I had heard that Nikon's software used to convert RAW images can extract proprietary information embedded in the NEF raw file. I must confess I was a bit skeptical. My workflow, up until now, has been to shoot in 14-bit raw (NEF) and convert to the DNG format using Adobe's software. The NEF files were kept as a backup and all post-processing was done on DNG raw files. I decided to do a little experiment to see what kind of extra information might be present in NEF that could not be teased out of a DNG file or its equivalent when Adobe did the raw conversion. For each shot, I started with the original raw NEF and opened it in Lightroom 4.4. LR converts the NEF on the fly and it is the same whether using Adobe Camera Raw or the Adobe DNG Converter software as far as I can tell. Alternatively, I opened the NEF in Nikon ViewNX 2 and converted to 16-bit TIFF format before opening in LR4.4, thus any proprietary information would have the advantage of the Nikon raw conversion. For each comparison, I made comparable 100% crops. My first experience was with a file from the D7000, but I thought maybe more recent cameras would not show the difference, so I tried the same experiment with my D7100 and D800E cameras (shown here).
With the D7100, the shot was taken under fluorescent lighting following a flood in my laboratory (f/8, 1/100 sec, ISO 1600, Auto WB). Like with the D7000, there are definite differences in white balance, sharpness and noise between the two, with the Nikon ViewNX 2 providing a superior conversion in my opinion. See if you don't agree. I was amazed, frankly.
With the D800E shot of a Sedona sunset (f/8, 1/200, ISO 200, Auto WB), I thought maybe this phenomenon would be less intrusive using a higher end, higher resolution camera. Not so! The Nikon conversion again produced significantly better sharpness and the chromatic aberration was much less apparent. Note the odd red halo bordering the top of the mountain silhouettes along with noise and WB differences in the Adobe LR conversion. Canon software may behave similarly I understand.
Take home message: Raw may not be raw and the results depend on the converter used and this has caused me to change my workflow. Now, I convert the raw NEF to TIFF via ViewNX 2 and open the 16-bit TIFF for post-processing.
Do these results surprise anyone besides me? I know one could probably get a DNG file to look like the extracted NEF, but if raw is raw, why don't they convert the same? Maybe a trivial point, but interesting to me nonetheless.