Why You Should Use Back Button Focus In Motorsport Photography
Nailing focus on something moving in excess of 200km/h (that’s 125mph for those American readers) is tough. So as a motorsport photographer, you need to use all the tools at your disposal to ensure crisp, sharp photos each and every time. One of those key tools is back button focus.
Trust me, even the best sports cameras available today with the most advanced autofocus systems could use a little help to ensure you get a pin-sharp photo each and every time you are trackside.
So let’s have a look at what back button focus is, how it works and how you can set it up on your camera to see if it benefits your motorsport photography.
So What Is Back Button Focus?
Back button focus is a simple technique of reconfiguring the buttons on your camera to separate the focusing from the shutter so you are able to apply them individually.
By default, all digital cameras are set up so that a half-press of the shutter button triggers the auto-focus system before a full press to take the actual photo. No doubt something you are very familiar with.
However, in DLSR and Mirrorless cameras, you can change the button configuration to use one of the buttons on the back of the camera to focus instead. This method is known as back button focus.
This is achieved by changing the settings in your camera and allocating the autofocus function to a separate button on the back of the camera.
On Canon, Nikon and Sony cameras, this is achieved by reconfiguring the AF-On button. However, the process varies from manufacturer to manufacturer. We’ll dig into that shortly.
What Is The Problem With Having The Shutter Button Do Both Jobs?
There are a number of reasons why having the shutter button do all the work isn’t ideal. The first is being able to pre-focus.
In the high-speed, action-packed world of motorsport, things happen quick. Like, really quick! To maximise the likelihood of getting sharp in focus shots of a particular section of the track, you can pre-focus so the camera doesn’t need to hunt to find its target.
Secondly, there are times when we don’t want the camera to be adjusting focus continuously, particularly while taking panning shots. If you have configured your auto-focus servo mode (or continuous auto-focus, more on that here) and have your aperture nice and narrow for that longer exposure effect for motion blur, the auto-focus system might be doing a lot of extra work unnecessarily.
While panning, pre-focus on the racing line, where you know the race cars are going to be, and then focus your attention on using a smooth motion to get clean, crisp shots and not bumping around the camera by pushing different buttons.
Especially when going for those particularly cool panning shots where you are shooting through an element of the scene, like the crowd, a tree, or even just a fence, that can easily cause auto-focus to re-adjust.
I’ll write up a separate post on how to master the panning technique; watch this space.
Using Back Button Focus To Improve Composition
Admittedly this is becoming less of an issue now that the most recent mirrorless camera now offer nearly 100% focus coverage.
However, on the older DSLRs – even the top-tier ones – focus points were heavily centred in the middle of the frame. And if you know anything about good photography composition, having your subject in the dead centre of the frame rarely makes for an interesting photo, especially in motorsport photography.
Being able to preset your focus and then re-compose your photo, even in the high-paced world of motorsport, really helps make the resulting photo much more dynamic.
Are There Any Drawbacks To Using Back Button Focus?
Switching to back button focus takes a little getting used to. As such, I have it set up on all of my cameras. Even ones I wouldn’t necessarily use at the track. It’s a rhythm and a feel thing.
In fact, these days, if someone hands me their camera, I’m so in tune with pushing the AF-On button to trigger auto-focus that it takes me a couple of seconds to remember the regular way of using the focusing. And on the flip side of that, if I hand my camera to someone else to take a photo, it will most certainly be out of focus because they don’t know to push the AF-On button.
So, with that in mind, if you don’t get it straight away, don’t get too concerned. It will take a bit of practice until it becomes natural.
Just make sure that you give yourself time to adjust so that it won’t impact your ability to get sharp photos on paid gigs.
How To Set Up Back Button Focus On Canon Cameras
To set up back button focus on a Canon camera, you need to adjust the button configuration slightly. To do this, you need to go into the camera’s menu.
Within the menu, you need to navigate to the Custom Functions menu (the brown/orange one signified by the camera with the lines underneath) and look for the Custom Buttons (Mirrorless) or Custom Controls (DSLR) options.
Once you are in the Custom Buttons/Custom Controls menu, the display will walk you through what the buttons are on your particular camera and how they are configured. To configure back button focus, we need to change two of them.
Firstly, the Shutter button. Which should be the first button selected when you enter this menu screen. We want to do is go into the shutter button configuration by pressing the Set button to change the half-press setting from Metering and AF Start to just Metering Start and press the Set button to lock in the change. This will stop the auto-focus system from being triggered by a half-press of the shutter.
The next step is to configure the AF-On button to trigger the auto-focus. To do this, use the camera wheel to scroll down until you get to the AF-On configuration and press the Set button to go into these settings. Within this part of the menu, you will notice a lot more options, but what you want to do is select the Metering and AF Start option (you’ll recognise the icon from the Shutter button menu earlier) and then press Set to lock in the change.
To confirm the changes have been applied, set up your camera with a wide aperture and then test out the AF-On button and half-pressing the shutter button to see what activates the auto-focus system.
How To Set Up Back Button Focus On Nikon Cameras
To configure back button focus on Nikon cameras, you are ultimately looking to do the same thing as on a Canon; just where these options are placed in the menu and how they are named are slightly different, even across different Nikon models.
Within the menu, you need to navigate down to the Custom Setting Menu (the red one signified by the pencil icon) and look for the A | Autofocus options.
Press the Ok button to enter the Autofocus options; you want to look for AF Activation and press the Ok button again to enter this sub-menu. This is where you can choose to either have auto-focus activate on both a press of the shutter and AF-On (Shutter/AF-ON) button or just the AF-On (AF-ON only) button on its own.
To make the best use of the back button focus feature, you want to set this to AF-ON only and press Ok to lock in the change. You might notice that the AF Activation changes to off; this is correct; auto-focus will only trigger when the AF-On button is pressed.
To confirm that the AF-On button is configured to trigger the auto-focus system, within the Custom Setting Menu again, this time scroll down the menu to F | Controls.
Again press Ok to enter the Controls menu and scroll down to Custom Controls (Mirrorless) or Custom Control Assignment (DSLR). This sub-menu is similar to the Canon one, where it shows you the camera’s button layout and how those buttons are configured. You want to scroll down until you get to the AF-On button and press Ok to adjust these settings.
Within the AF-On button settings, you’ll be presented with a bunch of different options, but what you need to do is make sure it is configured as AF-On. Press Ok to lock in these settings.
If your Nikon camera has an AE-L/AF-L button (typically on the lower-end Nikon DSLRs) instead of an AF-On button, the process is slightly different. You need to go into the F | Controls menu, but this time scroll down until you see the Assign AE-L/AF-L button settings.
Press Ok to enter these options, and you will be presented with two configurations: Press and Press + Command Dials.
For back button focus, all you need to do is change the Press configuration to be AF-On. This will change the AE-L/AF-L from an exposure and focus lock button to an AF-On button, as we’ve previously talked about.
To confirm the changes have been applied, set up your camera with a wide aperture and then test out the AF-On (or AE-L/AF-L) button and half-pressing the shutter button to see what activates the auto-focus system.
In the event that you find that your camera won’t take a photo unless you have the AF-On button pressed, you might need to check your AF-C Priority Selection settings. More details on that are here.
How To Set Up Back Button Focus On Sony Cameras
Now for Sony cameras, I’ve only tested configuring back button focus on the top-tier Alpha series cameras, the A7, A9 series etc. I’ve been told the settings are similar for other Sony mirrorless cameras, but I haven’t had a chance to test them.
On the Sony, you need to change one setting and check another to ensure back button focus works ideally.
In the menu, go to Camera Settings 1 (the red one signified by the camera icon with the number 1 next to it) and look for the the AF w/ shutter option. Typically this is on menu page (AF2) 6/14, but that might not be the case on all Sony models.
By default, AF w/ shutter will be set to On, which will activate auto-focus with a half-press of the shutter. To take full advantage of back button focus, we want to change this to Off.
Now, when configuring the back button on the camera to engage auto-focus on Sony cameras, you have two options – either the AF-On button or the AEL button. This might take a little testing to find out which suits you and your thumb placement on the back of the camera better.
To adjust these settings, you need to go into Camera Settings 2 (the purple one signified by the camera icon with the number 2 next to it) and scroll until you find the Custom Key options. Typically this is on menu page (Custom Operation1) 8/9, but again that might not be the case on all Sony models.
Here you will find 3 different Custom Key options, one for photo/still image (the landscape icon), one for video/movie (the film icon) and one for playback (the one with the play button icon). While you don’t have to, I would change the photo and video settings to match so you don’t catch yourself out later.
In the Custom Key options, you are looking for either the AF-On or AEL (or both, up to you). By default, AF-On should be set to AF-On and will work the same as I outlined in the Canon and Nikon sections. You can also choose to change the AEL button from Auto Exposure Lock to AF-On as well or instead.
To confirm the changes have been applied, set up your camera with a wide aperture and then test out the AF-On (or AEL) button and half-pressing the shutter button to see what activates the auto-focus system.
If you have any issues with finding any of these settings, consult your camera manual. And if you would like more details on how you can fine-tune your auto-focus for better results, visit this post.
Back button focus can be an extremely valuable tool in ensuring that you nail the focus on your motorsport photos each and every time. Just make sure you give yourself time to adjust to the feel of how it works in your hand before trying it out at the track.
I've been working as a motorsport photographer in Australia since 2012, building up my business InSyde Media. I am very fortunate that I have been able to work at all sorts of motorsport events including Supercars, F1 and WRC all over Australia and New Zealand. Also, check out my personal website where I document my travels and a few other things.
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