From Amy Touchette’s article “Street Photography: How to See and Use Daylight Creatively” for tuts+:
As many of you might know, the etymological roots of the word “photograph” are the Greek words for drawing (-graph) and light (photo-). That means without illumination of some sort, a photographic subject can’t exist.
Finding a workable source of light is not the only concern photographers have, of course. But it’s the foundation of the medium, and when you’re out on the street during the daytime (we’ll talk about nighttime light another time), the light can be as difficult to harness as a compelling subject, given we have so little control out there.
Interesting subjects can be found anywhere, at any time. Will you be poised and ready when they cross your path? And if you are, will the light be “right” enough to show what’s captivating about your subject? Making an extraordinary photograph marries the two seamlessly.