You say you were in "auto" mode, but the EXIF report your were actually in Aperture priority (Av) mode. That's sort of automatic, but it does require you to set the aperture yourself. If you choose a very small aperture like f/22, it should be no surprise you get a slow shutter.
But FWIW, the images posted do not overexposed to me, nor do they look unusually unsharp.
Quote: Also I do not understand the purpose of 1/2 and 1/3 EV steps.
This setting controls whether each click of the dial changes shutter speed or aperture 1/2 stop of 1/3 stop. if you don't have a reason to need to set shutter speed in 1/3 stop increments, just leave it at 1/2.