It's crucial, but just what is ISO in photography? Here's what it stands for, what the numbers mean, and when to change them ...

So what is ISO in photography? Well ... a camera sensor's photosites introduces a form of visual distortion called noise.

In analogue photography ISO refers to how sensitive the film in ... At higher ISO settings an image is more likely to be affected by digital noise or grain - this can be used intentionally.

In analogue photography ISO refers to how sensitive the film in ... At higher ISO settings an image is more likely to be affected by digital noise or grain - this can be used intentionally.