CCTV camera resolution is measured in lines – the higher this is, the sharper the image will be.  Image quality is also linked to the size and type of chip the camera uses. Generally speaking, smaller CMOS chips are lower quality than larger CCD ones, such as 1/4″ and 1/3″.  Cameras with tiny chips also tend to be able to pick up less light, and therefore produce lower-quality images in low light. The light sensitively is measured in lux, which can range from 130,000 to 0.001 lux. The lower the lux, the better the camera will be at recording when there isn’t a lot of light. You’ll need high-quality images – sufficiently clear for someone to be identified – if CCTV footage is to be used as evidence in court. However, for the best detail, you need a high resolution – this tends to make the camera more expensive, and can take up a lot of storage space. Also make sure the date and time used to ‘tag’ images are set accurately.