People who love photography generally know quite a bit about cameras, lenses and film. And they therefore know all about lens flare, which they sometimes take care to avoid, and other times use for dramatic effects. However, over the last 50 years, fairly sophisticated cameras (film and digital), not to mention camcorders, etc., have been placed in the hands of folks with the cultural, technical and intellectual background of chimpanzees fresh out of Gombe. And the result is that lens flares have become an iconic exhibit of pseudoscience. Lens flares have been exhibited as flying saucers or UFOs since the late 1940s, but lens flares as ghosts have become equally familiar over the past decade.

Just what is a lens flare, and what are some typical pseudoscience applications? When a bright light shines directly into a camera lens, which can have as many as 15 or 20 seperate lens elements inside it, the light bounces around, refracts, reflects, diffracts, scatters, and as a result hits the film in often surprising places, with often surprising appearances. The most common type of flare is a series of polygons (images of the iris diaphragm aperture at the front of the lens) of various sizes, along a line passing through the light source, often seen if the source is nearly centered in the image area. But equally common is a single circular or nearly circular spot, somewhere in the image area— this occurs when the light source is some distance from the center of the image area. Both cases, and some in between, are shown in the four images above. Internet discussions of lens flare can be found here, here, and here.

Film cameras generally need a lot of aperture, the iris is open quite a bit, and the lens flare discs are fairly large and reveal the distinctive polygonal leaf-shape of the diaphragm. But digital cameras don't need as much light, so the apertures are generally quite small, almost pinholes, so that the lens flare discs are often small, compact, apparently circular disks, overexposed and ghostly blue, or pure white. Sometimes the aperture is so tiny that single-slit diffraction patterns can be seen within the disc.

Another type of flare occurs when the light reflects from the inner edge of the lens housing; this produces one or more circular arcs, sometimes showing rainbow-like colors from lens aberration. Far off-axis lights can produce lovely “caustic” shapes, like two curving cones placed rim-to-rim, as the photo on the left at the bottom of this page illustrates.

The lens flare in the dining room in the left-hand photo above can be posted anywhere on the internet as a photo of a supernatural entity, a “ghost orb.” Lens flares in the sky make good flying saucers or UFOs,  as seen in the left-hand shot below, but on the right you'll find a rare shot of ghost orbs watching a flying saucer! Wow!!! Beat that!!!

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