How Canon AI-Servo mode works

[DavidEccleston]

I found this document online, referring to older Canon EOS-1 cameras, about how the EOS AI-Servo predictive auto-focus works.


It is fully expected that the first frame of any moving subject is OOF, regardless of how long you track the subject with the shutter half-pressed. Prediction only kicks in, incontinuousmode, after the first shot has been taken, which isn't exactly what I expected... I expected that if I track for a second or two, it should be fine in 1 shot mode. Nope.


The document also confirms that it does track acceleration as well as velocity, which was something I wondered about.


It would be nice if Canon had dedicated a sentence or two of their manual to how the predictive focus functions are supposed to work. It doesn't matter how advanced their focus system is if the majority of their customers don't know how to take advantage of it.


Link to document

[nickds7]

I dont trust it . Can't risk missing a shot relying on ai.

[Keith B]

I've always had good results. I always pan with subject find it's path, when it gets close to point I want, I press the shutter half way, pause ever so slightly (even though there is no beep) then press completely. I rarely have missed shots. Sometimes the first shot isn't the sharpest but I usually am not shooting with the intension of the first shot being the winner.


These were shot in a sequence using Servo. I shot about 7 frames for this sequence. Two before the first image, one after, then the second image and two after. All the shots were in focus these were just the optimum points of the maneuver. Servo work best because as the wave peels it also moving closer to the camera.

[tancanon58]

Have anyone tried to use AI Servo on 5D2? What are the results?