Taking the Broad View
By Tamia Nelson
June 5, 2012
Paddling opens a window on a wider world. A world of spectacular sunsets and subtle dawns. Of deep woods and towering mountains, silver sand beaches and rocky headlands. Of shimmering waterfalls, roiling rapids, and emerald‑green surf. Of scudding storm clouds and crescent moons. Of fecund wetlands teeming with life, and families of loons diving for their dinner on lonely lakes. For all of my days, I've sought out such places. Now they're fixed on the emulsion of memory, but I often want something more tangible. That's when I pick up a brush. Or snap a shutter. And because time frequently presses, even in the backcountry, the shutter sees much more use than the brush.
Back when I made my first forays into "serious" photography, I used to haunt the post office, eager to see the fruits of my labors. But when I opened the envelope that held my slides and negatives — this was in the Age of Film, after all — I was often disappointed. To be sure, not many of my shots were out‑and‑out failures, but only a few captured the panoramic majesty of sky and water. So I went to school. Not literally, of course. Art school photography programs were well beyond my modest means. The public library was open to all, however. Ansel Adams was self‑taught, wasn't he? I figured I could choose worse role models.
Job One was learning how to capture …
The Big Picture
This turned out to be easier than I'd thought. My camera was a 35 mm single‑lens reflex. The lens it came with was designed to see the world more or less as the human eye sees it, with little obvious alteration of perspective. To achieve this, it had a focal length of 50 mm. And it was a good lens. It did a fine job with campfire scenes and other "documentary" photos, for instance. But its view of the world was far too cramped to bring the whole sweep of a wooded shore within the scope of a single shot. What I needed for that was a wide‑angle lens, and since field of view varies inversely with focal length, this meant I had to go shopping for a lens with a lower number. In the end, I settled for 28 mm. It proved to be a happy choice.
And until I entered the Digital Age, I never saw the need for anything else. When I picked up my first digital SLR, however, I yielded to temptation, acquiring a Sigma 10‑20mm wide‑angle zoom. This isn't as radical a change as it appears at first glance. Because the sensor on my digital SLR is smaller than a frame of 35 mm film, my Sigma zoom lens is the equivalent of a 15‑30 mm wide‑angle zoom on a 35 mm film camera. So I haven't entirely abandoned my old 28 mm standby. But I'm getting ahead of my story. Before we go any further, we'd better spend a few minutes to take …
A Closer Look at Wide‑Angle Lenses
Here's a little good news to begin with: You probably won't need to buy an extra lens. If you own a digital camera, whether it's a simple point‑and‑shoot model or a digital SLR, you likely have a wide‑angle lens at your fingertips already. All the digital point‑and‑shoot cameras I've seen have a zoom lens that takes you from a moderate wide‑angle view to a "short" (weak) telephoto. And most digital SLRs come with a so‑called kit lens, usually a zoom. My kit lens is a Pentax 18‑55 mm, equivalent to a 27‑83 mm zoom on a 35 mm film camera. (This can be calculated by using the applicable "crop factor," also known as the "focal length multiplier." You'll probably find it somewhere in the owner's manual for your camera.) True to form, then, my kit lens runs the gamut from moderate wide‑angle to short telephoto.
Let's see what this means in practice. With the help of a patient model, I staged a number of shots of the same scene along The River, using several lenses at a variety of different focal lengths. I picked a suitable place to stand, about 10 feet from my model, and I didn't move from that spot during the shoot. Here are the (uncropped) results:
The shot labeled "35 mm" comes closest to the perspective of the 50‑55 mm "normal" lens on an old‑style 35 mm camera. In other words, a 35 mm lens is the new normal — for my digital SLR and for many others that use the APS‑C sensor. And the extremes? Well, the 300 mm lens on my camera corresponds to a 450 mm "super‑telephoto" on my old film camera, while the 10 mm wide‑angle is best described as "ultra wide‑angle," equivalent to a 15 mm lens on a 35 mm camera.
So much for comparisons between lenses of different focal lengths. Now let's concentrate on the wide‑angle lenses alone. To begin with, these have the seemingly miraculous ability to let you get really close to your subject without losing the bigger picture:
In this shot, I was only about 10 inches from my model. (I was in no danger; he'd just eaten.) Yet the resulting portrait includes a corner of the pack he's using as a backrest, along with a good chunk of the rock outcrop on which he's sitting, as well as both the river and the woods beyond.
What are the implications for the paddling photographer? They're many and varied. For one thing, if you have a wide‑angle lens (or a zoom with a wide‑angle capability), you can grab a whole swathe of scenery in every shot. You can also get right down on your belly to shoot a photo of wildflowers and yet not lose sight of the overhanging trees. Or you can move in close to your paddling buddies and still get everyone in the picture. And this is just the start.
Of course, there's no such thing as a free lunch, is there? And building a wide‑angle lens requires certain optical trade‑offs, all of which affect the quality of the resulting image. So it's important to learn …
How to Get the Most From Your Wide‑Angle Lens
Of course, that entails understanding something about its limitations, too. As we've seen, wide‑angle lenses do two things very well: They take in a lot of the scenery with each shot, and they let you get close — very close! — to your subject without losing sight of the bigger picture. But there's a price to be paid for all of this, and one prominent item on the bill is…
Barrel distortion. Unless your wide‑angle lens is the type called a fisheye — and if you're not a pro or an enthusiast, it probably isn't — most straight lines will look pretty straight. But you can still expect to see some distortion as you move away from the center of a scene. Horizons shot at the widest angles will no longer lie flat, and trees that in life stood arrow‑straight will lean drunkenly to either side. The photo below illustrates both failings, though the compression necessary to yield a Web‑friendly image makes it hard to spot the "leaning" trees in the far distance.
The degree of barrel distortion depends on both the focal length of the lens and the distance between you and your subject. The lower the numbers, the worse the distortion. Despite appearances, the trunk of the porcupine‑gnawn yellow birch in the photo below stands tall and straight, as do the saplings in the background.
In this case, though, the barrel distortion was unavoidable, given my nearness to the birch. And it's made even more obvious by the limited depth of field I chose in order to emphasize the curls of bark and the tooth marks left by the hungry porcupine.
Is barrel distortion the only shortcoming of wide‑angle lenses? Unfortunately not. Two more problems arise from time to time:
Color gradients and vignetting. Wide‑angle lens can color your world in odd ways. Hues deepen as you move outward from the center of a photo, and a polarizing filter will make matters much worse. This is particularly evident with ultra‑wide‑angle lenses. When fitted with high‑profile filters, these lenses also exhibit pronounced vignetting, a sort of tunnel vision in which the corners and edges of an image fade to black. The phenomenon can sometimes be exploited for dramatic purposes, but most of the time it's just a distraction. If vignetting is a constant problem, you can buy less intrusive, thin‑profile filters. The cost is high, though. So I just crop shots when necessary.
Here's a photo illustrating both a strong, polarizer‑enhanced color gradient and minor vignetting at the corners:
The image quality is pretty poor, as well, but don't blame the photographer. The original is an old color side, which I copied using a home‑made apparatus. Sharpness has suffered as a result, yet the digital image accurately reflects the color gradation and vignetting in the original slide.
Barrel distortion. Color gradients. Vignetting. Surely we've reached the end of the problems that afflict the wide‑angle lens. But no, not yet. By their very nature, wide‑angle lenses see the world differently, leading to …
Distorted perspective. The name pretty much says it all.
Despite appearances, the lid on the table is a perfect fit on the Trangia burner I'm holding in my hand. Distorted perspective can be used for artistic effect, of course, and it's a convenient way to emphasize objects in the foreground of a shot. But if you're shooting close‑up portraits with a wide‑angle lens, beware! Thin folks mysteriously put on pounds, and familiar faces assume unexpected — and sometimes forbidding — expressions.
And there's one other consideration to keep in mind when using a wide‑angle lens:
High dynamic range. If a scene has both bright highlights and pools of deep shadow — if it exhibits a high dynamic range, in other words — you'll be hard‑pressed to get the exposure right. This isn't a consequence of the lens's inherent optical properties, however. It's just a byproduct of the fact that wide‑angle lenses take in a lot of country. Expose for the highlights in a chiaroscuro scene, and some parts of the resulting photo will look as if you were shooting in a mine shaft without a flash. At the other extreme, with longer exposures, much fine detail will be lost in a brilliant wash of light. A graduated neutral‑density filter can help in some situations, as can shooting multiple exposures from a tripod and then combining them in the digital darkroom in a procedure called HDR processing. Or you can take the easy way out. Make a virtue of necessity and let the contrast work for you, rather than fighting it.
I hope this long list of caveats and cautions hasn't dampened your enthusiasm. Taking the broad view makes a lot of sense for backcountry photographers who want to limit the size of their photographic kit. And here are some hints to help you use wide‑angle lenses and zooms to best advantage:
Get hyper(focal)! Wide‑angle lenses combine great scope with a deep depth of field. That's a big help if you have to snatch a shot in a hurry. Each aperture has a hyperfocal distance. Focus your lens for this distance, and everything from that point out to the horizon will be acceptably sharp — so long as the aperture remains unchanged.
That's one way of looking at things, at any rate. Unfortunately, there's an alternative definition of hyperfocal distance, similar to the first but not identical, and this second definition often yields a slightly different value. And then there's the question of when, exactly, an image is "acceptably" sharp. But — this is the good news — these are quibbles for experts. For the rest of us, it's enough to say that you won't go far wrong if you set your camera at ƒ/8 in aperture‑preferred mode, prefocus on something at the hyperfocal distance (see your owner's manual to learn what this is), and then fire away with confidence. This confidence will only rarely be misplaced.
On the other hand, there are times when you won't want the great depth of field that an aperture of ƒ/8 gives you: if. say, you need to eliminate distractions and direct attention to your primary subject. Then you'll have to open up your aperture as far as it will go and focus accordingly. Just remember that hyperfocal distance depends on aperture.
One more thing: In opting for the broad view, you'll also need to take care not to …
Shoot yourself in the foot. Wide‑angle lenses make this easy, and while the consequences aren't quite as dire as they would be if you let off a holstered Glock at half‑cock, they can still cause embarrassment. (NB Sticklers for accuracy will be quick to point out that a Glock doesn't have a half‑cock notch, and that its integrated trigger safety mechanism is state of the art, making accidental discharges of any sort extremely unlikely. But I liked the word‑play.)
And then there's this:
Wide‑angle lenses just aren't for the birds. Not unless you get very lucky, at any rate. Take another look at the elusive leopard in the photos at the start of this article. See how he disappears as you bring the focal length down? Unless you're photographing elephants, you'll find it hard to catch wildlife on the move with a wide‑angle lens. There's a mixed flock of ducks and geese in the picture below. Can you find it?
I can't either. But the geese and the ducks were there, clearly visible in the distance. A wide‑angle lens simply wasn't the right tool to bring them in. Still, fortune sometimes smiles. As it did when another flock of geese took flight from beyond the reeds just as I was framing a shot:
There's not a great amount of detail in the photo. It's backlit and there was a lot of haze in the air. But the birds make the picture work. (I also cropped the shot to tighten up the composition). The verdict? All in all, a wide‑angle zoom — or a fixed‑focus wide‑angle prime lens, for that matter — is a pretty good bet for backcountry travelers, even if it's the only lens in your bag.
Zoom lenses spare modern paddlers many of the hard choices that confronted waterborne shutterbugs only a few short years ago. A single lens can now do it all, or mostly all, spanning the range from wide‑angle to telephoto in a compact (and inexpensive) package. But how many of us make the best use of these little marvels of technology? For instance, are you satisfied that you're getting the most out of your camera's wide‑angle capability? If not, make a special effort to take the broad view on your next trip. That's my suggestion, at any rate. Give it a try and see what you think.
- My Backcountry Photography series at Paddling.net
And an article from my own website:
Plus a look at what wide‑angle lenses can do in the hands of some skilled shooters:
- "The Sigma 10‑20mm Club"
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