I'll often harangue my students about the effect a picture’s background can have on the picture's subject. Every time they set up a shot, I tell them, they need to think not just about the subject, but also about the background. Subject and background are both equally important. A bland or lousy background can hurt the subject. An interesting background can greatly enhance the subject. The photographs below illustrate different background types (click on photos to enlarge).
There are times when it may be difficult distinguishing between subject and background. This can happen where little or no distinction exists between the two. An example would be train tracks, which seem to extend towards infinity.
Then there are instances where no background exists. Or more accurately, the background is pure white. This, by the way, can sometimes be a strong selling point for those wanting to market their images. It allows the buyer to easily drop-out the white background and insert one of their own choosing.
But for the majority of pictures, there likely will be a distinct subject and a distinct background.
I was very happy with both the woman's facial expression and the way her hand and arm were angled as she held her boyfriend's hand. In addition, I think the photo is enhanced by the extra light on her face (thanks to a small hand-held flash) and with me kneeling down and shooting upward to get a more dramatic angle. But I'm pretty sure it's the vibrant sky in the background that makes this photograph pop. Think how different the impact on the subject would have been had the sky been clear blue or overcast.
As I looked through the camera’s viewfinder, it struck me that the background resembled the aftermath of a forest fire - burnt branches and scorched earth. I figured that and the bent parking sign would work well together. To me, they combine to create a dark and foreboding scenario.
I think it’s the over-exposed windows and the wall in the background that make this picture work. There was nothing extraordinary about this potted plant, which is the subject of the photograph. But by centering the windows in the frame and placing the plant directly in the middle, a satisfying balance is established. Further, the bright outdoor lighting produces the following benefits: the outside distractions are hidden by the blown- out windows, the whiteness of the windows (with the wall too) provide a clean backdrop for the leaves, and the image is pleasantly soft and mildly desaturated because of the intense exterior illumination.