I'm sure you've heard people talking about ISO and photography and I'm sure just like me, you are probably confused wondering what it means and how it affects your photos.
In Digital Photography ISO measures the sensitivity of the image sensor. The same principles apply as in film photography - the lower the number the less sensitive your camera is to light and the finer the grain. Higher ISO settings are generally used in darker situations to get faster shutter speeds (for example an indoor sports event when you want to freeze the action in lower light) - however the cost is noisier shots.That's great, but I still wanted to know how this affects me and if I really need to worry about it when taking photos around the house. The answer is, no, not really, I mean it depends on what exactly I'm planning to photograph. But I tell you, understanding what it is and what it does opened up a whole new world for me....suddenly a lot of my photographs make sense....who hasn't taken a shot only to discover it's grainy?
For example, I took a series of shots and I changed the ISO in each....just to show you and then I'll explain how I did it.
ISO 3200 - look how grainy it looks, you see it better on the blue of the feeder
ISO 800 - Still grainy but not as bad
ISO 100 - perfectly crisp shot, little noise or grain
I used to take all my photos in AUTO mode, which means the camera picked the best setting for whatever it thought was the best mode for what I was photographing. It generally tries to keep the ISO at it's lowest but not all the time, because I found that I was getting grainy shots, and it was frustrating as I had no idea what I was doing wrong.
Your camera should let you change your ISO, mine obviously won't let me do it in Auto mode so I need to switch it to Program Mode.
Changing your ISO also means it affects your shutter speed, the higher the ISO the fastest the shutter speed.
Here's some things to keep in mind when you're taking the shot.
If there is plenty of light and I'm shooting something stationary, like a flower or the sky or a tree or whatever, then I don't want grain, which means, my ISO setting should be pretty low. I use ISO 100 and that's the one that gives me the crisp clear shots.
If it's dark or I'm shooting the kids running around or action pics, then I increase my ISO to about 400 or so, because it gives me a faster shutter speed which means I can get all the movement without it turning into a blur.
Situations where you might need to push ISO to higher settings include:
Indoor Sports Events - where your subject is moving fast yet you may have limited light available.Here's some more examples:
Concerts - also low in light and often ‘no-flash’ zones
Art Galleries, Churches etc- many galleries have rules against using a flash and of course being indoors are not well lit.
Birthday Parties - blowing out the candles in a dark room can give you a nice moody shot which would be ruined by a bright flash. Increasing the ISO can help capture the scene.
ISO 3200 - again you can see the grain and noise
ISO 800 - much better but still not as crisp as I like
ISO 100 - perfect
I hope I was able to explain the ISO setting without making you want to run for the hills or take a tylenol for the headache you got trying to decipher what it all means.
Take a look at the honeysuckle photos beneath, the top one is with an ISO of 100 and the bottom one is with an ISO of 3200. Click on them to enlarge so you can see the difference.
It's pretty easy once you know what it does and how it affects your shots. So go on, go play with your ISO setting....take some shots and then come back and show me. Next time, I'm going to talk all about Shutter Speeds.