Well I guess that's the exact point of it all. There's a lot of differences between lenses just as people's taste for these differences are well different! So there's a need to understand that not only the new ones push the edges of technology but the old ones help in even better stealth and so on, at least by design. There's plenty of different ways to compare. But one thing is for sure. No two lenses are ever the same. And they all are created on their own basis of whatever they want to push that specific lens for.