There are things that we use every day that we wonder how we would have ever survived without them. Sliced bread and buttons come to mind. And can you imagine working on a computer without a mouse? For many photographers, back button focus falls into this category too.
Back button focus is one of those things that takes a little getting used to but once you’ve mastered it, you can’t imagine ever going back to focusing with the shutter button again.
For this shot, the depth of field was critical so I couldn’t have the camera try to refocus between every shot. Back button focus made it easy to focus on my predetermined mark and then maintain that focus through a series of shots.
What’s the Big Deal?
On most DSLR cameras, by default, when you press the shutter release button part way you activate the focusing system. This is when the servos in your lens zip in and out attempting to focus on your subject. Now auto focus is a huge topic on it’s own and this is not the time or place to discuss such a complex system. For our purposes, just know that, by default, every time you press the shutter button, you are also activating the focusing system.
For a lot of photos, that’s fine. But there are many times I would like to set the focus and then not worry about it for each frame that I shoot. Sometimes the subject is somewhat small or is very close to other foreground elements. When you use the shutter button, it’s so easy for the focus to grab hold of a foreground or background subject. Not a problem once, but if you’re shooting multiple frames, it can be a real pain.
Some photographers like not having to choose between single and continuous focus and with back button focus you don’t have to. Just leave continuous autofocus selected and control when it’s used with the back button.
Now, we could go on an on with the benefits of back button focus but it’s one of those things you just have to try. It’s going to be awkward in the beginning. You’re learning a new skill and making a fundamental change in the way you use your camera. But I will guarantee that if you give back button focusing a chance. Get used to how it works. You’ll never go back to focusing with the shutter release again.
Setting Up Back Button Focusing
Back button focusing is simply a matter of setting menu options in your camera. Each camera brand and model has it’s own menu options so check out the user manual for your camera. But don’t look for “back button focus”. It may not be listed like that in your manual.
Setting up a camera for back button focusing is simply a case of reassigning the function of a button on your camera. You basically want to tell your camera that you no longer want to use the shutter button to activate focus - instead you want to assign that function to another button on the back of the camera. For my Canon 5D, I’ve assigned focus to the “*” button.
For Canon users it’s part of the Custom Function menu. That’s the orange colored options - the icon looks like a camera with a set of vertical lines below it. Go to the third panel in the orange custom functions menu and then select Custom Controls. The terminology is C.Fn3 - Display Operation options.
For Nikon users, select your custom settings menu - it has the pencil icon - and then select Autofocus. Then set AF activation to AF-ON only. If your Nikon doesn’t have a AF button, then you’ll have to use a different button. Check your user guide and any Nikon resources on how to set your specific camera model.
Practice, Practice, Practice
Don’t set this up right before you begin an important photography session. It’s going to feel awkward. You’re going to miss some shots. You need to practice. Set some time aside to practice and then set up your camera for back button focus. Then go out and practice. Shoot a few hundred frames. Challenge yourself. Shoot a subject through some foreground bushes.
In time you’ll be comfortable with it and in no time you’ll wonder how you ever shot without back button focus. It’s a game changer.