The ISO doesn't just make an image grainier, it makes the camera more sensitive to light and therefore if you're in really dark conditions, you just make the ISO from 50 to 800+ and the image instantly becomes lighter. It's great for night and indoor stuff.
A side note: Your f-stop needs to be at a lower setting when paired with a higher ISO in low light settings. On cameras that are not that great, though, the higher ISO usually does result in a grainier picture, and the result is you cannot enlarge it like a picture with a lower ISO.
Comments