Having bought a D850 I have no full frame lenses wider than 70mm ( I have Nikkor 70-200, 200-500 and 100mm macro FX lenses) as the ones for my D500 are DX lenses. So I need an FX lens for landscapes. What do people recommend? Can be Nikon or Sigma, Tamron etc. Happy to buy secondhand. Budget up to £1k