The three most misunderstood GH4 settings – PART 3: Highlight & Shadow

Not all curve controls are created equal. I thought I knew what to expect from the GH4 Highlight and Shadow settings. I was wrong.

In part 1 I demonstrated how the “Luminance Level” setting was not a tool for protecting highlights. In part 2 I demonstrated how the “Master Pedestal” setting simply shifts the black level without revealing any more real detail. Now, I’ll end this three parter with other setting that “flat” shooters love to crank-up…

Highlight and Shadow

First, let’s talk about what this setting is not…it’s not a gamma curve. Nope. Really. I promise. Look at the on-screen curve as you adjust highlight and shadow. What stays in place? That’s right, the midpoint. You can’t adjust the midpoint. You can’t directly adjust the gamma. (For the record, a traditional gamma curve would directly adjust nothing but the midpoint.)

So, what do these settings do?* Or what should they do? Let’s start with my expectation.

As a curve adjustment, and based on the graphics the camera displays during adjustment, I expected the settings to leave the absolute black point (0%), midpoint (50%) and white point (100%) the same. In between those points, I expected that the Shadow setting would shift more of the data towards (+ settings) or away (- settings) from the midpoint. Conversely, I expected that the Highlight setting would shift more of the data towards (- settings) or away (- settings) from the midpoint. Additionally, I expected that the total amount of highlight or shadow data would remain the same…just distributed differently relative to the midpoint.

Is that what they do…well, sort of. Let’s go to the tape:

Highlight: 0, Shadow: 0
Highlight: -1, Shadow: +1
Highlight: -4, Shadow: +4
Highlight: 0, Shadow: 0
Highlight: -1, Shadow: +1
Highlight: -4, Shadow: +4

Histogram with all three settings overlaid

So what’s happening here?

What I expected to see, and did:

  1. The 50% midpoint basically stays put.
  2. The 100% white point basically stays put.

What I didn’t expect to see, but did:

  1. The absolute black point is shifted upwards (losing usable data) as the Shadow setting is increased.**
  2. While white point stays consistent, the total quantity of highlight data lowers (not just shifts) as the Highlight setting is lowered.

Take away

  • Highlight and Shadow are the most finessed of the GH4’s luminance controls. It’s the only one that actually increases usable picture information for better post processing.
  • A little bit goes a long way. If your desire is to create a flatter image for post processing, S+1,H-1 or S+2,H+2 is plenty.
  • Be especially careful with the Shadow setting. Increasing it too much will simply pack noisy shadow information into less bits.

* They really are two separate settings, grouped together – they don’t really impact each other. It is convenient to manipulate them as one, though.
** I think this was partly exacerbated by the fact that my image was over exposed, and those didn’t have any true blacks. Even so, looking at the +4 image seems to indicate that the black point is shifting. I need to shoot another test with a properly exposed image to confirm.


8 Replies to "The three most misunderstood GH4 settings – PART 3: Highlight & Shadow"

  • Roman
    January 16, 2015 (11:38 am)
    Reply

    Thanks for the information, very useful!

  • pietz
    January 24, 2015 (9:10 am)
    Reply

    a few months back i did a quick test and noticed that contrast -5 does the exact same thing as Shadows +3 and Highlights -3. as my conclusion S+H adjustments only make sense when:

    1. you wanna adjust S and H separately to different values (everything other than S=-H)
    2. you wanna push it even further than contrast on -5 or +5

    i didnt test this in detail but i think adjusting contrast AND shadows & highlights is probably not the best idea, if none of the rules apply to you. i base this on the fact that chaning the curve with lots of different settings cant make it any better.

  • Ian Baguley
    February 3, 2015 (3:25 pm)
    Reply

    Thank you so much for this article. You explain these settings in a way that makes so much sense. I was really getting concerned about the amount of noise I was getting with certain settings and a few simple video shots here absolutely confirm your findings. Brought down to basics, if you try to squash picture information into a smaller area it’s no different from trying to do the same thing with audio. There will be a price to pay and that price will be detail.

  • jonpais
    March 8, 2015 (1:30 am)
    Reply

    I can’t seem to get the camera to remember the highlight/shadow settings. Once I turn the camera off, the settings return to default. Is there something I’m doing wrong?

    • Spencer
      June 5, 2015 (5:25 pm)
      Reply

      you need to save it under your custom profile. The “movie” setting should always remember, but the custom profiles reset to whatever was saved.

  • Max Taste
    April 14, 2015 (2:30 pm)
    Reply

    Dude, you just rock !

    I love the combination of your professionnal analysis and your friendly writing, you just says it all !
    If you have more to say about the GH4 do not hesitate.

    Bless you

  • asokolsky
    July 12, 2015 (2:29 am)
    Reply

    Thank you! This as well as your recommended GH4 settings (found elsewhere on this site) were very helpful. How about i.Dynamic and i.Resoluton? Any recommendation for post-processing the footage captured with those settings?

    • joe12south
      July 12, 2015 (8:34 am)
      Reply

      Honestly, the first thing I did was make sure these settings were “off” and have never used them. Just like auto-exposure, I avoid any setting that can change the picture automatically, out of my control, mid-clip.


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