WHAT IS FOCAL LENGTH?
Focal length is a term used to describe the angle of view offered by a lens. A ‘long’ telephoto focal length such as 300mm lets us fill the frame with distant objects, while a ‘short’ wide focal length like 20mm gives a broader field of view and lets us fit more of the scene into the frame. These measurements are based on the distance between the sensor and the optical centre of the lens (the point where light rays passing through the lens converge to form a sharp image).