Experimenting with settings today, I found one that makes a pretty dramatic difference to my view... the Depth of Field. On my system it makes everything noticably fuzzier. Besides the overall slightly less-focused appearance, look particularly at the red clay bank on the left and the sharpness of the distant mountain crest where it meets the sky (screenshot processing for posting makes the difference less drastic than the real in-game view):
Depth of Field disabled:
Depth of Field enabled: