Back to basics: Artificial light

Peter Rowlands · Issue 17, Feb/Mar 2004 · pp. 54–61

54 Back to basics Artificial light by Peter Rowlands Water acts as a strong filter which mutes and alters the natural colours of underwater subjects. Artificial light, in the form of electronic flash or strobe, is added to counteract this and restore the colour and detail. Artificial light sources Electronic flash/strobe is the most widely used artificial light source in still photography. These devices give a bright pulse of light which, when timed to coincide with the shutter being open, gives the impression of the photograph being taken by daylight. The typical duration of the flash is around 1/1000th of a second and will be even faster with TTL systems used at wide apertures. This bright pulse of light must be taken into account when calculating the correct exposure and the aperture you choose will depend on: A.The power of the flash B.The flash to subject distance. The power of a fl…