Samsung BN59-01012A 数据表

Concepts in Photography

Aperture

The aperture is one of the three factors that determine the exposure. The 
aperture housing contains thin, metal plates that open and close to let 
light through the aperture and into the camera. The size of the aperture 
is related to the amount of light: a larger aperture allows more light and a 
smaller aperture allows less light.

Minimum aperture

Medium aperture 

Maximum aperture

Aperture opened slightly

Aperture opened wide

The size of the aperture is represented by a value known as an "F-number." 
The f-number represents the focal length divided by the diameter of the 
lens. For example, if a lens with a 50 mm focal length has an f-number of 
F2, the diameter of the aperture is 25 mm. (50 mm/25 mm = F2)  
The smaller the f-number, the greater the size of the aperture.

The opening in the aperture is described as the Exposure Value (EV). 
Increasing the Exposure Value (+1 EV) means the amount of light doubles. 
Decreasing the Exposure Value (-1 EV) means the amount of light halves. 
You can also use the exposure compensation feature to fine-tune the 
amount of light by subdividing exposure values into 1/2, 1/3 EV, and so on.

+1 EV

F1.4

F2

F2.8

F4

F5.6

F8

-1 EV