Aperture

Chapter Nine

An aperture is a hole or an opening through which light travels. It is also called as adjustment of the lens opening measured as f-number,  which controls the amount of the light passing through the lens. The aperture f-numbers are obtained by the manufacturer at the time of manufacturing the lens as per following Formula :

Focus

Chapter Eight

Adjustment of the distance between subject to film (Camera) is called focus. There are Two types of  focusing, manual focus and auto focus

Manual focus

In the field of photography , a manual focus camera is one in which the operator has to adjust the focus of the lens by hand. Before the advent of auto focus , all cameras had manually adjusted focusing thus, the term is a retronym.

Description of Photography Basic Techniques and Terminologies

Chapter Seven 

 Focus

The adjustment to place the sharpest focus where it is desired on the subject .

Aperture

Adjustment of the lens opening, measured as f-number, which controls the amount of light passing through the lens. Aperture also has an effect on depth of field and diffraction  the higher the f-number, the smaller the opening, the less light, the greater the depth of field, and the more the diffraction blur. The focal length divided by the f-number gives the effective aperture diameter.

Camera Design

Chapter Six

Pinhole camera

A pinhole camera is a very simple camera with no lens and a single very small aperture. Simply explained, it is a light-proof box with a small hole in one side .  Light from a scene passes  through this single point and project  an inverter image on  the opposite side of the box. Cameras using small aperture and the human eye in the bright light both  act like a pinhole camera.

Timeline of Photography Technology

Chapter five

1822 Nicephore Niepce takes the first permanent photograph, (of an engraving) of *Pope Pius VII*, using a non-lens contact-printing “heliographic process”, but it was destroyed later; the earliest surviving example is from *1825*

In *1826* Nicephore Niepce takes the first permanent photograph from nature, a landscape that required an eight hour exposure