HIGH ISO Sony A7II Vs. Fuji X-Pro2: “Even at ISO 25,600 difference less than half stop. X-Pro2 better color fidelity. Well done, Fuji!” – Fuji Rumors

At ISO 6400 and below, the two cameras are extremely close in noise performance…I’d estimate 1/3 stop difference or less.  At ISO 12,800 and 25,600, the difference is a bit more pronounced, but still less than a half a stop difference, which I think shows a great performance from the X-Pro2.