Throughout the day light changes. Through out the year. It depends on the weather. Man made lighting. All to be considered.
Shutter speed. ISO. What kind of image do we want? What do we see in the viewfinder? What do we want the image to be? This is another tool.
Spent some time looking at images by Robert Frank. They are b&w so some qualities of light are missing but we can see how he creates images that are light and dark and that this is another tool. That he uses light to create the image. As with composition, form, colour etc we make choices that strengthen or weaken an images or bits of an image. In “Car accident – U.S. 66, between Winslow and Flagstaff, Arizona” the images is light, almost over exposed. This isolates key figures, reduces others, the background and even the body. The image is two men staring at a blanket covered body. The grass, the buildings, the people talking are reduced and pushed into the distance. There is darkness upon a white background. The subject is dark but the image light. He is aware of the role of light and plays with it and to good effect.
These are our choices. How do we want the image to look? We have to make these choices!
PS: The copies of the photo on the net seem to appear with many qualities. This one seems close to the book, but really that’s the place to look.