General What are the advantages that primes have over a zoom lens?

[randomname]

I definitely don't aggree

with my t2i recording 1080p video, I can see the difference between a sharp lens and a very sharp lens, and the difference between a sharp lens and a soft one is absolutely huge
http://www.dvxuser.com/V6/showthrea...s-matter-for-video&highlight=sharpness+matter
http://www.similaar.com/foto/lenstests/lenstestsv.html

as for the tamron 17-50 VC or non-VC:
I have only used the non-VC variant (and it's great), but I've seen some tests on the web and the VC is seemed horribly soft

Nobody was arguing that there isnt a difference in sharpness between f stops, if you did that test again between different lenses I'd be willing to bet anything that there will be 0 perceivable difference.