Currently there are 35 native Wideangle Prime lenses for Panasonic S1R and 27 of these lenses are autofocus (AF) type.
S1R also has a sensor based image stabilization system which means that all of these lenses will be stabilized when used on S1R.
Since Panasonic S1R has environmental sealings (Weather Sealing), you may like to couple your camera with one of these 20 Wideangle Prime lenses with Weather Sealings.