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Trying to understand highlight recovery.

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  • Trying to understand highlight recovery.

    Trying to understand how the Highlight recovery slider in ACDSee works.

    When developing a RAW image in develop mode, the overexposed highlights can be recovered to some extent with the “highlights” slider (0-100).
    This works reasonably well.

    My question is does this slider when moved to “100” always provide the same amount of maximum recovery for all RAW images?
    e.g. is it always say 1 stop (or some other stop value) no matter what camera is used?

    or is it like 0%-100% where “100” would be the absolute maximum recovery for a particular camera’s RAW image?

    We know that the maximum amount of highlight recovery that is possible depends, of course, on the camera. Some cameras have more potential highlights recovery “headroom” than others.

    The Olympus OM-D E-M1 mk ii has a particularly high recovery headroom (more than 1.2 stops) . This can be seen from the measurements that DSO publish.

    DSO measure this by comparing the “ISO setting” on the camera and the “measured ISO” value. Please note there is often confusion about what this DSO measurement really means, but the generally accepted view, when experts are looking deeper into that subject, is that this DSO measurement shows how much highlight recovery headroom is available… and the EM1 mk ii has an unusually high amount of headroom available.

    So, the reason I ask is, does the Highlight recovery setting at 100 recover all of the possible highlights in a RAW image from the OM-DE-M1 mk ii ?

    ... or would another raw developer perhaps be able to recover even more ?
    Last edited by Trevor; 06-19-2018, 04:42 AM.

  • #2
    Hi Trevor - Excellent suggestion. I've needed this ability from time to time myself. I will make sure this gets passed along to the Developers.


    • #3
      Originally posted by LV_Bill View Post
      Hi Trevor - Excellent suggestion. I've needed this ability from time to time myself. I will make sure this gets passed along to the Developers.
      Thanks Bill,
      was there any response from the developers to my question ?


      • #4
        Not yet. We'll have to wait and see. Check back in this thread from time to time. /Bill

        Update 6-27-18: Positive reaction to the suggestion. Keep your fingers crossed.
        Last edited by LV_Bill; 06-27-2018, 08:01 AM.


        • #5
          Trevor - Update 7-19-18: I hope you are still watching this thread. Your suggestion is now under serious consideration. Please post a sample image that you feel would benefit from increasing the strength of the Highlight recovery tool. I'll pass it along to the Developers.


          • #6
            That sounds good :-)

            At the moment I can't upload any images here, because of some problem with the forum. I'll post a dropbox link to the raw images instead.

            OK here's that drop box link

            This image is not a masterpiece by any standards it's just a photo of a printed photo taken with the OMD EM1.2
            all shots here were using base ISO 200 and F5.6.
            I just varied the shutter speed (by simply adjusting the Ex compensation in A mode)

            If you look at the sky in the first photo (in develop mode) you can see all the details of the clouds, no highlights are blown it is a bit underexposed.
            If you look at the exif you can see that shutter speed gets slower in each subsequent image and the image gets brighter and in the later images the sky becomes more and more blown out.

            Using ACDSee Ultimate 2018 (build 1309) I can recover the highlights quite well up till image P7210318, it no longer works correctly for the images P7210319, P7210320, P7210321 In all of these the sky looks blotchy even when "highlight recovery " is set to 100 and the "exposure" slider is reduced a bit.

            I estimate this to be about 1 stop or perhaps slightly less of highlight recovery ability using this camera and ACDSee.

            The OMD EM1.2 should have however a bit more "headroom" than this and it should be able to recover perhaps the highlights in image P7210319 properly.

            P7210320 is probably beyond what the OMD EM1 can do, but who knows maybe that is possible too?

            Would be interested if this works.
            Highlight recovery is one of the main reasons I use RAW images.
            Last edited by Trevor; 07-20-2018, 02:49 PM.


            • #7
              I can not solve the problem, but I can confirm I see the same issue.
              (Although admittedly, I typically intentionally under-expose instead of over expose)

              Here is what I did:
              Starting with you photos, I took a look at the +1.7eV image and decreased it by 1.7eV using both ACDSee Ultimate Build 1309. Then compared to the image take at 0eV. Indeed I see the blotches in the sky (and also the conifer trees) in the tweaked/reduced +1.7eV image. The tweak really looks quite bad. Thus, I believe I have confirmed the same results.

              As a double check, I tired the same check using Affinity Photo. Although not perfect, comparing to the 0eV shot, the Affinity image is much better... Minimally, the Affinity version it is not blotchy.


              • #8
                Trevor & Gus - I have sent your information to the Devs. Hopefully, this may generate some support for your request. Be patient, and keep an eye on this thread. /Bill


                • #9
                  Trevor & Gus - Making progress on this request. Stay tuned.