Why You Need to Try Back Button Focus

During my life as a photographer, there’s been a few techniques I’ve learnt that have revolutionised the way I shoot. First was full mastering manual control, then later came understanding how to utilise flash properly and off-camera lighting. Over the last few years, I hadn’t picked up any transformative skills and began to think that I had learnt all the key things to know. That was until about six months ago when I decided to try back button focusing, and I wish I made this simple switch much sooner.


Using back button focusing has transformed how I shoot

For the first eleven and a half years of my photographic life, I set the focus using the same technique as the vast majority of photographers, and it’s most likely the same method you use. I’d move my active AF point over the area I wanted to set the focus, half press the shutter button to set and lock the focus, then adjust my composition before fully pressing the shutter button to take the shot. I’m sure it sounds very familiar.

However, while this is the default way manufacturers set up cameras to operate, you can actually disable the autofocus from the shutter release, and switch it exclusively to a button on the back of the camera. This means you’ll need to press your thumb to activate the focus, and your index finger is only responsible for taking the shot.

But why would you want to do that? It sounds more complicated and cumbersome, and the technique you’ve always used works just fine, doesn’t it? That’s what I thought when I first considered trialling back button focus, and I was sceptical I would find any benefits of setting the focus this way.

Six months on from my first ventures with back button focusing, and I’ve never once considered reassigning the focus to the shutter release button. My shooting is faster, simpler and more flexible than before, and it’s no exaggeration to say it has revolutionised the way I take pictures.

Simplify your camera setup

Using back button focus means I no longer need to switch AF modes to match different subjects; you have Single (One Shot/AF-S), Continuous (AI Servo/AF-C) and Manual focus available all at once. This makes it quicker to switch between subjects and simplifies my camera setup, freeing up more energy to concentrate on my composition and the subject.


You’ll need to set your camera to its continuous focusing mode

Shoot faster

The biggest time saver with back button focusing is that it eradicated the need to refocus every time you lift your finger from the shutter button. With a traditional setup, if you’re using Single focus or your finger strays from the half-press position, then you need to reset the focus before you next take a shot. This can be both time consuming and frustrating, and the extra delay might mean you miss a key moment. It’s also often pointless. If you’ve previously set the focus accurately – and the distance between your lens and subject hasn’t altered – then why the need to let your camera confirm focus before taking the frame. With back button focusing, as soon as you press the shutter button the camera takes a shot without focusing; there’s no delay.

Compose more easily

Another big benefit of shooting with back button focus is that it allows you to be more free and flexible with your compositions. With shutter button focus you might adjust the active AF point to rest over the area in the frame you want to be rendered sharpest. Most DSLRs only offer focus points in the central portion of the frame, and hopping the AF point to different positions also slows you down. With back button focus you can use your camera’s central AF point, which tends to be the fastest and most accurate focus sensor, and eliminates the need to fiddle with focus points. As soon as the focus is set via the back button, it stays locked to that distance so you can fine tune your composition and switch it up between shots, allowing for faster and more flexible creativity.

To use back button focus, your camera needs to be in its Continuous focusing mode (AI Servo on Canon, AF-C on most other brands), and you also need to disable the focus from the shutter button, and assign it to the AF-ON button on the back of your camera. If your camera doesn’t have one of these buttons, most models allow you to reassign a Function button for this operation (you might need to dig out your manual).

To set up back button focus on a Nikon DSLR all you need to do is open up the Autofocus menu, select AF Activation and then change it from Shutter/AF-ON to AF-ON only. On a Canon you need to open the Custom Function III menu, and then find the page with the custom controls. First off disable the autofocus from the shutter button by turning off ‘AF start’ and set it to AE-Lock, then just select the AF-ON button and assign it to autofocus. Some models can vary so you might need to check your manual or have a play around.


On a Nikon set AF activation to AF-ON only to use back button focus

You’re now set up with back button focusing, so if you don’t press the AF-ON button to activate the focus before shooting, your camera acts as if it is in manual focus mode. The focus remains locked as the distance it was last set to, and you can take manual control by adjusting the focus ring on your lens. If you’re shooting a static subject, like a landscape or portrait, simply press the AF-ON button to set the focus where you want it, then release your thumb from the focus. You are now free to shoot and there’s no need to set the focus again unless the distance alters. For moving subjects like sports or wildlife, all you need to do is to keep the AF-ON button held down with your thumb to use continuous autofocus. Your camera will continue to track the subject, and your index finger is just responsible for firing the shutter whenever you want to take a shot.


Setting the focus with the AF-ON button speeds up the shooting process

This setup makes shooting more versatile. Imagine you’re taking a dog’s portrait, and it’s obediently sat there posing. You’ll focus once on the dog’s eyes, then disengage the focus while you try out various compositions and take lots of frames. Suddenly, the dog takes to its feet and starts walking towards you. All you need to do is hold your thumb on the AF-ON button to begin using continuous focus and carry on shooting. There’s no need to switch AF modes and there’s fewer processes to slow you down.


Using back button focus helps you set a sharp focus more quickly

Shooting this way might take a little bit of getting used to. I was slightly nervous about using it at first, fearing I wouldn’t focus correctly before shooting, rendering the image useless. But in truth after a couple of outings using back button focus became just as normal as half pressing the shutter button, and brought about the worthwhile benefits that have improved my photography. I urge you to try it, and I’m confident that like me, you’ll wished you’d have moved over to this way of shooting a long time ago.