About the Parameters
Tracking Sensitivity
 | Sets the subject-tracking sensitivity during AI Servo AF when an obstacle enters the AF points or when the AF points stray from the subject |
[0]
Standard setting suited for most moving subjects.
[Locked on: -2 / Locked on: -1]
The camera will try to continue focusing the subject even if an obstacle enters the AF points or if the subject strays from the AF points. The -2 setting makes the camera track the target subject longer than with the -1 setting.
However, if the camera focuses the wrong subject, it may take slightly longer to switch and focus the target subject.
[Responsive: +2 / Responsive:+1]
Once an AF point tracks a subject, the camera can focus consecutive subjects at different distances. Also effective when you want to always focus on the closest subject. The +2 setting makes it quicker to focus the next consecutive subject than with +1.
However, the camera will be more prone to focus on the wrong subject
[Tracking sensitivity] is the feature named [AI Servo tracking sensitivity] in the EOS-1D Mark III/IV, EOS-1Ds Mark III, and EOS 7D.
Accel./decel. tracking
 | This sets the tracking sensitivity for moving subjects whose speed can suddenly change dramatically by starting or stopping suddenly, etc. |
[0]
Suited for subjects that move at a fixed speed.
[+2 / +1]
Effective for subjects having sudden movements, sudden acceleration/deceleration, or sudden stops. Even if the moving subject’s speed suddenly changes dramatically, the camera continues to focus the target subject. For example, for an approaching subject, the camera becomes less prone to focus behind it, which would result in a blurred subject. For a subject stopping suddenly, the camera becomes less prone to focus in front of it. Setting +2 can track dramatic changes in the moving subject’s speed better than with +1.
However, since the camera will be sensitive to even slight movements of the subject, the focusing may be unstable momentarily.
AF pt auto switching
 | This sets the switching sensitivity of the AF points as they track the subject moving dramatically up, down, left, or right. This setting takes effect in the following AF area selection modes: AF point expansion (Manual selection  ), AF point expansion (Manual selection, surrounding points), Zone AF (Manual selection), 61-point automatic selection AF. |
[0]
Standard setting for gradual AF point switching.
[+2 / +1]
Even if the target subject moves dramatically up, down, left, or right and moves away from the AF point, the AF point switches to another one to continue focusing the subject. The camera switches to the AF point deemed most likely to focus the subject based on the subject’s continual movement, contrast, etc. Setting +2 makes the camera more prone to switch the AF point than with +1.
However, with a wide-angle lens having a wide depth of field or if the subject is too small in the frame, the camera may focus with the wrong AF point.
