Photoshop CS3 Tutorial
How to Convert Image to DNG Format in Photoshop
Every camera manufacturer has their own proprietary RAW format. Many photographers prefer to convert the RAW files to the DNG format early in the game to guarantee that their RAW files will open for several years and with all their image editing software.
In Photoshop choose File > Open... and navigate to your RAW images.
Click the Open button and the RAW dialog box appears.
Click the Select All button above the preview images.
Click the Save Images button in the lower left corner.
For format select Digital Negative. Set the file extension to .dng.
Choose a destination location and change the File Naming section if necessary.
Click Save and your images are converted to DNG. The original RAW files remain unchanged.