Telephoto lens

Abstract

This invention relates to a telephoto lens, comprising a first lens group (G1), a second lens group (G2), a third lens group (G3), and a fourth lens group (G4) arranged sequentially along the optical axis from the object side to the image side. The third lens group (G3) is movable along the optical axis, and the second lens group (G2) is movable in a direction perpendicular to the optical axis. The first lens group (G1) has positive optical power, the second lens group (G2) has negative optical power, the third lens group (G3) has positive optical power, and the fourth lens group (G4) has negative optical power. The telephoto lens of this invention features a long focal length, optical image stabilization, and confocal focusing of visible and infrared light, thus solving the problem of large temperature drift at long focal lengths.

Description

Technical Field

[0001] This invention relates to the field of optical imaging technology, and more particularly to a telephoto lens. Background Technology

[0002] With the rapid development of highway transportation construction and the dramatic increase in the number of urban vehicles, the construction and application of video surveillance systems are receiving increasing attention to ensure traffic safety and order. For complex environments such as cities, ports, and airports, standard lenses are generally insufficient, requiring telephoto lenses capable of ultra-long-range monitoring to obtain high-quality video images. However, due to environmental factors such as strong winds, monitoring equipment can experience shaking, resulting in blurred images and an inability to accurately identify targets, thus affecting the effectiveness of video surveillance. Existing highway video surveillance anti-shake methods largely employ digital image stabilization (DIS) technology. This type of electronic stabilization compensates for shaking by reducing image quality, relying entirely on digital processing technology. However, while electronic stabilization achieves a lower cost by striking a balance between image quality and image shake, its effectiveness is relatively poor, especially when the lens is at a telephoto distance, where the image resolution drops significantly. Furthermore, telephoto lenses experience greater defocusing in high and low temperature environments. Summary of the Invention

[0003] The purpose of this invention is to provide a telephoto lens.

[0004] To achieve the above-mentioned objective, the present invention provides a telephoto lens comprising a first lens group, a second lens group, a third lens group, and a fourth lens group arranged sequentially along the optical axis from the object side to the image side. The third lens group is movable along the optical axis, the second lens group is movable in a direction perpendicular to the optical axis, the first lens group has positive optical power, the second lens group has negative optical power, the third lens group has positive optical power, and the fourth lens group has negative optical power.

[0005] According to one aspect of the present invention, the first lens group includes a first lens with positive optical power, an aperture stop, a second lens with positive optical power, a third lens with positive or negative optical power, a fourth lens with positive or negative optical power, a fifth lens with positive or negative optical power, and a sixth lens with positive or negative optical power, arranged sequentially along the optical axis from the object side to the image side.

[0006] According to one aspect of the present invention, the first lens is a convex-concave lens, the second lens is a convex-convex lens, the third lens is a concave-concave or convex-convex lens, the fourth lens is a convex-convex, concave-concave, or convex-flat lens, the fifth lens is a concave-concave, convex-concave, or convex-convex lens, and the sixth lens is a convex-concave or concave-concave lens.

[0007] According to one aspect of the invention, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are combined to form at least one cemented lens assembly.

[0008] According to one aspect of the invention, the second lens group includes a seventh lens with negative optical power.

[0009] According to one aspect of the invention, the seventh lens is a convex-concave lens.

[0010] According to one aspect of the invention, the third lens group includes an eighth lens with positive optical power.

[0011] According to one aspect of the invention, the eighth lens is a convex-concave lens.

[0012] According to one aspect of the invention, the fourth lens group includes a ninth lens with negative optical power and a tenth lens with positive optical power, arranged sequentially along the optical axis from the object side to the image side.

[0013] According to one aspect of the invention, the ninth lens is a convex-concave or concave-concave lens, and the tenth lens is a convex-convex or convex-concave lens.

[0014] According to one aspect of the invention, the focal length F2 of the second lens group and the focal length F of the telephoto lens satisfy the following relationship: -0.2≤F2 / F≤-0.15.

[0015] According to one aspect of the invention, the focal length F of the telephoto lens and the focal length F3 of the third lens group satisfy the following relationship: 0.15≤F3 / F≤0.35.

[0016] According to one aspect of the invention, the distance d1 from the aperture to the second lens satisfies the following condition: 30≤d1≤85.

[0017] According to one aspect of the invention, the total length L of the telephoto lens and the focal length F of the telephoto lens satisfy the following relationship: 0.5≤L / F≤0.8.

[0018] According to one aspect of the invention, the refractive index Nd of the second lens L2 And Abbe number Vd L2 Each of the following conditions must be met: 1.4 ≤ Nd L2 ≤1.6; 60≤Vd L2 ≤90.

[0019] According to one aspect of the invention, the back focal length BF of the telephoto lens and the focal length F of the telephoto lens satisfy the following relationship: 0.005≤BF / F≤0.042.

[0020] According to the present invention, a telephoto lens with a large focal length, optical image stabilization, the ability to solve the problem of large temperature drift at long focal lengths, and the ability to co-focus visible and infrared light is provided.

[0021] According to one aspect of the present invention, by rationally setting the positive and negative optical power of each lens group, the incident light can be collected and imaged effectively, various aberrations and chromatic aberrations can be corrected, while ensuring no defocusing at high and low temperatures. Furthermore, the use of negative optical power group image stabilization helps reduce the burden on the drive system.

[0022] According to one aspect of the present invention, by rationally combining the positive and negative lenses in the first lens group, imaging light can be collected effectively, which is beneficial for correcting spherical aberration, astigmatism, chromatic aberration, and high / low temperature performance of the first lens group. Simultaneously, it can reduce intra-group tolerance sensitivity and ensure image uniformity. Furthermore, the concave-convex design further facilitates the collection of imaging light, achieving large-aperture imaging and effectively correcting spherical aberration, astigmatism, and high / low temperature performance. The second, third, fourth, fifth, and sixth lenses are combined to form at least one cemented lens group. Thus, by rationally using the cemented lens group, chromatic aberration, spherical aberration, and temperature performance can be significantly corrected, while easily ensuring tolerance sensitivity. By using negative refractive power lenses to reduce the refractive power of positive lenses, the lens can better achieve full-frame imaging with a large image plane and a smaller principal ray incident angle, resulting in better color reproduction.

[0023] According to one aspect of the present invention, the second lens group can move along a direction perpendicular to the optical axis, thereby correcting the blurring of the photographic image accompanied by the vibration of the aforementioned lens, achieving clear imaging under vibration conditions, and the second lens group is small in size, which helps to reduce the burden on the drive system.

[0024] According to one aspect of the present invention, the third lens group is movable along the optical axis, and its main function is to achieve a clear image by changing the image plane position during different object distances, correct the aberrations of the system, and help to share the refractive index and optical power of the anti-vibration lens group, preventing an increase in the burden on the drive system. The fourth lens group helps to balance the performance of the focusing group, correct the aberrations of the system, and at the same time reduce tolerance sensitivity and a smaller image-side principal ray angle, ensuring the uniformity of the image.

[0025] According to one aspect of the present invention, the second lens group includes a seventh lens with negative optical power. The seventh lens is a convex-concave lens, which helps the second lens group to achieve image stabilization. Furthermore, the use of a negative lens for image stabilization also helps to reduce the burden on the drive device system.

[0026] According to one aspect of the present invention, the third lens group includes an eighth lens with positive optical power. The eighth lens is a convex-concave lens, which helps to share the refractive index and optical power of the anti-vibration lens group and prevents the drive system from being overburdened.

[0027] According to one aspect of the present invention, the fourth lens group includes a ninth lens with negative optical power and a tenth lens with positive optical power. This is beneficial for balancing the performance of the focusing group, correcting system aberrations, reducing tolerance sensitivity, and obtaining a smaller image-side principal ray angle, thus ensuring image uniformity. The ninth lens is a convex-concave or concave-concave lens, and the tenth lens is a convex-convex or convex-concave lens. In this way, by using cemented sheets appropriately, spherical aberration, chromatic aberration, and astigmatism can be effectively corrected, while also facilitating high and low temperature performance correction, ensuring sufficient back focus, and preventing deterioration of focusing performance.

[0028] According to one aspect of the present invention, by rationally setting the relationship between the focal length of the second lens group and the focal length of the imaging system, it is beneficial for the second lens group to achieve its image stabilization function. Similarly, by rationally setting the relationship between the focal length of the imaging system and the focal length of the third lens group, it is beneficial for the third lens group to achieve its focusing function.

[0029] According to one aspect of the present invention, by rationally setting the distance from the aperture stop to the second lens, system aberrations can be effectively reduced, while simultaneously sharing the aberrations of the focus group, thereby improving the image quality of the entire system. By rationally setting the relationship between the total length of the imaging system and the focal length of the imaging system, aberrations generated by the focus group can be effectively reduced, while simultaneously sharing the aberrations of the remaining groups, thereby improving the image quality of the entire system, ensuring sufficient back focus, and preventing scaling. By rationally setting the relationship between the back focus of the imaging system and the focal length of the imaging system, aberrations generated by the focus group can be effectively reduced, while simultaneously sharing the aberrations of the remaining groups, thereby improving the image quality of the entire system and ensuring sufficient back focus.

[0030] According to one aspect of the present invention, by reasonably setting the refractive index and Abbe number of the second lens, it is beneficial to correct chromatic aberration and high and low temperatures, while reducing infrared defocus and improving the resolution of visible and infrared light. Attached Figure Description

[0031] Figure 1 , Figure 2 and Figure 3 The diagrams schematically illustrate the lens structure, positive image stabilization lens structure, and negative image stabilization lens structure when the object distance is infinitely far according to the first embodiment of the present invention.

[0032] Figure 4 and Figure 5 The MTF diagram and transverse chromatic aberration diagram of the lens in the first embodiment of the present invention are schematically shown respectively when the object distance is infinite.

[0033] Figure 6 and Figure 7 The MTF diagram and lateral chromatic aberration diagram of the positive image stabilization lens of the first embodiment of the present invention at an infinite object distance are schematically shown respectively.

[0034] Figure 8 and Figure 9 The MTF diagram and lateral chromatic aberration diagram of the negative image stabilization lens of the first embodiment of the present invention are schematically shown respectively when the object distance is infinite.

[0035] Figure 10 , Figure 11 and Figure 12 The diagrams schematically illustrate the lens structure, positive image stabilization lens structure, and negative image stabilization lens structure when the object distance is infinitely far according to the second embodiment of the present invention.

[0036] Figure 13 and Figure 14 The MTF diagram and lateral chromatic aberration diagram of the lens when the object distance is infinitely far according to the second embodiment of the present invention are shown schematically.

[0037] Figure 15 and Figure 16 The MTF diagram and lateral chromatic aberration diagram of the positive image stabilization lens of the second embodiment of the present invention at an infinity object distance are schematically shown respectively.

[0038] Figure 17 and Figure 18 The MTF diagram and lateral chromatic aberration diagram of the negative image stabilization lens of the second embodiment of the present invention are schematically shown respectively when the object distance is infinite.

[0039] Figure 19 , Figure 20 and Figure 21 The diagrams schematically illustrate the lens structure, positive image stabilization lens structure, and negative image stabilization lens structure when the object distance is infinitely far according to the third embodiment of the present invention.

[0040] Figure 22 and Figure 23 The MTF diagram and lateral chromatic aberration diagram of the lens when the object distance is infinitely far according to the third embodiment of the present invention are shown schematically.

[0041] Figure 24 and Figure 25 The MTF diagram and lateral chromatic aberration diagram of the positive image stabilization lens of the third embodiment of the present invention are schematically shown respectively when the object distance is infinitely far.

[0042] Figure 26 and Figure 27 The MTF diagram and lateral chromatic aberration diagram of the negative image stabilization lens in the third embodiment of the present invention are schematically shown respectively when the object distance is infinitely far.

[0043] Figure 28 , Figure 29 and Figure 30 The diagrams schematically illustrate the lens structure, positive image stabilization lens structure, and negative image stabilization lens structure when the object distance is infinitely far according to the fourth embodiment of the present invention.

[0044] Figure 31 and Figure 32 The MTF diagram and lateral chromatic aberration diagram of the lens when the object distance is infinitely far according to the fourth embodiment of the present invention are shown schematically.

[0045] Figure 33 and Figure 34 The MTF diagram and lateral chromatic aberration diagram of the positive image stabilization lens of the fourth embodiment of the present invention at an infinite object distance are schematically shown respectively.

[0046] Figure 35 and Figure 36 The MTF chart and lateral chromatic aberration chart of the negative image stabilization lens in the fourth embodiment of the present invention are schematically shown respectively when the object distance is infinite. Detailed Implementation

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0048] When describing embodiments of the present invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" express orientations or positional relationships based on the orientations or positional relationships shown in the relevant drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not 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, the above terms should not be construed as limitations on the present invention.

[0049] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described in detail here, but the embodiments of the present invention are not limited to the following embodiments.

[0050] See Figure 1The optical image-stabilized telephoto lens of the present invention includes a first lens group G1, a second lens group G2, a third lens group G3, and a fourth lens group G4 arranged sequentially along the optical axis from the object side to the image side. The third lens group G3 can move along the optical axis to achieve image plane position changes during different object distances, thereby obtaining a clear image; the second lens group G2 can move in a direction perpendicular to the optical axis to correct the blurring of the photographic image accompanied by the aforementioned lens vibration, thereby achieving clear imaging under vibration conditions. In the present invention, the first lens group G1 has positive optical power, the second lens group G2 has negative optical power, the third lens group G3 has positive optical power, and the fourth lens group G4 has negative optical power.

[0051] In this invention, the first lens group G1 includes a first lens L1 with positive optical power, an aperture stop STO, a second lens L2 with positive optical power, a third lens L3 with positive or negative optical power, a fourth lens L4 with positive or negative optical power, a fifth lens L5 with positive or negative optical power, and a sixth lens L6 with positive or negative optical power, arranged sequentially along the optical axis from the object side to the image side. Thus, by using a reasonable combination of positive and negative optical powers of the lenses, the imaging light can be collected effectively, which is beneficial for correcting spherical aberration, chromatic aberration, astigmatism, and high / low temperature performance within the first lens group G1. At the same time, it can also reduce intra-group tolerance sensitivity and ensure image uniformity.

[0052] In this invention, the first lens L1 is a convex-concave lens, the second lens L2 is a convex-convex lens, the third lens L3 is a concave-concave or convex-convex lens, the fourth lens L4 is a convex-convex, concave-concave, or convex-flat lens, the fifth lens L5 is a concave-concave, convex-concave, or convex-convex lens, and the sixth lens L6 is a convex-concave or concave-concave lens. Thus, the appropriate combination of positive and negative lenses facilitates the collection of imaging light, achieves large-aperture imaging, and effectively corrects spherical aberration and astigmatism, while also providing good performance at high and low temperatures.

[0053] In this invention, at least one cemented lens group is formed by combining the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6. By using cemented lenses appropriately, chromatic aberration, spherical aberration, and temperature performance can be significantly corrected, while tolerance sensitivity is easily maintained. By using a negative refractive power lens to reduce the refractive power of a positive lens, the lens can better achieve full-frame imaging with a large image plane and a smaller principal ray incident angle, resulting in better color reproduction.

[0054] In this invention, the second lens group G2 includes a seventh lens L7 with negative optical power. This allows the second lens group G2 to move in a direction perpendicular to the optical axis, thereby correcting blur in the photographic image caused by lens vibration and achieving clear imaging even under vibration. Furthermore, the small size of the second lens group G2 helps reduce the burden on the drive system. The seventh lens L7 is a convex-concave lens; using a negative lens for image stabilization further reduces the burden on the drive system.

[0055] In this invention, the third lens group G3 includes an eighth lens L8 with positive optical power. Thus, the third lens group G3 can achieve a clear image despite changes in image plane position at different object distances, correct system aberrations, and also help to share the refractive index and optical power of the anti-vibration group (i.e., the second lens group G2), preventing increased load on the drive system. Since telephoto lenses are not sensitive to field curvature, only a positive optical power lens affecting the back focus needs to be selected for focusing. The eighth lens L8 is a convex-concave lens, thereby preventing increased load on the drive system.

[0056] In this invention, the fourth lens group G4 includes a ninth lens L9 with negative optical power and a tenth lens L10 with positive optical power, arranged sequentially along the optical axis from the object side to the image side. The fourth lens group G4 helps balance the performance of the focusing group, correct system aberrations, reduce tolerance sensitivity, and achieve a smaller image-side principal ray angle, ensuring image uniformity. The ninth lens L9 is a convex-concave or concave-concave lens, and the tenth lens L10 is a convex-convex or convex-concave lens. Thus, by using cemented sheets appropriately, spherical aberration, chromatic aberration, and astigmatism can be effectively corrected, while also facilitating high and low temperature performance correction, ensuring sufficient back focus, and preventing degradation of focusing performance.

[0057] In this invention, the focal length F2 of the second lens group G2 and the focal length F of the telephoto lens satisfy the following relationship: -0.2 ≤ F2 / F ≤ -0.15. Satisfying this condition facilitates the second lens group G2 in achieving its anti-vibration function. The focal length F of the telephoto lens and the focal length F3 of the third lens group G3 satisfy the following relationship: 0.15 ≤ F3 / F ≤ 0.35. Satisfying this condition facilitates the third lens group G3 in achieving its focusing function through movement.

[0058] In this invention, the distance d1 from the aperture stop STO to the second lens L2 satisfies the following condition: 30 ≤ d1 ≤ 85. If the distance is less than the lower limit of the above relationship, the system aberration balance will be limited, resolving power will be difficult to improve, and the lens aperture will be too large, thus drastically increasing costs. If the distance is greater than the upper limit of the above relationship, it is detrimental to high and low temperature conditions and image quality balance. Therefore, satisfying the above relationship can effectively reduce system aberrations, while simultaneously sharing the aberrations of the focus group, thus improving the overall image quality of the system.

[0059] In this invention, the total length L of the telephoto lens and the focal length F of the telephoto lens satisfy the following relationship: 0.5 ≤ L / F ≤ 0.8. Satisfying this relationship can effectively reduce the aberrations generated by the focus group, while also sharing the aberrations of other groups, improving the image quality of the entire system, ensuring sufficient back focus, and preventing scaling.

[0060] In this invention, the refractive index Nd of the second lens L2 is... L2 And Abbe number Vd L2 Each of the following conditions must be met: 1.4 ≤ NdL2 ≤1.6; 60≤Vd L2 ≤90. Satisfying the above relationship is beneficial for color difference and high and low temperature correction. At the same time, it can reduce infrared defocus and improve the resolution of visible and infrared light.

[0061] In this invention, the back focus (BF) of the telephoto lens and the focal length (F) of the telephoto lens satisfy the following relationship: 0.005 ≤ BF / F ≤ 0.042. Satisfying this relationship can effectively reduce aberrations generated by the focus group, while also sharing the aberrations of other groups, improving the image quality of the entire system, and ensuring sufficient back focus.

[0062] In summary, this invention employs an all-glass structure with a rational distribution of aberrant dispersion glass and high-refractive-index glass to achieve high-quality imaging. It features a long focal length, low load on the vibration-damping drive system, and low cost. Furthermore, the invention rationally combines positive and negative power lenses, enabling high image quality at various object distances and facilitating temperature drift correction at high and low temperatures. A negative power lens is used in the telephoto lens, moving perpendicular to the optical axis to correct for blurring caused by vibration of the fixed-focus lens, achieving clear imaging even under vibration and significantly reducing the weight and cost of the vibration-damping drive system. Moreover, the invention rationally utilizes cemented lenses, which helps correct chromatic aberration and spherical aberration throughout the optical system, ensuring confocal focus for visible and infrared light.

[0063] The telephoto lens of the present invention will be described in detail below with four sets of embodiments. In the following embodiments, Sur1, Sur2, ..., SurN are used to represent the surfaces of each lens, the aperture stop is denoted as STOP, the cemented surface of the cemented lens group is denoted as one surface, and the image surface is denoted as Image.

[0064] The parameters for each implementation method that meets the above conditions are shown in Table 1 below:

[0065]

[0066]

[0067] Table 1

[0068] First implementation method

[0069] See Figures 1 to 3 In this embodiment, the second lens L2, the third lens L3, and the fourth lens L4 are cemented together to form a cemented triplet lens group, and the fifth lens L5 and the sixth lens L6 are cemented together to form a cemented doublet lens group. TTL = 349.5441 mm; FNO = 6; focal length F = 500 mm. The refractive index Nd of the second lens L2 is... L2 And Abbe number Vd L2 They are: Nd L2 =1.40; VdL2 =81.6. The optical power of the third lens L3 is negative, the optical power of the fourth lens L4 is positive, the optical power of the fifth lens L5 is negative, and the optical power of the sixth lens L6 is positive.

[0070] The parameters of each lens in the telephoto lens of this embodiment are shown in Table 2 below:

[0071]

[0072]

[0073] Table 2

[0074] Combination Figures 4 to 9 As can be seen, the telephoto lens of this embodiment uses an all-glass structure, with a reasonable distribution of aberrant dispersion glass and high refractive index glass, to achieve high-quality imaging. It has the advantages of long focal length, low load on the anti-vibration drive system, and low cost, enabling high image quality performance at different object distances. It is also beneficial for temperature drift correction at high and low temperatures and ensures confocality of visible light and infrared light. By using a lens with negative optical power that moves in a direction perpendicular to the optical axis, the blurring of the photographic image accompanied by the vibration of the aforementioned fixed focal length lens is corrected, achieving clear imaging under vibration conditions and greatly reducing the weight and cost of the anti-vibration drive system.

[0075] Second implementation method

[0076] See Figures 10 to 12 In this embodiment, the second lens L2, the third lens L3, and the fourth lens L4 are cemented together to form a cemented triplet lens group. TTL = 345.36 mm; FNO = 6; focal length F = 500 mm. The refractive index Nd of the second lens L2 is... L2 And Abbe number Vd L2 For: Nd L2 =1.52; Vd L2 =69.7. The optical power of the third lens L3 is negative, the optical power of the fourth lens L4 is positive, the optical power of the fifth lens L5 is negative, and the optical power of the sixth lens L6 is positive.

[0077] The parameters of each lens in the telephoto lens of this embodiment are shown in Table 3 below:

[0078] Surface Type Radius Thickness nd vd Sur1 standard 187.958 7.3 1.760 22.7 Sur2 standard 2020.919 19.54 Stop standard Infinity 64.56 Sur4 standard 220.03 6.84 1.52 69.7 Sur5 standard -192.448 2 1.8 22.7 Sur6 standard 66.866 8.61 1.55 67.2 Sur7 standard Infinity 1.2 Sur8 standard 172.002 2 1.48 60 Sur9 standard 81.485 8.82 Sur10 standard 71.857 15 1.80 27.7 Sur11 standard 131.543 136.06 Sur12 standard 217.584 2 1.53 54.5 Sur13 standard 46.477 12.06 (Articulated) Sur14 standard 56.505 8.75 1.61 25.7 Sur15 standard 147.118 20.37 (Articulated) Sur16 standard 2351.77 2 1.75 52.3 Sur17 standard 15.013 1.02 Sur18 standard 16.221 6.49 1.86 26.5 Sur19 standard 110.635 20.74 Image standard Infinity

[0079] Table 3

[0080] Combination Figures 13 to 18As can be seen, the telephoto lens of this embodiment uses an all-glass structure, with a reasonable distribution of aberrant dispersion glass and high refractive index glass, to achieve high-quality imaging. It has the advantages of long focal length, low load on the anti-vibration drive system, and low cost, enabling high image quality performance at different object distances. It is also beneficial for temperature drift correction at high and low temperatures and ensures confocality of visible light and infrared light. By using a lens with negative optical power that moves in a direction perpendicular to the optical axis, the blurring of the photographic image accompanied by the vibration of the aforementioned fixed focal length lens is corrected, achieving clear imaging under vibration conditions and greatly reducing the weight and cost of the anti-vibration drive system.

[0081] Third implementation method

[0082] See Figures 19 to 21 In this embodiment, the third lens L3 and the fourth lens L4 are cemented together to form a cemented doublet, and the fifth lens L5 and the sixth lens L6 are cemented together to form a cemented doublet. TTL = 336.8 mm; FNO = 6; focal length F = 500 mm. The refractive index Nd of the second lens L2 is... L2 And Abbe number Vd L2 They are: Nd L2 =1.58; Vd L2 =65.62. The optical power of the third lens L3 is negative, the optical power of the fourth lens L4 is positive, the optical power of the fifth lens L5 is negative, and the optical power of the sixth lens L6 is positive.

[0083] The parameters of each lens in the telephoto lens of this embodiment are shown in Table 4 below:

[0084]

[0085]

[0086] Table 4

[0087] Combination Figures 22 to 27 As can be seen, the telephoto lens of this embodiment uses an all-glass structure, with a reasonable distribution of aberrant dispersion glass and high refractive index glass, to achieve high-quality imaging. It has the advantages of long focal length, low load on the anti-vibration drive system, and low cost, enabling high image quality performance at different object distances. It is also beneficial for temperature drift correction at high and low temperatures and ensures confocality of visible light and infrared light. By using a lens with negative optical power that moves in a direction perpendicular to the optical axis, the blurring of the photographic image accompanied by the vibration of the aforementioned fixed focal length lens is corrected, achieving clear imaging under vibration conditions and greatly reducing the weight and cost of the anti-vibration drive system.

[0088] Fourth implementation method

[0089] See Figures 28 to 30In this embodiment, the third lens L3 and the fourth lens L4 are cemented together to form a cemented doublet, and the fifth lens L5 and the sixth lens L6 are cemented together to form a cemented doublet. TTL = 303.85mm; FNO = 6; focal length F = 500mm. The refractive index Nd of the second lens L2 is... L2 And Abbe number Vd L2 They are: Nd L2 =1.59; Vd L2 =75.6. The optical power of the third lens L3 is positive, the optical power of the fourth lens L4 is negative, the optical power of the fifth lens L5 is positive, and the optical power of the sixth lens L6 is negative.

[0090] The parameters of each lens in the telephoto lens of this embodiment are shown in Table 5 below:

[0091]

[0092]

[0093] Table 5

[0094] Combination Figures 31 to 36 As can be seen, the telephoto lens of this embodiment uses an all-glass structure, with a reasonable distribution of aberrant dispersion glass and high refractive index glass, to achieve high-quality imaging. It has the advantages of long focal length, low load on the anti-vibration drive system, and low cost, enabling high image quality performance at different object distances. It is also beneficial for temperature drift correction at high and low temperatures and ensures confocality of visible light and infrared light. By using a lens with negative optical power that moves in a direction perpendicular to the optical axis, the blurring of the photographic image accompanied by the vibration of the aforementioned fixed focal length lens is corrected, achieving clear imaging under vibration conditions and greatly reducing the weight and cost of the anti-vibration drive system.

[0095] The above description is merely one embodiment of the present invention and is not intended to limit the invention. Those skilled in the art will recognize that the present invention can be modified and varied in various ways. Any modifications, equivalent substitutions, or improvements 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 telephoto lens comprising a first lens group (G1), a second lens group (G2), a third lens group (G3), and a fourth lens group (G4) arranged sequentially along the optical axis from the object side to the image side, for a total of four lens groups, wherein the third lens group (G3) is movable along the optical axis, and the second lens group (G2) is movable in a direction perpendicular to the optical axis, characterized in that... The first lens group (G1) has positive optical power, the second lens group (G2) has negative optical power, the third lens group (G3) has positive optical power, and the fourth lens group (G4) has negative optical power. The first lens group (G1) includes a first lens (L1) with positive optical power, a second lens (L2) with positive optical power, a third lens (L3) with positive or negative optical power, a fourth lens (L4) with positive or negative optical power, a fifth lens (L5) with positive or negative optical power, and a sixth lens (L6) with positive or negative optical power, arranged sequentially along the optical axis from the object side to the image side, for a total of six lenses with optical power; The second lens group (G2) includes a seventh lens (L7) with negative optical power, and there is a total of one lens with optical power; The third lens group (G3) includes an eighth lens (L8) with positive optical power, and there is a total of one lens with optical power; The fourth lens group (G4) includes a ninth lens (L9) with negative optical power and a tenth lens (L10) with positive optical power, arranged sequentially along the optical axis from the object side to the image side, for a total of two lenses with optical power.

2. The telephoto lens according to claim 1, characterized in that, An aperture stop (STO) is provided between the first lens (L1) and the second lens (L2).

3. The telephoto lens according to claim 2, characterized in that, The first lens (L1) is a convex-concave lens, the second lens (L2) is a convex-convex lens, the third lens (L3) is a concave-concave or convex-convex lens, the fourth lens (L4) is a convex-convex, concave-concave, or convex-flat lens, the fifth lens (L5) is a concave-concave, convex-concave, or convex-convex lens, and the sixth lens (L6) is a convex-concave or concave-concave lens.

4. The telephoto lens according to claim 2, characterized in that, The second lens (L2), the third lens (L3), the fourth lens (L4), the fifth lens (L5), and the sixth lens (L6) are combined to form at least one cemented lens group.

5. The telephoto lens according to claim 1, characterized in that, The seventh lens (L7) is a convex-concave lens.

6. The telephoto lens according to claim 1, characterized in that, The eighth lens (L8) is a convex-concave lens.

7. The telephoto lens according to claim 1, characterized in that, The ninth lens (L9) is a convex-concave or concave-concave lens, and the tenth lens (L10) is a convex-convex or convex-concave lens.

8. The telephoto lens according to any one of claims 1-7, characterized in that, The focal length F2 of the second lens group (G2) and the focal length F of the telephoto lens satisfy the following relationship: -0.2≤F2 / F≤-0.

15.

9. The telephoto lens according to any one of claims 1-7, characterized in that, The focal length F of the telephoto lens and the focal length F3 of the third lens group (G3) satisfy the following relationship: 0.15≤F3 / F≤0.

35.

10. The telephoto lens according to claim 2, characterized in that, The distance d1 from the aperture stop (STO) to the second lens (L2) satisfies the following condition: 30≤d1≤85.

11. The telephoto lens according to any one of claims 1-7, characterized in that, The total length L of the telephoto lens and the focal length F of the telephoto lens satisfy the following relationship: 0.5≤L / F≤0.

8.

12. The telephoto lens according to claim 1, characterized in that, The refractive index Nd of the second lens (L2) L2 And Abbe number Vd L2 Each of the following conditions must be met: 1.4 ≤ Nd L2 ≤1.6; 60≤Vd L2 ≤90.

13. The telephoto lens according to any one of claims 1-7, characterized in that, The rear focal length BF of the telephoto lens and the focal length F of the telephoto lens satisfy the following relationship: 0.005≤BF / F≤0.042.

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