[Xiaomi Poco X3 NFC Themes, Apps, and Mods] raulbe:
Hi All, wanted to share my findings with the community. These are purely my personal preferences and opinions. I also have an iPhone XR and use that as a baseline.

First I am mainly interested in skin tones, I personally feel we are all very attuned to skin tones and that's the best way to get a feel for a camera's quality.

For things like plants, flowers, landscapes, buildings and objects sometimes it becomes very difficult to tell even poor and good cameras apart.

So lets begin. All this is on MIUI stock 12.0.3 ROM. I will focus on the main and selfie camera. Haven't tested video or the wide lens.

The Stock Camera

The stock camera is decent but has a reddish brownish skin tone. On zoom in many situations you will see smudging. Its also not sharp. The selfie camera suffers from the same problems only more accentuated. Very smudgy, too much contrast, reddish brownish tone and overall lack of clarity and detail. In low light the problems become more accentuated.

Nikita 7.4 2.0 with Vanpoko's config V3

Thanks to vanpoko for coming out with various configs for this. This camera is really extraordinary sharp on objects and color is also decent for objects. However its way too sharp for human subjects and gives an unnatural look. Skins tone also look unnatural. The selfie camera is oversharpened and unnatural - its unusable. The sharpening is extreme and skin tones just look off.

The next 2 are from the Poco X3 camera thread on 4pda. There are more than 650 pages on that thread and I used Google translate to read some of them. There are a lot of configs, versions, differing opinions, samples to wade through.

BSG 8.1 GVq

This one is quite good out of the box. If you have a pet you will get fantastic pictures out of the box with BSG with proper color, detail, sharpness and proper definition on the eyes. Its way way better than stock and in some cases beats my iPhone XR for pets. The colors are on point though some may find it a bit faded. Skin tones are well represented in both good light and low light situations. There is details and none of the smudging you see on the stock. The selfie camera is also good for skin tones, again some may find this slightly washed out but the details are well captured. A simply brightening and contrast in the default image editor will dramatically improve the image for most tastes.

This camera is extremely good for pets. This is on out of the box config. For main lens in the settings I used Pixel4 for both HDR+ and AWB correction. These settings are in settings -> additional modules settings -> settings back lens. For selfie camera I found Samsung T2 AWB gave the best colors. This is in settings -> additional modules settings -> settings front lens -> awb correction. For the custom library I used Lib r1_01_Final - the skin tone colors are slightly better here than the default Google lib. There are many other BSG versions on the 4pda thread but I found the GVq versions shared there worked well. Its available on celsoazevedo Gcam site. Its the 8.1.101_A9_GVq one.

Aspen 8.1.200 and 8.1.011.194

There is not much discussion on this Gcam mod on XDA or on celsoazevedo. Both along with BSG are highly rated on the 4pda thread. I found 8.1.200 nearly as good as BSG, just a slightly different color tone. Its also nearly as sharp as BSG. For the Selfie camera, some may find this better than BSG. Unfortunately the apks and configs are only available in the 4pda thread. The best library I found for color accuracy was 1.8re which many on the thread recommend. Like BSG the Aspen 1.8.200 is much better for skin tones, pets and many other things than the stock cameras.

The 8.1.011.194 version is extremely similar to the 8.1.200 version. Its slightly less sharp I found for pets and skin tones, and the selfie is just slightly, very slightly more natural looking. Again this is with lib1.8re. The other popular lib is 1.9final and I found 1.8re is generally better for skin tones on the front camera. The main camera is quite similar. On Aspen default AWB on gives a cooler more 'pastely' color tone but you can put it off to get a slightly warmer more accurate tone closer to BSG.

The 4pda thread is very confusing but for Aspen the bulk of the posts, configs and apks is shared by user Paradisoko. There are also a lot of useful posts and real world comparisons by both paradisoko and hulksvs on Aspen 8.1 and BSG. Thanks to both of these users and the 4pda community for providing a mod that improves the Poco default camera. One thing to note is Aspen does not support the wide camera while BSG does. I haven't tested much video but BSG records 1080p stabilized.

I think most users will find BSG 8.1 a good alternative to the stock cam. It works well out of the box for the X3 and I personally think colors are extremely accurate and skin tone and details is perhaps as good as the camera hardware allows. Aspen 8.1.200 is also worth trying, its very good, and you can install and use both together. Hope this was useful to users here.