TCL 65C8L (QM8L) HDR brightness dimming issue
I recently picked up the new 65" TCL C8L (QM8L) and I'm running into a frustrating dimming cycle while watching any HDR content.
During an HDR scene with a static bright object (like a brightly lit torch that isn't moving on screen), the TV aggressively dims the brightness after about 1 minute. It stays dim for 2 to 3 minutes, and then returns to full brightness on its own without the scene changing, only to repeat the cycle again.
The most frustrating part is that I specifically chose to buy a Mini-LED instead of an OLED because I didn't want to deal with aggressive panel protection dimming, yet here we are.
My setup:
• Mode: FilmMaker Mode
• Peak Brightness: High
• Local Dimming: High
• Adaptive brightness: off
• Dynamic brightness: off
• Dynamic contrast: off
• All eco settings are completely disabled.
• Firmware: V082.
Has anyone else noticed this specific brightness cycling on the C8L/QM8L? and should i return it?
Edit.
To address the ambient light comment first: the room lighting isn't changing. That’s just my iPhone camera adjusting its exposure when the TV screen aggressively dims.
As for an example, I actually first noticed this while playing Ozark in DV Filmmaker. I couldn't reproduce that exact scene later, but it happened again when I paused a movie and the white player HUD stayed on screen for one minute. The real issue is that when I hit play again, I had to wait 2 to 3 minutes for the brightness to return to normal just so I could continue watching. That long recovery time is what led me to test it with the HDR10 static torch video above.
I tested this exact scenario on my old C835 and my family's C8K, and neither have this issue. I know the old C835 is only 1000 nits, but when the C8L throttles, it drops way darker than the C835. It basically looks like the TV forces the Peak Brightness setting down to "Low," making the picture almost unwatchable in HDR and DV.
Don't get me wrong, I'm not saying it's a bad TV. I actually love it and decided to keep it in hopes of a firmware fix. But TCL really needs to patch this aggressive dimming, or at the very least, shorten that 3-minute recovery time back to normal brightness.