Originally posted by troywhite Absolute and utter crap.
I've stood beside both cameras during group shooting sessions and heard *both* models you quote hunt around like psychos for focus as much as mine did.
I've actually used all three cameras and I can tell you that the 400D and the 40D are quicker at focusing. My sister owns both of them and I have the K20D. When using the Tamron 28-75mm lens on the 40D and the K20D and attempting to lock focus on something inside, the 40D won hands down, every time. Half the time the K20D didn't even lock focus, just kept hunting. My wife and my sister and husband have all played with all the camera's and they all say the same thing, that the K20D is a lot slower to focus indoors. Outdoors there isn't as much in it, but it's still slower. The 40D especially has a very swift solid focusing feel to it. It just locks into position very fast.
Have you used a 40D before? If not, try it before telling my I'm spouting crap.