How a camera works

Have you ever wondered what makes that iphone camera of yours works so well? Have you ever wondered the differences between todays digital cameras and the old film SLR's used by our parents and grandparents? In this blog post we are going to tackle the science and early history behind how the camera actually does what it does!

The first thing to know is that light moves in straight lines. We see this all the time, it is not that revolutionary of an observation. Think of light passing through an old vintage keyhole with a light on the other side because you know, that happens all the time....

Now as far back as 400BC, the founder of Mohism, Mo-ti is attributed with the first observation of what happens when light is forced through a pinhole. It is a really weird phenomenon which makes not only a camera, but your visual perception possible.  He observed that in a dark room, if you only allow light to enter through one small hole or "aperture" whatever you would see looking out through the hole, is actually projected onto the opposite wall, upside down. 
This physical property of light was first called the Camera Obscura. Imagine you are standing in a box, picture that, whatever kind of box you want provided it is 100% sealed from light.  It is pretty dark and scary in that box isn't it? We better let some light in....

If you were to take a knife or needle or whatever your preferred poking instrument is... If you were to make a small hole on one side of the box you would be forcing light to travel into that box through a straight line. Now turn around and face the wall opposite the hole....  If your box was located in the Roman forum, you would probably see something that looks like this.

CO-Roman-Forum.jpg

Pretty cool right? It is because of this weird property of light which makes photography possible at all. This is also how your eye works. Your pupil acts like a pinhole in a dark room. You can turn your room into a Camera Obscura like the one shown above. You can also go visit some which are tourist attractions on the West coast (1450 Ocean Ave, Santa Monica, CA 90401) and East coast (Front Street, Mitchell Park, Greenport, NY11944.)

Now if we knew this in 400BC, why did it take until the 19th century to take the first photo? Well! The trick wasn't getting the image on the wall, it was printing the image and making it permanent. The first person to figure this out was Joseph Nicéphore Niépce in 1826 or 1827. He took a photo from his window which looks over his estate. Back in the day, only people wealthy enough to have free time and funds to purchase chemistry sets made photographs.  It was thought of as an interesting hobby rather than a form of art.

Now in order to get this image, he coated a pewter plate with a solution of bitumen he had previously experimented with. He placed it in the pinhole box (camera) and let the light hit the plate for eight hours, hardening the solution where it was touched by light. After exposing the plate, he rinsed it with lavender oil and white petroleum which washed away the bitumen that had not hardened during the eight hour exposure.

Everything from this point up to the advent of digital cameras has been a refining of this concept and process. Different chemicals were used, lenses were added to the pinhole light-boxes, and people sued each other over copyrights in an attempt to make a quick buck. The pewter plate would turn into metal tins, then glass plates, and eventually film.

It wasn't long before George Eastman's Kodak company brought a refined process to the public on an unprecedented scale. Using light weight film as oppose to heavy glass plates, they sold small film cameras which could be bought, sent to Kodak where they would be processed and printed, and sent back to the customer. Anyone born before 1995 remembers taking their photos on the little yellow kodak cameras and waiting a week to get their film developed. 

Throughout the 20th century, most photographs you see where gelatin silver prints. These were the modern film SLR cameras used by Ansel Adams, Yousuf Karsh, and even Anne Leibowitz up until digital became the norm. Think about all the old tv shows which show a young scrappy photojournalist who converted a bathroom into their darkroom. Now a digital camera works exactly like a film camera with one important difference...

Instead of film strip sitting on the back wall of our special box, a digital camera has a sensor. I wont go into the detailed process of building it, you can read about it here. But the spoiler is that Steven Sasson, a 24 year old working at Kodak, figured out how to use a Charged Coupling Device (C.C.D.) to capture an image. Instead of physically burning the image onto a light sensitive film, it is burning the image into an electronic signal through the light sensitive CCD panel.

Further and further refinement through innovations of the 21st century have led us to where we are now. Everyone these days has a camera built into their phone. The technology is only going to get better moving forward as it has been for the last century and a half.

Now a days everyone is a photographer. I hope with this blog, we can move forward by making everyone a better photographer. If you are interested in learning more about your camera or photography in general, email me or comment below!


Sources:

http://www.obscurajournal.com/history.php

http://www.hrc.utexas.edu/exhibitions/permanent/firstphotograph/process/#top