convex towards the object side, the second lens is a negative lens convex towards the object side, the third lens is a biconcave negative lens, and the fourth lens is a biconvex positive lens; the second lens group includes 9 lenses, which are, in order of the light incident direction, 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 thirteenth lens; the tenth lens and the eleventh lens are in close contact with each other on the lens surfaces; the fifth lens is a biconvex positive lens, the sixth lens is a positive lens convex towards the object side, the seventh lens is a negative lens convex towards the object side, the eighth lens is a negative lens convex towards the object side, the ninth lens is a biconvex positive lens, the tenth lens is a biconcave negative lens, the eleventh lens is a biconvex positive lens, the twelfth lens is a biconvex positive lens, and the thirteenth lens is a positive lens convex towards the object side.

2. An ultra-large aperture single-lens reflex full-frame lens, in which a first lens group with a negative diopter, a diaphragm, and a second lens group with a positive diopter are sequentially arranged along the light incident direction; the number of lens groups with diopters in the ultra-large aperture single-lens reflex full-frame lens is two groups; characterized in that, The diaphragm is located at any position in the second lens group; when the object is focused from infinity to a close distance, the first lens group remains stationary, and the second lens group, as the focusing group, axially moves from the image plane side towards the object side; and the lens satisfies the following conditional expressions: 2.5 ≤ |F1 / F| ≤ 7; (1) 0.05 ≤ |D12 / F| ≤ 0.2; (2) Where: F1 is the focal length of the first lens group; F is the focal length of the entire optical system in the infinity state; D12 is the interval between the first lens group and the second lens group in the infinity state, and the interval is the center distance between the lens surfaces; The first lens group includes five lenses, which are, in sequence along the light incident direction, a first lens, a second lens, a third lens, a fourth lens, and a fifth lens; the first lens is a negative lens convex toward the object side, the second lens is a negative lens convex toward the object side, the third lens is a biconcave negative lens, the fourth lens is a positive lens convex toward the image side, and the fifth lens is a positive lens convex toward the object side; the second lens group includes nine lenses, which are, in sequence along the light incident direction, a sixth lens, 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; the eighth lens and the ninth lens are in mirror-to-mirror contact, and the eleventh lens and the twelfth lens are in mirror-to-mirror contact; the sixth lens is a biconvex positive lens, the seventh lens is a negative lens convex toward the object side, the eighth lens is a biconcave negative lens, the ninth lens is a biconvex positive lens, the tenth lens is a positive lens convex toward the image side, the eleventh lens is a negative lens convex toward the object side, the twelfth lens is a biconvex positive lens, the thirteenth lens is a biconvex positive lens, and the fourteenth lens is a positive lens convex toward the object side.

3. The ultra-large aperture single-lens reflex full-frame lens according to claim 1 or 2, characterized in that, The lens further satisfies the following conditional formula: 1 ≤ |F1 / F2| ≤ 5; (3) Where: F1 is the focal length of the first lens group; F2 is the focal length of the second lens group.

4. The ultra-large aperture single-lens reflex full-frame lens according to claim 1 or 2, characterized in that, The lens further satisfies the following conditional formula: 1 ≤ |F2 / F| ≤ 2.5; (4) Where: F2 is the focal length of the second lens group; F is the focal length of the entire optical system in the infinite far state.

5. The ultra-large aperture single-lens reflex full-frame lens according to claim 1 or 2, characterized in that, All lenses of the first lens group and the second lens group are spherical lenses; the focal length of the second lens group is greater than that of the first lens group.

6. The ultra-large aperture single-lens reflex full-frame lens according to claim 1 or 2, characterized in that, The focal length of the lens is 34 mm to 37 mm, and the aperture size is F0.90 to F1.

15.

7. The ultra-large aperture single-lens reflex full-frame lens according to claim 1 or 2, characterized in that, The lens is applied to digital cameras, video cameras, or used by adapting to mirrorless cameras.

8. The ultra-large aperture single-lens reflex full-frame lens according to claim 1, characterized in that, The distance between the first lens and the second lens of the first lens group is 5.00 to 7.00 mm, the distance between the second lens and the third lens is 11.00 to 14.00 mm, and the distance between the third lens and the fourth lens is 10.00 to 13.00 mm; the refractive index range of the first lens of the first lens group is 1.85 to 1.95, and the Abbe number range is 39 to 41; the refractive index range of the second lens is 1.70 to 1.80, and the Abbe number range is 46 to 48; the refractive index range of the third lens is 1.45 to 1.55, and the Abbe number range is 69 to 71; the refractive index range of the fourth lens is 1.85 to 1.95, and the Abbe number range is 30 to 32; The distance between the fifth lens and the sixth lens of the second lens group is 0.00 to 1.00 mm, the distance between the sixth lens and the seventh lens is 7.00 to 9.00 mm, the distance between the seventh lens and the eighth lens is 6.00 to 8.00 mm, the distance between the eighth lens and the ninth lens is 3.00 to 4.00 mm, the distance between the ninth lens and the tenth lens is 4.50 to 7.50 mm, the distance between the tenth lens and the eleventh lens is 0 mm, the distance between the eleventh lens and the twelfth lens is 0.00 to 1.00 mm, and the distance between the twelfth lens and the thirteenth lens is 0.00 to 1.00 mm; the adjustment distance range between the first lens group and the second lens group is 0.5 mm to 5 mm, that is, the adjustment distance range between the fourth lens and the fifth lens is 0.5 mm to 5 mm; the refractive index range of the fifth lens of the second lens group is 1.45 to 1.55, and the Abbe number range is 80 to 82; the refractive index range of the sixth lens is 1.85 to 1.95, and the Abbe number range is 40 to 42; the refractive index range of the seventh lens is 1.60 to 1.70, and the Abbe number range is 33 to 35; the refractive index range of the eighth lens is 1.80 to 1.90, and the Abbe number range is 22 to 24; the refractive index range of the ninth lens is 1.85 to 1.95, and the Abbe number range is 39 to 41; the refractive index range of the tenth lens is 1.80 to 1.90, and the Abbe number range is 22 to 24; the refractive index range of the eleventh lens is 1.45 to 1.55, and the Abbe number range is 80 to 82; the refractive index range of the twelfth lens is 1.85 to 1.95, and the Abbe number range is 39 to 41; the refractive index range of the thirteenth lens is 1.85 to 1.95, and the Abbe number range is 40 to 42.

9. The ultra-large aperture single-lens reflex full-frame lens according to claim 2, characterized in that, The distance between the first lens and the second lens of the first lens group is 5.50 to 7.50 mm, the distance between the second lens and the third lens is 12.00 to 14.00 mm, the distance between the third lens and the fourth lens is 3.00 to 5.00 mm, and the distance between the fourth lens and the fifth lens is 0 to 1 mm; the refractive index range of the first lens of the first lens group is 1.85 to 1.95, and the Abbe number range is 15 to 20; the refractive index range of the second lens is 1.70 to 1.80, and the Abbe number range is 18 to 24; the refractive index range of the third lens is 1.50 to 1.65, and the Abbe number range is 45 to 50; the refractive index range of the fourth lens is 1.95 to 2.05, and the Abbe number range is 22 to 27, and the refractive index range of the fifth lens is 1.90 to 2.00, and the Abbe number range is 17 to 21; The distance between the sixth lens and the seventh lens of the second lens group is 9.00 to 13.00 mm, the distance between the seventh lens and the eighth lens is 16.00 to 19.50 mm, the distance between the eighth lens and the ninth lens is 0 mm, the distance between the ninth lens and the tenth lens is 0.00 to 1.00 mm, the distance between the tenth lens and the eleventh lens is 0.00 to 1.00 mm, the distance between the eleventh lens and the twelfth lens is 0 mm, the distance between the twelfth lens and the thirteenth lens is 0.00 to 1.00 mm, and the distance between the thirteenth lens and the fourteenth lens is 0.00 to 1.00 mm; the adjustment distance range between the first lens group and the second lens group is 0.5 mm to 5 mm, that is, the adjustment distance range between the fifth lens and the sixth lens is 0.5 mm to 5 mm; the refractive index range of the sixth lens of the second lens group is 1.65 to 1.75, and the Abbe number range is 45 to 50; the refractive index range of the seventh lens is 1.50 to 1.60, and the Abbe number range is 45 to 50; the refractive index range of the eighth lens is 1.75 to 1.85, and the Abbe number range is 20 to 25; the refractive index range of the ninth lens is 1.75 to 1.85, and the Abbe number range is 39 to 46; the refractive index range of the tenth lens is 1.85 to 1.95, and the Abbe number is 44.4945; the refractive index range of the eleventh lens is 1.75 to 1.85, and the Abbe number range is 22 to 24; the refractive index range of the twelfth lens is 1.45 to 1.55, and the Abbe number range is 80 to 82; the refractive index range of the thirteenth lens is 1.85 to 1.95, and the Abbe number range is 39 to 41; the refractive index range of the fourteenth lens is 1.85 to 1.95, and the Abbe number range is 40 to 42.

Images