The P950 is a recent model that features in the current product line-up of Nikon. In contrast, the Df has been discontinued (but can be found pre-owned on ebay ). There has not been a direct replacement model for the Df from Nikon. Further information on the features and operation of the Df and P950 can be found, respectively, in the Nikon Df Manual (free pdf) or the online Nikon P950 Manual.