Lens Flare and The Incredible Physics of Modern Lenses

A bare, uncoated air-to-glass surface sends roughly 4 percent of the light striking it back the way it came, and a current professional 24-70mm f/2.8 zoom stacks about 30 of those surfaces in a row. Uncoated, less than a third of the light entering the front would reach the sensor as part of the image. Most of the rest heads back out the front of the lens, and flare is what happens when the fraction that turns around again lands on your picture. [Read More]