Back Button Focus: How BBF will be your BFF!

1. Configure a button on the rear of the camera to trigger the auto-focusing: Most higher end cameras have an AF-ON button for this specific purpose, but if not, you can override the AEL or AF Lock buttons (these are not as useful in any case). Sony cameras have an AF-On button which is, by default, configured to do the right thing. If it’s been re-assigned to something else go to (on A7iV) Settings->Setup->Operation Customize->Custom Key/Dial Set.->Rear 1-> and choose button ‘2’. Set this to AF On. Other camera brands have a similar setup option.
2. Turn off the focussing system from the shutter-release button: This is done through your menu-system. On the Sony A7iV head to AF/MF settings->AF/MF and set option ‘AF W/ Shutter’ to off
3. Set your camera into continuous auto-focus: (AF-C on Nikon or Sony, Servo on Canon). You'll never need AF-S or Single Shot Auto-Focus (or even Manual Focus) from here on!

For other camera brands, just Google "<your camera model> back button focus" and this will give you the specific instructions. 

Now you’re ready for BBF. It will feel weird at first because the shutter-release button will NOT focus. To focus, you now press (or press and hold) the rear button to focus. When you want to take the shot, you simply press the shutter release button. By separating the focusing from the shutter release, we have MUCH more control.

In my photography workshops where we use this technique, it’s sometimes reported that the camera is not focusing. This is normal initially; the camera IS focusing, but we just need to re-wire our muscle-memory. Give it a couple of days, and you’ll never go back to using a traditional setup.

Back of the Net (I’m running out of ‘Backs' here - can you tell?)

So what are the benefits? This is best answered by some scenarios of problems with the traditional setup. They are all solved by this single button and when and how you use it, no more camera focusing configuration is ever needed.

Shooting a Landscape Photo:

Imagine the scene with the traditional setup: You’ve got your camera ready, fixed on a tripod for the slow shutter-speed shot you want. You’ve accurately focused on the point that you want to ensure front-to-back sharpness across the whole shot. You've got the shutter-release button half-pressed, you’re ready to shoot.

But wait! The composition is not correct and you’re waiting for the sunset to be perfect. So you need to get your camera and tripod moved... and wait 24 minutes for the right light.

You can’t half-press your shutter release for that long and you let go accidentally, so you have to go right back to the start again. Sure you ‘could’ use the manual focus switch on your lens, but did you touch the focus ring as you did it? You did, didn’t you? Better check, so you have to start again!

Even if you manage to take the shot, for the next shot you need to do the same thing again, because the moment you press the shutter release the next time, your camera will refocus. Back to the start each time.

With BBF, you press AF-On to get the focus you want, then let go. Now whatever you do with your camera, it will not change focus. You can get your composition correct, wait an hour, and then shoot shot after shot, all with the same focus.

You’ve effectively got yourself an option to lock focus without having to hold anything.

Shooting Pre-emptively for Action Shots:

You’re photographing a car/bike race or something with a LOT of motion. You’ve switched to AF-C mode, so that you can cope with the changing focal distance. As them come past you you need to half-press your shutter release button and track them to keep them in focus. You might get a good shot, but careful composition is going to be impossible.

With BBF, you simply focus your camera on where you know the competitors WILL be, get focus and then let go of the AF-On button. Get your composition as you want it and now you just sit and wait for the perfect moment. As they come past, burst mode and you have 100 shots all in focus.

A few pictures with movement or elements that would be almost impossible to capture without BBF.

So if you’re using AF-S and AF-C at different times, or are using AF-Hold (with a button or half-press of shutter) or switching to manual focus to lock in the perfect focus distance, then this is going to be a game-changer. If you’re not doing either of those things, then you should be, and then you’ll benefit from BFF.

My Ideal Setup

I use Back-Button Focusing on the AF-On button and EyeAF on the AEL button and never need to change my focusing setup. It’s the perfect combination of using the camera’s intelligence to find the subjects eye, while giving me the option of taking full and flexible control of focusing in an instant.

If you rely heavily on AI focus modes such as object tracking, or you tap your rear screen to focus, then you are probably the only category of people that will not see any benefit of BFF. But even in these cases, those modes do go wrong sometimes, and this is why I never use these modes for my commercial work. When it does go wrong, you need to be able to control your camera's focusing and BBF lets you do that perfectly.