A fixed lens camera has a lens that cannot be adjusted after manufacture, so its angle of view is decided before the camera is installed. It is simpler than a varifocal or PTZ model and holds its setting, which means matching the lens to the distance and width of the scene matters more.
Choosing a fixed lens is choosing the view in advance. On a simple site that is an advantage: fewer settings to drift and fewer parts to move.
Fixed, varifocal and PTZ
A fixed lens is set at the factory, a varifocal lens is adjusted on site and then left alone, and a PTZ moves under control. Each step adds flexibility. For a doorway or a corridor at a known distance, a fixed lens removes a setting that can be got wrong.
Getting the lens right up front
Measure the distance, decide the width to cover, and calculate the focal length before ordering. Check the result on site with a test camera or a temporary mount, because a few degrees of aim can matter more than the specification. Once installed, the view does not change by accident.
Related:Commercial security camera systemsGlossary: PTZ camera systems