Canon EOS-1D X Mark III DSLR Camera (Body Only) - Manual (Page 364)

Case 4: For Subjects That Accelerate or Decelerate
Quickly
Default
• Tracking sensitivity : Responsive : 0
• Accel./decel. tracking : +1
Setting to keep tracking and focusing on subjects even if they suddenly change speed.
Effective for subjects having sudden movements, sudden acceleration/deceleration, or
sudden stops.
Note
Try setting [ Accel./decel. tracking ] to [ +2 ] to keep up with subjects that change
speed significantly from moment to moment ( ).
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