7 Replies Latest reply on Mar 18, 2008 2:59 PM by Panoholic

    DNG Bit Depth

      Sorry for the basic question. What bit depth is the DNG file format? The RAW CR2 format from my camera is 14-bit, which seems a little odd. By converting to DNG am I losing any bit depth?

      Thanks.
        • 1. Re: DNG Bit Depth
          Panoholic Level 2
          Either 8 or 16. Unfortunately, there is no clean indication of the true bit depth of the data, one has to deduce it from WhiteLevel.
          • 2. Re: DNG Bit Depth
            Thomas Knoll Level 2
            DNG format currently supports any bit depth from 8 to 32.
            • 3. Re: DNG Bit Depth
              Panoholic Level 2
              All images I have seen with more than 8 bits are stored in 16 bits by the Adobe DNG converter, without indicating the original bit depth.

              However, the Pentax DNG files are in 12 bit format, packed; this results in larger files than the 14bit CR2 or compressed NEF files with the same or greater pixel count. Accordingly, the DNG converter is doing it right by sticking to 16 bit and compressing teh data.
              • 4. Re: DNG Bit Depth
                JimHess-8IPblY Level 3
                I might be (probably am) wrong, but it was my understanding that the DNG converter leaves the image data alone. Adobe Camera Raw opens the DNG file in a 16-bit environment, and then exports (or sends to Photoshop) the results in either a 16-bit or 8-bit file depending on how you have ACR configured.
                • 5. Re: DNG Bit Depth
                  If I'm using CS to work with DNG files, is there any concern about or limit to the bit-depth of the DNG images files I've converted from Canon 40d RAW files?

                  David.
                  • 6. Re: DNG Bit Depth
                    JimHess-8IPblY Level 3
                    Camera raw will open the images in whatever bit depth they were recorded in. You can choose to send those images from ACR to Photoshop as either 8-bit or 16-bit images. The 16-bit images will have greater tolerance for more aggressive adjustments. If you have an older computer, like I do, you might find that you work a little more sluggishly with 16-bit images. The other thing you will discover is that the tools available to you in 16-bit mode are somewhat limited. As far as I know, those are the only concerns.
                    • 7. Re: DNG Bit Depth
                      Panoholic Level 2
                      > If I'm using CS to work with DNG files, is there any concern about or limit to the bit-depth of the DNG images files I've converted from Canon 40d RAW files?

                      The DNG files created from a CR2 will always have 16-bit length. This is fine so, you can process these by ACR or by some other raw processor. This bit depth has nothing to do with the bit depth of the TIFF created by ACR or other raw converter; you can choose 8 or 18 bit TIFF.