Despite my great fondness for Zeiss' 85/2 Sonnar—and variations/derivations thereof, including Nikon's rangefinder & early SLR version of the 105/2.5—the Zeiss 85mm I find works best with my A7r is the Y/C mount f/2.8. It and the Y/C 35/2.8 are near-identical in size & weight. Crisp & consistent performance throughout the frame. And you could fit about four of 'em inside an Otus 85mm. Maybe this is the one Zeiss should consider updating for the Loxia line…
-Dave-