With regards those three images, the first is, if you honour iso in EV calculations (which is debatable but consistent) EV+3, this is well within the AF speces, in the order of 32 times more light than minimum, it also has a very strong bar of contrast through it, this image is no test of AF.
The second image is, obviously, underexposed, but is exposed at around EV+0.5, again, well within Canon's stated AF specs.
The third image is impressive, if it is 1.3 seconds as the EXIF indicates that makes that an exposure in the order of EV-3 that is half the light that the specs list, EV-2. It looks like an accurate representation of the scene, though again, there is some good contrast areas of the subject. But it is impressive.