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| For reference: View from bedroom window using DSLR |
My research had suggested that the quality of the image was a trade off between the image brightness and the image sharpness. A small aperture was required in order to get a sharp image but that would impact upon the brightness of the image. This was obviously something that I would have to work with as the experiment progressed.
To black out the windows I decided to use duct tape
and black bin liners. With hindsight I should have used thick cardboard as the
bin liners are too thin and let a lot of light through. To make them light
tight I had to fold them over many times. The hardest part of the entire
project was making the room light tight! I spent numerous hours sticking bits
of cardboard and bin liners to the window and even then the room was never
entirely dark.
The
aperture was made by piercing the cardboard with a pencil. Not very scientific!
but this part was always going to be a bit of guesswork. The aperture was
approximately ¼” in diameter and rather rough round the edges.
In an attempt to cover all the light leaks I looked around
the room to see where they were coming from and repaired them as well as I
could. Then I pierced the cardboard for the aperture and I noticed that there
was a very bright circular shape being cast onto the bed and also a strange
horizontal line that I hadn’t seen before.
In the past I would have thought the bright light was
merely the light that was shining through the hole but through
my research I decided that the circular shape was the sun in the sky. I tried
to track down the source of the strange line as I thought it was coming from a light
leak somewhere and I eventually deducted that the only way to prevent the
strange horizontal line from appearing was to cover up the aperture. Then it
struck me that this might be the first signs of an image. It was too feint for
me to make it out properly so I tried to make the room even darker than it
already was.
I had read that a feint picture can be made to
appear brighter by placing a white card in front of the aperture. To my
amazement, this made a massive difference and the familiar view from my bedroom
window appeared in front of me. It had evidently worked!
I took a series of photographs using a digital
camera so I could evidence the experiment which I have shown.
The Next day...
With a full moon imminent and the sky forecast to be
clear, I had wanted to see if I could see a nightscape through my camera
obscura. I left the blackout up in the window and before I went to bed I made
the aperture larger as there wouldn’t be as much available light. I also moved
it higher up as I knew that the sun had been cast too low down for me to be
able to see it at night.
I was disappointed to see that I couldn’t see
anything at all except for the moon itself which was rather obvious in my
otherwise dark bedroom.
When I awoke the next morning I was surprised to see
that the reflections on my wall were even more evident than they had been the
previous day. The effects are supposed to be more evident when the sun is
shining brightly, but on this particular day the sky was overcast and the sun
wasn’t visible.
My results suggest that the aperture I used on the
previous day wasn’t as big as it should have been.
Inside my Camera Obscura:
This photograph shows me laid in bed with a projected image of the outside world on my bedroom wall
All photographs copyright Rob Smith
