Video Driven, Auto Iris lenses work in a similar way to DC Driven lenses, however, although they are powered from the camera, the lens determines the correct amount of light that passs through it and adjusts the iris accordingly. In previous years, security cameras relied on the lens to control the amount of light reaching the imaging sensor and required a Video Driven (Lens Controlled Iris) type of lens. Video Driven lenses are generally used in older style cameras that do not support the newer DC Driven lenses.