Noise is a big deal if you're shooting in low light. You generally have to bump the ISO up to compensate for it. In simple terms the ISO is the sensitivity of t

Noise is a big deal if you're shooting in low light. You generally have to bump the ISO up to compensate for it. In simple terms the ISO is the sensitivity of the...err...sensor. Higher sensitivity leads to brighter photos but unfortunately more noise. It's especially obvious in larger prints. The reason you don't notice noise is that most camera work actively avoids the situations that causes it. That's why most shots are well lit or taken in day, high iso is typically grainy, people don't usually have the expensive setup required to avoid bumping the ISO up to an inordinate level. Better noise reduction > higher acceptable iso levels > clearer low light photos. Consumer cameras and entry level DSLRs buckle in low light, better noise reduction will reduce the investment required to avoid that.