5D3 AF Point Display
Well don't I feel like a dummy now. You are exactly right Blue, and what's more I just double checked and realized the 1D4 works the same way. It's just that when I was testing the 5D3 I hadn't been keeping my thumb on the AF-On button.
Thanks guys, mystery solved.
|Douaumont Ossuary by Eric 54-BNF|
from Armistice Day
|Silhouette at sunset by Jill Hancock|
from Portrait Lens (around 80mm or equivalent - please check the full rules)