In Digital Photography ISO measures the affectability of the picture sensor.

Similar standards apply as in film photography – the lower the number the less touchy your camera is to light and the better the grain.

Higher numbers mean your sensor turns out to be more delicate to light which enables you to utilize your professional camera in darker circumstances. The cost of doing as such is more grain (in spite of the fact that cameras are enhancing constantly and today numerous can utilize high ISO settings and still get exceptionally useable pictures).

A case of a circumstance you should need to pick a higher ISO would photo an indoor donning occasion where the light is low and your subject is moving quickly. By picking a higher ISO you can utilize a speedier screen speed to solidify the development.

In customary (film) photography ISO (or ASA) was the sign of how touchy a film was to light. It was estimated in numbers (you've likely observed them on films – 100, 200, 400, 800 and so forth). The lower the number the lower the affectability of the film and the better the grain in the shots you're taking.