14 Replies Latest reply on Aug 6, 2007 5:33 PM by (steve_krepps)

    ACR 4.1 compression when converting to .jpg

      my 10mb canon cr2 raw files are compressing to 4mb when maximizing jpg image settings (using 12)and 300ppi. this seems like a lot of compression and data loss.

      anyone else experiencing this?
      is there something I can change?

      typically in previous versions of acr i'd get a a 6-7mb jpg from an 8mb cr2 file.
        • 1. Re: ACR 4.1 compression when converting to .jpg
          Thomas Knoll Level 2
          Save out both a TIFF file and a quality 12 JPEG file from Camera Raw. Open both in Photoshop and copy/paste one of them into the other and create a two layer document. Zoom into 100% view and toggle the top layer visiblity on and off. Can you see any difference? Do you care about the difference? If so, don't use JPEG format. If not, why are you complaining about "data loss"?
          • 2. Re: ACR 4.1 compression when converting to .jpg
            Level 1
            Thomas,
            So you are comfortable w/ a 10mb file compressing to 4mb jpg when in the older version of Adobe CS2 and RAW 3.7 an 8Mb converted it to a 7mb jpg?

            Also, Canon's RAW converter gets me a higher quality 7mb .jpg than Adobe. Does that make sense to you?

            You're not understanding my question. I understand that Tiff much like RAW, having all the data and .jpg losing data. I'm looking for a better quality .jpg like I experienced before in previous versions of Adobe software. There is a big difference in a 4mb and a 7mb jpg at a 100% zoom.

            Any explanation for for quality loss and data loss in Adobe CS3 Raw 4.1 compression scheme?
            • 3. Re: ACR 4.1 compression when converting to .jpg
              Ramón G Castañeda Level 4
              Steve,

              In my reading TK's message, I don't see anything to indicate that the creator of Photoshop and of Adobe Camera Raw is advocating using JPEGs nor saying that he would be "comfortable" with anything. I would read his post gain, if I were you.

              Sorry, I can't give you any further input or elaboration, as that would be ludicrous after Thomas Knoll has already posted in this thread and also because I don't use JPEGs other than to create a small file to post on the web to illustrate a point.
              • 4. Re: ACR 4.1 compression when converting to .jpg
                Level 1
                Ramon,

                I understand his post.

                I use an online print service that requires a .jpg. Again I understand the difference btwn other full data formats such as tiff, psd etc. and .jpg.

                Look at the math of the file sizes. It doesn't add up. And previous version of Adobe didn't produce a lesser quality .jpg like ACR 4.1 does.

                I mean, Canon has a better Raw converter at this point. Does that make sense to you? Isn't new versions of Adobe software supposed to get better, not worse?

                Steve
                • 5. Re: ACR 4.1 compression when converting to .jpg
                  Level 1
                  Ramon, are you and Thomas Adobe employees, or just avid fans who never have the need for .jpg. Just curious.
                  • 6. Re: ACR 4.1 compression when converting to .jpg
                    Ramón G Castañeda Level 4
                    Steve,

                    Thomas Xnoll is the creator of both Adobe Camera Raw and of Camera Raw.

                    That's what I wanted to point out to you. Look at your Photoshop splash screen.

                    These are fundamentally user to user forums. You are NOT addressing Adobe here. We are all users just like you.

                    We are extraordinarily fortunate to have Thomas Knoll active in this particular forum as a volunteer and on his own time.

                    Adobe does not monitor these user to user forums otherwise. If you have a gripe and you want to complain, whine or rant, contact Adobe directly. Use the Contact button at the top of this page.

                    I do not work for Adobe. And I do avoid JPEGs as a general rule, except for the purpose stated above.
                    • 7. Re: ACR 4.1 compression when converting to .jpg
                      Level 1
                      Ramón...pretty sure Thomas spells his name Knoll.

                      And steve...yeah Thomas does a few things for Adobe from time to time. Check the Photoshop splashscreen. Oh, and yeah, he's primary author of Camera Raw...kinda nice to have the author answering your questions, huh?
                      • 8. Re: ACR 4.1 compression when converting to .jpg
                        Thomas Knoll Level 2
                        steve: Did you try the experiment that I suggested?
                        • 9. Re: ACR 4.1 compression when converting to .jpg
                          Level 1
                          Thomas,
                          I've done the suggestion using a .psd instead of a .tiff. There are quality differences, as I would expect.

                          I just didn't expect the differences in the .jpgs produced in previous versions of ACR.

                          Guess it's just my issue.
                          • 10. Re: ACR 4.1 compression when converting to .jpg
                            Ramón G Castañeda Level 4
                            Sorry about the mangling of the Knoll last name. I edited because I had unintentionally typed a lower-case k, and I have no idea how I hit the X key during the editing. My bad, my apologies.

                            I have typed Knoll correctly hundreds if not thousands of time. Just as I have typed Schewe correctly dozens of times, and Jeff caught the one time I mistyped his last name on another forum.

                            • 11. Re: ACR 4.1 compression when converting to .jpg
                              Thomas Knoll Level 2
                              The size differences in JPEGs saved from Camera Raw 4.1 (compared to 4.0) are ONLY a result of 4.1 producing lower noise images, which are easier to compress than 4.0. There as been NO CHANGE whatsoever in the JPEG compression algorithms.
                              • 12. Re: ACR 4.1 compression when converting to .jpg
                                Level 1
                                Thomas,
                                Thank you, that's an explanation that makes sense.
                                By the way, I particularly enjoy the new features such as vibrance, recovery and the other options in 4.1
                                Steve
                                • 13. Re: ACR 4.1 compression when converting to .jpg
                                  Level 1
                                  Steve, your thread which brought up to subject of file size versus detail, be it due to noise or sharpness, for any given compression ratio gave me an idea.

                                  I grabbed an old 1D Mark II N ISO 1600 college basketball image from last season. Using the current DPP set at sharpness 4 I saved the CR2 as a JPG 10, Canon's highest quality. Then using DPP's excellent chrominance noise reduction tool on high to lesson color noise I saved it again.

                                  Next I opened the file in CR4.0 (no 4.1 for me but that's a different thread!) I set the sharpness at 50 which is kinda/sorta/probably about as aggressive as DPP's sharpness 4. I saved JPG 12s with color noise at zero and then at 15, a level that I typically use for ISO 1600. I almost never use any luminance reduction in ACR

                                  The size of the JPG with no DPP noise reduction is 8,293KB. The same image with color noise reduction is only 7,690KB.

                                  The size of Adobe's JPG without color noise reduction is 6,915KB while the color noise reduced version is 5,465. No pixel peeping charts here but my suspicion is that Adobe saves a better quality file in less space than Canon does.
                                  • 14. Re: ACR 4.1 compression when converting to .jpg
                                    Level 1
                                    Jack,
                                    Your test makes a lot of sense to me. I must say though that the Canon file holds up pretty well for image quality.