For WPPD 2011 we got creative. We built up a box from odds & ends of scrap around the workshop, but designed to work with a 4x5 filmholder. For 2011 we started with print paper to make negatives, but ended up also using film as well.

The camera is a wooden box, large surfaces made of 1/4 inch birch plywood over a frame of white pine. The box has three sides extended in the back and one side flush to accommodate a standard 4x5 filmholder. Rubber bands over wood pegs keep it against the gasketed back. The front edges of the side pieces extend past the front frame such that the front panel comes out flush. The panel is screwed in over a light seal and could be removed to try other gadgets on the front.

The Box 4x5 Pinhole camera was used for WPPD 2011, WPPD 2012 and WPPD 2013.

The final parameters:
Pinhole to film distance ("focal length"): 2.44 inches (62 mm)
Exposure Mask Area: 3.9 x 4.75 inches (100 x 120 mm) Diagonal: 6.15 inches (156 mm)
Diagonal Field of View: 103º
Pinhole diameter: 0.012 inches (0.30 mm); about f/210
Pinhole Constant: 1.65
f/22 Exp Multiplier: 88
Weight: 550g (~1.22 lb) with filmholder