Don Cooper , Dec 12, 2010; 02:42 p.m.
The NEF files are Nikon's proprietary format for RAW files. DNG is a file conversion utility from Adobe. Many people think that Nikon's NEF files contain more info than files converted to DNG. Many people use DNG as they are concerned that NEF files might not be supported sometime in the future. They convert the files to DNG as they feel that Adobe will be around longer than Nikon (I guess). Some users convert NEF to DNG as they are completely hung up on anything Adobe comes out with. People also us DNG to convert RAW files to usable files when the camera manufacturer comes out with a new camera that creates files that Adobe cannot yet read. You most certainly do not need to convert to NEF to DNG but sometimes it might help as mentioned previously (or in other ways that I'm sure someone will mention).