I have a sigma 4.5mm for a week with my D40 and then I'll try out a sigma 8mm the following week. I'm trying to figure out the best way to mount my camera to the NN5. Should I use the upper or lower rail? Portrait or Landscape mode? I can't seem to find any info in the database with this lens.
You should mount the camera on the upper rail. Tilt the upper rail up by 5 deg, take 3 shots around.
Try to do the calibration yourself. It takes just a few minutes.