Yousuf Karsh had two minutes...maybe three.
Standing in antechamber of the Canadian Parliament, Karsh set up his view camera and waited for his subject, British Prime Minister Winston Churchill.
This was during World War II, of course - the Blitz. The German Luftwaffe was bombing London nightly, battering the people and buildings in an attempt to soften them, either so they would not fight so hard against the Nazi plan to rule all of Europe, or possibly in advance of a future invasion.
One of the reasons, some even say a defining one, that the invasion of England never happened, was the portrait of Winston Churchill, as recorded by Yousuf Karsh and published worldwide, including the cover of Life magazine. In it, Churchill is depicted as a stern and formidable man. Karsh, himself, entitled the shot "The Roaring Lion".
Portraiture is the Art of photographing the human heart for those who cannot stand the sight of blood. Karsh was one of the best practitioners to ever expose film. Despite an established reputation and several great shots to his credit, however, Churchill was not very cooperative. When he finished his speech to the Canadians, he walked out of the chamber and into the room, no doubt wondering which member of his staff he was going to give hell to for setting up this photo opportunity in the middle of his very important journey.
At that moment, Karsh had a shot of a stern looking man - a man who was clearly not very happy. It was almost perfect, except that Karsh could see the subtle difference between taking a shot that defined the man and a shot of a man who didn't really care to have his picture taken.
When you look at the shot, notice that there is no cigar in Churchill's mouth. A well-known aficionado, there are more shots of Churchill with a cigar than there are without. What Karsh did in the two minutes (maybe three) that he had, was to take the shot he had been given and, with a simple act, create the shot he wanted.
Without warning or permission, Karsh walked up to Churchill, reached up, and took his cigar out of his mouth. Or so the story goes - he might have just asked Churchill to lose the cigar, but I doubt it, since that might have caused him to lose Churchill. Churchill put his hand on his hip, deepend his furrowed scowl and leaned forward toward the upstart photographer. Clearly, this was something you did not do to Winston Churchill.
There are less savory examples of photographers changing things around in their photos to get the shot they wanted. Henri Cartier-Bresson, the master of capturing "the decisive moment" is rumored to have set up and rehearsed a shot or two. And no self-respecting mother is ever going to admit that their toddler's laughter was more the result of the squeaky toys in the studio then their own presence.
The point is that Londoners, huddled in basements and subway stations, saw that photo and saw themselves - a part of their very character that the bombings had all but wiped out of them, and they found a new resolve. Despite Hitler's considerable propaganda machine, there never was such a shot of him for the German people. Let's face it, in a dog fight, are you going to bet on the bulldog or the dachsund?
If you know what you want to express, and you have the power to change something - anything - to make that expression more effective while remaining true to the subject matter, I'm not going to call the creativity cops on you for doing so.