The focal point is the specific point along the optical axis of a lens where all rays of light from a given subject converge to produce a sharply focused image. It is the position at which the subject appears in clear detail on the film or digital sensor.
Understanding the focal point is essential for achieving precise focus in photography, whether working with manual or autofocus lenses. Properly identifying and controlling the focal point allows photographers to highlight the main subject, create depth of field effects, and ensure that images are crisp and accurately rendered.