21 Replies Latest reply on Jul 30, 2008 8:57 PM by (Jack_Joseph_Jr)

    Raw vs. DNG image quality

    Level 1
      Operating system is XP

      I have a Canon 40D with CR2 files that need to be read. I do not YET have Photoshop CS3. Still on CS2. The advice here has been to download the DNG converter that comes with the camera raw version for CS3.

      I downloaded and used the CS3 DNG converter which creates files that you can open in CS2 that are supposed to have all of the information / quality of your original CR2 RAW file.

      From what I can see, this is not the case. Converting the CR2 RAW files with the DNG converter appears to to discard color information and introduce artifacts. Here is one example showing the unconverted CR2 RAW image on the left (opened in Windows Live Photo Gallery) and the image after DNG conversion on the right (opened in Photoshop CS2). The color loss is obvious. The artifacts are most evident on the whiskers. I did a screenprint and saved the RAW & DNG together as a JPEG, but you can still see the difference:

      http://www.k9tag.com/rawvsdng.html

      Is it just me, or am I losing information with the DNG conversion? Would I lose this same information when opening 40D files with CS3 Camera RAW? Is there another utility that I should be using to open / convert my 40D files that will not lose information? I want my digital files to be all that they can be.

      -Mark
        • 1. Re: Raw vs. DNG image quality
          Panoholic Level 2
          You believe to compare the results from two different files. In reality you compare the results of two raw processors (ACR and the camera's firmware). The left side image is not an "unconverted raw image", it is the preview, created from the raw data by the camera.

          Sweet doggy, looks like a puppy.
          • 2. Re: Raw vs. DNG image quality
            Level 1
            So .. the whiskers look smooth on the left which means the data is there in the CR2 file. Why does DNG mess with the whiskers? Does ACR = DNG as far as how it opens images from the 40D? Is there a better program / utility for opening CR2 files that will not lose data?

            Yes, KIKI is a nice pup.
            • 3. Re: Raw vs. DNG image quality
              Panoholic Level 2
              I suggest you to go with these questions over to the ACR forum, as this is not a CR2 vs DNG issue. Though you should browse first, it's enough to read the titles to find related threads.
              • 4. Re: Raw vs. DNG image quality
                Level 1
                ?? This IS the ACR forum.
                • 5. Re: Raw vs. DNG image quality
                  Panoholic Level 2
                  Darn, I am sorry, I was just reading the DNG forum and you were talking about DNG

                  Ok, Mark, I was on the wrong place, not you.
                  • 6. Re: Raw vs. DNG image quality
                    Hudechrome-sd9sPI Level 2
                    Whew! Guess I am not the only one having Senior Moments these days!:D
                    • 7. Re: Raw vs. DNG image quality
                      Panoholic Level 2
                      I don't know how it is with you, but for me this is not restricted to these days. As I feel the pressure of time (of the remaining time), I try to deal with many things at the same time, and that leads to mix ups.
                      • 8. Re: Raw vs. DNG image quality
                        Omke Oudeman Level 5
                        As the 'older guys' already stated, you are comparing two things that cannot be compared.

                        I tried to find differences between DNG and a .CR2 file but even in the reds I could not find difference, even with pixel peeping using the pipet :-)

                        DNG is a save route that will give more certainty about future use because you can already convert this file in CS2 while the RAW file needs CS3.

                        It is a good idea to have a standard instead of hundreds of different RAW formats for each new digital camera.

                        Using Photodownloader in Bridge gives you different options about converting. I use a RAW back-up file to a separate drive and converting to renamed and copyrighted DNG file in one import action.

                        BTW, your nice puppy looks better in DNG, less saturation and contrast and nice detail in the shadows...
                        • 9. Re: Raw vs. DNG image quality
                          Level 1
                          I'm still not convinced that the DNG converter is producing optimal results for my 40D images. Here is another sample that contains the highest quality jpeg image available from the 40D on the left and a DNG conversion of the CR2 RAW file of the same image on the right. I didn't expect to see the artifacts that are visible on the close up of the DNG converted file on the right. The two close ups are shown below the two big images on this web page:

                          mega-scrolling is required to view the top two images ...

                          www.k9tag.com/ramses.html

                          I like the JPG better than the DNG which seems like it has artifacts that might show when the image is blown up and printed. Is it just me, or does the DNG conversion add artifacts? And if I had CS3 and opened the file in camera raw instead of converting to a DNG, would I see these same artifacts?
                          • 10. Re: Raw vs. DNG image quality
                            Panoholic Level 2
                            > if I had CS3 and opened the file in camera raw instead of converting to a DNG, would I see these same artifacts?

                            Mark, pls make a clear distinction between varying the programs and varying the file format.

                            ACR in CS3 is not the same as ACR in CS2. See some threads below about the integrated, non-negotiable noise reduction in ACR 4. I have not used ACR 3, but I heard that there are many other differences. So, the result between files created by ACR in CS2 will be different from that created by ACR in CS3.

                            However, if you process a CR2 file with ACR 4 and a DNG file converted from that raw with the same ACR, the results will be identical.

                            You are barking up the wrong tree with DNG. ACR delivers different result from DPP, no matter if ACR 3 or ACR 4.

                            Plus, you are comparing the ACR result with a JPEG created by the camera firmware. The latter has been created by applying the in-camera settings sharpening, contrast, saturation, color tone, and of course white balance. DPP would create almost identical result, because it applies the same settings (they are recorded in the raw file). ACR does not apply these settings, so you need to make the necessary adjustments.

                            You have to decide, which one you like more (or dislike less): DPP or ACR, but this should be a well-informed decision, based on experience. For example I find DPP's colors better, but ACR's adjustments are superior, and ACR's colors can be enhanced somewhat. Plus DPP has a browse function as well, ACR can't compete with that.

                            Finally, please note that there is no "correct" rendering of a raw file. There are many *different* renderings. The JPEG straight out of your camera is not the measure of rendering, it is one of them.
                            • 11. Re: Raw vs. DNG image quality
                              michael shaffer Level 1
                              > ... please note that there is no "correct" rendering of a raw file. There are many *different* renderings.

                              Altho ... one might come to the conclusion that the camera manufacturer knows demoaicing best. I also see artifacts present in my ACR developed ORFs not present if developed with the Olympus software. One has to decide which is more important, Adobe features and workflow versus small and infrequent buggering of the detail(?)

                              It caused me to wonder -- even if camera manufacturers shared their secrets, would Adobe offer a different algorithm for each camera?

                              cheerios :)
                              • 12. Re: Raw vs. DNG image quality
                                Level 1
                                Thanks for the input guys. Yes, let me clarify. I am using the DNG converter that was bundled with ACR4, not the previous version of the DNG converter. Then I open the resulting DNG files in CS2 rather than CS3.

                                Opening these converted DNG files with CS2's camera RAW, if I understand you guys correctly, produces different results that if they are opened by ACR4/CS3. Upon opening CR2 files directly with ACR4/CS3, I will see less of the little artifacts (possibly) because of improvements that have been made in ACR4.

                                I think that you are saying that some artifacts will still be around in CS3/CR4 and they are just part of the game. I can accept that.

                                I have not blown up any of the images and printed them on my 3800 so I am unsure if these little artifacts that I see in the DNG files will bug me when printed.

                                Yes, the 40D produces a nice jpeg within the camera using the DIGIC software. Yes, the CR2 raw file needs editing to improve the color, etc. I just thought for this example, I would put the unchanged jpeg and unchanged CR2 files on the web to view.

                                I am just looking for the way to get the best looking image from the camera for storage / later use.

                                I have the Real World Camera Raw book on order and will have CS3 soon. I will do some experimenting when I have both and print some large images and report back with comparisons of printing blown up jpegs and blown up CR2 files. I want the answer to be that the blown up RAW files always look better (after some tweaking).

                                Not sure what DPP is, but I assume it is probably the Canon software that I have not installed yet. Hey, good idea - I will install and see what that can do also.

                                Thanks again for your replys. -Mark
                                • 13. Re: Raw vs. DNG image quality
                                  michael shaffer Level 1
                                  > Opening these converted DNG files with CS2's camera RAW, if I understand you guys correctly, produces different results that if they are opened by ACR4/CS3.

                                  That may be the case for Canon files, but for my Oly ORFs, ACR4 yields the same results as ACR3 (all things being equal between the 2 versions).

                                  > I think that you are saying that some artifacts will still be around in CS3/CR4 and they are just part of the game. I can accept that.

                                  Altho I will get perturbed if the development destoyed detail that was otherwise resolved by an expensive lens. I accept that relative to all the other features and development control that ACR provides.

                                  cheerios :o)
                                  • 14. Re: Raw vs. DNG image quality
                                    Hi Everybody,

                                    I know Marks problem. I fixed the registry of Win XP, having thumbnail previews for my d40x NEF files as well as for the DNG files. After this, I immediately noticed differences in color depth and brilliance between the two thumbnails, nicely rowed next to each other after converting with DNG converter. This, regardless which version of DNG converter I used.

                                    With DNG converter I made two identical JPEG exports. The differences in saturation and color stayed clearly visible.

                                    Then I opened both RAW Data files with a trial version of CS3 and guess what....? No noticeable difference between these two files whatsoever in ACR 4.3! Exporting the two different RAW files into two JPEG files in ACR resulted also into two completely identical JPEG files.

                                    The only thing I can imagine, is that the newest versions of ACR that doesn't support CS2 (but come with a DNG converter that supports my D40X NEF's) produce DNG RAW files that can only be interpreted properly by CS3.

                                    This would make sense, but then again it remains unexplained why one can see these differences in Windows Explorer thumbnail preview as well.

                                    Nice regards,
                                    Corné
                                    • 15. Re: Raw vs. DNG image quality
                                      Panoholic Level 2
                                      >I immediately noticed differences in color depth and brilliance between the two thumbnails

                                      The thumbnail in the NEF file has been created with the camera settings (sharpness, contrast, saturation) applied; the DNG version is without.

                                      >No noticeable difference between these two files whatsoever in ACR 4.3! Exporting the two different RAW files into two JPEG files in ACR resulted also into two completely identical JPEG files

                                      This is good news (rather good olds). Why would these be different?

                                      >The only thing I can imagine, is that the newest versions of ACR that doesn't support CS2 (but come with a DNG converter that supports my D40X NEF's) produce DNG RAW files that can only be interpreted properly by CS3

                                      I can't follow your line of reasoning.
                                      • 16. Re: Raw vs. DNG image quality
                                        Level 1
                                        Kees Van Surksum,

                                        Can you explain a little more clearly what you think my problem is and how you think I can fix it?

                                        Thanks,

                                        Mark
                                        • 17. Re: Raw vs. DNG image quality
                                          Level 1
                                          Sorry guys,

                                          I didn't know about previews of RAW files showing additional camera information. I always thought RAW is "as it is".

                                          I tested the hypothesis and you are right. JPEG exports form ACR 3.7 in CS2 from a DNG and in ACR 4.3 in CS3 from a Nikon NEF RAW file look absolutely similar to me.

                                          So Mark, I guess you are right as far as loss of information in DNG conversion are concerned. But it seems to make no difference in which version of Photoshop and ACR.

                                          A good article on this subject you find at <a href="http://www.openraw.org/articles">www.opnraw.org</a>

                                          It seems we users of a 'prehistoric' CS2 and new non-supported cameras have to spend again on an update, or store our original NEF / CR2 files safely for a brighter future, in the meanwhile dealing with the next best ('cause that's what we're talking of, isn't it?).
                                          • 18. Re: Raw vs. DNG image quality
                                            In case someone comes back to read this topic, the problem with the loss in detail is due to the 44.5% image size in Photoshop. Photoshop only produces good images at 25, 50, 75 & 100% viewing size. This is due to how the software reduces the size and the algorithm is not perfect. Check out kenrockwell.com for a better explanation, and also try it yourself - images look horrible in odd increments.

                                            PS This problem seems to be prevalent more so in curved lines(ie whiskers).
                                            • 19. Re: Raw vs. DNG image quality
                                              Level 1
                                              Actually 75% is not one of the good ones. Basically any zoom level that can
                                              be divided by 2.

                                              Robert
                                              • 20. Re: Raw vs. DNG image quality
                                                Emperor Norton Level 1
                                                Curious as to whether anyone has done a comparison of prints.
                                                • 21. Re: Raw vs. DNG image quality
                                                  Level 1
                                                  Why on earth someone would want to use DNGs instead of CR2s is beyond me. Some photographers have written that they make DNGs and then discard the the originals. That is just plain nuts.

                                                  Come on, CS3 is just two-hundred bucks for the upgrade from CR2. The CR 4.5 beta with its simulated Picture Styles is outstanding and worth the two-hundred right there. Color rendition is much improved.

                                                  But DPP also does a fine job and I want the option to use both. Sometimes I've got my finished color version written to an xmp by ACR and a monochrome version saved in the CR2 file by DPP.

                                                  Just get CS3 and be done with it.