A PTZ camera is a motorised camera that can pan (rotate horizontally), tilt (rotate vertically), and zoom under remote or automatic control. Instead of a fixed field of view, an operator can drive it to follow an event, jump to saved "presets", run scheduled patrol "tours", or let it auto-track a moving object. Optical zoom on surveillance PTZs commonly ranges from about 20x to 40x, letting one camera read a face or plate far down a car park.
In standards terms, PTZ control is part of ONVIF Profile S (and Profile T): the profile lets a conformant VMS move a conformant camera without a vendor-specific protocol, though advanced behaviours (precise preset handling, auto-tracking tuning) often still need the camera maker's SDK. The VMS sends movement commands up the same network link that carries the video.
The defining pitfall is that a PTZ only sees where it is pointed. A single PTZ "covering" an area is a coverage illusion: while it is zoomed in on one corner or running a tour, everything else is unrecorded. Good designs pair fixed cameras (continuous wide coverage) with a PTZ (on-demand detail), rather than relying on the PTZ alone. Auto-tracking helps but its reliability varies with scene clutter and lighting.
