There is a discussion of light and composition at: http://tysonrobichaudphotography.wordpress.com/2010/01/21/a-photographic-study-in-light-rembrandt-harmensz-van-rijn-style/
While this is important, but it isn’t quite what I want to say, but nevertheless, do read it and think about it as I find this is an excellent first order approximation.
Where I differ is the ‘studio‘.
If you’re in a studio everything changes vs being on the street.
Its the ONE situation where a fixed lens is so superior to a zoom lens that nothing else count. Its the one situation where having plenty of aperture doesn’t count since you’re supplying all the light and in the place you want. Its where bokeh doesn’t count because you are supplying the background.
But I picked up on the Rembrandt because of the light and the dark.
I’ve seen some of his paintings at the Tate in London and at the Met in NYC I’ve seen others, one in particular in a private collection that is almost all dark black and brown except for the pinpoint of light catching the cheek the eye and the nose. Its fabulous. It was position in a ‘dark corner’ with a pin-spotlight on the face — all to enhance the dramatic effect of the light and dark.
The point here is Light and Dark.
It has TEXTURE.
And that’s not something most studio shots have … any way, any how.
All to many look like the shots of the the author on the back flap of a hardback book or something from a fashion magazine. Oh, and that includes the you-can-never-get-it-to-look-like-that pictures of food in adverts and on packaging.