I just came across an article over at digital Photography School titled How to Choose the Right ISO for your Digital Photography. This is a great question especially for those of us who have no idea what it means. ISO is one of those terms in photogaphy many of us never bother to figure out but which can make a huge difference in your photos.
If you are one of those who wants to get a little bit more out of your camera then this article is for you. Go ahead, take your camera off AUTO and start improving your technique.
What ISO is best for my pictures? - Reader Question
Changing the ISO setting on your camera changes the sensitivity to light of the image sensor inside of it.
The lower number that you select the less sensitive the sensor is to light (and conversely the higher the number the more sensitive it becomes).
This is useful when you’re shooting in different lighting situations - particularly when there’s low light and you might not be able to use a flash (you’d bump up your ISO setting in this case).