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What is HDR, anyway?

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791 points _kush | 1 comments | 14 May 25 12:46 UTC | HN request time: 0.208s | source
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dahart ◴[14 May 25 16:48 UTC] No.43986653[source]▶
It seems like a mistake to lump HDR capture, HDR formats and HDR display together, these are very different things. The claim that Ansel Adams used HDR is super likely to cause confusion, and isn’t particularly accurate.

We’ve had HDR formats and HDR capture and edit workflows since long before HDR displays. The big benefit of HDR capture & formats is that your “negative” doesn’t clip super bright colors and doesn’t lose color resolution in super dark color. As a photographer, with HDR you can re-expose the image when you display/print it, where previously that wasn’t possible. Previously when you took a photo, if you over-exposed it or under-exposed it, you were stuck with what you got. Capturing HDR gives the photographer one degree of extra freedom, allowing them to adjust exposure after the fact. Ansel Adams wasn’t using HDR in the same sense we’re talking about, he was just really good at capturing the right exposure for his medium without needing to adjust it later. There is a very valid argument to be made for doing the work up-front to capture what you’re after, but ignoring that for a moment, it is simply not possible to re-expose Adams’ negatives to reveal color detail he didn’t capture. That’s why he’s not using HDR, and why saying he is will only further muddy the water.

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munificent ◴[14 May 25 17:54 UTC] No.43987388[source]▶
> The claim that Ansel Adams used HDR is super likely to cause confusion

That isn't what the article claims. It says:

"Ansel Adams, one of the most revered photographers of the 20th century, was a master at capturing dramatic, high dynamic range scenes."

"Use HDR" (your term) is vague to the point of not meaning much of anything, but the article is clear that Adams was capturing scenes that had a high dynamic range, which is objectively true.

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1. PaulHoule ◴[14 May 25 19:07 UTC] No.43988137[source]▶
I think about the Ansel Adams zone system

https://www.kimhildebrand.com/how-to-use-the-zone-system/

where my interpretation is colored by the experience of making high quality prints and viewing them under different conditions, particularly poor illumination quality but you could also count "small handheld game console", "halftone screened and printed on newsprint" as other degraded conditions. In those cases you might imagine that the eye can only differentiate between 11 tones so even if an image has finer detail it ought to connect well with people if colors were quantized. (I think about concept art from Pokémon Sun and Moon which looked great printed with a thermal printer because it was designed to look great on a cheap screen.)

In my mind, the ideal image would look good quantized to 11 zones but also has interesting detail in texture in 9 of the zones (extreme white and black don't show texture). That's a bit of an oversimplification (maybe a shot outdoors in the snow is going to trend really bright, maybe for artistic reasons you want things to be really dark, ...) but Ansel Adams manually "tone mapped" his images using dodging, burning and similar techniques to make it so.