definitely the tokina if you can afford it. There are people who are rehousing these lenses and adapting them (permanently) to PL mount. They pay over $3000 for this. It is seriously one of the best wide angles you can get. I think some people also use it on full frame zoomed in to 16mm, because it is that good. I am not speaking from experience, but nearly anyone on this site can tell you that it is simply an awesome lens