Amaremdra, The problem is that the sky is a LOT brighter than the subject it is illuminating. There are only two ways to bring out the blue in the sky: Polarizing filter. Works differently depending on the angle you are to the sun. Graduated Neutral Density filter (gray at one end, clear at the other), generally a 0.6 or 0.9 version (two or three stop difference). Lee and Cokin are leading brands. Hope this helps. Colin
