“The cinematographer’s job to do good HDR is don’t clip the signal.”
Juan Cabrera, Senior Colorist & Founder at LightBenders
From On the Calculation and Usage of HDR Static Content Metadata by Michael D. Smith and Michael Zink
“A simple histogram analysis shows the distribution of pixel values within an image and can be used to explain some fundamental differences between standard dynamic range (SDR) and HDR imagery. Histograms of the same frame in SDR and HDR formats are shown in Figs. 1 and 2. […] The SDR histogram in Fig. 1 shows a “spike” at the maximum code value, suggesting that clipping of the highlights is occurring, which is quite common in SDR imagery. The “long tail” in the HDR histogram in Fig. 2 suggests that the highlights from the same scene are not clipped in the HDR version.”
According to the authors, not only is clipping of highlights quite common in SDR content, it is also one of the fundamental differences between SDR and HDR imagery. In addition to being unsightly, clipped HDR highlights cannot be recovered in the Dolby Vision derived SDR version. Which is also why exposing for middle gray, as is often done in SDR photography, might not be advisable when working in HDR.
The Daejeon Chronicles 
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