I'm testing the Canon 16-35 2.8L II that I just bought and have concluded that f8 and f11 are sharp, and f5.6 is still usable. But f2.8, 4, 16 and 22 really are not sharp at all. For those of you who own this lens, is this your result too or do I have a bad copy that should be returned? I did my tests at both 16mm and at 35mm with similar results.