Two weeks ago, I posted about my naming conventions on the blog.  One eagle-eyed reader, Conor Molloy, noticed that the file extension I used in the examples was .dng, and Conor sent me an email pointing out one significant problem with using DNG that I wasn’t previously aware of.

So I thought this week I would spend a few moments going through….

The Pros and Cons of DNG (Digital Negative) Files

But first a little bit of history.  Every manufacturer has their own format for RAW files. There has been a lot of concern that as time goes on that RAW processing programs will no longer be able to process formats from older cameras thus making it impossible for photographers to reprocess images from 10, 15 or 20 years previously.

In response to this concern,  Adobe has developed the DNG format for storing RAW files.

A DNG file contains all the information from the camera sensor but translated to a common format. This means that any RAW converter that is capable of processing DNG files can convert images from any camera providing it has been converted to that format.

Standalone DNG converters are available, but Lightroom offers the option to convert images to DNG format as the files are being imported into Lightroom. I normally recommend that photographers should use this option.

Lightroom and DNG



It is a very easy step to convert your images to DNG format as you import them into Lightroom.  In the middle of the ‘ribbon’ at the top of the import dialog box, there are four options.  Copy, Move, Add and “Copy as DNG” this is the option I use.

Once the images have been successfully imported, Lightroom will start a background task to do the conversion.  Because the task is happening in the background, you don’t even have to wait for it to complete before starting to edit your images.   It should be noted that in earlier versions of lightroom LR5 and previous, the conversion happened during import so conversion to DNG meant a longer wait for the import to complete.  That is now no longer the case.

For existing files.  Select the files you wish to convert and choose the option “Library | Convert to DNG” off the menu in the Library Module.

In both, case any non-RAW files will automatically be skipped and will not be affected in any way.

The ‘Pros’ of DNG

DNG is primarily seen as a method of protecting images against RAW formats not being supported anymore.

Other advantages of the DNG format is that XMP data (which includes Lightroom processing settings) are embedded in the file as opposed to being stored in sidecar files. This means that Lightroom processing settings always stay with the RAW file.

DNG files are also very slightly smaller than their RAW counterparts and so offer a slight saving on disk space.

The ‘Cons’ of DNG

I always used to say that I couldn’t see any ‘cons’ other than the fact that it took longer to import into Lightroom.   And as mentioned above that downside went away with the release of Lightroom 6/CC.

However, this brings me back to the email I received following my recent blog post on naming conventions.  If you are a wildlife photographer (now you know why there is a photograph of peacock as the image for this blog post) then you need to be aware of something.

The Nation History Museum’s Wildlife Photographer of the Year competition requires that you submit the ORIGINAL RAW file as proof that the image has not been manipulated.  They will not accept DNG files, even if they have been converted immediately out of camera.  According to their website: with a DNG file they are “unable to check if any digital adjustments made fall within the competition rules.”


Apart from wildlife photographers… actually let me rephrase that… apart from wildlife photographers who are thinking about entering the “Wildlife Photographer of the Year” competition, I still can’t see any downsides to converting to DNG.

If you are a wildlife photographer, my recommendation is that you still convert to DNG – it will future proof your images – but I also recommend that you keep a copy of the original RAW file for your wildlife images.  The easiest way to do this in LR is to use the “Make as Second Copy To” option on the import dialog box.  This will make a copy of the original RAW file in the location you specify, the version in Lightroom will still be converted to DNG.

My thanks to Conor for bringing this to my attention.  If you would like to see some of Conor’s stunning wildlife images you can find them on his website here:

Until next time, keep MAKING great images,