At Photokina 2018 PGN interviewed Managing Director of Fujifilm UK – Theo Georgiades – about the Fujifilm GFX 50R and GFX 100S. And at the end of the interview, Theo Georgiades confirms that the 26MP sensor inside Fujifilm X-T3 is made by Sony, not by Samsung:
Definitely not a Samsung sensor. It’s the same manufacturing process that we have gone through with all our other X-Trans sensors. Still designed and tested all by our R&D team.
The new Fujifilm X-T3 mirrorless camera is now in stock and shipping in the US: