5 Replies Latest reply on Aug 14, 2012 10:25 AM by JimHess

    Why only 10-bit depth dng files from 16-bit Nikon D90 nef files?

    Sverk Level 1

      When I convert 16-bit .nef files from my Nikon D90 to DNG I get only 10-bits depth.

      Since the camera should be producing 12-bit depth it seems I am losing information in the conversion, and I don't want that.

      I have installed the 7.1 DNG converter, and I suppose that is what is used when I download from camera memory card through Bridge 5.1 and click dng conversion.

      Same thing if I open the .nef in Photoshop 5.1 , which kicks up CameraRaw converter 6.7.0.339.

      Why is this?

      Can't .dng have more than 10-bit depth?

      Sverk

        • 1. Re: Why only 10-bit depth dng files from 16-bit Nikon D90 nef files?
          JimHess Adobe Community Professional & MVP

          I don't know a lot about bit depth, but I do know that the D 90 only takes 10 bit NEF files. Lightroom and Camera Raw open those files in a 16-bit workspace. Some of the newer cameras are taking 12 bit images, but to my knowledge no camera is taking a true 16-bit image.

          • 2. Re: Why only 10-bit depth dng files from 16-bit Nikon D90 nef files?
            Sverk Level 1

            Well, according to the user manual and to the review in

            http://www.imaging-resource.com/PRODS/D90/D90A.HTM

            the D90 delivers 12-bit color depth in the .NEF files.

             

            Of course, I haven't looked at the actual pixel data to find out how finely graded they are.

            What I'm looking at is what Bridge 5.1 (WindowsXP) says about the files in the

            Metadata/ Bit depth entry. 

            In that, the .NEF files are listed as "16-bit" depth (although it will actually hold only 12-bit resolution), but when converted to .DNG it says only  "10-bit",

            and that holds both when the conversion is done automatically during the importing from the camera, and when converting from .nef files afterwards.

             

            Archiving pictures in the .dng format seems to be a good idea -- but only if no information is lost in the conversion.

            Thus, the "10-bit" info showing in Bridge worries me.

            Might it be that the meaning of bit depth is different in the two file formats?

            Might there be something about the de-mosaicing that necessarily consumes two bits of depth?   Whether in the .dng conversion -- or when saved .nef files are later to be used?

            In other words, for practical purposes, are the formats equivalent in color resolution,

            Or is there indeed a certain loss?

            Maybe a very difficult question, but I'd sure want to have a technical ly definite answer before I dare switch to using the .DNG format all the way.

            Sverk

            • 3. Re: Why only 10-bit depth dng files from 16-bit Nikon D90 nef files?
              JimHess Adobe Community Professional & MVP

              I stand corrected.  I knew it was less than 16 bits.  Don't know about the DNG.  I guess we'll have to check the DNG specification.

              • 4. Re: Why only 10-bit depth dng files from 16-bit Nikon D90 nef files?
                sandy_mc Level 3

                Without seeing the actualy files, I would think that what's happening is that the original NEFs were in Nikon's compressed NEF format. Compressed NEFs are level compressed, and have about 10 bits of effective resolution. When converted to DNG, Adobe keeps the level compression. In that case, you're not losing anything.

                 

                Sandy

                • 5. Re: Why only 10-bit depth dng files from 16-bit Nikon D90 nef files?
                  JimHess Adobe Community Professional & MVP

                  As it seems to happen all too often, I have replied without thinking again.  I'm using CS5, and the Bridge reports that my D90 NEF files are 16 bit.  I converted one of them to DNG, and it is reported as a 10-bit file.  Hopefully someone who knows will explain for us what is happening.