Stops of Light.
Stops of light are the way we measure and describe the amount of light in we need to correctly expose an image.
It helps us better understand how much brighter or darker an image will be when we make adjustments to the camera settings.
Think of stops of light as steps on a staircase. Each step represents a doubling or halving of the amount of light. When we move up one step (increase by one stop), we double the amount of light, making the image brighter. When we move down one step (decrease by one stop), we halve the amount of light, making the image darker.
Assuming you're taking a photo and the exposure settings are set to 1/100th of a second shutter speed, f/8 aperture, and ISO 200. If you wanted to increase the exposure by one stop, you can either double the amount of light by either:
Decreasing the shutter speed to 1/50th of a second (letting the shutter stay open for twice as long), or
Opening up the aperture to f/5.6 (allowing twice as much light to reach the sensor), or
Increasing the ISO to 400 (making the sensor twice as sensitive to light).
Similarly, if you wanted to decrease the exposure by one stop, you can either:
Increase the shutter speed to 1/200th of a second (letting in half as much light),
Close down the aperture to f/11 (allowing half as much light to reach the sensor), or
Decrease the ISO to 100 (making the sensor half as sensitive to light).
Each stop represents a significant change in the amount of light, and photographers use this concept to control the exposure and achieve the desired brightness or darkness in their images.
| Aperture (f-number) | Stops of Light |
|---|---|
| f/1.4 | +3 |
| f/2.0 | +2 |
| f/2.8 | +1 |
| f/4.0 | 0 |
| f/5.6 | -1 |
| f/8.0 | -2 |
| f/11 | -3 |
| f/16 | -4 |
| f/22 | -5 |
Each column in the above table represents a stop of light. The f/4.0 aperture in this instance is considered the "base" or reference point, representing 0 stops of light. When you move one step to the left on the scale (decrease the f-number), you increase the exposure by one stop (double the amount of light). Conversely, when you move one step to the right (increase the f-number), you decrease the exposure by one stop (halve the amount of light).
For example, if you change the aperture from f/4.0 to f/5.6, you are moving one stop to the right, which reduces the exposure by one stop (halving the amount of light). Similarly, if you change the aperture from f/4.0 to f/2.8, you are moving one stop to the left, increasing the exposure by one stop (doubling the amount of light).
This scale provides a reference for understanding the stops of light associated with different aperture settings. It helps photographers make precise adjustments to control the exposure and achieve their desired lighting effects.
