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9 - Exposure Introduction


Exposure is the amount of light striking the sensor.

Three Controls

The amount of light is controlled by using three controls.


ISO is a measure of how sensitive the sensor is to light.

Lens Opening

The lens opening is an iris-like device in the lens.

By changing the size of the lens opening, the intensity of the light reaching the sensor is varied.

Lens opening is also known as aperture, f/stop, and rarely, diaphragm.

Shutter Speed

When the shutter opens, the duration of the light reaching the sensor is controlled.

Let's look at ISO, lens opening, and shutter speed.