Comments from DXO Mark:
"In third place overall for all 85mm primes we’ve tested on the
EOS 5DS R, the
Tamron 85mm f/1.8 sits just behind the $4490 Carl Zeiss Otus 85mm f/1.4 ...... The Tamron lens also
ranks ahead of both the Mark I and Mark II versions of Canon’s own $1899 85mm f/1.2L II, which sit in fourth and fifth place, respectively."