Taking good photos underwater requires a good white light source such as a flash or spotlight. But some wavelengths of light penetrate water more easily than others, and the result is a heavy blue cast. The tint gets progressively deeper as subjects get further from the camera, meaning that corrective filters only work for a narrow range of distances from the lens. A new patent application suggests the solution is to use a camera with a battery of different flashes. Each produces a different wavelength of light, which penetrates water to different extents. A sensor records that effect, making it possible to work out the distance to a subject in the image.

Original post by scubadooby and software by Elliott Back