just snapped up a Canon 135mm f 2.8 lens off ebay for $26
just happened to find it with only 2 min left.

that gives me a 135mm 2,5, 28mm 2.8 and a 50mm 1.8
what should i be looking for next...
(i want to grab up a 1.4 50mm sometime soon)

and yes.. i agree with whoever said it first: lenses are like crack

I got an FL 1.2 which is GREAT - sooo little focus though hehe...

need to get a better GG/"commercial" adapter... my home made job shows grain if my lens is stopped to anything aside from 1.2...

Would love a 28 1.8 (1.4 would be wishing...) - currently have a non canon 28mm 2.3 I believe and u can see grain because it doesn't let enough light in...

making this homemade adapter has confirmed that it is worth the purchase though...

back to your Q.... I recently saw a nikon digi with a 12mm sigma... OMG the image was gorgeous and with very little distortion.... don't know if u can get a 12mm that will let enough light in...but damn if u could hehe...