Pinhole Camera

A camera is a device that captures an image. These optical devices are of types - digital and Reel camera (which Light Sensitive Material). The reel cameras allow the light to discharge the light-sensitive material. This forms the negatives that a technician can develop later into photographic prints. The digital cameras capture the virtual image and store it in digital form. Anyone can print these images just like any other digital data.

Pinhole Camera

A pinhole camera is the simplest form of camera. The device doesn't have a lens. Instead, it is a light-proof box that has a small hole with a small aperture. This helps the camera to focus light on the light-sensitive material. The image formed is inverted, and the phenomenon is known as the camera obscura effect.

Important Terms Related to Pinhole Camera

The important terms to understand the Pinhole Camera are as follows:

Aperture: An aperture is the variable opening that allows the light to enter a camera.
Camera Obscura Effect: This is a phenomenon noticed in camera obscura, which is the basis of modern cameras. The setup includes a camera with a small hole that forms an inverted image of any object in front of it on the opposite wall.
Light Sensitive Material: This is usually a film with a silver halide coating. The coating is sensitive to light and discharges, giving a negative of the image.

How is an Image Formed in a Pinhole Camera?

Just like in the camera obscura, you can see the image of the object, person or landscape forming on the opposite side of the hole. However, the image is inverted and slightly dim due to a very small amount of light entering the room. Now imagine a box (in a similar fashion) with just a small hole to take in light and a light-sensitive film on the opposite end of the hole.

The light entering this box will form an inverted image on the light-sensitive film. The time required to form an image will be more since the light entering the pinhole camera is minimal. The convex lens improves this time in a normal camera when it converges the light on the point of image formation.

Image Characteristics

The image formed by the Pinhole camera has the following characteristics:

The image undergoes inversion on both the x and y axes.
The image formed on the screen is smaller in size when compared to the image size. The intensity of the image is low.
The image formed is real and thus can only be obtained on a screen.
The process of image formation in the pinhole camera can help study the rectilinear propagation of light.

Construction of a Pinhole camera

Materials Required

Cardboard Box
Aluminium Foil
Tape
Cardboard
Pin
Light Sensitive Material

Procedure

Cut the cardboard to make a hole. Cover the hole with aluminium foil.
Tape the Aluminium foil to the cardboard and make a small hole in the foil using the pin.
Remove the rear end of the box and use the loose cardboard as a screen to obtain the image. Once you obtain the image on the screen, replace it with the light-sensitive film.
Tape the camera to make it light-proof. Your pinhole camera is ready.

Applications of the Pinhole Camera

The camera is ideal for studying or capturing extremely bright sources or objects since it lowers the source's intensity and makes it easy to study. For example, it is ideal for studying the movement patterns of the sun over a period of time. ]
It is a very safe method to see and study the solar eclipse in real-time without damaging your eyes.
Since these cameras lack any digital or metallic signature, they are extremely difficult to detect. Consequently, they find their uses in spying purposes.
The images rendered by the pinhole camera are raw, and thus they hold a unique artistic value.

Frequently Asked Questions About Pinhole Camera

Ques: What is the prominent advantage of a pinhole camera?
The major advantage of a pinhole camera is that they are very simple in their construction and operation and do not require any special expertise to operate.

Ques: What is the major disadvantage of a pinhole camera?
The biggest disadvantage of the pinhole camera is that forming an image takes a long time due to the small amount of exposure of the light-sensitive film.

Ques: What are the prime objectives of the use of a pinhole camera?
Apart from the artistic purposes, the camera is ideal for solargraphy. Solargraphy is the study of the movement of the sun across the sky over a period of time. The prime objective is to decrease the source's intensity to make it possible for the human eye to effectively study the source.