Originally posted by Marc Sabatella That's no backfocusing. Backfocusing is the camera missing focus by a few millimeters on the target it chose. The discrepancy here is one of many meters. That's simply a case of the camera *choosing* to focus somewhere other than where you intended. It either saw right through the fence to the background and choose to focus there (a legitimate choice), or it is not using the center point even thoug you selected it (if so, a camera problem).
If that's back focusing, it's back focusing to infinity. Frankly, I think he's conducting the test very poorly.
Ubuntu, please use a simple flat surface, not a chain link fence with holes in it. Try a wooden one or a wall with decorative wallpaper. Even better, print out a focus distance chart and use that. Focus on closer distances, like 2-3 feet away, not 15 feet away.