I couldn't resist doing a few, in my opinion, more controlled chart tests on these issues.
Using a test chart designed to detect aliasing, and with the chart the same distance from the camera for all modes, since the optics don't change and therefor the size of the image on the sensor doesn't change with mode, I acquired DNG images, HQ video in Dlog-M, and FOV video in Dlog-M. For reference I shot the same image with a Sony RX100IV with the zoom set to the same as the
M2P. All images were ISO 100 and F4.
The following files are cropped, resampled as explained below, but not processed in any other way, except that the final cropped versions are converted to jpeg (indistinguishable from the DNGs and 16-bit tiff captures from the videos) from a resolution point of view.
Comparison of the
M2P DNG with the RX100 DNG shows similar resolution - not unexpected in terms of sensor properties since they presumably have similar sensors, but it means that the
M2P lens is not too shabby either.
View attachment 48181
M2P DNG
View attachment 48182
RX100 DNG
The slightly angled line pairs are the best indicator of aliasing, and both these images start to show aliasing at about the same line density - level 6. As a sanity check, combining channels and running a line profile on the horizontal line pairs for the DNG produces the following:
View attachment 48185
This clearly shows the loss of contrast at around level 6.
HQ video is a simple crop of the central 4k pixels of the chip, read out fully. It displays similar resolution to the full-chip DNG - expected since it is not sub-sampling - it's fully sampling a portion (3840 x 2160) of the full chip.
View attachment 48183
HQ video, Dlog-M
FOV video is some kind of sub-sampling, and shows some very strange artifacts:
View attachment 48184
FOV video, Dlog-M
Note, in particular, the fact that level 4 shows much more aliasing than levels 5, 6 or 7. That levels 6 and 7 are resolved at all suggests to me that it is not pixel-binning or sub-sampling the sensor sites, but that some kind of spatial filtering is happening on the sensor chip before readout - sort of consistent with some of the comments coming out of DJI on the subject.
For comparison I took the full-sensor DNG and downsampled it to 4k resolution:
View attachment 48186
DNG downsampled to 4k
The result is interesting, but not unexpected relative to the HQ video/DNG. Level 4 is much better relative to the FOV video, while levels 5, 6 and 7 all show more aliasing. So in some ways, DJI's processing of the FOV video brings out more detail, but at the expense of some strange artifacts at intermediate spatial frequencies.
I also shot some real-world images and video and it seems to me that the problems seen in the resolution chart results are really difficult to discern in real video. The DNG still images are competitive with the RX100, which I would count as a significant success.
CAVEATS:
This only presents data from near the center of the field of view, and at ISO 100, F4. Subjectively there was not a significant problem with edge softness, but I haven't done resolution chart tests at the edges. Noise seems well controlled at ISO 100, but I did not test higher-gain settings.