4 Replies Latest reply on Jan 8, 2009 10:27 AM by (laurent_clevy)

    Canon sRAW to DNG Size Question


      I shot some images with my Canon 40D set to sRAW. A sample image size is 6.1 MB. In Lightroom 1.3.1, I convert the RAW (.CR2) file to DNG. The resulting DNG file is 6.7MB in size. The DNG Creation settings I used in the conversion were:

      JPEG preview: None
      Image Conversion Method: Preserve Raw Image
      Options: Compressed - ON / Embed Original Raw File - OFF

      I was under the impression that DNG format would be smaller than the RAW format.

      Is this larger DNG file because my original RAW file was a compressed RAW file (sRAW) and, as a result, the RAW image needs to be uncompressed before it is converted into a DNG file? If the original RAW image was NOT compressed, would I be seeing a reduction if file size after the DNG conversion.

      I guess the heart of my questions is this: Will conversion from RAW to DNG only provide a file size reduction if the original RAW file is uncompressed? Is it normal for me to see an increase in size when converting from sRAW to DNG, due to the fact that the original RAW file is a compressed RAW format?

      Thanks in advance for your clarification.