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Lens - A lens is an optical device which bends light, focusing it on onto a image sensor to create a distinct, visible image. All video cameras (and still cameras) need lenses in order to obtain a clear picture. Lenses come in a variety of focal lengths. The focal length of a lens, in combination with the size of the imager, will determine its field of view.

LAN Local Area Network. A group of computers and associated devices that share a common communications line.

LED Light Emitting Diode.

Lens Mount The area where a lens is mounted. There are two types; C- or CS-Mount.

Lens Speed Optical speed, expressed by f-number. Smaller f-number means faster lens.

Lens Selection - Atss offers many lens choices, but they vary by camera. At the bottom of each camera's specifications, its optional lenses are listed. For lens exchangeable cameras, there are a wide variety of lenses to choose from. In order to take the confusion out of selecting a lens, please click here to view a lens chart for 1/3" CCD cameras. So long as the distance and video target area have been determined, this chart makes lens selection a breeze.

Line Amplifier This device takes a weak video signal as its input and outputs a new stronger version of the same signal. These are useful/necessary for transmitting video over very long cable runs. This is sometimes known as a video line corrector.

Line Fed Camera refers to the use of equipment that can provide power to the camera and take the video signal along the same cable. It normally involves placing an "encoder" unit at one end and a "decoder" unit at the other. These units effectively combine and then split the power from the video signal at either end of the cable run.

Looping refers to connecting an additional device in parallel with an existing video cable. For example, when driving a video recorder as well as a monitor from the same video signal, simply by T'ing off the cable.

Line-of-sight (a.k.a. LOS) Range refers to the ideal broadcast range of wireless audio/video link (transmitter and receiver) systems. Line-of-sight means the range when there is a visible pathway between the transmitter antenna and the receiver antenna. As well, the line-of-sight specification indicates performance under absolute best conditions. Please be aware that just like home cordless telephones, TV reception, and cellular phone reception, wireless audio/video equipment can often be less than perfect! All wireless products are subject to limitations and vulnerabilities due to many potential variables.

LL  Line Lock mode LUX Lumens per Square Meter; unit of illumination amount.

Linux is a computer operating system platform upon which the software for many high quality standalone / network DVR video recorders is based. Due to reliability concerns and software glitches associated with Windows® as an operating system platform, using a PC-based video recorder for security or surveillance purposes is never recommended. All DVRs found on Atss feature embedded operating system platforms built on Linux.

Liquid Crystal Display (LCD) This is a technology used for flat screen displays. Aside from being smaller and lighter, it also has the advantage of using less power than traditional cathode ray tube screens.

Low Light (or low lux) Sensitivity refers to a camera's performance under low lighting conditions. Although many camera distributors flash very low light "lux" numbers, these numbers often times have nothing to do with real world performance. Specifications offered by CCD manufacturers list the absolute lowest light level at which some pixels will be altered. However, a human being looking at that recorded video will never be able to distinguish anything under the lowest lighting conditions (near pitch black). Please understand that the latest Sony 1/3 " Ex-View and Super HAD CCD chip sets have the best low light performance of any such other CCTV cameras on the market today.

Lux is a measure of light in terms of candle power (measured in foot candles). Lux is often given as a technical specification for cameras to describe the lowest level of light required for the camera to produce any kind of an image. However, this number lists the absolute lowest level of light needed to move ANY of the image sensor's pixels. Since humans cannot detect this change in the image or let alone make out a distinguishable picture, this manufacturer specification is often exaggerated and misleading. Although generally speaking a lower "lux" rating indicates performance in darker conditions, the number listed cannot give a real determination of real-world performance. Eyespyvideo.com CCD cameras have been selected with the best low light sensitivity available (regardless of what any specs may claim).

This is a measure of the amount of light striking a surface. i.e. the luminus flux density at a surface. One lux is one lumen per square metre. Cameras for use in good lighting conditions, or in daylight would normally be rated at 2 Lux or more. Cameras with a Lux rating of 0.2 Lux or less would be considered low-light cameras. It is not possible to get good colour definition in low light levels, so in general low light cameras are always monochrome. However, day/night cameras use electronics to switch from colour during the daytime, to monochrome during night or low light conditions. Many low light cameras are also infra-red sensitive, so that infra-red illumination can be used. Particularly useful in zero light conditions.

Luminance refers to the part of a video signal that carries the monochrome information. i.e. brightness information.