You can make a few simple changes in your DSLR camera’s ISO settings to easily improve your photography. Find out how.
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You Can Change Your Photo’s Brightness with ISO
“What speed film are you shooting?” a classmate in college asked me.
“One hundred,” I answered. “What about you?”
“I still have a roll of 400 in my camera,” he told me, “I have to use it up so I can change back to 100 for our still life assignment.”
“Oh, bummer,” I commiserated. “Do you have a roll of 24 exposures?”
“Thirty-six,” he said with a sigh. “I’m a poor college student. These assignments are killing me.”
“Next week we’re supposed to learn how to roll our own film,” I assured him. “Once we do that you can have as many or as few exposures as you want.”
“What a relief!”
This conversation took place over thirty years ago, and most of what we said seems like a foreign language today. Very few people shoot film nowadays, and most people have only vague memories that film came in different speeds (100, 400, and 800).
And with today’s large capacity SD cards, most photographers don’t have to worry about running out of film in the middle of a photoshoot. But back to the concept of film speed. My ancient Olympus OM-1 had a special dial where I could set the camera’s film speed—I just had to remember to change it along with the new roll of film if I decided to change my film speed.
But What Exactly IS ISO?
ISO stands for International Organization Standardization. Go figure—we call it ISO, but it’s actually IOS. Anyway, a quick look at the ISO website gives the reader the idea that the purpose of the company is to maintain world-wide standards for items. In the case of photography, how digital cameras adjust for brightness in a photo.
Back in the dark ages (ok, when I was in college), the ‘speed’ of the film determined the quality of the photograph. My photography teacher told us ISO 100 film would give us the most color and depth in our photos. But, if we had to take photos of fast-moving objects, film with an ISO of 400 or 800 would produce acceptable photos.
Today, digital camera owners can change the ISO with the flick of a knob. The gold-standard remains at ISO 100, though. My Canon 6D has an ISO range of 100 to 25,600. The lower the ISO speed, the less ‘noise’ your photo will have. Digital noise shows up as a grainy-looking photo as opposed to a tack-sharp photo.
According to Nasim Mansurov, ISO is not part of exposure, but it does control the brightness of your photo. Sound confusing? Each time you increase the ISO you double the brightness of the photo without changing the aperture or shutter speed.
A good rule of thumb you’ll want to follow when you start exploring your camera’s manual settings is to keep your ISO double your camera lens length. For example, if you have a 50mm lens, you’ll want to keep your ISO at 100. But if you have a 400mm lens (a telephoto lens), you can push your ISO to 800 and still get great results. You’ll want to experiment and make changes in your ISO settings for different situations. I usually make the ISO higher when I photograph wildlife and lower when I photograph landscapes or people.
How to Know When to Make Changes in Your ISO Settings
If you use a high ISO setting on your camera, you will end up with digital noise. the lower the ISO, the higher the quality of your photos. Take, for instance, these photos of a Berylline Hummingbird. The sun had not quite risen, so I had a low-light situation. In addition, hummingbirds move their wings at approximately 50 beats per second.
In order to get enough light into the camera to capture the Berylline Hummingbird, I would need a high ISO, a slower shutter speed, and a smaller f-stop (which means a larger aperture). I also had a limited amount of time, because other birders reported the Berylline Hummingbird only came to the feeders for 5-10 minutes—if it came at all.
I managed to get a few good shots of the Berylline Hummingbird despite the challenges. But you’ll notice what happened when I changed the ISO to a higher number. The photo turned out much grainier than the photo of a Broad-billed Hummingbird taken at the same location later in the day.
I had the ISO set at 3200. You’ll notice the ‘noise’ or grainy-looking dots in the photo. This photo was taken later in the day and the ISO was set to 400.
The more expensive the camera, the higher the ISO capabilities. The higher the ISO, the less light you need, but the greater the possibility of having a grainy photo. In other words, just because your camera has an ISO setting for 25,600, doesn’t mean you’d ever have any use for it.
I mess around with ISO settings most often when taking photos of birds. Why? Light conditions change rapidly, depending upon where the target bird has hopped or flown to. Try convincing a Ruby-crowned Kinglet to sit still long enough for you to take his portrait and you’ll know what I mean.
I’ve shot thousands of blurry photos (or shots that started head-on and ended up butt shots) of Ruby-crowned Kinglets. But when I change my ISO to a higher setting, I have a better chance of getting a good photo. When I make one small change (ISO), I get better photos.
Your Assignment for the Day
Find an object and photograph it multiple times, experimenting with your ISO settings. Ideally, do this in a bad light situation.
DSLR:
- Move that mode dial to [Av] or [A].
- Check your camera’s ISO. It should be set on 100 (or whatever your lowest number).
- Set your camera to the smallest f-stop. On my telephoto lens, it’s 5.6.
- Take a photo, and then change the ISO one value (from 100–>125). Leave everything else the same.
- Increase the ISO one value (from 125–>160) and take another photo. Continue all the way through your camera’s highest ISO value.
- Load all the photos on your computer and pay attention to which photos look the best and which ones look the worst.
- You should notice how in low light situations, your photos with the lower ISO might turn out blurry.
- Experiment with using a tripod (or a small beanbag to stabilize your camera)
- Now go through the same experiment with your camera in [Tv] or [S] mode.
Point and Shoot:
You get a mixed bag with point and shoot cameras. My Nikon CoolPix waterproof camera doesn’t have an operator-adjustable ISO. But this Canon PowerShot does.
Nikon has some CoolPix camera options that also have an adjustable ISO.
You’ll need to check your camera controls to see whether or not you can control your ISO. If you can, use the instructions for the DSLR camera to experiment with the ISO on your point and shoot camera.
iPhone:
You can download a free app called Yamera for your iPhone that allows you to control ISO, shutter speed, white balance, and exposure. With a paid subscription, you can do even more.
Come Back Tomorrow
Tomorrow I’ll talk about the importance of sticking around.

My ISO setting is one that I do routinely change, but now I’m wondering if I change it too frequently when it’s not really necessary? I’ll experiment today!
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Let me know what the results were!
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The Berylline is a cute Hummingbird! Great capture! Thanks for the Yamera app suggestion. I downloaded it and tried a couple of shots.
Lisa Blair recently posted…February’s Musings – #Write28days Challenge 2021
He’s adorable, isn’t he?
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