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."