The three most misunderstood GH4 settings – PART 1: Luminance Levels

Ah, the double-edged sword that is the Internet. A vast repository of information literally at your fingertips in which there’s a decent chance that what you’re reading is dead wrong.

In the case of the Panasonic DMC-GH4K, part of this misinformation stems from the fact that the GH4’s settings often don’t behave as they do on other cameras, especially the Canon cameras favored by so many shooters. The net result is that as users quest to squeeze-out every last ounce of quality – say when trying to create a “flat” image for post processing – they may actually do more damage than good.

I can’t correct every misconception, but over a series of three posts I’m gonna tackle three of the new features that didn’t exist on the GH3 that seem to cause the most confusion: Luminance Levels, Master Pedestal, and Highlights & Shadows.* As I always attempt to do, I’ll rely on samples and my trusty Datacolor SpyderCheckr and SpyderCube to demonstrate rather than only spew my opinion. First up? Luminance levels.

Luminance Levels

0-255, 16-235 or 16-255. What is the correct setting? What setting yields the most dynamic range? And most of all, which setting preserves the fabled “super whites” that will magically fix my over exposed images?

Wow, this one setting causes so much confusion. I’m not going to tackle why these options exist (blame the government and old analog NTSC legal signals) but what I will do is address the misconception that these settings impact the captured dynamic range. The truth is, these setting do not change the actual signal at all. All they do is give hints to your application of choice as to how to display the image. For my examples, I’m going to show how Final Cut Pro X interprets these settings, but the concepts holds true for any NLE. (Although you can expect behavior to vary wildly from app to app.)

First, let’s look at our test image** shot with all three settings:

Luminance: 0-255
Luminance: 16-235
Luminance: 16-255

“Wait a minute, Joe! You said that the images were exactly the same. That last one is clearly blown out. What gives?” you ask? What gives is that FCPX knows how to expect video at the first two ranges, but not the third. Looking at the histograms will explain better than words:

Luminance: 0-255
Luminance: 16-235
Luminance: 16-255

Ah, the fabled unicorn…er, super whites! Let’s adjust them back in line.In other words, let’s tell FCPX where white actually lives:

Luminance: 16-255, corrected
Luminance: 16-255, corrected

That looks remarkably like the first two images doesn’t it? No extra highlight detailed was revealed. The only thing I accomplished was requiring another step in post. Need further proof that there is no extra highlight protection using the 16-235 setting? Let’s reduce the exposure by a stop, after the fact in post:

Luminance: 0-255, -1 stop
Luminance: 16-235, -1 stop

See? The point that white clips remains the same. All we accomplished was making the blown out highlights grey. There is no extra information hiding up there to save your butt when you overexpose.

Take away

  • All settings record the exact same information. One does not give more dynamic range or protection than another.
  • Use the setting that plays nice with your application of choice.
  • That’s most likely going to be 0-255 or 16-235. FCPX doesn’t care. Premiere prefers YUV video to be 16-235 (will save you a step.)
  • 16-255 is an oddball setting that I’ve never heard of any application supporting.

Click here for part 2 where I’ll tackle the ominously named “Master Pedestal” setting.

* If only Panasonic – or any manufacturer – would simply publish detailed information about what each setting actually does, what a wonderful world it would be.

** This image is purposely overexposed, and also features an area of deep shadow (in the closet.)


14 Replies to "The three most misunderstood GH4 settings – PART 1: Luminance Levels"

  • Alison S
    October 29, 2014 (10:14 pm)
    Reply

    Just bought the GH4, planning to shoot a semi tractor-trailer (aerial footage) next week on a closed track. Really need some help getting the settings right. Thanks for your article … going after the others now.

  • joe12south
    October 30, 2014 (7:18 am)
    Reply

    Alison,
    Of course the best thing to do is learn through experimentation, but I can help start you in the right direction. Here’s a very good recipe for a natural, accurate image that doesn’t *require* a ton of post processing, but is still flat enough to provide plenty of room to grade.

    Profile: Natural
    Contrast: -5
    Sharpness: 0
    Noise Reduction: 0
    Saturation: -5
    Hue: +1 (+2 if shooting under LED or fluorescents)
    Shadow: +2
    Highlight: -2
    Master Pedestal: 0

    • Marshall
      October 30, 2014 (12:35 pm)
      Reply

      Why would this be better than Cinelike D? I have been shooting with Cinema D settings since it came out and liking it a lot, however I would love to learn why you prefer this to that?

      • joe12south
        October 30, 2014 (12:47 pm)
        Reply

        I don’t like the way that Cine-D represents color, especially skin tones. Combining Cine-D with flat settings exacerbated the issue. After I got hold of the SpyderCheckr test charts my suspicions seemed confirmed…Cine-D has errors in its color responses in very narrow bands, which are terribly difficult to fix in post. (Very noticeable in reds, oranges and like I said, skin tones.)

        I’m not emphatically stating you shouldn’t use Cine-D…there are some cool plug-ins and LUT’s that require it…but you should at least compare the other profiles. Even “Standard” (dialed down, of course) seems to render color more accurately.

    • Timothy
      December 11, 2015 (8:55 am)
      Reply

      Could you please help with the settings especial for *!* a lot of post? Thank you

  • Alison Shuman
    October 30, 2014 (11:48 am)
    Reply

    Joe – THANK YOU so much for this reply. I will start with these settings. My experience is with Canon (5DII/III), so this is unchartered territory (exhilaration mixed with trepidation!). As we get some time with the GH4, we’ll put up some videos and that can help keep he conversation going.

  • moondragon666
    October 31, 2014 (11:25 am)
    Reply

    Hey Joe I’m going to try the setting you suggested above but do you have any additional thoughts if I want to go straight to post with my files? In other words, flatest image possible for color grading?

    • joe12south
      October 31, 2014 (11:32 am)
      Reply

      If you don’t intend to do much work in post, then you should adjust the contrast, saturation, noise reduction and sharpness to taste. In any case, you really wouldn’t want to take any of them above zero in any normal circumstance. Around -2, -3 seems to yield “normal” results. Definitely something you should experiment with because this is certainly in the realm of “personal preference.”

  • IEBA
    February 26, 2015 (9:37 pm)
    Reply

    Exactly- all three settings record the exact same data coming off the imager.
    The difference is that 0-255 uses more steps to save it.
    Meaning, if you really have to lift something, there’s less chance of banding when you use more of the 8-bits available to you.
    Pre-limiting to 16-235 means you’re not using 36 potential steps in that 256-step 8-bit codec.
    That’s a bad idea.

  • woodybrando
    April 16, 2015 (3:32 am)
    Reply

    yeah I did some tests to try and figure out once and for all if there was a difference between 0-255 and 16-235 settings in the GH4. I shot a light against a white wall so it blew out in the center and was about 50% grey on the edges. And there was noticeably more banding in the 16-235 setting. Have been shooting 0-255 ever since.

  • tobyc
    November 21, 2015 (6:03 am)
    Reply

    Very helpful, thank you!

  • zigazaga
    January 27, 2016 (9:47 pm)
    Reply

    Honestly, why don’t they just have a simple menu and a special advanced one for geeks more interested in rasterbation than photography. The trouble with these interface designers is not only that they’re probably severely mentally ill, they are also unable to understand what a normal person wants from their camera.

    • contentedlife
      October 20, 2016 (3:54 am)
      Reply

      zigazaga – they do make not just a special menu but an entire special mode for people like you – it’s called Auto. Just put your camera on that and don’t bother with any of the settings that so trouble you. For the rest of us, the extent of manual controls available on Panasonic cameras are one of their big selling points.

  • Steve
    December 9, 2016 (3:28 am)
    Reply

    Don’t those settings have to do with broadcast safe colors?


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