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Why I Don’t Convert My Raw Images To DNG

Before, before we take this Genie out of the bottle, just a quick heads up: I am super excited to be one of the speakers again at the 8th Annual B&H Photo OPTIC conference (called OPTIC 2022 – It’s a conference for outdoor, wildlife, travel photography, and post-processing), and after a couple of years of doing it virtually, this year they are doing a hybrid event where it’s your choice – you can go and be there live in person as it happens at the New Yorker Hotel in Manhattan, or you can catch the conference online online, but here’s the best part – all you have to do is RSVP and tell ’em you’re coming (and, of course, choose in person or online). Registration is free. That’s it. You’re in. You get access to all the classes and goodies. Boom. Done. You should go RSVP right now (what do you have to lose?) – it’s going to be an incredible event.

OK, onto why I don’t convert my Raw images to DNG:

I’m going to try and keep this as short and sweet as possible, but it’s important to note up front — I’m not telling you-you shouldn’t be converting your RAW files to the DNG format — I’m just telling you I’m not, and I stopped doing it a while back. Here’s why:

Converting to DNG in Lightroom takes time, I don’t get much benefit back from taking that extra time and so for me and my workflow, it just doesn’t make sense.

None of the big three camera makers adopted the .DNG format
Only a handful of smaller companies did, so it never really caught on like it would have if they had all gotten on board. I don’t share files with other users where I need to keep my RAW edits intact when sharing the original RAW file with another user (see this article), so combining the .XMP file and the RAW original into one single file isn’t a benefit to me (I don’t work with XMP files that often to begin with). Plus, if I did convert to DNG for that reason, it takes longer to re-save the entire DNG file over again each time you make a change than it is to just save changes to a .xmp text file, which happens very quickly in comparison. It’s that wasting time thing again.

Am I concerned that one day I won’t be able to open my existing native RAW files created by the camera companies?
Not at all. At the time Adobe created the DNG spec, it was probably a legit concern, but these days a 12-year-old could probably write a RAW converter during study hall, so I don’t sweat it.

I know there are a handful of other pros of using DNG, but there are just as many cons. Maybe more.
I’m happy with where I’m at —  working faster, not wasting time on import converting to DNG, and I still sleep well at night. Something to think about, anyway. 🙂

Hope you have a great weekend, and we’ll catch you next week

-Scott

P.S. A few years back, one of my readers, Reid J. Thaler, did a really informative write up on why he doesn’t use DNG, and he posted it as a comment here on the blog. Here’s what he wrote:

FROM REID J. THALER:
I teach Lightroom and few years ago, I put together my own David Letterman style of “The Top Ten Reason Not to Convert Your Images to DNG Files”

1. Precludes you from using OEM software You will never be able to use your camera manufacture’s software again. Ever. Features that are specific to certain cameras (like Nikon’s Active D-Lighting and Picture Control) are not supported in the DNG format. Do you really think that Adobe knows everything that’s in every proprietary RAW file format it supports?

2. Backing up images will take longer In Lightroom, many of the changes you make can be stored in small XMP sidecar files that accompany raw files, and are only a few kilobytes. When you convert to DNG, changes are made directly to the file, so when you back up your images (hopefully daily) the whole file, typically 20 MB or more, needs to be backed up instead of just the small XMP sidecar files.

3. Metadata can’t be read by other software XMP data, including keywords, stars, and metadata that you may have changed in Lightroom is not available if you want to use another program that can read XMP sidecar files but not DNG files.

4. Longer downloading times from your memory card If you convert images to DNG upon importing to Lightroom, processing times increase since Lightroom must import and convert all the files to DNG.

5. File sizes One argument is that DNG file sizes are more efficient and can be up to 20% smaller. In 1956, the first IBM Model 350 hard drive weighed over a ton, cost $329,928 (in 2014 dollars) annually to lease, and stored 3.75 MB of data. It would have taken over 20 of them to hold a single Nikon D810 (36 MP) 14-bit RAW image file. Today, a 3 TB hard drive (formatted) holds the equivalent of 725,333 of the Model 350 hard drive and costs $100. The equivalent storage capacity, using the IBM Model 350 hard drive, would cost $14.9 billion to lease the same capacity (not to mention the 11.6 million square feet to store them, or the cost of electricity to run them. I’m not concerned about the size of native RAW files!

6. Load times DNG files supposedly load faster in the Develop module. With faster processors and Smart Previews, RAW files load very quickly in the Develop module even from an external drive USB 3.0 drive.

7. Ability to read RAW file in the future. One of the other main arguments in favor of converting to DNG files is that if a camera manufacturer stops producing software that can read their RAW files, then their RAW files would be unreadable. I don’t think Nikon, Canon, or Sony are going away anytime soon, and even if they were, you could use their software to read their files. Worst case, you could always convert them to DNG.

8. DNG is not an industry standard, it’s Adobe’s standard. As much as Adobe would love the DNG format to become the industry standard, it’s not. It’s Adobe’s standard. While a few camera manufactures produce camera the shoot DNG file as their native RAW files, most do not. DNG requires a lifelong allegiance to Adobe.

9. Camera brand not easily identified. Converting all your files to DNG makes it harder to quickly identify the camera manufacturer when looking at the file name since the suffix will be a generic DNG, and not one associated with your camera.

10. No obvious benefit. For all the reasons touting the DNG format, perhaps the biggest reason not to convert is that there is no obvious benefit. DNG files don’t contain more information (maybe less), are negligibly smaller, don’t load appreciably faster, take longer to download because the must be converted, and ties you to Adobe forever! They simply are, understandably, a greater benefit to Adobe than you, and have not been embraced as a standard format.

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11 comments

  1. Gilles 3 June, 2022 at 09:21 Reply

    As far as I know, Adobe owns only the “DNG” name, and has decided the format to be open and free, even for the industry. Remember that most of you use TIFF files without any complain, despite the fact that this format is owned by… Adobe.

    I don’t agree with the quote about the industry “standard”. DNG is the standard raw file in the smartphone industry and, therefore, it is potentially the most used raw file format in the world.

    The DNG format, which is not really a format but a container, is able to carry the proprietary data, even if 3rd party software can’t read it. And 3rd party software not able to read proprietary data in DNGs are also not able to read them in the proprietary (ie manufacturer’s) raw files.

    And, regarding the future of proprietary raw files, don’t forget that, in the past, some manufacturer’s tried to drop their own formats, even in their own software (remember Canon and it’s first version of DPP). And remember Nikon trying to hide some settings as encrypted data (remember the “white balance” affair). Nothing can stop them to do the same in the future.

  2. Ken Tannenbaum 1 June, 2022 at 07:24 Reply

    Microsoft Windows does not read / show DNG files in Windows explorer. It has no problems with my Canon CR2, Nikon NEF and Sony ARW files.

  3. Clive 30 May, 2022 at 08:28 Reply

    I made the mistake in 2016 of converting my old photos for the 10 years before, then stopped a few months later when I realised that I could not use some of Canon’s software, not done it since. Glad to hear you bringing the problems into the light.

  4. Harvey 29 May, 2022 at 21:34 Reply

    Staying with Canon CR2 files when using an infrared camera conversion lets me use the Canon proprietary software for white balance. The infrared white balance doesn’t get along well with Lightroom or Camera Raw.

  5. Chris Stone 28 May, 2022 at 23:16 Reply

    I shoot with Pentax, mainly with a Pentax K-3, and for over ten years Pentax has had the in camera option of writing the RAW files as either their native .PEF file format or as a DNG file when it gets written to the memory card.

    I’ve always used DNG and never had a problem with it. Works well with Lightroom Classic.

    And when I use Lightroom mobile, on my iPhone or iPad, the RAW files get saved as DNG files as well.

    Even when I shot with a Canon 5D Mark II the files got converted to DNG in the import process so ALL my RAW files no matter what camera I used were all in DNG format within the Lightroom ecosystem

  6. David 27 May, 2022 at 12:03 Reply

    With my Fuji files, I’m quite so trusting of the 12 year old. Especially since DXO took quite some time to do it.
    But, I like your thinking and I’ll give it a go – I can always convert them later if I have to.

  7. David Terry 27 May, 2022 at 11:21 Reply

    As a previous 14-year Canon veteran, I agree with all of the reasons NOT to use DNG. As a 4 year Sony shooter, however, I have a couple of very specific reasons for why I ALWAYS convert my Sony ARW files to DNG:

    1) Uncompressed Sony Raw files are HUGE. Every one of my 61mp a7Riv files are 120mb in size. And even the smaller 24mp a7iii files are around 48mb in size.

    2) Sony embeds a tiny little jpeg in their raw files. The embedded jpeg is so small that using an kind of image viewer to cull the files is impossible because you can’t see enough details in the image to know if an image is sharp or if eyes in big family group shots are open etc. (meaning the only way to cull is to use software that first converts the raw data to a viewable image and that takes time)

    Converting to DNG using lossless compression drops these sizes in half even while embedding a FULL SIZE jpeg inside of the DNG file. So you save disk space, you get faster load times, and faster/better culling outside of products such as Lightroom because you don’t have to interpret the raw data in order to cull.

    So yeah, I agree with all of the other reasons for not using DNG. But so long as I’m shooting Sony (unless Sony changes things) I will be converting all of my Sony raw files to DNG.

  8. Cliff Baughen 27 May, 2022 at 03:27 Reply

    As an aside, I found out this week that the Canon Connect Station CS100, that I use as one of my backup methods, does not work with Canon CS3 images i.e. the ones produced in the mirrorless cameras e.g. Canon R6. Canon Support said that they were not aware of any future support plans.

    • Greg 27 May, 2022 at 06:41 Reply

      How strange. I was looking into the CS100 earlier this morning for one reason or another. I’ve been aware of it for years but I never felt it a necessary accessory for me. I was hoping Canon may have updated it to be compatible with the image.canon service, but it appears we’re out of luck.

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