I have a problem with the edge effect that shows a magenta fringe on the edges or dark against white areas. This is really a problem when taking photos of trees against a light color sky. The tree's branches will have a magenta cast. Looks terrible. I don't think that this is a chromatic aberration problem. That has more to do with off axis locations when using wide-angle lenses. From what I've heard, it's a problem when a dark area is juxtapositioned directly next to a light area. e.g. trees against an overcast sky. It can occur with any lens, not just wide-angles. What's the best way of getting rid of this? Is there software designed to attack this problem? I know that this is a common problem.