12 Replies Latest reply on Jun 9, 2008 1:44 PM by GeofferyH

    How do the Exposure sliders translate in PS/RAW?

    GeofferyH Level 1
      Does Photoshop's Image>Adjust>Exposure and RAW's Exposure slider translate directly to the camera? That is to say, does a +1.00 in the Exposure dialog equal +1 EV (or stop) on the camera?

      -- I posted this in the Photoshop forum and it was recommended that I post here --

      Geoff
        • 1. Re: How do the Exposure sliders translate in PS/RAW?
          Ramón G Castañeda Level 4
          I wouldn't presume to speak for the luminaries like Thomas Knoll, Eric Chan, Jeff Schewe and many others here, but your question is very straightforward and my understanding is that it can be answered with a simple "Yes".
          • 2. Re: How do the Exposure sliders translate in PS/RAW?
            GeofferyH Level 1
            Thanks for that, good to know.
            • 3. Re: How do the Exposure sliders translate in PS/RAW?
              GeofferyH Level 1
              > I wouldn't presume to speak for the luminaries like Thomas Knoll, Eric Chan, Jeff Schewe and many others here...

              Decent folks indeed.

              I did think it rather remarkable, too, before his passing, when Bruce Fraser would reply to the posts here.
              • 4. Re: How do the Exposure sliders translate in PS/RAW?
                Ramón G Castañeda Level 4
                Bruce Fraser was not only a generous expert always ready to help others, but a true gentleman in that he treated everybody equally, even those of us who didn't particularly deserve it. He is sorely missed.
                • 5. Re: How do the Exposure sliders translate in PS/RAW?
                  Level 1
                  >does a +1.00 in the Exposure dialog equal +1 EV (or stop) on the camera?

                  Yes...and no. Yes, the intent of the Exposure sider is to impact the relative "brightness" (I use the term brightness loosely and not to be confused with the Brightness control) of a camera induced exposure change but no...it really CAN'T do what an actual exposure alteration can do.

                  A digital capture is a linear capture and as such, an underexposure can't really be "fixed" completely by the Camera Raw Exposure slider. While the highlights and midtones can be boosted, an under exposure will result in the loss of shadow detail that will not be completely correctable in Camera Raw. Yes, you can "lighten the shot" but no, it's not exactly the same impact on the image as increasing the camera exposure.

                  Where possible, it's still better to "correctly expose" a digital capture rather than relying on post processing corrections.
                  • 6. Re: How do the Exposure sliders translate in PS/RAW?
                    Ramón G Castañeda Level 4
                    Everything Jeff says is correct, of course.

                    When I replied to the OP, I did so with the understanding that the inquiry was about the response of the increase/decrease of luminance/brightness as shown by the numbers when adjusting the slider, i.e. +1 corresponds to an increase in brightness that would be similar to a one stop in the camera.

                    No one was suggesting that moving the slider would have the same effect as a one stop would have had at the time of the exposure, as if it were possible to go back in time. Such a misconception would be akin to assuming one could recover the missing feet of a person in a shot where the photographer framed the image above the knees by upsampling the image.

                    In that sense, Jeff's clarification is important to avoid a possible though unlikely misunderstanding.
                    • 7. Re: How do the Exposure sliders translate in PS/RAW?
                      Bill_Janes Level 2
                      >A digital capture is a linear capture and as such, an underexposure can't really be "fixed" completely by the Camera Raw Exposure slider. While the highlights and midtones can be boosted, an under exposure will result in the loss of shadow detail that will not be completely correctable in Camera Raw. Yes, you can "lighten the shot" but no, it's not exactly the same impact on the image as increasing the camera exposure.

                      Quite true, but with underexposure even the midtones and highlights will have reduced signal:noise. Improved signal:noise is the main rationale for exposing to the right. The increased number of levels is of lesser or no importance, since these increased levels are largely obscured by noise.

                      http://theory.uchicago.edu/~ejm/pix/20d/tests/noise/noise-p3.html
                      • 8. Re: How do the Exposure sliders translate in PS/RAW?
                        Ramón G Castañeda Level 4
                        Thank you for that link. A most interesting read.
                        • 9. Re: How do the Exposure sliders translate in PS/RAW?
                          MadManChan2000 Adobe Employee
                          A simple way to think about the physical process is that more exposure means more light (i.e., photons) captured. It should be pretty clear that one cannot change this after the fact (i.e., by messing around with sliders such as Exposure in Camera Raw or any other post-processing tool).
                          • 10. Re: How do the Exposure sliders translate in PS/RAW?
                            GeofferyH Level 1
                            > It should be pretty clear that one cannot change this after the fact (i.e., by messing around with sliders such as Exposure in Camera Raw or any other post-processing tool).

                            Yes, I am aware, apologies If I didn't make that clear. I just wanted to clarify as to what the numbers meant really. It is helpful, when making adjustments, to have a point of reference as to what those numbers do mean.
                            • 11. Re: How do the Exposure sliders translate in PS/RAW?
                              Bill_Janes Level 2
                              >Yes, I am aware, apologies If I didn't make that clear. I just wanted to clarify as to what the numbers meant really. It is helpful, when making adjustments, to have a point of reference as to what those numbers do mean.

                              In the future, you might want to check the Photoshop help before posting and avoid aggravation. Here is what it says about the ACR exposure control:

                              Exposure: Adjusts the overall image brightness, with a greater effect in the high values. Decrease Exposure to darken the image; increase Exposure to brighten the image. The values are in increments equivalent to f‑stops. An adjustment of +1.50 is similar to widening the aperture 1‑1/2 stops. Similarly, an adjustment of ‑1.50 is similar to reducing the aperture 1‑1/2 stops.
                              • 12. Re: How do the Exposure sliders translate in PS/RAW?
                                GeofferyH Level 1
                                >Exposure: Adjusts the overall image brightness, with a greater effect in the high values. Decrease Exposure to darken the image; increase Exposure to brighten the image. The values are in increments equivalent to f‑stops. An adjustment of +1.50 is similar to widening the aperture 1‑1/2 stops. Similarly, an adjustment of ‑1.50 is similar to reducing the aperture 1‑1/2 stops.

                                Thanks Bill, I did check the Photoshop help but couldn't find anything about Exposure (at the time). When I did a search for Exposure here is what I got:

                                Adjust Exposure for HDR images
                                Adjust dynamic range view for HDR images
                                Paint on HDR images (Photoshop Extended)
                                Dodge or burn areas
                                Take pictures for use with Photomerge
                                Adjust tone in Camera Raw
                                About the HDR Color Picker (Photoshop Extended)
                                Merge images to HDR
                                Auto blend layers
                                Convert from 32 bits to 8 or 16 bpc
                                About high dynamic range images
                                Preview highlight and shadow clipping in Camera Raw
                                Adjust sharpening in Camera Raw
                                Keys for using the Camera Raw dialog box
                                Apply the Lighting Effects filter
                                Keys for painting objects
                                Display file information in the document window
                                Automatically align image layers
                                Blur filters
                                Create a photomerge interactively
                                White balance controls in Camera Raw
                                Image editing improvements

                                On hindsight, I can now see that it is in Adjust tone in Camera Raw, right there in front of my nose. Thanks for pointing that out.