Like everything else in life you get many different brands, quality differences and specs on these things. The most expensive is not always the best, but don’t buy the cheapest either. Compare apples with apples.

Start by determining what you require. Do you only want to see movement or do you actually want to see that it is a person wearing a blue cap with a moustache and a mole on his chin at 15 metres from the camera? You have to at least check what the resolution (TV lines) of the cameras are and if you are going to record the cameras, at what resolution the DVR records.

In the past the cheaper DVRs recorded @ CIF which is an effective resolution of 352 x 288 pixels per camera while the preview on the screen was usually much higher (e.g. 2CIF or 4CIF). A lot of people made the mistake by not noticing that the recorded resolution was much lower than the previewed resolution, when they looked at the advertised specs.

In layman’s term that means that when you saw the guy walking past the camera everything looked fine on the monitor, but when you played back the recording you could not determine if it was a dog or a human in the picture.

Usually you would want a recording resolution of at least 4CIF or D1 which is an effective resolution of 704 × 576 pixels. Lately some of the recorders records at HD (1280 x 720) […]

Source mybroadband.co.za