I think something is missing here. L lenses are all EF mounts, which fit crop sensor models. Even EF-S lenses are still "cropped". Lenses are all listed by their full frame lengths, even EF-S ones. So the canon 55 -250 EF-S is multiplied by 1.6 times being 88 - 400. It is not just Canon that does this, they all do, except Nikon and Sony use 1.5 times.
Then again I may be missing what it is you are talking about
