- Press the Menu button.
- Go to the yellow Setup tab (the briefcase icon).
- Select Operation Customize (Option 1).
- Scroll down and select Fn Menu Settings.
- You will see a visual grid of the 12 Fn slots (6 for the top row, 6 for the bottom). Use the control wheel to highlight the specific slot you want to replace, then press the center button.
- Scroll through the function categories to find Switch Face/Eye Subject (located under the Focus category) and select it.
How to use it now:
When you press the physical Fn button on the back of your camera, your new icon will be sitting in that slot.
Just highlight it and press the center button on your control wheel to instantly toggle through Human → Animal → Bird.
Pro Tip: To make this Fn icon even faster, remember to limit your subject choices by going to Menu → Focus → Face/Eye AF → Face/Eye Subj. Select Smrt and unchecking Human or Animal. That way, clicking it in the Fn menu instantly flips it straight to Bird!