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  • Expose to the right

    I'm not sure if I'm posting in the correct section?

    Given the dynamic range of digital sensors (5 or 6 stops) and the distribution such that each stop records half the light of the previous one, I'm considering the technique 'expose to the right', and correcting in RAW.
    Can't see a tutorial here, but any tips / advice would be welcome
    Steve

    on flickr

  • #2
    Re: Expose to the right

    It is certainly a good technique for maximising DR. It is OK to clip highlights if they are small parts of the image area.

    Always shoooting RAW, I only find it to be necessary to consciously "shoot to the right" in very challenging (dark) situations, in easier circumstances I just use evaluative metering and +0.3 exposure and PP the RAW file in LR5.

    When there is no sky in the frame, I up the exposure correction to +0.7.
    Peter J

    OM-D E-M1 OMD-E-M5ii Various Olympus lenses

    Comment


    • #3
      Re: Expose to the right

      It seems to be accepted wisdom that blown highlights cannot be brought back, but underexposed areas can be brought up to reveal details. By exposing to the right isn't that the same as over exposing? As a relative newbie I ask for clarification.
      Too many cameras!
      E-500, E-510, EPM1, EPL5, EP3, EP5, OM-D E M10, OM-D E M5, Trip 35mm, Samsung WP10 and Panasonic G6 plus lots of lenses many manual focus.

      Photos at http://www.flickr.com/photos/[email protected]/

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      • #4
        Re: Expose to the right

        Originally posted by byegad View Post
        It seems to be accepted wisdom that blown highlights cannot be brought back, but underexposed areas can be brought up to reveal details. By exposing to the right isn't that the same as over exposing? As a relative newbie I ask for clarification.
        No, because even though you are shifting the histogram to the right you still don't want to clip it. This technique works best for preserving shadow detail in poor light with limited dynamic range. It is still useful, however, for scenes with a wide dynamic range where you would adjust the exposure until the histogram just meets the right-hand edge but is not clipped by it. Of course, by doing this you are still sacrificing some of the shadows, but at least it is kept to a minimum. In practice, when shooting raw you can still recover some of the clipped detail in pp providing it is not too extreme.

        Best practice:

        Shoot raw in challenging light.

        Use base ISO (200) if you are able.

        Keep histogram as far to the right as possible without clipping.

        Bracket exposures in 0.3 stops if situation allows, you can choose the best later.

        Consider using graduated ND filters to control dynamic range when shooting landscapes, or HDR or exposure blending from two or more bracketed frames.
        John

        "A hundredth of a second here, a hundredth of a second there � even if you put them end to end, they still only add up to one, two, perhaps three seconds, snatched from eternity." ~ Robert Doisneau

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        • #5
          Re: Expose to the right

          Thanks for that John, very clear and logical once you understand what the term means.
          Too many cameras!
          E-500, E-510, EPM1, EPL5, EP3, EP5, OM-D E M10, OM-D E M5, Trip 35mm, Samsung WP10 and Panasonic G6 plus lots of lenses many manual focus.

          Photos at http://www.flickr.com/photos/[email protected]/

          Comment


          • #6
            Re: Expose to the right

            There is an alternative view of ETTR discussed here:

            http://chromasoft.blogspot.co.uk/200...ain-wrong.html

            Worth a read and the follow-up links at the end of the first article.

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            • #7
              Re: Expose to the right

              That 'chromasoft' article is an interesting read, one I'll have to read again together with the referenced hyperlinks to get a better impression, but for now, the analysis and argument sounds quite logical. ETTR has benefit only when extending the lower ISO limit of the camera, so it says, and there's a colour shift issue when the end-to-end process of capture-to-print, including post processing, is taken into account. Certainly food for thought!
              Steve

              on flickr

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              • #8
                Re: Expose to the right

                The other reason for exposing to the right is that the range of tones is not evenly distributed throughout the exposure range i.e. in the lowest range (EV0-EV1) there are only 8 tonal steps, but 16 in EV1-EV2 and 32 in the next and doubles up until you end up with 256 tones between EV5 and EV6 - those tones closest to the right therefore have more tonal graduation than those at the other end.
                Thus mid tones being registered further towards the right will also benefit from better tonal graduation. This might not be absolutely correct regarding my EV numbers but the principle is correct.......please feel free to correct/elaborate anyone...
                see my blog... http://www.rps.org/my-rps/portfolio
                and flickr page...http://www.flickr.com/photos/brianvickers/

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                • #9
                  Re: Expose to the right

                  That's my understanding as well, and from an arithmetic point of view it would encourage the use of the light sensors accordingly, but the counter argument from cromasoft, which to be fair is basically empirical, would make you stop and think.
                  Steve

                  on flickr

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                  • #10
                    Re: Expose to the right

                    I don't have a systematic way of dealing with difficult lighting I just have the front dial on the E-M1 assigned to exposure compensation and use that constantly according to the subject, mainly just relying on experience sometimes coupled with the histogram but often exposing to the left.

                    David
                    PBase Galleries:-http://www.pbase.com/davidmorisonimages

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                    • #11
                      Re: Expose to the right

                      With raw, as long as you can see both sides of the live histogram you'll be fine. You can correct in PP without losing detail.

                      I tend to shift the histogram towards the right if there's room, and I also have a safety margin set to the histogram warnings, so they show clipping at about 2 and 253, thus giving a small amount of user latitude.
                      Stephen

                      A camera takes a picture. A photographer makes a picture

                      Fuji X system, + Leica and Bronica film

                      My Flickr site

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                      • #12
                        Re: Expose to the right

                        Originally posted by David Morison View Post
                        I don't have a systematic way of dealing with difficult lighting I just have the front dial on the E-M1 assigned to exposure compensation and use that constantly according to the subject, mainly just relying on experience sometimes coupled with the histogram but often exposing to the left.

                        David
                        In the end, this is the best approach. ETTR is just one technique which often works for a particular type of situation, it's not a panacea for every occasion and there are alternative methods for arriving at the same result.

                        I'm most likely to use ETTR when shooting landscapes, particularly when the camera is on a tripod. I'll make an exposure with no compensation then assess the histogram (yes, I chimp and I'm proud of it - it's another tool, like having an instant polaroid). Quite often it will be a satisfactory graph, with no clipping on either side but perhaps some bunching towards the left, tapering off to the right. This indicates that the majority of the pixels, including those that have captured the mid-range tones, are less than ideally exposed. In a way, the histogram is a bit like Depth of Field charts; there isn't an abrupt definition between perfect exposure and clipping at each extremity, more like a gradual fall-off of what is acceptable rather than ideal.

                        In this situation dialing +0.3 compensation may move the histogram a notch to the right, but still without clipping. Try it again and I might get away with +0.7, sometimes even +1. Meanwhile, the greatest mass of pixels, rising to the highest part of the histogram, have shifted more towards the centre, which is where I want the mid-tones to be.

                        However, be careful. In some situations, such as sunlit flowers against a dark background deep in shadow or an illuminated landscape beneath a stormy sky, you may want an exposure represented by bunching, even clipping, on the left. It's important to match the exposure technique to the subject.
                        John

                        "A hundredth of a second here, a hundredth of a second there � even if you put them end to end, they still only add up to one, two, perhaps three seconds, snatched from eternity." ~ Robert Doisneau

                        Comment


                        • #13
                          Re: Expose to the right

                          Originally posted by brianvickers View Post
                          The other reason for exposing to the right is that the range of tones is not evenly distributed throughout the exposure range i.e. in the lowest range (EV0-EV1) there are only 8 tonal steps, but 16 in EV1-EV2 and 32 in the next and doubles up until you end up with 256 tones between EV5 and EV6 - those tones closest to the right therefore have more tonal graduation than those at the other end.
                          Thus mid tones being registered further towards the right will also benefit from better tonal graduation. This might not be absolutely correct regarding my EV numbers but the principle is correct.......please feel free to correct/elaborate anyone...
                          That's also my understanding. To not expose to the right reduces the tonal range of the image, risking posterisation in subsequent PPing.

                          Jim

                          Comment


                          • #14
                            Re: Expose to the right

                            I personally find the blue/orange under/over exposure colouring much easier to use than the live histogram. It's easy to see which parts of the image are blown out and you can then vary the exposure compensation to suit.
                            Paul
                            E-M1ii, Pen-F and too many lenses
                            flickr
                            Portfolio Site
                            Instagram

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                            • #15
                              Re: Expose to the right

                              The article that Invicta linked to is interesting. I remember reading it some time ago and was persuaded of his logic. However, it's worth pointing out that his tests are using some pretty old versions of the raw processors and things may not be the same today. That doesn't necessarily invalidate the conclusion of course.

                              Another problem with ETTR is knowing when you've gone too far right. I find that the Oly cameras will show things as being blown when in fact none of the 3 channels has reached that point. That leads me to allow some overexposure indication (orange blinkies) but not too much. Of course, the blinkies and live histogram are only showing a composite view over all channels so it's possible for one channel to saturate without it being too obvious. This is often a problem with the red channel and it leads to colour shifts (e.g. on flowers).

                              Finally, the Oly sensors are actually pretty good at keeping the noise under control when you push shadows. I remember doing some comparison shots between a 5dii and an E-PL5 when I first got into u43. Pushing one shot with lots of deep shadow, the Oly did significantly better than the Canon which showed lots of noise and banding well before the Oly struggled.

                              For all these reasons, I no longer fret about ETTR and just take as-well-exposed shots as I can.
                              Paul
                              E-M1ii, Pen-F and too many lenses
                              flickr
                              Portfolio Site
                              Instagram

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