I have shot the D100 for three years a every one of the uncompressed RAW images are 9.6 MB. Why are there variations in the file sizes of the D2x RAW files if there is no compression (I am talking several hundred KB here)? I see some RAW as 19+ MB and others in the 18 MB range. Where is the extra data coming from?
I read the old post about where the numbers come from so understand that, but don't understand the variations.
The D100 uncompressed raw size do vary, but not by much. For example, I have two uncompressed D100 NEF files with sizes 9,538,222 and 9,482,249 bytes. This difference is due to a slight variation in the size of the embedded thumbnail JPG. The D100 has a 570x378 embedded JPG.
The D2X not only has a 570x375 embedded JPG thumbnail but also a full 4288x2848 embedded JPG. Therefore uncompressed D2X NEF file vary more in size than uncompressed D100 NEF files. My small sample runs from 20,187,584 to 20,558,616 bytes.
Why? As with much else about NEF, Nikon isn't saying.
Note that Capture actually updates these JPEG images when you save a NEF file after editing it. At least one program I'm aware of -- iVeww Media Pro -- extracts the large JPEG and uses it as the image since IVMP has no RAW processing capability. (I know of some Linux programs that use the JPEG, too.) So it's useful for at least some purposes.