Here is a copy of a post I did on photo.net forum. I think it summarizes a bit what I think about this famous idea.
First I think there is global misunderstanding in the idea of “Decisive Moment”, how it applies to HCB (who was not the one who brought the idea upfront since it was merely the English translation for ‘images à la sauvette”) and how it can apply in photography more generally.
It is very important to recall that HCB was primary a painter, and more specifically an artist inspired and nourished by surrealism. There is confusion on the fact that he long time claimed to be a photojournalist, but that was mainly because of Capa persuading him that nobody would be interested in him if he would present himself as a surrealist artist. Indeed HCB did not really care about the facts and he said he found them ‘boring’. But he was obsessed by what he would often call “geometry” and the decisive moment for HCB would occur at the exact moment when “geometry” is here, according to his own architect-like vision, which could only last a fraction of second (and the fraction of second is what would make a difference between an average picture to a good one).
So to me the whole idea of decisive moment refers more to “style”, or better said the vision rather than as an intrinsic quality of the facts captured. In other words every photographer has her/his own “decisive moments” and I believe it has more to do with the vision than the facts.
So… are “decisive moments” rare ? yes and no… A moment/space of reality can offer (or not) decisive moment for a specific vision. When Helen Levitt did the image of 4 girls with bubbles it is of course a decisive moment, consistent with her vision. But when Lee Friedlander did the portrait of his wife with the car it is also a decisive moment (I mention Friedlander because he is often presented as a non-decisive moment photographer)
Furthermore I believe that the decisive moment is what makes an image tell of its author or at least her/his vision. For that reason I am not very sure to be able to pinpoint decisive moment in my photographs. Maybe (?) I should better trust the feeling that I recall from the shoot, so that this one:
or this one:
… can be good examples of moments that worked for me.