Comment by buildbot | Hacker News Reader

Comment by buildbot | Hacker News Reader

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There is no reason to do this. If you want to apply the algorithms and Iphone uses, simply take a burst and post process later for HDR or whatever. I remember being in middle school and messing around with Hugin and my Minolta bridge camera…

People value quick shots/edits and don’t care about quality or editing things later don’t mind an iPhone doing all this behind the scene - but it is irreversible. The sort of error in the article would drive myself and other photographers up the wall.

Also, an Iphone has a CPU and ISP that outclass desktops from only a few years ago - camera manufacturers simply don’t have the same compute available.

On the other hand, some brands do provide interesting computational photography in their cameras at the very high end. Panasonic mirrorless full frame cameras have a pixel shift mode for super res/no bayer interpolation, with some ability to fix motion between steps. Phase One has frame averaging and dual exposure in their IQ4 digital backs, for sequential capture into a single frame and super high dynamic range respectively.

There is no consumer software that can do what the iPhone does with its sensors.

iPhone HDR produces an HDR image file. Consumer HDR apps do the opposite - they take an HDR raw and tone map an sRGB JPEG out of it.

The only portable format that really supports HDR images is EXR, so if you're not generating that you're not getting it.

(I don't think there's anything that can do deep fusion either, though obviously you need it a lot less.)

Hugin produces exr files from image stacks.

Sure, there’s not a photoshop button, but does github count https://github.com/timothybrooks/hdr-plus

It’s just an algorithm.

Capture One creates .dng files, which are HDR raw equivalents when combining hdr from bracketed RAWs.

> iPhone HDR produces an HDR image file

What file format is this? iPhone produces tone mapped HEIC, yes, but that’s not HDR as you pointed out.

Or do you mean HDR video?

No, the HEIC has a proprietary attachment with the HDR data as well. You can see the iPhone display adapting when you view it in Photos.

Do you have any info on how that attachment is stored/accesssed?

I think I found it:

https://github.com/m13253/heif-hdrgainmap-decode

Thanks! I'll take a look

I don't think that's true. Capture One introduced HDR merging in one of their recent releases [0].

It does raw in "raw" out. You get a DNG out which is demosaiced. I have not yet looked to see what it's doing under the hood, and how the result compares to EXR. (But in my experience, it seems to struggle with large exposure differences, even when on a tripod).

[0]: https://support.captureone.com/hc/en-us/articles/44100147302...

I mean, sure, producing another raw is one way to do it, but I wouldn't really call that an image format.

You are all over this thread trying to prove that iPhones somehow have a unique setup in the industry that no other camera can match, and people keep telling you how wrong you are. DNG is 100% and image format, and can be “raw” or completely processed depending on the layers internally. Educate yourself before making such blanket statements.

I know what a DNG is. It's not a final delivery format; it's not compressed and I don't think eg gaming content pipelines are going to accept it for ingest either.

(Also, macOS won't display them in HDR, but will display EXR files in HDR. Some trivia for you.)

After this comment I get where you’re coming from.

Do you consider the heic files from an iPhone hdr files rather than sdr, even though the extra brightness channel is stored as a separate channel rather than extending the range of rgb values?

-> It's not a final delivery format

linear DNG?

-> it's not compressed

"Lossless and lossy compression (optional): DNG support optional lossless and (since version 1.4) also lossy compression.[36] The lossy compression losses are practically imperceptible in real world images"

-> I don't think eg gaming content pipelines

Why is this a goalpost even??? In what context? Photogrammetry? DNG works just fine.... Or the actual engine itself? found one in 30 seconds of searching: https://github.com/EQMG/Acid

-> macOS won't display them in HDR

Well, that seems like a macOS problem

This is ridiculous at this point.

I actually now agree with them. I think they were simply doing a bad job explaining.

What I think they mean is that the iPhone camera app is the only one that takes an HDR photo of a scene a produces and HDR output image[0] that can be easily shared and viewed IN HDR on multiple devices.

I don't think that EXR is a particularly portable format (do phones even support viewing them in their native photo viewer/manager?) nor one with small file sizes.

The DNGs from Capture One or Lightroom have similar issues, they at least can be viewed on phones, but they do not show up as HDR images.

Other applications, e.g. Hugin, will produce and SDR image. It's based on an HDR image so it captures a wider dynamic range, but it does it through tone mapping back into a SDR image, rather than actually saving and showing the full dynamic range of the HDR image.

[0] I am not convinced that what the iPhone does with their heic images is really HDR, in the sense that the colors still seem to be stored in an SDR range.

I have no idea why you wouldn’t call it an imagine format.

But either way that’s changing the goal posts. Here is a consumer software doing what that iPhone does.

If that’s not to your liking, there is other software which produces 32bit float tiff images, those will support an even higher dynamic without the pain of EXR.

How about JPEG XL?

>camera manufacturers simply don’t have the same compute available.

what forbids them from buying the competitive SoCs from Qualcomm? Pride?

They would have to rewrite entirely their software. There had been some attemps to use these Qualcomm processors in cameras (the Yi M1 for example) and the result was terrible, the autofocus specially.

i think the battery consumption is also quite bad.

Power consumption is the main issue.

Software bloat is another. Current digital cameras start up and are ready to shoot almost instantly.

But it takes a while for a phone to boot up.

Photographers don't want that.

The much larger sensors on a dedicated camera take longer to read out / have physical shutters / are very power hungry, so doing bursts is just a worse tradeoff on a dedicated camera than on a phone.

Also, the camera market is much smaller than the phone market. Also, most camera companies are Japanese and Japanese companies are generally speaking not as good at software as they could be. (Though this is getting less true.)

They don't really even have to do that, they could use the iPhone soc, but the pairing between the phone and the cameras it's not optimal.

Huge amounts of power and data - the power cost of sending 48MP over a PCB vs. over wifi is 12 orders of magnitude. 40pJ Vs . 2.5J !!!!

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