In reply to andrewmcleod:
A good climbing example might be the photo of the FA of Woubits, taken of Whillans by Brown (or vice versa) in 'The Black Cliff'. The rain's pelting down so much, it's almost like lines on the photo. It's black and white. The climber is blurry, dark, indistinct (well, as I remember, not seen it for yonks!)
But the remarkable thing is that all these deficiences 'make' the photo. They become its strengths. It's not a professionally posed shot (though nothing wrong with these). It's the belayer taking a snap of his mate. They're in a serious situation in rapidly deteriorating weather. Even though they're the two best climbers of their generation it could, all too easily, end in tears.
Another, even better example (which has just occurred while writing the above) is Tony Howard's amazing shot of the retreat from the Troll Wall in 1967(?) Dark figures on a rain-lashed ledge. Exhaustion setting in. German soldiers on the Russian front, brave guys who'll fight till they drop but... they're getting weaker and weaker.
And then the unforgettable feral look in Tony Nicholl's eyes. To stop him, you're going to have to cut his heart out.
He got them down. Four lives were saved. And all of it's in this (technially crap) historic, utterly iconic photo.
Mick