Defining the Decisive Moment

Henri Cartier-Bresson called his 1952 book Images a la Sauvette, translated as The Decisive Moment, yet according to Wiktionary, a la sauvette means hastily, hurriedly; or on the sly.  Other translations exist.  His Behind the Gare St Lazare 1932:
http://iconicphotos.wordpress.com/2009/04/23/behind-the-gare-st-lazare/
shows the moment before the leaper lands, and hastily describes the photographer's action in capturing the image and I suppose this was the photographer's decisive moment.  The leaper's decisive moment has passed; it was when he leapt; his trousers' moment will arrive when he lands, which would also make an interesting photograph.  The image is cinematic: it depicts a fairly quiet scene, the only action is that of the leaper, about to leave the frame.  The next frame will be full of action. For me, what makes the photograph great is that it involves the viewer, who's allowed to speculate what happens next.

Timing jumps is difficult.  I took a dozen shots of sheep landing before I caught one taking off.  The landing shots were nothing special.  I wonder how many shots Cartier-Bresson took before he was satisfied he'd got the one he wanted; how many pairs of wet trousers were involved.

Robert Capa's famous Death of a Loyalist Soldier 1936 is not about what happens next:
http://upload.wikimedia.org/wikipedia/en/7/7b/Capa,_Death_of_a_Loyalist_Soldier.jpg
It shows the moment the catastrophe occurs.  The viewer wonders how the photographer caught this moment at all; then how he did it without getting shot himself.  Capa was killed years later in Vietnam, so maybe he didn't fake it.  The composition works; the open space in front of the victim is revealed as deadly; his rifle, leaving his grasp and the frame, is cast aside.

E O Hoppe is a photographer I'm fond of.  One of several photographs titled At the counter in a snack bar, London 1935 shows a uniformed young man holding a spoon to his lips, but looking away to his left, thinking of something else, perhaps remembering.  A moment of contemplation.
http://farm7.static.flickr.com/6214/6311141557_93fc1afb3d.jpg

My spoon-wielder below has his whole body and attention focussed very much on the last mouthful.

And here's a tea-drinker, so engrossed in his book he doesn't even look at the mug.

Resting the camera on the table, I took several on the sly shots of this man drinking tea while reading his Kindle, but here he's just got the mug to his lips.  He'll have to break away from his book to start to drink.  Wonder if he's reading one of mine?

 I like the fact that this biker is holding his spectacles in his teeth while he removes his helmet.  The background branch parallels the handlebars and adds interest to an otherwise plain sky.  The moment of transition between the armoured, helmeted biker and the ordinary man who wants a cup of tea.

 

These girls in Trafalgar Square are very self-aware.  The three Burberry bags help bring them together in a moment of still self-contemplation.
My son had to explain to me that the I-pad can be used as a mirror.

Here's my favourite.  They're having fun, but the body language is interesting.  The posh lady with the cat bag has distanced herself from the others, but compensates by laughing loudest.

And a moment of quiet; these smokers aren't even looking at each other.

Maybe the man on the left is about to say something to break into the other's thought; maybe not.
I like the band of light illuminating the important centre section of the seated man's face.  The diagonal bar of light cuts off the lines of their gaze.  The dark corner of the door delimits it and prevents the viewer's gaze slipping away in that direction.