What does autofocus mean?
Autofocus is a noun referring to the automatic focusing mechanism found in cameras and other optical devices — a system that adjusts the lens by itself so that the subject appears sharp, without the photographer turning a focusing ring by hand. The term combines the Greek-derived prefix auto- meaning 'self' or 'automatic' with focus, the Latin word for 'hearth' that optics adopted to describe the point where light rays converge. Since becoming standard in consumer cameras in the late twentieth century, autofocus has transformed photography: continuous, face-tracking, and eye-detection variants now let cameras follow moving subjects with little user input. In everyday speech it appears chiefly in photographic and technical contexts, often shortened to AF in camera manuals and enthusiast discussions. Its natural opposite is manual focus, the deliberate human act of adjusting the lens directly.
nounA device or system in a camera that automatically adjusts the lens to bring the subject into sharp focus. More broadly, an automatic focusing mechanism.
- A mechanism in cameras and other optical instruments that adjusts the lens automatically to produce a sharp image.
"The camera's autofocus locked onto her face instantly, even as she moved through the crowd."
"Modern mirrorless cameras use hybrid autofocus systems combining phase detection with contrast detection."
"She switched from autofocus to manual to get precise control over the depth of field."
The word 'focus' comes from Latin for 'hearth' — the fireplace of a Roman home — before optics borrowed it, and 'autofocus' bolted on Greek autos ('self') to make a camera find its own hearth of clarity.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of autofocus
Autofocus is a twentieth-century compound formed from auto-, the combining form of Greek autos meaning 'self', and focus, borrowed from Latin focus meaning 'hearth' or 'fireplace', which was adopted into optical terminology in the seventeenth century to denote the point where converging light rays meet. The compound arose as camera technology developed automatic focusing mechanisms, becoming widespread with the popularization of autofocus cameras in the 1970s and 1980s. It shares its roots with words such as automatic, autonomy, focal, and focal length.
How autofocus is actually used
Autofocus is used almost exclusively in technical and photographic contexts; it is neutral in register. It is often abbreviated AF in photography literature and camera menus.
Easily confused with autofocus
Focus refers generally to the point of sharpness or concentration, while autofocus specifically denotes the automated mechanism that achieves focus without manual adjustment.