A New LUT
This is another post about the highlight rendition on the DJI MAVIC PRO. The first post was published here.
I received a clip from a Eric Jaakkola pointing to the discontinuous tonal gradation in the highlights under specific situations. The transition between sky and direct orange light from the sun puts a lot of stress on these small sensors. Here’s the before and after of a D-LOG (+1:-2;0) Auto WB frame. Eric pointed to that darker yellow halo around the sun. We can also see it shifts towards green, making it a very unpleasing and unrealistic image. The LUT being used here is ICARUS V.2.1 DJI MAVIC PRO D-LOG Sunny WB – sRGB – High Key_64 point.
Here are the RGB values on the original frame. We can see the red and green channels clipping before reaching peak white, leading to a yellow halo around the sun.
ICARUS LUTs deal with this pure yellow not knowing that it sits at the edge of pure white, thus correcting it as was designated to do so with the calibration charts used. This leads to the darker, greenish tone we saw in the first example. There’s the possibility that Auto WB is to blame here. Then again, I wasn’t there when this video was shot, so I don’t know how intense was that orange/yellow sunset shot by Eric.
A less dramatic case
Here is another example, this time shot with sunny white balance. Channel clipping ain’t that dramatic and presents the transition between sky and sun in a more pleasing manner. Notice how the LUT fixes the salmon tinted ring around the yellow area, creating a smoother transition but it can’t insert information where there’s none, just two clipped channels and blue at 38.
Using the corrective LUT
At this point I considered the option of creating a LUT that corrected this artefact. Since recovering clipped channel values is impossible to do with a LUT only, my approach was to clip the yellow color all together while maintaining a pleasing and smooth transition into pure white. Here we see the original D-LOG frame corrected with a LUT that fixed the yellow halo. Beware that this correction will affect the presence of pure yellow (and it’s transition into surrounding colours) anywhere in your image so beware of it’s use.
Using the corrective LUT followed by another ICARUS LUT
Subsequently, any other LUT can be applied. Here we see the original D-LOG clip and a transformed version with the corrective LUT and an ICARUS LUT applied in serial. Notice how the transition is smoothed out even further.
Of course the ideal situation would be to use a precise, dedicated, secondary color correction in your NLE. Here we see the original D-LOG frame and a transformed version with custom made secondaries and an ICARUS LUT applied in serial, plus a custom grade. Everything looks better now, we have an even smoother transition between sky and pure white, no noticeable halos and an overall pleasing, well exposed and vivid image.
Example 2. This is clearly the best of all. The yellow halo was selected, darkened and color was added so it would match the surrounding orange and interior peak white. We get a very smooth transition to peak white and a wider perceived dynamic range. Remember that highlight roll-off is as important as dynamic range.
This corrective LUT is being distributed for free. Download it here
ICARUS Yellow Highlight Channel Clipping Fix
Have you encountered such situations? If so, send me a short clip and I’ll look into your case.
This is where we get really picky about the details, and gladly so.The images we received from all over the world provided a better insight on how the MAVIC sees color and what these LUTs should work with. Thank you to everybody who submitted their media, your participation is essential for the improvement of current and development of new LUTs. As always, you might get better results from a previous version. Existing customers have received this update in the email used to purchase the previous version. Also, if you spot anything out of place while using v.2.1 don’t hesitate in sending me a message. You might see that this or that color looks strange, that a gradation isn’t as smooth as it should or that something simply doesn’t look real. Happy flying everyone!
Release notes for v2.1 – Coming next Monday.
- Blue skies were desaturated and shifted towards green
- Caucasian skintones at the edge of the luminance range were shifted towards yellow and were over saturated. This will affect the hue of sand, rocks, wood and naturally caucasian skin tones.
- Some reds were desaturated and shifted towards magenta
- Two new LUTs added
- ETTR. This LUT was designed for those who expose to the right. Shoot as bright at possible before clipping the highlights. In post, manipulate your exposure, curves, saturation and white balance on your log footage while having this LUT working in a node or adjustment layer ahead/above the clip. Finish the grade with your secondaries and any other adjustments after the LUT.
- ETTR + saturation. The same as before but with a custom curve that increases saturation without clipping or distorting already saturated colours while maintaining neutrals free of chroma noise. It works like the vibrance setting in Adobe Camera Raw but has been molded as illustrated in the curve below.