Early this year, I acquired a used 20mm ƒ/1.8G Nikkor lens. I only have DX bodies and the 20mm works more like a wide-normal prime than an ultra-wide, as on FX.
Why use 20mm ƒ/1.8G? on DX?
I had long wanted to have a small, fast 24mm prime for my DX bodies. While the 35mm ƒ/1.8 DX is compact enough, I don’t like it that much. The FoV (51mm FX equivalent) is too narrow for general photography and too wide for portraits. I do most of my portrait work with a 50mm ƒ/1.8G, so I need something to cover the wider end.
The 20mm is not a bad option. Its 30mm FX equivalent FoV actually matches that of some very popular smartphones, which is what I intended this lens for – having a smartphone camera equivalent with much superior image quality.