I finally got a chance to try my 10-20 on my 1d, and i must say its quite exquisite. without hood, it doesnt really vignette unles its at 10mm. it works really well at 11mm up until f9-f18 where you see slight vignette, but very very little, i would say 2% into the corners. Perfectly usable. I thought i was going to sell this lens and getteh 12-24 mainly sue to its FF compatibility, but this works great...
Here are the pics.
11mm at f4.5
11mm at 6.3
11 at f9
all of which can easily be eliminated in post.
11mm @ f9 PP'd out the Vignette, really easily too, LENS correction 100% and done. (still a little there but def not a problem)
ib.cleanyourdesk.jpg
Here are the pics.
11mm at f4.5

11mm at 6.3

11 at f9

all of which can easily be eliminated in post.
11mm @ f9 PP'd out the Vignette, really easily too, LENS correction 100% and done. (still a little there but def not a problem)

ib.cleanyourdesk.jpg