When you take a flash photograph, the brightness can dazzle people, disrupting the composition of subsequent shots and annoying their subjects.
Today’s invention is therefore a flash gun, equipped with face recognition. This allows it to know where any eyes are located within the image.
Just before the flashgun fires, an LCD mask over the flash window blanks out a patch corresponding to the rays heading to any pairs of eyes in the scene.
Although diffraction around the mask would cause some flash light to enter people’s eyes, the intensity could be arranged to be so low that the flash event itself went largely unnoticed.
The result would be effective illumination, without dazzling anyone, and also enabling largely unobserved photography.