Design Nomenclature / Light & Optics
Lens flare
Also called flare, ghosting, ghosts
Artifacts from light reflecting between the elements of a lens instead of passing through — ghosts of the aperture marching across the frame opposite a bright source, plus streaks thrown by the iris blades and any anamorphic geometry. Coatings suppress it; a strong enough source overwhelms them.
In practice
Its position is not free. Ghosts fall on the line running from the source through the frame's centre; flare pasted anywhere else reads as a sticker.
Not to be confused with
- BloomA post-process that bleeds luminance outward from the brightest parts of an image, standing in for scattering in the lens, the sensor's cover glass, or the eye's own media. It is applied to the finished image rather than simulated in the light transport itself.
- Veiling glareStray light scattered inside a lens or an eye that lands more or less uniformly across the image, adding a luminance floor everywhere. It does not blur the picture; it lifts the blacks, which crushes shadow contrast while leaving the highlights essentially untouched.
- GlareVisual impairment or discomfort caused by a luminance in the field of view far above what the eye is adapted to. Disability glare measurably reduces what can be resolved; discomfort glare merely hurts. Both depend on the ratio to the adaptation level, not on absolute brightness.