Fixing Chromatic Aberration 

This introduction is taken from http://www.blamethemonkey.com/chromatic-aberration
A good website with great images and good HDR tutorials..
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So your photos have been Chromatically Aberrated?Damn. That sucks….So, where the crap do Chromatic Aberrations come from?

Simple. Gnomes.

Not only do these pesky little buggers steal underpants, come to find out they live inside camera lenses and sh*! cyan and magenta. This is what’s called “color fringing” or “chromatic abberration” and occurs most often around edges with high contrast.

I know! I was just as shocked as you. Not only is it completely disgusting and unsanitary, chromatic aberration can also totally ruin your shot, especially when working with HDR Photography.

Anyway, if you don’t have any cans of industrial strength raid handy, Lightroom has the next best thing for combating the chromatic aberrations these little "gnomes" leave behind.

read the rest here: 

Fixing Chromatic Aberration