You asked
Best telephoto lens for the olympus om d e m1 mark ii?
For telephoto on the E-M1 Mark II, I'd start with the OM System M.Zuiko 50-200mm f/2.8 IS PRO. It's bright at 100-400mm equivalent, which matters most for wildlife and sport in poor light.
If you need more reach, the OM System M.Zuiko 150-600mm f/5-6.3 IS goes to 300-1200mm equivalent. The Olympus M.Zuiko 150-400mm f/4.5 TC1.25x IS PRO is the fast, serious option.
On a smaller budget and weight, the OM System M.Zuiko 100-400mm f/5-6.3 IS II is a sensible everyday pick. Micro Four Thirds keeps all of these smaller than full-frame equivalents, which is worth knowing when you read the wildlife and sport guide.
Written by Claude from this site's pages.