Why doesn’t Nikon make lenses that are as wide as it used to?

Chris says… One reason is that manufacturers have to make two ranges of wides: one for DX SLRs, and one for FX models. Nikon once made a 6mm fisheye, but its current widest DX models are the 10-24mm or the 10.5mm fisheye, and the widest FX lens is the 14mm, or 16mm fisheye. Sigma stretches further, producing a 4.5mm circular DX fisheye, and an 8mm FX lens.