Before we discuss about the back button focus…
As we all know, the DSLR camera focuses on a particular subject when we press the shutter release button half way down and captures the frame when presses fully. But did you know that pressing the shutter release button half way down is not the only way of locking the focus using your DSLR camera?
Yes that’s true, you can allocate the focusing functionality to another button placed on the rear side of your camera and let the shutter release button do what it supposed to do i.e. to capture the image with just a click. Why let a single button perform two different functions, when you can use two different buttons to speed up the process. This can be done using the back button focus method.
What is Back Button Focus?
Back button focus method simply allows you to assign another button placed on the rear side of your camera to focus on the subject, whereas the shutter release button just captures the image when presses fully. While using the back button focus, you will witness that on pressing the shutter release button half way nothing happens, as the focusing is now controlled by another button which is controlled by your right thumb. Once your camera is set on back button focus mode, you can click multiple photos without re-focusing your subject every single time.
NOTE: Back button focus does not work on Auto mode.
Advantages of using Back Button Focus?
You must be wondering why should i use two different buttons when i can manage both focusing and exposing using the shutter release button. Well, it is completely fine to use the shutter release button for both the functions, but in some situations the back button focus can have some significant advantages.
NOTE: While using the back button focus method, the focusing mode of your camera should be set on AI Servo AF (Canon)/Continuous-Servo AF (Nikon)/Continuous AF (Sony).
With help of some examples, i would like to shed some light on the advantages of shooting using the back button focus method:
Suppose you are at a bird sanctuary with bunch of photographers waiting to witness and capture rare birds, which can make you wait for minutes. Suddenly you see a bird which appears for hardy 5 seconds and then flies away. In these 5 seconds you were only able to click 2-3 photos using the shutter release button to first focus on the bird (pressed half way) and then expose the image sensor by releasing the shutter (pressed fully). Whereas if you had used the back button focus, you could have simply locked the focus before the first shot, and then clicked multiple frames (depending on the FPS speed of your camera) using the continuous shooting mode without the camera re-focusing after every shot.
In case of a flying bird, press and hold the back button using your thumb to constantly track the bird and focus and the shutter release button to expose the frame at a faster speed. And if the bird rests on a tree, simply release the back button after locking the focus on the bird and start shooting again by pressing the shutter release button. Similarly, if a footballer player is running on the field, you can click sharp and focused image by focusing using the back button and clicking at faster rate using the shutter release button.
Thrust me, back button focus method can work wonders for wildlife and sports photographers.
Assume that you are at a beautiful location for a pre-wedding shoot. The couple is standing at a fixed spot, but regularly changing their poses. You being the photographer need to capture their memorable moments without fiddling with your camera every time you compose a shot, to check if the focus is correct. This can be annoying for the couple and can waste your precious time.
Did you realise that for the first set of shoot the distance between you and the couple was the same, but still your camera had to re-focus the subject every single time you clicked a photo. Using the back button focus, all you need to do is set the focus on your subject once before clicking the first photo and the focus gets locked. Now all you need to do is press the shutter release button fully to capture the moment ‘x’ number of times, no more re-focusing for every single click (as the camera won’t focus when the shutter release button if pressed half way).
What if you decide the go a little closer to the couple to capture a close-up shot and the distance between you and the couple reduces? No worries, all you need to do is press and hold the back button again and release it once you have locked the focus on the desired spot. Now again you can click as many frames you wish to and every single photo will be well focused and sharp.
How to activate the Back Button Focus?
To experience the benefits of the back button focus method, you need to make a small change in your camera settings. Make sure your camera is not on Auto mode, in order to access the Custom Function settings. Under the Custom Function settings, select the ‘Shutter/AE lock button’ option and then choose the option ‘AE lock/AF’ (This is how i set the back button focus on my Canon 550D, might differ on other Canon DSLR cameras). Now you are all set to set the focus using the AF-ON button using your right thumb. Sharing details of some of the Canon DSLR cameras as listed on their official website:
EOS Rebel T3 (1100D): C.Fn 7 (option 1 or 3)
EOS Rebel T3i (550D/600D): C.Fn 9 (option 1 or 3)
EOS Rebel T4i (650D): C.Fn 6 (option 1 or 3)
EOS 60D: C.Fn IV-1 (option 1, 2, 3, or 4)
EOS 7D: C.Fn IV-1 (Custom Controls — Shutter, AF-ON, AEL buttons)
EOS 6D: C.Fn III-5 (Custom Controls — Shutter, AF-ON, AEL buttons)
EOS 5D Mark II: C.Fn IV-1 (option 2 or 3)
EOS 5D Mark III: C.Fn menu screen 2 (Custom Controls — Shutter, AF-ON, AEL buttons)
EOS-1D X: C.Fn menu screen 5 (Custom Controls — Shutter, AF-ON, AEL buttons)
To activate the back button focus on a Nikon DSLR camera, click on the ‘Buttons’ options under the setup menu. Then select the ‘AE-L/AF-L button’ option to proceed and then finally select the ‘AF-ON’ from the available options.
To access the back button focus on a Sony camera simply head to the custom settings menu, select the ‘AF w/shutter’ option and turn it off.
First time i heard about the back button focus method, my reaction was ‘i am already used to click the shutter release button to focus and expose, then why use my thumb to focus separately and the shutter release button just to click photos’. But the moment i started using it practically, i was amazed by the advantages it has over the shutter release button focus. Now i can click rock band performances at much faster rate by pre-focusing my subject and capture all the expressions and moments without missing a single shot because of focusing issue.
If you are into sports, wildlife or event photography i would advise you to give this method a try and you will surely love it. In the first few days you might get annoyed as you are not used to operate the back button for focusing, but sooner or later you will fall in love with this awesome feature available in most of the DSLR and mirror less cameras.
What are your views on the back button focus? Do share them in the comments below.