Focusing with Back Button Focus

Back Button Focus, often abbreviated to BBF, is an alternative to focusing with the shutter-release button. On most modern cameras, autofocus is activated when you press the shutter button halfway. The shutter button therefore has two functions: focusing and taking the picture.

With Back Button Focus, these two functions are separated. You use a button on the back of the camera to focus and the shutter button only to take the picture. Many DSLR and mirrorless cameras allow you to configure the controls in this way.

Why use two buttons when one button can perform both functions? Back Button Focus can be particularly useful when photographing fast-moving subjects.

Advantages of Back Button Focus

An important advantage of BBF is that it gives you more control over when autofocus is active. When continuous autofocus is selected, you can track a moving subject by holding down the rear AF button and stop focusing simply by releasing it.

Focusing and releasing the shutter are independent of each other, allowing you to concentrate more easily on the subject, composition and decisive moment.

Disadvantages of Back Button Focus

The main disadvantage is that you have to get used to a different way of operating the camera. You use your thumb to focus and your index finger to press the shutter button.

This may feel unnatural at first, but it usually becomes familiar quite quickly. Depending on the camera body and the way you hold it, the position of the rear AF button may also be less comfortable for some photographers.

How do you set up Back Button Focus?

As the name suggests, Back Button Focus assigns autofocus to a button on the back of the camera instead of the shutter-release button.

You normally configure this through the camera menu. Assign autofocus to a rear button such as AF-ON and disable autofocus activation from the half-pressed shutter button.

The exact procedure varies between camera brands and models. Consult your camera manual or the manufacturer's instructions for the correct settings for your model.

Once Back Button Focus has been configured, use the rear AF button to focus and the shutter button to take the picture. If you later want to return to conventional shutter-button focusing, you will need to change the settings again.

How does Back Button Focus work?

Back Button Focus is often used for sports, wildlife and other situations in which the subject is moving continuously.

For a stationary subject, you can press the rear button to focus and then release it. The focus remains at that distance while you take one or more photographs, provided the subject-to-camera distance does not change.

For a moving subject, you can use continuous autofocus and keep the rear AF button pressed while following the subject. This gives you direct control over when autofocus starts and stops.

Back Button Focus for sports photography

In sports photography, a subject can move quickly through the frame. Back Button Focus allows you to control autofocus and shutter release independently.

With continuous autofocus selected, keep the rear AF button pressed while tracking the athlete. You can then take individual photographs or a burst of images with the shutter button while autofocus continues to track the subject.

This can be particularly useful when following unpredictable movement and waiting for exactly the right moment to take the picture.

Tip: practise using Back Button Focus before relying on it during an important photo session. It takes some getting used to, but it can become a natural and efficient way of operating your camera.