There are still many people that have not heard of back button focusing, and of those that have there are many who are not entirely sure of its benefits. For me, using the back button focus is a real game changer in all all types of photography but especially for sports and wildlife.
Canon cameras have the equivalent of One-Shot or AI-Servo modes. For Nikon users, you can shoot in AF-Single (AF-S) or AF-Continuous (AF-C). Those using One-Shot and AF-S modes mean that your camera focusses at the point you half-press the shutter button. If your subject moves (which is guaranteed to happen at some point with wildlife) you have to release and repress the button to focus again. As a result, most photographers will find themselves looking away from the viewfinder to change between the two modes depending on the type of scene they are shooting. This is precious time, and can often result in missing shots.
Back button focusing allows you to separate the focusing action from the shutter button. So instead you press when you wish to focus. This allows you to your shots like in One-Shot or AF-S.
Here’s an example of using the AI Servo to lock focus and recompose:
Whilst photographing this great grey owl perched in the tree, I was using back button focusing. I pointed the chosen focal point (the center point, as it is most accurate) at the owl and pressed AF-On to focus. Then, having released AF-On, I was able to recompose the shot and press the shutter to take the image. All the time in AI Servo mode!
Here’s an example of using Back Button Focus along with AI Servo to track the subject:
Are you more into action photography? Then the biggest advantage of using back button focus is for you. Each time you have a moving subject you just need to simply press and hold the AF-On button and follow the subject while in AI Servo mode. The camera's AF system will do it's best to track the subject allowing you to concentrate on pressing the shutter button to capture the image while everything is happening quickly right in front of you. There are many advancement to AF tracking, especially in the newer cameras. Canon, for one, offers adjustments case settings which help the AF system track more effectively.
Florida Getaway 2016-052
There are other reasons why you should make the change, too. You’ll . Just don’t press AF-On, manually focus the lens with the focus ring, then press the shutter, and your adjustments aren’t altered. It will not make any adjustments to the focus until you press the AF -On again.
Making the Switch
I imagine that by now you have decided you want to make the switch – at least just to try it out.
For Canon Users
Go to your menu and head to . Select the shutter button, and change its function to . Then change the function of AF-On button to .
For Nikon Users
Go to your menu, and enter the custom menu. Scroll down to and switch it to .
Some older Nikon camera users will find this under the option.
Still not sure and want to see it in action then watch this video by Tony Northrup as he explains it in more detail
Life is short... so go make some images to remember the journey along the way!