The Far‑Seeing Eye
Focusing on Monoculars
By Tamia Nelson
October 9, 2012
The human eye is a wondrous thing, but it has its limitations. Just ask any birdwatcher. There's a good reason why twitchers are almost always pictured holding binoculars. And it's not just twitchers. Paddlers, too, frequently find that their Mark I eyeballs need a little help. Here are a few for‑instances: Is that hazy gap in the tree line a blind bay, or is it the outlet you've been looking for all morning? Is the clearing that's just visible on the far shore of the lake a fire scar or the head of the portage trail? And what about that dark mass rising out of the water in the rapids ahead? Is it a boulder? Or a patient, if somewhat peckish, momma grizzly, waiting for a meal to drift her way? You'll want to know.
In cases like these I reach for my binoculars. To be sure, if I happen to have my camera handy, and if my long telephoto lens is already fitted, I could use that to extend my eyes' reach, instead. But I don't often keep my camera around my neck when I'm on the water. And the camera's little LED display is no match for the crystal‑clear image I get when I look through a good pair of binoculars.
Luckily, I own two very good pairs. The original black finish on my old Bushnell 8 x 36 Audubon binoculars may have worn away in many places, but the optics are as sharp as they ever were. And my little Bushnell 7 x 26 compacts are unequalled when it comes to bringing nearby objects even closer — something I often have to do when I'm trying to identify an elusive warbler in dense cover. I also have a dirt‑cheap pair of Tasco 8 x 21s that long occupied a berth in a PFD pocket. They couldn't match the performance of either pair of Bushnell binoculars, however, and the Tasco's individual focus was a perishing nuisance when I was in a hurry. But at least they wouldn't have set me back much if I happened to go for an unplanned swim. They were also very light and wonderfully compact.
Still, I often found myself wishing for something even lighter and smaller. And the answer had been staring me in the face for quite a while:
As the name suggests, a monocular is just one‑half of a pair of binoculars. Or to put it another way, a monocular is the compact offspring of the ancient mariner's spyglass, though modern optics yield better performance (higher magnification, greater eye relief, and a wider field of view) in a much handier package than any spyglass. And since a monocular is, in effect, half of a pair of binoculars, it also weighs only half as much as its double‑barreled cousin, while taking up only half as much space in pack or pocket.
Of course, you lose something in the process. The world seen through binoculars is vividly three‑dimensional, and finding your target is almost as easy as it is with the naked eye. By contrast, the monocular world is flat, and until you get the knack, you'll often come up empty‑handed in your search for whatever it is you're trying to get close to. But don't make the mistake of selling monoculars short. Once you adjust to their limitations, they have a lot to offer go‑light paddlers — not to mention walkers and cyclists. In fact, it was Farwell who first convinced me to give monoculars a try, and he first discovered their virtues when he was on his bike. Here's how it happened: Farwell's vision isn't what it used to be. One eye is nearly useless — he calls it his "motion sensor" — and the other is slowly going the same way. Happily, he still sees well enough to paddle a canoe and ride his bike on amphibious sorties, though he admits he did get a bit of a start recently when he mistook a yearling bear for a large dog. He has trouble reading road signs, too. So he started carrying binoculars in his bicycle's bar bag, snatching them out whenever he needed to decipher the faded legend on a birdshot‑peppered signpost. Then it occurred to him that a one‑eyed man had very little use for binoculars. So he bought a cheap monocular.
It bore the legend Alpen 10 x 25, and while its eye‑relief was marginal and its low‑light performance was poor — no surprise, given the 2.5 mm exit pupil — it did the job. Now Farwell could read signs without having to walk across the road. And he soon found himself using the Alpen on the water, as well. His Zeiss 10 x 40s are immeasurably superior in almost every way, obviously, but he often hesitates to use them afloat. He felt no such qualms about putting the Alpen at risk, however — and his pack was lighter by a good two pounds, into the bargain.
So it's also no surprise that, before long, the Alpen monocular became his constant companion. And it served him faithfully. That said, he found its relatively long minimum focus distance (18 feet) to be frustrating at times, and he began looking around for something better. He didn't want to spend a lot of money, though. After all, the Alpen's low cost was among its greatest virtues. And as it happened, price was the first thing that drew Farwell's attention to the Alpen's successor:
The Carson 7 x 18 Close‑Up
It was cheap. It cost no more than the Alpen. But the optical quality is good, yielding a bright, crisp image, and the eye relief, while certainly not generous, is at least equal to that of the Alpen — a matter of some importance to any eyeglass‑wearer. Soon the Carson had replaced the Alpen as Farwell's boon companion, and before long he was preaching its virtues to anyone who'd listen. I heard what he was saying, and I bought one of my own. You can see it in the photos below, displayed alongside my Bushnell 8 x 36 Audubons, my Tasco 8 x 21s, and Farwell's Alpen monocular. And yes, the Carson is the smallest thing in the picture. The rule provides the scale.
The Carson is much the smaller of the pair, and it weighs less, too, though at three ounces, the Alpen can hardly be said to be backbreaking. Both monoculars sport a rubbery "armor," which, while it probably contributes very little to their ability to sustain hard knocks, does make them easy to grip — and that's a good thing, since both rely on screw focusing. Each also comes with a nylon holster and a lanyard. And both were cheap. Neither cost more than a meal for two hungry paddlers at the local burger bar. But that's where the similarities end. The Alpen struggles to bring objects at 18 feet into focus, whereas the Carson Close‑Up lives up to its name, focusing down to 10 inches. (These are the manufacturers' figures, but our experience more or less bears them out.) As a result, the Carson is a "distance magnifier" as well as a monocular. There's also a difference in nominal power: the Alpen is 10x; the Carson only 7x. Advantage Alpen. Yet for most purposes this small disparity is unimportant.
The bottom line? Both Farwell and I are happy with our Carsons, though Farwell isn't retiring the Alpen. It's better for viewing distant objects than the little Carson, whose focusing gets decidedly fussy when the target is more than 30 feet or so away. Neither monocular could be described as top of the line, of course. But we have no complaints on that score. Sometimes good enough is … well … good enough. And their negligible cost is perhaps their signal virtue.
What about it? Does the idea of a pocket‑sized spyglass sound appealing? If so, you'll want to take …
A Closer Look at Monoculars
Their virtues are obvious: light weight, minuscule size (most will slip easily into a PFD or shirt pocket), and — if you don't insist on world‑class optics — negligible cost. I've already hinted at their many uses, but now let's examine these in a little more detail. Monoculars are good for …
- Spur‑of‑the‑moment bird‑ and wildlife watching.
- Practical, on‑water navigation: finding the heads of portage trails, locating campsites, and identifying navaids (i.e., lights, buoys, and the like).
- Scouting rapids (you can't always get close, after all).
- Discovering where your buddies have got to.
- Studying the largely invisible world at your feet — if your monocular has a close‑focus capability, that is.
- Reading signs — POSTED signs, trailhead notices, and so forth — at a distance.
- Spotting the sails of pirate vessels.
Of course, binoculars will do all of these things, and do most of them better. But there's no denying that when an osprey dives on a fish, a monocular in your PFD pocket is worth at least two pairs of binoculars buried in a dry box. And the low cost of many monoculars quiets the nagging apprehension that often afflicts boaters when they unlimber costly optics in a canoe or kayak. Yes, you can buy waterproof binoculars. And waterproof monoculars, too. But these are typically both heavier and costlier than their more vulnerable counterparts — and waterproofing won't stop a pair of binoculars from sinking to the bottom of the lake if it's dropped. Given the low cost of a replacement, I'm content to protect my inexpensive Carson monocular with a freezer bag. It offers the best balance of weatherproofing and convenience.
Have I sold you on the virtues of monoculars? Good. But maybe you could use a little help with your shopping, particularly when it comes to …
Making sense of all those numbers. Luckily, it's not rocket science. All monoculars (and all binoculars, too) are labeled with their power and the diameter of the objective lens (in millimeters). My Carson monocular is a 7 x 18, for example. That means it magnifies seven times, and the objective lens — that's the large, light‑gathering lens at the front end — is 18 mm in diameter. The greater the magnification, the bigger things look, and the larger the objective lens (everything else being equal), the brighter the image.
More is not necessarily better here, by the way. If the magnification is too high, you'll find it hard to keep your target in view as you bob up and down in the swell. As luck would have it, though, seven power represents a happy medium between magnification, on the one hand, and target acquisition and retention, on the other. And while a bright image is desirable, especially in a night glass — this is why watchstanders on large vessels are usually issued 7 x 50 binoculars — a bigger objective lens necessarily means a bigger monocular. That's not an advantage in an instrument whose primary virtues include small size and light weight.
Pay attention to field of view and eye relief, too. More is better here, and most manufacturers will list both numbers. My Carson boasts a field of view of 472 feet at 1000 yards, a striking improvement over the Alpen's 303 feet and a great help when you're trying to find a soaring hawk high in a cloudless sky. Unfortunately, neither monocular offers as much eye relief as eyeglass‑wearers would like: 18 mm or more is ideal, but both the Carson and the Alpen claim only 10. Still, this hasn't proven to be a crippling handicap, even for "four‑eyes" Farwell.
Don't neglect close‑focus distance, either, and this is one of those times when less is more. After all, there's a lot happening in the world around you that's just a little too far away to see clearly with the unaided eye: hummingbirds sip nectar from tiny flowers, butterflies perch on reed stalks, a wren scolds you from a nearby spruce… And as I've already noted, the Carson's incredible close‑focus distance (10 inches) is unmatched by any monocular or binocular I've ever come across. It's your passport for adventures in the near distance.
OK. You have your new monocular in hand. Now you'll want to know …
How to get the most out of it. This is common‑sense stuff. Binoculars are easier to hold steady in a seaway, but if you rest your forefinger against your brow when you bring the monocular to your eye, you'll find it possible to keep the wobble in check. Focusing can be clumsy, however. The Alpen can be focused with one finger — just — but the Carson really needs two hands. On the water, when it's hard to spare two hands for any chore other than paddling, I prefocus my Carson for middle‑distance targets. It works. After a fashion.
Target acquisition is another area where binoculars shine, and monoculars come up second best. Farwell, with only one good eye, still finds it easier to aim binoculars. But practice makes — if not perfect — at least good enough. And the molded lanyard loop on the Alpen can double as a peep sight. That helps. Which is a very good thing, given the Alpen's rather mingy field of view.
What did I tell you? This is just common sense, right? So all that remains is to …
Care for your new possession. Even cheap tools deserve a little TLC now and then, particularly if you depend on them. And once again, it comes down to common sense. Cleaning lenses is always fraught. So keep your fingers off them. Even eyelashes can leave greasy trails on an eyepiece. Be sure to protect your monocular from downpours, spume, and sand, too. Freezer bags work well for this. But when you can defer the chore of cleaning no longer — and that time will come, sooner or later — be sure to use a blower, a soft brush, and a clean microfiber cloth. Other than these obvious precautions, however, there really isn't much to say on the subject. Avoid becoming overprotective. Your monocular won't do you much good if it's buried deep in a dry bag or entombed in an ammo can every time you need it. It's a tool to be used, not a collector's item to be cosseted. Stay focused on that, and you won't go far wrong.