...
...If you wanted to investigate further, you could download either one of the Windows 'dcraw' compiles here:
http://www.centrostudiprogressofotografico.it/en/dcraw/ for "dcraw.exe" and use options: " -v -w -6 -T" which should produce a decoded raw file to 16-bit full-sized tiff with sRGB colors; camera WB; blended highlights; and auto brightness/contrast... ...however this "dcraw.exe" may not work with SNS-HDR algorithms when placed in the SNS-HDR program folder(s)... ...but may indicate that DCoffin's current dcraw9.26 does or does not support the 5Ds...
There is nothing that says you have to use SNS-HDR's raw decoding provisions... ..I routinely for
high quality prints will use either Canon DPP or Fuji RFC2.0 for my cameras' raw file conversions to 16-bit tiffs and input the tiffs to SNS-HDR for image blending and tone-mapping with a prefered and sometimes modified Preset... ...Note: SNS-HDR will process a single tiff [or jpeg] or a set of tiffs [or jpegs] as input(s)...
You may find that by doing so that you will have better resulting SNS-HDR images because of the camera specific
user accessible controls for reducing luma/color noise; optimizing lens characterics; and reducing lens aberrations, especially for DPP if you have downloaded the data libraries for the lenses that you have...
...have fun with your new camera...
...den...