I am simply not understanding the benefit of this feature. From a YouTube tutorial I learned about AF-ON button on few cameras. In my camera (Nikon D5600), it is located under:

Autofocus Settings -> Assign AE-L/AF-L button -> AF ON

When I enabled this, the camera stopped focusing on shutter-button half-pressed. It completely now relied on the AE-L/AF-L button for me to click to set focus. In the field I tried to capture some photos. On a sudden action, I forgot to press this button and therefore camera was not able to focus. When I enabled AF-ON from the menu, my camera was in Manual Mode with AF-C and 9-Points Focus Area.

I restored the button to its default settings of AE-L and AF-L. When does it makes sense to use AF-ON ?

  • \$\begingroup\$ @Tetsujin My question is different. I am asking with the AF-C and area-modes perspective. \$\endgroup\$
    – RKh
    Jun 9, 2023 at 15:42
  • \$\begingroup\$ @RKh, the Q/A in question is exactly what you ask for. And especially for birds you set camera on continuous focus, and hold the button. And follow the bird in fly. And make a photo in right moment. \$\endgroup\$ Jun 9, 2023 at 16:07
  • \$\begingroup\$ @RKh, and to pressing/holding this button is matter of habit. Take a walk around for day and two and think all the time you need to use it for focus. And on the end you will start to use it w/o think about :) \$\endgroup\$ Jun 9, 2023 at 16:12
  • \$\begingroup\$ @RomeoNinov If I keep AF-C and hold the button pressed and follow the bird, if the bird shifts position and I point the camera again towards it. How is it different with the shutter half-pressed and bringing the subject in focus. Is AF-ON specifically for shooting from the Live View ? \$\endgroup\$
    – RKh
    Jun 9, 2023 at 17:43
  • 1
    \$\begingroup\$ Also related: What does the AE/AF lock button do that half-pressing the shutter doesn't? and What is AF-L needed for? Multiple answers to both of these questions provide a lot of detail about the advantages of using back button AF. \$\endgroup\$
    – Michael C
    Jun 10, 2023 at 14:38


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