Nikon Df - Manual (Page 292)

272
U
Memory cards must be formatted before first use or after being
formatted in other devices. Format the card as described below.
1
Highlight Yes.
To exit without formatting the
memory card, highlight No and
press J.
2
Press J.
Press J to begin formatting. Do not
remove the memory card or remove or
disconnect the power source until
formatting is complete.
Format Memory Card
G
button ➜ B setup menu
D
Formatting Memory Cards
Formatting memory cards permanently deletes any data they may contain.
Be sure to copy any photographs and other data you wish to keep to a
computer before proceeding (0 211).