Variety and innovation mean installation flexibility when it comes to lenses for closed-circuit television surveillance (CCTV). That’s just what the end-user needs: a camera and lens that can satisfy whatever the surveillance application dictates.
Like cameras with their microprocessor innovation and digital signal processing, lens technology has improved, offering the installing contractor more variables than ever and the ability to custom-tailor the application. For example, lenses can operate in extremely low light levels, or offer super-wide angles to capture a large area clearly.
Heart and soul
Because it has become such a popular market and many tradesmen, integrators, electrical contractors, security technicians and end-users are installing cameras, manufacturers have focused their attention on education, providing tools to ensure buyers get the perfect product for the project.
Manufacturers and distributors in the CCTV industry offer a commendable array of support materials to help specify the right lens for the application. For example, online lens calculators allow the installer to plug in parameters and find an appropriate lens.
A lens calculator available from Video Security Specialists Inc., Burbank, Calif., at www.videosecurityspecialists.com is one tool, and another, from Rainbow CCTV, Irvine, Calif., is also ready to use at www.isorainbow.com. In many cases, manufacturers now offer modular cameras that allow the installer or user to select among a variety of compatible lenses—again, it’s about finding the right surveillance solution.
The right stuff
The selection of a lens is critical, because it directly affects the recorded image, with factors such as distance from the scene, focal length, desired field of view, lighting and camera format affecting the clarity of the image. Remember, in security, a clear image is everything, especially when it comes to recording actions for possible use as evidence.
Auto-iris lenses are increasingly popular and easy to use. They are made for outdoors or applications where lighting conditions may vary. An electronic chip compensates for moderate light changes and the lenses come in a variety of focal lengths, as well as C or CS mounts and super-wide angle, telephoto, DC and video types. The DC type is more economical and designed for newer CCD cameras.
There has also been a hotbed of innovation and growing preference for pinhole and macro lenses for effective and discrete undercover surveillance. Lenses and cameras have become so tiny that they can now be incorporated into everything from clocks to the smallest electronics products.
For the electrical contractor, vari-focal lenses provide flexibility in camera applications because they offer a wide range of focal lengths. In essence, it is a low-cost version of a zoom lens. Focal length adjustments can be made at the lens, virtually eliminating the cost and inventory problems associated with improper lens selection.
According to Roberto Testani, CCTV product manager for Silent Witness Enterprises Ltd. in Surrey, B.C, the vari-focal, auto-iris PrimaView allows cameras to see long distances, with sharp imaging from its 5-50mm lens.
“We developed this camera based on customer feedback for a cost-effective solution that offers a longer field of view,” he said. “This product does the job, without customers having to buy a much higher priced pan/tilt/zoom camera.”
Some cameras are capable of retrieving images in the lowest light levels, also known as “lux.” New camera products on the market have super-fast lenses that enable them to capture quality images in dim and low light levels. In addition, fast lenses that previously yielded low-resolution images have stepped up with sharper picture quality and high resolutions, around 470 lines—even in 0 lux.
Everywhere you look, technology is improving to meet customer demand. EC
O’MARA is the president of DLO Communications in Park Ridge, Ill., specializing in low-voltage. She can be reached at 847.384.1916 or firstname.lastname@example.org.