Wednesday, June 6, 2012

How to make a better pin-hole camera

Sleepy me wakes up today to see the web abuzz about the transit of Venus today. The one thing that alot of places talk about is how to view the transit, and one of the cheapest and easiest ways is using a pin-hole camera. The problem I have seen is that many people only have basic knowledge of pin-hole construction. Honestly if you have binoculars or a telescope there are many techniques that are easier than a pin hole camera so I would suggest using those. But a few simple tips for making pin hole cameras...(Finally a sciency topic which I am more qualied than most to talk about)
-Paint the inside of the box you are using black; help stops light leakage through thinner card and stops light bouncing around inside.
-Foil is not a great substance for making a pin hole out of, it's thin and when you stick the pin through it actually rips the foil rather than making a clean round hole. The objective is to make it as round a hole as possible to get the best image. The best results I have seen involve a thin piece of sheet metal, rather than poke a hole you hit it with a round metal stamp or punch that doesn't punch through but makes a small round bump in the metal. You then sand the bump with fine sandpaper to get a very round hole.
- Without a lens the light coming through the pin hole is very weak, so it needs to project into a dark or shaded area, the darker the better. Best result come from a traditional Camera Obscura; a darkened room with the pinhole letting light in. This is utterly impractical with something like the transit but we managed to turn a Photography darkroom into a massive Camera Obscura when I was in TAFE using the noticeboard pinhole in the door. (We also did it with a classroom and I have seen someone make a pinhole camera out of a PeakingDuck)
Just some tips, maybe too late but you never know...