I have a 30D and 10-22mm and I've just recently upgraded to the 5D Mk2. I will now use my old 30D as a backup camera. My main question is should I continue using the 10-22mm on my 30D or should I sell the lens and get the 16-35mm for my new 5D instead? Is it worth the upgrade? My main thing is will I see a big difference in picture quality?

