Cameras and Lenses (2020)

(ciechanow.ski)

304 points | by sebg 5 hours ago

17 comments

  • scosman 2 hours ago
    If anyone hasn't already seen Bartosz's mechanical watch animations, they are also amazing: https://ciechanow.ski/mechanical-watch/
  • nntwozz 2 hours ago
    Bartosz Ciechanowski's blog brings back the joy of surfing the web during the heyday of Adobe Flash (minus the 100% CPU).

    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.

    • zbendefy 2 hours ago
      Tangential, but Flash had a nice side effect that the "app" could be exported in a self contained way via SWF.

      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?

  • dang 4 hours ago
    One past thread (only?) - others?

    Cameras and Lenses - https://news.ycombinator.com/item?id=25357315 - Dec 2020 (213 comments)

  • Y_Y 4 hours ago
    Amazing as usual.

    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.

    • mal10c 24 minutes ago
      I agree with your thought process. Factoring in antenna type and reflections also causes difficulties when explaining concepts like super position. The sinusoid is a good illustration of what a given receiver might detect at some location (X,Y,Z). A more accurate way to show that may be a light source fading on and off to match some frequency (below THz). Then factoring in the speed of light, at time zero, the light will be off, at some arbitrary time 1, the light will be illuminated at 0.25 (scale goes up to 1 here). The light energy peak at time 1 is at the light. Then at time 2, the light goes up to 0.5. That means that the 0.25 light is now 1 unit away from the light while the 0.5 is at the light. Step to time 3 and the light goes up to 0.75, meaning 1 unit from the light, the light is at 0.5 and 2 units from the light, the light is dimmer at 0.25. This repeats with the light hitting 1.0 then falling back to 0.75, then 0.5, etc. The movement of light is key and I think that's what is often either misunderstood or just not considered enough.
  • stared 3 hours ago
    I am amazed by people like Bartosz Ciechanowski and Andrey Karpathy. What would be a lifetime side project for other smart and curious people, they seem to release every quarter. How do they do it?

    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.

  • fsckboy 2 hours ago
    Cameras and Lenses and photography has been such a fascinating and open and do-it-yourself tinkering medium for well over a century: when are we going to get to be able to play around with what's inside iPhone, Samsung, and Pixel cameras?

    (maybe we already can, I'm simply asking)

  • Fiveplus 5 hours ago
    Every time I come across one of Bartosz posts, I drop everything to read it. And I learn so much.

    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.

  • pontussw 1 hour ago
    This is so incredibly well done
  • plagiarist 2 hours ago
    What a fantastic article!

    Makes me wish for a similar resource that would teach 3+ element optics, moving elements, and sortof get closer to modern lens design.

  • _jayhack_ 3 hours ago
    Great article. For another fantastic explainer on optics, see 3Blue1Brown's video on refraction: https://www.youtube.com/watch?v=KTzGBJPuJwM
  • brcmthrowaway 2 hours ago
    Does anyone know of a lens that can make a laser look like a spotlight?
    • aj7 1 hour ago
      Look up “beam expanding telescope.”
  • behnamoh 4 hours ago
    Can we donate to creative individuals like the OP so they keep making amazing stuff? This is the kind of output LLMs will not be able to produce any time soon.
    • sho_hn 3 hours ago
      "Make a Bartosz-style website about $topic" seems like a fun benchmark idea. Maybe more so than pelicans on bicycles.

      To be honest, though, this seems like ideal content for an LLM to produce. It's basically fact regurgitation.

    • macintux 4 hours ago
  • fsckboy 2 hours ago
    > ̶P̶i̶c̶t̶u̶r̶e̶s̶ ̶h̶a̶v̶e̶ Art has always been a meaningful part of the human experience. From the first cave drawings, to sketches and paintings, to modern photography, we’ve mastered the art of recording what we ̶s̶e̶e̶ think and feel.
    • Sharlin 2 hours ago
      Your "correction" does not make sense. "Pictures" and "art" are overlapping categories but neither is a subset of the other. Pictures in and of themselves are plenty fascinating to humans, without bringing art into the equation.
      • fsckboy 26 minutes ago
        it is your critique that does not make sense. I was not applying any hierarchy or subsetting whatsoever. Inseparable unity would be closer to the point.

        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.

  • andyfilms1 4 hours ago
    Doesn't seem to work in Firefox. :(
    • uhoh-itsmaciek 4 hours ago
      FF on Android seems to work fine here. What problem are you seeing?
    • mcdonje 4 hours ago
      Works fine for me with Firefox on Debian. Are you sure you don't have an extension breaking it?
    • fsckboy 2 hours ago
      I use firefox with javascript mostly off (UMatrix) but when I turned it on for fonts.googleapis.com the site and sliders all seem to worke. then I turned it on for gstatic.com fonts.gstatic.com , and not sure if that changed anything else. I'm on linux desktop
    • cfraenkel 3 hours ago
      Also works in Firefox (144.0.2) / MacOS (10.15)
    • compiler-guy 3 hours ago
      Working fine on Firefox for IOS.
  • unit149 3 hours ago
    [dead]
  • ChrisArchitect 3 hours ago
  • yazide 4 hours ago
    [flagged]