Fuji X-20 compared to Nikon D50

I'm not so sure about that.

I agree with Mr Sincere. The X-trans sensor has really shown some major advancements in how well an APS-C sensor can compete with recent model FF sensors in low light. My Xpro1 puts my X100 to shame at 6400. It's entirely possible that the X-20's new X-trans sensor could out perform the 7 or 8 year old D50 in every area except for thin DOF.

One thing for sure, the X-20 can shoot all the way up to ISO12800 at twice the resolution of the D50 that maxes out at ISO1600. So there's definitely an advantage there.

I don't know if the X-20 will surpass the D50 (up to ISO 1600), but I wouldn't be surprised if it's very close.