GTA 5 modders started making presets for ReShade SweetFX as soon as they realised the tool supports it.
To the modding community’s delightful surprise, shader-altering tool ReShade SweetFX was discovered to support GTA 5.
What this means is that anyone can download the tool, mess around with the post-processing options, and inject them into GTA 5. The tool supports presets, so anyone can share theirs online.
Which is exactly what modders are doing. This preset is made by modder K-Putt and improves the game’s shadows. Plenty more will surely go live soon.
Rockstar has not yet determined what will and won’t be considered cheating, so use this at your peril.