How Does a Pinhole Camera Work ?
Almost every child has made a simple pinhole camera in elementary school or at some other time during their youth. In basic terms, a pinhole camera reduces the idea of taking photos to its simplest terms. The key is to make sure that the only light that enters the camera comes through that tiny hole. Film has to be placed correctly in the box so that the small amount of light strikes the surface of the film. A chemical compound on the film changes when exposed to light, producing an image.
The reason this is called a pinhole camera is that the hole has to be extremely small. Making this with a pin produces a hole that is easier to focus onto the film surface. Sharper images are produced with a smaller hole. If the hole is too large the image won’t be sharp and it won’t be possible to focus the light onto the film surface accurately.
Some light passes through the pinhole from every object or surface that could be seen through the pinhole from inside the box. A shoe box works well but some people have found that an oatmeal box works extremely well. The light passes through the small hole. The film secures a focused image of the object or scene at which you point the camera. With a more complex camera, the lens helps reduce the light and focus it intensely. With a pinhole camera you may have to keep the pinhole uncovered for a longer time because the amount of light getting in is so small.
Rather than having a quick-action shutter, as on a complex camera, the pinhole can be covered and uncovered manually. Some people use a sheet of dark construction paper or a light, solid object to cover the pinhole when the camera is not in use. Some people have even used pinhole cameras to track movement of the sun or to work with something that looks better with long exposure. A simple picture can be taken by uncovering the pinhole for about five seconds. Pinhole cameras can also be used to display images directly on another surface for immediate viewing. People have used these cameras to observe a solar eclipse, for example. A lens can also be used with a pinhole camera in certain situations.
Some more complex pinhole cameras provide for moving the film forward and backward to get a wide-angle view or a narrow view, depending on what the subject is. It’s possible to use a small, traditional camera as by substituting a pinhole setup for the lens portion.
Category: Technology