Guide to Pinhole Photography
Pinhole photography is a technology to make photographs using lens-less camera. The lens is replaced by a tiny hole. When light passes through the hole, an inverted image is formed on the screen (negative). A can or a box that can hold light-sensitive photo paper or film can be fitted with a tiny hole to make photographic images.
Pinhole Photography History
The formation of an inverted image by a pinhole was first observed by the philosopher Mo Ti in 5th century BC. Sir David Brewster (Scottish scientist) is credited for the discovery of pinhole photography. Pinhole photography became popular in the 1890s. It was used as a scientific instrument of observing solar eclipses.
What Is A Pinhole Camera?
A pinhole camera, also known as a camera obscura, is made out of cans or boxes. Pinhole cameras are used for science experiments, for art and for fun. It is a camera without a lens and with a single small hole which focuses the image on to a screen. As soon as the light enters the pinhole, an inverted image is formed. Pinhole cameras are generally used for capturing and observing motion (like movements of sun during solar eclipse).
Pinhole Photography Characteristics
A pinhole camera produces more blurred and softer images then by a camera with lenses. Field depth (focal point) is infinite. Pinhole images relatively more enlarged than the images by a lens camera. The pinhole is a primitive technology and its images suffer color aberration. Light sensitive screens are exposed to light for longer period due to very small aperture of pinhole camera.
Making a Pinhole Camera
Designing pinhole cameras is great fun. What is needed is a box – square or round (oatmeal container), black electric tape, aluminum foil, small nail to make a hole, pair of scissors, wax paper and bright source of light (sun). First, the box is cut from the bottom (say about 2 inches). The open part of the box is covered with the wax paper with the help of tape. The large part of the box are taped back together and also the two parts of the box put back together and taped. The whole thing is covered with the aluminum foils to ensure that light does not pass through it. A hole is pierced in the middle of the box with the help of the nail. The box is moved upwards, and moving shadows can be observed on the screen. When the box is put in the sun light and upside down images are formed.
Pinhole Camera Formula
Pinhole camera works n the basic laws of optics. The characteristics of the image produced by pinhole camera depend on the curvature of the hole, the distance of the image (screen) from the hole and distance of the object from the hole. The focal point of the pinhole camera can be calculated by dividing the product of distances of image and object from the hole with summation of distances of image and object from the hole.
Money can buy the latest technology camera. But making a pinhole camera from scratch has experience worth a lot more. Making students make a tool like pinhole camera imparts practical knowledge of the subject into the children. But more than that, it makes learning fun and enjoyable.