Introduction to Photography 05 Relationship among Aperture, Shutter and ISO

Aperture, shutter and ISO determine whether the amount of light entering is reasonable (whether the exposure is normal).

In the case of sufficient light, in order to ensure the image quality, low ISO between 100 ~ 200 is usually selected.

If ISO is not considered for the time being, let's consider the relationship between aperture and shutter first. Take the faucet as an example, compare the opening of the valve to the aperture, the time for water to reach the shutter, and compare the total outflow and light intake.

So if you want to get enough light (that is, normal exposure), it's like pouring a glass of water under the tap. When the aperture (valve) is small, the shutter time (time) needs to be long.

The amount of light entering a normally exposed photo is fixed, so the aperture is larger and the shutter time can be shorter. Very easy to understand.

If you want to take a blurred effect, you should give priority to the combination of large aperture and short shutter.

If you want to shoot the track or slow door effect, you need to use a combination of long shutter and small aperture.