Bracket, Bracket, Bracket and Bracket some more!!!!! The particular setting I use with my DX6490 and the one you use with your DX7590 are the same but when you use the same ones I use down here in Alabama, just consider them guidelines, nothing more. There are just too many variables involved. Cloudy sky, hazey sky, sunny sky but a different time of day or a different place on the globe, which changes the elevation of the sun even if we are on the same continent. Different filters or one of us ( think Dawg here ) might not clean our lens the same. Different post processing, different camera settings that are not posted, saturation,sharpness, mega pixel choice, How shaky I happen to be. More Icehouse the steadier I get. Like I said a lot of variables. To help with this Bracket the shot by changing the f-stop up and down, the shutter speed up and down and the iso and exposure compensation up and down. Try to pin down from your source the exact kind of filter used if any and all the data you can, then Bracket , Bracket, Bracket and Bracket some more. I't will be a revealing experience for you.