Taking Great Photos Part 6 – ISO

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ISO? Holy Hannah, Teachinfourth...what the heck is THAT? You give a few lessons in photography and then you throw out something that sounds like a disease?

I’m so glad you asked me to clarify....

You see, ISO is an abbreviation that stands for International Organization for Standardization—which is something you probably don’t even care about and—more importantly—will probably never use the name of ever again in your lifetime, but it does sound impressive when you can rattle that off at a party to a group of people who don’t know you; it makes you sound all intelligent and brainy.

For the layman’s definition though, ISO is just a fancy way of referring to how sensitive you’re allowing your camera to be to light.

Say what?

Break it down a bit more? You got it…

Tell you what, let’s jump into our time-traveling DeLorean and program the time circuits back to the days before digital cameras hit the market for the majority of the general populace—yeah, sometime around 1999—Prince’s planned year of partying—and we’ll let the flux capacitor and plutonium chamber do the rest.

Now, you remember those little cylindrical canisters your parents—and possibly you—used to buy that allowed you to take 24 pictures, right? Well, ISO is pretty much the same thing as the speed of film you used to buy, but all without the film. Usually when you went to the store, you probably bought 100 or 200 speed film—unless you were planning on taking photos at sporting events, or in low-light situations, in which case you probably forked out a few extra bucks and purchased the 400 speed. Anything higher than that and you had to head to the local business that specialized in film processing and photo supplies to get it.

So, with this in mind, just know that when you pick a higher ISO setting on your digital camera you are telling it—in essence—that you want to take photos at a fast shutter speed in low-light.

Sounds simple enough, doesn’t it?

However, there is always a trade-off when it comes to something like this. I mean, you can’t just magically switch a setting and instantly get better photos without sacrificing something, right? After all, this isn’t Hogwarts...I mean if this was all there was to it, then why not always crank up the ISO to the highest possible number and fire away?

Such a good question.

Well, the reason for this is all because you’ve got to give a little to get a little…and here’s what it is that you have to give up: the higher your ISO setting, the greater ‘noise,’ or grain, you’ll see in your photos.

Wait just a minute, Teachinfourth…why in the world would I want to shoot at a high ISO if I’m only going to get a grainy photo as the result? I mean, what is the point of that?

That is such a good question, I’m glad to see that you’re paying attention.

Well, let’s say that it’s Twilight (no, not that movie about hormonally-ridden teenage girls, overaged pedofile vampires, and shirtless, hunky werewolves) and let’s say that you’re trying to take a photo of a group of friends—without a flash—but all the shots you take come out either really dark OR blurry beyond belief.

Yeah, this has happened to you before, hasn’t it?

Well, if you step up your ISO just a bit, you’re telling your camera to be more sensitive to the existing light. Your camera responds immediately and does just this, giving you a more decently-exposed photo but it also—unfortunately—allows a grainy appearance the higher you go; however, isn’t it much better to have a grainy shot of all your friends than an image that looks like it was shot in Batman’s secret lair?Or one that looks like it was taken while running through the forest from an axe murderer because of that fantastic blurring action you’ve got going on?

Sometimes grain is highly preferable to the alternative…

Yeah, much better.

Here is an example of a photo that I took of my friend’s son where I wanted to freeze the action of him swinging in the late evening-ish light. I wanted to take the photo without a flash because I wanted nothing but natural light, but the sun was just about set and the swings were under heavily-leafed tree branches making quite a bit of shade. In order to stop the action AND get a photo that was properly exposed, I decided to take the shot at 1/500th of a second to ensure that I had no blurring whatsover. I also kicked the ISO up to 1600 because of the low lighting. If you click on the image to bring up a larger version, you’ll see that there is a definite graininess to it.

Now, compare that shot with the one I took below. This one was taken on a shoot several hours earlier in the day where there were much brighter conditions; in addition to this, my subject was not moving so I didn’t need as fast of a shutter speed. I took this shot at 1/125th of a second with an ISO setting of 100. If you click on this image, you will notice that there is little to no noticeable grain in the shot.

The top image, though grainy, is preferable to the first few shots I was rewarded with which were blurry (because of the slow shutter speed) and dark (because of lack of sufficient light). I jacked up my ISO and was willing to take on more grain to capture a beautiful moment in low light that would have been impossible in any other way without a flash or adding another source of artificial light.

So, just as a reminder, you have three things that work together make up a good photo: ISO (sensitivity to light), shutter speed (how quickly the photo is taken) and aperture (the opening size of the lens letting in light) and they all play an important role in exposing your image correctly. These three things work together like lettuce, peanut butter, and bacon creating the ultimate BLT (without the tomato) in a trio of awesomeness. *(Well, actually white balance does play an important role as well, but I don’t want your brain to explode out the backside of your head).

Take one of these three items out, and a good photo is simply not possible.

Have I lost you?

To make this a bit easier, follow these simple tips if your photo is a bit too dark and you can’t do anything about the light source (just remember though, if you’re in full automatic mode, your camera probably won’t allow you to do any of these things...you need to be in just about any of the other modes):

1. Bump up your ISO a bit (but remember, each time you do, you add just a little bit of grain to your image).
2. Open your aperture a little bit more (but remember, this will diminish your ‘in focus’ area).
3. Decrease your shutter speed (but remember, decreasing your shutter speed gives you a greater chance of a blurry photo).

Changing any of these will help you take a well-exposed photo in low light conditions; however, you need to decide which trade-off you are willing to make, and which one will do the best job for you.

Okay, it’s about time to return to the present day and the age of digital, but as a final note, would you like to know my general personal rule when it comes to ISO? Yeah, I knew you would. Here it is: I always shoot at the lowest ISO possible because I want to avoid unnecessary film grain if I can, but I’m willing to take grain if the alternative is no photo at all.

Here’s a good starting place: if you’re outside on a sunny day, start off at 100 and go up from there if you need to. If it’s cloudy out, consider starting off at 200 and then traveling up or down as needed considering how dark it is. If I’m going to be indoors and shooting without a flash (which is my preference), my personal rule of thumb is to shoot images at an ISO set to 1600 just to be safe. If I see that my images are exposed well enough, I take my ISO down as much as I can, but 1600 is usually my starting point.

Wow, we’ve covered a lot today in a short amount of time, so I think it’s about time for you to go out to recess.

Oh, on one final note: remember that when you’re done playing around, put your camera’s settings back to the way they were. I can’t tell you just how many times I’ve accidentally left the ISO far too high or the aperture too wide, literally destroying the depth of field and ruining my next few shots when I’m in a rush, grab my camera, don’t check the settings, and start clicking away.

Now, take your camera, go practice, have fun, and fill a normally TV-ridden evening with a mock photo session with your kids, pets, or the objects around your house. Just like with riding a bike, you’re never going to get any better if you don’t get off the couch, jump on that sucker, and hit the pavement.

Expect some crashes. Don’t be surprised to get some brilliantly awful images that you’ll immediately delete and never admit to the world that you took. But as you get more comfortable with your camera and the way it works, you’ll get better. Also, don’t forget that your camera came with a manual…use it. Look up little hints in the index from time to time and figure out how to access some of its cool features. You just might surprise yourself with some of the things its capable of.

Until next time; shoot ‘til you get it.



Part 1: Introduction
Part 2: About Your Camera
Part 3: Aperture
Part 4: Shutter Speed
Part 5: White Balance
Part 6: ISO
Part 7: The Breath
Part 8: The Rule of Thirds


P.S. If you liked this post, and know of someone who could use the information in it, would you pass it along? I knew you would...after all, you're awesome like that...

Oh, and just for fun: