Camera Obscuras
A camera obscura, (Latin for 'Wow, look at that!) is a camera where, instead of capturing the image, it is experienced by the viewer. They go back to 400 BC when Mo Tzi in China used one to suss out that light travels in a straight line in the same way as arrows being fired. Clever guy! If you want to experience instant wonder, this is for you.
I have split this section into info using both use of holes and lenses explaining the various designs from small hand held devices to room obscuras and finally to fun designs which get me and my family into festivals (remember them?)
A quick word,,,,
This section is mainly videos and a few handouts. I am happy to give out further information on construction of these devices, especially if they are for educational use, however, some of my ideas have been taken and used for commercial and promotional motives so contact me first for more info.
Holes vs Lenses
Both of these can form an image and for obscuras have advantages and disadvantages depending upon what you want to build. The other thing you will need is dark.
Dark. The main way to experiment with light is to initially remove it so your container / room is completely blacked out.
There are two ways then to let the light in.
Pinholes cost nothing and project an image which is always in focus. The disadvantage is the image is quite dim so you need to view the image close to the hole or use a long exposure to view the image. Making the hole larger will make the image brighter but it will become increasingly less sharp.
Lenses give a far brighter image but require focusing. Sounds a bit complex but the way to work with lenses is to see what you have and construct around the lens. My book has oodles of information on this but as a rule of thumb you can usually make use of cheap reading glasses which come in a variety of focal lengths - strengths, and magnifying glasses.
Hand held obscuras
The Cream cracker (hole)
Work out when a partial solar eclipse will occur. Find a local primary school, hand out 250 cream crackers ('saltines' in the US) and a sheet of white paper. Get them to view the multi projection made by the holes in the cream crackers. Collect up the paper (the crackers disappear!)
The Cereal Box Obscura (lens)
Ultra simple, ultra cheap. I also call it the 'Actual reality headset'.
All you need is a cheap magnifying glass, a shower curtain some gaffer
tape and an appetite for 'Fruit and Fibre' cereal!
The Tube Obscura (hole)
Ultra simple, ultra cheap and a good excuse to eat a tube of pringles!
Makes use of the pinhole being close to the 'film plane'
If overcast view a light bulb or a close up of a computer screen
The Eyescura
An adapted laundry basket which enables people to see the world without a brain ( upside down). Great fun for all and a fave at many festivals. All you need is a cheap +3.5 pair of glasses, a shower curtain, some gaffer tape and a field of drunk people! Contact me for instructions, meanwhile here it is in action.
Drawing (Canaletto) Obscuras
Canaletto was one of the first painters to admit to using a camera obscura to assist with his paintings. Its very easy to get lost in the ability to draw from reality using an obscura. I built one specifically for TV but have frequently used it since. Contact me (or buy my book) for further information.
Larger Obscuras and installations.
Television Obscuras - The fastest live TV in the universe!
Add a lens and a shower curtain to an old tv dredged out of a river =
The Triclops
A three lens design constructed for the wonderful Womad festival kids area. A bit of a build but good fun
Australian Mission Control
Another design constructed for the wonderful Womad festival kids area to celebrate 50 years since the moon landings. One of my favorites!
Probably the easiest and most effective way of showing instant photon wonder to your family, your class or just yourself. See here for further info.
Further info with instructions on various designs of mine here
Visitable Obscuras
There are quite a few around (well around 15 in the UK) but I thought I would let you know my favorites.
The Clifton Observatory - Bristol, UK. The best in the world in my home town of Bristol. Contact me and I will guide you round if I have the time!
The Edinburgh Obscura - Wow what a place and a fine observatory at the top. Caller the world of illusions but well worth a ticket.
The Great Union Obscura - Douglas The Isle of Man. A fine example of what wealthy Victorians spent their money on. Amazing how it hasn't fallen down the cliff into the sea. The images it projects arent great but its worth a visit to see if it has survived!
Whagarai Obscura - The best Obscura in New Zealand build by the wonderful Di Stoppard. A labour of love and around 20 years from brain to ground. Lovely stuff.