JPG: Stories: How To: Camera Obscura

How To

Camera Obscura

By Kyleigh Digregorio

17 Sep 2008

This summer, photography class has been full of cool experimentation. Here's the latest.

Camera obscura. No, not the band. A camera obscura room is a dark chamber ("camera obscura" literally means "dark room" in Latin) which functions exactly like a pinhole camera, and is one of the earliest methods of photography. When accomplished, the result is an image from outside that is projected onto all surfaces of the room. Here's what you need:

1. A small room with one window (unless you plan to take the time to cover all other windows)

2. The view from the window should ideally be of scenery (a neighbors house, city street, backyard, your town, trees, garden, ect. anything that ISN'T just a brick wall or a blank side of a house)

3. Black posterboard, felt, sheets, etc. Anything that can be used to effectively cover the window, letting as little light through as possible.

4. Small postcard-sized pieces of thick black paper or posterboard. These will be used to make apertures.

5. Masking tape or duct tape.

6. A white piece of poster board (optional).

7. If you plan to take pictures of the image being cast on the walls you will need a tripod for your camera, the room will be very dark and the shutter speed will be much lower.

8. Sunlight. You must do this during the daytime so your "make-shift" lens can capture light from outside

The first thing you need to do is block all light sources from the room. Cover the windows COMPLETELY with the black poster board, felt, or sheets. For effectiveness, use masking tape all around the perimeter of the cover. Best results will come from total darkness.

Next, make a small hole in the center of one of the postcard-sized pieces of black paper. Use a hole-punch or something a bit smaller if you have it. This will be your aperture. The image and clarity does change depending on the size of the aperture, so this is where the experimentation comes in. Try different sized holes on the different pieces of paper, and remember which ones worked best.

Then, cut a rectangle into the material that is covering the window. The rectangle should be about the same shape as the postcard-sized aperture but just a little bit smaller. When this is done, use the masking tape again to tape the aperture over top the cut rectangle, so the only way to see through the window is through the tiny hole.

Now, block up any light coming from underneath the door and turn off any lamps that were on inside of the room.

Once all light is cut from the room, light from outside should filter in through the small hole on the window to produce an upside-down image all over the room. To see the image more easily, you can hold up a white poster board or sheet a few feet from the window, in front of the hole, and the picture will be caught on it.

Now, an explanation on how this works.

First of all, the image that you see inside your camera obscura is upside-down because the room is literally acting as a camera. Light travels in a straight line, and when part of it is caught through a tiny hole, it reforms on the other side of the hole to produce an upside-down replica of the true image. Everything that is seen by the human eye emits a wavelength of light, giving us color, and since every point outside of the window is filtering beams of light through the hole, an image can be seen on the wall and/or white poster board. This is the same way a pinhole camera works.

This is a fun an easy project that will not only let you feel as if you are inside of a camera, but will also give you a new understanding of the inner workings of pinhole cameras, lenses, light, and perception.

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