SumnerH said:
RAW is a well-defined lossless image format (it originated in Image Alchemy, and has the extension .raw).
Lots of modern cameras claim that they have raw image support, but in actuality they use other formats (Canon's .crw and Adobe's .dng are two common ones, but there are dozens). Calling them "raw" has become popular because that implies high quality images, but they aren't actually .RAW files. As a consumer, you should be pretty livid if you have a camera that purports to support RAW images but actually uses a lossy compression format--that isn't a RAW image, and should (IMO) be subject to false advertising or other fraud charges if the manufacturer claims their proprietary lossy format is raw image support.
A RAW image is a well-defined lossless standard (the first 6 bits will be "mhwanh" in ASCII or hex "6D 68 77 61 6E 68", followed by hex "00 04" (ASCII NUL and EOT) in both cases.
Hey, Sport, from page 334 of of the Nikon D600 User's Manual--Memory Card Capacity:
NEF (RAW), Lossless compressed, 12-bit -- file size: 23.4 MB
NEF (RAW), Lossless compressed, 14-bit -- file size: 29.2 MB
NEF (RAW), Compressed, 12-bit -- file size: 20.7 MB
NEF (RAW), Compressed, 14-bit -- file size: 25.4 MB
If Nikon wants to call them RAW files, I am not going to argue with them, much less be livid. It is a whole lot easier to just refer to my files as RAW instead of NEF when talking with other camera owners because each one has its own file extension name, e.g., CRW for Canon, PEF for Pentax, et al.
These many manufacturer-specific names for their RAW files generally have non-standard file headers, include additional image tags, and encrypt some of the file data in an attempt to prevent third-party software from accessing file content unless they are licensed to do so.
KiltedFool said: "RAW is apparently a big factor in the difference but I don't know enough to know what that translates to." I tried to provide an answer to that and your post on the
true meaning of RAW is rather irrelevant.