AI Servo Tracking Sensitivity

Hypothetically if tracking sensitivity -2 meant the camera waited ½ a second before focusing on a the background if the AF point moved off the main subject, would that mean that when the AF point moved back on to the subject it would take ½ a second to refocus on the main subject again.

The camera has no idea what is the main subject and just looks at what is under the chosen AF point, the sensitivity setting determines how long it waits before it thinks you've picked something else, once it thinks that then as far as the camera is concerned that is what you are aiming at, and it will try and stay there until you move it off that target for a sufficient time for it think, eh, hang on he's moved to something else again!

it's not really that simple. It also depends on which camera model you have, since the different Servo AF algorithms used for different generations of cameras don't behave exactly the same. Three examples of models with different algorithms are the 1D Mark III, 1D Mark IV and 1DX. They all run different Servo AF algorithms.

In some cases, it's so that as soon as the camera sees something which covers the main AF point and is closer than the subject you are tracking, it will shift focus to the closer object immediately. But if you suddenly see something that's significantly further away, it will wait the delay imposed by the tracking setting before it shifts in that direction. Some cameras have a specific custom function to control this behavior separately from the tracking sensitivity.

Last time Canon gave as numbers to the delay time for the different settings was in the auxiliary advisory document about how to get the most out of a 1D-series camera, as far as I've seen.

Thats interesting, I have a 7D any idea how it's algorithm works?

Based on your example, I believe the answer is yes. I've shot several models with tracking adjustments available (7d, 1D3, 1D4, 5D3) and the "delay" once it slipped off the main point was the same as going back to main point. Certainly there are ways to work around it a little quicker, but I've never noticed a difference. The 5D3 can do some different things though within it's AF module, so it's the outlier.

match14 wrote in post #16815528
Thats interesting, I have a 7D any idea how it's algorithm works?

As it shares the same AI Servo II algorithms as the 1D IV, it should be close to its methodology, with maybe some in-camera settings tweaked to detune it, or disable things due to fewer AF points.

The 7D is a AI Servo II AF algorithm camera. In the default configuration, it should refocus on a target at closer range immediately, regardless of the tracking sensitivity setting. But if C.Fn III-3-1 is set and you are using more than one AF point and there's something for the auxiliary points to track, something that's not covered by the obstruction.

Thanks for all the replies I've got a much better understanding of how AI Servo works now.