Understanding the Exposure Triangle

Understanding the Fundamentals Can Take You a Long Way

The most important part of photography is the exposure of every shot. Exposure is simply the amount of light hitting an electronic image sensor. Controlling exposure is about controlling and manipulating the light around you and this control is what makes photography a unique form of art.

Exposure is controlled by 3 things: shutter speed, aperture, and ISO. These are the three elements to what is known by most photographers as the “exposure triangle”. Understanding each element will allow you to get the perfect exposure for your perfect shot!

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Shutter Speed

The shutter of a camera opens and closes to take light in and record it. Shutter speed determines how long the shutter stays open to take in light. Shutter speed can be as slow as several hours to as fast as 1/8000th of a second. Slower shutter speed causes your image to become brighter and creates a blur for any movement. The blur from a slow shutter speed can be used to your advantage.

For example, a slow shutter speed like 5 seconds can show the circular light trail of a ferris wheel at night. It’s important to remember that when using a slow shutter speed, camera motion can cause the whole image to become blurred so it’s best to use a tripod or any other camera stabilizers. Faster shutter speeds, however, are meant to freeze motion and can leave no blur at all.

A shutter speed of 1/250 of a second is usually enough to freeze most moving objects and a speed of 1/1250 a second can freeze the wings of a flying bird. These fast shutter speeds make your images darker, the opposite of slow shutter speeds because the shutter closes much faster and less light gets in.

Fast shutter speeds work best with plenty of light and are generally used for action shots like wildlife or sports. The movement of the subjects and the effects you want to create is what determines the ideal shutter speed you want to use. Slower speeds give more light and more motion blur, faster speeds give less light and less motion blur.


The aperture determines how big a lens’s diaphragm opens. The diaphragm is an opening that light has to go through. A wider opening means more light comes through and a smaller opening means less light comes through. The “wideness” of an aperture’s opening is written with numbers like f/1.4 as a low aperture, f/3.5, f/5.6, and f/8 as a high aperture.

These numbers can be seen as fractions, so f/1.4 means the lens is 1/4 open and f/5.6 means the lens is 1/5.6 open. Using a lower aperture like f/1.4 not only brings in more light but also creates a shallower depth of field. A shallow depth of field is best used for portraits because it keeps the subject clear and blurs the background, an effect known as “bokeh” that everyone loves!

A higher aperture allows for a bigger depth of field which is ideal for landscape photography. Low aperture for more light and shallow depth of field and high aperture for less light and bigger depth of field.


ISO should be the very last thing you adjust when trying to get the ideal exposure. ISO simply brightens the picture that the camera takes. Brightening the photo through ISO does have drawbacks however because, unlike shutter speed and aperture, ISO doesn’t capture more physical light but instead just brightens whatever light is in the photo.

This brightening can cause grain, little dots all over the picture that creates a lower quality final image. ISO typically has a range going from 100 to 6400 with 100 being the least bright and 6400 being the brightest. You should try to keep the ISO as low as possible and only raise it when adjusting the shutter speed and aperture doesn’t give you the brightness you need. High ISO means more light but more grain, while low ISO means more light but a higher quality image.

The exposure triangle is a basic but essential part of photography. Now that you know what the three elements of the triangle are, you can confidently adjust these settings to get the perfect shot at the right exposure!

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