Check out these Aluminium Shutters images:
Air photo 1
Image by hamoid
shadow > source
A slightly absurd technique was used to take this photo.
I bought a tiny battery powered security camera. This camera looked through the viewfinder of my reflex camera, and transmitted what it saw. Both cameras where on top of a 4 meter aluminium mast. I walked with it through a park. In my hand, a wireless TV receiver allowed me to see what my camera saw, and a wireless shutter let me take photos when the image in the TV was interesting.
Climbing a tree was probably much easier 
img_4518
Image by steevithak
Blue Nissan Versa reflecting the pinhole photographer
These were shot with a Canon 40D using aluminium foil over the lens mount. I poked a hole with a pin near what I hoped might be the center and started shooting. I cranked the ISO up to about 1200 and was able to use shutter speeds around 1/6 of sec.