I've noticed that many of the wide angle prime lenses (at least for Canon) have somewhat smaller apertures than their normal or telephoto counterparts. E.g. the regular Canon 24mm prime is f/2.8 while ...
I am looking for a wide angle lens for my D90, between 12 and 18mm focal length, preferably a prime, because I like fast(er) and cheap(er) lenses. Any recomendation ? Thanks