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Cameras and Lenses

ciechanow.ski

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Re: Cameras and Lenses

#221

Post by dang »

echelon wrote: post #138
kepler1 wrote: post #129

Earlier quoted context omitted.

I'll share something with you. The level of consideration you have for people who are no more than 1% of the population is admirable. Very admirable, in comparison with the actual large problems that I'm sure you pay 0% attention to each day, and do make assumptions about. So very admirable that you go out of your way to bring this to the level of everyone having to select a pronoun in their dropdown menu because you…

You're lashing out in anger. Calm yourself. It seems like you dislike trans folk. I'm not sure what they did to hurt you, but I suspect your fears and hate are the result of conditioning. What harm is it to use singular "they"? It avoids assumptions. It also avoids sexism. Do you want a world where all contributions are assumed to come from men? You've got a lot of fear and anger. Reflect on it. Let it go. I don't kn…

Please don't go into personal attack, and please stop posting unsubstantive and/or flamewar comments to HN. You've unfortunately been doing a lot of that lately, and it's not what this site is for.

https://news.ycombinator.com/newsguidelines.html

Re: Cameras and Lenses

#222

Post by HexagonalKitten »

mercer wrote: post #215
antonfire wrote: post #209

Earlier quoted context omitted.

Alright, I'm pretty burned out on this conversation so this is gonna be my last post. It's been distracting me and I want my real life back. I'll just try to wrap up the bits I find interesting. > But if you mean, would I spot Blair if I didn't know them? That's more or less what I mean, but also, would you, on top of that, expect me to spot the same thing? > Do you think this means I'm reading their gender expressio…

> Alright, I'm pretty burned out on this conversation so this is gonna be my last post. I sometimes try to have proper conversation, but these days try to make sure I'm not dealing with some form of alt-right bandwagon trolling by checking comment histories. Every single HexagonalKitten comment so far has been about how others get all upset about things, and, of course, 'immigration issues'. It's not that I have an i…

So, what's your conclusion of one day of posting history? Far-Right? Alt-right? Full on Notsee? Transphoooooobe? Paid Russian?

As far as group thinker goes, lol. I'm in the 5% side, against he 95% braying mob who dox and torment people all the time. This used to just be common sense, for instance that you can't medicate children to be the other sex, and now people insist that up is down. I'm saying what I said ten years ago, and barring an actual change in human biology, what I'll be saying in another ten years.

But since you brought up immigration issues, do you expect to see an alt-right person (such as you seem to believe I am) saying that race is not an issue? That immigration shouldn't be stopped? Where does that fit in your categorization? Could you describe what a moderate, liberal, Parisian view would be, such that you could judge mine against it?

Re: Cameras and Lenses

#223

Post by perlgeek »

The_Colonel wrote: post #35

I have a question for the more knowledgeable: Color filters on the sensor split the light into three wavelength ranges - red, green, blue. Then photosites measure intensity of light, which means that sensor only knows that the incoming photon is "roughly green", but doesn't actually recognize its precise wavelength. So e.g. when the light is pure orange, it falls down into red wavelength range and is counted as red.…

Your eyes cannot see orange directly, but as an overlap of different intensities of the stimulation of different receptors in the base colors.

So as long as the filters in the camera have roughly the same transmission curve as the sensitivity curve of the color receptors, all is good.

However, to animals (or hypothetical aliens) with other color receptors, the images produced by photo prints and screens would look quite weird, with colors all wrong.

Re: Cameras and Lenses

#224

Post by ddoice »

krosaen wrote: post #73

Looking at the page source I'm doubly impressed there seems to be no use of third party libraries. I personally happily use three.js, but still, wow. https://ciechanow.ski/js/base.js https://ciechanow.ski/js/lenses.js

I'm speechless, even in a mid-end android phone every animation is smooth, is like dark magic to me.

Re: Cameras and Lenses

#225

Post by ddoice »

sohkamyung wrote: post #61

The website sliders don't work well with a touch interface. If I use a mouse, I can smoothly move the slider values. But attempting to tap and slide them either has no response or makes the slide move to the extreme left or right. I'm using Firefox (Nightly) on a Windows 10 tablet (Microsoft Surface Go).

Firefox on Android here, every animation works flawlessly.

Re: Cameras and Lenses

#226

Post by sudosysgen »

hnuser123456 wrote: post #216
echelon wrote: post #8

Earlier quoted context omitted.

You'd like their other work : https://ciechanow.ski/lights-and-shadows/ https://ciechanow.ski/gears/ https://ciechanow.ski/tesseract/ Etc. Check out the whole blog! It's amazing. These are some of the most intuitive explanations coupled with the slickest animation / demo work I've ever seen. All of that put together into crystal clear educational material is such a rare gem and requires incredible talent. Impressive…

Regarding the lights and shadows articles, how they hell are they getting raytraced-quality lighting, with no noise, with changes to the scene in realtime?? Are these all pre-rendered PNGs?

Probably closed solutions to those simple lighting situations.

Re: Cameras and Lenses

#227

Post by sudosysgen »

whatshisface wrote: post #112
daralthus wrote: post #109

The only thing better than a pinhole camera is a pinhole camera with multiple holes. Let me explain: When you have two holes (apertures), their images would likely overlap (depending on the arrangement). Imagine you took two photos from a few millimetres apart to the left and to the right, then you superimposed them. Some areas would look ok (as both views saw the same distant object) and some would be less ok (of ob…

> That "infinitely many overlaps" I was talking about happens with lenses too and is essentially a convolution where you convolve the image with itself (actually many different perspectives of itself if I am correct). Which is just the Fourier transform. That statement is a bit muddled, let me unpack it. The infinitely many overlaps thing can be expressed mathematically as the convolution of the image with a function…

Pinhole lenses create visible diffraction effects pretty fast. Actually, even normal lenses cause diffraction at small ~f/11-f/22 apertures.

Re: Cameras and Lenses

#228

Post by sudosysgen »

contingencies wrote: post #182

For a markedly less engineering oriented introduction see https://en.wikibooks.org/wiki/Modern_Photography/The_camera One interesting thing I learned recently is how they make cheap plastic lenses, and the fact that plastic lenses were invented by an Australian. They are created by choosing a polymer with good optical properties and then thermoforming it by carefully applying air pressure to raise a rounded shape to…

This works for some lens shapes. For most though, molding is necessary.

Re: Cameras and Lenses

#229

Post by Double_Cast »

chandlerh wrote: post #113

Great article. One thing that's always stumped me as an amateur photographer is how an object is "in focus" when the rays from that object coverage to the smallest point, thus the smallest amount of pixels are getting hit. It would seem to me you would want to collect the max amount of information and thus use more of the sensor. How does converging to less of the sensor give you a sharper photo?

Ideally, the mapping from object to image is injective. What you're proposing will lead to "hash collisions" aka blurriness, since each point in the object will bleed colors into neighboring points in the image.

The entire object doesn't get collapsed to a single point. Rather, a single point of the object radiates light in all directions. A lens then captures a fraction of that radiation and collapses it back down to a single point. Then we iterate over each point in the scene with a "for each".

Re: Cameras and Lenses

#230

Post by martomi »

strogonoff wrote: post #13

Lately an area of interest of mine in digital photography in particular is scene-referred vs. output-referred image formats and subjective perception. The author (justifiably) walks around this topic in his camera sensor overview, but the data captured by a sensor from photons hitting it doesn’t really contain a readily viewable image. Data values captured by a modern camera far exceed the ranges that can be reproduc…

If I understand correctly, you're looking for a simplified RAW image editor? Many digital cameras allow storing RAW images alongside JPEG. The viewer can then load the RAW images into any (web-based) image viewer/editor that supports RAW format and have full control over tone mapping.

The tool interface needs to be simplified to make it a better fit for the use-case you present but I don't see computing power as a bottleneck.

Of course they'd still be limited by the dynamic range of the camera. This can also be resolved by calculating irradiance map based on multiple RAW images taken with different exposure times.

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