Over the years I’ve gone back and forth on this, so I was wondering if there was a general consensus here among NLP users.
Essentially, do you guys make it a habit to always convert your camera RAW files to DNG upon import into Lightroom? The theoretical pros being that DNG is supposed to be a more open source format and more future proof whereas proprietary RAW from canon/sony/nikon etc need to be supported by software etc. More real life pros is that the DNG files are smaller and take up less storage space. This is definitely true in real life for me, using a Nikon Z7II I just converted 34 files and the DNGs come in at 1.69GB, whereas the original NEF files totaled 2.94GB. This is a sizable difference, and the main reason I used to always do the conversion.
The theoretical downside is that you are still making a conversion and perhaps this would degrade the data or something so that it’s not as “Raw” as the original RAW files, even though the conversion is supposed to be lossless.
This is more of a general question but I guess I am also interested in whether this DNG conversion has down sides from a negative lab pro side of things? Does NLP do the exact same job on camera RAW as it does on converted DNGs? I suppose since NLP is essentially Lightroom, there shouldn’t be any downsides. But just curious, thanks.
I tested this and found no benefit in doing so. A few points need to be addressed though
file size…varies depending on which version of the converter is used. According to what I read (without looking for that information) is, that files converted with newer converters were smaller and that this reduction was based on some slight loss that seems to be acceptable to some. So far, I’ve always had enough space for original files (and backup copies!) on internal drives.
Metadata and customising recipes are written to DNGs, hence, there are no sidecars that can be lost, lost with all the info stored within them. On the other hand, how can we restore the original state of a freshly converted file if everything that was added later might not be easily removed?
What does the conversion to DNG do to an image? Supposedly nothing, but it seems that Adobe is adding hidden settings (as do other apps) that somehow contradict the paradigm of “original, unprocessed” image data.
Does it make sense to use a different DNG conversion instead of Adobe’s? Possibly. Apps like DxO PhotoLab can export DNG files that work flawlessly with NLP, even though they have undergone some processing like optical corrections and noise reduction at the cost of bigger files.
Imo and as a general rule, it’s preferable to let the original, OOC files sit on a storage medium and work is done on copies and/or without altering the file’s image, customising and metadata. Other than that, we simply cannot know when a SW-manufacturer pulls the plug on features or supported platforms which might make the one or the other format obsolete and/or unusable. We carry that risk ourselves and all we can do is to read the news and act accordingly.
I suppose you are probably correct. I guess it is just best practice to keep the original RAW. You can always convert to DNG for whatever reason in the future, but can’t really go backwards.
Has this size difference always been there for you? Pretty sure that I’ve read that the DNG conversion now uses the jpeg-xl algorithm (?) so that there are major file size reductions. I don’t use the subscription version but I believe there has been a massive reduction in size of Lightroom HDR & Panoramic photomerge DNG files as a consequence.
Interesting… I cannot say for sure if the reduction seems more now or not, I would say it has always been at least relatively significant, but I’d say though, that saving over 1GB per roll of film seems perhaps more than before. But can’t say with 100% certainty.
I never convert anything to DNG. My Panasonic raw files go straight into Lightroom Classic and stay there. I don’t save anything out of Negative Lab Pro, either. All exports are done from raw directly to 16-bit TIFF or PSD, in ProPhoto RGB, or 8-bit JPEG in sRGB, depending upon targeted usage.
20 years ago, I may have been concerned about storage space, network bandwidth, and processing times, but these days, I’m comfortable keeping my raw files intact, and making everything from them as needed. Resources are comparatively cheap in 2025.
At 69, realistically, I am not concerned about permanent access. I know that at some point, I may want to export everything I have edited to TIFF, just to get away from LR/PS and leave my kids what they might want to curate.
But to me, converting anything to DNG is silly. If it were such a great format, don’t you think ALL the camera manufacturers would have worked with Adobe to standardize it, so they could write to DNG in camera?
I think I read somewhere (RawDigger website?) that OEM RAW files may have proprietary information which is discarded when converted to DNG. So if you follow 2+1 formula for storage you may keep one copy as DNG just in case, but I would not do it being lazy. Also you may want to archive and keep handy the camera’s contemporary software ( if you or or your descendants) will ever have trouble opening raw files
I have a few family fotos that are >100 years old and happy about the pencil notes on their reverse. Maybe we need (to think about) physical prints more often.
RAW DNG has multiple versions of compression (both lossy and lossless) available since it came out, and the option for no compression. As of version 1.7.1.0 published 2023, it supports:
Deflate (ZIP)
JPEG, lossy and lossless
JPEG XL
It seems likely to me that significant filesize savings could be obtained with JPEG XL compression. It’s already in use elsewhere, eg for RAW photos with Samsung Galaxy S24 Ultra and S25 Ultra series flagship phones.
Dedicated cameras may not use any compression just because they don’t want to add a chip for it. Or they may implement only a small amount of compression so as not to add significant processing time needed between shots.
Neither matters once you transfer to your home computer, so I see no reason not to try to maximize compression as long as it’s done properly so it’s truly lossless.