When searching for FG/GI ressources, I found that step by step guide. It's about importing a solidworks model in fact, but scroll down a bit, and there's a comprehensive guide for HDRI.

Well, seems many problems arise through oversaturation.
And i've read about some explanations telling this was due to a Pi division, not implemented, which causes this overvalues in lighting.

Dunno if it's true, btw, 't seems being a good starting tip for HDRI gamma correct (file gamma correct).


Hope this will help


(maybe to mention I didn't need gamma correct though under v7)