Hi all, am new here. I currently own a Nikon D80 with the kit 18-135, Nikon 50 f/1.8, Nikon 70-300VR and Sigma 10-20. I have had this set up for over 5 years and have considered upgrading for a long time. I wanted to move to full frame and purchased a D600 yesterday (still unopened). I am two minded as whether to keep it or not and wanted to know your advice. The only full frame lenses I have are the 50 and 70-300. The 18-135 I don't use whatsoever and the 10-20 is one I use quite frequently and like the filter option. The only full frame lens with a filter matching the performance of a 10-20 that I could find is the Nikon 16-35VR but is an extremely costly option. My question is, is it worth sacrificing the 10-20 to go full frame? If there were an affordable full frame wide angle lens with a filter thread this would not be an issue. Another question is, would the 50 still be good for portraits on a full frame or would you suggest an 85?