Title says it. Altian environment becomes generally either too bright on a daytime, or a bit dim in a full moon nighttime.
I played with setaperture a bit - setting correct values seemed to resolve the problem. There are also sort-of aperture variables in cfgworlds, which do things related to aperture adjustment, yet too mystical for me to find\guess better values and mod them in, besides i'd also have to relate arma's aperture values (measures) to real world limitations of the human eye; it is possible to turn eyes into an NVG by doing it wrong.

Setting HDR to low is pretty vital for me, not only it wins frames, but also makes gun movement very responsive.