Expand Your Horizon
Ultra Wide Zooms Can Do The Trick

At the shorter focal lengths of an ultra-wide zoom lens, the extremely wide angle of view is useful for including very large areas. The "look" of the image is also distinctive, offering a more dramatic effect than a 28mm lens. (At 20mm; f/16; B+W polarizer; Fujichrome Velvia.)
Photos © 2000, Peter K. Burian, All Rights Reserved

Although the 28-80mm zooms have become the standard lenses, they're not ideal in every respect. Although practical their somewhat limited focal length range tends to yield an "average" vision of the world, perhaps limiting the ability to see in more creative ways. If you assume this is the range to use you are certainly missing out on those lenses that yield the powerful effect of a more dramatic perspective. And they are of little use in situations where you simply cannot back up far enough to include the expansive sweep of an entire panorama.

Enter the new breed of zooms that incorporate a much shorter focal length, some as short as 17mm. Capable of producing high visual impact with an ultra-wide angle of view, such zooms can be useful for making images that captivate viewers. If you want to expand your horizons and are willing to experiment, one of these ultra-wide zooms can open new doors to creativity.

The expanded spatial perspective and extensive depth of field provided by a very short focal length can make for interesting landscape images. For a classic landscape, try to include subjects at various distances from the camera. (Tokina 19-35mm zoom at 19mm; B+W polarizer; f/16; Provia 100F.)

Ultra-Wide Characteristics
A 28mm lens offers an angle of view of around 75°, roughly comparable to that of your own eyes. By 20mm--the first step into the realm of the "ultra-wide"--the angle of view increases to an impressive 94°, recording substantially more elements of any scene. Still not wide enough? Then switch to a 17mm focal length with one of the "widest" zooms in our chart for an incredible 104° angle of view.

Besides "seeing" far more than your eyes can without scanning, very short focal lengths have other characteristics. First is the "lengthened" perspective: actually an optical illusion producing apparent distortion of the relative size of objects within a scene. Those in the foreground become unusually prominent, overpowering the scene, at an apparent size far beyond the norm. Meanwhile, anything at a greater distance is "pushed back," rendered much smaller than the eye perceives.

Exploit these traits with railway tracks or a highway receding rapidly toward the horizon. Or use them for tight close-ups, lending a sense of intimacy to the primary subject. A group of wildflowers for instance, with an expansive sweep of blossoms as far as the eye (or lens) can see, makes for an appealing picture. A single stallion, looming in the viewfinder, will seem larger than life on film. Contrast his dominant position with that of the brood mares; although only 10' back, they appear distant, taking a smaller, secondary role in the image. This distortion of relative size of objects is created by something called "expanded spatial perspective."

Using this exaggerated near/far relationship, you can make a small cabin seem more spacious, while a desert vista, or lush farm field, becomes more expansive, ideal for an interpretive (instead of documentary), depiction of reality. Tilt the camera upward to include an entire building and another trait becomes obvious: keystoning, or converging verticals making the structure appear to lean backward. This linear distortion occurs because the base of the building is closer to the lens than its top. Fail to keep the film plane parallel to most subjects and the perspective will seem unusual. Vertical lines will seem to converge or lean inward out of plumb, while the edges of the horizon bow upward.

Note, too, that short focal lengths can produce extensive depth of field. Move farther from the subject, set f/22 and use the focusing technique described later and you can expand the zone of apparent sharp focus significantly.

In order to exclude competing elements from a wide angle composition, move as close to the primary subjects as possible. Sometimes, a very high or very low viewpoint can also be useful. (At 24mm; f/8; Fujichrome 100MS.)

Ultra-Wide Techniques
Portraiture aside, many distinctive images can be made at the short end of an ultra-wide zoom. Consider the following techniques as a starting point.

Move In
An extremely wide angle of view is likely to record multiple elements, which will compete for viewer attention. This may create a photo without a clear message or sense of purpose. Move in closer to exclude extraneous details. Fill the frame with a few desired objects that have some logical relationship to the primary subject.

For a fairly accurate rendition of lines within a scene, hold the camera back parallel to the subject to minimize linear distortion. For maximum depth of field, focus on the hyperfocal point; frame tightly to avoid including extraneous elements. (At 21mm; f/8; B+W polarizer; Fujichrome Provia 100F at EI 200.)

For the most accurate rendition of buildings and trees, hold the camera level, so the film plane is perfectly parallel to the subject. This will prevent keystoning: converging verticals. Unfortunately, you may then find an excessive amount of foreground detail in the frame. Crop such extraneous elements when making (or ordering) prints, or afterward with scissors or digital imaging.

Reduce Flair
Avoid shooting into highly reflective surfaces (such as water on a brilliant day) as this can create flare. Use a lens hood on bright days. If flare is noticeable on the viewing screen, change your shooting position; try to compose so that some object (such as a tree) will block the sun.

Lens Selection Criteria
When shopping for an ultra-wide zoom lens, consider the following criteria before deciding as to which focal length and model would be right for you.

Maximum Aperture: A wide, f/2.8 aperture is essential for photojournalists shooting with available light and for situations where flash and tripods are prohibited. However, even f/4-4.5 is adequate for most other applications. After all, we generally want maximum depth of field with wide angle lenses. Hence, they're typically used at small apertures such as f/11 or f/16, for an expanded range of sharpness--in a cityscape or group photo of the entire high school football team.

Since we often use ultra-wide lenses at small apertures for increased depth of field, a "fast" zoom is rarely necessary. Naturally, high quality optics--aspherical or conventional--are useful for maximum edge-to-edge image sharpness. (At f/11; B+W polarizer; center-weighted meter at +1 compensation; Ektachrome E100VS.)

Secondly, most anyone can hand hold a 20mm focal length at 1/30 sec and still get sharp pictures, so there's less need for a "fast" zoom. Finally, models with smaller maximum apertures are also a lot more compact, lightweight, and affordable.

Premium Grade Optics: Some of today's ultra-wide zooms employ one or more elements with a non-spherical surface. Called "aspherical" these correct for "spherical aberration": an optical flaw that causes light rays entering through the edge of a lens to converge on a point different than those passing through the center of the lens. The aberration is commonly corrected by combining a convex and concave element to cause all light rays to focus on a common plane. With wide angle lenses of moderate maximum aperture the conventional technique is generally adequate. Stopping down to even smaller apertures pretty well eliminates the problem, as the amount of light entering near the edges is minimal.

With "fast" lenses such as f/2.8, the most effective method for compensating spherical aberration at wide apertures is achieved through the use of aspherical elements. One or more of these will also better correct for "barrel" distortion: the bowing outward of lines near the edges of the frame. Because a single aspherical element can take the place of two others, the size and weight of the zoom lens can be reduced. Recently developed technology allows for affordable manufacturing of aspherical elements with glass molding, or by, bonding other materials to the glass to form the non-spherical surface.

Internal Focusing: As indicated in our chart, some of the ultra-wide zooms incorporate an inner focusing system; instead of moving the entire optical assembly, only one or two groups of elements are shifted when focusing. This is claimed to provide faster autofocus operation and, in some cases, better image quality in extreme close focusing. Also, the front element does not rotate so you can adjust a polarizer before or after focusing; its effect will not change.

Close Focusing: A minimum focusing distance of roughly 18" will meet most needs, but if you want to get particularly creative, with extreme close-ups, look for a model that will focus even closer. However, remember that apparent size distortion (discussed earlier) is most pronounced when the subject is extremely close to the lens. Take a close-up portrait for example, and the subject's nose will appear huge while his (more distant) ears will appear to recede into insignificant size.

In order to add a feeling of depth to this image, I decided to include the foreground grasses and the distant shore. For extensive depth of field, I set the point of focus at a point roughly 1/3 of the way into the scene. (At 24mm; f/8; handheld; B+W polarizer; Fujichrome Sensia II 100.)

Maximize Depth Of Field
For the greatest depth of field at any f/stop, you usually set focus for the hyperfocal distance using the scale on the lens barrel. Frankly, this technique (often described in books and magazines) is complicated with a zoom lens, and few zooms even include such scales.

There is a solution to this problem: refer to published specifics as to the right focused distance for maximizing depth of field. I use Steve Traudt's Hyperfocal Chart which provides the hyperfocal distance for apertures from f/8 to f/32 for focal lengths from 14-75mm. For example, if shooting at 20mm at f/22, set focus manually to 3' for a range of sharpness extending from 1.5' to infinity. (Contact Traudt at synvis@gj.net or (970) 245-6700 or check his web site at: www.synvis.com)

For a quick alternative, simply focus at a point roughly a third of the way up from the bottom of the frame; a mountain landscape, field of wildflowers, entire church interior, etc., can be rendered within the zone of apparent sharpness even at mid-size apertures at the wider focal length ranges of an ultra-wide zoom.

Because the sun appears as very small in a wide angle image, it can often be rendered as a sunstar at small apertures. If necessary to avoid flare, compose so part of the sun is hidden behind some object. (At 24mm; f/22; Fujichrome Sensia II 100.)

For a dramatic effect, try intentionally exaggerating the linear distortion by shooting from ground level, tilting the lens upward on a steep angle with a group of skyscrapers, a huddle of football players, or the interior of a stadium. The resultant unconventional perspective can add a lot to personal or interpretive images.

Watch For Vignetting
Light falloff (darkening near the edges of the frame) is common to some extent with most ultra-wide zooms at wide apertures. When a subject of one color (sky, building, etc.) fills the frame, stop down to f/8 or f/11 to eliminate this problem. When using a polarizer at 24mm or shorter focal length, check the viewing screen carefully--with depth of field preview--at the actual shooting aperture. At f/11 to f/22 especially, darkening at the edges of the frame may be visible, unless you use a "thin ring" filter designed specifically for ultra-wide lenses. At an ultra-wide angle of view, not all of the sky will be evenly darkened by a polarizer; if necessary, switch to a longer focal length or remove the filter if the effect is unnatural.

When using a focal length shorter than 24mm with filters, vignetting of the image can be a problem. Check for vignetting--with depth of field preview at f/16--when stacking two filters, using a rectangular filter holder, or a polarizer with a thick ring. (At 19mm; f/11; polarizer; Fujichrome Provia 100F.)

Exploit Flare
If a small part of the sun is still visible, stop down to f/16 or f/22 to render it in a manner resembling a star. This can make for a pleasing accent in a landscape photo. Check the effect with the depth of field preview control if your camera is so equipped.

An extremely wide angle of view does require some experimentation for creating effective images, so practice, search for suitable subject matter and try unusual viewpoints to exercise your creativity. Some of the pictures will seem distorted or unnatural but others will be dynamic or dramatic. Whether for unique photographs or for problem solving in tight quarters, an ultra-wide angle zoom will surely open your eyes!

Share | |

Enter your Shutterbug username.
Enter the password that accompanies your username.