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What an unprocessed photo looks like

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Re: What an unprocessed photo looks like

#91

Post by krackers »

Sharlin wrote: post #71
krackers wrote: post #4

>if the linear data is displayed directly, it will appear much darker then it should be. This seems more a limitation of monitors. If you had very large bit depth, couldn't you just display images in linear light without gamma correction.

No. It's about the shape of the curve. Human light intensity perception is not linear. You have to nonlinearize at some point of the pipeline, but yes, typically you should use high-resolution (>=16 bits per channel) linear color in calculations and apply the gamma curve just before display. The fact that traditionally this was not done, and linear operations like blending were applied to nonlinear RGB values, result…

>Human light intensity perception is not linear... You have to nonlinearize at some point of the pipeline

Why exactly? My understanding is that gamma correction is effectively a optimization scheme during encoding to allocate bits in a perceptually uniform way across the dynamic range. But if you just have enough bits to work with and are not concerned with file sizes (and assuming all hardware could support these higher bit depths), then this shouldn't matter? IIRC unlike crts, LCDs don't have a power curve response in terms of the hardware anyway, and emulate the overall 2.2 trc via LUT. So you could certainly get monitors to accept linear input (assuming you manage to crank up the bit depth enough to the point where you're not losing perceptual fidelity), and just do everything in linear light.

In fact if you just encoded the linear values as floats that would probably give you best of both worlds, since floating point is basically log-encoding where density of floats is lower at the higher end of the range.

https://www.scantips.com/lights/gamma2.html (I don't agree with a lot of the claims there, but it has a nice calculator)

Re: What an unprocessed photo looks like

#92

Post by seba_dos1 »

card_zero wrote: post #89
seba_dos1 wrote: post #85

Earlier quoted context omitted.

The article doesn't even go anywhere near what you need to do in order to get an acceptable output. It only shows the absolute basics. If you apply only those to a photo from a phone camera, it will be massively distorted (the effect is smaller, but still present on big cameras).

"Distorted" makes me think of a fisheye effect or something similar. Unsure if that's what you meant.

That's just one kind of distortion you'll see. There will also be bad pixels, lens shading, excessive noise in low light, various electrical differences across rows and temperatures that need to be compensated... Some (most?) sensors will even correct some of these for you already before handing you "raw" data.

Raw formats usually carry "Bayer-filtered linear (well, almost linear) light in device-specific color space", not necessarily "raw unprocessed readings from the sensor array", although some vendors move it slightly more towards the latter than others.

Re: What an unprocessed photo looks like

#93

Post by userbinator »

mgraczyk wrote: post #70
userbinator wrote: post #17

Earlier quoted context omitted.

Everything is an interpretation of the data that the camera has to do What about this? https://news.ycombinator.com/item?id=35107601

I think Samsung was doing what was alleged, but as somebody who was working on state of the art algorithms for camera processing at a competitor while this was happening, this experiment does not prove what is alleged. Gaussian blurring does not remove the information, you can deconvolve and it's possible that Samsung's pre-ML super resolution was essentially the same as inverting a gaussian convolution

If you read the original source article, you'll find this important line:

I downsized it to 170x170 pixels

Re: What an unprocessed photo looks like

#94

Post by MarkusWandel »

But does applying the same transfer function to each pixel (of a given colour anyway) count as "processing"?

What bothers me as an old-school photographer is this. When you really pushed it with film (e.g. overprocess 400ISO B&W film to 1600 ISO and even then maybe underexpose at the enlargement step) you got nasty grain. But that was uniform "noise" all over the picture. Nowadays, noise reduction is impressive, but at the cost of sometimes changing the picture. For example, the IP cameras I have, sometimes when I come home on the bike, part of the wheel is missing, having been deleted by the algorithm as it struggled with the "grainy" asphalt driveway underneath.

Smartphone and dedicated digital still cameras aren't as drastic, but when zoomed in, or in low light, faces have a "painted" kind of look. I'd prefer honest noise, or better yet an adjustable denoising algorithm from "none" (grainy but honest) to what is now the default.

Re: What an unprocessed photo looks like

#95

Post by to11mtm »

seba_dos1 wrote: post #77
to11mtm wrote: post #58

Earlier quoted context omitted.

JPEG with OOC processing is different from JPEG OOPC (out-of-phone-camera) processing. Thank Samsung for forcing the need to differentiate.

I wrote the raw Bayer to JPEG pipeline used by the phone I write this comment on. The choices on how to interpret the data are mine. Can I tweak these afterwards? :)

I mean it depends, does your Bayer-to-JPEG pipeline try to detect things like 'this is a zoomed in picture of the moon' and then do auto-fixup to put a perfect moon image there? That's why there's some need to differentiate between SOOC's now, because Samsung did that.

I know my Sony gear can't call out to AI because the WIFI sucks like every other Sony product and barely works inside my house, but also I know the first ILC manufacturer that tries to put AI right into RAW files is probably the first to leave part of the photography market.

That said I'm a purist to the point where I always offer RAWs for my work [0] and don't do any photoshop/etc. D/A, horizon, bright adjust/crop to taste.

Where phones can possibly do better is the smaller size and true MP structure of a cell phone camera sensor, makes it easier to handle things like motion blur. and rolling shutter.

But, I have yet to see anything that gets closer to an ILC for true quality than the decade+ old pureview cameras on Nokia cameras, probably partially because they often had sensors large enough.

There's only so much computation can do to simulate true physics.

[0] - I've found people -like- that. TBH, it helps that I tend to work cheap or for barter type jobs in that scene, however it winds up being something where I've gotten repeat work because they found me and a 'photoshop person' was cheaper than getting an AIO pro.

Re: What an unprocessed photo looks like

#96

Post by brookst »

barishnamazov wrote: post #7

I love posts that peel back the abstraction layer of "images." It really highlights that modern photography is just signal processing with better marketing. A fun tangent on the "green cast" mentioned in the post: the reason the Bayer pattern is RGGB (50% green) isn't just about color balance, but spatial resolution. The human eye is most sensitive to green light, so that channel effectively carries the majority of t…

Even old school chemical films were the same thing, just different domain.

There is no such thing as “unprocessed” data, at least that we can perceive.

Re: What an unprocessed photo looks like

#97

Post by mgraczyk »

userbinator wrote: post #93
mgraczyk wrote: post #70

Earlier quoted context omitted.

I think Samsung was doing what was alleged, but as somebody who was working on state of the art algorithms for camera processing at a competitor while this was happening, this experiment does not prove what is alleged. Gaussian blurring does not remove the information, you can deconvolve and it's possible that Samsung's pre-ML super resolution was essentially the same as inverting a gaussian convolution

If you read the original source article, you'll find this important line: I downsized it to 170x170 pixels

And? What algorithm was used for downsampling? What was the high frequency content of the downsampled imagine after doing a psuedo inverse with upsampling? How closely does it match the Samsung output?

My point is that there IS an experiment which would show that Samsung is doing some nonstandard processing likely involving replacement. The evidence provided is insufficient to show that

Re: What an unprocessed photo looks like

#98

Post by Dylan16807 »

Sharlin wrote: post #71
krackers wrote: post #4

>if the linear data is displayed directly, it will appear much darker then it should be. This seems more a limitation of monitors. If you had very large bit depth, couldn't you just display images in linear light without gamma correction.

No. It's about the shape of the curve. Human light intensity perception is not linear. You have to nonlinearize at some point of the pipeline, but yes, typically you should use high-resolution (>=16 bits per channel) linear color in calculations and apply the gamma curve just before display. The fact that traditionally this was not done, and linear operations like blending were applied to nonlinear RGB values, result…

The shape of the curve doesn't matter at all. What matters is having a mismatch between the capture curve and the display curve.

If you kept it linear all the way to the output pixels, it would look fine. You only have to go nonlinear because the screen expects nonlinear data. The screen expects this because it saves a few bits, which is nice but far from necessary.

To put it another way, it appears so dark because it isn't being "displayed directly". It's going directly out to the monitor, and the chip inside the monitor is distorting it.

Re: What an unprocessed photo looks like

#99

Post by ksherlock »

disillusioned wrote: post #82
ekidd wrote: post #69

Earlier quoted context omitted.

I have been overusing em dashes and bulleted lists since the actual 80s, I'm sad to say. I spent much of the 90s manually typing "smart" quotes. I have actually been deliberately modifying my long-time writing style and use of punctuation to look less like an LLM. I'm not sure how I feel about this.

Alt + 0151, baby! Or... however you do it on MacOS. But now, likewise, having to bail on emdashes. My last differentiator is that I always close set the emdash—no spaces on either side, whereas ChatGPT typically opens them (AP Style).

On the mac you just type — for an em dash or – for an en dash.

Re: What an unprocessed photo looks like

#100

Post by brookst »

sho_hn wrote: post #54
bstsb wrote: post #42

Earlier quoted context omitted.

hey, not accusing you of anything (bad assumptions don't lead to a conducive conversation) but did you use AI to write or assist with this comment? this is totally out of my own self-interest, no problems with its content

Upon inspection, the author's personal website used em dashes in 2023. I hope this helped with your witch hunt. I'm imagining a sort of Logan's Run-like scifi setup where only people with a documented em dash before November 30, 2022, i.e. D(ash)-day, are left with permission to write.

Phew. I have published work with em dashes, bulleted lists, “not just X, but Y” phrasing, and the use of “certainly”, all from the 90’s. Feel sorry for the kids, but I got mine.
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