# What is camera obscura?

## What is camera obscura?

As the name suggests, many historical camera obscura experiments were performed in dark rooms. The surroundings of the projected image have to be relatively dark for the image to be clear.

### How do you make a camera obscura from a box?

1. Fold down the flaps of one side of the box and tape them. down using black duct tape. This taped side will be the bottom of your camera obscura. 2. Place template A on top of one side of the box and center it. Trace around the inside of the window of the template to create a 1 ½” square.

#### How is the sharpness of a camera obscura achieved?

Optimum sharpness is attained with an aperture diameter approximately equal to the geometric mean of the wavelength of light and the distance to the screen. In practice, camera obscuras use a lens rather than a pinhole because it allows a larger aperture, giving a usable brightness while maintaining focus.

How many holes does a camera obscura have?

Italian Jesuit philosopher, mathematician, and astronomer Mario Bettini wrote about making a camera obscura with twelve holes in his Apiaria universae philosophiae mathematicae (1642). When a foot soldier would stand in front of the camera, a twelve-person army of soldiers making the same movements would be projected.

Camera obscura is a very old device. Oldest mention of its effect is by Mozi, Chinese philosopher and the founder of Mohism, during the 5th century BC. He noticed that an image from camera obscura is flipped upside down and from left to right as a result of light’s moving in straight line.

Did Euclid mention the camera obscura phenomenon?

Euclid is sometimes reported to have mentioned the camera obscura phenomenon as a demonstration that light travels in straight lines in his very influential Optics (circa 300 BC). However, in common translations no remarks of anything that resembles a camera obscura can be found.

## What did Aristotle say about the camera obscura?

The Greek philosopher Aristotle (384 to 322 BC) was familiar with the principle of the camera obscura. He viewed the crescent shape of a partially eclipsed sun projected on the ground through the holes in a sieve and through the gaps between the leaves of a plane tree.

### What do you need to make a camera obscura?

The modern use of the camera obscura as an epistemic machine had important side effects for science. While the use of the camera obscura has dwindled, for those who are interested in making one it only requires a few items including: a box, tracing paper, tape, foil, a box cutter, a pencil and a blanket to keep out the light.