What does an AF illuminator do?

[chips]

What does an AF illuminator do? When i take a picture my subject is lit up in a red light which is very annoying because its quite bright! I've turned it off via my cameras menus but was wondering if its actually important for anything or does it just show u wot your focusing on?

sorry bit of a basic question but my cameras manual isnt very informative :roll:

 

[voodoocat]

It's for autofocusing when there isn't enough light.

 

[chips]

ok thank you!