Back Button Focus – What Is It and Why Should I Use It?

Half-press the shutter release to focus, keep it held down, fully depress to take a photo.

This is a routine that is so ingrained into our photographic minds that it’s hard to imagine any other way. But there is, and it’s much, much better.

Digital cameras these days come with dozens of fancy gimmicks, dazzling features, and shiny new settings for you to tinker with, but there’s one often overlooked feature that can genuinely change the way you shoot…

Back Button Focus.

Now, you might have heard the term before, such as in our Photographer’s Glossary here. Or, you might be wondering what the hell I’m talking about and why you should care. The current method is fine, right?

What is Back Button Focus?

Back button focus pretty much does exactly what it says on the tin – It reassigns the button used to autofocus away from the standard half-press of the shutter release and onto a dedicated button on the back of your camera.

Why, you might be wondering, would you actually want to do that? Doesn’t it just complicate matters by introducing another button?

As it turns out – No, it actually provides a host of benefits.

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No More Focusing and Recomposing

No matter what genre of photography you favour, you’ll undoubtedly be familiar with the tedious process of having to refocus every single time you want to shoot another frame.

This is because every time we want to take a photo we have to go through the autofocus function.

This becomes especially tedious if the subject we want to focus on is outside the standard AF points, because we then have to recompose, focus, and recompose again all while keeping the shutter release half-depressed.

You could try and remember to switch your camera to manual focus in these situations, or you could take the convenient route and go for back button focus!

Why does back button focus solve this issue?

Because the shutter release is now used for one thing, and one thing only: Taking a photo.

You can use your dedicated autofocus button to set the focus, and that remains locked until you press it again, completely unaffected by the shutter release button.

You can now fire away to your heart’s content without ever having to refocus and recompose!

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Shoot in AF-C / AI Servo All the Time

When using the default setting, switching over to continuous autofocus (AF-C / AI Servo) when your subject starts to move is a habit you must get familiar with.

You need to be able to switch over in an instant, but if you’re using one of the more beginner focused cameras this setting might not be that quick and easy to get too.

However, using back button focus takes away the need to ever switch between these focus modes, because focusing only happens when the button is actually pressed.

What does this mean?

So, say you’re shooting a static subject such as a landscape. You can simply press the focus button once and then leave it well alone until you change composition.

You can do all this in continuous autofocus, so if an unexpected bit of wildlife wanders into view you can grab your camera and be ready to go in continuous autofocus.

No need to change any settings at all!

This is especially useful in genres such as portrait photography and wedding photography, where you can focus and recompose using the back button but then be ready to go with continuous autofocus when your subjects begin to move.

To put it bluntly – Back button focus offers you all the benefits of both focusing modes but with none of the pitfalls of either.

Instant Switchover to Manual Focus

You may remember times when your camera has struggled to lock focus on something. Maybe you were shooting macro, where cameras often struggle to find accurate autofocus, or you might have been shooting through wildlife through some long grasses that you wanted out of focus.

Either way, the solution was always to go into your camera and switch to manual focus.

But once again, Back Button Focus comes to the rescue and saves you both time and effort.

Because the shutter release isn’t attempting to autofocus every time you press it, on many lenses you can switch over the manual focus instantly just by adjusting the focus ring on your lens.

Why is this helpful?

We’ll take the example of macro photography. Macro photography is one of those areas of photography that autofocus struggles with. It’s a well known flaw.

This leads many macro photographers down the path of manually focusing for every shot, but we can speed up the process with Back Button Focusing.

Simply use the back button to try and autofocus. If it hits the spot, great stuff, shoot away! If it doesn’t, just make small tweaks to the focus manually until it’s right.

It might seem like a small thing, but just being able to use autofocus to get in the right ball park before fine tuning your focus manually is a massive time and effort saver in the long run.

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How to Set and Use Back Button Focus

I’m sure you found the reasons above compelling enough for you to give back button focusing a go, right?

The next step is to actually set your camera up for it, but the problem is that all the different camera brands come with different ways of getting this set up.

The best solution?

Check your manual. You’re looking for a way to assign the autofocus function to the AE-L / AF-L, and then to take away that function from the shutter release.

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