There are two sides to photographic creativity. The first lies within your psyche—that intangible, indefinable thing that makes each of us unique. The other side is far more concrete and stems from understanding some basic technical principles. Comprehending these concepts allows you to use your tools—your camera kit, essentially—in a way that will allow you to exploit that first thing (i.e. your individuality). So let’s engage in a bit of tech talk.
Some novice photographers have the misconception that the fundamental settings of aperture and shutter speed are merely means to establish exposure. It’s the “merely” in that sentence that represents the misunderstanding because these settings—along with ISO, parts of what I call “the exposure triad”— do, in fact, establish exposure. And there’s no question about it—establishing a desired exposure is part of the creative rendering of subjects. A classic example is whether to represent a subject as a silhouette, or to retain detail in a comparatively dark subject; with the dynamic range that modern digital sensors are capable of, this is very much a creative decision.
But there’s far more to it than that. For instance, assuming an ISO of 100, the following two shutter speed/aperture pairings will result in the exact same exposure of a scene:
f/2.8 @ 1/250 sec.
f/16 @ ¼ sec.
But, depending on the scene, your proximity to it and the focal length of the lens you’re using, though the exposure is the same, these two pairings will result in entirely different images of many, many different subjects. This is the case because aperture is a critical factor in determining depth of field and shutter speed is a critical factor in determining how non-stationary objects appear.
As you reduce the size of the aperture (i.e. as the f-number increases), depth of field increases, all other things being equal. (Sharpness may or may not increase, depending on the specific optical qualities of the lens and the ramifications of diffraction, but that’s a story for another day.) How much of the image you desire to be sharp is a creative decision. You may want everything sharp; you may only want certain parts of the frame to be sharp. Understanding how aperture impacts the desired depth of field in addition to the desired exposure will help you implement your creative vision.
You can imagine how different an image will appear depending on the available depth of field—which, again, is dependent on the chosen aperture.
The shutter speed dimension is even easier to understand. When it comes to moving objects, the faster the shutter speed the more likely a moving object is to be displayed as “frozen.” How moving objects—be they animals or water or foliage or whatever—are rendered is obviously a matter of creative license and your choice will have a huge impact on the final presentation of the image.
Unlock your personal creativity by understanding the technical nuances that form the keys to implementing these facets of your vision. Aperture and shutter speed play important roles in exposure, but that’s not the end of the story. Take full creative control by establishing these settings yourself.
Thursday Tips is written by Kerry Mark Leibowitz, a guest blogger on 1001 Scribbles, and appears every other Thursday. To read more of his thoughts on photography, please visit his blog: Lightscapes Nature Photography.