I want to tell you all a secret. This was literally the biggest ‘lightbulb’ moment for me on my journey so far. It was also the biggest game changer for obtaining that sharpness that photographers crave. It’s called back button focus! In this post, I’m going to share why back button focus (BBF) is my BFF!
Back button focus (in case you’ve never heard of it) is literally a different method of focusing on the subject. It totally separates the two actions (focusing and operating the shutter to capture the image) from each other into two separate steps. This may sound tricky. And it really does take some getting used to in the beginning. Muscle memory and learned behavior is strongly in play. This is especially true if you’ve been shooting a certain way for a long time. But trust me guys, you will never look back. After a few weeks, I actually find it odd shooting the ‘old’ way now!
The main advantage for me is SPEED. Toddlers are THE fastest land mammal (especially when you ask them “What’s that in your mouth?” Usually it’s a day old piece of toast they hid down the back of the sofa or a random Haribo they found on the floor at the park. Obtaining (and maintaining) focus can be really tricky. Yet accurate focus is one of the most critical parts of the storytelling aspect of photography. I have to say that by using BBF, about 95% of my images are PIN SHARP now. Not all beautiful and print worthy of course. But they ARE sharp! This is thanks to BBF.
When you take a photograph using the shutter button alone, you half press the shutter button which engages the camera’s auto focus. You can then re-compose (if needed). Next, you fully press the shutter button to actually take the image. This is fine for a non-moving subject or compliant model. You CAN switch focus modes to track your subject better, but it can have it’s draw backs. My main issue was that I sometimes accidentally pressed the shutter before I was ready. Or sometimes I was in the wrong camera mode (more on that later.) Sometimes, I might misjudge it and press too late. My focus was always just a bit off and I couldn’t understand why.
I also found it really irritating that you simply have ONE SHOT at the photograph before you have to start all over again because the shutter button has been pressed the auto-focus is now dis-engaged. This isn’t great for photos of action where it is hard to regain that focal point in just the the right place while they are jumping off the bed or riding their bike full speed towards you – whilst of course you are lying on the floor wearing your new jeans to get the right angle for the latest mini-shoot you are working on.
However, when you take a photo using your BBF, you are actually going to be using two separate buttons to capture the image.
The name suggests that it needs to be a button on the back of your camera that you would use. But, as long as your camera menu allows, you can actually assign any button you like to be the focus button. Most cameras have a button called ‘AF-ON’ or something similar. Mine is called AE-L/AF-L and that is the one I use to be my BBF. When I take my image I ‘lock on’ to my subject with my BBF. This will literally hold the focus on that subject while you use the shutter button to capture the frame.
In order to track your subject when they are moving, we need to make the camera work a little harder and change our focus mode from One Shot/AF-S into AI Servo/AF-C. This can mean going through complicated menu and means we sometimes lose our ‘perfect moment’ when a stationary subject suddenly becomes a moving subject. Also, even with a stationary subject, the camera is trying to make little micro-adjustments all the time to pick up the focus (it’s trying really hard to read your mind and produce the image you are after). All of this means there is lots of room for error.
Now for the magic… BBF will become your BFF!!! By moving the focus and capture to two separate buttons, it means that you can actually obtain focus JUST ONCE and then literally just keep pressing the shutter button again and again whilst moving with your subject (almost like a manual version of burst mode). Whether its side to side or motion where they are gaining or losing distance – every image will be sharp! You can take a series of photos, which capture the whole range of movements in one single attempt!
In this photograph, I asked my son to stand right next to me and get ready to run while I ‘locked focus’ using my BBF. I then shouted “GO” and snapped the shutter button again and again (keeping my finger on the BBF) and whilst he ran away from me. All of the images in the series were sharp. All I had to do was pick the composition I liked best. There would be no way to achieve this using the shutter only method. It would have been really difficult to re-gain focus again whilst he was on the move. Especially with him bouncing all over like a drunken kangaroo!
I also use my BBF whilst shooting my tabletop scenes. I place my focus where I want it to be, hold down my BBF and then reach the camera above my head while I snap the shot. This allows me to get a much wider angle shot with my 28mm lens.
Another BIG advantage is that the cameras auto focus with STOP searching for focus when you remove your finger from the button. This means that if you want to quickly move to manual focus (I’m thinking of all those lovely self portraits with your camera on a tripod), and want to take a few frames without the button pressed (maybe your subject is moving through long grass and you don’t want the auto focus to randomly keep picking up the grass). It means you can quickly begin to use manual focus without changing any camera settings. In a similar way, you can take your finger off the BBF for a few seconds while you take another few frames focused on your subject, rather than picking up on the grass etc.
Well, honestly, after the initial steep learning curve and learning to co-ordinate my fat fingers with a manual dexterity I do not normally possess, I can seriously say that I have found NO drawbacks. Some people say that they find it difficult to coordiante the two in extreme weather conditions (when there fingers are numb from the cold or sweating in the summer). But to be honest, if it really is THAT cold – chances are that my Wildlings will have insisted we return home for hot chocolate and marshmallows LONG before that becomes a problem!
I have put together a basic set-up for each of the common camera brands below. What you are essentially doing here is TWO things; de-activating your shutter release button from having focus ability and then assigning and activating a different button to do that job.
NOTE: Some models do not have an AF-ON button (like my D750). In this case, you also need to set up the AE-L/AF-L button to be assigned to the task of auto focus by doing the following steps:
OR IN SOME MODELS
If you do not see your camera there or have any difficulty at all, please give us a shout over on the Hello Storyteller Facebook or Instagram page or you can find me on Instagram! You may even find your equipment twin! This helped me so much when i was starting out.
I can’t wait to hear your thoughts on Back Button Focus! For me, it was a serious GAME CHANGER!!!