Nothing is more important in photography than catching a Decisive Moment. Such moments makes or breaks an image. Here is one that is pretty decisive. I young lady hanging in the air at the landing place of the Copenhagen Marathon, May 20, 2012.
That said, what is a decisive moment? Sometimes it is easier done than said, because all do not agree on what a decisive moment is.
In a way all photographs are decisive moments. They can never be repeated and for whatever reason the release button is pressed, it renders a photographs of a decisive moment. Many people stick to such a definition and you will see lots and lots of photographs described as decisive moments.
However, such a wide definitions renders only small letter decisive moments. Let’s call them that.
Decisive Moments with capital letters are very different. More like the definition given by Cartier – Bresson: To me, photography is the simultaneous recognition, in a faction of a second, of the significance of an event as well as of a precise organization of forms which give that event its proper expression. (The Minds Eye, Aperture 1999, page 42). These moments place a demand on both the content of an image as well as of its form. Compositions play a larger part.
How do I know the difference, you may ask? The best way to know the difference between small and capital letter decisive moment is to take a good look at the image. With the same eyes and mind that you look at the world around you. If the image hits you as being striking it probably is. If it hits you as being Decisive it probably is. Look for the content and look for the form. The overall composition.
Can you learn how to take pictures of capital letters Decisive Moments? Good question. Some of it yes, but not all. It is like in the real world: Luck is important, and if you prepare for luck you will probably get it. You certainly can prepare.
And the other way around.
Good luck with it.