What is a Auto Iris?
Source: LS VISION
A camera iris is the part of the camera that controls how much light comes through the lens. If the iris creates a larger opening, more light can get through; a smaller opening allows less light through. The light that the iris allows through hits the?image sensor?and that light gets recorded as electrical impulses that create the video.
A lens with Auto-Iris Control has a motorized iris that adjusts automatically to only allow a specific amount of light to pass to the imaging sensor / CCD sensor. If the lighting conditions are very bright the lens will close the iris to reduce the amount of light that is passing to the imaging sensor. Same is true if there is very low light, the lens will open to allow more light to pass to the imaging senor making the image appear brighter. The major benefit to the Auto-Iris lens is that they will adjust to any lighting conditions. This can be?very useful in a situation where a camera is installed outside of a building, the camera as the light changes during the day will change the iris to help maintain the picture quality.
Auto iris lens are options on most cameras. Most box / long body style cameras accept either Manual or Auto-Iris style lens. The lens does require power so make sure the the camera that you are selecting has the option for an Auto-Iris lens.