10 Replies Latest reply on Nov 29, 2008 5:52 PM by Ramón G Castañeda

    Brightness and Exposure sliders - Noob question

    Level 1
      For 'tone and brigthness' I've been reading that you should always make the first adjustment with the Exposure slider so the images starts to look good(mid tones), not worrying about blown out highlights and to recover them with the highlight tool, is this correct for the way that ACR was written and the way it processes files.

      Also following on from the adjustments to be made from the top down, by default the Brightness slider is at 50 and contrast at 25, should I back these back to O and work from there with the Exposure slider downwards or work from the top down with the defaults as they are?

      I've also read that making the tone adjustments first in the Parametric Curve is better like in PS and then set the Black and White points, which flies in the face of official Adobe advice about working from Exposure first.

      Noobie questions I'm sure but it is a very different way of working from PS and pixels.
        • 1. Re: Brightness and Exposure sliders - Noob question
          Yammer Level 4
          It depends on personal preference, but they designed it so that you can work on the sliders roughly in order. I usually do Exposure first too, but sometimes the image needs something else fixing first, before you can be properly objective about exposure compensation.

          I have no idea why the defaults for Brightness and Contrast are not zero values. I have also no idea what 50 and 25 means. I'd be interested to know too.

          I used to make tone adjustments with the Point Curve, as you had more fine control, but I try to avoid this where possible nowadays unless I can't fix something with basic sliders, graduated filters or post-processing. I may start to use the Parametric Curve more now it can be easily controlled by the Targetted Adjustment Tool.
          • 2. Re: Brightness and Exposure sliders - Noob question
            MadManChan2000 Adobe Employee
            Normally you want some tone mapping to the original raw capture (which is linear data) or the output will look pretty bogus (i.e., flat and lifeless). Brighter midtones and a contrast boost (via an S-curve) are a good way to start tone mapping, and that's what the default brightness & contrast settings do.

            If you are technically inclined and want to get a visualization of exactly what the default CR tone curve looks like, open up the DNG Profile Editor, go to the 2nd tab, and click on the Show Base Tone Curve checkbox.

            Eric

            p.s. If you are photographing extremely low-contrast scenes or happen to be lucky and have a very high dynamic range display, then looking at the original linear data might look ok. These are the exceptions, though, not the rule.
            • 3. Re: Brightness and Exposure sliders - Noob question
              Level 1
              So are you saying that it might be better to adjust the brightness first rather than always start with the exposure slider?

              In PS, I always got the image looking reasonable on screen with the curves dialog before setting the B+W points, as they always seemed to need adjusting after getting the image to look good on screen.

              My understanding was that for general use the defaults would do and then adjust the exposure slider, but to get the most out of the RAW data, to knock every thing back to 0, which would look bad (dark and lifeless) on screen and then start at the top and work your way down, often necessitating a 2-3 stop increase with the exposure slider, bring the highlights under control with the recovery slider, adjust fill and black points and then it would only need a minimal increase with the brightness slider.

              I'm trying to get my head around working with RAW data rather than pixels.

              Cheers

              Ant
              • 4. Re: Brightness and Exposure sliders - Noob question
                MadManChan2000 Adobe Employee
                No, I am not saying that you must start with Brightness. My description and emphasis on the Brightness control was just because of the question asked earlier about why its default is 50 instead of zero.

                Exposure and Brightness are different controls (the main differences being that Exposure is (mostly) linear whereas Brightness is decidedly non-linear, and Exposure shifts the white point while Brightness doesn't). See "Real World Camera Raw" for more details; there are also example workflows in there.

                There are a lot of possible workflows. Some prefer to start with an image looking as good as possible and tweak. Others prefer to start with "linear data" which looks pretty nasty but they have the background and experience to know what to do with it to get the final results they want. (For some, however, a nasty starting point is too strong a psychological disincentive to make any progress. It's true ...)
                • 5. Re: Brightness and Exposure sliders - Noob question
                  Bill_Janes Level 2
                  >I have also no idea what 50 and 25 means. I'd be interested to know too.

                  Thomas Knoll gives the answer to this question in the interview contained in the ACR tutorial presented by Michael Reichman and Jeff Schewe (CR09_BasicPanel.mov). Mr. Knoll stated that the original slider calibration was arbitrarily 0..100. For some controls, the scale was expanded if the original range was insufficient.
                  • 6. Re: Brightness and Exposure sliders - Noob question
                    Level 1
                    Eric

                    Thanks very much for the input, I'll have to check out Real World Camera Raw to see what's what.

                    I suppose that is still the question, 'which to start with' and perhaps the answer is 'it depends'. 'Normal', under or over exposure presumably all have different starting points.

                    I now understand the difference between the two and HOW they work on the data, but still need to work out which is better the starting point, all sliders at 0 or at the ACR defaults of 50/25, if quality is the goal.

                    Thanks and have a good weekend.

                    Ant
                    • 7. Re: Brightness and Exposure sliders - Noob question
                      Robert Shomler Level 4
                      >I'll have to check out Real World Camera Raw to see what's what.

                      The new edition for CS4, includes the ACR 5.2 enhancements, is scheduled to ship in December

                      www.peachpit.com/store/product.aspx?isbn=0321580133&rll=1
                      • 8. Re: Brightness and Exposure sliders - Noob question
                        Ramón G Castañeda Level 4
                        >in the ACR tutorial presented by Michael Reichman and Jeff Schewe (CR09_BasicPanel.mov)

                        I've been meaning to ask if those videos are before of after 5.2. Could you comment on that? It's not clear from the blurb.

                        Thanks in advance.
                        • 9. Re: Brightness and Exposure sliders - Noob question
                          Level 1
                          Camera Raw 4...we're doing a Camera Raw 5 update segment in Dec.
                          • 10. Re: Brightness and Exposure sliders - Noob question
                            Ramón G Castañeda Level 4
                            Thank you, Sir. Most appreciated. :)