Back Button Focus – What it is and why you might want to use it

Yes, we’re bringing up the back button focus. This is one of those things that regularly seems to split the camera-owning public. One side swears by it, and the other side can’t stand it or just doesn’t see the point. But, like many things in photography, it’s just another way of doing something. In this case, focusing your lens.

In this article, we’ll deal with this concept, going through all the specifics, from setting it up to when (not) to use it.

In the video above, photographer Pierre Lambert looks at what back button focus is and when it might be beneficial to use it. He also looks at when it may be more beneficial to do things the old-fashioned way with a half-press of the shutter.

What is the back button focus?

So, what is the back button focus? Well, it’s like it sounds. You’re using a button on the back of your camera to focus instead of a half-press of the shutter. Physically, you’re using your thumb for autofocus and your index finger to take the photo. It disconnects the camera’s autofocus system from your shutter completely.

Using back button focus by default can offer many advantages depending on your shoot workflow. However, it isn’t always the best solution for everybody, and we’ll discuss both scenarios.

Finding it on your camera

Advanced cameras often boast a dedicated AF-ON button, streamlining focus control. Mid-range options, however, require customization. Let’s explore both scenarios, starting with dedicated buttons. I’ll give you examples of Nikon cameras because that’s what I’m best familiar with, but the concept for setting custom controls is similar for other brands. You can always refer to your camera’s user manual for your particular case.

Setting a dedicated AF-ON button (e.g., Nikon D500):

• Choose AF-C Focus Mode: Activate continuous autofocus (AF-C) for continuous subject tracking.
• Select Focus Area: Opt for a dynamic option like “group” or “D25” for flexible focus points.
• Enable AF-ON Focus: Access the Custom Setting Menu > Autofocus > AF-activation and select “AF-ON only.” This separates focus initiation from the shutter button, allowing independent control.

Now, let’s move on to a mid-range camera. In this case, we have to customize the back-button autofocus. We’ll set up the AE/AF button, which locks both focus and exposure by default. However, we’ll perform some custom key settings of the AE-L/AF-L button.

Customizing the AF/AE Lock button (e.g., Nikon D7100)

• Set the focusing mode to AF-C (continuous autofocus)
• Select the focus area as D9 or D21 (dynamic)
• Go to Menu > Custom Setting > Controls > Assign AE-L /AF-L button > select AF-ON.

For Canon cameras, press one of two buttons on the rear to activate the Back-button AF. You can customize your camera’s settings to apply AF activation to one of these two buttons by using a Custom Function. For cameras with separate AF-ON button, there is also a Custom Function. It allows you to switch the roles of the AF-ON button and the adjacent AE-L button.

Remember, this process may differ depending on your camera brand. Still, this process should be relatively similar for Fuji or Sony cameras, and other brands; both DSLR and mirrorless. You can always consult the user manual for specific instructions regarding your camera’s setup menu.

When is the back button focusing a good idea?

Whether back button focusing is your cup of tea or not, you can’t deny its usefulness in many situations. For example, back button focus can be fantastic if you regularly shoot products. You just hit the button, it focuses, and then you don’t have to worry about it shifting between shots. It’s almost irreplaceable when the camera is locked off on a tripod for shooting timelapse. It’s a lot less hassle than flicking between autofocus and manual focus. Essentially, it works for any other situations you don’t want the focus to change.

Many photographers I know also use it for portraits, landscape photography, food photography, and architecture. Generally speaking, it works well for slower-paced situations. This focus type can be your best friend when you have enough time to set the framing and composition.

Some photographers use back button focus even for fast-paced shooting scenarios. For example, wildlife. Back button focus can be helpful when an object in the foreground partially blocks the subject. It can be grass, branches, rocks, or trees. By using back button focus, you can adjust the lens’s focus ring without worrying about the camera’s autofocus system overriding your adjustments.

Another advantage is that back button focusing helps you switch between AF-C and AF-S without changing focus mode. This allows for quicker reaction time when photographing fast-moving subjects.

When should you rely on the shutter release button?

However, I think that back button focusing and unpredictable subjects aren’t for everyone. Shooting things like wildlife, sports, or car races is better off with the shutter button. Otherwise, you could miss the shot entirely as your subject drifts through the plane of focus. Or, you have to contort your hand to autofocus and shoot simultaneously. This compromises the steadiness of your grip on the camera.

Personal experience

I’ve given back button focus a serious try on various occasions. However, it just doesn’t offer me any benefit over the half-press of the shutter for what I shoot and how I shoot it. But, I’ve always shot Nikon as my primary system, and most of those bodies have both a dedicated AF-ON button and an AF-Lock, aka AF-L button, on the back of the camera. Even my old film bodies do!

I tend to want autofocus more often than I don’t, and when I don’t, I can just hit the AF-L to stop it looking and just take a shot (essentially the same effect as using BBF). And several of my lenses, like the Nikon 70-200mm f/2.8VR, have AF Lock buttons on the lens itself if I want to shoot without having the camera autofocus. So, BBF has mostly been a redundant technique for my needs.

But for you and your needs, back button focusing might just prove to be advantageous.

Whether you love it or hate it, or maybe you’ll just use it for specific things, it’s worth giving it a try. It might help, it might not, but what does it cost you other than a little of your time?

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