What does Gradient Correction do?
I'm pretty sure its intended function is to give better camera angles when Rex is in small areas and climbing up hills and mountains for example. The automatic camera can end up close to the ground, which isn't the greatest when you need it high up behind Rex for climbing. Gradient Correction should keep the camera higher up, though the difference can be negligible occasionally. I usually keep it on, but I find myself adjusting the camera anyway.