When people ask me about my camera, the discussion often turns to ISO and what it is. But your real question is, “How can I utilize ISO to take better pictures?”

Here’s how, but first here’s what ISO means. In short it is a number that represents the digital camera sensor’s sensitivity to light. Higher = more sensitivity. Numbers usually range from 100 up to 1600 on most cameras. (Pro cameras like my Canon 5D MkII goes up to ISO 25,600 or higher.)

In AUTOMATIC mode, your camera sets the ISO without your involvement based on the available light of your subject. Your owner’s manual includes instruction on manually setting the ISO, which can be helpful.
For example, if you take a picture in low light and zoom in to review your photo and find tons of tiny red and blue spots, especially in the shadow areas, you are seeing “color noise”. Some cameras are better at “noise reduction” than others. To reduce noise, lower the ISO you are using. It’s that simple. Always, always, always use the lowest possible ISO to keep noise at a minimum!

So when would you need a higher ISO? I’m glad you asked. Let’s say your friends are dancing at a club in low light and your photos of them are blurry (subject blur during the exposure). Set your ISO higher so you can use a faster shutter speed to reduce motion blur. Play with ISO vs. shutter speed to find a happy medium of minimal noise with minimal subject blur.

There’s a compromise setting in there somewhere that will be best for the situation.

After awhile you’ll realize that all of photography is a series of compromises:
Shoot tripod mounted for sharper photos vs. freedom of movement for better angles?
Carry a heavy bag and have everything or travel freely with just one lens?
Master available light photography or set up lights for “perfect lighting”?

So give your ISO setting a whirl. And at the next party, I’ll let you explain it… 😉