Refraction is the bending or change in direction of light rays as they pass from one transparent medium to another, such as through a lens element in a camera. This optical phenomenon is fundamental to how lenses focus light and form clear images on film or digital sensors.
Understanding refraction is essential for photographers and lens designers, as it affects image sharpness, magnification, and optical corrections. It is also a key principle behind optical effects such as magnifying lenses, prisms, and special creative techniques in photography.