At night this setting makes a huge difference, and probably will have little, if any, effect on your FPS.
Trust me. Move it off the Medium setting up to the Very High, or even the Extremely High setting.
This picture won't show what you get, not very well, but just try it.

You may find yourself flying more often at night.
BTW - HDR Brightness in on 1.12, Bloom on 1.00, Saturation on .80