How does ISO work?
by SX10 IS - 10/14/09 4:51 PM
After reading the title, you may be thinking, "Ooh boy, we got ourselves a newbie here!" Don't worry, it's not that bad.
I know what it does. I know what it stands for ("International Standards Organization"). I know that ISO is a measurement of light sensitivity. I know that upping the ISO setting is very useful in low-light situations (to create "light", or where the subject is moving very quickly (to reduce blur). I know that various other factors affect the effectiveness. I know, also, that factors such as light-gathering ability (e.g., bigger pixels/photodiodes) affects the degradation that results from too high an ISO setting. I know that ISO is a give-and-take, where the higher the setting, the more "noise" is introduced into the image.
WONDERFUL!!! But how does it all work? Why does a higher ISO result in more noise? How does a higher light sensitivity reduce blur? etc., etc.