Is a good prime lens the best way to learn composition? There are many blog posts singing the praises of a prime lens and about how the best way to learn composition is to use a prime lens. Using a prime lens is certainly one way to learn composition, but it is not the best or only way. Without the guidance or input of others, no form of artwork can truly grow. Growth in any part of life requires interactions and input from a community. Perhaps the best way to learn photography is from a good teacher.
One of the reasons many believe that the best way to learn composition is with a prime lens is because it severely limits the composition choices a photographer can make. By limiting our choices, we are pushed to think harder and differently to get to our composition. In other words by creating a smaller box, we're pushed to think outside the box. But you do not need to use a prime lens to create such constraints. For instance, what about shooting in just a square format, like what one does on instagram? You can also shoot only in black and white or in any other monochrome setting. What about shooting with a fisheye? What about limiting yourself to just a horizontal or just a vertical frame?
There are many ways in which to learn composition. But to say that there is only one best way is very misleading. It is as if to say that the best way to learn how to paint is to use particular brush with a particular color of paint. By creating constraints, we are certainly pressed to look at the world differently and there is certainly merit in this. However, it is not the singular answer or the best way.