"To make large-format digital pinhole images, I designed and built http://www.thingiverse.com/thing:1515060 -- a 3D-printed 150mm pinhole obscura that mounts an $80 Canon PowerShot ELPH 115 IS. The Canon is programmed using CHDK to capture an HDR sequence. This is the pond nearest my house."
"Materials cost for the pinhole obscura was about $5 + the $80 Canon ELPH 115 IS; the design is free, so you can make your own. The texture is from the tracing paper used as the obscura screen. The 5-shot HDR took about 30s on a tripod, merged and scaled to 700-pixel width using GIMP."