动态范围与亮度Dynamic range & luminance

难度LEVELL1 · 入门L1 · Beginner 领域TOPIC调色

学习目标LEARNING OBJECTIVES

学完你能分清「对比范围」和「显示亮度」两件事，知道 HDR 的门槛在哪、天花板由谁决定。

概念说明CONCEPTS

最暗到最亮能差多少，是对比范围；实际显示有多亮，用 nits 度量。

  • SDR ≈100 nits——传统标准，按约 100 nits 做基准
  • 当前电视 ≈300 nits——消费级显示，比标准亮，但还谈不上 HDR
  • HDR——更高亮 + 更深的暗部：高光和阴影都留得住，需要全链路支持
SDR / HLG / PQ 的传递函数曲线

SDR 顶到 100 nits，HDR 能到上千。天花板由前期决定，后期只能往下调。（曲线按 BT.1886 / BT.2100）

五个方向合起来看：▶ 五维图交互演示（按 1/2/3/4 切换四种素材）。

操作步骤STEPS

  1. 看高光是否死白
  2. 看暗部是否糊成一片
  3. HDR 素材在 SDR 屏上被压平——不是素材坏了

练习PRACTICE

动手任务

拍一段大光比场景（比如窗边逆光），观察死白；再用眼睛直接看同一场景，对比动态范围。

自检清单

做完任务后逐条自查，全部能打勾才算过。 做完任务后逐条自查，全部能打勾才算过。

常见问题FAQ

过曝了，后期拉回来就行？

范围外的信息根本没被记录，拉不回来。

手机说自己能录 HDR，是真的吗？

超过 100 nits 他们就叫它 HDR 了；手机大多到不了真正的 HDR——眼睛的动态范围比手机大。

Learning Objectives学习目标

After this card you can separate two things — contrast range and display brightness — and know where the HDR threshold sits and who sets the ceiling.

Concepts概念说明

How far darkest to brightest can differ is the contrast range; how bright it actually displays is measured in nits.

  • SDR ≈100 nits — the traditional standard, benchmarked at ~100 nits
  • Current TVs ≈300 nits — consumer displays, brighter than the standard, not HDR yet
  • HDR — brighter highlights + deeper shadows: highs and lows both survive; needs the whole chain
Transfer function curves: SDR / HLG / PQ

SDR tops out at 100 nits; HDR reaches into the thousands. The ceiling is set in production; post can only pull it down. (Curves per BT.1886 / BT.2100)

All five axes together: ▶ the five-axis interactive chart (press 1/2/3/4).

Steps操作步骤

  1. Check whether highlights are clipped to white
  2. Check whether shadows turn to mush
  3. HDR footage shown on an SDR screen gets flattened — the footage isn't broken

Practice练习

Hands-on task

Shoot a high-contrast scene (say, backlit by a window), watch the clipping; then look at the same scene with your own eyes and compare dynamic range.

Self-check

Work through the task, then tick every line; all checked means you own this card. Work through the task, then tick every line; all checked means you own this card.

FAQ常见问题

Blown highlights can be pulled back in post, right?

Information beyond the range was never recorded.

My phone says it records HDR — is that real?

Anything above 100 nits gets called HDR; most phones never reach true HDR — your eyes have more dynamic range than your phone.

本卡术语Terms in this card

对比度Contrast 曲线Curves 动态范围Dynamic Range PNGPNG