While the 5D shoots a rapid set, will the focus change during the burst?

[jonathan7007]

Scenario:
Set on "One Shot" you focus and recompose (perhaps the focus sensor isn't close enough to the edge of the frame...) and squeeze off a short burst on motor drive setting.

Will the camera re-focus on the new "target" of the chosen focus sensor after the first capture?

What if the focus setting is AI Focus or Servo? I think here it WILL refocus.

I called Canon this evening to ask, and the gentleman in Chesapeake, VA, said, "Hmmmmm...." and that he will get back to me.

...sometimes I shoot manual focus again. I get frustrated by constant moves back to the focus point, make another half-press... well, you get it: if the light, subject, and available depth-of-field allow manual focus -- and will not change -- I am starting to go back to the "old" way. Canon suggested I try using the AF-Focus button and that's interesting work-around, but I would try to assign the "M-Fn" button to that task, because it's near the shutter and it uses the index finger. Faster reaction than jamming my thumb up by my cheekbone to find that AF-Focus button among the three that are there.

jonathan7007

[Mt Spokane Photography]

5D, 5D MK II, or 5D MK III?  Different answers for different bodies.
However, in one shot mode, the focus does not refocus if you hold the shutter button down.  Use AI Servo.  The 5D MK III has settings to determine shutter priority or AF priority.

[neuroanatomist]

Canon suggested I try using the AF-Focus button and that's interesting work-around, but I would try to assign the "M-Fn" button to that task, because it's near the shutter and it uses the index finger. Faster reaction than jamming my thumb up by my cheekbone to find that AF-Focus button among the three that are there.

Depending on the body, the AF-ON button is a slightly different size or separated more from the other two.  Since you mention M.Fn button I assume you've got a 5DIII.  AF + Metering start cannot be mapped to the M.Fn button, only to the AF-ON or AE Lock buttons (or the shutter half press, of course), or to the AF Stop button if you're using a supertele lens.

But back-button AF is probably the best solution if you want to focus-recompose.  Once you start using it, it becomes automatic, and the only time it's an issue is when you hand your camera to someone else (but the 5DIII has the green square mode, which will cancel out back-button AF).