The Pinhole camera or Camera obscura is the most primitive camera, invented about a thousand years ago. It was a simple device, basically a light-proof box, big enough to sit inside, with a small hole to let light enter and project an image onto the opposite wall. At first, recording of the image was done by manually tracing the projected image. A less manual method of recording was not discovered for another 600 years.
smaller the hole the clearer the picture. My first attempt at a hole was too big, the pictures were quite blurry. The cardboard was too thick to make a good, small, clean-cut hole all the way through, so I removed a larger piece of the cardboard and then covered the space with 
aluminum foil, since it's very thin and blocks 100% of light. Then, with the cardboard laying flat on a table, stuck the pin in again. This way I got a hole that was only the size of the tip of the pin. The pictures are still a bit blurry, but good enough, I guess. The depth of view seems to be infinite, there's never a need to worry about focus. Objects near and far look the same. Due to the small amount of light, all these pictures needed a 20 - 30 second exposure. Below is the first attempt:
So I gave it a try. Making the image isn't hard, but trying to see the depth in the pictures without special equipment, like a View-Master, is a different story. It is possible, however, with some practice. The trick is to get one of your eyes to look at one side while the other is looking at the other side. I'm not really sure how to explain how to do this. Try looking between the two images and slowly crossing your eyes. I find that everything goes blurry and then slowly, the two images drift together until it looks like there's three images. Now try to focus your vision on the center image. It takes some time to get use to. It's a similar technique to view Magic Eye images.
