Controlling perspective

It used to be said that the camera cannot lie, but using different focal length lenses you have almost as much freedom to control perspective in a photograph as an artist has when drawing by hand. Perspective is an important way of implying depth, as well as height and width, in a two-dimensional picture. A photograph of a scene such as a landscape shows elements smaller and closer together towards the far distance, and parallel lines seem to taper towards the background. The more steeply such lines appear to converge (the greater the difference in scale), the deeper a picture seems to the eye and the greater visual depth.

As Figure 15.8 shows, it's all a matter of relative distances. Suppose you photograph (or just look) at someone from a close viewpoint so that their hands are only half as far from you as their face. Instead of hands and face being about equal in size, normal human proportions, the hands look twice as big.

Perspective is steep. But if you move much further back, your distance from both hands and face becomes more equal. Hands are only 1.2 times as big as the face. Perspective is flattened. Of

Figure 15.8 Whether drawing or photographing, a close viewpoint gives the steepest perspective (change of apparent size between nearest and furthest elements). Moving back reduces this ratio of nearest and furthest distances, flattening perspective.

Ratio 1:2

Figure 15.8 Whether drawing or photographing, a close viewpoint gives the steepest perspective (change of apparent size between nearest and furthest elements). Moving back reduces this ratio of nearest and furthest distances, flattening perspective.

Close, with wide angle lens

Ratio 1:1,2

Close, with wide angle lens

Close viewpoint

Distant viewpoint

Steep perspective

Flat perspective

Steep perspective

Flat perspective

Ratio 1:1,2

Distant, with telephoto lens

Distant, with telephoto lens

Figure 15.9 Changing both distance and focal length.
Figure 15.10 Changing both distance and focal length.

course, being further away too, everything is imaged smaller - but by changing to a longer focal length lens you can fill up your picture again.

So to steepen perspective the rule is to move closer and then get everything in by either zooming to wide or changing to a wide-angle lens. A shot like Figure 15.9 makes you feel close to the person with the hat and distant from the cottage across the river. It was shot using a 35 mm lens with the camera some 10 m from the fenced tree. In Figure 15.10, the camera was moved to three times this distance and then the lens changed to a 100 mm to restore the tree to about its previous image size. But look what has happened to the cottage and the seated figure! There is now much less scale difference between foreground and background elements. With the camera further away, perspective has been flattened (painters would call this 'foreshortening') and the photograph has a cramped-up feel. Figure 15.11 also makes use of this foreshortening technique to flatten the distance between the two buildings in the picture.

Extremely short or long focal length lenses give results so unlike human vision they are really special effects devices. Figure 15.12, shot with an 8 mm fish-eye lens on an SLR, demonstrates its extreme depth of field as well as plenty of distortion (the building behind was one long straight wall). Lenses of this kind are very expensive, but lower cost 'fish-eye attachments' that fit over the front of a normal lens provide a more affordable option.

Figure 15.11 Longer lenses flatten the distance between the subjects in a scene. Here the buildings almost look as if they are sitting right next to each other rather than across the street.

Figure 15.11 Longer lenses flatten the distance between the subjects in a scene. Here the buildings almost look as if they are sitting right next to each other rather than across the street.

Figure 15.12 Fish-eye lenses (or lens attachments) provide a highly distorted view of scenes that with some lenses equals a 180° view. Notice also the large depth of field produced by virtue of the fact that this is an ultra-wide-angle lens.

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