What is the principle of a pinhole camera?
State three charateristics of the image formed in the pinhole camera .
Show a diagram.
A pinhole camera is the most simple form of photography and requires practically no knowledge of photography to build a pinhole camera and capture an image using it.
The basic principle behind a pinhole camera is the light enters through the pinhole at the front of the container (eg. a shoebox) travels through the light proof box and hits the photographic paper at the back of the box. The paper reacts to the light and where the light falls it is exposed (dark) and where there is no light the paper remains light. As you will be able to see after the image has been developed; the image produced will be a negative of the actual image. The image will also be upside-down due to the way in which the light enters the box.
Then all that remains is to develop the photographic paper as you would normally. You will not see anything until you start to develop the paper. The paper will still appear white.
- Light only travels in straight lines,
- The box will need to be light proof apart from the pinhole at the front,
- The pinhole cannot be too small, it can quite easily be too large,
- Only place the paper in the box and remove it from the box in a darkroom.
- Anything can be turned into a pinhole camera! Even rooms...
- An old shoebox works well, as does a film canister.
- Use black and white paper, it is easier to develop and far simpler to start with. Maybe experiment with colour afterwards.
- You will need to use trial and error to find the correct exposure time.
eg, if the image appears too dark decrease the exposure time, if it appears too light increase the exposure time.
characteristics of the image will be that its inverted .
The image created by a pinhole camera has certain characteristics which we won't find in classical lens photography. Since the process entails a central projection, the images in the pinhole camera are rendered in ideal perspective.
Another special characteristic is the infinite depth of field which, in a single photograph, allows objects to be captured with equal sharpness whether they are very close up or far away.
The pinhole camera takes in an extremely wide angle. The rays of light, however, take much longer to reach the edges of the negative than the centre, thus the picture is less exposed along the edges and therefore darkens.