Nikon D750 User Manual page 468

A
Flash Control Mode
The information display shows the flash control mode for optional
flash units attached to the camera accessory shoe as follows:
i-TTL
Auto aperture (AA)
Non-TTL auto flash (A)
Distance-priority
manual (GN)
Manual
Repeating flash
Advanced wireless
lighting
D
Use Only Nikon Flash Accessories
Use only Nikon flash units. Negative voltages or voltages over 250 V
applied to the accessory shoe could not only prevent normal
operation, but damage the sync circuitry of the camera or flash. Before
using a Nikon flash unit not listed in this section, contact a Nikon-
authorized service representative for more information.
440
Flash sync Auto FP (0 345)
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