Dreame S100 is a Mini-LED television that in the 65" version uses an IPS/ADS panel. Such a panel does not naturally offer the best contrast on the market, but thanks to a fairly dense Mini-LED backlight, the black levels in this model are quite decent. In less demanding scenes, the contrast could reach values of 30,000:1. This is several times higher and virtually impossible to achieve for any type of LCD panel without local dimming technology. This makes the black levels and contrast in the S100 quite appealing for a less demanding viewer.
Unfortunately, in more demanding shots where a substantial number of small elements appear on a black background, the local dimming algorithms in the Dreame S100 do not work perfectly. The television can become either excessively dark, resulting in super deep blacks, but almost nothing is visible on the screen, or go in the other direction – a large number of details are visible, but the contrast results are very poor. The black levels in very demanding scenes around bright objects take on a grayish hue (halo effect). This is a typical limitation of Mini-LED televisions from the lower and mid-range, and unfortunately, the Dreame S100 is not an exception that handles this problem particularly well. However, it should be noted that generally, the contrast and black levels are definitely better here than in LCD televisions without any local dimming technology.
TCL C7L is a Mini LED TV, which in the 65-inch variant we tested, is equipped with over 1000 local dimming zones. This, combined with a proprietary VA panel (referred to by TCL CSOT as HVA 2.0), delivers really decent results in terms of black levels and contrast. In most of the scenes we measured, black levels and contrast looked really good, and in the easiest shots, the black was deep enough to resemble that known from OLED screens. We are, of course, talking about the least demanding shots with a lot of black on the screen. However, when a larger number of bright elements appear on the screen, and black no longer dominates so strongly, it becomes clear that the TCL C7L – like most Mini LED TVs – has its issues with managing local dimming zones.
This is particularly evident in the standard black bars in movies recorded in the panoramic format 2.35:1. In this case, a clear halo effect, or bright light glow, can appear on the black bars or around small, bright objects. The contrast then drastically drops – from laboratory values of around 200,000:1 to about 10,000:1, which is quite noticeable in a completely dark room. It is worth remembering that this should not be treated as a flaw of the TV but rather as a characteristic of mini-LED technology. Of course, this effect becomes much less bothersome when we turn on at least some soft, diffused light in the room... which I definitely recommend doing during viewing sessions on any LCD TV.