Thursday, February 26, 2009

{ Camera Fun - ISO what the heck is it? }


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.
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.
Here's some more examples:

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.


  1. Yikes! I'll have to go back and re-read much info and I'll have to have my brain in gear...not after a day of teaching 12 year olds! I'm very interested in trying to understand this...but not tonight. I'll get back to it later, but thanks for taking the time to explore all this.

  2. Wow, that's really cool - will definitely have to try that, I get so frustrated with the "no-flash" situation with my camera... I took a bunch of pics of the kids in a school play week before last and they didn't turn out very well so next time I will know better what to do! Thanks!

    Just wanted to stop by quick to let you know I will pray for your DH's exam to go well tomorrow. I figure if I pray here and there all day it will account for the time zone difference LOL

    Have a great day -


  3. Makes my head spin but I think I got it... Thanks

  4. Thanks for explaining.. I've just been using auto but now I'm going to start playing with my camera.

  5. I never understood ISO. Thanks for explaining and showing the pictures.

  6. Thank you for explaining that! I've never understood what the ISO meant. I have extreme trouble taking pictures in the gym (where all of the kids performances seem to be). Will the ISO help on that? The pictures always turn out dark. I have a Cannon Power Shot A570 IS

    Thanks again!
    God bless,

  7. These camera posts are super helpful! It's hard to find someone to explain things to you in every day terms since it's mostly experts doing the explaining. Thanks a lot!

  8. You don't even KNOW how helpful this was! I got a new camera for Christmas and just the other day, after many frustrating photos, finally got the book out. It was not were. Thanks:)

  9. Take it from a girl who keeps her camera on auto, I am so glad you published this post. I always have problems with indoor events and lighting. Also sports where there is a lot of movement. I am going to practice a little with the ISO. The way you put it is a lot easier to understand then my booklet which doesn't give examples like candles on a cake at a birthday party. It's also great that you gave examples with photographs. Keep posting so I can actually learn how to use my camera.

  10. This has been fun. I decided to join you each week and talk about the features on my camera.

  11. Hey,

    Were you on Troyers Loving Life blog today? I tried the link but it didn't come up. I am trying to talk Kristin into a zip line. Maybe we could all go together :) I told her to come on down here and visit.
    Loved your pics. I would love to do more but I get overwhelmed with it all. I have just a point and shoot.
    We just must have passed by you when we went to the Wildlife World Zoo. Wow the prices are high even with a coupon! Anywho, it was fun for the boys to see the planes go over. There were lots of panes that day.


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