Nikon D780 DSLR Camera (Body Only) - Manual (Page 666)

620 Menu Guide > A Custom Settings
Choose the slowest shutter speed available with a flash in mode
P or A .
Regardless of the setting chosen for e2 [ Flash shutter speed ],
shutter speeds can be as slow as 30 s in modes S and M or at
flash settings of slow sync, slow rear-curtain sync, or red-eye
reduction with slow sync.
Choose how the camera adjusts flash level when exposure
compensation is used.
e2: Flash Shutter Speed
G button
U A Custom Settings menu
e3: Exposure Comp. for Flash
G button
U A Custom Settings menu
Option Description
Y E
[ Entire
frame ]
The camera adjusts both the flash level and
exposure. This changes the exposure for the
entire frame.
E
[ Background
only ]
Exposure compensation is adjusted for the
background only.