Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

What an unprocessed photo looks like

maurycyz.com

Post reply on HN
Print view View original

151–160 of 418 posts

Re: What an unprocessed photo looks like

#151

Post by switchbak »

dheera wrote: post #72
zmgsabst wrote: post #66

Earlier quoted context omitted.

Sure — but people reasonably distinguish between photos and digital art, with “photo” used to denote the intent to accurately convey rather than artistic expression. We’ve had similar debates about art using miniatures and lens distortions versus photos since photography was invented — and digital editing fell on the lens trick and miniature side of the issue.

Journalistic/event photography is about accuracy to reality, almost all other types of photography are not. Portrait photography -- no, people don't look like that in real life with skin flaws edited out Landscape photography -- no, the landscapes don't look like that 99% of the time, the photographer picks the 1% of the time when it looks surreal Staged photography -- no, it didn't really happen Street photography -…

This is a longstanding debate in landscape photography communities - virtually everyone edits, but there’s real debate as to what the line is and what is too much. There does seem to be an idea of being faithful to the original experience, which I subscribe to, but that’s certainly not universal.

Re: What an unprocessed photo looks like

#152

Post by jiggawatts »

AlotOfReading wrote: post #144
jiggawatts wrote: post #80

I've been studying machine learning during the xmas break, and as an exercise I started tinkering around with the raw Bayer data from my Nikon camera, throwing it at various architectures to see what I can squeeze out of the sensor. Something that surprised me is that very little of the computation photography magic that has been developed for mobile phones has been applied to larger DSLRs. Perhaps it's because it's…

This stuff exists and it's fairly well-studied. It's surprisingly hard to find without coming across it in literature though, the universe of image processing is huge . Joint demosaicing, for example, is a decades-old technique [0] fairly common in astrophotography. Commercial photographers simply never cared or asked for it, and so the tools intended for them didn't bother either. You'd find more of it in things lik…

I trawled through much of the research but as you’ve mentioned it seems to be known only in astrophotography and mobile devices or other similarly constrained hardware.

Re: What an unprocessed photo looks like

#153

Post by colmmacc »

0xWTF wrote: post #90

This reminds me of a couple things: == Tim's Vermeer == Specifically Tim's quote "There's also this modern idea that art and technology must never meet - you know, you go to school for technology or you go to school for art, but never for both... And in the Golden Age, they were one and the same person." https://en.wikipedia.org/wiki/Tim%27s_Vermeer https://www.imdb.com/title/tt3089388/quotes/?item=qt2312040 == John…

I've always considered that Tim Jennison quote to be a reference to C.P. Snow's "The Two Cultures" lecture. Steve Jobs' ambition for Apple to be "where the Liberal Arts and Technology meet" also seemed similarly influenced. If you haven't read Snow's lecture, it's well worth the quick read.

Re: What an unprocessed photo looks like

#154

Post by reactordev »

ycombiredd wrote: post #145
zinekeller wrote: post #128

Earlier quoted context omitted.

The NTSC color coefficients are the grandfather of all luminance coefficients. It is necessary that it was precisely defined because of the requirements of backwards-compatible color transmission (YIQ is the common abbreviation for the NTSC color space, I being ~reddish and Q being ~blueish), basically they treated B&W (technically monochrome) pictures like how B&W film and videotubes treated them: great in green, av…

Cool. I could have been clearer in my post; as I understand it actual NTSC circuitry used different coefficients for RGBx and RGBy values, and I didn't take time to look up the official standard. My specific pondering was based on an assumption that neither the ppm2pgm formula nor the parent's "NTSC" formula were exact equivalents to NTSC, and my "ADHD" thoughts wondered about the provenance of how each poster came t…

There are no stupid questions, only stupid answers. It’s questions that help us understand and knowledge is power.

Re: What an unprocessed photo looks like

#157

Post by boltzmann-brain »

shagie wrote: post #101
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…

> 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 the luminance (brightness/detail) data. From the classic file format "ppm" (portable pixel map) the ppm to pgm (portable grayscale map) man page: https://li…

Funnily enough that's not the only mistake he made in that article. His final image is noticeably different from the camera's output image because he rescaled the values in the first step. That's why the dark areas look so crushed, eg around the firewood carrier on the lower left or around the cat, and similarly with highlights, e.g. the specular highlights on the ornaments.

After that, the next most important problem is the fact he operates in the wrong color space, where he's boosting raw RGB channels rather than luminance. That means that some objects appear much too saturated.

So his photo isn't "unprocessed", it's just incorrectly processed.

Re: What an unprocessed photo looks like

#158

Post by jibal »

strogonoff wrote: post #62

An unprocessed photo does not “look”. It is RGGB pixel values that far exceed any display media in dynamic range. Fitting it into the tiny dynamic range of screens by thrusting throwing away data strategically (inventing perceptual the neutral grey point, etc.) is what actually makes sense of them, and what is the creative task.

Right. the statement "Here’s a photo of a Christmas tree, as my camera’s sensor sees it" is incoherent.

Re: What an unprocessed photo looks like

#159

Post by bmitc »

MyOutfitIsVague wrote: post #125
thousand_nights wrote: post #63

Earlier quoted context omitted.

the bayer pattern is one of those things that makes me irrationally angry, in the true sense, based on my ignorance of the subject what's so special about green? oh so just because our eyes are more sensitive to green we should dedicate double the area to green in camera sensors? i mean, probably yes. but still. (⩺_⩹)

Green is in the center of the visible spectrum of light (notice the G in the middle of ROYGBIV), so evolution should theoretically optimize for green light absorption. An interesting article on why plants typically reflect that wavelength and absorb the others: https://en.wikipedia.org/wiki/Purple_Earth_hypothesis

Green is the highest energy light emitted by our sun, from any part of the entire light spectrum, which is why green appears in the middle of the visible spectrum. The visible spectrum basically exists because we "grew up" with a sun that blasts that frequency range more than any other part of the light spectrum.

Re: What an unprocessed photo looks like

#160

Post by beezle »

dheera wrote: post #39
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…

This is also why I absolute hate, hate, hate it when people ask me whether I "edited" a photo or whether a photo is "original", as if trying to explain away nice-looking images as if they are fake. The JPEGs cameras produce are heavily processed, and they are emphatically NOT "original". Taking manual control of that process to produce an alternative JPEG with different curves, mappings, calibrations, is not a crime.

As a mostly amateur photographer, it doesn't bother me if people ask that question. While I understand the point that the camera itself may be making some 'editing' type decision on the data first, a) in theory each camera maker has attempted to calibrate the output to some standard, b) public would expect two photos taken at same time with same model camera should look identical. That differs greatly from what often can happen in "post production" editing - you'll never find two that are identical.
Post reply on HN