What Does Infinity Mean When Talking About Cameras and Lenses?

When talking about photography, and specifically photographic lenses the term ‘infinity'(∞) refers a focus setting where everything beyond the lens’ ‘hyperfocal distance’ will be in focus. Technically speaking, when a lens is set to infinity focus, rays of light reaching the photographic medium do so completely parallel to each other. In reality this is not quite the case due to limitations in optical manufacturing. Focusing to infinity allows a photographer to quickly ensure that an object beyond the hyperfocal distance is in focus without having to physically check focus through the camera’s viewfinder. When set to infinity focus objects beyond the hyperfocal point will remain in focus regardless of aperture setting. The advent of autofocus cameras and lenses has made true infinity focusing a less common feature on modern lenses.