What is ISO and how to use it? With both analog and digital cameras, ISO refers to the same thing: The light sensitivity of either the film or imaging sensor. When you change the ISO on a digital camera, you’re rendering the sensor more or less sensitive to light. One of the greatest features of digital cameras — one that is often taken for granted — is their ability to change ISO on the fly. In the days of film, you were essentially stuck with whatever film speed you loaded into your camera, at least until you finished that particular roll.
We’ll also explore Manual and Bulb mode and finish with the very worthwhile practical session.