[Hdri] correction for barrel distortion

[Axel Jacobs]

The GIMP image manipulation package is available for OSX, and there are a
number of interesting plug-ins, including barrel distortion. Dunno if the
EXIF info is kept, but if not, you may just save it to a text file and
re-create an appropriate EXIF header once the dirty jobs are done.

There is also Hugin, a tool for stitiching panoramas. See here:
http://hugin.sourceforge.net/tutorials/perspective/en.shtml
how you can use it to correct barrel distortion. This is kinda
extreme-unbarrelling, though...

Axel