Canon EOS-1D X Mark III Advanced User's Manual page 293

Drop Frame
The time code's frame count will cause a discrepancy between the actual time and the time
code if the frame rate is set to
discrepancy is corrected automatically when [Enable] is set. This correction function is
called "drop frame."
Enable
Corrects the discrepancy automatically by skipping time code numbers (DF: drop
frame).
Disable
The discrepancy is not corrected (NDF: non-drop frame).
Time codes are displayed as follows.
• Enable (DF)
00:00:00. (Playback: 00:00:00.00)
• Disable (NDF)
00:00:00: (Playback: 00:00:00:00)
Note
Drop frame is not used for
(24.00 fps), or
not displayed when
is set to [For PAL].)
(119.9 fps),
(100.0 fps),
(23.98 fps) frame rates. (The [Drop frame] setting item is
/ / / /
293
(59.94 fps), or
(50.00 fps),
is set, or when [ : Video system]
(29.97 fps). The
(25.00 fps),