Basic flare-like effects, for instance in computer and video games, can be obtained using static or animated starburst, ring, and disc textures that are moved according to the position of the light source. Lens flare was one of the first special effects developed for computer graphics because it can be imitated using relatively simple means.
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.įor both of these reasons (implying realism and/or drama) artificial lens flare is a common effect in various graphics editing programs, although its use can be a point of contention among professional graphic designers. Lens flare on Borobudur stairs to enhance the sense of ascendingĪ lens flare is often deliberately used to invoke a sense of drama. This is most commonly seen in car headlights in a dark scene, and may be desired as part of the "film look". When using an anamorphic lens, as is common in analog cinematography, lens flare can manifest itself as horizontal lines. Filters can be attached to the camera lens which will also minimise lens flare, which is especially useful for outdoor photographers. In a studio, a gobo or set of barn doors can be attached to the lighting to keep it from shining on the camera. This can be avoided by shading the lens using a lens hood. When a bright light source is shining on the lens but not in its field of view, lens flare appears as a haze that washes out the image and reduces contrast. In some situations, eyelashes can also create flare-like irregularities, although these are technically diffraction artifacts. Such internal scattering is also present in the human eye, and manifests in an unwanted veiling glare most obvious when viewing very bright lights or highly reflective surfaces. For example, if the lens has a 6-bladed aperture, the flare may have a hexagonal pattern. The specific spatial distribution of the flare depends on the shape of the aperture of the image formation elements. Lens flare patterns typically spread widely across the scene and change location with the camera's movement relative to light sources, tracking with the light position and fading as the camera points away from the bright light until it causes no flare at all. The spatial distribution of the lens flare typically manifests as several starbursts, rings, or circles in a row across the image or view. For good-quality optical systems, and for most images (which do not have a bright light shining into the lens), flare is a secondary effect that is widely distributed across the image and thus not visible, although it does reduce contrast. Most commonly, this occurs when aiming toward the Sun (when the Sun is in frame or the lens is pointed sunward), and is reduced by using a lens hood or other shade.
Visible artifacts, usually in the shape of the aperture made by the iris diaphragm, are formed when light follows a pathway through the lens that contains one or more reflections from the lens surfaces.įlare is particularly caused by very bright light sources. The glare makes the image look "washed out" by reducing contrast and color saturation (adding light to dark image regions, and adding white to saturated regions, reducing their saturation). There are two types of flare: visible artifacts and glare across the image. These mechanisms differ from the focused image generation mechanism, which depends on rays from the refraction of light from the subject itself. Lenses with large numbers of elements such as zooms tend to have more lens flare, as they contain a relatively large number of interfaces at which internal scattering may occur. This happens through light scattered by the imaging mechanism itself, for example through internal reflection and forward scatter from material imperfections in the lens. 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.