I can't be sure what ISO stands for anymore without googling it, (been using the abbreviation too many years) but basically it would refer to the sensitivity of film (or in this case digital sensor) and the amount of grain (or noise as it's called in digital).

Here's a quick breakdown; Low ISO numbers mean less grain (noise), but low sensitivity to light. Higher ISO numbers mean more grain (noise), but high sensitivity to light.

Quick examples: (all hand holding, no tripod)

Bright sunlight, moving subject - ISO 50-100

Cloudy day, moving subject - ISO 100-200

Setting sun, moving subject - ISO 400-800

Indoors, moving subject - ISO 400-1600

If you have a tripod and a NON moving subject you can usually get away with lower ISO numbers just use a longer shutter speed.


This may sound a bit weird but I've had many people do this before and they've said it was helpful.... Post a couple pix you took that you think turned out bad, I should be able to kinda give you a rough idea what caused the problems, or what you can do in the future to prevent them if possible. If you have any details about the lighting, or settings (you can find those under properties or info when you right click your pictures usually), those might help narrow it down a bit more. I have a couple friends I help out by email and that's the only way I've figured out to do it since I'm not there when they take the pix. Up to you if you want to or not.