A lens flare happens when light is scattered, or flared, in a lens system, often in response to a bright light, producing a sometimes undesirable artifact in the image. This happens through light scattered by the … See more

Filter flare
The use of photographic filters can cause flare, particularly ghosts of bright lights (under See more

• Anti-reflective coating, used to reduce lens flare and produces the red and green colors common in lens flare.
• Bokeh, a source of circles around out-of-focus bright points, also due in part to the internals of the lens. See more

A lens flare is often deliberately used to invoke a sense of drama. A lens flare is also useful when added to an artificial or modified image composition because it adds a sense of realism, implying that the image is an un-edited original photograph of a "real life" scene. See more