Image Sensors

Most CCTV cameras are now almost exclusively ‘CCD’ sensor type. CCD stands for Charge-Coupled Devices.
These are light-sensitive chips, the sensitive area being split into a large number of individual pixels. An image from a scene is focused through a lens onto the chip surface and charge is built up in each pixel proportional to the intensity of the light falling on it. Hence an electrical representation of the optical image is formed.

These image sensors come in several sizes, but for CCTV the main ones are:

• 1/2”
• 1/3”
• 1/4”

The most common of the above is the 1/3” CCD, which is suitable for over 90% of CCTV applications. The main point to bare in mind if buying a lens separately from the camera, is to make sure the CCD and lens are compatible.

“To keep things simple, stick to the same size. if 1/3” CCD, then choose a lens with 1/3” image format. Never Use a smaller CCD than the Lens Image format!”

The other image sensor type is “Cmos”, this is rarely used in good quality CCTV cameras, however some IP cameras still use it. Also bare in mind it is widely accepted that SONY produce the best quality CCD image sensors, so we recommend you choose a camera with a SONY chip.