July 21, 2026

A Hole In The Wall Started Your Selfies

A Hole In The Wall Started Your Selfies

Send us Fan Mail A photograph feels simple until you ask the one question that started it all: how do we make the picture stay? We follow that question back more than 2,000 years to a tiny hole in a wall, an upside-down street scene, and the discovery that light follows rules. From Mozi’s early explanation of inverted images to Aristotle’s eclipse crescents under a tree, and Ibn al-Haytham’s experiments that helped define modern optics and the scientific method, the origin story of photograph...

Send us Fan Mail

A photograph feels simple until you ask the one question that started it all: how do we make the picture stay? We follow that question back more than 2,000 years to a tiny hole in a wall, an upside-down street scene, and the discovery that light follows rules. From Mozi’s early explanation of inverted images to Aristotle’s eclipse crescents under a tree, and Ibn al-Haytham’s experiments that helped define modern optics and the scientific method, the origin story of photography is really a story about curiosity that refuses to quit.

From there, the rabbit hole runs straight into the camera obscura, Renaissance artists, and Leonardo da Vinci realizing the human eye works like a camera. Then the pace picks up in rural France, where Niépce finally captures the first permanent photograph using bitumen of Judea, even if it takes roughly eight hours. Daguerre makes photography practical with the daguerreotype, Talbot makes it reproducible with negatives and prints, and the world starts to change because images can finally travel, multiply, and endure.

We also break down how a camera works in plain language: lens, aperture, shutter speed, film chemistry, and digital sensors. And once photography becomes accessible through Kodak and the Brownie, it stops being just a technical invention and becomes a tool for memory, evidence, journalism, medicine, science, and perspective shifting images like Earthrise and the Pale Blue Dot. If you’ve ever wondered why we document everything from wars to sunsets, the answer might be more human than you expect.

Subscribe for more rabbit holes, share this with a friend who loves big questions, and leave a review so more curious people can find the show. What’s one photo you’d keep if you could only save one?

00:00 - Light Paints A Picture

02:09 - Meet Your Rabbit Hole Host

03:43 - Mozi Aristotle And Early Optics

11:34 - Camera Obscura Meets Human Vision

16:44 - Niepce Daguerre And The Breakthrough

26:53 - Kodak Makes Photography Everyday

35:45 - Lens Aperture Shutter And Sensors

44:28 - Photos As Proof And Perspective

54:37 - Wild Myths Selfies And Kodak

01:04:11 - Capturing Life Not Just Light

01:13:39 - Next Rabbit Hole Time And Farewell

Light Paints A Picture

SPEAKER_01

Every picture you've ever taken, every family portrait, every wedding picture, every selfie, every image that changed history exists mainly because over 2,000 years ago somebody just looked at a wall and saw something they couldn't believe. It was an image of the street outside reflected onto the wall in their room. There wasn't a camera, there was no film, no electricity either. Just a tiny little hole in their wall that projected the image of the outside. The only problem is it was upside down. So think about that for one second. For thousands of years, people could make light paint a picture. They just couldn't figure out how to make it stay. And honestly, I think that's one of the greatest human stories ever told. Because photography wasn't invented in a lab. It wasn't created overnight. It wasn't the work of one brilliant inventor who suddenly had their aha moment. It was just the results of more than 2,000 years of people asking one question. How do we make the picture stay? One person noticed something unusual, another would ask why. Someone else figured out how it worked, and then another person spent years trying to preserve it. Generation after generation, one question led to another, one discovery led to the next, one rabbit hole after another.

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Until eventually, humanity learned how to stop time. They could keep that image on the wall forever.

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So today we're going all the way back to where that story really begins. We're gonna go down the rabbit hole of photography.

Meet Your Rabbit Hole Host

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Welcome to ADHD and the theory of all the things, the podcast where every week we pick one topic and we don't stop until we understand how it changed the world. I'm your host, Andrew Perry. I'm an EMT writer, public speaker, and the world's probably biggest professional rabbit hole chaser. I have ADHD, which means one simple question has a tendency to turn into a 12-hour deep dive through history, science, psychology, engineering, and usually a dozen tabs that I forgot that I opened. The funny thing is, the deeper I dig, the more I realize that almost everything is connected. That's what this podcast is all about. Every week we'll take one question, one idea, one invention, one mystery, and we'll follow it all the way back to where it began. We'll meet people who change history and discover the stories nobody really talked about and uncover the surprising connections that make the whole world a lot more interesting than you'd expect. So, in true Alice in Wonderland fashion, let's follow the rabbit hole.

Mozi Aristotle And Early Optics

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How did humanity discover that light could paint a picture? Because here's something I never realized. Nobody invented the camera. Not really. The camera was discovered piece by piece over thousands of years. And it all started with something so ordinary that most people just would have ignored it. A tiny little hole in the wall. Literally, a tiny hole in the wall, not like some weird bar off the edge of an alley. An actual hole in the wall. Imagine it's 400 BC and you're living in ancient China. There's no electric lights, there's no telescopes, there's no eyeglasses, not what you would consider eyeglasses. There's no scientific instruments that we use today. There's a crude version of a few of them, but in general, if you saw it today, you would have no idea what it was. Honestly, the world's still full of mysteries in 400 BC. There's a lot left to discover. Now imagine stepping into a completely dark room, like no light at all. Not dim, dark. The only light comes through a tiny hole in the wall. Like a little bitty hole. As your eyes adjust, something impossible begins to appear. Just on the wall across from you, there's a picture. Not a shadow, it's not a reflection, it's a real image. You can see the trees outside, people walking by, birds are flying way over their heads. Every movement is perfectly recreated. Except the image is upside down. So put yourself in that moment. You have no idea what a lens is, you have no idea what photons are, you don't even know what optics are.

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How would you explain what you're seeing? Magic? The gods? A trick? Well, one guy decided not to guess.

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He decided to observe it, and his name was Moatsy. If you've never heard of him before, you're not alone. Because I didn't either until I started digging into this pretty hard. But today, I'm gonna introduce you to him. And he helped begin one of the greatest scientific stories ever told. Mozi was a philosopher, an engineer.

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And more than anything, he was curious, which if you're here, so are you.

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In one of his writings, he described what happened when light entered a dark room through a tiny opening. He wrote that the image becomes inverted because the rays of light travel in straight lines and cross at the opening before reaching the wall beyond it. So think about that. More than 2,000 years ago, before the first picture was ever taken, somebody realized that light had to follow rules. It's not random. It's, I mean, it's if you observe it carefully enough, it will tell you what it's doing. And honestly, I think that's ridiculous. Because this wasn't just the beginning of photography, it was the beginning of somebody asking why. Fast forward to a couple hundred years later, on the other side of the world, another curious mind stumbled into the same mystery. And his name was Aristotle. Now you've probably heard of Aristotle, but I bet you've never heard this story. One day, while he was observing a partial solar eclipse, Aristotle noticed something off about the ground. He looked underneath a tree and saw hundreds of tiny crescents, like little crescent shapes, scattered across the ground. So each gap between the leaves, no matter how oddly shaped they were, it was projecting the exact same image of the eclipsed sun onto the grass. Every little opening between those leaves became its own tiny camera. So can you imagine seeing that? You're standing under a tree, and suddenly the ground is covered in tiny copies of the sun. That would have stopped me dead in my tracks. Like it well, it stopped Aristotle too. Instead of simply admiring it, he wrote about it. Because that's that's what curious people do.

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They don't just notice something interesting and move on with their day. They try to understand it. Then, for more than a thousand years, the trail goes completely quiet.

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Not because somebody stopped asking questions, but because the answers hadn't caught up yet. Until one more guy shows up. Around the year 1000, during what's known as the Islamic Golden Age, a scientist named Iban Al Haytham. You're gonna have to forgive me if I mispronounce that because that is a that's a lot. He became obsessed with one question. How do we actually see? At the time, many people believed that vision worked because our eyes somehow shot laser beams out into the world. It sounds strange today, but think about it back then. That's all they had to go on. But that idea had survived for centuries. Al Hytham wasn't satisfied with that. So he did something that seems obvious to us now, but back then it was revolutionary. He experimented again and again and again. He would block light, redirect it, he would build dark rooms, he'd punch tiny little holes in shutters, and he would watch and measure and question everything. And eventually he reached a conclusion that changed science forever. Light doesn't come from our eyes, it comes to our eyes. It travels in straight lines, and when those rays pass through a very small opening, they cross. Sounds familiar, doesn't it? We rediscover a few things here. The top of the tree becomes the bottom of the image. The bottom of the tree becomes the top of the image. That's why the picture is upside down. It wasn't magic, it was physics. Al Hythem recorded these discoveries in this huge seven-volume work called The Book of Optics. He explored how light behaves, how reflection and refraction work, how lenses focus images, and how human vision actually functions. Historians, they all kind of often call him the father of the scientific method because he insisted that ideas should be tested properly and not accepted just because someone famous believed in it. Without him, there's a real chance photography would have been delayed by another thousand, two thousand years. We would have no optics, no cameras, no telescopes, no microscopes, no eyeglasses. One rabbit hole changed all of that.

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And then a little bit, a little bit away from that, we've got one more guy.

Camera Obscura Meets Human Vision

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And I promise you, you've heard of this guy. Leonardo da Vinci. You probably know him because he painted the Mona Lisa, but we're just gonna we're gonna know him for something else today. Today, he can take a back seat. But today, I want you to know him for something else. We're gonna go. Leonardo was fascinated by the camera obscura. That's what they started to call this thing. The tiny little hole in the wall that projects light across the room. Camera obscura. In his notebooks, he described a dark room with a tiny opening projecting the outside world onto the wall. When the images of illuminated objects pass through a wall, round hole, into a very dark room, you will catch these objects on a white paper and they will appear upside down.

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That's what Leonardo wrote. But he didn't stop there. He realized something extraordinary.

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The human eye works almost exactly the same way. Light enters through a small opening, our people, and it's focused by the lens inside of our eye, and an upside-down image forms on the retina. Your brain takes care of the rest. So think about that. 500 years ago, Leonardo was comparing the human eye to what was essentially a camera.

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Way before cameras existed. I consider that pretty incredible. But we're gonna move on from old Leo and we're gonna go a little bit more.

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By the Renaissance, artists all the way across Europe were using these devices called camera obscuras. So the name in Latin, it simply means dark chamber or dark room. Some of these were entire rooms. Other people would make these beautiful little wooden boxes with lenses and mirrors. And artists would point them towards a landscape, and suddenly a perfectly detailed image appeared on a piece of paper, and they could trace it.

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And y'all thought tracing was just something you did in elementary school. They could capture a perfect perspective.

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They could paint with astonishing realism. Like they could have the perfect some of the paintings that you know and recognize today were used, like they were created using the camera obscura. Now there's a lot a lot that goes in with that too. You still have tattletales in the art scene who still say that some people use this and use that and use the camera obscura, so that's cheating. You still have to have a whole art behind that. You can't just trace something and it look fantastic. You still have to have color knowledge and technique and everything like that just to make the image look good. So for the first time, human beings could project reality itself. There was just one small problem that kind of got got under everybody's skin. The image would not stick around. The minute the light disappeared, the picture is gone. It couldn't be saved, it couldn't be shared, it couldn't survive. So imagine trying to paint a picture. You've got the camera obscure out first thing in the morning, and your image is projecting. You're working on tracing and getting everything done, and then a big old rainstorm shows up, and all of your light is gone.

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What do you do? Just wait. For over 2,000 years, that's I mean, that's kind of how everything went.

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Humanity had learned how to make light paint a picture, but now somebody had to figure out how to make the light leave one behind. And so far, we've figured out how to project an image. The camera obscura worked beautifully. Like the artists loved it, scientists studied it, philosophers wrote about it. But there was one problem that nobody had been able to solve yet. The picture just never stayed. It disappeared. The moment the light went away, so did the image. Imagine spending hours looking at the most beautiful landscape you've ever seen, only to watch it vanish forever. Or at least until the sun came back out. That question haunted inventors for centuries.

Niepce Daguerre And The Breakthrough

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What if the pitcher could stay? That question would launch one of the greatest scientific races in history. We'll start the story in rural France with a man named Nisophore Nieps. And I'm not entirely positive that's how you pronounce that, but that's what that's what I'm going with. If you looked at him today, you probably wouldn't think, you know, there's the guy who's about to change history. He wasn't a celebrity, he wasn't backed by a university, he wasn't running a famous lab. He was simply obsessed. He was obsessed with finding a way to let nature draw itself. That's what he told everyone. He wanted nature to draw itself. In the early 1800s, printing images was difficult and expensive. If you wanted an illustration in a book, an artist had to engrave it by hand. So Nieps wondered what if light could do the work for us. He started experimenting. And when I say experimenting, I mean years of failure. Different metals, different chemicals, different varnishes, different exposure times. Some images disappeared, some washed away, some never appeared at all. Imagine waking up every morning and thinking, you know, maybe today is the day that this works. And then nothing. Again and again and again for years, every day. Most people would have quit. Nieps didn't. Finally, around 1826 or 1827, everything changed. He coated a pewter plate with a naturally occurring substance called bitumen of Judea. It's a type of asphalt that hardens when it gets exposed to light. So he placed that plate inside of the camera obscura and pointed it out the window of his house. He opened the shutter and he waited. He didn't wait for one second, he didn't wait for one minute. He waited not even for an hour.

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About eight hours. Maybe a little bit longer. Can you imagine that?

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Clouds are drifting by, the sun is moving, you know, just across the sky the whole time. The world is changing while the camera is quietly sitting there trying to take a picture. Can you imagine trying to tell your kid to sit still in the same spot for eight hours?

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Yeah. When he finally developed the plate, there it was. The rooftops outside his window. Really blurry, super faint.

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But by today's standards, it's honestly not very impressive. But it didn't matter. Because for the first time in human history, light had left behind a permanent record of itself. The photograph still exists today. It's called the View from the Window at the Gras. And while that may look, it doesn't look like much. You're looking at the moment photography was actually born. And I'm gonna I'm gonna add in on the Facebook page ADHD and the theory of all the things. I'm going to put some pictures here of all of these things that we're talking about. So go give it a like, give it a follow, and take a look at them. Tell me what you think. Now, if this were a movie, this would be the happy ending. Except it wasn't. Because NEAPS still had a huge problem. And y'all already heard it. Eight hours. Nobody is taking a portrait if they have to sit still for an entire work day.

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Photography worked, but it wasn't practical yet.

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Enter another Frenchman, Louis Daguire. Deguire wasn't just an inventor, he was an artist. He was a showman, a theater designer. He understood something that Nieps didn't. If photography was ever going to change the world, it had to become faster. That's the only way it was going to change the world. Nieps knew it needed to be faster, but Daguerre knew that the only way anything was ever going to change. It's it's because it has to become faster. So the two men became partners in 1829. Together, they hoped to improve Nieps's process. But unfortunately, tragedy stuck struck and Nieps died in 1833. For many people, that would have been the end of the story. But for De Geer, this was just the beginning. He was kind of experimenting. He kept Experimenting despite the fact that he didn't have NEEPS with him anymore. And then one day, almost pretty much by accident, he discovered that mercury vapor. Bear with me here. Mercury vapor could develop a hidden image on a silver-coated copper plate. That meant the exposure times would drop dramatically from hours to minutes. It was revolutionary. In 1839, the French government announced Daguerre's invention to the world. The Daguerre type was born. That's what they called it, the Daguerre type. People stood in line for portraits. Cities, they opened photography studios almost overnight. For the first time in history, ordinary people, not just kings or the wealthy, could own an accurate image of themselves. So imagine what that meant. Like today we take thousands of pictures without even thinking. But back then, this one picture might be the only photograph someone ever had taken in their entire life. So families would treasure them, like soldiers would carry them into war. Parents kept them after children had grown. Photography had become deeply personal at this point. But while Daguier was becoming famous in France, something equally important was happening right across the English Channel. An English scholar named William Henry Fox Talbot had a different idea. Talbot had gotten a little frustrated while trying to sketch landscapes during his honeymoon in Italy. His drawings never looked the way that he wanted. So he asked himself, why can't the camera obscura draw the picture for me? So instead of creating a single metal image like De Guerre, Talbot created a paper negative. Now, at first glance, that doesn't sound very exciting, but it changed everything. Because one negative could produce multiple positive prints. So think about that. The Gyarotypes were one of a kind. That's all you got. If your house burned down, that photograph was gone forever. Talbot's process meant copies, books, newspapers, mass communication. Every printed photograph you've ever seen traces its family tree back to Talbot's idea. In many ways, the modern photograph owes as much to Talbot as it does to Daguerre. It's funny. When we think about inventions, we imagine one brilliant person just shouting Eureka. But that's almost never how history works. Photography wasn't invented by one person, it was built by one curious mind at a time. Mozzi noticed the mystery, Aristotle acknowledged it and saw it too. Al Haytham explained it. Oleo understood its connection to the eyeball. Artists perfected the camera obscura. Nieps captured the first permanent image. Daguerre made it practical. Talbot made it shareable. Each person solved one piece of the puzzle and then handed it off to the next. And that's one of my favorite things about history in general. The greatest inventions aren't usually moments, they're conversations. Conversations that sometimes last thousands of years. But even after all that, photography still had a long way to go. The people in those early photographs barely smiled. Color didn't exist. Cameras were heavy. Exposure times were still slow. Not eight hours, but they were still slow. And photography was about to become something no one, not even Nips, could have imagined. Because the next challenge wasn't capturing light anymore, it was putting a camera into everyone's hands.

Kodak Makes Photography Everyday

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So for the first time in history, people could capture reality. They could stop time, just pause the moment. But there was just one problem. Almost nobody could afford it. Early photography wasn't convenient, and it for sure wasn't cheap. And it definitely wasn't a casual thing. If you had your portrait taken in the 1840s, it was probably one of the biggest events of your year. You'd put on your nicest clothes, you'd fix your hair, you'd travel into town and sit perfectly still, sometimes for several minutes. Photographers even used metal braces behind people to keep their heads from moving. That's why so many early portraits look a little unsettling. Like I don't know if you've heard the story of you know taking when they used to take pictures of dead bodies just to have a picture of that person to remember them by, they would use braces to hold the dead body up so it would sit still and stay there long enough for the picture without falling over.

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It's a little unsettling.

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But so many of those early portraits look unsettling because no one's smiling. Nobody's moving. Everyone looks incredibly serious. Now, some people will tell you Victorians just didn't smile, but that's not entirely true. They absolutely did smile in everyday life. The problem was, if you smiled for 30 seconds, your face got tired. If you tried to hold a smile for several minutes, your picture was just a blurry mess because you'd be moving your mouth. So people relaxed their faces. And that's the expression history remembers. Like, just think about how strange that is. Your entire generation is remembered as serious just because of the limitations of the technology. So they think everyone from back then was just grumpy. Even then, photography was still a luxury. The wealthy could afford it, but working class families could not. And that that meant something a little profound. For thousands of years, history had mostly been recorded by the rich, like kings and queens, politicians, generals. The average person, they just lived. They lived and they loved and they worked, they raised children, and then they disappeared with no visual record they ever existed. Then one man decided to change that. His name was George Eastman. And if you've ever heard the name Kodak, you've heard of George Eastman. Eastman wasn't trying to invent a better camera, he was trying to make photography simple. So in the late 1800s, photography was still pretty complicated. Like there were glass plates, chemicals, really bulky equipment. You almost needed to be part scientist just to take a single picture.

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Eastman thought that was ridiculous.

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Like he believed photography should belong to everybody. So in 1888, he introduced something that was just revolutionary when it came to photography. It was a small box camera preloaded with enough film for 100 pictures. And when you finished the role, you didn't develop it yourself. You mailed the entire camera back to Kodak. They developed the pictures and then reloaded the camera and mailed it back to you. Their slogan became one of the most famous marketing campaigns in history. It was you press the button and we do the rest. Then I love that slogan because it wasn't really selling a camera, it was selling freedom. Freedom from the complex chemistry and from complicated equipment, and freedom to simply enjoy the moment. Photography was no longer reserved for professionals. It became something that anyone could do. And then came what might be one of the most important cameras ever made, ever. Not because it was the best, because it was the most accessible. In 1900, Kodak introduced the brownie camera. It sold for just one dollar. One dollar. To put that into perspective, photography had gone from being a luxury reserved for the wealthy to something many ordinary families could actually afford. Like even kids owned brownies. Parents carried brownies. Like families were documenting birthdays and vacations, uh, Christmas mornings, first days of school. For the first time, ordinary lives became part of history. I don't think we really appreciate how revolutionary that was because before photography, if your great-great-grandmother wasn't wealthy, you may never know what she looked like. Like her smile and her eyes, the way that she held her child could all disappear forever. Like photography changed that. A chance to be remembered. And I think that's why old family photographs feel so powerful in the first place. Like, have you ever picked up a faded black and white picture of someone you've never met? Like your great-grandmother or a relative whose name you don't even know? Like you look at that picture and then you realize they stopped being a name on the family tree and they're a person. You notice their expression and their clothes, the way they're standing. You start kind of wondering like, who were they? What made them laugh? What did they worry about? What do they dream about? Like one photograph can resurrect an entire life into your imagination. Like my son really loved the Coco movie. I feel like that relates a lot here because the photographs on the Ofrenda allowed the spirits to cross over the bridge and visit their families. The photograph is what kept the memory of them alive. So photography didn't just preserve history, it changed what history looked like. Newspapers could suddenly show readers what, like wars were happening thousands of miles away. Scientists documented discoveries instead of sketching them. Doctors photographed diseases to teach future physicians. Police departments began using mugshots and crime scene photography. Explorers would bring back images instead of descriptions. The Wright brothers photographed flight for the first time. The Hubble Space Telescope photographs galaxies billions of light years away. Neil Armstrong's footprint on the moon. We don't just read about it, we can see it. Photography didn't just record history, it became evidence. Like if there's one thing that surprised me while researching all this, it's that cameras never really became smaller because people wanted to have better technology. They became smaller because people wanted to capture everyday life. Like, not kings or presidents or celebrity. Well, yeah, they still want to capture celebrities, but they just wanted to take pictures of their kids playing in the backyard. They wanted pictures of their dog sleeping on the porch or a birthday cake or a fishing trip, or those pictures that everybody takes of the sunset. The little moments, because those are the moments we end up missing the most. And maybe that was the greatest gift photography gave us. It was the ability to grab a memory and cherish it. Like it said, your life matters too. Your family deserves to be remembered. Your ordinary Tuesday might become someone's treasured photograph a hundred years from now. When George Eastman made photography affordable, he didn't just sell cameras. He gave millions of people the ability to tell their own stories. I think that's one of the coolest like revolutions in human history is well, that you can tell your own story and you have the proof behind it to do it.

Lens Aperture Shutter And Sensors

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Of course, by now we've talked a lot about photographs, but we still haven't answered a pretty important question. Like, how does a camera actually capture light in the first place? Let's open one up and take a look inside. How does this thing actually work? And here's the funny part: you've been carrying around a pair of cameras your entire life. According to, you know, Leonardo, Da Vinci, and all the rest of them, they're called your eyes. Seriously, you're your eyes and a modern camera have the exact same job. They both collect light, they both focus it and create an image. They both send that image somewhere to be interpreted. Your eyes send it to your brain. A camera sends it to film. Well, nowadays to a digital sensor. Once you realize that, cameras suddenly aren't as mysterious as you may think. They're literally just trying to imitate something nature figured out a long, long time ago. We've had eyes for millions of years. So let's imagine you're standing outside on a sunny afternoon and you're looking at a big old oak tree. And here's something that's happening. Even though you can't see it, light from the sun is bouncing off every single leaf and every branch and every inch of that tree, and it's bouncing in every direction imaginable. Millions of directions. Actually, billions of directions. There's billions of tiny rays of light that are flying towards you every second. Now, here's the problem. If you just let all that light into a camera, you'd get just insanity. That'd be like trying to listen to a hundred people talking all at once. The image would just be a blurry mess or just really, really bright. Like to the point to where it's just white. So the camera needs a traffic cop. That would be the lens. Think of the lens as like a conductor leading an orchestra. Its entire job is to organize the incoming light instead of letting every every light ray go wherever it wants. The curved glass inside the lens bends the rays. It guides all of them so they all meet at exactly the right place. If you've ever used a magnifying glass to focus sunlight, you've already kind of seen this happen. The glass bends the light until it converges into one tiny point. A camera lens does the same thing. Just with incredible precision. When everything lines up, the picture becomes sharp. When it doesn't, it's out of focus. That's literally what focusing is. You're just moving pieces of glass until the light lines up perfectly. Now, the light has made it through the lens, but there's another problem. What if there's too much? Imagine walking outside at noon and then immediately walking into a dark movie theater. Your eyes struggle for a second. Why? Because they have to adjust to how much light they're letting in. Cameras have to do the exact same thing. Inside every camera is something called an aperture. Don't let the fancy name scare you. It's basically just a tiny adjustable hole. The bigger the hole is, the more light gets let in. The smaller the hole is, the less light gets in. Your pupil does exactly the same thing in bright sunlight or at the doctor's office when they shine that really bright light into your eye with that magnifying glass in the doctor's hands, it your pupil gets really tiny. That's why they dilate your eyes at the eye doctor. It makes them huge. So when he gets that little magnifying glass in his hands and he can look back there and see inside of your eye. In the dark, your pupil gets really wide.

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Your camera is basically copying your eye. Again.

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And we've got one last decision to make. How long do you let the light in? Because remember, light never stops moving. So if the camera leaves that aperture open too long, anything moving starts to blur. That's where the shutter comes in. Think of the shutter like a set of curtains. Open it, light comes in, close, the moment is over. So that's why photographers talk about shutter speed. If the shutter opens for one thousandth of a second, you can freeze a hummingbird's wings. If it stays open for 30 seconds, stars, that's how you get the glowing headlights driving down the highway, or stars that look like they're streaking across the sky. Same thing. Same camera, just a different amount of time that the shutter is open. You're not changing the picture, you're changing how long the camera gets to watch the picture. That's the way I like thinking about it. You don't change the picture itself, you're just changing how long the camera gets to watch. So now the camera has collected the light. It's focused it, it's controlled how much comes in, controlled how long it stays. Now what? But the light has to land somewhere. For most photography's history, it landed on film. Film is coated with tiny crystals made from silver compounds. When the light hits those crystals, it changes them chemically. Like the image is there. But you can't see it yet. It's called a latent image. Kind of like invisible ink. The picture exists, it just needs to be developed. That's why photographers disappeared into dark rooms. Developing chemicals revealed what light had already put on the film. I don't know about you, but that's kind of like real magic. That's the way I've always thought about it is that film photography is literal magic. The picture was sitting there the whole time. You had to go into this room and uncover it. Digital camos work a little different. Instead of chemicals, they use electronics. Imagine replacing every silver crystal on a piece of film with a microscopic bucket. Each bucket catches light. That brighter the brighter the spot in the scene, the more light fills the bucket. So millions of these tiny buckets called pixels work together when the camera processor reads them. So it all it turns all that information into your picture. So whether you're shooting a hundred-year-old film camera or you know your iPhone 17, you're really doing the same thing. You're collecting light. The technology changed, but the idea behind it never did. Here's the part that blew my mind, though. Every single photograph you've ever taken, every wedding, graduation, every family vacation, or picture of your dog, or those sunrises, or those awkward selfies, every historic image, they've all they're made from exactly the same raw material. Not film or pixels or memory cards, but light. That's all a photograph has ever been. Ever. That's all it has ever been and all it ever will be. Is light captured and preserved? And maybe that's why photography feels so special. It's because when you press the shutter, you're not taking a picture, you're borrowing a tiny fraction of a second all to yourself forever. Now that we know how a camera works, let's look at what other photographers have done with that power.

Photos As Proof And Perspective

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Because some photographs didn't just capture moments, they altered the course of the world itself. So in the early 1900s, photography had become something pretty much anyone could do. Families were documenting their birthdays and vacations, pets, you know, ordinary life. But something was happening. A little a little bigger. Photography wasn't just preserving memories anymore, it was changing the way humanity understood the universe itself. Because before photography, you usually had to trust someone else's description. After photography, you could see it with your own eyes. And that changed everything. So let's start with journalism. Imagine it's the mid-1800s, and a newspaper reports that a war is happening a hundred miles away. Before photography, you had two choices: believe the writer or don't. Maybe there was a sketch, or maybe there was an artist's interpretation, but there was always room for doubt. And then cameras arrived. Suddenly, people weren't just reading about history, they were witnessing it. The American Civil War became one of the most major, first major conflicts to be extensively photographed. Like photographers like Matthew Brady and his team brought home haunting images of battlefields and soldiers. For the first time, people saw the true cost of war. They didn't see heroic paintings or not romantic stories, or they saw real people and real loss. Some historians argue that those photographs permanently changed how the public viewed the war in the first place. It's one thing to hear that thousands died, it's another thing entirely to look into the face of someone who did. Photography became something else, too. Evidence. Like if you ever watched a detective show, you've seen crime scene photographs. Before cameras, investigators relied on sketches and handwritten descriptions. After cameras, the scene could be preserved exactly the way that it was. Every footprint, every broken window, every piece of evidence. Photography didn't replace detectives, it gave them access to a huge memory. Medicine changed forever, too. Doctors were able to photograph diseases, injuries, surgeries, medical conditions, instead of relying on drawings. So students could actually study real patients. They could look at the images and study that and get a better understanding of the profession they're going into. Medicine became more and more accurate, more consistent. Like back before photography was, you know what I'm talking about, the joke that everyone says, you know, oh, I've they've got a fever or they've got this or they've got that, and somebody's like, oh, you know what? Give them a drink of, you know, acid. Now you could actually have some evidence to go along with that. So today, I mean, everything from X-rays to MRIs, CTs, ultrasounds, even though they use different technology, they're all descendants of the same idea. They use images to understand what we can't easily see. Science might be where photography had its biggest impact, though. Scientists suddenly had something they never had before. They had proof. Think about astronomy. Before photography, astronomers looked through telescopes and made sketches and hoped that they remembered what they'd actually seen. Then cameras were attached to telescopes, and suddenly a faint galaxy could be photographed over a couple hours, capturing details that no human eye could ever see in real time. The same thing happened under microscopes. Tiny organisms and cells, bacteria. So if you've never heard of a water bear, I suggest you look it up because without photography, we would never know that little thing even existed. I'll add a picture of it to the Facebook page so you can see. But now you could actually have pictures of these little organisms. They could be studied, they could be shared with scientists all over the world. Knowledge exploded. Because now discoveries didn't live in one scientist's notebook to maybe eventually be published or discovered by someone else. They lived in the photographs that literally anyone could examine. And then humanity pointed cameras somewhere we'd never pointed them before, really, which was up, like way up. When astronauts carried cameras into space, photography stopped documenting Earth and it started documenting the universe. Think about some of the most famous photographs ever taken. Earth rise. That was the image taken during Apollo 8, like the Earth. It's rising above the gray horizon of the moon. For the first time, humanity saw home from somewhere else. So one of the astronauts, uh Bill Anders, said that we came all this way to explore the moon, and the most important thing that we discovered was the Earth. And I love that quote because it's true. That one photograph changed how millions of people thought about our planet. It wasn't divided by countries anymore. It wasn't political. It was one small blue orb floating in the darkness. Years later came another photograph, the pale blue dot, taken by Voyager 1 from nearly four billion with a B miles away. Carl Sagan, he was looking at the tiny speck, barely visible in a single beam of sunlight, and wrote words that echoed everywhere. He said, Look again at that dot. That's here, that's home, that's us. One photograph changed our whole perspective on humanity. That tiny little dot. Photography also changed something much more personal. How we remember. Think about this. Before photography, memory depended on stories. My grandfather had blue eyes. My grandmother loved to laugh. You had to imagine them. And now you don't have to imagine, you can see it. You look into the eyes of someone who died a hundred years ago. There's something a little almost haunting about that. It's like shaking hands with history. And now here we are, the 21st century. Many of us carry cameras everywhere we go. In fact, there are probably more cameras on Earth today than there are people. Think about how wild that is. Like the average smartphone has had the average smartphone has more computing power than the guidance computer that landed Apollo 11 on the moon. And we use it to take pictures of our lunch. Like I kind of love that because we've gone from waiting eight hours for a single blurry photograph that you almost couldn't even tell what it is to complaining because our phone took half a second to focus. Perspective is everything. Of course, photography has changed again. Social media transformed the camera from something we use to remember into something we use to communicate. Like a single image around can just it can travel around the world in seconds. It can expose injustice, it can launch businesses, it can start movements, reunite families, it can teach people, inspire millions, or let's be honest, convince everybody that you had a better vacation than you actually did. Photography has become its own language. Sometimes one image says more than a thousand words. And sometimes it changes history before the words are ever written. The thing that surprised me the most when I was going through and building this chapter and researching was that, like we've said, photography never really changed. It didn't change at its core. The technology did, the camera got smaller, the cameras, the pictures got sharper, the sharing got faster. But the reason we take photographs has stayed very constant. We don't take pictures because cameras exist. We take pictures because moments disappear.

Wild Myths Selfies And Kodak

SPEAKER_01

So I think we're just going to do that with every episode right at the end of it. We'll just kind of go into a few wild facts or things that we didn't know. So we'll just call it the segment that's wild. But these are facts and stories and myths and the little rabbit holes inside of the rabbit hole that either made me laugh or just made me want to stop and say, you know, no way. But let's see how many of these you already know. So nobody smiled in photographs. This is myth number one. So we covered that in there and we talked about it a little bit. You've heard of the people in the Victorian area that were just incredibly serious. Turns out it was just a myth. People did smile and they laughed and joked. The problem wasn't that they didn't want to smile, problem was the early camera cameras were painfully slow. And if you've had to hold the smile for 30 seconds, your face would start hurting too. Uh, the world's first selfie. Think selfies are, if you think they're a modern invention, that's that's not even close. Like I get that the cameras used to be really rough and slow, but think about trying to take a selfie back then. So in 1839, an amateur chemist named Robert Cornelius decided to experiment with the camera. He removed the lens cap and then ran into the frame and stood perfectly still and then ran back to close it. The result was what's widely considered the first photographic self-portrait, but it's it looks like somebody who just sprinted back to a camera. It's just a big blurry mess. Some things never change. The most viewed photograph in human history, close your eyes for a second. Picture this a bright green hill with the bluest sky you've ever seen, fluffy white clouds, and then a bunch of icons across the screen. If you ever used Windows XP, you already know the picture. It's called Bliss. The photographer Charles O'Rear took it in California's Napa Valley in 1996. Microsoft bought the image and it became the default wallpaper on hundreds of millions of computers. So think about that. Out of every photograph ever taken, a grassy hill may be the most viewed image in human history. And next, Kodak invented the future and then got afraid of it. So this one, this is this is the one that you're really gonna love. Kodak, how we talked about how they just made it accessible for everybody and then send it in. So this one just I got lost on this one. In 1975, there was a Kodak engineer named Steven Sassan who built the world's first digital camera. Okay, look at this. A Kodak engineer built the world's first digital camera. Now it weighed about eight pounds and it recorded images to a cassette tape and took about 23 seconds to save a single black and white picture. But here's what happened. When the executives at Kodak saw it, they weren't exactly thrilled with it. Why? Because Kodak made most of its money selling film. A digital camera threatened their entire business model. Instead of leading the revolution, like leading the digital revolution, they hesitated. So Kodak was like, you know what, we're just gonna shelf this for a little while. And it kind of started their entire downfall. Other companies figured out the same thing, but they also sold film, but they didn't care. They knew that it was all gonna go that way eventually. So Kodak hesitated and other companies didn't. And one of the biggest names in photography ever, Kodak, eventually filed for bankruptcy. And sometimes the biggest threat to innovation is your own success. Abraham Lincoln. Listen to this. Abraham Lincoln and the power of a photograph. This is the one I never expected to find. Um, some historians believe a photograph may have helped Abraham Lincoln become president. In 1860, one of the photographers we talked about earlier, Matthew Brady, took a portrait of Lincoln in New York. Lincoln later said that Brady and the Cooper Institute speech made me president. So the speech mattered, but so did the photograph. Because, like we talked about earlier, for millions of Americans, it was the first time they had ever really even seen him before. Think about that. This like this day and age, you see everyone, especially if they're famous, especially the president. Could you imagine just not even knowing what the president looks like? Photography wasn't recording history at that point, it was shaping it. They they could see Lincoln. So if I had to pick one picture, like if I just had to pick one picture that changed the way that everybody views everything, it would be Earthrise. So this was Christmas Eve, and Apollo 8 is orbiting the moon. So astronaut Bill Anders looks out the window and suddenly he just sees Earth rising above the lunar horizon. He famously shouted, Quick, give me a color film. There's the Earth coming up. So the crew on the so the crew scramble to grab a camera. The image that they've captured has become become one of the most influential photographs ever taken. It inspired environmental movements, it's changed perspectives, and reminded millions of people that from space there are no borders, just one planet, one home. Then you have some people who say the earth is flat and square. It's yeah.

SPEAKER_00

The tiny blue dot is another another picture that I kind of like a lot. Then it's just a different way of thinking about it.

SPEAKER_01

They call it the pale blue dot. So it was in 1990, and Voyager 1 had nearly reached the edge of the solar system. And we talked about this earlier too. Carl Sagan in he had convinced NASA to turn the camera around one last time. And the Earth appeared as less than a single pixel. It was just a teeny tiny little bitty blue speck suspended in a ray of sunlight. Like Sagan, he wrote what I told you earlier. He said, look again and look at that dot. That's here, that's home, that's us. So every person you've ever loved, every war, every invention, empire, uh, every victory and failure happened on that tiny little blue dot. And if you've never read the rest of that passage, you should do yourself a favor. It's one of the coolest things ever written. Like Sagan wrote about it, and it just you should give it a read. It's really nice. The camera that went to the bottom of the ocean and the moon. So the one thing I noticed when I was researching the episode is that cameras have gone just about everywhere human has humans have. Like to the top of Mount Everest and to the deepest parts of the ocean, into active volcanoes and uh Antarctica, hurricanes, and even the moon. No matter where humans go, one of the first things that we pack is a camera. I guess we really are obsessed with bringing memories home, but my favorite fact, and here's here's the one thing I'll never forget, is every single photograph ever taken from Nieps's blurry rooftop in the 1820s to the selfie that someone took five seconds ago started exactly the same way. A little bit of light entered a dark space, and that's it. That's it. Everything else is just humanity getting better at preserving the light. And honestly, I mean, if you think about it, the inventions there, all we're doing is perfecting at this point. We're not creating anything new.

Capturing Life Not Just Light

SPEAKER_01

So after spending all this time researching photography, I kept asking myself one question. Out of everything I learned, what actually stuck with me? And I think the answer kind of surprised me is we're gonna wrap this rabbit hole up. But before we move on, um, if you forget everything else we talked about today, I want you to remember this. Photography wasn't invented because someone wanted a camera. It was invented because we refuse to let go of things. Humans as themselves want to hold on to things. They want to hold on to moments and memories. So photography was invented because we're stingy. Think about all the people that we met today, like Mozzi and Aristotle and Al Hytham, Leonardo da Vinci, Neps, Daguire, Talbot, George Eastman. None of them finished the story, but each one inherited part of the mystery. They solved one piece at a time. And then they handed the puzzle off to the next generation. Nobody built photography alone. Photography is what happens when curiosity survives longer than a lifetime. And honestly, I think that's true of almost every great human achievement. I figured I'd learn about About some inventors, maybe a few interesting dates, and talk about film versus digital, which is a whole argument in itself. Like, don't start that because everyone has their own opinions and it gets kind of wild sometimes. Uh, I figured I'd throw in some fun facts and call it a day. But that's not what happened. Not even close. Somewhere along the way, I realized this story was never really about cameras or photography in general. It's about people, it's about curiosity. I mean, think about it. For over 2,000 years, human beings looked at the exact same phenomenon, which was an upside-down image in a dark room. Most people probably looked at it and they thought, you know, huh, that's weird. And then they went about their day. But a handful of people couldn't let it go. Mozi couldn't, Aristotle couldn't, um, Al Haithum couldn't, Leonardo definitely couldn't, and then Nieps, he couldn't either. Each one looked at the exact same mystery, and instead of accepting it as it is, they asked one more question. And then one more after that. And that's something I keep noticing the more research into these rabbit holes I do. The people who change the world usually aren't the smartest people in the room. They're the ones who stay curious longer than everyone else. They're willing to sit with the question even when the answer might take years. They might even not be alive by the time the question is answered. It may take decades, or in photography's case, you know, more than 2,000 years. I love that. Because it makes history feel like less than a series of impossible geniuses and more like regular people who refuse to stop wondering. And then there's something else that really surprised me. Photography didn't just change technology, it changed memory itself. Think about the people in your life. Uh, your maybe your grandparents or someone you never got the chance to meet. Maybe somebody who's gone now. The odds are the first thing you think of is a picture, a photograph. Like you don't remember a birth certificate or a legal document. You remember a picture. A smile, a family vacation, a wedding, or you know, a Christmas morning in the gifts that you've got. You always take that picture whenever you're younger. You take the picture of the gifts. It's one frozen moment in a whole person's lifetime. That's what you remember. Photography gave us the ability to hold on to it way after the moment had passed. So I don't know. There's something really cool about that. And maybe that's why we take so many pictures today. Like people joke that we're obsessed with documenting everything, our coffee and our dogs, especially, sunsets, our kids. The concert we probably should have just enjoyed instead of having our phone up in the air or in our face. And sure, sometimes we do probably overdo it, but I don't think that's really what photography is about. I think we're trying to answer the exact same question that Nips was asking 200 years ago. How do we make this moment stay? Because every single one of us knows whether we admit it or not, that moment's not going to stick around very long. It disappears. Kids grow up, parents get older, friends move away, places change, people leave, life keeps moving, and a photograph stops it for just a just a brief second. A picture can't really stop time, but every once in a while it lets us visit. One of my favorite photographs is actually the one that's probably sitting in a box somewhere in your house. Not the famous ones, not Earthrise or the Moonlanding or any Pulitzer Prize winning picture. I'm talking about like the old family picture, the one with the old messed up edges and faded colors, the ones where people are wearing clothes that went out of style like 50 years ago. The picture where half the people have names you don't even know. Because every one of those pictures is proof that somebody lived. Somebody laughed, somebody loved, somebody mattered. That's the power of photography. You know, the title of this podcast is ADHD and the theory of all the things. And every episode, I kind of hope we end up finding a bigger idea than the one we started with. Like today, I think the bigger idea is photography wasn't just about capturing light. It's about capturing life. Light is just the tool that we use. Memory is the purpose, and that's why photography has survived every technological change we've thrown at it. Glass plates, film, Polaroids, digital cameras, smartphones, AI. The technology keeps changing, but the reason we pick up a camera never changes. We just we don't want to remember everything. We just desperately kind of hope we remember the moments that mattered. So the next time you take a picture, maybe just pause for a second and look at the people around you. Look where you are, and realize that this ordinary moment might become someone's favorite memory 20 years from now. And that's kind of incredible when you think about it. Like honestly, I think that's the biggest thing I've learned from this entire rabbit hole is photography didn't teach humanity how to take pictures.

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It reminded us that some moments are worth keeping forever.

SPEAKER_01

Now, while I was researching photography, I accidentally found another rabbit hole that I absolutely have to we gotta jump in. Because if cameras taught us how to capture light, then what taught us how to capture time?

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I have a feeling that's where we're headed next.

SPEAKER_01

And that's the end of our rabbit hole for this week. And I hope the next time you pick up your phone or dust off an old family picture, you don't just see a picture. I hope you see over 2,000 years of curiosity and countless people asking more questions, and humanity's incredible ability to turn wonder into reality. If there's one thing I hope you take away from today's episode, it's this. The world is a lot more interesting when you stop and ask why. And trust me, we're just getting started. Next time, we are gonna dive into another rabbit hole that's been shaping every second of our lives.

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Time. Who decided an hour would be 60 minutes?

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Or like, why do clocks look the way that they do? How do we go from watching shadows move across the ground to carrying mini clocks in our pockets? Why are we all so obsessed with knowing what time it is? I have a feeling that rabbit hole is going to go a lot deeper than I'm ready to go.

Next Rabbit Hole Time And Farewell

SPEAKER_01

If you enjoyed today's episode, I'd love for you to go follow the show on Facebook. It's uh ADHD and the theory of all the things. Leave a review, uh, share it with somebody who's just as curious as you are, because the best part about rabbit holes are the ones you fall intogether. I'm Andrew Perry. This has been ADHD in the theory of all the things. Every week we pick one topic and we don't stop until we understand how it changed the world. Until next time, stay curious and don't be afraid to follow the rabbit hole.