Definitions for "Automatic iris"
A lens that adjusts automatically to allow the right amount of light to fall on the imaging device. There is a tiny motor and amplifier built in which receives a control signal from the camera to maintain a constant one volt peak to peak (1.0 Vp-p) video level.
A lens that automatically adjusts to allow the correct amount of light to fall on the imaging device. There are a tiny motor and amplifier built in which generally receives a control signal from the camera to maintain a constant one volt peak to peak (pp) video level. There are two manual controls on the lens to allow compensation for varying conditions of 'peak' and 'average' light.
An electronic circuit fitted to the iris of a lens to help compensate for large changes in light levels. This type of lens is recommended for use where there are low light or changing light conditions, for example external use. An Auto Iris lens adjusts the aperture automatically dependent on the light level, very much like the human eye.