Camera Obscura - The First Camera
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When many people think of cameras they think of photographs. The first cameras however were unable to record light in any way. They had much in common with more recent pinhole cameras except that the viewer had to be inside of the camera to view the image. Furthermore the image would not last once the door had been opened or the hole sealed. In fact the image formed by a true camera obscura was more akin to a reflection than a modern photograph. Early scientists and natural philosophers observed the same phenomena occurring. If a small hole was formed in the wall of a dark room ("camera obscura" literally means "dark room") a very curious occurrence would manifest. Rather than the room being flooded with light an image would be projected onto the wall or floor of the room opposite the hole. This image was the same scene as could be found outside of the pinhole except reversed in orientation. In other words the outside world would suddenly appear inside of the room - upside down. This was first observed by a Chinese philosopher Mo-Ti in the 5th century BC. Less than a hundred years later the Greek philosopher Aristotle observed and recorded the same phenomena. Neither Mo-Ti nor Aristotle were able to explain what caused this strange projection and it wasnt until the 10th century AD when Arabian scientist Abu Ali Al-Hasan Ibn al-Haytham performed experiments using five lanterns and a camera obscura that the world gained a more clear understanding as to the how and why. Al-Hasan was able to accurately describe the phenomena mathematically. When light passes through a small opening an interesting thing happens. While it is technically true that light moves as a wave it can also be said that light travels in straight lines. When light strikes a small opening most of the light is filtered out. Light from the top of the object will pass through the hole only if it is angled downwards and likewise light from the bottom of the object will only pass through if it is angled upwards. As a result of these limitations the inverted image is able to form.
This basic design has been modified many times over the centuries. Innovative changes include inserting a lens into the pinhole opening to magnify the light or inserting a series of mirrors and lenses to redirect the light in a different direction and therefore project it onto a different angled surface. Even modern camera enclosures are technically a form of camera obscura because they are a darkened chamber with an opening which allows light to be projected onto a specific surface (film or a digital sensor). Advancements in photographic technology have lead away from the popularity or necessity for large, room sized camera obscura. And yet the camera obscura is regaining certain popularity. Perhaps out of nostalgia for the classic feel of old photographs many people have expressed an interest in camera obscura and they can now be found in museums throughout the country. One particularly stunning example was built in July 2006 when a three story high airplane hangar was converted into the worlds largest pinhole camera. The camera was used with a huge sheet of photosensitive paper to capture the image but the building itself was a true camera obscura.
Further Reading:
The Magic Mirror of Life: an appreciation of the camera obscura |
