Tuesday, March 2, 2010
Go Ultra Wide!
Composing successfully, controlling distortion and choosing the right lens for stunning wide-angle perspectives
Ultrawide lenses are usually defined as lenses 20mm or shorter in full-frame 35mm-film-equivalent terms. That usually means 18mm, 15mm or even 12mm, but it’s not just about the focal length—you also have to account for the sensor size. On smaller sensors, ultrawide status requires even shorter lenses, down to as small as 7mm, which translates into a solidly ultrawide 14mm equivalent when used with a Micro Four Thirds system camera.
Fisheye lenses also are ultrawide lenses, but not all ultrawides are fisheyes. Fisheyes have an angle of view approaching 180 degrees—enough to take in the “whole sky.” Fisheyes are most often recognizable for their dramatic barrel distortions that curve straight lines around the center of the frame. Most ultrawides, though, aren’t quite so extreme. In its ideal form, an ultrawide lens is rectilinear—designed to keep straight lines straight.
Even though ultrawide lenses are usually designed to minimize distortion, they still can be difficult to use. Getting close can be an effective way to use an ultra-wide, placing a focal point right up front in the composition. The lenses also can be used to fit large subjects into the small frame. This type of composition requires even more care to avoid disappointment.
For example, it’s easy to see how a telephoto lens compresses the scene, shrinks the depth of field and generally isolates the subject to create simple compositions free of distractions. But just as telephotos show a little, ultrawides show a lot—sometimes too much. If you’re not careful, your scene can be full of extra information and distractions that make for a less cohesive composition.
Even more than compositional challenges, the biggest mistake new ultra-wide shooters make is that they’re not careful with the precise positioning of the camera. Small movements make big changes to the composition, even creating significant optical distortions.
Every tilt and twist of an ultrawide lens creates massive changes to the lines in your composition—including walls, doorways, trees and people. That’s how you end up with photographs in which parallel subjects such as buildings and trees diverge within the frame, seemingly pointing in different directions. For parallel lines to remain parallel, there’s one trick that always works: Keep the camera’s sensor parallel to those lines.
For example, when working in a confined room with the camera positioned level (and therefore parallel with walls, doors and people), the lines in the scene won’t diverge. Tweak that camera position just a bit, though, and watch the scene go haywire. Unless you’re deliberately trying to use those divergent lines as creative compositional elements, if you want the straight lines to remain parallel, you must keep the camera level.
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