Nikon D780 DSLR Camera (Body Only) - Manual (Page 696)

650 Menu Guide > A Custom Settings
Choose the focus speed for movie
recording when using lenses compatible
with this option.
Use [ When to apply ] to choose when the selected option
applies.
g3: AF Speed
G button
U A Custom Settings menu
Option Description
D [ Always ]
The selected option applies whenever the live
view selector is rotated to
1 .
E
[ Only while
recording ]
The selected option applies only when recording
is in progress. At other times, the focus speed is
“+5”, or in other words as fast possible.