THE EXPOSURE TRIANGLE

In photography, exposure refers to how much light are are allowing to reach the sensor of your digital camera. This will determine how light or dark your image will appear. This is all determined by three camera settings: Aperture, Shutter Speed, and ISO. Together, these three variable are known as the exposure triangle.

Using the expose triangle will result in a photo that is either underexposed, properly exposed, or overexposed. Have a look at the photos below for an example. These photos are from the ETDphotography website. Be sure to visit their website for some great resources as well as a fantastic analogy about the exposure triangle.

Overexposed

The Variables Explained

As mentioned above, there are three variables that control how your image will appear.

Aperture

Aperture is what controls the area over which light can enter your camera. As shown in the image above, it will either increase or decrease the diameter of the opening that allows light through. The bigger the aperture, the more light that is allowed in and vice versa. Learn more about aperture in the aperture section.

Shutter Speed

Shutter speed controls the duration of the exposure. The faster the picture is taken, the more frozen in time it appears. The slower the picture is taken, the more blur that can appear. This is usually measure in fractions of a second but there are times that you might need to take a slower picture. Learn more about shutter speed in the shutter speed section.

ISO

ISO stands for International Standards Organization, and it is a standardized industry scale for measuring sensitivity to light. You can adjust your digital camera’s settings and have the sensor become more sensitive to the available light. This can be quite helpful in low light situations. Although this is a great feature, there can be some drawbacks. Learn more about ISO in the ISO section.

Interactive Tool

You can learn how one variable of the exposure triangle affects the others by using the interactive tool located at www.exposuretool.com. When you go to the website, leave the option of ‘manual’ selected and try using each of the sliders. See how they affect one another.

Although these factors may not mean that much to you now, they will over the course of the lessons listed above.