Focal Length & The F-Number Mystery — Why Do We Call Them F-stops?

Focal length, f-number, f-stops - are you set for a little physics on the part of the art called photography? As much as photography is about capturing the shots with an artist's eye, it is equally about understanding the science applied in the creation of a photograph. At a preliminary stage, we hold the camera in the hand and learn to see through the camera's eye. As we spend more and more time with this awesome machinery (the shot-gun), we tend to learn more about photography like how does the camera work, the essence of drawing with light and the physics of photography. In the later realm, i.e., the physics of photography, we discover some of the very powerful basics of photography - the focal length, f-numbers and f-stops. This is what I will demystify in today's post - the meaning of these mysterious numerals that are almost always found...