[davidmanze]

It can't be registration distance alone - Fuji X registration distance is even shorter than NEX and the Touit performed significantly better on the Fuji. There is probably some issue with the design of the 24 megapixel Sony sensor in combination with the short register of the E-mount. 

 

I wonder if the A6000, A5100 (both 24mp) and the A5000 (20,1mp) have the same problems with corner performance... 

Agreed, I looked at the same lens tested on the Fuji and no real problems there, although the border resolution only just creeps into very good territory. It's the Sony sensor that's the problem which is why I said the K3 does not suffer in the same way, giving the impression that the sensor's pixels are not designed for light striking at an angle, one would expect vignetting rather than softening of the image though, all in all a flaw, perhaps that is why Sony is experimenting with a curved sensor. 

  Fuji look as if they have designed their sensor with short distances in mind and have avoided this problem. I'm very impressed with Fuji's general design philosophy.