Update 06/06/2019: We've retested the SDR peak brightness of the C9 with the firmware update 03.60.02. There are no significant changes in brightness from our previous measurements.

The C9 OLED has good peak brightness with SDR content. Small highlights are brighter than on the C8 or B8, but this results in a more aggressive Automatic Brightness Limiter (ABL), which dims the screen significantly when larger areas of the screen get bright.

The C9 has a new Peak Brightness setting, which adjusts how the ABL performs. Setting this to 'Off' results in most scenes being displayed at around 303 cd/m², unless the entire screen is bright, in which case the luminosity drops to around 139 cd/m². Increasing this setting to 'Low', 'Med', or 'High' increases the peak brightness of small highlights. If ABL bothers you, setting the contrast to '80' and setting Peak Brightness to 'Off' essentially disables ABL, but the peak brightness is quite a bit lower (246-258 cd/m² in all scenes).

Unlike most TVs, the C9's peak brightness was measured with the pre-calibration settings, due to an oddity with the 100% window.

These measurements were taken in the 'Expert (Dark Room)' Picture Mode, with OLED Light set to '100', Contrast set to '90', Peak Brightness on 'High'.