Do not confuse the quoted IR range of a camera with its optical range. Widely used in marketing the IR range is a pretty much made up number and is supposed to give an indication of how far from the camera you can detect it's built in IR illumination. There is no relationship whatsoever between the IR "range" and the distance at which detail can be captured, the effective range of the camera. Most supposed "25 - 35 metre" cameras have an effective optical range closer to 5 metres, sometimes not even that.
The distance at which you can identify someone is dictated by which lens is fitted to the camera. We discuss camera lens choice elsewhere on the website. When discussing the effective range of our cameras we refer to the distance at which a person can be identified.
It doesn't help that many people selling CCTV seem to confuse IR range with effective optical range. They give an IR range and then go on to describe how people can be identified at that distance. Don't be fooled, they are wrong. People also think that the longer the IR range the better the camera will perform at night. This isn't entirely true either. The sensitivity of the electronics used will be more influential on how well the camera performs in low light. We look at low light performance elsewhere within this camera buying guide.