Understanding the capabilities of the camera is important to an efficient photography workflow. It is tempting to think of the idea of point>focus>shoot as the simplest and most efficient way of working. But this isn’t necessarily the case. Modern cameras include many functions and options that might surprise you with new methods of working with your camera. If you’ve spent time researching cameras and photography you may have come across the term “back button focus”, without getting a clear idea of what it is and why it might be useful to you. This article will demystify back button focus, help you decide if it might be useful to you, and instruct on how to use back button focus on the Fujifilm X-T2.
WHAT IS BACK BUTTON FOCUS?
Back button focus removes the job of focus from the shutter button. Any camera geared toward professional or advanced amateur use includes a way to achieve back button focus. Often, the job of focus will be taken over by the AF-L or AF-ON button on the back of the camera. The function of the AF-L or AF-ON button can usually be customized. You may need to set up that on pressing the AF-L or AF-ON button the camera will focus and disable the shutter for focusing. After releasing the AF-L button, the focus will be locked on the subject. Now pressing the shutter button will only release the shutter and take the photograph without re-focusing.
Essentially it is a single setting that does two jobs. Once you have learned to use it effectively you are prepared for a variety of subjects without having to change AF settings.
WHAT IS BACK BUTTON FOCUS GOOD FOR?
Removing the job of focus from the shutter button can allow for gains in speed and efficiency in some situations. Back button focus gives you the advantages of single focus and continuous focus without changing settings or risking a misfocus. Let’s consider two use cases.
Portraits – When photographing a portrait subject a photographer will often want to make several exposures with the same framing but altering the pose or angle. Using back button focus she can focus once and then take all the photos necessary with focus locked in. As long as the distance between the camera and subject does not change focus is a certainty. It eliminates the need to maintain a half-press of the shutter or to focus and recompose several times. The photographer is still required to take care when working at shallow depth-of-field. It is not the only way to get the job done, but it is highly efficient.
Switching Between Static and Moving Subjects – Imagine shooting a wedding. You’re in position before the bridal march begins and take a few shots of the groom who stands at the altar. Back button focus means you have locked focus on the groom and can catch every expression he goes through with re-focusing every shot or keeping a half-press of the shutter. Then a flower girl walks down the aisle, and you press and hold the AF-L button. Now you are in continuous focus and tracking her progress.
WHY NOT JUST CONTINUOUS FOCUS AND SHUTTER HALF-PRESS?
Sure, you could use continuous focus and a half-press of the shutter. However, that would mean the camera would always be in continuous focus, even when it might cause you to lose focus. And of course, anytime you fully release the shutter focus is lost, unlike back button focusing. If anything else enters the frame, the continuous focus can try to shift focus to the new subject. Back button focus will not.
As long as you keep the focus point centered on the subject back button focus will maintain it even if something else enters the frame. It is not exactly like tracking but can be used effectively.
SETTING UP BACK BUTTON FOCUS ON THE FUJIFILM X-T2
Enabling back button focus on the Fujifilm XT-2 required changing a few settings in the menu.
Access the Menu;
- SETUP >BUTTON/DIAL SETTING
- BUTTON/DIAL SETTING>Fn/AE-L/AF-L BUTTON SETTING
- ASSIGN “AF-ON” TO THE AF-L BUTTON IF IT ISN’T ALREADY
Next, it will be necessary to remove focus from the shutter button by accessing the menu;
- SETUP>SHUTTER AF>OFF
With the above settings assigned, you can now press the AF-L button to focus, release it to lock focus, and press the shutter button to make as many exposures as necessary. For moving subjects, a continued press of the AF-L button will engage.
Using back button focus is very useful with continuous autofocus engaged. Helpfully, continuously pressing the AF-L button will engage continuous focus and track moving subjects under the focus point. On the Fujifilm X-T2 at least, back button focus works just fine when moving the focus point with the joystick.
Back button focus can be a useful technique when focusing needs change quickly. Wedding and event photographers might find it useful to not have to think about their focus settings by leaving the camera in continuous focus. Locking focus can free you up to concentrate on other aspects of the photo. Remembering single press for stationary, and continued press for moving subjects can mean less fiddling with setting when you should be taking photos. Whether you come to use back button focus or find it too much of a hassle, it can not hurt to consider it as one of many tools in your photography kit.