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Adobe DNG file size

Discussion in 'Image Processing' started by Luckypenguin, Aug 27, 2011.

  1. I've been converting RAW files to Adobe DNG for a while now, but I am having some issues with excessive file size of the converted DNG. My Olympus and Panasonic RAW files generally are around 12Mb, and usually the converted DNGs come out around the same size. I can't quite determine when or how the change occurred but I seem to now be consistently ending up with files over 40Mb. One converted GH1 file I just found was 52Mb! I'm choosing to not embed the original RAW so that should not be an influence, and for that matter I don't recall having changed any of the program settings in Adobe DNG Convertor (v6.4). The larger DNG files still open up inside Photoshop with Camera RAW with no problems, so heaven knows what the extra 30-odd Mb of data is doing.
  2. jlabate

    jlabate Mu-43 Regular

    Nov 22, 2010
    There's a window in ACR that allows you to interpolate the files. Several options to make them smaller or bigger. It's also the window that allows you to assign a color space to the file. Worth checking to see how it's set although I don't know how it would have changed without you knowing. To open that window click on the "link" towards the bottom of the ACR window.
  3. Thanks for your response. While checking out the options in the ACR window with some different files, I think I found what the problem is.

    From a bunch of GH1 RAWs I converted in a batch there was a mix of small ~10-12Mb files and large ~40-50Mb files, and I realised that all of the small files were of images that I took using a 50mm OM Zuiko lens. All of the larger files were taken using the native 9-8mm and 14-140mm lens...which require software correction for distortion. It's only really been in the last few months that I have started to shoot mostly with the native lenses which is probably why I didn't notice the issue earlier.

    At the moment I am am converting using Adobe DNG Convertor to the ACR 4.6 compatible file format because I am using an older (CS3) photoshop. I might try converting them to the later ACR 5.4 format and see if I can still work with the files and if the file compression is more efficient for software RAW correction data.
  4. DekHog

    DekHog Mu-43 Top Veteran

    May 3, 2011
    This is very interesting, I must have a look at some of my own DNG v ORF file sizes. I always convert to DNG, especially since my old Fuji S5 Pro used to produce 25Mb RAW files from an effective 6Mp image, and converting them to DNG would cut that size by around 50% without any loss of quality or (that fantastic) DR at all.

    In fact, I've never heard of DNG files being larger than the original files anywhere, although I'm guessing that your version of ACR might something to do with it.
  5. I hoped it might have been the case...but I just tried converting to the latest ACR format (which it turns out my old ACR 4 still reads anyway), and the files still come out at > 40Mb. This is happening with files from the E-P1, E-PL1, and GH1, using the M Zuiko 9-18 and 14-42 II , and Panny 14-140mm lenses. As noted earlier it does not happen with non-native lenses (including 4/3 lenses), which actually result in ever so slightly smaller files.

    The bloated file size occurs during the initial conversion by the Adobe DNG Convertor, not within Adobe Camera RAW
  6. pictor

    pictor Mu-43 Top Veteran

    Jul 17, 2010
    I have converted all my raw files to DNG lately. I have checked some files I took with my 9-18mm (on an E-PL1) and everything seems to be fine. The sizes of the files are not smaller than the native raw files because I create full sized preview pictures, but I do not use DNG because of file size. I convert all of my raw files to DNG in Lightroom after developing the raw files. If the exported JPEGs are ok, I will format the SD card with all the native raw files. I never use the standalone DNG converter.
  7. Correction to my previous post, converting to the later ACR format DOES create a smaller file size. My previous test was to convert one of the bloated DNG files to the later format (which did nothing), but converting an ORF file did create a smaller size DNG.

    So...any file that I have already converted is a lost cause (in that it will remain 4x too big), but the problem should be solved for anything from now on as long as the latest ACR format is selected. Since my older PS/ACR still reads the latest format, I'll do that from now on. Lesson learned :redface:
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