What Does The ISO Setting Mean?

Improving Your Photography With The ISO Setting

What is the ISO setting on your camera and how can it improve your photography?

This is a question I am often asked by hobby photographers who want to move out of the auto function on their camera. Learning how to use the settings on your camera will greatly improve your photography.

There is a principle called the ‘magic triangle’. It helps you correctly expose an image using a combination of shutter speed, aperture and ISO settings.

Learning these three settings will help you create better photographs and give you much more enjoyment from your camera.

The Exposure Triangle using ISO settings

How to expose your photographs correctly using the Exposure Triangle with ISO, Shutter Speed and Aperture settings.

What is the ISO setting?

Well, it refers to the sensitivity of your camera to light.

There you go, that’s it.


Is it time for a coffee yet!

So how do you use it? Well, if you remember this simple statement “the higher the ISO number the more light your camera will capture” then it’s a good place to start.

Imagine you are in a dimly lit situation. Changing this setting will allow more light onto your sensor allowing you to capture more detail. Whereas if you were in the auto function of your camera, the image would probably be underexposed.

What To Look Out For With High ISO Settings

Now, as always, there is a downside.

In this case it’s the fact that the higher the ISO number the noisier your image will be.

Whilst this isn’t always a bad thing, it can be a great look, especially if you are going for a grainy black and white portrait image. Back in the days of film – I know, living in the past, as I’m always told – an ISO of 1600 was very grainy. But this is becoming much better managed as technology improves and doesn’t always appear in images until the number goes really high.

One thing to look out for with a high ISO is the quality of the image.

Sometimes the colour gradients aren’t as smooth and can look quite messy especially when you blow up your photo.

blown up print to show ISO details

At 1600 ISO the edges are reasonably sharp and defined.

ISO details of grainy image

But, at 3200 ISO the edges of the statue become slightly grainier and less sharp.


Whilst it’s great to capture more light, you have to think about how you are going to use the final image. If you want it printed to a high quality the grain may put you off and make your images look messy and unprofessional.

As always, it’s best to think about your final image before you press that shutter button.

There you go, that’s what ISO means and how it can improve your photography. I hope I’ve simplified it enough to help you with using your camera. Now it’s time for you to get out there and get clicking – have fun.