Canon EOS-1D X Mark III DSLR Camera (Body Only) - Manual (Page 279)

High Frame Rate
You can record Full HD movies at a high frame rate of 119.9 fps or 100.0 fps. This is ideal
for recording movies that will be played back in slow motion. The maximum recording time
per movie is 7 min. 29 sec.
Movies are recorded in or quality.
Sound is not recorded in High Frame Rate movies.
Time code display during movie recording advances 4 sec. per second.
Because High Frame Rate movies are recorded as 29.97 fps/25.00 fps movie files, they
are played in slow motion at 1/4 speed.
Caution
Precautions when set to [High Frame Rate: Enable]
Time codes are not recorded when [ Count up ] is set to [ Free run ] in [ : Time
code ] ( ).
Check the [ Movie rec. size ] setting if you return this setting to [ Disable ].
The screen may flicker if you record High Frame Rate movies under fluorescent or
LED lighting.
For a moment when you start or stop recording High Frame Rate movies, the
movie is not updated, and the frame stops momentarily. Be aware of this when
recording movies to external devices via HDMI.
Movie frame rates shown on the screen as you record High Frame Rate movies do
not correspond to the frame rate of the movie recorded.
Headphones cannot be used (no sound is audible).
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