High definition lenses have become the best allies of the security industry, but it is clear that they must be used under clear parameters of quality, compatibility and support.
As david Wang, project manager of the company Hikvision Digital Technology, recognizes, high definition lenses can be used in any application, and especially in the security industry, however, this type of lens can only offer its maximum performance when used together with a camera of the same specifications, that is, HD.
Our guest recommends using high definition solutions (LENS and HD camera) only where it is really necessary, that is, not in applications that have a wider coverage, but in those that require maximum detail, such as airports, passport controls, casinos and financial institutions, to name just a few examples.
As for the choice of lens, our other guest, Ryuhei Sakamoto, representative of the company Tamron, Inc., explains that there are many factors to consider when selecting a lens, but that the most important thing is that the size of the lens image matches the size of the sensor that the camera uses. The resolution of the same must also match that of the sensor in the camera in order to take full advantage of the capabilities of the latter.
It also emphasizes that the light-gathering power of the lens, or the F-number, must also be compatible with the sensitivity of the camera in order to ensure a visible image. In addition to being a good complement with the camera, the lens should also be to make excellent equipment with the particular security application.
He also told us about applications that require a large field of view, which involves the use of a wide-angle lens, while a telephoto lens is necessary when the lens and photographic subject are far apart from each other. In addition, outdoor applications in which lighting conditions are constantly changing, will require the appliance to have an auto iris function in order to adjust the amount of light passing through the lens. If changes in lighting conditions are extreme and the application requires night vision, in addition to normal imaging, day-night lenses with infrared correction will be required.
David Wang complements the above by highlighting that when you intend to change a lens it is important to keep in mind that the resolution of the same and the size of the image must match the CCD / CMOS of the security cameras, also that the performance of the lens (such as the focal length, the iris, and the ability to avoid distortion, ghost image, etc.) must match the requirements of the projects, just as they deliver ease of installation and tuning.
He explains that "lenses should be used that provide a guarantee of a complete image, that is excellent from the center to the edge, also that allows ease of adjustment in order to obtain the best focus."
On the other hand, Ryuhei Sakamoto points out that "high-definition cameras have a higher number of pixels than SD cameras, resulting in high image resolution. The lens that is used with the high-definition camera, therefore, has to deliver a high image resolution."
In the same vein, he stresses that all the elements and factors that must be considered when choosing a standard lens, in the case of a standard camera, must also be taken into account when selecting a high-definition lens. In this aspect it is important that the image size, resolution, and F- number of the lens must match the camera.
The representative of the company Tamron, Inc. also ponders that "although many of the lenses can be used with a variety of cameras from various manufacturers, the lenses are designed with the specific construction of today's cameras. To be useful, lenses must have the image at size, resolution, and brightness specifications that match these cameras; however, lenses are most often used with a camera to capture light, a lens can also be used to project light rather than pick it up."
On the other hand, our guest of Hikvision Digital Technology clarifies us about the concern that has been expressed by the manufacturers of HD camera towards the lens industry and its reduced offer for this type of cameras.
"This is a temporary phenomenon caused by the speed of incompatible development between camera and lens manufacturers. Recently, more and more lens manufacturers have released high-definition lenses for HD camera users, so they have a variety of options to choose from," he explains.
David Wang also raises two situations for this phenomenon:
1. HD cameras use CCD/CMOS that are only for surveillance applications: Since the sales volume of cameras using the sensors can be predicted, there are more lens manufacturers who are willing to develop these devices to work with the sensors at the same pace. For example, the latest high-definition CMOS developed by Sony or OmniVision already have large lens manufacturers developing products to their specifications.
2. HD cameras use CCD/CMOS that is developed for other markets, such as digital cameras: As the market for camera products are not so clear, lens manufacturers usually wait for the products to reach a certain volume of development to produce compatible lenses. The time difference would usually be a year or more. In this case, it is necessary for these industries to unite in the goal of working on the development of compatible lenses on the market more quickly.
For his part, the representative of Tamron Inc., ensures in this regard that they are working hard to develop an increasingly complete range of HD and mega-pixel lenses with a variety of focal lengths, and are also developing Mega-Pixel Day-Night lenses, lenses that maintain a Mega-Pixel resolution in visible light and in infrared lighting.
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