Cameras and Lenses (2020)
ciechanow.ski
ciechanow.ski
It's so much fun manipulating things, exploring and getting surprising feedback.
I know it's not really fair to compare this highly scientific masterpiece to the artistic flash websites of the past, but for me at least it immediately evokes the same feelings.
Exporting this site for example in a future proof way is not that obvious. (Exporting as pdf wont work with the webgl applets, exporting the html page might work but is error prone depending in the website structure)
50 years from now, flash emulators will still work on swf files, but these sites might be lost. Or is there a way to archive sites like this?
A couple days ago, someone published their archive of HN that works in any browser.
Archiving sites is easy anyway. I wrote a Scrapy app that archives everything within the a specific fandom on Ao3. TH hardest part is remembering how beautiful soup queries work.
And then hope that whatever browser features you rely on aren't removed in 20 years. Flash applets from 20 years ago are usually more self-contained and Just Work if you have a functioning runtime (either the official one or Ruffle)
https://en.wikipedia.org/wiki/Dynamic_web_page?wprov=sfla1
> A client-side dynamic web page processes the web page using JavaScript running in the browser as it loads.
The linked page is one of those. They're often harder to scrape than server-side rendered webforums and the like.
I'm not sure 50 years from now there will be flash emulators. Who is going to write on for the XP3.12345235 Fruity Ununpentium Silicon x256^2 neuralink devices.
Didn't Flash die because iPhones weren't going to support it? So one of the major OSes people spend most of their lives on can't even run SFW files. Can Android? I've honestly never tried.
But web standards persist.
Edit: Steve from Gamer's Nexus basically agrees: https://www.youtube.com/watch?v=NHO9UtvTPSA
I am always on the lookout for the classic sin of making it look like electromagnetic waves wiggle in space like a snake. I know it's convenient to glue the tangent space to the underlying physical space, but I think it confuses students.
To be clear: the amplitude of the electric and magnetic fields (and hence their components in each direction) oscillate in space/time. Any particular wave though should travel in a straight line (usual caveats apply). Of course you may incidentally also get e.g. sinusoidal variations in intesity perpendicular to the wavevector, but that will be because of the overall beam characteristics.
I don't mean to say I know a better way to show this, and I am aware of many complicating factors. I just think lots of people (my former students and self included) can come away with a wrong idea about how these waves work.
First, light apparently slows down in some materials because the photons are constantly interacting with electrons, and these interactions create secondary waves that are slightly out of phase with the original light. The end result is a modified wave that effectively travels more slowly. So light going in a straight line through air travels more quickly than light going through a lens.
Second, getting more into quantum physics, light typically follows the shortest path from one point to another because that path tends to provide the most constructive interference between different possible routes. (The "why" of this is more involved; Feynman's book QED gives a good intro.)
Third, if you imagine a lifeguard running to rescue someone in the ocean, then they will take the fastest path, which is not directly toward the person in the ocean. Rather, they will run a bit more on the beach in order to have to swim less because travel through the water is slower. The end result is piecewise linear = two straight lines of travel, with a bend at the water line.
To summarize, you can ask "_why_ does light bend going into and out of lenses?" and the answer involves seeing light no longer as a particle but as a wave function (the quantum perspective), and then taking advantage of that wave function's tendency to prefer fastest-travel paths, and then noticing that the apparent bend is in fact the path of fastest travel.
Cameras and Lenses - https://news.ycombinator.com/item?id=25357315 - Dec 2020 (213 comments)
(maybe we already can, I'm simply asking)
Most people who are smart and creative are nowhere near as productive. And most people who are extremely productive don't get sidetracked by side projects.
The way he builds up the mental model from a simple photon bucket to a pinhole and finally to a lens system is just incredible. I particularly loved the section on the circle of confusion. I've read dozens of explanations on depth of field, but being able to interactively drag the aperture slider and see exactly how the cone of light narrows and the blur reduces makes it click in a way that static text never could. This really should be the standard for digital textbooks.
Makes me wish for a similar resource that would teach 3+ element optics, moving elements, and sortof get closer to modern lens design.
Like the other comment says, this can be done with a beam-expanding telescope (which can be as simple as two lenses whose focal length ratios determine the magnification). https://www.newport.com/n/how-to-build-a-beam-expander and https://www.thorlabs.com/an-example-of-a-diy-keplerian-beam-... are a good place to start.
But it can be a bit more complicated than that , and it's often easier to use an LED.
Thanks for sharing it!
To be honest, though, this seems like ideal content for an LLM to produce. It's basically fact regurgitation.
This page wasn’t a regurgitation of facts. It was filled with custom interactive applets that let you explore the effects of physical changes. The core value proposition here is not the facts but the ability to explore and intuit the physics.
I'm not so sure it's that far out of reach, though. From what I've seen the reasoning models do, they're not too far away from being able to run a strategy of figuring out interesting increments of a problem, parameterizing them, making an interactive scene for those parameters, ... it feels within reach.
I personally doubt LLMs are close to producing anything like this, but that wasn’t the point. You indicated that this should be easy for an LLM because it’s just a fact dump. Regardless of whether some future LLM can generate something like this, it’s much more complicated and interesting than a simple fact dump.
You're trolling us, right? "Basically fact regurgitation" is all that teachers do after all. Have you ever noticed the difference between an inspirational teacher and a not-so-inspiring one in terms of effectiveness of communication and the "ah ha!" or lack of moments in your own understanding? If you can honestly say "no", then I might be able to understand your statement above, but really?
Some discussion then: https://news.ycombinator.com/item?id=25357315
I was making the point that the cave painters believed everything including rocks and trees were deeply invested with spiritual power, and they didn't draw a cave painting without investing it with spiritual ideas. Even if one of their goals was to capture an accurate image of some animals, and indicate when in the lunar or solar cycle they were expected to calve, when they went hunting for one a part of the goal would be cut out its heart and eat it raw because of the power contained within, and give thanks to the great mother. Inseparable.
even though I am not spiritual at all, I find your worldview too barren to explain human endeavor.
Nonsense. We don’t know what prehistoric cave painters believed.
> when they went hunting for one a part of the goal would be cut out its heart and eat it raw because of the power contained within
Do you have a pointer to the cave paintings that show hunting animals at certain times in the lunar cycles and eating their hearts raw to harvest this power? Because this sounds made up.
Also this says nothing about art.
you need to study a bit more history, psychology, anthropology, etc., you have absolutely no reason to believe they thought anything different than we do today and what today's hunter gatherers believe. the evidence is on my side. If you have counter evidence, offer it.
>Also this says nothing about art.
I said something about art, whereas till I said it, art was void in the conversation which I think is a glaring mistake which is why I said it. If you have something to say about art, say it, otherwise you don't have a dog in this fight.
People don’t believe this today. What are you talking about? Do you think most people today are hunting animals to eat their raw hearts to gain their power at certain times of the month?
> If you have counter evidence, offer it.
I’m not the one claiming deep insight into the beliefs of prehistoric peoples. Burden of proof is on you.
> I said something about art
You really didn’t. You said nothing meaningful about art except to substitute it for the word picture. And then the rest of your replies have also had nothing to do with art.