Comment by munificent
2 days ago
Yes, Ansel Adams was using a camera to capture a scene that had high dynamic range.
I don't see the confusion here.
2 days ago
Yes, Ansel Adams was using a camera to capture a scene that had high dynamic range.
I don't see the confusion here.
HDR is not referring to the scene’s range, and it doesn’t apply to film. It’s referring superficially but specifically to a digital process that improves on 8 bits/channel RGB images. And one of the original intents behind HDR was to capture pixels in absolute physical measurements like radiance, to enable a variety of post-processing workflows that are not available to film.
"High dynamic range" is a phrase that is much older than tone mapping. I see uses of "dynamic range" going back to the 1920s and "high dynamic range" to the 1940s:
https://books.google.com/ngrams/graph?content=dynamic+range%...
You might argue that "HDR" the abbreviation refers to using tone mapping to approximate rendering high dynamic range imagery on lower dynamic range displays. But even then, the sentence in question doesn't use the abbreviation. It is specifically talking about a dynamic range that is high.
Dynamic range is a property of any signal or quantifiable input, including, say sound pressure hitting our ears or photons hitting an eyeball, film, or sensor.
> But even then, the sentence in question doesn’t use the abbreviation
Yes it does. Why are you still looking at a different sentence than the one I quoted??
HDR in this context isn’t referring to just any dynamic range. If it was, then it would be so vague as to be meaningless.
Tone mapping is closely related to HDR and very often used, but is not necessary and does not define HDR. To me it seems like your argument is straw man. Photographers have never broadly used the term “high dynamic range” as a phrase, nor the acronym “HDR” before it showed up in computer apps like hdrView, Photoshop, and iPhone camera.
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To further complicate the issue, "high dynamic range" is a phrase that will come up across a few different disciplines, not just related to the capture & reproduction of visual data.
The digital process of tonemapping, aka. 'what Apple calls Smart HDR processing of SDR photos to increase perceptual dynamic range', can be applied to images of any number of channels of any bit depth — though, if you want to tonemap a HyperCard dithered black-and-white image, you'll probably have to decompile the dithering as part of creating the gradient map. Neither RGB nor 8-bit are necessary to make tonemapping a valuable step in image processing.
That’s true, and it’s why tonemapping is distinct from HDR. If you follow the link from @xeonmc’s comment and read the comments, the discussion centers on the conflation of tonemapping and HDR.
https://news.ycombinator.com/item?id=43987923
That said, the entire reason that tonemapping is a thing, and the primary focus of the tonemapping literature, is to solve the problem of squeezing images with very wide ranges into narrow display ranges like print and non-HDR displays, and to achieve a natural look that mirrors human perception of wide ranges. Tonemapping might be technically independent of HDR, but they did co-evolve, and that’s part of the history.