HDRIfy

HDRIfy is a shader node group that will change a low dynamic range image into a reasonably good fake HDR image. HDRIfy node scales image values from 0-1 to your desired maximum value and gives you quick and simple sliders for rudimentary curve adjustment (shadows, midtones and highlights).

HDRIfy also comes with a fake sun that can boost highlights in reflections or cast a shadow.

Shadow softness depends on fake sun size and exponent.