This is the first fisheye lens developed exclusively for use with Nikon DX Format, it is equivalent to 16mm focal length on 35mm.

The 10.5mm f/2.8G is part of Nikon's DX lens range designed for APS-C sized sensors, meaning if you put it on a full-frame FX Nikon D-SLR you'll need to crop the resolution to avoid black edges.

Ultra wide picture angle of 180 degrees on DX sensor achieved by producing a smaller image circle (the size of the image that is projected by the lens on to the sensor) enabling smaller lens diameter, lighter weight and optimal image quality from center-to edge-to-corner on the image.