In this video i hope to explain to you what Chromatic Aberration (1 b 2 r) is. It is the random colour fringes that you get at areas of high contrast. The better the lens you own the les cromatic aberation you have. The photos were taken with the nikon 50mm f1.4 at different apertures. wide apertures usually result in more chromatic aberation than small (higher f number). However using adobe lightroom it is much easier to get rid of the colours.
on an other note that if you shoot in jpeg the nikon d300 automatically takes out a lot of the chromatic aberation.
hope this helps