You’re probably wondering why this DP3M doesn’t look anything like the press release photos – my friend attached a RRS grip and plate to it, and rightly so; without it, the camera is not very comfortable to hold.
I eventually caved to both pressure and curiosity, and borrowed the Sigma DP3M from master printer and good friend Wesley Wong – who has the DP Merrill in all three flavors. In case you’ve been living under a rock for the last few years, Sigma has been going their own way with the DP series of large sensor compacts; all of their cameras now share the same 14.7 MP (effective) three-layered Foveon sensor, with a 4.99 micron pixel pitch and true color/ true resolution information across all photosites. In a nutshell, the difference between Foveon and Bayer sensors is that the former records actual RGB values for each pixel, but the latter only records R, G or B, interpolating the other values from neighboring photosites. It’s difficult to determine precisely just how much resolution loss Bayer interpolation causes, but in my experience it seems to be around 50% or so. Sigma claims that the camera has the equivalent of 46MP (being 15.3 total MP x3 layers) – but this is really pushing it; images upsampled this far simply do not have the pixel-level ‘bite’ of a good Bayer file.