Camera Obscura

I have wanted to make a camera obscura for years, but could never quite figure out how to pull it off until today.

What is a camera obscura? It’s simply a dark box or a room with a small hole on one wall to allow light in. You can see a projected image of the outside of the box on the wall opposit of the hole. The camera obscura predates photographic cameras by many centuries and led to their invention.


Whilest learning italian, I thought it was odd that their word for ‘room’ was ‘camera’. At the time I thought there must be a reason for it, but had no idea that the first ‘camaeras’ were ‘rooms’.

Wikipedia has the nitty gritty if you wonder exactly how they work:

Images produced by a camera obscura seem to be far apart, but I do see them on the web occassionally and they can be very striking. Which keeps me thinking I’d like to do one some day.

My house faces a little city park, and I’ve always thought it would be cool to turn my living room into a camera obscura, but there are big windows in the living room and connected dining room, side windows in both rooms, and hallways all allowing light in that would have to be blocked off. That would be way too much work for any quick photo project which is all I’m willing to do.

Cameras obscura (or camera obscuras?) popped into my head again today as I looked out the living room at the park in its fall foilage. But, I was still too lazy to do anything about it. Then I happened to go upstairs and look out the window. Here has the same view, but in a small room with a single window that could be easily blacked out.

So I set out to build my camera obscura. OK, build may be too strong a word. This is a VERY simple project for the most part. You simply block ALL light out of the room. I used card board, but you can also cover all windows with aluminum foil if you have to cover really big windows. As I discovered, even devices with a single LED will end up causing problems. Turn out the lights and look for every light leak and get rid of it.

Let me insert a personal testamononial for gaffer’s tape here. If you have never heard of it, gaffer’s tape is like duct tape, but made of cloth and while very sticky, can be removed without leaving any gunk behind. I have used it for many years largely for photography, but any other time I need to stick something to a wall or window or something else I don’t want damaged. It’s not cheap but far better than duct tape for projects like this. You can find it on amazon, of course!

Next cut a circular hole about 3″ in diameter in the material covering the window. Finally, cut a 1″ hole in some aluminum foil (as perfectly round as you can) and tape that over the 3″ hole. Get used to the dark and you will see the outside image, inverted on your wall. OK, you probably will only see it in black and white because it is kind of dim, but you will definitely see it.

Here is what my camera obscura looks like:


The next step is to photograph it. That is the tricky part. It will take a LONG exposure. Using 5.6f and 1600 ISO, it took a 30 sec exposure to get a good image using the 1″ hole. You will have to just play around until you get a good exposure at a high ISO. Once you have it, reduce the ISO to the value you want and double the time the same amount (reducing 1600 to 400 halves it twice, so the time must be doubled twice or 240 seconds).

The good thing about a 1″ hole is it lets in a fair amount of light. The downside is the image is not as sharp as it could be. Now try a 1/4″ hole. The image is fainter, but clearly sharper.

My final result used a 1/4″ hole, ISO 200, F4.5, with a 32 minute exposure.

Here is the final result:


Unless you like spending a lot of time in a dark room alone, you may also want to come up with a way to remotely fire the camera. Last year I built a cable to connect my camera shutter to my pocketwizard (normally used to fire remote flashes). I used that to trigger the camera from outside of the room.

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1 Response to Camera Obscura

  1. Pingback: And… and I’m… I’m real… | Gini Lawson

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