A lens and a camera device

Abstract

The present application relates to the technical field of zoom lenses, and provides a lens and an imaging device. The lens includes a first lens group and a second lens group having positive optical power, and a third lens group having negative optical power. The first lens group, the second lens group, and the third lens group are arranged in sequence along the optical axis from the object side to the image side; when the lens zooms from infinity to a near distance, the first lens group and the third lens group are fixed relative to the image plane, and the second lens group moves toward the object side; the focal length of the lens and the focal length of the first lens group satisfy: 1≤F1 / F≤2, where F represents the focal length of the lens, and F1 represents the combined focal length of the first lens group. The position of the entrance pupil is closer to the object side and the size of the entrance pupil decreases accordingly. In the case of the same field of view angle, the intersection point of the principal ray and the lens is closer to the optical axis, and various aberrations of the first lens group are reduced accordingly. Only a small amount of correction is required to eliminate each aberration factor, reducing the diameter of the first lens group and the sizes of the individual lenses in the lens.

Description

Technical Field

[0001] The present application relates to the technical field of zoom lenses, and in particular to a lens and a camera device. Background Art

[0002] In the field of zoom lenses, imaging lenses with a field of view of 55° to 75° are usually called full-frame standard portrait lenses. They are suitable for portrait photography at a distance of 1.5m-2m from the lens, and the zoom range is usually 70mm to 135mm. For this type of lens, when the F number (also known as the aperture number, which is numerically equal to the inverse of the relative aperture, that is, the image distance / aperture execution) is large, a triplet structure is generally used, while for large-aperture standard lenses with an F number less than 2, a double Gauss structure is usually used. In a double Gauss lens, a relatively concave symmetrical structure is usually used on both sides of the aperture. Although such a lens structure has a large Petzval value and a large field curvature of the lens, it can effectively reduce spherical aberration and position chromatic aberration, thereby increasing the lens aperture while meeting the lens's requirements for high image quality.

[0003] In the traditional lens structure, since the double Gauss lens is a symmetrical structure, its focusing lens is often a lens group containing many lenses. It requires greater power and energy consumption during electric focusing, and the focusing speed is too slow and inaccurate. Summary of the invention

[0004] The purpose of the present application is to provide a lens, aiming to solve the technical problem that too many lenses need to be moved when focusing a traditional lens.

[0005] The present application is implemented as follows: a lens comprises a first lens group and a second lens group having positive power, and a third lens group having negative power, wherein the first lens group, the second lens group and the third lens group are arranged in sequence along the direction from the object side to the image side of the optical axis;

[0006] When the lens is zoomed from infinity to near, the first lens group and the third lens group are fixed relative to the image plane, and the second lens group moves toward the object side;

[0007] The focal length of the lens and the focal length of the first lens group satisfy:

[0008] 1≤F 1 / F≤2,

[0009] Where F is the focal length of the lens, F 1 represents the combined focal length of the first lens group.

[0010] In one embodiment of the present application, the first lens group includes a first negative lens, a second positive lens, a third negative lens, a fourth positive lens, and a fifth positive lens arranged in sequence along the optical axis from the object side to the image side, and the first negative lens satisfies:

[0011] 0.5 ≤ (R 11 + R 12 ) / (R 11 - R 12 ) ≤ 3,

[0012] wherein, R 11 represents the radius of curvature of the surface of the first negative lens facing the object side, and R 12 represents the radius of curvature of the surface of the first negative lens facing the image side.

[0013] In one embodiment of the present application, the lens further includes a diaphragm, and the diaphragm is coaxial with the lens and is disposed between the fourth positive lens and the fifth positive lens.

[0014] In one embodiment of the present application, the fourth positive lens satisfies:

[0015] 60 ≤ ν d4 ≤ 90,

[0016] wherein, ν d4 represents the Abbe number of the fourth positive lens.

[0017] In one embodiment of the present application, the fifth positive lens satisfies:

[0018] 1.8 ≤ n d ≤ 2.0,

[0019] wherein, n d represents the refractive index of the fifth positive lens.

[0020] In one embodiment of the present application, the second lens group includes an achromatic lens group and an eighth positive lens arranged in sequence along the optical axis from the object side to the image side. The achromatic lens group includes a sixth positive lens and a seventh negative lens that are closely attached, and the sixth positive lens and the seventh negative lens satisfy:

[0021] nd j1 ≤ nd j2 ; vd j1 ≥ vd j2 ,

[0022] wherein, nd j1 and nd j2 respectively represent the refractive indices of the sixth positive lens and the seventh negative lens, and vd j1 and vd j2respectively represent the Abbe numbers of the sixth positive lens and the seventh negative lens.

[0023] In an embodiment of the present application, the eighth positive lens is an aspherical lens, and the eighth positive lens satisfies:

[0024] 1.70 ≤ n d8 ≤ 1.90; 40 ≤ ν d8 ≤ 70,

[0025] wherein, n d8 represents the refractive index of the eighth positive lens, and ν d8 represents the Abbe number of the eighth positive lens.

[0026] In an embodiment of the present application, the third lens group satisfies:

[0027] -1.5 ≤ F 3 / F ≤ -0.7,

[0028] wherein, F 3 represents the focal length of the third lens group.

[0029] In an embodiment of the present application, the lens satisfies:

[0030] 0.3 ≤ B f / F ≤ 0.7,

[0031] wherein, B f represents the distance between the lens surface of the lens closest to the image plane and the image plane.

[0032] Another object of the present application is to provide an imaging device including the lens as described above.

[0033] Implementing a lens of the present application can at least achieve the following beneficial effects:

[0034] By setting the focal length of the first lens group within a range greater than or equal to the focal length of the lens and less than or equal to twice the focal length of the lens, the field of view range and the entrance pupil position of the lens can be optimized. Specifically, the position of the entrance pupil is closer to the object side and the size of the entrance pupil is correspondingly reduced. In this way, with the same field of view angle, the intersection point of the chief ray and the lens is closer to the optical axis, thereby reducing the diameter of the first lens group. Aberrations such as chromatic aberration, spherical aberration, coma, phase change, field curvature, and distortion of the first lens group are reduced accordingly. Only a small amount of correction is required to eliminate each aberration factor, and finally the sizes of the lenses in the lens are reduced. Description of the Drawings

[0035] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0036] Figure 1 It is a schematic structural diagram of the lens provided in Embodiment 1 of the present application;

[0037] Figure 2 is Figure 1 a graph showing the change trend of the longitudinal aberration when the lens in focuses on an object far from the lens;

[0038] Figure 3 is Figure 1 a graph showing the change trend of the field curvature and distortion when the lens in focuses on an object far from the lens;

[0039] Figure 4 is Figure 1 a graph showing the change trend of the longitudinal aberration when the lens in focuses at 0.35 meters;

[0040] Figure 5 is Figure 1 a graph showing the change trend of the field curvature and distortion when the lens in focuses at 0.35 meters;

[0041] Figure 6 It is a schematic structural diagram of the lens provided in Embodiment 2 of the present application;

[0042] Figure 7 is Figure 6 a graph showing the change trend of the longitudinal aberration when the lens in focuses on an object far from the lens;

[0043] Figure 8 is Figure 6 a graph showing the change trend of the field curvature and distortion when the lens in focuses on an object far from the lens;

[0044] Figure 9 is Figure 6 a graph showing the change trend of the longitudinal aberration when the lens in focuses at 0.35 meters;

[0045] Figure 10 is Figure 6 a graph showing the change trend of the field curvature and distortion when the lens in focuses at 0.35 meters;

[0046] Figure 2 , Figure 4 , Figure 7 and Figure 9The F-line, d-line, and C-line in it respectively represent the spherical aberration at the F-line (wavelength 486 nm), d-line (wavelength 588 nm), and C-line (wavelength 656 nm); Figure 3 , Figure 5 , Figure 8 and Figure 10 the S-line in it represents the value of the chief ray d-line on the sagittal image plane under the corresponding imaging conditions, and the T-line represents the value of the chief ray d-line on the meridional image plane under the corresponding imaging conditions.

[0047] The label details related to the above-mentioned drawings are as follows:

[0048] GR1 - the first lens group; G 11 - the first negative lens; G 12 - the second positive lens; G 13 - the third negative lens; G 14 - the fourth positive lens; G 15 - the fifth positive lens; GR2 - the second lens group; G 21 - the achromatic lens group; G j1 - the sixth positive lens; G j2 - the seventh negative lens; G 22 - the eighth positive lens; GR3 - the third lens group; G 31 - the ninth negative lens; GL - parallel glass plate; IMG - image plane; SP - diaphragm. Specific embodiments

[0049] In order to make the objectives, technical solutions, and advantages of this application clearer, the following further elaborates on this application in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0050] It should be noted that when a component is referred to as "fixed to" or "disposed on" another component, it can be directly or indirectly located on that other component. When a component is referred to as "connected to" another component, it can be directly or indirectly connected to that other component. The orientations or positions indicated by the terms "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientations or positions shown in the drawings and are only for convenience of description and cannot be construed as limitations on this technical solution. The terms "first", "second",..., "ninth" are only for convenience of description and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of technical features. The meaning of "a plurality" is two or more, unless otherwise specifically defined.

[0051] In order to illustrate the technical solutions described in this application, the following elaborates in detail in combination with specific drawings and embodiments.

[0052] Please refer to Figure 1 and Figure 6 , this embodiment provides a lens, including a first lens group GR1 with positive optical power, a second lens group GR2, and a third lens group GR3 with negative optical power. The first lens group GR1, the second lens group GR2, and the third lens group GR3 are sequentially arranged along the optical axis from the object side to the image side;

[0053] When the lens zooms from infinity to near, the first lens group GR1 and the third lens group GR3 are fixed relative to the image plane IMG, and the second lens group GR2 moves towards the object side;

[0054] The focal length of the lens and the focal length of the first lens group GR1 satisfy condition (1):

[0055] 1≤F 1 / F≤2,

[0056] wherein, F represents the focal length of the lens, and F 1 represents the combined focal length of the first lens group GR1.

[0057] Implementing a lens of the present application can at least achieve the following beneficial effects:

[0058] By setting the focal length of the first lens group GR1 within the range of being greater than or equal to the focal length of the lens and less than or equal to twice the focal length of the lens, the field of view range and the entrance pupil position of the lens can be optimized. Specifically, the position of the entrance pupil is closer to the object side and the size of the entrance pupil decreases accordingly. In this way, when the field of view angle is the same, the intersection point of the chief ray and the lens is closer to the optical axis, thereby reducing the diameter of the first lens group GR1. Aberrations such as chromatic aberration, spherical aberration, coma, phase change, field curvature, and distortion of the first lens group GR1 are reduced accordingly. Only a small amount of correction is required to eliminate each aberration factor, and finally the sizes of the lenses in the lens are reduced.

[0059] For the lens provided in this embodiment, when the ratio of the combined focal length of the first lens group GR1 to the focal length of the lens is lower than the lower limit value of condition (1), it will cause the focal length of the first lens group GR1 to be too small and the optical power to be too large. The lens aperture of the first lens group GR1 will increase accordingly. Aberrations such as spherical aberration generated by the first lens group GR1 are corrected by the second lens group GR2 and the third lens group GR3. Therefore, the structures of the second lens group GR2 and the third lens group GR3 will be more complex and there will be more lens elements, ultimately resulting in a decline in imaging quality and the lens structure being too complex, heavy, and bulky;

[0060] When the ratio of the combined focal length of the first lens group GR1 to the focal length of the lens is higher than the upper limit value of condition (1), it will make the total length of the lens too long, the lens structure too complex, heavy, and bulky, which is not conducive to the miniaturization of the lens and the portability is poor.

[0061] As a specific solution of this embodiment, the first lens group GR1 has an F number of 1.6 to 2.2 and a field of view angle of 55-75 degrees, and can be used as a large-aperture single-focus lens in an interchangeable lens device, and can be applied to photographic equipment such as cameras, video cameras, digital cameras, and broadcast cameras with interchangeable lenses.

[0062] Please refer to Figure 1 and Figure 6 , in an embodiment of the present application, the first lens group GR1 includes a first negative lens G arranged in sequence along the optical axis from the object side to the image side 11 , a second positive lens G 12 , a third negative lens G 13 , a fourth positive lens G 14 , and a fifth positive lens G 15 , and the first negative lens G 11 satisfies condition (2):

[0063] 0.5 ≤ (R 11 + R 12 ) / (R 11 - R 12 ) ≤ 3,

[0064] where, R 11 represents the radius of curvature of the surface of the first negative lens G11 facing the object side, and R 12 represents the radius of curvature of the surface of the first negative lens G 11 facing the image side.

[0065] Essentially, condition (2) limits the focal length range of the first negative lens G 11 , and the first negative lens G 11 that meets this condition has sufficient negative optical power to offset the positive optical power of other lenses in the first lens group GR1, reducing the chromatic aberration of the lens; at the same time, the positive optical power of the first lens group GR1 will not be too small, and the lens does not need to be set too long, which is beneficial to the miniaturization of the lens.

[0066] If the ratio of the sum of the radii of curvature of the two surfaces of the first negative lens G 11 to the difference between the radii of curvature of the two surfaces is lower than the lower limit of condition (2), then the negative optical power of the first negative lens G 11 is too large. In this case, the overall positive optical power of the first lens group GR1 is too small, and the overall length of the lens needs to be set longer, which is not conducive to the miniaturization and portability of the lens;

[0067] If the ratio of the sum of the radii of curvature of the two surfaces of the first negative lens G 11 to the difference between the radii of curvature of the two surfaces is higher than the upper limit of condition (2), it will cause the first negative lens G 11If the negative optical power is too small, it means that the positive optical power of the entire first lens group GR1 is too high, and the refractive power of each band of light varies greatly, resulting in an increase in longitudinal chromatic aberration and affecting the overall imaging quality of the lens.

[0068] Please refer to Figure 1 and Figure 6 , in an embodiment of the present application, the lens further includes a diaphragm SP, and the diaphragm SP is coaxial with the lens and disposed between the fourth positive lens G 14 and the fifth positive lens G 15 .

[0069] In an embodiment of the present application, the fourth positive lens G 14 satisfies condition (3):

[0070] 60 ≤ ν d4 ≤ 90,

[0071] where ν d4 represents the Abbe number of the fourth positive lens G 14 .

[0072] Condition (3) stipulates the dispersion coefficient of the fourth positive lens G 14 in the first lens group GR1. The dispersion coefficient of the fourth positive lens G 14 determines the correction degree of the longitudinal chromatic aberration and lateral chromatic aberration of the first lens group GR1, and is an important factor affecting the imaging performance. Limiting the Abbe number of the fourth positive lens G 14 between 60 and 90 can reduce the production cost of the lens without affecting the performance of the lens.

[0073] Specifically, if the dispersion coefficient of the fourth positive lens G 14 is lower than the lower limit of condition (3), the ability of the fourth positive lens G 14 to correct the two chromatic aberrations is weak, which is not conducive to the correction of the chromatic aberration of the entire imaging lens; if the dispersion coefficient of the fourth positive lens G 14 is higher than the upper limit of condition (3), since the material with an Abbe number exceeding 90 is extremely expensive, using a material with an Abbe number above 90 to manufacture the fourth positive lens G 14 will increase the cost of the lens and also result in excessive correction performance.

[0074] It should be understood that the Abbe number mentioned in all embodiments of the present application refers to the Abbe number of the lens material with respect to the d-line (wavelength 587.56 nm), specifically, ν d =(n d -1) / (n F -n C ), where n d is the refractive index of the medium for the light with a wavelength of 587.56 nm, and n Fis the refractive index of the medium for light with a wavelength of 486.13 nm, n C is the refractive index of the medium for light with a wavelength of 656.27 nm.

[0075] In an embodiment of the present application, the fifth positive lens G 15 satisfies condition (4):

[0076] 1.8 ≤ n d ≤ 2.0,

[0077] wherein, n d represents the refractive index of the fifth positive lens G 15 of the first lens group GR1.

[0078] Condition (4) stipulates the refractive index range for the selection of materials for the fifth positive lens G 15 of the first lens group GR1. If the refractive index of the fifth positive lens G 15 is higher than the upper limit of condition (4), the optical power of the fifth positive lens G 15 is too large, the longitudinal chromatic aberration shifts in the positive direction, and the first lens group GR1 has insufficient correction ability for longitudinal chromatic aberration, resulting in poor imaging quality at positions far from the imaging center; if the refractive index of the fifth positive lens G 15 is lower than the lower limit of condition (4), the optical power of the fifth positive lens G 15 is too small, the distortion shifts in the direction of barrel distortion, and the first lens group GR1 has insufficient correction ability for barrel distortion, which will also lead to poor imaging quality at positions far from the imaging center.

[0079] Please refer to Figure 1 and Figure 6 , in an embodiment of the present application, the second lens group GR2 includes an achromatic lens group G 21 and an eighth positive lens G 22 arranged in sequence along the optical axis from the object side to the image side. The achromatic lens group G 21 includes a sixth positive lens G j1 and a seventh negative lens G j2 which are closely attached. The sixth positive lens G j1 and the seventh negative lens G j2 satisfy condition (5):

[0080] nd j1 ≤ nd j2 ; vd j1 ≥ vd j2 ,

[0081] wherein, nd j1 and nd j2 respectively represent the refractive indices of the sixth positive lens G j1 and the seventh negative lens G j2 , and vd j1and vd j2 respectively represent the Abbe number of the sixth positive lens G j1 and the seventh negative lens G j2 .

[0082] Conditional formula (5) respectively stipulates the relationship between the refractive index and the Abbe number of the materials of the sixth positive lens G 21 and the seventh negative lens G j1 in the achromatic lens group G j2 . The achromatic lens group G j1 composed of the sixth positive lens G j2 and the seventh negative lens G 21 , which not only can correct chromatic aberration, but also can significantly reduce spherical aberration, and can significantly improve the imaging quality of the lens.

[0083] In an embodiment of the present application, the eighth positive lens G 22 adopts an aspherical lens, and the eighth positive lens G 22 satisfies the condition (6):

[0084] 1.70 ≤ n d8 ≤ 1.90; 40 ≤ ν d8 ≤ 70,

[0085] wherein, n d8 represents the refractive index of the eighth positive lens G 22 , and ν d8 represents the Abbe number of the eighth positive lens G 22 .

[0086] Conditional formula (6) respectively stipulates the refractive index and the Abbe number of the eighth positive lens G 22 . If the refractive index and the Abbe number of the eighth positive lens G 22 are lower than the lower limit of the condition (6), due to the too low refractive index and Abbe number of the eighth positive lens G 22 , the eighth positive lens G 22 cannot meet the requirements of the lens for the correction effect of spherical aberration and cannot balance the spherical aberration of the whole system; if the refractive index and the Abbe number of the eighth positive lens G 22 are higher than the upper limit of the condition (6), then due to the relatively soft texture of the high refractive index glass, the material of the eighth positive lens G 22 will become difficult to form, which puts too high requirements on the processing and manufacturing and production process of the lens, resulting in too high production cost of the lens.

[0087] In an embodiment of the present application, the third lens group GR3 satisfies the condition (7):

[0088] -1.5 ≤ F 3 / F ≤ -0.7,

[0089] wherein, F3 represents the focal length of the third lens group GR3.

[0090] Condition (7) specifies the light incident angle of the third lens group GR3. By using a negative lens that satisfies conditional expression (7) to form the third lens group GR3, the imaging quality of the lens can be optimized. If the ratio of the focal length of the third lens group GR3 to the focal length of the lens is higher than the upper limit specified by condition (7), it will result in too large a optical power of the third lens group GR3. As a result, the third lens group GR3 will generate too large a negative spherical aberration, causing the negative spherical aberration of the lens to be too large to be corrected; conversely, if the ratio of the focal length of the third lens group GR3 to the focal length of the lens is lower than the lower limit specified by condition (7), the optical power of the negative lens is too small, resulting in too small a negative spherical aberration and an excess of positive spherical aberration. Both of the above situations will affect the imaging quality of the lens.

[0091] Please refer to Figure 1 and Figure 6 , as a specific solution of this embodiment, the third lens group GR3 includes the ninth negative lens G 31 , the ninth negative lens G 31 satisfies condition (7).

[0092] In an embodiment of the present application, the lens satisfies condition (8):

[0093] 0.3 ≤ B f / F ≤ 0.7,

[0094] wherein, B f represents the distance between the lens surface of the lens closest to the image plane IMG and the image plane IMG.

[0095] Conditional expression (8) specifies the ratio of the distance between the lens surface of the lens closest to the image plane IMG and the image plane IMG to the focal length of the lens. A lens that meets condition (8) has excellent optical performance, and the ratio of the back focal length of the lens to the focal length of the lens is appropriate, making the lens suitable for cameras with interchangeable imaging lenses such as mirrorless cameras.

[0096] Specifically, if the ratio of the distance between the lens surface of the lens closest to the image plane IMG and the image plane IMG to the focal length of the lens is lower than the lower limit specified by condition (8), the back focal length becomes too short relative to the focal length of the lens, making it difficult to obtain a lens suitable for a mirrorless camera; if the ratio of the distance between the lens surface of the lens closest to the image plane IMG and the image plane IMG to the focal length of the lens is higher than the upper limit specified by condition (8), the back focal length becomes relatively too long relative to the focal length of the lens, there is strong field curvature, so it is difficult to correct distortion, affecting the final imaging quality of the lens.

[0097] Another object of the present application is to provide an imaging device including the lens in the foregoing embodiment.

[0098] The following uses several specific embodiments to illustrate the technical effects of the lens provided by the present application:

[0099] Embodiment 1

[0100] Please refer to Figure 1 , in this embodiment, the lens includes a first lens group GR1 with a positive focal power, a second lens group GR2, and a third lens group GR3 with a negative focal power, which are sequentially arranged along the optical axis from the object side to the image side. The first lens group GR1 includes a first negative lens G 11 , a second positive lens G 12 , a third negative lens G 13 , a fourth positive lens G 14 , and a fifth positive lens G 15 . The second lens group GR2 includes a sixth positive lens G j1 , a seventh negative lens G j2 , and an eighth positive lens G 22 . The sixth positive lens G j1 and the seventh negative lens G j2 are closely attached. The eighth positive lens G 22 is an aspherical lens. The third lens group GR3 includes a ninth negative lens G 31 . For the lens provided in this embodiment, during the focusing process, the second lens group GR2 moves along the optical axis, and the first lens group GR1 and the third lens group GR3 are fixed relative to the image plane.

[0101] Please refer to Figure 1 , in this embodiment, optionally, a parallel glass plate GL is provided between the negative lens of the third lens group GR3 and the image plane IMG. A filter layer is provided on the surface of the parallel glass plate GL to protect the color sensor provided on the image plane IMG.

[0102] The following shows the numerical data of each component of the imaging lens in this embodiment.

[0103] The following table shows the basic data of the lens:

[0104]

[0105]

[0106] The aspherical data (surface parameters of the eighth positive lens G 22 ) of the lens in Embodiment 1 are as follows:

[0107]

[0108]

[0109] Figures 2 to 5 Shows the imaging parameters when the lens pair provided in this embodiment focuses on an object far from the lens and when focusing in the near field. Among them, Figure 2 Is a graph showing the changing trend of the longitudinal aberration when the lens provided in this embodiment focuses on an object far from the lens; Figure 3 Is a graph showing the changing trends of the field curvature and distortion when the lens provided in this embodiment focuses on an object far from the lens; Figure 4 Is a graph showing the changing trend of the longitudinal aberration when the lens provided in this embodiment focuses at 0.35 meters; Figure 5 Is a graph showing the changing trends of the field curvature and distortion when the lens provided in this embodiment focuses at 0.35 meters. It can be seen that the lens provided in this embodiment can effectively eliminate longitudinal aberration, field curvature, and distortion at each imaging distance, has small chromatic aberration, and especially has an excellent near-field portrait photography effect.

[0110] Embodiment Two

[0111] Please refer to Figure 6 , this embodiment is a parallel solution to Embodiment One. The actual composition of the lens is the same as that of the lens in Embodiment One, and the difference lies in the specific parameter settings of the lens. Specifically, the numerical data of the lens provided in this embodiment are as follows.

[0112] The basic data of the lens provided in this embodiment are as follows

[0113]

[0114] The aspherical data (the surface parameters of the eighth positive lens G) of the lens in Embodiment Two are as follows: 22

[0115]

[0116]

[0117]

[0118] Figures 7 to 10 Shows the imaging parameters when the lens pair provided in this embodiment focuses on an object far from the lens and when focusing in the near field. Among them, Figure 7 Is a graph showing the changing trend of the longitudinal aberration when the lens provided in this embodiment focuses on an object far from the lens; Figure 8 Is a graph showing the changing trends of the field curvature and distortion when the lens provided in this embodiment focuses on an object far from the lens; Figure 9 Is a graph showing the changing trend of the longitudinal aberration when the lens provided in this embodiment focuses at 0.35 meters; Figure 10 ​It is a graph showing the variation trends of field curvature and distortion when the lens provided in this embodiment is focused at 0.35 meters. It can be seen that the lens provided in this embodiment can effectively eliminate longitudinal aberration, field curvature and distortion at each imaging distance, has small chromatic aberration, and especially has excellent near-field portrait photography effect.

[0119] The lenses provided in Embodiment 1 and Embodiment 2 both meet the above conditions. For details, please see the following table:

[0120]

[0121]

[0122] It should be noted that the specific parameters in the above table are only illustrative. The parameters of each lens are not limited to the values shown in the above numerical examples, and other values can be adopted, and similar or the same technical effects can be achieved.

[0123] The above are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A lens, characterized in that, it includes a first lens group and a second lens group with positive optical power, and a third lens group with negative optical power, and the first lens group, the second lens group and the third lens group are arranged in sequence along the optical axis from the object side to the image side; when the lens zooms from infinity to a near distance, the first lens group and the third lens group are fixed relative to the image plane, and the second lens group moves towards the object side; the focal length of the lens and the focal length of the first lens group satisfy: 1 ≤ F 1 / F ≤ 2, Among them, F represents the focal length of the lens, and F 1 represents the combined focal length of the first lens group; the first lens group has an F number of 1.6 to 2.2; the first lens group includes a first negative lens, a second positive lens, a third negative lens, a fourth positive lens, and a fifth positive lens arranged in sequence along the optical axis from the object side to the image side, and the first negative lens satisfies: 0.5 ≤ (R 11 + R 12 ) / (R 11 - R 12 ) ≤ 3, wherein, R 11 represents the radius of curvature of the surface of the first negative lens facing the object side, and R 12 represents the radius of curvature of the surface of the first negative lens facing the image side.

2. The lens according to claim 1, characterized in that, the lens further includes a diaphragm, and the diaphragm is coaxial with the lens and is arranged between the fourth positive lens and the fifth positive lens.

3. The lens according to claim 1, characterized in that, the fourth positive lens satisfies: 60 ≤ ν d4 ≤ 90, Among them, ν d4 represents the Abbe number of the fourth positive lens.

4. The lens according to claim 1, characterized in that, the fifth positive lens satisfies: 1.8 ≤ n d ≤ 2.0， where n d represents the refractive index of the fifth positive lens.

5. The lens according to claim 1, characterized in that, the second lens group includes an achromatic lens group and an eighth positive lens arranged in sequence along the optical axis from the object side to the image side, the achromatic lens group includes a sixth positive lens and a seventh negative lens that are closely attached, and the sixth positive lens and the seventh negative lens satisfy: nd j1 ≤nd j2 ;vd j1 ≥vd j2 , wherein, nd j1 and nd j2 respectively represent the refractive indices of the sixth positive lens and the seventh negative lens, and vd j1 and vd j2 respectively represent the Abbe numbers of the sixth positive lens and the seventh negative lens.

6. The lens according to claim 5, characterized in that, the eighth positive lens is an aspherical lens, and the eighth positive lens satisfies: 1.70 ≤ n d8 ≤ 1.90; 40 ≤ ν d8 ≤ 70, where n d8 represents the refractive index of the eighth positive lens, and ν d8 represents the Abbe number of the eighth positive lens.

7. The lens according to claim 1, characterized in that, the third lens group satisfies: -1.5 ≤ F 3 / F ≤ -0.7, Among them, F 3 represents the focal length of the third lens group.

8. The lens according to any one of claims 1-7, characterized in that, the lens satisfies: 0.3 ≤ B f / F ≤ 0.7, Among them, B f represents the distance between the lens surface of the lens closest to the image plane and the image plane.

9. An imaging device, characterized in that, it includes the lens according to any one of claims 1-8.

Images