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What is HDR, anyway?

lux.camera

281–290 of 352 posts

Re: What is HDR, anyway?

#281
post #243

> Our eyes can see both just fine. This gets to a gaming rant of mine: Our natural vision can handle these things because our eyes scan sections of the scene with constant adjustment (light-level, focus) while our brain is compositing it together into what feels like a single moment. However certain effects in games (i.e. "HDR" and Depth of Field) instead reduce the fidelity of the experience. These features limp alo…

HDR, not "HDR", is the biggest leap in gaming visuals made in the last 10 years, I think.

Sure, you need a good HDR-capable display and a native HDR-game (or RTX HDR), but the results are pretty awesome.

Re: What is HDR, anyway?

#282

Earlier quoted context omitted.

Pixel camera hardware or software? Isnt there only one vendor for sensors - Sony?

Samsung also makes sensors for phones. IIRC some Pixels use their sensors.

I think Canon makes at least some of their sensors, and Nikon designs theirs and makes it at a third party I forget the name of that isn't Sony or Samsung but they still do use Sony stuff in a lot of their cameras.

I don't know about Pentax, Panasonic or OMD (formerly Olympus)

Re: What is HDR, anyway?

#283

Earlier quoted context omitted.

Hello indeed! > What is your use case? Retro video games? PC games? Movies? All of the above! The majority of my interest largely stems from the fact that for whatever reason, I am INCREDIBLY sensitive to sample and hold motion blur. Whilst I tolerate it for modern gaming because I largely have no choice, CRT's mean I do not for my retro gaming, which I very much enjoy. (I was very poor growing up, so most of it for…

> Outside of that, we have a "retro" corner in our home with a 32" trinitron. A 32” Trinny. Nice. I have the 32” JVC D-series which I consider my crown jewel. It’s for retro gaming and I have a laserdisc player but a very limited selection of movies. Analog baby. > Sadly though, as I get ready to take on a mortgage, it's likely most of my CRT's will be sold Mortgage = space. You won’t believe the nooks and crannies y…

Speaking of laser disc it's wild how vivid colors are on that platform. My main example movie is Star Trek First contact and everything is very colorful. DVD is muddy. Even a Blu-ray copy kinda looks like crap. A total side note is the surround sound for that movie is absolutely awesome especially the cube battle scene.

Re: What is HDR, anyway?

#284
post #72

I did my PhD in Atomic, Molecular, and Optical (AMO) physics, and despite "optical" being part of that I realized midway that I didn't know enough about how regular cameras worked! It didn't take very long to learn, and it turned out to be extremely important in the work I did during the early days at Waymo and later at Motional. I wanted to pass along this fun video from several years ago that discusses HDR: https:/…

Pixel camera hardware or software? Isnt there only one vendor for sensors - Sony?

He worked mostly on the software side, but of course had important input into what sensors and processors were chosen for the phones.

Re: What is HDR, anyway?

#285
post #262
post #243

> Our eyes can see both just fine. This gets to a gaming rant of mine: Our natural vision can handle these things because our eyes scan sections of the scene with constant adjustment (light-level, focus) while our brain is compositing it together into what feels like a single moment. However certain effects in games (i.e. "HDR" and Depth of Field) instead reduce the fidelity of the experience. These features limp alo…

https://www.realtimerendering.com/blog/thought-for-the-day/ It's crazy that post is 15 years old. Like the OP and this post get at, HDR isn't really a good description of what's happening. HDR often means one or more of at least 3 different things (capture, storage, and presentation). It's just the sticker slapped on advertising. Things like lens flares, motion blur, film grain, and shallow depth of field are mimicki…

> the poster found it via StumbleUpon.

Such a blast from the past, I used to spend so much time just clicking that button!

Re: What is HDR, anyway?

#286
post #268

Earlier quoted context omitted.

> It seems like a mistake to lump HDR capture, HDR formats and HDR display together, these are very different things. These are all related things. When you talk about color, you can be talking about color cameras, color image formats, and color screens, but the concept of color transcends the implementation. > The claim that Ansel Adams used HDR is super likely to cause confusion, and isn’t particularly accurate. Th…

I agree capture, format and display are closely related. But HDR capture and processing specifically developed outside of HDR display devices, and use of HDR displays changes how HDR images are used compared to LDR displays. > The post never said Adams used HDR. I very carefully chose the words Hey I’m sorry for criticizing, but I honestly feel like you’re being slightly misleading here. The sentence “What if I told…

> The sentence “What if I told you that analog photographers captured HDR as far back as 1857?” is explicitly claiming that analog photographers use “HDR” capture,

No, it isn't. It's saying they captured HDR scenes.

> The result of the juxtaposition is that the article did in fact claim Adams used HDR

You can't "use" HDR. It's an adjective, not a noun.

> Film’s 12 stops is not really “high” range by HDR standards, and a little exposure latitude isn’t where “HDR” came from.

The Reinhard tone mapper, a benchmark that regularly appears in research papers, specifically cites Ansel Adams as inspiration.

"A classic photographic task is the mapping of the potentially high dynamic range of real world luminances to the low dynamic range of the photographic print."

https://www-old.cs.utah.edu/docs/techreports/2002/pdf/UUCS-0...

> Perhaps it’s useful to reflect on the fact that HDR has a counterpart called LDR that’s referring to 8 bits/channel RGB.

8-bits per channel does not describe dynamic range. If I attach an HLG transfer function on an 8-bit signal, I have HDR. Furthermore, assuming you actually meant 8-bit sRGB, nobody calls that "LDR." It's SDR.

> Analog cameras have exposure control and thus can capture any range you want.

This sentence makes no sense.

Re: What is HDR, anyway?

#287

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, a…

Use projection mapping, instead of lighting the photo uniformly, use a projector and project a copy of the image onto the photo, thus you get detailed control over how much light the parts of the image receive.

Alternatively, use transparent film and a bright backlight.

Re: What is HDR, anyway?

#288
post #268

Earlier quoted context omitted.

I agree capture, format and display are closely related. But HDR capture and processing specifically developed outside of HDR display devices, and use of HDR displays changes how HDR images are used compared to LDR displays. > The post never said Adams used HDR. I very carefully chose the words Hey I’m sorry for criticizing, but I honestly feel like you’re being slightly misleading here. The sentence “What if I told…

> The sentence “What if I told you that analog photographers captured HDR as far back as 1857?” is explicitly claiming that analog photographers use “HDR” capture, No, it isn't. It's saying they captured HDR scenes. > The result of the juxtaposition is that the article did in fact claim Adams used HDR You can't "use" HDR. It's an adjective, not a noun. > Film’s 12 stops is not really “high” range by HDR standards, an…

Sorry man, you seem really defensive, I didn’t mean to put you on edge. Okay, if you are calling the scenes “HDR” then I’m happy to rescind my critique about Ansel Adams and switch instead to pointing out that “HDR” doesn’t refer to the range of the scene, it refers to the range capability of a digital capture process. I think the point ultimately ends up being the same either way. Hey where is HDR defined as an adjective? Last time I checked, “range” could be a noun, I think… no? You must be right, but FWIW, you used HDR as a noun in your 2nd to last point… oh and in the title of your article too.

Hey it’s great Reinhard was inspired by Adams. I have been too, like a lot of photographers. And I’ve used the Reinhard tone mapper in research papers, I’m quite familiar with it and personally know all three authors of that paper. I’ve even written a paper or maybe two on color spaces with one of them. Anyway, the inspiration doesn’t change the fact that 12 stops isn’t particularly high dynamic range. It’s barely more than SDR. Even the earliest HDR formats had like 20 or 30 stops, in part because the point was to use physical luminance instead of a relative [0..1] range.

8 bit RGB does sort-of in practice describe a dynamic range, as long as the 1 bit difference is approximately the ‘just noticeable difference’ or JND as some researchers call it. This happens to line up with 8 bits being about 8 stops, which is what RGB images have been doing for like 50 years, give or take. While it’s perfectly valid arithmetic to use 8 bits values to represent an arbitrary amount like 200 stops or 0.003 stops, it’d be pretty weird.

Plenty of people have called and continue to call 8 bit images “LDR”, here’s just three of the thousands of uses of “LDR” [1][2][3], and LDR predates usage of SDR by like 15 years maybe? LDR predates sRGB too, I did not actually mean 8 bit sRGB. LDR and SDR are close but not quite the same thing, so feel free to read up on LDR. It’s disappointing you ducked the actual point I was making, which is still there even if you replace LDR with SDR.

What is confusing about the sentence about analog cameras and exposure control? I’m happy to explain it since you didn’t get it. I was referring to how the aperture can be adjusted on an analog camera to make a scene with any dynamic range fit into the ~12 stops of range the film has, or the ~8 stops of range of paper or an old TV. I was just trying to clarify why HDR is an attribute of digital images, and not of scenes.

[1] https://www.easypano.com/showkb_228.html#:~:text=The%20Dynam...

[2] https://www.researchgate.net/figure/shows-digital-photograph...

[3] https://irisldr.github.io/

Re: What is HDR, anyway?

#289

Earlier quoted context omitted.

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 conte…

> but your monitor manages 1000-1500 and only in a small window. Owning a display that can do 1300+ nits sustained across a 100% window has been the biggest display upgrade I think I have ever had. It's given me a tolerance for LCD, a technology I've hated since the death of CRTs and turned me away from OLED. There was a time I would have said i'd never own a non OLED display again. But a capable HDR display changed…

Motion resolution? Do you mean the pixel response time?

CRTs technically have quite a few artifacts in this area, but as content displayed CRTs tend to be built for CRTs this is less of an issue, and in many case even required. The input is expecting specific distortions and effects from scanlines and phosphor, which a "perfect" display wouldn't exhibit...

The aggressive OLED ABL is simply a thermal issue. It can be mitigated with thermal design in smaller devices, and anything that increases efficiency (be it micro lens arrays, stacked "tandem" panels, quantum dots, alternative emitter technology) will lower the thermal load and increase the max full panel brightness.

(LCD with zone dimming would also be able to pull this trick to get even brighter zones, but because the base brightness is high enough it doesn't bother.)

Re: What is HDR, anyway?

#290
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…

If I look at one of the photography books in my shelf, they are even talking about 18 stops and such for some film material, and how this doesn't translate to paper and all the things that can be done to render it visible in print and how things behave at both extreme ends (towards black and white). Read: Tone-mapping (i.e. trimming down a high DR image to a lower DR output media) is really old.

The good thing about digital is that it can deal with color at decent tonal resolutions (if we assume 16 bits, not the limited 14 bit or even less) and in environments where film has technical limitations.

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