Once again these systems are available to all budget ranges. They go from simple observation systems to those that record. Recording can be done by a special DVR or NVR, digitally which has huge advantages such as multi-camera recording and remote viewing even from another country. Storage of the information offsite is also possible.
The other factor is the cameras which can go from the traditional camera to dome cameras. Those made especially for outdoor use, there are even some for underwater and high-heat use.
The PTZ camera (pan, tilt, zoom) can be moved in any direction and even zoom in on objects, these range from x10 optical zoom and upwards
Another side to cameras is the covert or (hidden) side. They come as clocks, exit signs, motion sensors, smoke detectors, buttons and pinhole cameras which can be disguised as pretty much anything the client can imagine.
For the truly specialized end fibre optic cameras or wireless cameras on mobile devices can be used in high-risk areas.