Tracing Camera Prototype

The Exploratorium asked me to prototype a portable camera obscura for the new building to be used as a tool to make observations and draw the local landscape.  It is a very optically simple device consisting of a box with a lens mounted in front of a 45 degree mirror inside to flip the image right side up and a piece of glass on top onto which tracing paper can be placed to receive the image.     

Originally the tracing camera was mounted on a sturdy aluminum camera tripod, this proved usable but not stable enough to make complicated drawings easily. In trying to design the tripod to replace the aluminum one, I looked at a lot of heavy designs used for survey equipment.  The common thread between all these designs was the triangular multi-element legs.  As I wanted to avoid cutting 2 or 3 pieces precisely for each leg I decided to simply bend them together instead. To simulate how the plywood might behave I made the preliminary model with popsicle sticks to find out how much more rigid it was than a single element.  These legs afforded me a very stable platform to draw on which resisted shaking and twisting very well.

    

The Tracing camera in use at Pier 3 in San Francisco.

Here you can see the camera's three controls, the lens barrel is coarsely threaded and can be turned to focus the camera. The upper knob is a tilt lock and the lower is a pan lock. The lens barrel assembly is machined pvc pipe fitting and delrin.   

Paper holder tripod is a reduction of the original camera tripod, to make it lighter and more easily collapsable.

The legs, joint plate and desk top (the indentations for the pencils and sharpener) are made on a cnc router and the rest of the wooden parts were made by hand.

The cardboard shroud blocks ambient light from the front of the camera casting a shadow on the tracing paper making the image appear bright.

photo by Gayle Laird, Exploratorium

Drawing detail looking at downtown from Pier 3 in San Francisco.

Another drawing detail looking out at docked boats at Pier 3.