I can’t remember when I became best friends with back button focus. Like all great things, it’s something that I just started using and never looked back.

What is back button focus?

The clue is in the name. The back button focus button is on the back of your camera close to your right thumb and can be assigned the focusing function instead of the shutter button.

This allows the shutter button to be used just for taking the shot only and cuts out the common problem of refocusing between shots.

Exactly which button and what it’s called varies between camera brands so I’ve listed these further down in the article.

Why you should use back button focus?

It’s really quite logical. If you are already focused when you push the shutter button to take the shot, the camera has less to do in that minuscule split second of time.

Of course, without back button focus, you would have been depressing the shutter button slightly to focus anyway ahead of actually fully depressing and taking the shot.

But what if your subject, or you, moved a bit in that brief interval? Your camera would have to refocus before taking the shot.

The back button is a little focus Scout - always prepared.Click To Tweet

Within 5 minutes of first using back button focusing, without even thinking about it, my thumb has not left the back button. Except for when I put my camera down that is. It just makes sense.

Back button focus for moving subjects

When photographing young children back button focusing is essential – they move so fast! All the time.

Further reading: Freezing motion with a fast shutter speed

What button is used for back button focus?

Different camera brands call the back button focus button different names. Even the button used varies between the camera models in each brand. What they all have in common is that the back button focus button is the most convenient button for your right thumb to reach on the back of the camera.

Here’s a list of the buttons top camera brands assign to back button focus:

  • Nikon – AF-ON  or  AE-L/AF-L
  • Canon – AF-ON  or  AE Lock
  • Sony – AF/MF AEL  or  AF-ON
  • Fuji – AF-L  or  AE-L
  • Olympus – AEL/AFL  or  Fn1

What else is involved with back button focus?

To get the most out of back button focus, your autofocus should be set to continuous servo mode for Nikon or AI Servo for Canon. As the name suggests, your camera will continuously focus all the time you hold the button down.

I even use continuous servo for close-up still life images. The subject might not be moving, but I move fractionally every time I breathe in and out. Also, I don’t have a particularly steady hand, which is really annoying for a photographer.

What about autofocus area?

Don’t use auto area autofocus

There is no point being in auto area autofocus, AF-A for Nikon or AI Focus AF for Canon, if you’re using back button focus. It’s far too general and the camera won’t know what you want to focus on.

That’s why if you use this autofocus area you’ll find every now and then that your subject is completely out of focus and some random object in your image is beautifully in focus. I’d go so far as to say, don’t even bother with auto area autofocus.

How to use back button focus

I used single point autofocus in continuous servo with back button focussing and a high shutter speed to ensure a sharp photo of this very fast moving and delightfully goofy dog barrelling down the hill to his owner when called.

Use single point autofocus

Take control of the situation and choose single point autofocus (same terminology for both Nikon and Canon).

Position the focus point on your subject. If you’re photographing a person, and they’re close enough, position the focus point on their eye – the one nearest to you. Do this and your camera will be ready to take a perfectly focused image when the moment arrives.

Here’s a handy cheat sheet for Nikon and Canon autofocus area modes. Pop up your details and we’ll email it to you. As a bonus you’ll also receive our photography tips every Monday. You can unsubscribe at any time, no hard feelings.

Move the focus point

Also, get really, really good at changing your focus point really, really fast to keep up with your subject when using single point autofocus.

I don’t see how you would get a well focused image of a moving subject if you’re not using back button focus, along with continuous autofocus and, either single point autofocus, 9 point dynamic area autofocus or 21 point dynamic area autofocus.

Dynamic area is a Nikon term. Canon’s equivalent terminology is AF point expansion.

Further reading on how to get the most out of your autofocus:

Nail your autofocus, get the shot

How to focus on fast moving subjects

To be a good photographer you need to develop your inner control freak.Click To Tweet

Have you used back button focus?

Have you made the switch to back button focus yet? If so, let us know in the comments what you photograph. Also, when you made the switch, how much of a difference did it make?

If you haven’t, you need a new BFF and BBF is the one!

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By Jane Allan

Jane is the founder of The Lens Lounge and a professional portrait photographer living on the “sunny” south coast of England. Obsessed with light and composition. Will put her camera down to go landsailing.

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Back button focus – how to use it and why it’s your BFF