Roger Cavanagh has published a informative tutorial about combining 2 different versions of a RAW file to produce one image with greater dynamic range. He’s even created a Photoshop action to help automate the process.

“One of the advantages of shooting raw is that it is possible to convert the same image more than once using different conversion settings. Put another way, one conversion can be made for the highlights and another for the shadows. These conversions can then be combined to produce an image which has more overall detail and greater dynamic range.”

Website: Roger Cavanagh - Creating Composites