20D AI focus and burst mode / panning shots

I have a hard time using AI focus while in burst mode. The manual says if you press the shutter halfway it'll focus on the closes AF point and adjust accordingly to the moving subject.

Let's say I'm doing a panning shot, would I have to shot in one shot modes for the AI focus to take effect?

Use centre AF point and set you custom parameter to use the "*" button for focus, also use AI servo that separates focus from Exposure and track the object with the "*" button then shutter button to take the shots when ready.


RoB B

would that be the same as setting to ONE SHOT AF mode and fire away?

At times, I'm not sure if I can track a moving subject that fast. How does AI Focus work in burst mode?

No. One Shot mode doesn't track a moving subject, Servo does. In One Shot, once the camera locks focus you have to release the shutter button or the * button and reapply it to focus again. In AI Servo, the camera uses predictive focus to track a moving subject.
Using CFn. 4-1 and AI Servo gives you the benefit of both. Tap the * button to lock focus on a stationary subject and release, recompose gives you One Shot.

I'm not sure many people use AI Focus here. From what i read on it in the manual, it switches to AI servo once it senses the object is moving. I'm not sure how quickly it does this. For the most part i stick with One Shot, or AI Servo for sports, or moving objects.

Just at least track the object in your viewfinder. IN AI servo, it will focus on the object even when it moves to another focus point.

In using AI Servo with a moving subject, many people find that continuous shooting gives you more in focus shots. The first shot of AI Servo(Single Shot or Continuous) is always "Release Priority"- the camera shoots when you fully depress the shutter whether the subject is in focus or not. In subsequent shots in Continuous Shooting-AI Servo, the camera switches to "Focus Priority"-it won't fire unles you are in focus.

Mr. Berger is correct again - and thats the way I shoot horse events.

I did some test shots yesterday around a mildly busy road. If I remember correctly, this was my setting: 1/60 @ f8 ISO100. AI Servo - burst mode, hand held. Coincidence or not, but I notice better shots for subjects furthest away from the camera. Lens is the standard 18-55mm.

The further away from the camera the deeper the DOF.

Also, the further away the subject, the less the rate of change of subject position, consequently the less the lens needs to re-focus and the more even the focus change will be.