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.
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:
“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:
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:
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:
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.
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.)