This lens is optimized for 35mm film and full-frame digital, and of course works on all 1.3x and 1.6x canon cameras.
This anon ef eos 20-35mm f/3.5-4.5 works perfectly with every canon eos camera ever made, meaning every canon dslr and every canon autofocus 35mm camera made since 1987.
This means of course it works great on today's 5d mark iii and canon 7d, but it works just as well on my original canon eos 620 from 1987!
As a full-frame lens, this works on all canon slrs, regardless of format. As a full-frame lens, i will be reviewing this lens on full-frame