Traditional Culture Encyclopedia - Photography and portraiture - I don't understand a theoretical problem of the New York Institute of Photography. I don't know why, so I want an expert explanation.

I don't understand a theoretical problem of the New York Institute of Photography. I don't know why, so I want an expert explanation.

Every time the lens aperture is different, the amount of light entering is halved at the same time.

The integer multiples of the aperture value are: f 1, f 1.4, f2, f2.8, f4, f5.6, f8, f1,f 16, f22, etc. These gears are all integer gears, and the numbers from small to large represent the aperture from large to small. The difference between f2.8 and f 1 1 is four steps, so their light input is 16 times.