• Take a box with a side taken out. This will be for observation.
• Now, cut a small hole in the center of the side of the box, adjacent to the observation.
• Shine a flashlight into the hole and observe what happens when you move the light around.

What happened inside the box?

The light will always shine onto a point in the box, directly opposite from where you are shining the light from. Light travels in a straight line. It’s a concept most anyone can grasp, and applies to any light source outside the box, including scenery being inverted inside a room, through a hole of the right proportions.

I will be discussing the camera obscura...where it came from and how it takes its place in the history of the camera.

What Exactly Is a Camera Obscura?

Initially, this was simply a darkened chamber with a vaulted ceiling. The term, camera, simply meant such a room, though the term obscura described this room as a dark one. It came to mean such a room with a tiny hole in one wall, allowing light to pass to the opposing wall.

In modern times, it refers absolutely to modern cameras with the ‘obscura’ dropped from the term during the 19th c.

What is the nature of image projection?

Image projection refers to the transferring of a scene to a reflective representation of the scene onto a medium where it can be captured, either manually or by photographic process. This happens exactly as described above.

The naturally-occurring phenomenon of light projection sparked the attention of folks very early on in China and Greece, alas, most likely everywhere, but it is in these two countries where visionaries began experimenting with it.

Even naturally-occurring spectacles like this caused folks, frightened by them, to believe they were supernatural, miraculous, even the manifestation of an oracle.

Early Applications of Projection

It was soon discovered that a hole, placed in a darkened room produced an upside-down and inverted image of the scene directly in front of the hole. The distance to the wall opposite the hole was an important variable in obtaining a sharp representation of the scene outside on the wall inside.

It was found that the smaller the hole, the sharper the image became, though the darker the room and fainter the image on the back wall would become.

This faint image was taken advantage of early on. With the hole too small to be detected by folks in the room and the circular projection from the hole on the wall could be made so dim that it could not be readily detected, especially during the time folks' eyes were adjusting to the darkness.

Outside, in front of the pinhole, there were actors with bright shiny things would dance around. The results on folks inside were spell-bounding!

Eventually innovation led the way to image capture using of mirrors, spawning the development of the magic lantern.

To Recap:

• The camera obscura marks the beginning episode in the history of the camera.
• Light passing through a pinhole in a box, hitting the wall opposite the hole always produces an inverted and upside-down copy of whatever is being reflected from the outside.
• In its basic meaning, the term, camera (with the adjective, obscura) is a darkened [vaulted] chamber, later, simply a box, with an aperture to let in light. The earliest meaning of the term did not refer to the same with a hole in the wall.
• Projection refers to the transferring of a light source to a medium, where it can be processed.
• The camera obscura was used to enthrall (or trick) folks who entered the room. Later, after boxed versions of the vaulted room were perfected.

Without the laws of nature, regarding light, making the camera obscura technique possible, not even latest generation of cameras today would exist.