I've played with XC 16-50 and XF 18-55, and found that the XC to be sharper than XF in the corner, even in the same aperture settings.
my XC's corner sharpness isn't that much worse than its center sharpness, in all focal range, which is quite contrary to the test result of photozone.
BTW, my XF's corner sharpness is quite consistent with review: worse in tele, better in wide.
is the reviewed XC sample a bad one?
It may well the due to the testing procedure. Lenses are tested at a distance of about 51x the focal length. This is because the testing target needs to have a specific size in the resulting image to perform accurate resolution measurements.
Sometimes that gives results that have little to do with real world usage of the lens... Maybe that is the case here too.
I have a lens which also is affected by this testing distance limitation, the Voigtländer 20mm f3.5 SL II. It will have been tested at about 1 meter distance. This lens has very pronounced astigmatism at close focus distances, but performs actually quite good at normal 20mm usage ("infinity"). So the resolution in the testing procedure looks to be worse than one achieves in real world usage.
Maybe that is the case with the XC 16-50mm you have played with, too.
Unlikely. The manufacturer MTFs do not suggest an even performance either:
http://www.fujifilm.com.au/xc16-50mm/specifications/
Another possibility is the auto-correction - the provided results present the native resolution. An auto-corrected variant will have different results depending on the camera or the various RAW converters out there.
thank you Klaus for the great reviews! love them so much!
My XC is by no means a real even performer, but much better than XF. I've shooted in RAW on X-A1 body, and processed in Lightroom.
maybe my XF is defected?
The XC was less decentered than the XF.