I have not used my DP2 Quattro in a long time, mostly been using just the Fuji equip. But being a glutton for punishment I decided to play around with making some monochrome images with my DP2 Quattro. I looked at the Sigma site and they had new firmware which now includes the ability to output DNG files, so no more SPP for the X3F files. I installed it and it works great, I have been able to read and process the DNG files in a variety of converters. Just thought I would mention it, adds some much needed flexibility to these niche cameras.
Alan