Camera Obscura and Pinhole Photography

Before the Easter break we were introduced to some things that will we be looking at in further detail next term. Two of these things being the camera obscura and pinhole photography.

Some basic knowledge related to both of these are as follows:

  • light travels in straight lines – hence the inverted image
  • how will altering the size of the hole alter the image?
  • The smaller the hole, the sharper the image, and a longer exposing time is going to be needed.
  • The bigger the hole, the image loses its sharpness, more light is able to get through meaning you are looking at a shorter exposure. However you really want to get that hole as small as possible to get the best results.

To show how quick and easy it is to make a pinhole, we were shown a video during our lecture.

You want to make sure your container is completely light proof, if not you are going to get leaked light across your images, which is not what you want.

If you use a tin such as beer cans, or quality street tins etc, you really want to paint the inside of your tin black, as when light travels through your pinhole, the shiny tins then reflects, which then bounces the light in every direction, this will cause you to only get a small amount of the print and will most likely fog the paper.

BluTack is an extremely useful element when using your pinhole, if you have several aperture holes in your object you can easily cover it over with BluTack. Or if you need to use your tripod, place BluTack on the top to make it nice and sturdy for your exposure.

It is best to use multigrain paper for pinhole photography.

Depending on your focal length of your pinhole, exposure times can vary, the further away your paper/film is from your aperture, it takes longer for the light to reach the paper, meaning you will need to expose it for longer.

In general, outside exposures in daylight are roughly 10-30 seconds but again it depends on how bright the daylight is. The brighter it outside the less time it will need exposing, but also consider your focal length.

Indoor exposures are much longer, it is best to start at the 3-5 minute mark, but you may find it could easily be a lot more. It could even reach to an hour exposure.

The longer the box or object you are using for the pinhole, it will change the zoom of your final outcome, so it becomes more of a telephoto lens.

The smaller the box length, it becomes more of a wide angle photograph.

When you make your hole for your aperture, make sure to file it down as light is limited when it comes to angles, filing it down allows it not to be restrained. Also if you are using a tin and you have rigid edges it is likely light could reflect and ruin your image. Filing down all depends on the material you are using.

If it is the first time with using a pinhole, it might be a good idea to keep a log of your exposures so you become more familiar with your own camera, making it easier to use in the future.


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