Let’s get past the notion that long lenses are just for bringing distant objects close, and wide lenses are only for taking in wide views or for use in close quarters. To begin with lets think about some differences between human visual perception, and the way your camera “perceives” the world
Human Vision vs. Camera Lenses
Your human visual system sees the world quite differently than your camera sees that same world.
If you sit and concentrate on a subject in front of you, there is portion of your total field of view, directly in front of you in which you have maximum visual acuity. This area of maximum visual acuity represents a field of view of about 18 degrees, give or take, in most people.
Beyond this, there is area in which you can clearly take in everything happening without turning your head, representing a field of view of about 45 degrees. If something captures your attention at the edges of this area, you will be inclined to turn your head to look at it more closely. Beyond this “single glance” area, is your peripheral vision, in which most people become aware of objects (particularly if they are moving) out to about 160 – 170 degrees.
Another feature of your human visual system is the ability to completely focus your attention on something, and ignore other objects in front of you. At times this trait is so strong that we literally don’t see something that is right in front of our faces.
Now, a camera lens does not possess either of these traits. Instead of our “variable field of view” (to stretch the concept a bit), a camera lens sees in any instant, only with a fixed field of view, depending on the lens you have chosen. Also in contrast to your visual system, a camera lens does not possess the ability to selectively focus its attention on something, and “not see” something else. Camera lenses are “all seeing eyes”. As photographers, it’s important to be aware of this, since anything in our viewfinder will record in the image; whether we want it there or not. Knowing this we have to always be careful to examine everything in the viewfinder, and if it’s something that doesn’t add to our image, we will need to take steps to remove it, or at least de-emphasize it. We could do this by choosing a different point of view or a different lens, or by minimizing depth of field by choosing a wider aperture.
Lens Choices for Photographers
Lenses fall into three broad categories: Wide-angle, Normal and Telephoto. Wide-angles take in more than a Normal lens’s 45 degree field of view; that is more than our human “one-glance” field of view. Telephotos on the other hand see less than our “one-glance” field of view. These field-of-view differences provide the photographer with two powerful creative abilities:
· Altering apparent perspective
· Background control
In our photographic context, “perspective” refers to the ability of lens to alter the apparent “near-far” relationship between objects in our images.
Perspective and Background Control:
Here’s an important point to think about. Understand this, and you’ll be a long way towards understanding how to use your lenses creatively.
The common understanding is that big telephoto lenses are used to bring distant objects closer, and that wide–angle lenses are used to take in “wide” vistas. Sure… these lenses can be used for these purposes, but to think of these different lenses in only this way is to severely limit the creative possibilities available to you. The most powerful advantage that these different lenses give you is the ability to change the relationship between the subject and the background and to control what stays or goes from your backgrounds. (Side note: Attention to, and the ability to control background elements is one of the key differences between accomplished photographers and beginners.)
In each image here, I attempted to maintain roughly the same subject size in the viewfinder. This meant that with the 24 mm wide angle I was much closer than with the 200mm telephoto.
Notice how, even though the subject size is roughly the same in each image, the wide angle lens takes in much more of the background than does the telephoto. Wide-angle lenses require greater care when composing images since it is all too easy to include some unwanted or distracting element in the background. Telephotos on the other hand, allow the photographer to more easily control what remains in the background of his or her image.
Notice also that the wide angle seems to expand the apparent distance between the subject and the background elements, whereas the telephoto seems to bring the subject and background closer together: this is the so-called telephoto “compression effect”.
200mm lens (APS-C = 135mm)
Going back to the wide-angle image, notice how the girl’s arm and particularly her elbow seem unnaturally large in relation to the size of her head. In the 70mm image and to an even greater extent in the 200mm image, the size relationship seems much more natural. Here is an example of an undesirable effect of the wide-angle lens’s tendency to stretch the apparent perspective in an image. Since most people would not usually accept this type of distortion as attractive or desirable, tight portraits of people are best left to lenses of about 85mm and up.
Changing to way you think of and use you lenses, paying attention to your backgrounds, and how you want to render the relative size and spatial relationship between your foreground and background elements will help you to add real impact to your images.