Leonardo da Vinci's Camera Obscura

One scientific concept that most intrigued Leonardo was optics, the science behind how the human eye works. In Leonardo's time, it was generally believed that the eye issued forth sight rays that would bounce off objects and then return to the eye, enabling the person to see.

Da Vinci had the idea that this was wrong, because it should take too long for such a ray to leave the eye, bounce off of something and then return to the eye.

To explain this suspicion, he used the example of the sun. He said the sun was so far away that should a person need to send forth sight rays to see it, it would most certainly take a month before they could return.

The fact is, this estimate on the sun's distance from the earth was pretty far off. Da Vinci believed it was 4,000 miles away. In reality, it’s 93 million miles away.

Leonardo da Vinci's Camera Obscura
Leonardo da Vinci's Camera Obscura
Leonardo's Drawing of the Human Eye
Leonardo's Drawing of the Human Eye

Dissecting Eyeballs

Leonardo came up with a way to dissect eyeballs: he boiled them in water until the whites hardened, then sliced them open.

Da Vinci and the Human Eye

Leonardo thought of the human eye as the most important organ in the body. In his diary, he wrote, “This is the eye, the chief and leader of all others,” and used up hundreds of pages jotting down ideas about how the eye functioned.

He went so far as to dissect human eyes to study them. He used his observations to develop a projector, bifocals, and even came up with the idea for contact lenses - even though he never actually made them.

Leonardo also conceived of a gigantic lens to harness solar energy for the dyeing and tanning industry. Today, historians even believe that he came up with the idea of a telescope long before Hans Lippershey, the Dutchman who is credited with inventing the telescope in 1608.

Leonardo wrote, “...in order to observe the nature of the planets, open the roof and bring the image of a single planet onto the base of a concave mirror. The image of the planet reflected by the base will show the surface of the planet much magnified.”

Camera Obscura
Camera Obscura

The First Photographs - Joseph Nicephore Niepce 1827

In spite of being called a camera, a camera obscura isn't really the kind of camera we know today - it has no ability to take a photo that we can put in a frame. The first real photos were taken by a French chemist called Joseph Nicephore Niepce in 1827. Niepce set up a camera obscura and placed a polished pewter plate coated with a kind of asphalt called bitumen of Judea in it.

After 8 hours, Niepce cleaned the plate with a mixture of white petroleum and lavender oil, which dissolved away the parts of the bitumen that had not been hardened by light. The outcome was the very first photograph in history. Obviously, Niepce couldn't take images of people, as the only way to capture an image was by leaving the pewter plate to sit in the sun for hours and hours.

How Leonardo's Camera Obscura Worked

The camera obscura was one of the most interesting optical inventions Leonardo worked with. He was not the first person to use one of these, but he was first to notice the similarity between the way a camera obscura worked and the way the human eye functioned.

A camera obscura is merely a dark box (or even a very dark room) with a very small hole in one wall that lets in light. Directly across from the hole the image from the outside world will be projected onto the wall upside down.

The reason this happens is that light travels in a straight line, but when some of the rays reflected from a bright subject pass through a small hole, they become distorted and end up as an upside-down image. Imagine trying to squeeze an object into a space that is too small for it.

How The Human Eye Works

Da Vinci noticed that this is exactly the way the human eye sees things: light reflects off the surface of the object you are looking at and travels through a small opening on the surface of the eye (your pupil), and the image ends up flipped upside down.

He wrote, “No image, even of the smallest object, enters the eye without being turned upside down.” But he couldn't seem to figure out how a human eye actually sees the image right-side up. He didn't know what we know, that the eye’s optic nerve transmits the image to the brain, which then flips it right-side up. So the only thing the camera obscura lacks is a brain to flip the image!

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Comments 5 comments

lisa.bom 4 years ago

Very interesting! I really enjoyed reading this.


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Anne Harrison 4 years ago from Australia

A great hub - the side boxes with extra details were an excellent idea. Voted up, looking forward to more.


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Vanderleelie 4 years ago from New Brunswick, Canada

A very good hub, with plenty of interesting facts about Leonardo and his scientific research on optics. He was so far ahead of his time with innovative thinking and clever inventions! I voted this article up and have shared it with other readers.


BAL 2 years ago

swag yolo


Damon 23 months ago

Εκεί κολλάς; Εδώ έχουν το δικαίωμα να χρησιμοποιήσουν ό,τι υλικό ποστάρεις στο Facebook, όποτε θέλουν, όπως θέλουν, εφ'όσον εξακολουθείς να είσαι μέλος με μόνη προϋπόθεση να μην παραβιάσουν τις ρυθμίσεις ιδιωτικότητάς σου (δηλ. να μη χρησιμοποιήσουν φωτογραφίες σου που δεν είναι δημόσιες).Ακόμα δικαιούνται να κρατούν "αντίγραφα ασφαλείας" ακόμα και όταν διαγράψεις το λογαριασμό σου, αρκεί να μην έχουν πρόσβαση άλλοι χρήστες σ'αυτά, για 3 μήνες.Κι εσύ ανησυχείς για ένα ευκόλως αντικαταστήσιμο mail; :PΝα κι ένα κομμάτι από το Privacy Policy του Facebook:5. How We Use Your InformationTo serve personalized anstreividg to you. [...] Even though we do not share your information with advertisers without your consent, when you click on or otherwise interact with an advertisement there is a possibility that the advertiser may place a cookie in your browser and note that it meets the criteria they selected. (κοινώς σ'αυτή την περίπτωση το Facebook δε φέρει ευθύνη να σε προστατέψει).

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