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Only the Histogram Tells the Truth - EVO II 6K Exposure Oddity

herein2021

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UPDATE: 13 Oct 2022

Ok, after even more testing I have come to realize that the histogram display when in the air taking an image actually does reflect the color profile being used. I have gotten so used to shooting LOG for video that I am used to exposing using the LOG histogram, but for the uninitiated, this could be problematic since the histogram is showing the compressed LOG profile when in fact the RAW image's histogram is completely different; meaning unless you get used to mentally translating the LOG histogram into an approximation of what the RAW histogram looks like it could be problematic when trying to properly expose RAW images when the LOG color profile or any color profile other than Natural is used.

This to me is an epic failure on Autel's part. The easiest way around this problem in my opinion is to change the color profile to Natural when shooting images and back to LOG when shooting video. The problem of course is that you need to remember to change back and forth and you will waste precious battery life while doing so. I need to do more testing to determine if the RAW histogram and the Natural histogram are mirrors of each other.

ORIGINAL POST

I have gotten used to odd nuances with the EVO II 6K and one thing I've been meaning to write a post about is the strange disconnect between the image that is displayed on the screen and the actual raw file that is produced by the camera. When I first started testing images out of the EVO II 6K I thought Lightroom was not processing the raw image data properly. The on-screen image always appears badly over exposed on my iPad tablet; this in and of itself is no big deal because the displayed image is subject to the tablet's display settings.

What I found really odd though, when looking at the raw images on my editing workstation was that the JPG previews embedded in the raw images also appeared to be over exposed; however, after importing the images into Lightroom they appeared to be properly exposed. I've never given it much thought since I use the histogram to expose my images but today I started really thinking about why there is such a discrepancy between the displayed image, the embedded JPG and the raw file.

What my current theory is, is that the displayed image and the embedded JPG previews in the raw files use the profile that is configured for video. Since I always shoot a LOG profile for video, since the Autel app does not separate the video settings from the photography settings, the LOG profile is applied to the displayed image and the JPG embedded previews as well. This causes the image to look very flat and over exposed. The raw file of course is raw data straight from the camera sensor so it retains the original exposure settings.

I consider this a real oddity since no other camera I have ever shot with does this. Every other camera that I own applies a neutral profile to the embedded JPG image, which means when you preview the raw file on your camera or on your desktop it looks exactly like the raw file will look on import.

The good news is that the histogram when filming either photography or video shows the actual exposure values and the sensor's dynamic range regardless of profile. So this is another case of ignoring the display and even the raw previews and trust the histogram above all else. Below are two comparison images showing the embedded JPG vs the raw file that has been imported into Lightroom. As you can see, the LOG profile has caused the JPG preview image to be very flat and appear over exposed in some areas. The actual image, and the histogram that was displayed on screen when filming is shown in the Lightroom RAW image preview.

I suppose I could fix the display issue by switching the profile to something other than LOG, but I would then have to remember to switch back to LOG for video and for many projects I shoot photos and video without landing first so that would be one more setting that would need to be changed in the air; so I've just gotten used to ignoring the displayed image and trusting the histogram. Of course this leads me to my other pet peeve which is that there is no way to enable a display LUT which would make the whole thing easier to see...but I digress.


JPG Embedded Preview With Histogram (FastStone Image Viewer)
Embedded_JPG.JPG


Actual RAW Image Data With Histogram (Lightroom)
Lightroom-Imported.JPG

Other Potentially Useful Information

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Autel EVO II Pro - User Experience from a DJI User

EXPLORE YOUR WORLD: An Autel EVO II Pro 6K Cinematic Story

Why I ALWAYS use Daylight WB with Drone Cameras
 
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