11 Replies Latest reply on May 6, 2010 1:11 PM by Greg Barnett

    'DNG-back-to-X' or 'reverse conversion'. Do you think it's needed ?

    bokeron2008 Level 1

      I'm sure this has been discussed before, but I still need to speak my mind


      I believe a "reverse DNG converter" is not a convenience but a necessity.


      I've come to the conclussion, from what I've observed since I use DNG myself, that having this converter would eliminate the two main reasons I find people still have to not use DNG.


      The main fear I've observed is that A LOT of people have the impression that Adobe pretends to lure them into a trap, 'slaving' them to an Adobe format instead of their camera format : just a change of master, but remaining a slave just the same. Their reasoning is 'why change, there are no advantages freedom-wise'.

      Added to this, a lack of real/full support of the DNG format in software outside of Adobe reinforces that perception: they feel they're forced to use an Adobe product from the day they start using DNG.


      The other one is caused by disinformation : Most people believe they lose data in the process of conversion. This is also reinforced because all non-Adobe software fail to read the propietary info, maker notes, inside the DNG file.


      A 'DNG-back-to-X' converter would end the discussion instantly. This would not only ensure them that they can go back at any time they wish, no harm done, but they could test if their data is conserved back-and-forth, finally understanding that no data is lost and that the only problem is software companies not fully understanding/supporting DNG.



      They reason often given for not having this reverse converter is technical. I believe it can be done ... if Adobe wants to make a point having it done.

      I'm no engineer, but I have the perception that though it may be difficult, they main reason for not having it done is that Adobe feels there's not enough benefit from it and their resources are better employed elsewhere.


      With this message I just wan't to expose MY reasoning of why Adobe needs to address this.


      What is your oppinion on what I've just said ? Do you think it would be a welcome tool ? Do you think it is technically possible to do it ?



      Thanks for reading my poor excuse of an analysis

        • 1. Re: 'DNG-back-to-X' or 'reverse conversion'. Do you think it's needed ?
          JimHess-DIrcbP Level 3

          First of all, I believe that those who are skeptical of using DNG are going to remain skeptical regardless of what Adobe does.  I have read enough discussions over the years and read the comments of the skeptics who always say, "you can't tell me that" and the argument just goes on and on.



          In order for Adobe to re-create those original raw files it would be necessary for them to know the exact file structure, and have the capability of creating the file structure including any proprietary fields.  At least that is my understanding.



          Why worry about whether people are afraid of DNG anyway?  I have used it in the past, and occasionally use it now.  Most people use the argument that they don't want to deal with XMP sidecar files, so that is why they use DNG.  If Lightroom is used in its default configuration, XMP files are not created even for the original raw files.  So I have yet to convince myself of any real value in converting to DNG on a routine basis.  I know, others will argue just the opposite.  The only time I really see the need for DNG is if I receive a raw file that my version of Lightroom or Camera Raw cannot process.  But, that's just my opinion.

          • 2. Re: 'DNG-back-to-X' or 'reverse conversion'. Do you think it's needed ?
            Greg Barnett Level 2

            >I'm no engineer, but I have the perception that though it may be  difficult, they main reason for not having it done is that Adobe feels  there's not enough benefit from it and their resources are better  employed elsewhere.<


            I put in a feature request for reverse (un-conversion) encoding back quite a while ago. But as you indicated, I suspect that the use case is pretty low on the priority list. And as much as I'd like to be able to ditch my archived original raw files because I could reconstitute them from the DNG's, I'd much rather see the engineering time going into the stuff they've been doing like lens corrections and the excellent new noise reduction.

            • 3. Re: 'DNG-back-to-X' or 'reverse conversion'. Do you think it's needed ?
              bokeron2008 Level 1



              I use DNG because, apart from the normal metadata cuestion, it saves me from having original and (multiple) final versions of the image. All the edit steps and therefore all the version of the image, can be contained within one single file.

              It can do that for Lightroom, and it could do that for any other program that chose to save the processing steps inside the DNG file instead of on an internal database. For me it solves a lot of archiving problems.


              BUT I need it to succeed, or all the advantages of using it now will turn into headaches in the future when no one apart from Adobe really supports it.


              In your answer I find the same 'barrier against DNG spread' problem I'm talking about. DNG is, in each and every aspect, a better format than any propietary RAW file, and the benefits of having to manage just one format are many ... yet you don't find the need to use it as the main filetype in your workflow.


              I believe that, if 'de-converting' were as easy and trivial as converting to DNG, you would indistinctly use any of them. Right now, as you said, have to be convinced to use DNG... because it has tradeoffs.


              Being able to convert and de-convert would wipe any tradeoffs and need-to-be-convinced.



              Greg Barnett :


              I obviously enjoy having better noise reduction and lens corrections too. But that can be done with many other tools.


              DNG conversion and de-conversion foundations must be done by the 'fathers' of the format. It can't be done by anyone else, and it needs to be done or DNG will lack a solid and trustworthy roots to grow further.

              Any doubt about being a wise move to convert to DNG or not must be erradicated in order to be adopted without remorses, and the most important step is, more important than denoising algorithms from my point of view, to tell everyone - you can trust us with your image, we are TRULY open, we won't held your images hostages, you are free using DNG and here's the proof.

              • 4. Re: 'DNG-back-to-X' or 'reverse conversion'. Do you think it's needed ?
                Greg Barnett Level 2

                I don't disagree but do have some knowledge of how Adobe establishes priorities for feature development. And unfortunately, the engineering team that supports the DNG/CR/LR processing pipeline is quite small. So I suspect that it's a constant juggling act for them to divide their resources between mainstream feature development and tweaks to the DNG spec and feature set. But beating the drum for further improvements is a good thing!

                • 5. Re: 'DNG-back-to-X' or 'reverse conversion'. Do you think it's needed ?
                  JimHess-DIrcbP Level 3

                  I don't believe that DNG is a superior file format "in each and every respect" as you indicated.  When working in Lightroom switching between the raw format of one camera and another is completely transparent.  I work with Lightroom with its default setup where the changes are stored in the Lightroom catalog rather than in the file.  In my opinion, since I don't have any other software that will do anything with the DNG file, that setup is good enough for me.  There aren't many occasions when I would want to do this, but occasionally I like to look at an image in ViewNX, a very basic editor provided free from Nikon.  If I convert to DNG, I cannot use that viewer.  Yes, I know, that probably isn't a big deal.  But one of the benefits of ViewNX is that I can see what focus points in my camera were utilized.  Again, not a big deal.  But if I have a problem image with focusing, for instance, I can use the other program to discover what I did wrong.  Processing the image in Lightroom is no different.  I see no advantage to the DNG file.



                  I'm not trying to dissuade anyone from using DNG.  I just have not been convinced that it is the superior file format that some people believe that it is.  There is nothing wrong with using it.  But, for me, it doesn't offer any real advantages.  That's why I said what I did in my previous response.

                  • 6. Re: 'DNG-back-to-X' or 'reverse conversion'. Do you think it's needed ?
                    Greg Barnett Level 2



                    I think you'll find than many of us who have embraced DNG have a strong aversion to the proprietary aspect of OEM raw formats. While I certainly enjoy the workflow advantages (at least in the Adobe space) of DNG, personally, it's more of about the philosophical issues surrounding the control over my image data. Simply put, I want my files in an openly documented format. It's also why I use TIF rather than PSD in Photoshop.


                    Going back to my analog roots, once I processed a negative or chrome, all of the "image data" was under my control. Having a modern day camera manufacturer tell me that they know what's best and to trust in the integrity of their proprietary files is just not acceptable. I'm sure that none of this is really news to you or anyone else who follows this forum but it just goes to show how far we still need to travel to get these issues resolved.




                    • 7. Re: 'DNG-back-to-X' or 'reverse conversion'. Do you think it's needed ?
                      JimHess-DIrcbP Level 3

                      I will agree that proprietary raw files are a real pain.  I use Nikon cameras.  I am NOT in love with the NEF file format.  But converting them to DNG isn't doing anything to Nikon and isn't going to change anything.  You still have to deal with the NEF or CR2 or ORF or RAF or what ever, at least long enough to convert them to DNG.  Fighting the proprietary file for that reason alone, that you don't like having to deal with it, is like spitting in the wind.  You're not really accomplishing anything.  You are not changing Nikon's or Canon's business philosophy.  But I realize that you do have your principles.  I understand the frustration.  In the past I have had to wait for ACR to support a certain raw image format.  And I'm not criticizing anyone for using DNG.  I just don't believe it is the "clearly superior" format, as has been suggested.



                      I think if I was using Photoshop/ACR rather than Lightroom that I would probably prefer DNG to NEF.  I don't like having to worry about XMP sidecar files.  In fact, before I started using Lightroom, I routinely converted to DNG for that very reason.  And I would read complaints in the forums that they didn't want to bother with that extra step of conversion to DNG.  And my argument was that it is necessary to download the images anyway.  So using the DNG converter didn't really complicate the workflow.  And I couldn't understand why a lot of people objected.  Additionally, with the camera I was using at the time, converting to DNG reduced the file size by about 50%.  Now, there is hardly any file space savings.  And while I don't like worrying about what version I have to have in order to support my camera because of the arrogance of the camera manufacturers, I don't think DNG is worth the bother.  But, that is only for me, and is only my opinion.  Carry on!  Win the war!  Someday it will all be different. 

                      • 8. Re: 'DNG-back-to-X' or 'reverse conversion'. Do you think it's needed ?
                        Greg Barnett Level 2

                        >You're not really accomplishing anything.


                        Actually, there is one very tangible benefit that you get right off the bat (which is why I convert before doing anything else) - image data verification. If there is a problem with your originals, the conversion process will reveal that. And there is also the additional benefit of the data validation hash that was added to the last rev of the spec. So I find that to be another compelling reason to use the format. Not trying to "convert" you, just pointing out things that other users may not be aware of.



                        • 9. Re: 'DNG-back-to-X' or 'reverse conversion'. Do you think it's needed ?
                          bokeron2008 Level 1

                          As interesting as debating the merits and demerits of the diverse formats vs DNG is, I would ask we tried to keep the focus on the reverse-converter issue.

                          By the way, maybe I should reword the 'in each and every ..' to something less categorical. Let's just say it offers a lot of advantages over other formats.


                          My point is not to demonstrate how superior DNG is, but to express my point of view about how greatly a reverse converter would help to diminish current reservations about using it as a standard archiving format, and to read other people's about this question ... though it will make for a much less interesting debate than 'DNG vs. the world'.


                          Example : JimHess has a colection of 120.000 pictures. He backs up his mix of differente NEF files to an external HDD. The develop settings are kept inside LR database. So, in case Jim's PC crashes, he has to back up the database too or he will lose all the image settings. With DNG he only have to back up the images, and the settings are saved inside them. The next time Jim's PC crashes he just need to reimport the images, and all the modifications are as they were again, nothing was lost.

                          That's one of the strenghts of DNG so far, until NEF documents the format enough to allow risk-less writing of metadata inside the file.



                          BUT ... JimHess won't use DNG because he sometimes need to use a Nikon program and he needs NEFs for that. Would a reverse converter give him the ability to benefit from the best of both formats without having to suffer any of the shortcomings ?



                          This is my point. Would a reverse converter help stablish DNG as a trusted, standard, archival format, or not ?

                          • 10. Re: 'DNG-back-to-X' or 'reverse conversion'. Do you think it's needed ?
                            JimHess-DIrcbP Level 3

                            But, even if Jim Hess had converted everything to DNG, it wouldn't have made any difference.  Jim Hess uses the Lightroom default setting where the changes are stored in the catalog, not in the DNG file.  So the DNG files would not contain the changes and therefore would have to be redone.  Yes, there is an argument for writing changes to the files, I understand, but I don't do it that way.  I also understand the risk I'm taking.  But, you are concerned about keeping things on topic, I will stop commenting in this thread.

                            • 11. Re: 'DNG-back-to-X' or 'reverse conversion'. Do you think it's needed ?
                              Greg Barnett Level 2

                              >This is my point. Would a reverse converter help stablish DNG as a trusted, standard, archival format, or not ?


                              Again, no argument from me on the orginal issue, I fully agree! But the debate has merit and illustrates that trust and adoption are viewed from a number of different perspectives.


                              Since there is no dedicated feature request forum for DNG, you might want to submit this over in the Camera Raw FR forum. The same engineers and product management folks work on both. I'm sure they keep an eye on this forum but things do get pretty quiet over here....