Rokinon 8mm F3.5 Fisheye (samyang) sharpness and focusing question

Samyang seems to have a problem with the calibration of the focus ring -- see the following links:

http://forums.dpreview.com/forums/thread/3102330

http://www.4photos.de/camera-diy/Samyang-Walimex-Rokinon-Vivitar-Falcon-14mm-2.8-Focus-Correction.html

(The last is for the 14mm, but it also explains how to correct it yourself).

I have the lens, and it doesn't seem to have that problem (very hard to test with a fisheye, I tried with close focus, and even then the test-chart was very small...).

Still, 3.5 is not really usable (but it gets better at the next "clickable" stop), and the lens is less sharp close up then at infinity.

So not that good for those skateboard shots or funny portraits, but (at least for me) perfectly fine for landscape and everything else at f8 and infinity.