Different applications are often best served by selecting a particular type of lens, i.e., a fixed focus lens, or a zoom lens that offers multiple fields of view without the need to refocus.
An iris can be fixed or adjustable, and in the latter case, the control can be manual or automatic.
Automatic iris control (DC-iris or video iris) is achieved by using the light level to send a signal to the motor controlling the iris. A P-iris uses the same principal, but also involves special software for very precise control, as well as preventing the iris from closing too far.
The C-mount and the CS-mount are the most common standards today in network cameras.
The i-CS lens contains information about its own properties, which is read and used by the camera to optimize image quality and to offset barrel distortion and unstable video.
The i-CS lens is a major step forward in lens technology, providing methods for automatic control of focusing and iris opening. The communication between lens and camera uses a freely available protocol, allowing other manufacturers to develop other compatible lenses and cameras.