It works by separating the mirror flip and apertureopening into two steps.
它将镜面翻转和光圈打开分为两个步骤。
2
Each number does not necessarily correspond to a specific size of the apertureopening, but is a relative number.
每组数字并非是光圈打开大小的特定值，只是一个程度的相关体现。
3
This is because you halved the amount of light being let through the apertureopening, but let in twice as much light by keeping the shutter open longer.