The Photo Triangle

photo triangle

In photography three items to think about while shooting makes up the photo triangle. You have to think about these three items to create an amazing photo. Part of thinking about it requires also knowing how you want your photo to turn out. The three items are ISO, Aperture, and Shutter Speed. In the book, I am using The Visual Toolbox by David Duchemin gave the challenge to go through each side of the triangle and take a picture using each number to see and understand how each side works.

Photo Triangle – ISO

ISO tells the amount of light being let in. The smaller the number means less light. A higher number lets in more light. The numbers go 100, 200, 400, 800, 1600, 3200 and so on. After about 1600 on ISO, the picture can become a little grainy. Notice in the example below how the more light let in, the picture fades to white.

Photo Triangle – Shutter Speed

Another side of the triangle is called shutter speed. We can think of the shutter as a closed eyelid. Each time we take a picture we open that eyelid or shutter to capture the picture. The speed of the shutter tells how long it stays open. The shutter speed is measured in seconds or a fraction of a second. Below see an example of what happens to a photo from 1/60 shutter speed to 1/4000 speed.

Photo Triangle – Aperture

The Aperture, also called the f-stop, is the size of the hole the light goes through. The larger the hole the more light that enters. In this case, the smaller number indicates a larger aperture and a larger number indicates a smaller aperture. Below shows what happens when the aperture or f-stop goes from a large hole f5.6 to a small hole f32.

The correct combination of using these three items helps to create amazing photos. The ISO tells the sensitivity to the light. The shutter speed is the speed of the shutter staying open. Finally, the size of the aperture tells how much light to let in. Combine the three, create the photo triangle, and once understood you can take pretty awesome photos before photoshop.


  1. TY for blogging this, it had been quite handy and helped a ton Great theme, did you make it on your own? Looks superb! Facinating post to check on this awesome blog. Never write any replies but now i just did not resist ..

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