Originally posted by calicojack 
Of course I realise that bthe center focus point must be larger than the little red dot. Do you have any idea how much larger?
I've seen pictures posted; you might try browsing around for some. I seem to recall it being about a third the height of the frame, but fairly narrow.
Quote: Also, I would have thought that the difference between the bright colored can and the muted shades of the leaves would give the greatest contrast.
I don't think the AF system is as sensitive to difference in hue or saturation are it is to difference in value (light and dark).
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