Manual AF Point or Automatic AF Point?

[SteveHall]

I posted these questions on the Canon Camera topic forum but got no response, so I thought maybe I should try this forum since the questions may be more applicable to wedding photography.

On page 67 of the 20D owner's manual, under the topic "Selecting the AF Point" it discusses the selection of Manual AF Point selection and Automatic AF Point selection. I have always "defaulted" to manually selecting a single AF point, however I wonder if any of you have used the Automatic AF Point selection function, allowing the camera to select the focus point? If so, in what situtations have you found it useful and has it produced accurate focus for you?

I also have a couple of questions in regard to the AI Focus function. Do any of the wedding shooters use AI Focus while shooting, say, the aisle shots or dance shots? Are there any other instances while shooting a wedding that you find AI Focus particularly useful? Do you use the AI Focus or just go ahead and set it the camera on AI Servo?


Thanks!

[KirkDarling]

I activate all points when using AI Servo to track a moving subject. If the subject is not moving, I use One Shot.

Like nearly everyone, I have not gotten over the quirks of using AI Focus. I do, however, understand its intent. You see, One Shot is the fastests focusing mode; however in One Shot, the shutter is locked until the camera is satisfied with the focus. AI Servo is a bit slower, but it doesn't lock the shutter--you can snap at any time and take your chances with whether the camera found the correct focus. The intent of AI Focus was to gain the One Shot speed, but unlocking the shutter (and then tracking) if the subject appears to move.

It ought to work that way, except many people prefer to "focus and recompose," which means using the central AF point to focus, the shifting the camera for best framing. But AI Focus usually interprets the camera movement as subject movement, so it breaks the original focus and refocuses---where you didn't want it.