Haunty is a history buff who enjoys reading and writing about ancient history and cultures from around the world.
Leonardo da Vinci's Study of Optics
Leonardo da Vinci was a painter, draughtsman, engineer, scientist, theorist, sculptor, and architect of the High Renaissance. Possessing a brilliant mind that may have been able to perceive in both two-dimensional and three-dimensional vision, the Italian polymath contributed countless innovations that changed the world.
One of the fields that most intrigued Leonardo da Vinci was optics—the science behind how the human eye works. In his 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 believed this was wrong because it would take too long for such a ray to leave the eye, bounce off of something and then return to the eye.
To explain his dissent, 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, they would require a month to return.
Though this estimate on the sun's distance from the Earth was pretty far off (Da Vinci believed it was 4,000 miles away when, in reality, it’s 93 million miles away), his objection to sight rays proved correct.
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.
Da Vinci dissected human eyes to study them, boiling them in water until the whites hardened and could be easily sliced open. He used his observations to develop a projector, bifocals, and even came up with the idea for contact lenses, though he never actually made them.
Da Vinci also conceived of a gigantic lens to harness solar energy for the dyeing and tanning industry. Some contemporary historians believe that he came up with the concept of the telescope long before Hans Lippershey, the Dutchman who is credited with its invention in 1608.
“...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.”
...Here the figures, here the colors, here all the images of every part of the universe are contracted to a point. O what a point is so marvelous!
— Leonardo da Vinci
Leonardo da Vinci's Camera Obscura
The camera obscura, which translates to 'dark chamber,' was one of the most interesting optical inventions Leonardo worked with. He was not the first person to use one, but he was first to notice the similarity between the way a camera obscura worked and the way the human eye functioned.
How the Camera Obscura Worked
A camera obscura is merely a dark box (or even a very dark room) with a tiny hole that admits light. Directly across from the hole, the image from the outside world is projected upside down onto a piece of light-sensitive material.
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 reversed and inverted. This was written about by the Chinese philosopher, Mozi (470 to 390 BCE), who described the space in which you see the images as a ‘treasure room.’ Aristotle also wrote about the phenomenon in the 4th century.
But it wasn't until 1490 that Leonardo fully fleshed out the camera obscura in his 1,286-page Codex Atlanticus. Written in Latin, this 12-volume work described the mechanics of the device:
"If the facade of a building, or a place, or a landscape is illuminated by the sun and a small hole is drilled in the wall of a room in a building facing this, which is not directly lighted by the sun, then all objects illuminated by the sun will send their images through this aperture and will appear, upside down, on the wall facing the hole. You will catch these pictures on a piece of white paper, which placed vertically in the room not far from that opening, and you will see all the above-mentioned objects on this paper in their natural shapes or colors, but they will appear smaller and upside down, on account of crossing of the rays at that aperture. If these pictures originate from a place that is illuminated by the sun, they will appear colored on the paper exactly as they are. The paper should be very thin and must be viewed from the back."
How the Human Eye Works
Da Vinci noticed that the camera obscura sees exactly the way the human eye sees: Light reflects off the surface of the object and travels through a small opening on the surface of the eye (your pupil), and the image ends up flipped upside down. Both the human eye and the camera obscura have openings, a biconvex lens that refracts light, and a surface (your retina) on which an image is created.
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!
From Camera Obscura to Photographs
In spite of its name, a camera obscura isn't really a camera in the way we know and use them today. It has no ability to take a photograph. That functionality wouldn't arise for hundreds of years.
After Da Vinci, 15th century artists used the camera obscura as a drawing tool. Some art historians believe the 17th-century Dutch master Johannes Vermeer used a camera obscura to help trace the drawings underlying his paintings.
The Pinhole Camera
In the 1800s, we see the earliest iteration of a photographic camera with the pinhole camera, a term coined by the Scottish scientist, Sir David Brewster. Like the camera obscura, pinhole cameras were just boxes with tiny holes, but these contraptions were able to offer more than just a mirage—they could project an image onto paper that contained photographic emulsions, thus capturing a permanent photographic impression.
Thomas Edison experimented with pinhole cameras, but reportedly didn't like the look of the images.
Pinhole cameras weren't long for history, but they served as a link between the camera obscura and the first real photographs.
The First Photographs: Joseph Nicephore Niepce, 1827
The first real photos were taken by a French chemist named Joseph Nicephore Niepce in 1827. Niepce set up a camera obscura and placed a polished pewter plate coated with a type of asphalt called bitumen of Judea, which can be used as an organic pigment.
After eight 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. 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.
Leonardo da Vinci's Contribution in Photography
Leonardo da Vinci devoted many years to his research of the camera obscura, producing hundreds of diagrams and writing thousands of pages. Strangely, Da Vinci decided to encrypt much of his notes in mirror writing, which delayed their translation for two centuries.
Fortunately, we can read and appreciate his and others' scientific discoveries on the camera obscura and optics, which helped give birth to the world of ubiquitous camera technology we live in today.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
Devon Bilski on February 23, 2018:
This assignment is really interesting, makes me have a different perspective on photography as a whole and a new appreciation for Leonardo da Vinci.
alex ramos on August 23, 2017:
didnt learn anything from this
Emma on February 27, 2017:
Very, very, VERy interesting I learned a lot from this website for my school classes!!
BAL on February 27, 2014:
Vanderleelie on July 10, 2012:
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.
Anne Harrison from Australia on January 20, 2012:
A great hub - the side boxes with extra details were an excellent idea. Voted up, looking forward to more.
lisa.bom on January 19, 2012:
Very interesting! I really enjoyed reading this.