Got 2 new lenses recently for my Pentax:
1) Sigma 70-300mm DG macro
2) An used Sigma 170-500 mm APO DG lens ... thanks to an old friend, i got this lens for 1/6th the price in calcutta...
Tried to take some snaps, results came out like this.
While reading came across this really great page on photography related tools on GNU/Linux
Currently i am using the Ufraw-CinePaint-Gimp pipeline on Debian/Sid and it works really well, at least for me.