It is often said that triangles and diagonals add ‘dynamic tension’ to a photo. 

What do we mean by ‘dynamic tension’ though? This can be a tricky one to explain and can seem a bit pretentious. Look at it this way, horizontal lines and vertical lines suggest stability. If you see a person standing on a level horizontal surface, he will appear to be pretty stable unless he’s stumbling out of a pub at 2am. Put this man on a sloping surface and he’ll seem less stable. This creates a certain level of tension visually. We are not so used to diagonals in our every day life. They subconsciously suggest instability. Incorporating triangles and diagonals into our photos can help create this sense of ‘dynamic tension’.

Incorporating triangles into a scene is a particularly good effective way of introducing dynamic tension. Triangles can be actual triangle-shaped objects or implied triangles. I’ll explain this in more detail in a moment.

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Photo from PetaPixel.com