Well, because of you all, I installed FStorm to see what the fuss was about. One of the first things I noticed was that Dubcat's Fstorm LUTs are very strong imitations of the default tonemapping in Fstorm.
My first impression is that FStorm is like driving a rally car or a Koenigsegg, while Corona is like a Porsche or Ferrari. There is a difference in the manner of safety nets in place to guide the experience and at the end of the day they are just different things - reminds me a lot of Unity vs. Unreal.
I spent the last couple nights comparing basic scenes - thinking I'd scale up to something more complex - but the more I tried to control for different variables in the renderers, the more futile it felt to do so. The two renderers just aren't the same: shader, render settings, tonemapping, enviro mapping, gamma controls, etc. I had some naive sense that updating a scene to run in Fstorm from Corona would be a little more than trivial, but that was not my experience.
Nevertheless I did some basic tests in which I attempted to control for as many extraneous variables as possible (given my limited understanding of Fstorm) and was surprised by the results.
- Corona renders use Dubcat's Fstorm 0.30 contrast LUT at 0.90 opacity, EV = -.75, sharpening (3.0, 0.05, 0.25), other settings at default, no bloom
- Fstorm renders use default settings
- Grey is 186,186,186; 0 glossiness
- One light source; interior HDRI from Dubcat.