I've been walking around some landscapes and one type of photo I have a lot of trouble with is forest scenes in cloudy weather. I've tried the technique in understanding exposure but it seems impossible to get a photo that has both the trees in an adequate exposure and get the contours of the clouds in the same photo. Is there a way of doing this that I'm not aware of? Also, when I try to take portraits under such conditions the face seems to be always under exposed - the camera seems to be sampling off the trees. Any tips besides adjusting the exposure on full manual (which I do to various degrees of success)?