The best factory mode in which we conducted all our tests was "Filmmaker", which has become rather standard in televisions from this manufacturer. However, let's check what its characteristics were before we began the calibration process. The first aspect we will examine is white balance, as despite appearing unassuming, it determines whether the image will be free from any kind of tint. The graph clearly shows that both in SDR and HDR materials, there was a dominant presence of two colours: red and green, which resulted in a strong yellow tint that was ubiquitous across the entire image. This is perfectly visible on the "ColourChecker" palette, where all hues shifted towards their warmer counterparts. The second thing we will scrutinise is, in our opinion, the two most important graphs regarding image quality assessment: gamma and the EOTF curve. Both aim to maintain adequate brightness and contrast. The first one serves to describe the brightness level in SDR materials, while the second shows the rate of luminance increase. Analyzing the first one, we can observe that it was extremely lowered compared to the reference value marked by the orange line. This situation resulted primarily in a sharp increase in brightness and a significant reduction in contrast, almost reminiscent of that in OLED televisions. The EOTF curve exhibited greater "moderation" and only slightly brightened the entire image to 50% of the maximum brightness.
Xiaomi, like many manufacturers, offers a wide range of picture modes. On the S MiniLED, we can find both IMAX Enhanced and Filmmaker. Our tests were conducted in Filmmaker mode, which theoretically aims to reflect a reference image, but the reality turned out to be somewhat different.
Let's start with the test of SDR content. Here, the television had quite a few issues, especially with white balance. The clearly visible dominance of red made the image look too warm, with all colours taking on a reddish hue. This was particularly noticeable in a comparative scene from the film Star Wars. The brightness characteristics (gamma) also left much to be desired – instead of a smooth transition, we had a real "rollercoaster," with a visible excessive brightening of the screen.
In 4K content, the situation improved significantly. The white balance, although still not perfect, was much more balanced, with a slight dominance of red and blue, but without excessive impact on the overall perception. The EOTF curve (responsible for brightness in HDR) showed some brightening in the brightest parts of the image, which was noticeable, for example, in the test scene from the film Pan that we described earlier. These brightening effects may disturb the precision of the image, but in 4K, the overall effect was much more acceptable than in SDR.
Although Xiaomi S MiniLED can pleasantly surprise with 4K content, its factory settings in SDR require solid adjustments, especially regarding white balance and brightness. This is definitely a television that would benefit from calibration.