RAW vs DNG

ShinySideUp

ShinySideUp

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Martin
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I've had a look for similar subjects but can't seem to find anything specific.

Using Lightroom and seeing the import options led me to investigate the pros and cons of converting my Nikon NEF (RAW) files to DNG.

It seems that apart from the slight differences in what is and what is not, kept in the image file, the main decision seems to be 'which format has the greatest odds of being around in the future'.

Now I use Nikon cameras and lenses therefore I have NEF files. I know that so long as Nikon are around as a camera manufacturer their format will be supported both by their own software and that of others.

I know that Adobe don't make cameras and therefore presumably DNG will only be supported as long as Adobe are around to do image software.

At first glance there seems to be no contest as to which I should choose so as a lifelong Nikon user I should leave my picturres in Nikon RAW format, however...

...only Nikon have this flavour of RAW file and I have to rely on other companies to adapt to accept this format or I'm stuck with what Nikon supply.

I like the idea of DNG but if I convert my files I have kind of burnt my boats. I can't return them to NEF format, what's done is done.

So what do I do (assuming I don't want to keep both NEF and DNG files)? Convert or not convert?

What do you all do? (Herd-instinct here).
 
You can convert these at any time. You don't NEED to do it now. If Nikon are not around in the future, you still have your software that you use now to open the RAW images. You may even decide at some point in the future if things are going to change that you convert them to DNG at that time?

I don't see the point.
 
Just for info, one benefit is that any develop settings / Camera RAW settings that are used on the .DNG file will be saved into the file itself so if you lose your catalog or send the DNG file to another person, you can also transfer your develop settings without the need for the .XPM sidecar file.
 
the only reason to convert to dng for me is if camera raw doesn't support your camera. i.e. if you buy a new camera in a few years time then chances are camera raw won't support your raw file format so you then have to convert to dng
 
As I understand it (I don't use DNG files myself) it is possible to embed the original RAW file within the DNG file and these can be extracted later if required. Big files I would think, but keeps all your options open.
 
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Furtim said:
Just for info, one benefit is that any develop settings / Camera RAW settings that are used on the .DNG file will be saved into the file itself so if you lose your catalog or send the DNG file to another person, you can also transfer your develop settings without the need for the .XPM sidecar file.
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boyfalldown said:
File size (if storage is a consideration) is a big plus with DNG.
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Hi, These are two very good reasons to convert to DNG. There is also no loss of quality whatsoever.
 
john-oh said:
As I understand it (I don't use DNG files myself) it is possible to embed the original RAW file within the DNG file and these can be extracted later if required. Big files I would think, but keeps all your options open.
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Hmm, space is not a problem these days, I shall look into that.
 
I use dng as my ACR cant open my raws. The files are a little smaller as all the extra rubbish nikon puts in is removed. All tje picture info remains. So for me there is no point embedding the nef file. I dnt use view nx so the extra nikon info isnt required.

I wouldnt use dng if it wadnt for this purpose as its an extra step for take each time. And lets face is hdds are cheap now
 
Am I being too simplistic here ? I always copy and store all the RAW files on a separate storage device where they can live/be forgotten about happily ever after. Then convert the (odd ones worth keeping) original RAW files to JPEG and store them separately as well. Can't the same be done with DNG ?
 
barratt1988 said:
I use dng as my ACR cant open my raws. The files are a little smaller as all the extra rubbish nikon puts in is removed. All tje picture info remains. So for me there is no point embedding the nef file. I dnt use view nx so the extra nikon info isnt required.
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Afaik, the reason DNG files may be smaller than the original RAW file is because they compress it, (you would assume losslessly) rather than any info included by the manufacturer being discarded. If you embed the original RAW file then the DNG file will be larger.

Mag1cp2x said:
Am I being too simplistic here ? I always copy and store all the RAW files on a separate storage device where they can live/be forgotten about happily ever after. Then convert the (odd ones worth keeping) original RAW files to JPEG and store them separately as well. Can't the same be done with DNG ?
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Yes. :)

The plus points for me of DNG files are smaller file size, compatibility with most if not all RAW processing programs and the feature of saving any editing info into the DNG files, rather than as a separate sidecar XMP file, which needs to be kept within the same folders to be applied to the RAW file when opening again for editing.

That said, the only time I have converted files to DNG was when I needed smaller files to put onto a laptop before I went on holiday, or needed a file from newer camera to work with some older processing software. I kept the original RAW files on my desktop and external HDs.
 
redhed17 said:
Afaik, the reason DNG files may be smaller than the original RAW file is because they compress it, (you would assume losslessly) rather than any info included by the manufacturer being discarded. If you embed the original RAW file then the DNG file will be larger.


Yes. :)

The plus points for me of DNG files are smaller file size, compatibility with most if not all RAW processing programs and the feature of saving any editing info into the DNG files, rather than as a separate sidecar XMP file, which needs to be kept within the same folders to be applied to the RAW file when opening again for editing.

That said, the only time I have converted files to DNG was when I needed smaller files to put onto a laptop before I went on holiday, or needed a file from newer camera to work with some older processing software. I kept the original RAW files on my desktop and external HDs.
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There not compressed :s otherwise they wouldnt be raw
 
 
Interesting idea, Adobe and Nikon (and Canon for that matter) are pretty huge companies, I've never really considered a time when they wouldn't exist. Even if they did cease to exist their software would still be around though. Pretty sure I still have a really old copy of Dreamweaver kicking around somewhere from back when they were still Macromedia, I'm sure it would run on my computer.

I keep all mine as DNG in order to embed the edit and because they are smaller. They are still perfectly high enough quality so I don't tend to worry about it. Even if it gets superceded I don't think it matters, I think about it like an old camera, there might be better that comes out in the future but that doesn't mean what was there before wasn't any good.

If you are that concerned about DNG being lossey then why not keep everything as Nikon RAW and convert as and when you need to? Even if the companies that make the software go bust (or get bought out which seems more likely if it ever happend) you will almost certainly be able to find an old version of the software somewhere online.
 
OK, I have to admit some ignorance here. What is a sidecar or XMP file. I got the impression it was a file that was created when a picture was edited in a software program so I opened a file in View NX and faffed around with the contrast, cropping, sharpness, anything really then saved it back to the folder it came from and ta da... a picture just as I edited it was there with the same name and file extension. Where and when would this XMP file appear?
 
ShinySideUp said:
OK, I have to admit some ignorance here. What is a sidecar or XMP file. I got the impression it was a file that was created when a picture was edited in a software program so I opened a file in View NX and faffed around with the contrast, cropping, sharpness, anything really then saved it back to the folder it came from and ta da... a picture just as I edited it was there with the same name and file extension. Where and when would this XMP file appear?
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I'm not sure if View NX can save the list of edits as part of the original RAW file, or creates an XMP file.

Normally, you do some edits with something like Adobe Camera Raw, and click done, the XMP is created with a list of the edits applied to the file. If it remains in the same folder as the original RAW file, all the edits will be applied when the RAW file is opened again with the editing software. A DNG file doesn't make an XMP file because it also contains the list of all the edits, should you do any.
 
So the idea of a sidecar file is to keep the existing image but have another file that will change the picture to the way you edited it and without the sidecar file you will only have the original image? How is that an advantage over keeping the original file, editing it and then saving the edit as a new file, leaving you with two files just like having a sidecar file but now without the necessity to keep them bothin the same folder?
 
ShinySideUp said:
So the idea of a sidecar file is to keep the existing image but have another file that will change the picture to the way you edited it and without the sidecar file you will only have the original image? How is that an advantage over keeping the original file, editing it and then saving the edit as a new file, leaving you with two files just like having a sidecar file but now without the necessity to keep them bothin the same folder?
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The advantage comes when you want to re-edit the file to tweak your last edit, perhaps remove the contrast tweak, but keep all your other edits, or widen the crop a little. With the XMP approach you've still got all the information to you available from the original image, as well as the details if the, say, 50 or so 'edits' you applied, so you can adjust only what you need to do and move one.

With the two file approach - original plus edited, you run the risk of having to remember and apply all your edits to the original again.

Say you've spent hours tweaking and editing an image, select a final crop and save. A week, month or year later you decide you had been too harsh with the crop. You can't un-crop the saved edit as that information has perhaps been discarded (dependant upon your save format), so you have to start over.

You can mitigate this to an extent by always saving your edited files in an editable format; ie apply all your changes in layers so you can tweak later, and save with the layers intact. This however tends to produce files that are vey large, often many times that if the original. XMP files are normally a few bytes / kilobytes in size. Very small.

The third advantage is that XMP files are not usually seen, rather managed by the software so the process is invisible to the user, but this gives rise to the disadvantage that when you do need to faff around with the files themselves, they have to be kept together, and hence the advantage for DNG files that the sidecar files are effectively held within the DNG, hence no extra file but all the benefits.
 
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Thanks for that Furtim, makes a lot of sense and most enlightening.

Since I have to watch where my files and associated XMP's are, should I want to carry out extensive editing it does now make sense to use DNG. So I think my future philosophy is to keep the original format unless, I want to do extensive editing in which case I shall convert to DNG. Makes for a little extra care in file storing but nowhere near as much as if I had XMP's floating around (I do tend to change my filing systems regularly on a whim).
 
Furtim said:
The advantage comes when you want to re-edit the file to tweak your last edit, perhaps remove the contrast tweak, but keep all your other edits, or widen the crop a little. With the XMP approach you've still got all the information to you available from the original image, as well as the details if the, say, 50 or so 'edits' you applied, so you can adjust only what you need to do and move one.

With the two file approach - original plus edited, you run the risk of having to remember and apply all your edits to the original again.

Say you've spent hours tweaking and editing an image, select a final crop and save. A week, month or year later you decide you had been too harsh with the crop. You can't un-crop the saved edit as that information has perhaps been discarded (dependant upon your save format), so you have to start over.

You can mitigate this to an extent by always saving your edited files in an editable format; ie apply all your changes in layers so you can tweak later, and save with the layers intact. This however tends to produce files that are vey large, often many times that if the original. XMP files are normally a few bytes / kilobytes in size. Very small.

The third advantage is that XMP files are not usually seen, rather managed by the software so the process is invisible to the user, but this gives rise to the disadvantage that when you do need to faff around with the files themselves, they have to be kept together, and hence the advantage for DNG files that the sidecar files are effectively held within the DNG, hence no extra file but all the benefits.
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One other advantage of the raw + xmp method is that changing metadata on a large number of files just changes the xmp file. This means that any future backups will only need to backup the xmp file. Whereas if you make tha same changes to a large number of dng files, the backup will be much, much larger. This is of particular importance to me as one of my backups is online. Also note that this will make no difference if you do a full backup everytime, but most backup software wont do this type everytime.
 
I don't get why you'd convert either... Well.. I do actually, see later on.. but it's not something I do.


Futureproof? As the OP said, only as long as Adobe are solvent, which is just as likely as Nikon remaining solvent. Besides.. there's always something t convert files available. EVen if Nikon DO go bust overnight, the 'net will be alive with teh news, so you just convert them to something else while you still have software to that can do it. In fact, just because Nikon go bust doesn't mean software will no longer support .NEF. Photoshop still supports .IFF files!! Not used one of those since I had a Commodore Amiga :) I found some old Kodak Photo CDs the other week. No current image software supports .PCD files that I know of... it's been defunct since the start of the century. I still managed to find a free piece of software to convert them to TIFFs though. I can still download software to convert all manner of defunct file formats. You know when something's on it's way out, and you just convert to something else. It's not as if Nikon go bust, and then Adobe force you to update to a new version that no longer supports .NEF immediately.

I'm pretty damned certain there's no technical advantage to DNG other than the extra embedded data. Yes... having the ACR settngs embedded is a nice feature and negates your LR catalogue being lost, but most sensible people have back up... not just of their images, but their entire system. Those of you that don't... you should.

It's a personal choice I think. If you feel the embedded data is advantageous, then use DNG, if not, don't. I hardly do any editing in LR anyway beyond basic levels and curves, and in my case everything is so well backed up that it's massively unlikely I'll lose my LR catalogue. However... DNG stores the editing history in it's XMP file... I@m pretty certain. I still don't use it though. I don't process my images enough to care about that.


Horses for courses if you ask me. So long as both contain the full bit depth and all image data then it makes no difference.
 
The big advantage to me is file size. I always convert to lossy DNG when a job is completely finished. Doing so cuts my storage by about 2/3 and should I want copies for my own purposes they're unlikely to be more the web res so having the lossy files makes no difference to me long term.
 
DNG for me, smaller file size and all contained in one file.
 
DNG = how to tie yourself into Adobe IMHO. Whilst other software supports them, it appears to be glitchy occasionally from what I have read, plus you can't export the Adobe edits to other editing software.
 
I have never had any problems using DNG with other programs, Aperture for one.
 
boyfalldown said:
The big advantage to me is file size. I always convert to lossy DNG when a job is completely finished. Doing so cuts my storage by about 2/3 and should I want copies for my own purposes they're unlikely to be more the web res so having the lossy files makes no difference to me long term.
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I would never save anything in a Lossy format. Once the information has gone, it's gone for good.

Whatever works for you though. :)
 
redhed17 said:
I would never save anything in a Lossy format. Once the information has gone, it's gone for good.

Whatever works for you though. :)
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I can see that, but don't forget I have around 15,000 wedding images per year to save. Space becomes an issue, especially for files I'll never look at again. Horses for courses though
 
For my own pictures I like to have the images saved with as much info as I can, for anything I was getting paid for, and possibly have the opportunity to make more money from those files in the future, however slim, I would be saving the best quality I could.

As for the number of images, a couple of large HDs every year is not going to break the bank, and gets cheaper every year. And it is good practice to have back ups, and back up regularly too. Which I'm sure you're doing. ;)

You do what works for you though. It won't be the same as me, or anyone else in this thread. :)
 
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