CCTV-Zoom Cameras

Zoom refers to an adjustable field of view. Cameras may have manual zoom with a varifocal lens or remote zoom with a powered zoom lens. Some DVR video recorders also have the ability to change the monitoring field of view and zoom in or out on selected areas of a recorded video image.

What is a varifocal or zoom lens camera?

Fixed lens cameras have a set field of view and cannot be manipulated to produce a wider or narrower angle. These are generally found as 3.6mm, 4.3mm, 8mm, 12mm, etc.. The higher the number of the focal length, the more telephoto the effect. *However- this has nothing to do with the actual size of the lens itself. You can obtain a 3.6mm lens which can range in physical size from 1mm (on a micro pinhole type camera) to the size of a soda can (for much larger security type cameras).

Variable focus (or varifocal) lens cameras allow the user to modify the field of view from its widest/ most panoramic to the narrowest and most telephoto views that it is capable of. Some lenses provide a 4-8mm (widest at 4mm and most telephoto at 8mm)- whereas others may provide 5-50mm for a super zoom in ability.

Many are set up to interface with a variety of optional lenses. However, there are also cameras with built-in lenses that cannot be removed or replaced. The removable type mounts are referred to as "C" or "CS" mount because of the type/ size which is an industry standard. Many lens choices are available and the decision should be based on actual requirements for the application. For instance, if a wide field of view is required, there may be no reason to include a feature which allows a zoom to a tighter shot.