I am currently using a DX Nikon with my Nexus 160mm glass dome, 15mm extension and 10 - 17 Tokina. And am happy with the corner sharpness.
When I get my D700, am I correct in thinking the full frame will use more of the edge of the dome and so I should be concerned about corner sharpness again.
Thanks
Mary
There is no lens in full frame that will give you a coverage wider than the 10-17 (180 degrees). If you use the 16 fisheye, it will be like using the tokina on 10mm, so corner sharpness should be similar.