Zoom lens and monitoring camera
By designing a zoom lens with a combination of 12 lenses, employing a negative optical power focusing lens group, a positive optical power zoom lens group, and a positive optical power fixed lens group, a miniaturized and low-cost zoom lens is achieved. It is suitable for consumer electronics and security monitoring, and has good imaging quality and imaging capabilities in low light.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- UNION OPTECH
- Filing Date
- 2026-03-11
- Publication Date
- 2026-04-24
AI Technical Summary
The zoom lenses used in mainstream high-resolution surveillance systems are large and expensive, failing to meet market demand.
Design a zoom lens comprising 12 lenses, with a focal length adjustable from 4.5mm to 36mm through a combination of a negative focal power focusing lens group, a positive focal power zoom lens group, and a positive focal power fixed lens group, and a total optical length of less than 90mm. It employs an aperture stop to precisely control the amount of light transmitted, and matches the Abbe number and refractive index of the lenses to suppress chromatic aberration.
It achieves miniaturized and low-cost zoom lenses, suitable for consumer electronics and security monitoring, with good image quality and low-light imaging capabilities, overcoming the shortcomings of large and expensive lenses.
Smart Images
Figure CN121918281A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of zoom lens technology, and particularly to a zoom lens and a surveillance camera. Background Technology
[0002] Currently, mainstream high-resolution surveillance system zoom lenses on the market suffer from drawbacks such as large size and high cost, failing to meet market demands. Summary of the Invention
[0003] The main objective of this invention is to provide a zoom lens and a surveillance camera, aiming to offer a zoom lens that is small in size and low in cost.
[0004] To achieve the above objectives, the present invention proposes a zoom lens comprising a focusing lens group, a zoom lens group, and a fixed lens group arranged sequentially along the optical axis from the object plane to the image plane.
[0005] The focusing lens group is movably disposed along the optical axis for focusing, the zoom lens group is movably disposed along the optical axis for zooming, and the fixed lens group is fixedly disposed. The focusing lens group has negative optical power, the zoom lens group has positive optical power, and the fixed lens group has positive optical power; The focusing lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially from the object plane to the image plane; The zoom lens group includes a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, and an eleventh lens arranged sequentially from the object plane to the image plane; The fixed lens group includes a twelfth lens; The focal length of the zoom lens is adjustable within a range of 4.5mm or greater and 36mm or less, and the total optical length of the zoom lens is TTL, where TTL ≤ 90mm.
[0006] In one embodiment, the first lens has negative optical power, the second lens has negative optical power, the third lens has positive optical power, and the fourth lens has negative optical power; The fifth lens has positive optical power, the sixth lens has negative optical power, the seventh lens has positive optical power, the eighth lens has negative optical power, the ninth lens has positive optical power, the tenth lens has negative optical power, and the eleventh lens has positive optical power. The twelfth lens has positive optical power.
[0007] In one embodiment, the zoom lens is in a wide-angle state with a focal length of F; The focal length of the focusing lens group is f1, -0.6≤F / f1≤-0.1; The focal length of the zoom lens group is f2, 0.1≤F / f2≤0.5; The focal length of the fixed lens group is f3, -0.1≤F / f3≤0.3.
[0008] In one implementation, The focal length of the first lens is f11, and 0.52 ≤ f1 / f11 ≤ 0.70; The focal length of the second lens is f12, and 0.21 ≤ f1 / f12 ≤ 0.29; The focal length of the third lens is f13, and -0.16 ≤ f1 / f13 ≤ -0.12; The focal length of the fourth lens is f14, and 0.15 ≤ f1 / f14 ≤ 0.20; The focal length of the fifth lens is f21, and 0.81≤f2 / f21≤1.10; The focal length of the sixth lens is f22, -1.60≤f2 / f22≤-1.18; The focal length of the seventh lens is f23, and 1.42≤f2 / f23≤1.93; The focal length of the eighth lens is f24, -0.14≤f2 / f24≤-0.10; The focal length of the ninth lens is f25, and 0.49≤f2 / f25≤0.66; The focal length of the tenth lens is f26, and -1.75≤f2 / f26≤-1.29; The focal length of the eleventh lens is f27, and 0.25≤f2 / f27≤0.33; The focal length of the twelfth lens is f31, and 0.85≤f3 / f31≤1.15.
[0009] In one embodiment, the target diameter of the zoom lens is less than or equal to 9.2 mm.
[0010] In one embodiment, the second lens and the third lens are cemented together, the sixth lens and the seventh lens are cemented together, and the ninth lens and the tenth lens are cemented together.
[0011] In one embodiment, the zoom lens further includes an aperture stop located between the fifth lens and the sixth lens.
[0012] In one embodiment, the Abbe number of the first lens is V1, where 58.014 ≤ V1 ≤ 59.186; The Abbe number of the second lens is V2, 80.784≤V2≤82.416; The Abbe number of the third lens is V3, and 17.721≤V3≤18.079; The Abbe number of the fourth lens is V4, where 60.588 ≤ V4 ≤ 61.812; The Abbe number of the fifth lens is V5, where 80.784 ≤ V5 ≤ 82.416; The Abbe number of the sixth lens is V6, 57.816≤V6≤58.984; The Abbe number of the seventh lens is V7, where 80.784 ≤ V7 ≤ 82.416; The Abbe number of the eighth lens is V8, where 55.044 ≤ V8 ≤ 56.156; The Abbe number of the ninth lens is V9, and 60.588≤V9≤61.812; The Abbe number of the tenth lens is V10, 51.777≤V10≤52.823; The Abbe number of the eleventh lens is V11, 55.044≤V11≤56.156; The Abbe number of the twelfth lens is V12, where 55.044 ≤ V12 ≤ 56.156.
[0013] In one embodiment, the refractive index of the first lens is N1, where 1.608 ≤ N1 ≤ 1.612; The refractive index of the second lens is N2, 1.499≤N2≤1.502; The refractive index of the third lens is N3, 1.948≤N3≤1.952; The refractive index of the fourth lens is N4, where 1.588 ≤ N4 ≤ 1.592; The refractive index of the fifth lens is N5, where 1.499 ≤ N5 ≤ 1.502; The refractive index of the sixth lens is N6, where 1.648 ≤ N6 ≤ 1.652; The refractive index of the seventh lens is N7, where 1.499 ≤ N7 ≤ 1.502; The refractive index of the eighth lens is N8, where 1.538 ≤ N8 ≤ 1.542; The refractive index of the ninth lens is N9, where 1.588 ≤ N9 ≤ 1.592; The refractive index of the tenth lens is N10, 1.758≤N10≤1.762; The refractive index of the eleventh lens is N11, 1.538≤N11≤1.542; The refractive index of the twelfth lens is N12, where 1.538 ≤ N12 ≤ 1.542.
[0014] The present invention also proposes a surveillance camera, including a zoom lens, which includes a focusing lens group, a zoom lens group and a fixed lens group arranged sequentially along the optical axis from the object plane to the image plane. The focusing lens group is movably disposed along the optical axis for focusing, the zoom lens group is movably disposed along the optical axis for zooming, and the fixed lens group is fixedly disposed. The focusing lens group has negative optical power, the zoom lens group has positive optical power, and the fixed lens group has positive optical power; The focusing lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially from the object plane to the image plane; The zoom lens group includes a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, and an eleventh lens arranged sequentially from the object plane to the image plane; The fixed lens group includes a twelfth lens; The focal length of the zoom lens is adjustable within a range of 4.5mm or greater and 36mm or less, and the total optical length of the zoom lens is TTL, where TTL ≤ 90mm.
[0015] The technical solution of this invention achieves the technical effects of zoom, small size, and low cost by setting twelve lenses. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.
[0017] Figure 1 A schematic diagram of a structure of an embodiment of the zoom lens provided by the present invention; Figure 2 for Figure 1 Transverse chromatic aberration diagram of a medium zoom lens in wide-angle mode; Figure 3 for Figure 1 Vertical chromatic aberration diagram of a medium zoom lens in telephoto mode.
[0018] Explanation of icon numbers: 100. Zoom lens; 1. Focusing lens group; 11. First lens; 12. Second lens; 13. Third lens; 14. Fourth lens; 2. Zoom lens group; 21. Fifth lens; 22. Sixth lens; 23. Seventh lens; 24. Eighth lens; 25. Ninth lens; 26. Tenth lens; 27. Eleventh lens; 3. Fixed lens group; 31. Twelfth lens; 4. Aperture stop; 5. Filter; 6. Image plane.
[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0021] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.
[0022] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.
[0023] Currently, mainstream high-resolution surveillance system zoom lenses on the market suffer from drawbacks such as large size and high cost, failing to meet market demands.
[0024] This invention proposes a zoom lens.
[0025] Please see Figure 1In one embodiment of the present invention, the zoom lens 100 includes a focusing lens group 1, a zoom lens group 2, and a fixed lens group 3 arranged sequentially along the optical axis from the object plane to the image plane 6; the focusing lens group 1 is movably disposed along the optical axis for focusing, the zoom lens group 2 is movably disposed along the optical axis for zooming, and the fixed lens group 3 is fixedly disposed; the focusing lens group 1 has negative optical power, the zoom lens group 2 has positive optical power, and the fixed lens group 3 has positive optical power; the focusing lens group 1 includes a focusing lens group 1, a zoom lens group 2, and a fixed lens group 3 arranged sequentially from the object plane to the image plane 6. The zoom lens group 2 includes a first lens 11, a second lens 12, a third lens 13, and a fourth lens 14; the zoom lens group 2 includes a fifth lens 21, a sixth lens 22, a seventh lens 23, an eighth lens 24, a ninth lens 25, a tenth lens 26, and an eleventh lens 27 arranged sequentially from the object plane to the image plane 6; the fixed lens group 3 includes a twelfth lens 31; wherein, the focal length of the zoom lens 100 is adjustable within a range of greater than or equal to 4.5 mm and less than or equal to 36 mm, and the total optical length of the zoom lens 100 is TTL, where TTL≤90 mm.
[0026] The technical solution of this invention employs 11 movable lenses and 1 fixed lens, totaling 12 lenses. This fewer lens count reduces assembly difficulty, as well as the overall optical assembly and cost. Focusing is achieved through a negative optical power focusing group, a positive optical power zoom group, and a positive optical power fixed group, resulting in optimized image quality. The overall focal length covers 4.5mm-36mm, with a TTL ≤ 90mm, balancing miniaturization and low cost, making it suitable for consumer electronics, security monitoring, and other applications.
[0027] To achieve the goal that "the focusing lens group 1 has negative optical power, the zoom lens group 2 has positive optical power, and the fixed lens group 3 has positive optical power," each lens is further designed as follows: The first lens 11 has negative optical power and can be used for primary distortion correction at the wide-angle end, serving as the basis for the negative optical power of the focusing lens group 1. The second lens 12 has negative optical power and can be used to enhance the total negative optical power and compensate for the spherical aberration of the first lens 11. The third lens 13 has positive optical power and can be used to correct chromatic aberration within the focusing lens group 1 and balance negative optical power aberrations. The fourth lens 14 has negative optical power and can be used to finalize the total negative optical power of the focusing group.
[0028] The fifth lens 21 has positive optical power and can be used as the basis for the optical power of the zoom lens group 2. The sixth lens 22 has negative optical power and can be used to counteract the chromatic aberration of the fifth lens 21 and assist in adjusting the zoom optical power. The seventh lens 23 has positive optical power and can be used to enhance positive optical power and correct image plane shift at the wide-angle end. The eighth lens 24 has negative optical power and can be used to correct spherical aberration at the telephoto end and balance the aberrations of the zoom lens group 2. The ninth lens 25 has positive optical power and can be used to supplement positive optical power to ensure that the focal length at the telephoto end meets the standard. The tenth lens 26 has negative optical power and can be used to counteract the residual chromatic aberration of the ninth lens 25 and optimize the imaging consistency across the entire focal length. The eleventh lens 27 has positive optical power and can be used to fix the total positive optical power of the zoom group to ensure image plane stability. The twelfth lens 31 has positive optical power and can be used to correct residual chromatic aberration and field curvature across the entire focal length, ultimately focusing the light rays onto the image plane 6.
[0029] The specific design of the zoom lens 100 regarding focal length is as follows: The zoom lens 100 is in wide-angle mode with a focal length of F; the focal length of the focusing lens group 1 is f1, -0.6≤F / f1≤-0.1; the focal length of the zoom lens group 2 is f2, 0.1≤F / f2≤0.5; and the focal length of the fixed lens group 3 is f3, -0.1≤F / f3≤0.3. The focal lengths f1 (focusing group), f2 (zoom group), and f3 (fixed group) of the three lens groups are calculated based on proportional constraints, taking into account both the rationality of optical power and the control of aberration correction space and volume.
[0030] Specifically, the focal length of each lens satisfies the following conditions: the focal length of the first lens 11 is f11, 0.52≤f1 / f11≤0.70; the focal length of the second lens 12 is f12, 0.21≤f1 / f12≤0.29; the focal length of the third lens 13 is f13, -0.16≤f1 / f13≤-0.12; the focal length of the fourth lens 14 is f14, 0.15≤f1 / f14≤0.20; the focal length of the fifth lens 21 is f21, 0.81≤f2 / f21≤1.10; and the focal length of the sixth lens 22 is f22, -1.60≤f2 / f22≤- 1.18; The focal length of the seventh lens 23 is f23, 1.42≤f2 / f23≤1.93; The focal length of the eighth lens 24 is f24, -0.14≤f2 / f24≤-0.10; The focal length of the ninth lens 25 is f25, 0.49≤f2 / f25≤0.66; The focal length of the tenth lens 26 is f26, -1.75≤f2 / f26≤-1.29; The focal length of the eleventh lens 27 is f27, 0.25≤f2 / f27≤0.33; The focal length of the twelfth lens 31 is f31, 0.85≤f3 / f31≤1.15.
[0031] To improve light transmission and ensure good imaging capabilities even in low light conditions, the zoom lens 100 has a target surface diameter of 9.2mm or less. This allows the lens to produce bright, motion-free images in low-light scenarios such as low light, nighttime, and indoor environments without increasing exposure time, thus solving the problem of dark and blurry images at the telephoto end of the small-target-surface zoom lens 100 during nighttime imaging.
[0032] In one embodiment, the second lens 12 and the third lens 13 are cemented together, primarily to correct axial chromatic aberration of the focusing lens group 1 and compensate for field curvature at the wide-angle end of the large target surface. The sixth lens 22 and the seventh lens 23 are cemented together, primarily to correct core chromatic aberration of the zoom lens group 2 and optimize image quality across the entire focal length of the large target surface. The ninth lens 25 and the tenth lens 26 are cemented together, primarily to correct residual chromatic aberration at the telephoto end of the zoom lens group 2 and improve the sharpness of long-distance imaging.
[0033] The zoom lens 100 also includes an aperture stop 4, which is located between the fifth lens 21 and the sixth lens 22. This aperture stop allows for precise control of light transmission and suppression of stray light and glare. Positioned at the core of the zoom lens group 2, the aperture stop 4 precisely matches the effective field of view of the large target surface, preventing overexposure at the edges of the field of view and ensuring uniform exposure across the entire field of view. This solves the problem of "center overexposure and edge underexposure" that often occurs with large target surfaces.
[0034] By combining lenses with different Abbe numbers, efficient chromatic aberration cancellation is achieved. Combined with cemented lenses, precise chromatic aberration suppression across the entire focal length is possible, meeting the edge chromatic aberration correction requirements of a 9.2mm large target surface. Specifically: the Abbe number of the first lens 11 is V1, 58.014≤V1≤59.186; the Abbe number of the second lens 12 is V2, 80.784≤V2≤82.416; the Abbe number of the third lens 13 is V3, 17.721≤V3≤18.079; the Abbe number of the fourth lens 14 is V4, 60.588≤V4≤61.812; the Abbe number of the fifth lens 21 is V5, 80.784≤V5≤82.416; the Abbe number of the sixth lens 22 is V6, 57.816≤V6≤58.984; The Abbe number of the seventh lens 23 is V7, 80.784≤V7≤82.416; the Abbe number of the eighth lens 24 is V8, 55.044≤V8≤56.156; the Abbe number of the ninth lens 25 is V9, 60.588≤V9≤61.812; the Abbe number of the tenth lens 26 is V10, 51.777≤V10≤52.823; the Abbe number of the eleventh lens 27 is V11, 55.044≤V11≤56.156; and the Abbe number of the twelfth lens 31 is V12, 55.044≤V12≤56.156.
[0035] For the refractive indices of each lens: the refractive index of the first lens 11 is N1, 1.608 ≤ N1 ≤ 1.612; the refractive index of the second lens 12 is N2, 1.499 ≤ N2 ≤ 1.502; the refractive index of the third lens 13 is N3, 1.948 ≤ N3 ≤ 1.952; the refractive index of the fourth lens 14 is N4, 1.588 ≤ N4 ≤ 1.592; the refractive index of the fifth lens 21 is N5, 1.499 ≤ N5 ≤ 1.502; and the refractive index of the sixth lens 22 is N6, 1.648 ≤ N6 ≤ 1.652. The refractive index of the seventh lens 23 is N7, 1.499≤N7≤1.502; the refractive index of the eighth lens 24 is N8, 1.538≤N8≤1.542; the refractive index of the ninth lens 25 is N9, 1.588≤N9≤1.592; the refractive index of the tenth lens 26 is N10, 1.758≤N10≤1.762; the refractive index of the eleventh lens 27 is N11, 1.538≤N11≤1.542; and the refractive index of the twelfth lens 31 is N12, 1.538≤N12≤1.542.
[0036] In one type of embodiment ( Figure 2 and Figure 3 (This is a simulation diagram of the embodiment). The specific design parameters of the zoom lens 100 are as follows: Table 1:
[0037] Table 2: Focal length / aperture of zoom lens in different states:
[0038] Table 3: Position of zoom lens 100 in different states:
[0039] Table 4: One design value for the aspheric coefficient in zoom lens 100: The surface profile of an aspherical lens satisfies the formula:
[0040] Where z represents the axial sagitta in the Z direction of the aspherical surface; y represents the height of the aspherical surface; c represents the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k represents the conic coefficient; and the 2nd, 4th, 6th, 8th, 10th, and 12th order terms represent higher-order aspherical coefficients, respectively.
[0041] Table 4:
[0042] This invention also proposes a surveillance camera, which includes a zoom lens 100. The specific structure of the zoom lens 100 is as described in the above embodiments. Since this surveillance camera adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here. The zoom lens 100 includes a focusing lens group 1, a zoom lens group 2, and a fixed lens group 3 arranged sequentially along the optical axis from the object plane to the image plane 6. The focusing lens group 1 is movably configured along the optical axis for focusing, the zoom lens group 2 is movably configured along the optical axis for zooming, and the fixed lens group 3 is fixedly configured. The focusing lens group 1 has negative optical power, the zoom lens group 2 has positive optical power, and the fixed lens group 3 has positive optical power. The focusing lens group 1 includes a first lens 1 arranged sequentially from the object plane to the image plane 6. 1. A second lens 12, a third lens 13, and a fourth lens 14; the zoom lens group 2 includes a fifth lens 21, a sixth lens 22, a seventh lens 23, an eighth lens 24, a ninth lens 25, a tenth lens 26, and an eleventh lens 27 arranged sequentially from the object plane to the image plane 6; the fixed lens group 3 includes a twelfth lens 31; wherein, the focal length of the zoom lens 100 is adjustable within a range of greater than or equal to 4.5 mm and less than or equal to 36 mm, and the total optical length of the zoom lens 100 is TTL, where TTL≤90 mm.
[0043] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.
Claims
1. A zoom lens, characterized in that, It includes a focusing lens group, a zoom lens group, and a fixed lens group arranged sequentially along the optical axis from the object plane to the image plane; The focusing lens group is movably disposed along the optical axis for focusing, the zoom lens group is movably disposed along the optical axis for zooming, and the fixed lens group is fixedly disposed. The focusing lens group has negative optical power, the zoom lens group has positive optical power, and the fixed lens group has positive optical power; The focusing lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially from the object plane to the image plane; The zoom lens group includes a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, and an eleventh lens arranged sequentially from the object plane to the image plane; The fixed lens group includes a twelfth lens; The focal length of the zoom lens is adjustable within a range of 4.5mm or greater and 36mm or less, and the total optical length of the zoom lens is TTL, where TTL ≤ 90mm.
2. The zoom lens as described in claim 1, characterized in that, The first lens has negative optical power, the second lens has negative optical power, the third lens has positive optical power, and the fourth lens has negative optical power; The fifth lens has positive optical power, the sixth lens has negative optical power, the seventh lens has positive optical power, the eighth lens has negative optical power, the ninth lens has positive optical power, the tenth lens has negative optical power, and the eleventh lens has positive optical power. The twelfth lens has positive optical power.
3. The zoom lens as described in claim 2, characterized in that, The zoom lens is in wide-angle mode with a focal length of F; The focal length of the focusing lens group is f1, -0.6≤F / f1≤-0.1; The focal length of the zoom lens group is f2, 0.1≤F / f2≤0.5; The focal length of the fixed lens group is f3, -0.1≤F / f3≤0.
3.
4. The zoom lens as described in claim 3, characterized in that, The focal length of the first lens is f11, and 0.52 ≤ f1 / f11 ≤ 0.70; The focal length of the second lens is f12, and 0.21 ≤ f1 / f12 ≤ 0.29; The focal length of the third lens is f13, and -0.16 ≤ f1 / f13 ≤ -0.12; The focal length of the fourth lens is f14, and 0.15 ≤ f1 / f14 ≤ 0.20; The focal length of the fifth lens is f21, and 0.81≤f2 / f21≤1.10; The focal length of the sixth lens is f22, -1.60≤f2 / f22≤-1.18; The focal length of the seventh lens is f23, and 1.42≤f2 / f23≤1.93; The focal length of the eighth lens is f24, -0.14≤f2 / f24≤-0.10; The focal length of the ninth lens is f25, and 0.49≤f2 / f25≤0.66; The focal length of the tenth lens is f26, and -1.75≤f2 / f26≤-1.29; The focal length of the eleventh lens is f27, and 0.25≤f2 / f27≤0.33; The focal length of the twelfth lens is f31, and 0.85≤f3 / f31≤1.
15.
5. The zoom lens as described in claim 1, characterized in that, The target diameter of the zoom lens is less than or equal to 9.2 mm.
6. The zoom lens as described in claim 1, characterized in that, The second lens and the third lens are cemented together, the sixth lens and the seventh lens are cemented together, and the ninth lens and the tenth lens are cemented together.
7. The zoom lens as described in claim 1, characterized in that, The zoom lens also includes an aperture stop, which is located between the fifth lens and the sixth lens.
8. The zoom lens as described in claim 1, characterized in that, The Abbe number of the first lens is V1, 58.014≤V1≤59.186; The Abbe number of the second lens is V2, 80.784≤V2≤82.416; The Abbe number of the third lens is V3, and 17.721≤V3≤18.079; The Abbe number of the fourth lens is V4, where 60.588 ≤ V4 ≤ 61.812; The Abbe number of the fifth lens is V5, where 80.784 ≤ V5 ≤ 82.416; The Abbe number of the sixth lens is V6, 57.816≤V6≤58.984; The Abbe number of the seventh lens is V7, where 80.784 ≤ V7 ≤ 82.416; The Abbe number of the eighth lens is V8, where 55.044 ≤ V8 ≤ 56.156; The Abbe number of the ninth lens is V9, and 60.588≤V9≤61.812; The Abbe number of the tenth lens is V10, 51.777≤V10≤52.823; The Abbe number of the eleventh lens is V11, 55.044≤V11≤56.156; The Abbe number of the twelfth lens is V12, where 55.044 ≤ V12 ≤ 56.
156.
9. The zoom lens as described in claim 1, characterized in that, The refractive index of the first lens is N1, where 1.608 ≤ N1 ≤ 1.612; The refractive index of the second lens is N2, 1.499≤N2≤1.502; The refractive index of the third lens is N3, 1.948≤N3≤1.952; The refractive index of the fourth lens is N4, where 1.588 ≤ N4 ≤ 1.592; The refractive index of the fifth lens is N5, where 1.499 ≤ N5 ≤ 1.502; The refractive index of the sixth lens is N6, where 1.648 ≤ N6 ≤ 1.652; The refractive index of the seventh lens is N7, where 1.499 ≤ N7 ≤ 1.502; The refractive index of the eighth lens is N8, where 1.538 ≤ N8 ≤ 1.542; The refractive index of the ninth lens is N9, where 1.588 ≤ N9 ≤ 1.592; The refractive index of the tenth lens is N10, 1.758≤N10≤1.762; The refractive index of the eleventh lens is N11, 1.538≤N11≤1.542; The refractive index of the twelfth lens is N12, where 1.538 ≤ N12 ≤ 1.
542.
10. A surveillance camera, characterized in that, Includes a zoom lens as described in any one of claims 1 to 9.