It appears the rear cameras are comparable? 12 mp f/1.8 and f/2.8 on the telephoto. Then apple says its lets in more light faster and bigger. but only with those words. Not sure what that means? Then there is slow sync and portrait lighting. So is there a compelling reason for most people to upgrade for rear camera? from 7plus to 8plus? Specifically talking about back camera and photos. I know video at 4k/60 is a good upgrade.