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What is HDR, anyway?

lux.camera

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Re: What is HDR, anyway?

#181

... something Linux Desktops don't understand and Macs only do well with their own displays with videos. Guess who the winner is on the desktop: Windows oO

Linux does HDR. It's *technically" worked for years but none of the big DEs had it working. Now Ubuntu 25.04 and Fedora 42 (Gnome) have it working out of the box.

ha, interesting. thanks!

Re: What is HDR, anyway?

#182
post #123

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…

[deleted]

Re: What is HDR, anyway?

#183

Note for Firefox users - view the page in Chrome to see more of what they are talking about. I was very confused by some of the images, and it was a world of difference when I tried again in Chrome. Things began to make a lot more sense - is there a flag I am missing in Firefox on the Mac?

https://bugzilla.mozilla.org/show_bug.cgi?id=hdr there's the tracking issue for HDR support.

Tbh, I'm glad this isn't supported in Firefox as of right now

Re: What is HDR, anyway?

#184
post #5

As a photographer, I get the appeal of (this new incarnation of) HDR content, but the practical reality is that the photos I see posted in my feeds go from making my display looking normal to having photos searing my retinas, while other content that was uniform white a second prior now looks dull gray. It's late night here so I was reading this article in dark mode, at a low display brightness - and when I got to th…

While it isn't touched on in the post, I think the issue with feeds is that platforms like Instagram have no interest in moderating HDR. For context: YouTube automatically edits the volume of videos that have an average loudness beyond a certain threshold. I think the solution for HDR is similar penalization based on log luminance or some other reasonable metric. I don't see this happening on Instagram any time soon,…

Btw, YouTube doesn't moderate HDR either. I saw one video of a child's violin recital that was insanely bright, and probably just by accident of using a bad HDR recorder.

Re: What is HDR, anyway?

#185
post #161

Earlier quoted context omitted.

Literally the sentence preceding the one you quoted is “What if I told you that analog photographers captured HDR as far back as 1857?”.

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.

Re: What is HDR, anyway?

#186
post #164
post #162

Earlier quoted context omitted.

And that quote specifically does not "lump HDR capture, HDR formats and HDR display together". It is directly addressing capture .

Correct. I didn’t say that sentence was the source of the conflation, I said it was the source of the Ansel Adams problem. There are other parts that mix together capture, formats, and display. Edit: and btw I am objecting to calling film capture “HDR”, I don’t think that helps define HDR nor reflects accurately on the history of the term.

That’s a strange claim because the first digital HDR capture devices were film scanners (for example the Cineon equipment used by the motion picture industry in the 1990s).

Film provided a higher dynamic range than digital sensors, and professionals wanted to capture that for image editing.

Sure, it wasn’t terribly deep HDR by today’s standards. Cineon used 10 bits per channel with the white point at coding value 685 (and a log color space). That’s still a lot more range and superwhite latitude than you got with standard 8-bpc YUV video.

Re: What is HDR, anyway?

#187
post #123

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…

> 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,…

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.

Re: What is HDR, anyway?

#188

I find the default HDR (as in gain map) presentation of iPhone photos to look rather garish, rendering highlights too bright and distracting from the content of the images. The solution I came up with for my own camera app was to roll off and lower the highlights in the gain map, which results in final images that I find way more pleasing. This seems to be somewhat similar to what Halide is introducing with their "St…

I see that it says it stores images "in an HDR format by default" but keeps referencing JPEG output. Are you using JPEG-XT? There aren't a lot of "before and after" comparisons so it's hard to know how much it's taking out. I figure those would probably hurt the reputation of the app considering its purpose is to un-pop photos, but I'm in the boat of not really being sure whether I do actually like the pop or not. Is…

It's a JPEG + gain map format where the gain map is stored in the metadata. Same thing, as far as I can tell, that Halide is now using. It's what the industry is moving towards; it means that images display well on both SDR and HDR displays. I don't know what JPEG-XT is, aside from what I just skimmed on the Wikipedia page.

Not having before-and-after comparisons is mostly down to my being concerned about whether that would pass App Review; the guidelines indicate that the App Store images are supposed to be screenshots of the app, and I'm already pushing that rule with the example images for filters. I'm not sure a hubristic "here's how much better my photos are than Apple's" image would go over well. Maybe in my next update? I should at least have some comparisons on my website, but I've been bad at keeping that updated.

There's no Live Photo support, though I've been thinking about it. The reason is that my current iPhone 14 Pro Max does not support Live Photos while shooting in 48-megapixel mode; the capture process takes too long. I'd have to come up with a compromise such as only having video up to the moment of capture. That doesn't prevent me from implementing it for other iPhones/cameras/resolutions, but I don't like having features unevenly available.

Re: What is HDR, anyway?

#189
post #186
post #164

Earlier quoted context omitted.

Correct. I didn’t say that sentence was the source of the conflation, I said it was the source of the Ansel Adams problem. There are other parts that mix together capture, formats, and display. Edit: and btw I am objecting to calling film capture “HDR”, I don’t think that helps define HDR nor reflects accurately on the history of the term.

That’s a strange claim because the first digital HDR capture devices were film scanners (for example the Cineon equipment used by the motion picture industry in the 1990s). Film provided a higher dynamic range than digital sensors, and professionals wanted to capture that for image editing. Sure, it wasn’t terribly deep HDR by today’s standards. Cineon used 10 bits per channel with the white point at coding value 685…

They didn’t call that “HDR” at the time, and it wasn’t based on the idea of recording radiance or other absolute physical units.

I’m certain physicists had high range digital cameras before Cineon, and they were working in absolute physical metrics. That would be a stronger example.

You bring up an important point that is completely lost in the HDR discussion: this is about color resolution at least as much as it’s about range, if not moreso. I can use 10 bits for a [0..1] range just as easily as I can use 4 bits to represent quantized values from 0 to 10^9. Talking about the range of a scene captured is leaving out most of the story, and all of the important parts. We’ve had outdoor photography, high quality films, and the ability to control exposure for a long time, and that doesn’t explain what “HDR” is.

Re: What is HDR, anyway?

#190
I have a question: how can I print HDR? Is there any HDR printer + paper + display lighting setup?

My hypothesis are the following:

- Increase display lighting to increase peak white point + use a black ink able to absorb more light (can Vantablack-style pigments be made into ink?) => increase dynamic range of a printable picture

- Alternatively, have the display lighting include visible light + invisible UV light, and have the printed picture include an invisible layer of UV ink that shines white : the pattern printed in invisible UV-ink would be the "gain map" to increase the peak brightness past incident visible light into HDR range.

What do you folks think?

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