If you are the average photo user, you probably own a zoom lens to the effect of something like 18-155 f3.5 or even 18-105 f 3.5. Have you really ever given thought to what the two ends of the zoom can do to your picture other than just zoom in and zoom out? A change in perspective can be a critical contributing factor to the entire composition as a whole.
So what is the meaning of perspective? Wikipedia defines it as –
Perspective (from Latin perspicere, to see through) in the graphic arts, such as drawing, is an approximate representation, on a flat surface (such as paper), of an image as it is seen by the eye. The two most characteristic features of perspective are that objects are drawn:
- Smaller as their distance from the observer increases
- Foreshortened: the size of an object’s dimensions along the line of sight are relatively shorter than dimensions across the line of sight
A simple method commonly employed to understand perspectives is to hold your thumb in front of one eye with the other eye closed, and to look at a large distant object such as the moon. Your thumb nicely obstructs the entire view of the moon, and this ridiculously simple logic tells us that nearer objects along the line of sight appear larger to the eye. It is the same with lenses, but different lenses work differently as far as perspectives go.
A wide angle lens has the effect of exaggerating perspectives. In other words, they make closer objects appear to be unrealistically large, with objects even a few feet away appearing unrealistically small. While this distortion of perspective could sometimes be a useful compositional element to some subjects, wide angle lenses usually do not flatter a model if you are shooting portraiture! So, the shorter the focal length, the wider is the lens and the more is the distortion it causes.
Tele photo lenses on the other hand have the opposite effect of a flattening perspective. They make nearer and further objects look less contrasting in size, which can make for some pretty awesome wildlife imagery. Have you seen images of a giant moon with a subject in front? THAT is the effect of a super telephoto lens such as a 1000mm!
Most of us are usually limited to the 100mm or 200mm range of lenses thanks to the costs associated. But you can still do a lot with an 18mm to 200mm range! The key is to select the right focal length (and thereby the right perspective) for the right subject. For instance, landscapes may warrant a wide angle lens that covers a large angle of view while it accentuates closer objects; while portraiture demands the longer range of focal lengths such as 135mm for a pleasing effect…