BACK-BUTTON AF

With back-button focusing, you assign a ‘back’ button to focus and no longer ‘half-press’ the shutter to focus. This separates the relationship between focusing and taking an image. Shooting and focusing with the shutter button means that every time you press the shutter, you will lose focus for a short time until you ‘halfpress’ the shutter again. Even though Nikon cameras acquire focus quickly, you will still miss a few images. The AF-ON button is used for back button focusing (if you don’t have an AF-ON button, assign the AE-L/AF-L button to operate as AF-ON). Focus using the AF-ON button and press the shutter button to take the image. Back-button focusing can be used with either AF-S or AF-C modes. Using AF-ON gives you an advantage when tracking moving subjects. If you keep the AF-ON button pressed down in AF-C mode, you are now constantly focusing on the subject under the active focus point(s), even when you press the shutter button to shoot a sequence of photographs.