Building a Moustrap Camera

This year marks the 175th anniversary of photography. One of photography's inventors, William Fox Talbot, used various small cameras to record his photographic studies.

William Henry Fox Talbot, by John Moffat, 1864

From Heilbrunn timeline of art history:

As his chemistry improved, Talbot returned to his original idea of photographic images made in a camera. During the "brilliant summer of 1835," he took full advantage of the unusually abundant sunshine and placed pieces of sensitized photogenic drawing paper in miniature cameras—"mouse traps," his wife called them—set around the grounds to record the silhouette of Lacock Abbey's animated roofline and trees. The pictures, Talbot wrote, "without great stretch of the imagination might be supposed to be the work of some Lilliputian artist."

Mr. Talbot's inventiveness was the inspiration to create a mousetrap camera of my own. I contacted Roger Watson, curator of the Fox Talbot Museum. Mr. Watson helped explain how to make these cameras: 

"...find a focal length and build a box around it. Talbot used a simple meniscus lens (flat on one side and curved on the other)... Talbot had almost 80 different cameras in all different sizes so anything you make will be close to the size of one of these cameras."

I've built a few cameras here and there, and have a tackle box full of camera building materials. Luckily I saved an old meniscus lens from a broken box camera, and this would be the lens I would build my camera around. The lens is about 18mm across, and with the help of a rubber washer and a piece of coiled wire, it is held snugly in place inside a piece of copper 3/4 inch water pipe (left over from a plumbing repair).

I still had no idea what focal length this lens would be. I focused the lens on the window across the room, and as it drew a faint image into focus on the wall I measured that distance with a ruler.  It was somewhere around 3-4 inches in focal length.

I made a rough box out of foam core and used wax paper as a focusing screen. After playing around with this for a bit, and focusing it on different objects around the house, I decided to build a little mousetrap camera. With the lens between 3-4 inches in focal length,  I built the camera 3 inches in height and width, and 3.5 inches in depth. The copper pipe/lens assembly is held with pressure at the front  of the camera,  and can be pushed and pulled in and out to aid in focusing.

A view through my small mousetrap camera, showing the lens assembly.

 Talbot used a cork on the front of his cameras, and he would peer through the front of the camera to see what was in focus, and then re-cork the camera before loading it with sensitive paper. I found this to be rather awkward, so I took a page from modern cameras and used some wax paper to make a crude focusing screen. I could focus the camera outside and set the lens, and then return to the darkroom and load it with sensitized paper.

This is my little mousetrap camera built out of black foam core and duct tape. The waxed paper focusing screen (right) snaps in the back of the camera to focus the image.

A view of the trees across my yard through my little mousetrap camera. Like all view cameras the image is upside down and backwards on the focusing screen.

Taking a photograph is a multi-step process. First the camera is taken outside and the focusing screen is used to frame up the subject. The lens is pushed and pulled until the image is in focus. The camera then goes into the darkroom and a piece of photo sensitive paper is placed and sealed inside the camera. The camera is taken back outside and the image is made. Finally, the camera returns to the darkroom, the paper removed and developed.

I used sticks to outline my camera. This way I could tell exactly where the camera should go after focusing and then later returning with the camera loaded with photo sensitive paper.

Here is the darkroom, complete with coffee-based Cafenol developer (left). Finished images are sitting in the fixer tray (right).

The 2.5 inch square paper negatives hang out to dry.

 Talbot used special sensitized drawing paper he made himself. I had the luxury to use regular enlarging paper in my cameras to make negatives.

After the negatives were developed and dried, I scanned the negatives and inverted them in the digital darkroom to make positive images. Overall I was very pleased with the results. The negatives were a little flat and lacked some contrast. Luckily that could be fixed with the help of Photoshop. The lens was never intended to be shot wide open, it had a much smaller stop inside so that only the "sweet spot" in the center was used, and the outer corners with swirls and light fall off were never seen. In my camera, the lens is used almost wide open, so you can see all the effects of a simple meniscus lens when it is used to make photographs. Images were all about three seconds in exposure, and developed for about 1.5 minutes in the Cafenol developer.

You can see the light fall off in the corners, and the out of focus areas o the outside of the frame.

The lens recorded the trees, grass, and the bank of leftover snow quite nicely.

I tried a macro type photo through a small grape arbor looking out towards my garden. The lens was pulled almost all the way forward to focus.

So what is next? Now that I am comfortable with the focal length and design, I would like to build my mousetrap camera out of wood instead of foam core and duct tape. I would also like to learn Mr. Talbot's sensitized paper formula, and make more images of course! I can't wait for the weather to get warmer, so I can get out in the garage and start building my camera, and making more images.