动态范围Dynamic Range

动态范围是画面从最暗到最亮能跨多远——五维体积图上「对比与亮度」那一角。

• SDR：约 100 nits，传统广播与网络视频的旧天花板。
• 电视：约 300 nits，普通 HDR 电视的常见档位。
• HDR：上限更高，暗部与高光同时保有细节。
• 硬切的代价：SDR 世界里高光直接削平、暗部糊成一团——超出范围的信息不是变暗，是没了。

Dynamic range is how far a picture can span from deepest black to brightest highlight — the "contrast & luminance" vertex of the five-axis volume chart.

• SDR: about 100 nits — the old ceiling of broadcast and online video.
• TV: around 300 nits, the common tier of ordinary HDR sets.
• HDR: a higher ceiling; shadows and highlights keep detail at the same time.
• The hard-clip cost: in the SDR world highlights shear flat and shadows mush out — information past the range is not darker, it is gone.