The pinhole camera is  a type of camera obscura. The concept of a pinhole camera was first known by the philosopher named Aristotle (B.C). He discovered that by passing sunlight through a pinhole could create a reversed image of the sun on the ground. He used this idea to observe the eclipse without staring directly at the sun and for the artists to make sketches. But the only problem was, he cannot explain this phenomenon. He had no idea why the image created was reversed. 

During the 13th to 14th century, the idea of Aristotle which pertains to the pinhole camera was used by the scientist for their experiments. But only one person can explain why the images were upside down or reversed when the light passes through the pinhole. This scientist is an Arab physicist (someone who studies physics) named Ibn Al-Haytham or Alhazen. 

This is also known as a “darkroom” or "dark chamber" having an aperture usually provided with a lens through which light from external objects enters to form an image of the objects on the opposite surface. (Merriam Webster) During ancient times, camera obscura was only used by the people for viewing or drawing purposes like what Aristotle did. 

In the 16th century, Italian artists shrunk the large chamber to a portable box, replaced the pinhole opening with the lens, added a mirror to invert the image and a translucent ground glass screen to display it. They traced teh projected image by hand.

The first-ever photograph was developed by Joseph Nicephore Niepce in the year 1827. He called his work as heliographs or sun prints, and it is considered as the prototype for modern photography. Niepce placed an engraving onto a metal plate coated in bitumen, and then exposed it to light. The shadowy areas of the engraving blocked light, but the whiter areas permitted light to react with the chemicals on the plate. When Niepce placed the metal plate in a solvent, gradually an image, until then invisible, appeared. However, Niepce's photograph required eight hours of light exposure to make the image visible and would immediately fade away. 

Louis Jacques Daguerre is a scientist who is also interested in photography. In 1829, together with his partner (Niepce), they tried to improve the process Niepce had developed and conducted several experiments but failed. Niepce’s death did not stop Daguerre to continue what they had started and used his partner’s idea to make the image permanent when exposed to the chemicals. 

Finally, in 1839, after several attempts, he developed a more convenient and effective method of photography, called daguerreotype. Also, Daguerre was able to reduce exposure time to less than 30 minutes and his process created a lasting image, one that would not change if exposed to light. He was considered as the inventor of the first practical process of photography. 

With the previous experiments made by the other scientists, it was already known that when silver and salt are combined it will be sensitive to light. An English Botanist and mathematician named William Henry Fox Talbot wanted to draw everything he sees but could not master drawing. Therefore, he decided to experiment to make a fixed image using light and silver-salt solution. This is also called as Talbotype. 

STEPS USED BY WILLIAM HENRY FOX TALBOT 

1. Make a “silver-salt solution”, a mixture of silver and salt and soaked the paper. 

2. Place something (Leaves for example) in the paper soaked with the solution or known as sensitized material. 

3. Put it under the sun. 

Part of the paper (sensitized material) which is not covered by the leaves are darkened when exposed to sunlight. This was known as a photogenic drawing and the first negative image produced. Talbot also made contact prints, reversing the light and shadows to create a detailed picture. 

In 1841, he perfected this paper-negative process and called it a calotype, Greek word for a beautiful picture. Many scientists and inventors had greatly contributed to the field of photography. And with the advancement of technology, digital cameras, and mobile phones are now the most popular and convenient types of a camera which captures photographic images to its digital memory known as a memory card.