The three most misunderstood GH4 settings – PART 2: Master Pedestal
Be careful what you ask for. Adding more “professional” features to a camera means adding features that 99% of users shouldn’t mess with.
In part 1 of this series, I attempted to shed some light on the behavior of the very opaque “Luminance Level” setting. Because of how different applications interpret YUV luminance levels, there’s no cut and dry answer about which setting is best for your workflow. Luckily, the topic of today’s post is much easier to understand.
In short, unless you have some very specific production workflow need that requires you to match black levels (like live broadcast for example) then increasing Master Pedestal above zero accomplishes nothing except for wasting some of the precious few 8 bits you have to encode your image. There are people on the Intarwebs suggesting otherwise, so let me say this very clearly: Increasing the Master Pedestal will NOT increase shadow detail nor will it decrease shadow noise.
Rather than try to explain why this setting exists and why you would want to use it, I’m going to use some examples to show you why you almost certainly don’t want to use it at all.
You may look at the above examples and conclude that increasing the Master Pedestal is a good tool to reveal more shadow detail and maybe even reduce some of that nasty shadow noise, right? Sure looks like it, huh?
Turns out our eyes are notoriously bad at picking out information in shadows (codecs actually rely on this fact.) This is one case where you can’t trust your peepers. We need another way to look at what was actually recorded. Enter the trusty histogram.
See, even at zero, my exposure was such that I wasn’t crushing my blacks. (Remember, I was purposely over-exposing.) By increasing the Master Pedestal, I didn’t increase the amount of shadow information recorded…I actually decreased it. The exact same picture information got crammed into fewer bits (that’s bad, that’s how you get nasty 8-bit artifacts like banding) because a nice hunk of the bottom end was wasted. To put it another way, adjusting the Master Pedestal up increases the compression of the data.
The better tool to reveal shadow detail is the “Highlight and Shadow” setting. In the final entry in this series, I’ll demonstrate exactly what that setting does. If you’re used to working with curves on other cameras or in post, you might be surprised to learn what this setting actually does on the GH4.