Like most amateur photographers, I started out with capturing my images with just JPEG. It does the job, it captures the image. However, JPEGs can be considered a final output. While there is alot that can be done to an image on JPEG, a raw file allows you to do more.
A raw file is basically information that has been captured via the image sensor with little or no modification done to that information. It is just light information as the sensor sees it. This is information untouched by sharpening, compression and any other post-processing settings set in-camera (ie: colour, contrast, etc.).
I started using raw to capture images when a friend wanted me to help him take some photos. Whilst raw has a few drawbacks (mainly storage related), it has way more benefits and that experience showed me what raw was capable of.
Thereafter, I used raw in all my photos, even personal ones. As you may already know, Nikon's raw format is NEF. For the first couple of years, I used NEFs, then I stumbled across Adobe Photoshop Lightroom and DNG. DNG is Adobe's solution to the raw format problem. Each camera manufacturer produces its own raw format. There hasn't been any real attempt at creating an industry standard.
DNG is supposed to fix this but based on its Wikipedia entry
, it doesn't appear to be very successful in urging camera manufacturers to support its format. I started exploring DNG purely because of Lightroom and the fact that I wanted to future proof my image library. Assuming DNG becomes an industry standard, then my digital negatives should be safe. However, recently I have had hit and miss results with software other than Lightroom when it comes to dealing with DNG and this has made me doubt this method of storing my photos.
So for now, I'm reverting to NEFs when storing my images and keeping a close eye on DNG's development.
For more info about DNG and raw formats, check out any of the links below: