QN80F is a representative of the Neo QLED series, which means it's a television with Mini LED backlighting. Unlike its cheaper cousin, the QN70F model, here the diodes are placed directly behind the panel (rather than at the edges), which gives a solid advantage in contrast control right from the start. In the 65-inch variant we tested, we counted 88 local dimming zones – a result that may not be particularly impressive, but as it turned out, sufficient to achieve quite decent results.
In tests based on scenes from movies like Oblivion and The Meg, the QN80F performed well – blacks were deep, and the overall image consistency was eye-catching. However, in more demanding moments (e.g., scenes with a lot of bright details on a dark background), a halo effect appeared. This is where the limitation of the number of zones shows – bright elements could bleed into each other, and some details in dark areas lost sharpness and contrast. In one of the helicopter scenes (The Meg), we even noticed a slight flicker in brightness, as if the television was trying its best to maintain visibility of details at the expense of black depth.
However, these are not problems exclusive to this model – the halo effect or contrast drops in very complex scenes are something most Mini LED televisions struggle with, even the more expensive ones. In its class, the QN80F still performs positively and offers clearly better contrast than the QN70F model with edge lighting. For most users, this will be a level more than sufficient – though not ideal.
Samsung M80H is an LCD TV that, according to the manufacturer, uses Mini-LED backlighting. And maybe smaller LEDs placed directly behind the screen are indeed used here, but it's not the same type of Mini-LED we know from more expensive TVs. The M80H lacks local dimming, so the backlight cannot independently control the brightness of individual parts of the image. Black levels are quite decent, mainly thanks to the VA-type panel used. Depending on the scene, our measured contrast was about 5500:1 to over 8000:1. For a TV without local dimming, those are good results, and it's exactly in such designs that VA panels have a considerable advantage over IPS/ADS panels. It's worth noting that part of the results exceed the native contrast of the panel itself, which is about 5000:1. Samsung has implemented a global dimming feature. When there's a lot of black on the screen, the TV dims the entire backlight, making dark areas look deeper. However, this comes at the cost of the brightness of the rest of the image. The M80H therefore won't strongly brighten a small bright spot while maintaining deep black around it; it dims or brightens the whole screen.