Could someone please give me a runthrough on the different times to use different iso's. I'm trying to create a little cheat sheet so I can use till I get a handle on everything. I understand that the iso is used to determine how how reactive the film (or the digital) is to light. And I know how the higher the iso, the grainier and more posibility for noise there is. I also know that you are supposed to adjust to adapt to shutter and aperture, but I'd like to know the area. I'd just like to know when to use 100 or when to work up to like 800. Like low light, shining light, nighttime, sunset, dark, lights at night. THanks in advance.