The Tuesday Composition: Telephoto Compression

Layers, Yosemite National Park, California

Layers, Yosemite National Park, California. A classic viewpoint, 300mm focal length. While we intellectually understand that the elements of this image are at quite different distances from the camera, telephoto compression seems to take away some of the cues our brain uses to perceive depth.

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Just as I often turn to wide-angle lenses when I want to create images with a sense of depth and perspective, when I purposefully want to lose a sense of depth, when I want to compress elements of an image in order to abstract or combine them, then I’ll often look to the longer end of my over-abundant collection of lenses.

First, it’s worth acknowledging that, pedantically, telephoto lenses don’t change perspective (warning: PDF document).  Seen from the same point, two objects will change in size, but proportionally, when you change lenses. Of course, if you change your shooting position to compensate for the new focal length, that’s a different matter entirely. So I’ll avoid saying that telephoto lenses change the perspective in a scene.

But there is a real, identifiable “look” to images we extract out of a scene using a long telephoto lens. We often talk about telephoto images as looking “flat” or “compressed”, these images do not seem to trigger our visual system into perceiving an illusion of depth in the image the way that many wide-angle shots do. Where does that look come from? I believe it primarily comes from two factors.

First is this matter of shooting distance. If we shoot along a row of pickets in a fence, and we’re close to the fence, the distant pickets will appear a lot smaller in the frame than the nearer ones will. As we’ve described above, to make a similar shot with a telephoto lens we’ll move farther from the fence, leaving the pickets more similar in size when we do photograph them. When the pickets vary in size, our brains actually are able to make use of that information, we really do perceive a sense of depth there. Even when the objects in the scene are quite different; if we’re familiar with the real-world scales of the object in a scene our brains will do a great job of interpreting depth based on that information.

Midnight Dusk, Látrabjarg, Westfjords, Iceland. Effective focal length: 420mm.  The effect of miles of air is part of the flattening in this image.

Midnight Dusk, Látrabjarg, Westfjords, Iceland. Effective focal length: 420mm. The effect of miles of air is part of the flattening in this image.

Second, in photographing distant objects in a scene, the effects of haze often seem to play a part in our perceptions as well. In looking over series of distant mountain ranges, haze may reduce the contrast to the point where we see little detail in the scene, except for edges between those ridges, reducing the image to an almost cartoon-like character. This is a great tool for simplifying and abstracting an image.

There are limits to this trickery, the primary one comes from depth-of-field. If our goal is to remove depth from a scene, we need the elements in it to all be in pretty sharp focus. Telephoto lenses, all other things being equal (same shooting distance, same sensor pixel size) will keep a smaller range of distances in the image in acceptable focus. (But mind the way I’ve said that, if you frame that question differently, you get a different answer.) In some scenes it can be impossible to get everything in focus, even at f/22 or f/32. Even if you can get everything in focus at f/32, the long shutter speeds you might need to compensate might leave unable to create the shot you envisioned.

Despite these limitations, telephoto compressions are a fun, easy way to create wonderfully abstract images, particularly with distant objects that form a sequence or pattern. Give one a try!

Comments

  1. “Despite these limitations, telephoto compressions are a fun, easy way to create wonderfully abstract images”

    Except they’re not abstract at all, because they’re no different to the way your eye would see the scene. It’s just they’re enlarged. The perspective is the same. So they’re not abstract by default.

  2. “Except they’re not abstract at all, because they’re no different to the way your eye would see the scene”

    That doesn’t, to my mind, follow. Perhaps you are using the word abstract differently than I am, it has several meanings.

    It’s perfectly possible to create abstract images at almost any focal length of course, through a variety of techniques that create images that are difficult to interpret in terms of realistic three-dimensonal objects, and instead take on the a more two-dimensional perceptual character. I believe that our “sense” of depth in an image is a complex perceptual function of many sources, not just parallex but depth-cuing in haze, the presence or absence of shading that reveals form, and so on. Creating images that intentionally avoids the inclusion of those cues is a form of abstraction, just as any photograph is in part an abstraction by virtue of the fact that it both includes and excludes (based on where the camera is pointed, etc.)

    It is my observation that often telephoto “compression” images often seem to exhbiit this “flat”, “depthless” character, a character seen more easily in the second image than the first. In the second image, you’ll note the lack of concrete detail in the ridges, a lack that wouldn’t be present if we moved close enough to those ridges for objects half the height of the picture to really fill half my field of view.

    As I identified in the paragraph beginning “secondly”, I think that the contrast-reducing effects of haze are a part of this, but suspect that there’s more to it than that.

    It’s not just haze, though. With a telephoto perspective distant objects of similar size are rendered at a similar size on the image–in short, at long distances there’s very little perspective, and telephoto images (of distant objects) thus are robbed of perspective depth-cues that create a “sense” of depth in a two-dimensional image. I believe that factor is also playing into the first image.

  3. PS: Mike, thanks for the thought-provoking comment!

  4. Interesting views on that!

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