Security Cameras Specifications and definitions explained, AGC, TVL, HD, AES

 Security Camera Information

CCTV Security Camera Specifications explained

Welcome to our free Online CCTV Specification and Terminology knowledge base. In order to determine the most suitable CCTV Camera type and model for an application, several key aspects of the environment need to be taken into consideration. For every environmental parameter like the lighting conditions, distances etc. there are corresponding technologies designed to adjust the camera for optimal operation under those conditions. These technologies are usually expressed in abbreviations like AGC, BLC, DSS, TVL etc. Having the technologies behind these abbreviations clearly defined and their function explained, will greatly assist in making the right choice. 


The following list of definitions serves as an initial orientation tool. For more elaborate information please select one of the links within the quick references or have a look at the Security Camera Specification Guide Box to the left for detailed listings.

AES - Autom​atic Electronic Shutter

Electronic technology within the camera - regulates light sensitivity and therefore the brightness of the video signal electronically by increasing or reducing the shutter speed (simplified: faster shutter = more 'snapshots per second' = more detail per second (especially fast moving objects are clearer) = but brightness is reduced. AES is the alternative and incompatible of/with an Auto Iris. An Auto Iris regulates illumination by mechanically increasing or decreasing the iris opening within the camera lens.... more

AGC - Automatic Gain Control

Simplified: This technology functions like an amplifier, boosting the initial image signal coming from the CCD chip. The scene illumination can be improved, but also eventual image noise may be amplified as well... more

ATW Auto Tracing White Balance

An extension, or upgrade to the AWB Auto White Balance function. AWB required  manual user action for colour balancing in changing illumination environments. ATW will seamlessly adjust the colour balance for colour temperatures in frequently changing illumination scenarios (such as a camera moving from indoors to outdoors etc.)

AWB Auto White Balance

A technology in the Security Camera, making adjustments to white and gray-scale parameters in video, based on the colour temperatures of the viewed scene. A camera with ATW would be superior, however AWB may be entirely sufficient for camera positions with rare environmental illumination changes. 

CCD Charge Coupled Device

Charge Coupled Digital Image Device - Chip. The chip is positioned immediately behind the lens and converts the analogue light waves hitting its surface into digital image information. 

DSS - Digital Slow Shuttering

Like AES, but with the sole purpose of decreasing the minimum required scene illumination = enabling a camera to work in a dark environment in which it could not perform at a natural shutter speed rate. Reduced Shutter Speed = increased video brightness = but (!) drastically reduced clarity and detail of moving objects and subjects... more


The number of horizontal lines that a camera is able to generate and transform into a clear video signal. Vertical television lines are irrelevant in CCTV Camera Specifications, as these can be achieved without difficulty... more

HD High Definition

Not to be confused with High Resolution of Analogue Cameras. HD is a far higher resolution, which is generally only possible with HD or Megapixel IP Cameras (exception: HD SDI).


The LUX parameter in a camera data-sheet informs you about the minimum required illumination for generation of usable video. Therefore a camera with a lower LUX value is better (!) than one with a higher value... more


Shutter Speed

Simplified: Imagine a camera taking many still snap-shots per second in order to create an animation. More snap-shots per second would result in a smother and more detailed video. A faster shutter speed means more snap-shots per second and more video detail. Shutter speed and illumination however have a detrimental relationship. Therefore the video brightness can be directly controlled by adjusting the shutter speed. Fast shutter speed = darker, slow shutter speed = brighter.

WDR Wide Dynamic Range

Simplified: This function can apply separate brightness settings for individual areas of the same image. WDR is highly recommended in applications where stark contrast and differences in brightness can be expected within the view of one and the same camera... more