TECHNIQUES
Back button focusing
Speed up your work by re-assigning AF tasks
The method of activating autofocus by halfpressing the shutter release is the default setup in many cameras. But although it may be familiar, it isn’t necessarily the most effective way of working with AF. Many pro sports and wildlife photographers reassign AF activation to the AF-On button, usually located on the back of the camera. This button is designed to be accessible to your thumb and by turning on back-button focusing, you can activate AF without using the shutter release.