The first fisheye lens specifically made for a digital SLR, this DX lens packs stunning performance into a cute, small, and neat package. The image circle is optimised for the DX chip of the D1/D2-series cameras and the D100, and encompasses a true 180° view. The Nikon Capture 4.x or other software can transform this into a huge 120° rectilinear view, with a sacrifice in sharpness into the extreme corners of the image.
A sophisticated optical design with ED glass ensures high colour saturation and image sharpness, and field testing confirmed that Nikon has another winner on their already extensive list of lens offerings. Images are vividly colour saturated, chromatic aberration may be absent for distant scenes although some is present for close-ups, no corner fall-off and virtually no flare (of course, since all light rays entering the lens are image-forming). Ghosting is very well controlled, too. The near focus limit at 0.14m makes for some pretty strange pictures as well.
I recently downrated the 10.5 mm lens on DX format because further experience shows it is more troubled with CA than I initially observed. There seems to be some between-sample variation with respect to CA, too. Still, given judicious post-processing, you can achieve very sharp and colour-saturated images with this small fisheye lens. Nikon Capture promises to "defish" NEFs taken with the 10.5 mm, but the final result often is disappointing. Much better results can be had using Panorama Tools (ReMap module).
With the FX-format (D3) camera, CA issues seem to be kept under better control. I modified my 10.5 in anticipation of the D3's arrival, so by sawing off the built-in lens hood, it now gives a picture angle > 200 degrees. The image circle projects outside the frame, though. No big deal if you plan on making stitched panoramas or suchlike projects.