(AI). An automatic method of varying the size of a lens aperture in response to changes in scene illumination.
Auto Iris Lenses adjust for changing light conditions in a camera view. If the sun shines on a camera with an auto iris lens, the lens will adjust the amount of light so the picture remains clear.
The system and/or ability of cameras to automatically adjust picture exposure
is a diaphragm which is inbuilt in a lens to automatically control the amount of light falling on the chip. The tiny motors in the lens open or close the diaphragm, depending upon the amplitude of the video signal.
Cameras with an Auto Iris feature, have the ability to compensate for large variations in light levels. Particularly useful for cameras that need to compensate for changes from bright sunlight to dark shadows. The auto iris circuitry is normally linked to a motorised iris drive that physically opens and shuts the iris on the lens. Closing a physical iris is a much better way to protect a camera from being damaged by bright sunlight then simply using electronics to reduce the signal strength.
