This actually makes alot of sense, and is the missing puzzle-piece in understanding, where this comes from, thank you very much. I already tought of the effect looking like a vignette that is present not evenly, but different depending of the color-channel, and already thought “that would have to be corrected before stitching to be beneficial”, but I did not get, that the auto-calibration already takes care of it. I did not mind to color-correct for this effect in particular, and my last color calibration was on a non-HE-sample, which might explain alot.
This also explains alot xD.
The linked printables-thingy from my wife is indeed using another camera-module, and it is indeed the HQ-Cam, just with a C-/CS-Mount. It is this one and uses a Sony IMX477R as sensor (12MP). In this configuration it has no lens, at all, just the bare sensor, hard to say if it is using lenslets, but I did not noticed any vignetting at all, and this version is intended to be used with external objectives anyways (hence the C-/CS-Mount). There we used a standard-eyepiece-adapter to fit a regular Olympus CH-A Microscope (and - not seen in that printable - with a different-diameter-eyepiece-adapter on an Olympus VM-T stereo-microscope as well, which also works fine, even tough for 3d-objects some halo-ing is to be expected…). This actually worked out of the box. I noticed a somewhat smaller FoV (it looks to me like a higher (narrower) focal-lenght, maybe the eyepiece-adapter is correcting for a different (shorter) length of the optical tube), resulting in a smaller image-circle (at least it seems to me that you have a significant smaller image-circle as with just the eyepiece).
The second noteworthy difference was, that OFM’S color-correction is way off what the picture actually should look like. Flat-field is okay and even, just white-balance (and gain to some degree) is completely off, giving a very teal image most of the time. However, for now I manually color-calibrated the Camera with grey things and noted down the values to be at least be always roughly at the right ballpark (unfortunately I don’t have a translucent grey-card…does something like that even exist? anyways, I digress…). Correcting for WB/Color is however not a big deal anyways, even afterwards in post-processing. As you can see in the Images in that Printables-Thing, The images produced by the cam are at least “okay” out of the Box for different objectives. Those are not post-processed or afterwards color-corrected, just the radiolaria-image was raw-processed (changed to B/W, some basic RAW-processing like sharpening, curves and contrast as well as some maunal “de-dusting” in GIMP for aesthetical reasons).
So beside automatic color- gain- and wb-correction the HQ-cam does work actually fine with all tested RMS-Objectives, some of them HQ-Olympus branded ones (4x,10x,20x,40x), which all produced very useable results. We used the current stable (v2) build on the manual scope. Maybe for “modding purposes” a guideline on how to correct for different camera-models would be helpful, because other than calibration, the HQ-Cam works perfectly fine.