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  • HD monitor the lens easily overlooked problem

        Lens with ED lens is the key
        In recent years, the concept of high-definition monitors lot of heated discussions. In addition to that we often see the field of urban surveillance, intelligent building, bank surveillance, maritime surveillance, forest fire monitoring are concerned about high-definition monitor system. Seems to mention monitoring system, people immediately think of is HD. HD monitor can really bring us high-definition experience it? Lens play a key role in the imaging process, but also easy to ignore the problem?
        First, A lens with ED lens is the key
        Used surveillance market, we used a fixed focus or manual zoom lens because the monitor closer, generally use the lens focal length in 50mm or less. Anti-dispersion properties of such a scene on the lens is almost no requirements. But once using a motorized zoom lens to the monitoring of the distant target, the dispersion problem prominent (dispersion is visible in the various wavelengths of light through the lens is refracted appears focal shift in the image performance is the object edges blue color or red color bar). Original analog control system, due to the larger pixel size, dispersion is not very prominent, and only in the configuration above 300mm focal length case will show it. Into the HD era, motorized zoom lens in the 120mm focal length segment, has obvious you can see the problem. This material and coating precision lens with higher requirements. Security surveillance camera with the clarity of the lens material is becoming increasingly clear that the impact on the imaging results.
        Second, large-caliber design is the key
        So instead of using ED glass lens will be able to completely solve the problem of remote monitoring? We usually above 720p definition output image to become a high-definition image. According to the free choice of the market, most of them using the 1080p output format. In the field of remote monitoring, the user wishes to HD surveillance system to improve the screen´s pixels, and thus clearer viewing distant targets. HD system based on our practical experience to watch, not only did not make the picture clarity commission, but the screen color reproduction capability, clarity significant attenuation, the clarity of the output image is worse than the D1 quality, even worse than the analog cameras . In the focal length is elongated, the screen becomes black and white screen, the clarity of a serious decline, worse image effect than the same lens with the effect of ultra-low-light cameras. Such a situation is not difficult to understand. We now most of the HD IP camera uses a CMOS chip, illumination performance can only be reached 0.5Lux. Telephoto lens in the process of change in the focal length, the luminous flux will change, the longer the focal length, the luminous flux is worse. When the focal length is stretched to the maximum, the luminous flux is reduced to the weakest. Is during the day, but the camera is, the equivalent of front was blocked, leaving only a small hole through the light. In this case, ordinary HD IP camera will decay because the illumination is not enough to show a picture quality. Can solve this problem in two ways:
        1, the use of HD cameras for remote monitoring design, such as HD-SDI camera, this camera in addition to the minimum illumination to do of 0.3Lux the same time, but also added to the field of remote monitoring for color reproduction and low light image enhancement technology. Makes luminous flux drops to get a clear picture.
        2, to improve the luminous flux of the lens focal length elongated. The Lens Once produced, the scope of the luminous flux finalized, can not be changed. Therefore we must pick those long focal length in the choice of lens luminous flux better performance. According to the lens of the optical relationship, F (the inverse of the luminous flux) = f (focal length) / D (in front of the camera effective aperture). F value is inversely proportional to the luminous flux, the smaller the value, the better the flux performance. Then in the case of f are the same, select the greater the effective aperture of the lens the better the screen effect obtained.
        The IR function easily be overlooked
        Third, IR function easily be overlooked
        Attention to high-definition systems during the day, is not just concerned about whether to get a clear picture of the main points of the night monitoring performance is concerned. Inside the high-definition systems, IR function is generally forgotten. But with the improvement of the photographic properties of the high-definition system, weather monitoring system, IR function gradually recognized by the users. Power zoom system, IR function is essential. For the system with the the laser illuminator auxiliary light source, IR function is available, will directly affect the ease of use and availability of the system.
        Fourth, Large target surface design adapt to a high degree of IP camera
        HD products in order to improve screen performance, often using photosensitive chip of the target surface. Often these cameras in the configuration of the lens, you will encounter a lot of confusion. Most lens manufacturers the lens still stick to the past times the size of standard analog, or 1/2 "and 1/3". The specifications of the actual situation of the surveillance camera on the market more than the following two:
        1, the use of more than 1/3 "and less than 1/2", 1/2.5 ", 1/2.7, 1/2.8" camera configuration HD lens, 1/3 "lens will be making the screen vignetting. 1/3 "HD lens especially electric zoom almost become tasteless in this application, users are more than 1/2" products. E.g. the KOWA of 7.5-127mm product.
        2, greater than 1/2 "of the product, for example, 1/1.8", 2/3 ". 1/1.8" light-sensitive chip network camera, 1/2 ", or in the configuration of HD lenses or less Vignetting may occur. customers choose to configure, 1/1.8 "mirror ´head as far as possible. This guarantee will not appear to the case of dark corners. Greater than 1/1.8 "specifications, you should select the 2/3" or 1 "product specifications.
        In short, for the high-definition imaging system, relative to the mature analog surveillance systems, there are a lot of people are not very important technical details. Success depends on details, excellent imaging system will consider more. With the increasing popularity of high-definition systems, high-definition lens choice will be more rational, and at the same time as demand is strong, and will in turn promote the escalating development.

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