DNG vs NEF/RAW with Lightroom

Discussion in 'Digital Darkroom' started by tom_luongo|1, Aug 18, 2007.

  1. Are there any downsides with Lightroom if I convert to DNG when importing from a
    memory card?

    I shoot NEFs and now that I can use Lightroom to import, convert, and rename in
    one-step, I'm thinking about throwing away the originals NEFs.

    I just want to make sure I'm not shooting myself in the foot. I'm also wondering
    if there is any performance difference in Lightroom between working with a
    folder full of NEF files and a folder full of DNG files.
  2. Some will throw their arms up in horror at the thought of ever throwing away a CR2/NEF - however - I've always done it the way you're suggesting, and have never had any cause for regret.

    I haven't had a play with Lightroom yet, but under Bridge, if you didn't convert to DNG then you ended up with a zillion *.XML "sidecar" files, which were a pain.
  3. I convert my NEF files to DNG on transfer from the card. As I understand it the original raw file (CR2, NEF, etc.) is embedded in the DNG and can always be recovered using the same DNG software. With this assurance I have seen no need to save the original NEF files. I have noticed that, after adjusting the DNG file in ACR it takes 4-5 seconds longer to process the data than it does when using the original NEF file. I am also happy to dispense with the XML sidecar files which accompany conversion of NEFs.

    I don't have Lightroom so I can't answer that question, but it causes no problem when using Adobe Bridge.
  4. I don't convert to DNG due to a couple of reasons:

    1. I don't feel that it is the golden standard just yet. I can always convert all of my photos later when (and if) it gets to that golden standard point.

    2. I don't understand your pains about the sidecar files, they don't bother me at all quite the oposite. They allow me to parse the info about the images to use for other purposes as well.

    3. I don't want to use lightroom as the master for image data due to difficulties with backing it up (much easier to backup the images). If I use XMP sidecar files it is a very quick process of writing metadata to the files but if I would be using DNGs it would take very much longer.
  5. Pontus:

    A couple of questions: Re #2: what do you mean by "parse the info for other purposes"; and how do sidecar files facilitate this?

    Re #3: Using Adobe Bridge to write metadata to the files, I find the process to be identical whether writing to NEFs or DNGs and the time required is the same. Am I missing something?
  6. Converting to DNG is to me one extra step with little or no benefits. The only reason I ever
    had for a DNG conversion was when I bought my D2X and was waiting for Photoshop CS2 to
    come out so I could edit my Raw. I would say it all depends on your work flow and what
    format you use for final storage. The only concern I would have with storing a NEF/RAW is
    over a long period of time say 10-20 years. The reason for this concern would be if that
    some future adobe product will support a file format for a used by an out dated camera
  7. Mike Blume wrote: "As I understand it the original raw file (CR2, NEF, etc.) is embedded in the DNG"

    Yes or no Mike - it's an options setting - if you choose to embed the original you essentially end up with 2 images in the one file, and twice the size.
  8. I recovered 30 gigs from my main hard drive by converting all NEFs to DNGs. They're smaller, but no loss of quality which I can see. I have yet to find a downside after making this leap myself.
  9. The potential downside is permanently losing compatibility with software that doesn't read DNGs, like Nikon's Capture NX (unless you embed the NEF in the DNG, which makes the file bigger but allows future extraction of the NEF). If you always intend to use Lightroom or ACR this won't be an issue.
  10. Vince, I suspect your space savings is from the size of the embedded jpeg preview. NEFs embed a full size basic compression jpeg. When you create a DNG you can select the size of the jpeg. Default is 1024x768 which saves a lot of space.

    For now, I'll stay with NEF. I'll be able to use Nikon tools if I want and I can always convert to DNG later.
  11. Mike:
    2) Since the XMP files are actually XML files (i.e. text files) it is very easy to extract the information for other purposes. Try opening an XMP file in an ordinary text editor (e.g. notepad) and you'll see. Personally I use this information as a standardized way of extracting information about images when creating web galleries. I know this is possible to do with other software but for me I wanted to customize things so much that I had to write my own software for doing it.
    3) I haven't tried writing metadata to DNG:s but I would be surprised if it is as quick as XMP:s. When you are updating metadata for a file and this change is to be written to the file (XMP or DNG), the entire file is re-written on the file system. Doing this on an XMP (2-3 kb in size) is obviously a much quicker process than doing it on a DNG (several MBs in size). Perhaps you don't see the difference when you are working on single files. Not a major issue but still...
  12. Pontus:

    Got it. Thanks for your answer.


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