lensflare

Lens flare, or lens flare, is a visual artifact that occurs when bright light enters a camera lens and scatters or reflects within the optical system. The result is patterns such as halos, rings, starbursts, or colored blobs that may appear in or near the image frame. Flare is caused by reflections between lens elements, the sensor cover glass, and any filters or coatings in the optical path; stray light and dirt can amplify it.

Common forms include ghost images (secondary reflections of the light source), veiling glare (a hazy wash across the image), halos or rings, and starbursts produced by diffraction at the aperture blades. The exact shape, color, and intensity depend on the lens design, focal length, aperture, coatings, and the light’s angle relative to the frame. Wide-angle and fast lenses often show more flare, though coatings and design aim to suppress it.

In photography and filmmaking, flare is often undesirable because it reduces contrast and can wash out colors. It can, however, be used creatively to convey brightness, scale, or a dreamlike mood; anamorphic lenses, for example, commonly produce horizontal lens flares. Digital post-processing can simulate or remove flare, depending on the goal.

Mitigation techniques include using a lens hood or flagging light sources, adjusting shooting angles, and selecting apertures to avoid extreme diffraction. Be aware that smaller apertures (higher f-numbers) can increase starburst patterns. Keeping lenses clean and using high-quality anti-reflective coatings also helps reduce flare. When flare is undesirable, blocking stray light and choosing lenses designed to minimize reflections are standard practices.