Varifocal & Auto-Iris Functions of CCTV

Terms “varifocal” and “Auto Iris” refer to CCTV Camera lens functions.

A varifocal lens is a camera lens with variable focal length in which focus changes as focal length (and magnification) changes, as compared to parfocal (“true”) zoom lens, which remains in focus as the lens zooms (focal length and magnification change). Many so-called “zoom” lenses, particularly in the case of fixed lens cameras, are actually varifocal lenses.

Auto iris lenses are more versatile than fixed iris and manual iris lenses. This is because the camera controls the iris via a 4 pin connector, this allows the camera to adjust the lens to get the best picture given the lighting conditions. Auto iris lenses would be best lens to use in any application as they are flexible and can adjust to changing light levels. An auto iris lens should always be used for outdoor applications where the light levels vary constantly from day to day.