3 Replies Latest reply on Mar 23, 2009 8:17 PM by ArrrBee

    DNG inflating file sizes

      I have seen a couple of explanations in here based on the 5d markii sraw issue, but when I convert files from either a 20d 1ds or 5d Mki I have the same issue,

      Here are teh options I have checked for DNG preferences

      Jpeg preview None
      Compression off
      Image Conversion Preserve
      Original Raw Un-checked

      On average a 7.6MB cr2 file from the 20d goes to 16.7Mb
      an 8MB file from the 1ds goes to 20MB
      and a 12MB 5d file is churning out a 25MB file

      Any ideas....??

      I'd avoid it altogether except I use DNG to force camera support in CS for the 5d and its breaking my heart how slow it makes the whole process

      Johnny

      Canon eos 1ds eos 5d eos 20d
      Apple iMac g5 20inch 2gb RAM
      Adobe Photoshop CS
        • 1. Re: DNG inflating file sizes
          ArrrBee Level 1
          The same thing happens with Sony A900 compressed raw files. I have found if
          I don't use the compressed raw but the regular raw that I will actually get
          smaller DNG files than the compressed raw file.

          Robert
          • 2. Re: DNG inflating file sizes
            Panoholic Level 2
            > a 12MB 5d file is churning out a 25MB file

            > Compression off

            > Any ideas....??

            Perhaps....
            i compression on?

            > I have found if I don't use the compressed raw but the regular raw that I will actually get smaller DNG files than the compressed raw file

            1. The Sony A900's "compressed raw" is not only
            i compressed
            but
            i weeded
            as well (in other words: it is
            i lossy
            raw). When converted in DNG format, the lossy data gets converted into lossless format (of course this does not make up for the inherent lossiness). Therefor the DNG format is larger.

            2. The "normal" (lossless) raw data of the A900 is compressed by "packing", which is the cheapest (fastest, but least effective) way of compression supported in raw files. When converted in compressed DNG, the more effective compression will be applied.
            • 3. Re: DNG inflating file sizes
              ArrrBee Level 1
              Thank for the info. But that wasn't my point. My point was that on rare
              occasions files sizes can be bigger and it has to do with the type of
              compression.

              Robert