Nikon 16mm f2.8D

If you shoot full frame this is the working lens for you. On a DX camera it is not at its best potential, but still sharp as a tack. This is my primary wide angle working lens

Simply the 'dogs' as we say in Britain. This is the best lens by far for wide angle on the FX format. Super sharp at f8. It maybe just a touch soft at f2.8 at the edges but for wreck photography for instance perfectly acceptable. You need to make a neoprene jacket to go over the top to prevent internal reflection - especially if you like big dome ports.

Beautiful lens that's hard to fault. Becomes the wide standard of choice for most applications.