Setting up your GH5 for HLG HDR capture

We got our GH5 ready for HDR capture in the previous post so how do we make the most of it?

If you have an external recorder or monitor that supports HDR it is easy! Also if you do you probably have a fair bit of money and you are not reading this blog…

Currently Atomos recorders that can be housed all support HDR including HLG

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Nauticam Atomos Flame

The Nauticam Atomos Flame available at list price of $3,650 will house the Shogun Inferno, Shogun Flame, Ninja Inferno and Ninja Flame

On the Atomos website you can see that for the GH5 the products recommended are the Ninja and Shogun Inferno there first is priced at $995 and the second at $1,295.

There is a difference of $300 between the Shogun  and the Ninja  however the Shogun  provides an SDI video port that may turn out quite useful in grading phase. So if you got to the point of spending $3,650 for the housing I would definitely invest the extra $300 needed for the Shogun Inferno.

Once you get a recorder you can set up the GH5 to output 4Kp50/60 at 10 bit and be happy. The HDR screen of the Atomos device will provide the real time monitoring you need to expose footage properly in HLG. It is not my intention to start a debate about log vs HLG there is plenty of material out there.

A very good video is here

If you don’t have a recorder you are left to the GH5 screen that does not support HDR so how are you going to expose correctly? You have a couple of tools available.

The first one is Zebra Patterns that can be accessed in the Monitor subsection of the menu.

There is a great tutorial on YouTube

Now if you are working in HLG you will notice that the maximum value that can be set is 95% this is because luminance in HLG is limited to 64-940.

If you look on ITU website you can see that white ranges between 69 and 87 in HLG so using Zebra we can still attempt at exposing properly without an HDR monitor.

If you do have a reference white balance card you should set the Zebra to 75% as this is the reference for white if you are in the field without a reference your value should be set to max 90% to ensure you don’t blow highlights. Now you will find some website that tell you 95% is fine too but you do want to leave a bit of headroom. If you want you can set Zebra 1 to 75% and Zebra 2 to 95% so you cover all eventualities.

So once you have set the Zebra the next step is to decide if you want to use HLG View Assist or not. Here you have three options:

  1. Off
  2. Mode 1
  3. Mode 2

Off leaves the display in REC709

Mode 1 gives priority to background areas for example the sky

Mode 2 gives priority to the main subject

The 3 modes are really a progression of brightness, when Off the image looks completely desaturated and Log like. In Mode 1 the image appears to have a preference to show shadows in Mode 2 the image looks the brighter and the most punchy making it easy to work on the foreground but crashes the black and shadows quite a bit.

No matter what you select the Zebra value remain unchanged.

The final setting that can be useful is the Waveform monitor which is accessible in the creative video menu. As the Zebra this gives you a real time display of the image within a diagram that on the horizontal axis represent the image left to right and on the vertical has the signal. This is practically a spacial representation of your image and has the same intensity of the Zebra from 0 to 100. So anything too dark on the bottom won’t be visible and things above max will be clipped.

There are several tutorials available on YouTube

So in essence you could try to expose correctly using Zebra and waveform monitors on the GH5 LCD display but let’s face it the screen is tiny and underwater you won’t be really able to use it effectively. If you have an external monitor or recorder this becomes more useful and something to effectively try.

If you are using the camera meter to expose remember that the GH5 as most cameras has only three settings for metering: multi area, center weighted and spot those influence how the camera calculates the average exposure, this is true also if you use manual mode the reading on the meter will change depending on the metering mode. However for what we have said here if your objective is simply not to clip highlights you have a long way to go before reaching 90% IRE with HLG.

In short you have three options to set exposure on your GH5:

1. Super lazy option trust your camera meter as this was a still image, most likely you will be exposing to the right and without further checks there is a chance to have dark area or clipped highlights.

2. Use Zebra and manual exposure in combination with the camera meter to ensure you stay within safe limits.

3. Use waveform monitor and completely ignore the other parameters as this gives you full control of what you are shooting and removes any dependency on having or not an HDR monitor

As a final note it is important to remember that performing a white balance adjustment is essential in order to expose correctly it is not just to get the colour right as the IRE values on what is white actually change and the camera makes assumptions on what is white to calculate the rest. This is especially true for environment in difficult light conditions.

Getting yourself familiar with waveform monitoring is essential for editing as majority of people will not have the possibility to grade on an HDR screen. In the next post I will explain how to get the lowest possible cost HDR screen that supports HLG.

 

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