What is the Exposure Triangle

The exposure triangle is an analogy or standard way to explain the result that aperture, shutter speed, and ISO have on exposure. Each setting represents a side of the triangle with the overall size of the triangle representing the exposure (brightness) of the image.

You can think of the triangle as a piece of pie or a slice of pizza, the bigger the slice the brighter the photo. Make the photo brighter or darker by adjusting one or more of the three settings. The setting(s) you choose to change is based on the creative control that we have learned in our past lessons; Creative control with aperture, and “Motion” the creative control behind shutter speed.

©Trevor Awalt_Exposure Triangle

If you slow down the shutter speed, toward 1/4, there is a longer duration for the light to be available to the sensor resulting in a brighter exposure and as a result a larger triangle. Conversely, if you speed up the shutter speed, toward 1/1000, there is a shorter duration resulting in a darker exposure.

By increasing the size of the aperture, toward f/2.8, which allows more light into the camera resulting in a brighter exposure. Conversely, decreasing the size, toward f/16, of the aperture reduces the light into the camera resulting in a darker exposure.

Also, increasing, toward 1600 (more noise), the ISO amplifies the image from the sensor resulting in a brighter exposure. Conversely, if we decrease, toward 100 (less noise), the ISO it decreases the amplification resulting in a darker exposure.

Adjusting any of the three settings; aperture, shutter speed, and/or ISO, requires consideration of the creative control that aperture and shutter speed provide as well as considering the quality of our image with ISO at the same time achieving a proper exposure.

In our next lesson we are going to discuss how the camera measures exposure and how you can help the camera control the exposure in auto and semi-automatic modes.

 

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