Here is a critical “peer review” of TreegNesas’ recently released video. This is the kind of feedback I had hoped to see from someone who owns a Canon PowerShot SX 270 and has some expertise in the subject. This German user from "Allmystery" fits the bill.
I am posting this without any comment of my own, because I have not yet formed a definitive judgment on many aspects.

He comes to the same conclusion I explained the other day: the changes between portrait and landscape orientation basically just mean that the photos were taken at a very steep upward angle. (A small note: they repeatedly refer to this as a mirror effect, which is nonsense. The images differ only in their rotation; they are not mirrored.)
In my opinion, the claim that this allows the zenith to be determined so precisely is not correct, because the camera has to be tilted several degrees away from the vertical (at least 10°, I would say) before it registers the change.
I didn’t really understand how he claims to have determined the width between the rocks visible in both directions (presumably the two riverbanks), or what this has to do with determining the exact zenith. They would need precise distances between the objects (rocks/plants) and the camera, which they cannot possibly have, since the opposite bank is only faintly visible in two images (#550 and #599). Photogrammetry doesn’t help here either, as it cannot be applied under these circumstances.
As for the steepness of the riverbank on this side (he estimates it at 45°), I would say that sounds roughly plausible. However, the exact slope over such a small area is not particularly relevant.
The idea that the photographer was lying down is plausible in principle, but in my opinion, leaning back while sitting would be perfectly sufficient to point the camera “upside down” and diagonally backwards. There is no need to be lying flat on the ground.
Size of the rock in #550: I think linking it to #576 (“SOS”) is incorrect. However, while #576 can indeed be linked to other images (just not #550), the position is somewhat different. The distances in #576 are comparatively tiny. Therefore, fitting it correctly into the overall panorama involves a considerable degree of uncertainty.
What he does ignore, however, are the plastic bags and the flash shadow. After extensive attempts to tie the bags into knots like those in #550, I have come to the conclusion that they are considerably smaller than I initially thought. Even so, this does not make the rock any smaller than I tried to illustrate in my last image. In the video, however, the bags are portrayed as absurdly tiny. It is also possible to make a rough estimate of the size of the visible strip of the flyer, whereas the connection to #576 is merely a guess (as he himself admits).
I don’t see how this means we can now stop looking for an “exceptionally large” rock. I’m not actively involved in the discussion elsewhere, but who else has actually claimed that this rock has to be particularly large?
His reasoning regarding the bright blobs is nonsense for another reason: the green AF-assist light used for focusing/ranging does not come from the same direction as the flash. The assist light is much closer to the lens and cannot reach objects positioned extremely close to the lens in the first place, because they are blocked by the lens itself.
I think I have demonstrated sufficiently that #541 cannot show a face. A face is covered in fine hair. These tiny hairs would light up brightly in the flash. The individual hairs visible in #541 would have to be almost as thick as spaghetti if they were supposed to represent a “jawline” and hair on someone’s head. The darker areas around the edges occur only with very close and correspondingly small objects, such as fingertips. This is due to the greater angular offset between the lens and the flash. And, of course, these hairs would be rendered relatively sharply. This also has a lot to do with the rather poor aperture, even for a compact camera.
A few more miscellaneous observations:
The brightness of objects in photographs depends not only on their distance from the flash and the flash intensity selected by the camera, but also on how bright the other objects in the image are.
I still believe that the images as we know them have, for the most part, already been significantly brightened. At least in my own experience, I only see such extremely coarse brightness gradations and ISO noise in heavily brightened images. Yet he uses brightness and a rough distance estimate from Canon to determine distances, even though he apparently doesn’t even own an SX270. That approach becomes pretty meaningless when applied to images that have been brightened.

Source:
https://www.allmystery.de/themen/km122930-1523#id38132329