The Historical Revolution and Progress of Camera Auto Focus Systems

The auto-focus system is an important part of modern cameras, not only single lens reflex (SLR) cameras but also mirrorless cameras. The reliability level of an auto-focus system usually determines the availability of a camera in the photography industry. Today the photography industry makes more strict requests for auto-focus ability, which means that the camera can work in more complex and difficult environments, such as the Olympics and ecological photography. The paper reviewing past related research and patents points out basic development rules of auto-focus system and prospect futural trends of it. This research found that the auto-focus technology experiences a process from active focus to passive focus, from contrast focusing to phase focusing and mixing focus, from separated focus module to phase detection auto-focus (PDAF). This research points out that several companies and scientists have had hard effects on it. In the future, auto-focus technology will become more reliable and intelligent with artificial intelligence and eye-control focus.