I wrote about this earlier. And I wondered if the correction made by the internal software of the Nikon D90 while converting to JPG has to do with the lens you use and if it has to be a Nikkor lens to get those results.

The corrections consist mainly in two actions: reducing the chromatic abberation and correcting lens distortion. And both of them are applied with my 14mm Sigma lens (which is quite a few years old and built for 35mm film cameras). I don’t know if the distortion correction comes from a database and/or from heuristic values, but I am quite sure that the chromatic abberation is corrected automatically — at least the lateral chromatic abberation. Although this article is about the Nikon D3x I believe that the technology mentioned in this paragraph applies to the D90 (and probably all other cameras labeled with “Expeed”), too:

[…] The lateral chromatic aberration correction will work with any lens, including those not from Nikon, because the correction applied is based on an analysis of the image data, not on lens information. If shooting NEF, the correction isn’t applied to the RAW data, but information about the analysis is, …

Chromatic Abberation in JPG produced with UFRaw, JPG produced by the Camera (100% crop)

This is a part of a photo shot with the D90 in RAW+JPG mode with the Sigma 14mm/2.8 lens mounted. The version without chromatic abberation is the JPG produced in the camera. The other one is produced by UFRaw without lens corrections.