Zoom lens photography is somewhat fairly understood. But, a lot of deep understanding is missed by the casual photographer. Sure, everyone knows that a wide angle lens, like a 24 mm, will cover a lot of countryside. Hence the name, wide angle. And it is relatively well understood that longer lenses, like a 150 mm produce a telephoto effect, bringing distant objects apparently much closer to the viewer.
But many shooters miss a lot of the benefits of zoom lenses. Remember, lenses do three things: they affect angle of view, affect image size, and perhaps most importantly, they can affect perspective. Lets examine three photographs of a farm house with fresh round hay bales.
The first is with a “normal” focal length lens of 50 mm. This lens produces an image size and a perspective similar to the unaided eye. But the angle of view is far from that of our eyes because we humans have such exceptional peripheral vision of 140 degrees or more.
So let’s understand what we can “see” here. First we can see several of the hay bales, we can see the house and tractor surrounded by the trees. All appear reasonably sized. The background sky takes up a nice portion of the frame. Good. But there is more to understand. Let’s look at the three “grounds”, or visual zones in this photo. The row of bales make up the foreground, the home and surrounding trees, the midground and the sky and clouds become the background. These three layers are very important in a photo like this.
The human eye enjoys this layering effect. We like to wander around in the frame inspecting what we see. But a normal lens is not our only compositional tool. We have other focal lengths at our immediate disposal. Let’s look at others.
Wide angle lens
Let’s see what happens when we change focal lengths of our lens. For this next image an 18 mm wide angle setting was used. But, more importantly, the image was composed by moving much closer to the hay bales. This did two real important things for the view: first the bales are more emphasized in the foreground, and second, the more distant home and trees of the midground became quite small. This is an effect of changing perspective. This happened because to recompose, the point of view changed and became much closer to the bales. This results in the midground and background receding and becoming substantially smaller.
In photography, perspective is a relationship of elements within the image to other elements of the image and to the frame of the image in size and apparent distance between the elements. Perspective is dependent first, upon distance to the subject and then, lens focal length. Generally, when various focal length lenses are used from the same spot, the perspective is unchanged. That is why the more creative photographers compose with their feet, not just their lens.
The next view was made with a 180 mm lens. Some would say it is a telephoto view, bringing distant objects much closer to the viewer. Here we keep the bales as foreground interest. The house and tractor are now much larger with more detail visible. And this view produces more emphasis on the foreground and midground. The background sky is less important. It is important to know that to achieve this view, the composition had to be made from much farther back than either of the two previous views.
So the lesson learned is to work every scene thoroughly. Certainly, use a variety of focal length lenses. But in addition, it is of paramount importance to vary the subject distance as well. Remember that changing the focal length from the same spot results in a different crop only through angle of view and image size. But to get the best results from any lens, you must vary the lens to subject distance.
Foreground elements are very important in composition. They anchor the scene and can be used to lead the eye into the scene. Depending upon their importance, the size may be easily manipulated through varying the focal length of the lens and most importantly, the lens to subject distance. Just don’t forget to compose with your feet instead of simply zooming your lens. Do both and your images will quickly improve.