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What is HDR, anyway?

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Re: What is HDR, anyway?

#151

Post by Uncorrelated »

hatsunearu wrote: post #75

Is there any workflow that can output HDR photos (like the real HDR kind, with metadata to tell the display to go into HDR mode) for photos shot with a mirrorless and not an iPhone?

Yes. For example, Lightroom and Camera Raw support HDR editing and export from RAW images, and Adobe published a good rundown on the feature when they introduced it.

https://blog.adobe.com/en/publish/2023/10/10/hdr-explained

Greg Benz Photography maintains a list of software here:

https://gregbenzphotography.com/hdr-display-photo-software/

I'm not sure what FOSS options there are; it's difficult to search for given that "HDR" can mean three or four different things in common usage.

Re: What is HDR, anyway?

#152

Post by ddingus »

mxfh wrote: post #134
sandofsky wrote: post #59

Earlier quoted context omitted.

> Does anyone else find the hubris in the first paragraph writing as off-putting as I do? > "we finally explain what HDR actually means" No. Because it's written for the many casual photographers we've spoken with who are confused and asked for an explainer. > Then spends 2/3rds of the article on a tone mapping expedition, only to not address the elephant in the room, that is the almost complete absence of predictabl…

Maybe my response was part of the broader HDR symptom—that the acronym is overloaded with different meanings depending on where you're coming from. On the HN frontpage, people are likely thinking of one of at least three things: HDR as display tech (hardware) HDR as wide gamut data format (content) HDR as tone mapping (processing) ... So when the first paragraph says we finally explain what HDR actually means , it se…

I took the post about the same way. Thought it excellent because of depth.

Often, we don't get that and this topic, plus my relative ignorance on it, welcomed the post as written.

Re: What is HDR, anyway?

#153

Post by arghwhat »

dahart wrote: 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…

Arguably, even considering HDR a distinct thing is itself weird an inaccurate.

All mediums have a range, and they've never all matched. Sometimes we've tried to calibrate things to match, but anyone watching SDR content for the past many years probably didn't do so on a color-calibrated and brightness calibrated screen - that wouldn't allow you to have a brightness slider.

HDR on monitors is about communicating content brightness and monitor capabilities, but then you have the question of whether to clip the highlights or just map the range when the content is mastered for 4000 nits but your monitor manages 1000-1500 and only in a small window.

Re: What is HDR, anyway?

#154

Post by some-guy »

alerighi wrote: post #98
gwbas1c wrote: post #88

Earlier quoted context omitted.

> I don't own a single 4k or HDR display Don't feel like you have to. I bought a giant fancy TV with it, and even though it's impressive, it's kinda like ultra-hifi-audio. I don't miss it when I watch the same show on one of my older TVs. If you ever do get it, I suggest doing for a TV that you watch with your full attention, and watching TV / movies in the dark. It's not very useful on a TV that you might turn on wh…

I don't either see a point of having 4K TV vs 1080p TV. To me is just marketing, I have at my house both a 4K and a 1080p and from a normal viewing distance (that is 3/4 meters) you don't see differences. Also in my country (Italy) TV transmissions are 1080i at best, a lot are still 570i (PAL resolution). Streaming media can be 4K (if you have enough bandwidth to stream it at that resolution, which I don't have at my…

I agree about 4k vs non-4k. I will say going OLED was a huge upgrade, even for SDR content. HDR content is hit-or-miss...I find some of it is tastefully done but in many cases is overdone.

My own movie collection is mostly 2-4GB SDR 1080p files and looks wonderful.

Re: What is HDR, anyway?

#155

Post by sandofsky »

Diti wrote: post #47
mxfh wrote: post #22

Does anyone else find the hubris in the first paragraph writing as off-putting as I do? "we finally explain what HDR actually means" Then spends 2/3rds of the article on a tone mapping expedition, only to not address the elephant in the room, that is the almost complete absence of predictable color management in consumer-grade digital environments. UIs are hardly ever tested in HDR: I don't want my subtitles to burn…

They also make no mention of transfer functions, which is the main mechanism which explains why the images “burn your eyes” – content creators should use HLG (which has relative luminance) and not PQ (which has absolute luminance) when they create HDR content for the web.

In theory PQ specifies absolute values, but in practice it's treated as relative. Go load some PQ encoded content on an iPhone, adjust your screen brightness, and watch the HDR brightness also change. Beyond the iPhone, it would be ridiculous to render absolute values as-is, given SDR white is supposedly 100-nits; that would be unwatchable in most living rooms.

Bad HDR boils down to poor taste and the failure of platforms to rein it in. You can't fix bad HDR by switching encodings any more than you can fix global warming by switching from Fahrenheit to Celsius.

Re: What is HDR, anyway?

#156

Post by Demiurge »

QuantumGood wrote: post #140
dahart wrote: 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…

Adams adjusted heavily with dodging and burning, even working to invent a new chemical process to provide more control when developing. He was great at determining exposure for his process as well. A key skill was having a vision for what the image would be after adjusting. Adams talked a lot about this as a top priority of his process.

> It's even more incredible that this was done on paper, which has even less dynamic range than computer screens!

I came here to point this out. You have a pretty high dynamic range in the captured medium, and then you can use the tools you have to darken or lighten portions of the photograph when transferring it to paper.

Re: What is HDR, anyway?

#157

Post by munificent »

dahart wrote: 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, which is objectively true.

Re: What is HDR, anyway?

#158

Post by mrandish »

sandofsky wrote: post #59
mxfh wrote: post #22

Does anyone else find the hubris in the first paragraph writing as off-putting as I do? "we finally explain what HDR actually means" Then spends 2/3rds of the article on a tone mapping expedition, only to not address the elephant in the room, that is the almost complete absence of predictable color management in consumer-grade digital environments. UIs are hardly ever tested in HDR: I don't want my subtitles to burn…

> Does anyone else find the hubris in the first paragraph writing as off-putting as I do? > "we finally explain what HDR actually means" No. Because it's written for the many casual photographers we've spoken with who are confused and asked for an explainer. > Then spends 2/3rds of the article on a tone mapping expedition, only to not address the elephant in the room, that is the almost complete absence of predictabl…

> That's because this post is about HDR

It's about HDR from the perspective of still photography, in your app, on iOS, in the context of hand-held mobile devices. The post's title ("What Is HDR, Anyway?"), content level and focus would be appropriate in the context of your company's social media feeds for users of your app - which is probably the audience and context it was written for. However in the much broader context of HN, a highly technical community whose interests in imaging are diverse, the article's content level and narrow focus aren't consistent with the headline title. It seems written at a level appropriate for novice users.

If this post was titled "How does Halide handle HDR, anyway?" or even "How should iOS photo apps handle HDR, anyway?" I'd have no objection about the title's promise not matching the content for the HN audience. When I saw the post's headline I thought "Cool! We really need a good technical deep dive into the mess that is HDR - including tech, specs, standards, formats, content acquisition, distribution and display across content types including stills, video clips and cinematic story-telling and diverse viewing contexts from phones to TVs to cinemas to VR." When I started reading and the article only used photos to illustrate concepts best conveyed with color gradient graphs PLUS photos, I started to feel duped by the title.

(Note: I don't use iOS or your app but the photo comparison of the elderly man near the end of the article confused me. From my perspective (video, cinematography and color grading), the "before" photo looks like a raw capture with flat LUT (or no LUT) applied. Yet the text seemed to imply Halide's feature was 'fixing' some problem with the image. Perhaps I'm misunderstanding since I don't know the tool(s) or workflow but I don't see anything wrong with the original image. It's what you want in a flat capture for later grading.)

Re: What is HDR, anyway?

#159

Post by nfriedly »

Sohcahtoa82 wrote: post #133
nfriedly wrote: post #34

Earlier quoted context omitted.

A lot of monitors that advertise HDR support really shouldn't. Many of them can decode the signal but don't have the hardware to accurately reproduce it, so you just end up with a washed out muddy looking mess where you're better off disabling HDR entirely. As others here have said, OLED monitors are generally excellent at reproducing a HDR signal, especially in a darker space. But they're terrible for productivity w…

I think an OLED is basically an absolute necessity for HDR content. My current monitor is an OLED and HDR in games looks absolutely amazing. My previous was an IPS that supported HDR, but turning it on caused the backlight to crank to the max, destroying black levels and basically defeating the entire purpose of HDR. Local dimming only goes so far.

> My previous was an IPS that supported HDR, but turning it on caused the backlight to crank to the max, destroying black levels and basically defeating the entire purpose of HDR

Yeah, that's kind of what I meant when I said that most monitors that advertise HDR shouldn't.

The AOC monitor is the third or fourth one I've owned that advertised HDR, but the first one that doesn't look like garbage when it's enabled.

I haven't gone oled yet because of both the cost and the risk of burn-in in my use case (lots of coding and other productivity work, occasional gaming).

Re: What is HDR, anyway?

#160

Post by reaperducer »

babypuncher wrote: post #125
reaperducer wrote: post #70

Earlier quoted context omitted.

This is also true for consumers. I don't own a single 4k or HDR display. I probably won't own an HDR display until my TV dies, and I probably won't own a 4k display until I replace my work screen, at which point I'll also replace one of my home screens so I can remote into it without scaling. People in the HN echo chamber over-estimate hardware adoption rates. For example, there are millions of people who went straig…

> A few years ago on HN, there was someone who couldn't wrap their brain around the notion that even though VCRs were invented in the early 1960's that in 1980, not everyone owned one, or if they did, they only had one for the whole family. Point of clarification: While the technology behind the VCR was invented in the '50s and matured in the '60s, consumer-grade video tape systems weren't really a thing until Betama…

Exactly my point. But people on HN, especially the person I referenced, don't understand that we didn't just throw stuff away and go into debt to buy the latest gadgets because we were told to.
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