i've got three primes in mind for portraits; 85/1.4, 105/2 dc, 180/2.8. unfortunately, here in ottawa, these are very rare lenses to buy. actually, i don't know anyone that owns one, either. i just wanted to know which is going to be sharpest. 105, i think would be the perfect focal length, but i doubt the sharpest. i'm leaning towards the 180/2.8 but it seems a little long, especially with a 1.5x crop - 270ish mm. anyway.. sharper lens of the three, anyone? examples would be awesome, if possible. thanks in advance.