ABSTRACT
An advantage of the digital camera’s ISO setting is that it can be altered to suit the photographic circumstances. With film, when the light gets poor you load a faster film (such as 400 or 800 ISO) which is more sensitive to light. With digital all these options are built in to the camera, so if the light gets poor you can always increase the ISO setting. Most digital cameras now have a minimum ISO of 100. This can be a definite advantage when you are diving a wreck in 30 m of water and you lose the sunlight behind clouds. It’s then impossible to light the entire wreck with flash, but the natural light becomes too low for a decent exposure. An option is to open the shutter speed, but the trade-off is sharpness when hand-holding. The downside to setting a higher ISO is that the pictures may suffer from noise. Noise is like the grain you get from high-speed films.
