Petting Zoo: Tom Thumb

 

With images about 1cm square, this camera is currently the smallest member of my homemade fleet.

Specs 

This size was based on the available lens, about a 20mm f/2.8 scanned from a 110 pocket camera. I broke down a small hobby jewelry box for the wood. 

The plate holder is based on layers of cereal box cardboard to build up the dark slide unit (3 layers), the corner support layer, and the plate recess and lid rim (3 layers). The cloth-hinged rear closure sets the final depth of the plate holder. The ground glass holder has the same layout so as to build up the correct focal offset for the image plane.

The camera base has a tiny, proportionally sized tripod screw (10-32 thread as I recall). I then fashioned a bracket to adapt this thread to a standard 1/4"-20 tripod thread. This  bracket doubles as a display stand as seen here.

The lens unit happened to just fit inside a brass tube that is press-fitted into the front standard. The camera focus is based on the early "sliding box" principle.

To prepare a plate for an image, I have cut a business-card sized aluminum etching blank into 1 cm sized squares. A drop of collodion amply coats this tiny area. I fashioned a clip from Teflon-insulated wire to hold the plate for sensutizing and development. 

At this size, the cost of materials used is probably pennies per try. But the effort to get a good result is about 3 times more!