Take Better Pictures – Lesson 3

ISO – Sensitivity

ISO stands for International Standards Organization, but that doesn't really describe anything about it.

ISO is a number value that describes how sensitive your camera sensor is to light.

  • Low ISO means less sensitive
  • High ISO means more sensitive
  • ISO numbers typically range from 100 to 6400 in most newer cameras.
  • A few cameras go down to 80 ISO and some go as high as 25,600 ISO! But I wouldn't recommend using that on a regular basis.

On a bright and sunny day there is a lot of light, so you can use a lower ISO setting. 

On a cloudy day there is less light, so you must increase your ISO.

Indoor photos have even less light and if you don't want to use a flash, you can bump up the ISO to compensate for the low light.

Here are some starting points to use:

  • 100 or 200 ISO for Sunny and Bright
  • 400 ISO for cloudy days or indoors near a window
  • 800 ISO for indoors without a flash
  • 1600+ ISO for really low light situations
Fun fact: When you double your ISO, for example from 100 to 200, you double the sensitivity of the sensor to light.

There is a big trade-off to using higher ISO though, and that is the increase in NOISE.

So which setting should you use?

Use the list above as a starting point. For best results always capture your images using the lowest ISO possible. This will reduce the amount of noise in your photos.

Camera technology has improved greatly over the years, and now cameras with smaller and non full frame sensors, you can get a very high ISO without noticing any noise.

You'll find a few more tips in this video.

Your homework for this lesson

ISO test

I suggest you do a noise tolerance test with your camera. 

  • Put your camera on a tripod and set it on Program Mode. That's P on the dial.
  • Take photos of the same scene using all your ISO settings.
  • When viewing your photos up really close on your computer, at some point, the noise is going to be really noticeable.
  • Noise shows up mostly in the shadows (dark) areas of your photos.
  • That point will vary with each camera model, and your own tolerance to ISO will vary as well.

You need to ask yourself, at what point does the noise really bug you? 

Whatever ISO that is, remember it for future reference, as any photos you take at that setting may not be acceptable quality in your eyes.

Having said that, if your daughter is figure skating in a dimly lit arena and you need to capture the action, you may well have to use 3200+ ISO to get a decent shot. In that case, getting the photo is more important than the noise quality.

When I did this test, I had these results:

  • On my old point & shoot camera the threshold was 400 ISO.
  • On my Lumix G9 camera that I use for client work, it was 3200 ISO.

This is due to a better, and also larger sensor of the newer camera.

Camera technology has improved greatly over the years, and now cameras with smaller and non full-frame sensors, can be set at very high ISO without introducing much noise.

What does digital camera noise look like?

Notice the difference between 80 and 1600 ISO in these photos.

Noise looks a bit like film grain. You start to see the image break down into coloured specs and the photo also starts to lose detail. Above is a comparison between two photos taken with ISO 80 (left) and 1600 (right) with my old Canon G9 compact camera.

You can clearly see that the photo taken with 1600 ISO really breaks apart in the transition area from black to orange. Keep in mind that 1600 ISO will likely look different on your camera. And if your camera is new, then I bet 1600 will be perfectly acceptable.

Noise Reduction

You can reduce some amount of noise in your camera by choosing a noise reduction (NR) setting. You should test it out first to see how the different settings affect your images. Sometimes in-camera noise reduction causes unwanted softness.

Noise shows up mostly in the dark areas of your photos, as you'll see once you do your own tests. You can also reduce noise in post processing using the built in tools in Photoshop, Lightroom, Luminar and most other high-end image editing software.

If you reduce noise in your images too much during post processing, they will get softer looking too. It's always best to try and shoot with as little noise as possible, and that is achieved by using a lower ISO.

Every new generation of cameras and sensors deals with noise better. An old digital camera will probably show more noise at the higher ISOs than one you buy today.

Next Lesson: ISO – White Balance

Have a look when you're ready.