The Sony A-mount is a lens mount system developed by Sony for its digital single-lens reflex (DSLR) cameras. Introduced in 2006, it allows users to attach a variety of lenses, including those from the earlier Minolta A-mount system, providing flexibility and compatibility for photographers. A-mount cameras feature a mirror mechanism, which enables an optical viewfinder for real-time image composition. This system supports both full-frame and APS-C sensor formats, catering to different photography needs. The A-mount has been largely succeeded by the E-mount system, which is used in Sony's mirrorless camera lineup.