Warren is absolutely right, with a 6D ii you need an EF lens, not the EF-S. And EF lens will fit on a crop sensor Canon, but you won’t get the most out of it. But the other way round doesn’t work – so for your full frame 6D ii definitely stick to EF. If you’re not sure and the forum takes a while to reply ask Canon on their Live Chat ( https://bit.ly/2Y6IbTY ) – their response time for my questions has always been immediate. Some of the L series (red ring) lenses are absolutely incredible too. Good luck with the photography George! 🙂