A coupled rangefinder is a camera focusing system that links the rangefinder mechanism directly to the lens. As the photographer adjusts the rangefinder to achieve correct focus, the lens automatically moves to the corresponding focus distance. This system allows for precise, quick, and convenient focusing, particularly in cameras without through-the-lens viewing, such as classic rangefinder cameras. Coupled rangefinders are valued for their accuracy, efficiency, and reliability in both street and portrait photography.