Nikon D6 Reference Manual page 812

File Naming
Pictures are saved using file names consisting of "DSC_"
followed by a four-digit number and a three-letter extension.
[File naming] is used to select three letters to replace the "DSC"
portion of the file name. For information on text entry, see "Text
Entry" ( 0 86).
D
File Names
•
File names take the form "DSC_nnnn.xxx". "nnnn" is a number from
0001 to 9999. "xxx" is one of the following extensions, assigned
according to the options selected for image quality and file type.
- NEF: NEF (RAW) photos
- JPG: JPEG (fine, normal, or basic) photos
- MOV: MOV movies
- MP4: MP4 movies
- NDF: Dust off reference data
•
Images created with [Adobe RGB] selected for [Color space] have file
names of the form "_DSCnnnn.xxx".
•
Both files in each pair of dual-format photographs have the same name.
In the case of dual-format photographs recorded at image-quality
settings of NEF (RAW)+JPEG, the two files will however have different
extensions (".NEF" versus ".JPG").
760 C The Photo Shooting Menu: Shooting Options
G button U C photo shooting menu