Think of it as a volume control - turn it up high and you can take pictures in lower light, but there is more of a tendency to distort (noise on the picture)
Have it low and you get all the sensitivity but only when the light is good.
Exposure is basically just the combination of 3 things :
Shutter speed, aperture size and ISO sensitivity. One of the great things about digital over film is that you have much greater control over ISO, being able to change it on a shot by shot basis, rather than roll by roll.
Double the ISO and you can half the shutter speed for the same exposure, and that kind of thing. Some digital cameras handle the noise better than others however. |
