1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32

-a whole within the lens through which light travels. the larger the whole the more light passes through.

-the SMALLER the number the HIGHER amount of light

-multiply or divide by 1.4 to get to the next number

-an example of a small aperture is 32, an example of a large aperture is 1

written as f/1, f/1.4, f/2 and so on B,T,1,2,4,8,15,30,60,125,250,500,1000,2000

-all shutter speeds are fractions fractions of a second (1/15, 1/30, 1/60, and so on)

-1/30 lets in TWICE as much light as 1/60 and so on

-shutter speed is the length of time a camera shutter is open