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What is HDR, anyway?

(www.lux.camera)
790 points _kush | 2 comments | | HN request time: 0.415s | source
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Terr_ ◴[] No.43990206[source]
> 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 along only while our gaze is aimed at the exact spot the software expects. If you glance anywhere else around the scene, you instead percieve an unrealistically wrong coloration or blur that frustratingly persists no matter how much you squint. These problems will remain until gaze-tracking support becomes standard.

So ultimately these features reduce the realism of the experience. They make it less like being there and more like you're watching a second-hand movie recorded on flawed video-cameras. This distinction is even clearer if you consider cases where "film grain" is added.

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pfranz ◴[] No.43991015[source]
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 mimicking cameras and not what being there is like--but from a narrative perspective we experience a lot of these things through tv and film. Its visual shorthand. Like Star Wars or Battlestar Galactica copying WWII dogfight footage even though it's less like what it would be like if you were there. High FPS television can feel cheap while 24fps can feel premium and "filmic."

Often those limitations are in place so the experience is consistent for everyone. Games will have you set brightness and contrast--I had friends that would crank everything up to avoid jump scares and to clearly see objects intended to be hidden in shadows. Another reason for consistent presentation is for unfair advantages in multiplayer.

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arghwhat ◴[] No.43995744[source]
> Things like lens flares, motion blur, film grain, and shallow depth of field are mimicking cameras and not what being there is like

Ignoring film grain, our vision has all these effects all the same.

Look in front of you and only a single plane will be in focus (and only your fovea produces any sort of legibility). Look towards a bright light and you might get flaring from just your eyes. Stare out the side of a car or train when driving at speed and you'll see motion blur, interrupted only by brief clarity if you intentionally try to follow the motion with your eyes.

Without depth of field simulation, the whole scene is just a flat plane with completely unrealistic clarity, and because it's comparatively small, too much of it is smack center on your fovea. The problem is that these are simulations that do not track your eyes, and make the (mostly valid!) assumption that you're looking, nearby or in front of whatever you're controlling.

Maybe motion blur becomes unneccessary given a high enough resolution and refresh rate, but depth of field either requires actual depth or foveal tracking (which only works for one person). Tasteful application of current techniques is probably better.

> High FPS television can feel cheap while 24fps can feel premium and "filmic."

Ugh. I will never understand the obsession this effect. There is no such thing as a "soap opera effect" as people liek to call it, only a slideshow effect.

The history behind this is purely a series of cost-cutting measures entirely unrelated to the user experience or artistic qualities. 24 fps came to be because audio was slapped onto the film, and was the slowest speed where the audio track was acceptable intelligible, saving costly film paper - the sole priority of the time. Before that, we used to record content at variable frame rates but play it back at 30-40 fps.

We're clinging on to a cost-cutting measure that was a significant compromise from the time of hand cranked film recording.

</fist-shaking rant>

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iamacyborg ◴[] No.43995837[source]
> Look in front of you and only a single plane will be in focus (and only your fovea produces any sort of legibility). Look towards a bright light and you might get flaring from just your eyes. Stare out the side of a car or train when driving at speed and you'll see motion blur, interrupted only by brief clarity if you intentionally try to follow the motion with your eyes.

The problem is the mismatch between what you’re looking at on the screen and what the in-game camera is looking at. If these were synchronised perfectly it wouldn’t be a problem.

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1. arghwhat ◴[] No.43996644[source]
Indeed - I also mentioned that in the paragraph immediately following.
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2. iamacyborg ◴[] No.43997090[source]
Derp