Dec 15 2007
What is Lens Flare
Lens flare is a phenomenon which occurs when light which is not used to produce an image enters the lens and afterwards ending up at the camera¡¦s digital sensor or film. Lens flare frequently comes to light as a characteristic polygonal shape. The sides of the polygonal shape are dependent on lens diaphragm¡¦s shape.
Lens flare is often undesired and can significantly lower the overall contrast of an image or photograph. Despite the undesired properties of lens flare, some types of flares may intensify the artistic value of an image or photo.
Several forms of flare may exist, including one or all the polygonal shapes, veiling flare or bright streaks.
Mechanisms of Lens Flare
A simple lens camera system consists of a number of lens elements. Lens flare is a result of non-imaging light that does not directly refract along its determined path and instead reflects internally back and forth for a number of times on the lens elements before ending up finally at the digital sensor or film.
Even though the main cause of flare is internal reflections, a very intense light source is often needed for lens flare to become important. Light source which causes lens flare includes the sun and artificial lighting. Stray light may also leads to lens flare if it strikes the frontal elements of the camera. Also if ordinary light that is outside the viewing angle reflects and may travel through on an unintended path to the film or sensor.
Source: AZoOptics