Small is Beautiful
Getting Close to Nature with a Hand Lens
By Tamia Nelson
I drifted lazily in less than a foot of water, while a slanting
autumn sun illuminated the 'Flow around me. Riffles gently rocked my
kayak. I sat relaxed, feet off the blocks, paddle resting across my
cockpit combing. Through half-closed eyes, I watched the play of
sunlight on the wave-washed beach just a boat-length away.
Suddenly, I became aware of a constellation of twinkling points all
along the sandy shore. I picked up my paddle and moved in closer. When
my boat grounded, I reached down and scooped up a handful of sand. The
grains were all of a size, but they varied greatly in color. That was
all I could tell on quick inspection, but by now I was really curious.
So I pulled my hand lens out of the pocket in my life jacket where it
travels and looked through it at a smear of sand in my palm.
Seen under ten-power magnification, the individual grains leapt
into focus—each one distinct. As "alike as grains of sand"? What
nonsense! Each was unique. Some were well-rounded bits of quartz,
ranging from glassy transparency to dullish tan. Others were tiny,
black double pyramids of magnetite. As I rolled these in my hand, the
magnetite crystals sparkled in the sun.
Of course, a hand lens isn't usually thought of as paddling gear,
but for decades Farwell and I have taken one of these powerful little
magnifiers along on all our trips. They're a natural complement to our
binoculars. What "
far-seeing eyes" do for distant objects, hand lenses do for the
invisible world beneath our feet. They're wonderful tools, and they're
inexpensive, too. The best hand lens money can buy—a Bausch &
Lomb 10x Hastings triplet, for example—costs no more than the
cheapest pair of good-quality binoculars. Better yet, if you're happy
with less than the best, you can get a perfectly serviceable hand lens
for only ten bucks. Now that's cheap! They're handy, too. No bigger
than your key ring and weighing no more than the change you get from
buying a cup of coffee, a hand lens can find a place in even the most
ardent go-lighter's pack.
OK. Hand lenses are cheap and handy, but what do you look for when
you go shopping for one of your own? What are the hallmarks of a
high-quality hand lens, in other words? Simple. You want three things:
a good case, reasonable power, and good-quality optics.
What's a "good case"? Look at the sketch above. When not in use, a
hand lens pivots into an attached, protective post-and-plate case. If
the case fits snugly—if, that is, it's easy to pivot the lens in
and out, but if it then stays put—and if the case is made of some
sturdy, corrosion-resistant material (chromed brass or hard plastic,
for example), then you've got a good case.
"Reasonable power" is a bit harder to judge by inspection, but
you'll quickly learn what it means. Too little power (3x or less, say)
is, well, just too little. A hand lens is a magnifier. You want
it to magnify, don't you? Of course you do! Then again, as Mae West
probably didn't say, too much of a good thing can be awful. Too much
power means too small a field of view, as well as too short a working
distance. This last is particularly important. Sometimes you need to
keep your distance. Whether you're inspecting the stinger of a
not-quite-dead honey bee or looking at the wood chips in beaver
scat—both are fascinating things, by the way—you don't want
to get too close to your work. How much power is too much? It's a
judgment call. How far do you want to be from what you're looking at?
Anything more than 20x is a microscope, not a magnifier. It's
definitely too much. Ten power (10x) is a good compromise. It's high
enough to be useful, but low enough to let you stand back. I like it,
and so do many pros, including botanists, geologists, and graphic
artists.
And optical quality—what about optical quality? That's even
tougher to judge. Tougher, but not impossible. Like binoculars, the
best test of a hand lens is side-by-side comparison with several
others. Failing that, the next best thing is an extended, critical
trial. Here's what to look for. A good lens will have a crisp, bright
image. It won't distort colors or create rainbow halos around objects.
Finally, it will have a broad, flat field. Straight lines will look
straight. Distortion, even at the edges of the field where it's always
most noticeable, will be slight.
Can you tell a good lens from a bad one by reading catalog copy?
Maybe. The best lenses are probably those identified as Hastings
triplets, but not all Hasting triplets are equal. And some doublet
(two-element) lenses are pretty good. I have both types, and each is
perfectly satisfactory, though the triplet is noticeably better. In
evaluating a lens, look through the lens, not at the label. What
should you look at? Almost anything. Look at the print in your daily
newspaper, the surface of your skin, or—as I did shortly before I
sat down to write this piece—the minute bones of a fossil fish
embedded in a Green River siltstone. Look carefully. Look critically.
Then make your choice. You can believe your eyes.
And, now, speaking of choice.... Everybody likes to have a choice.
So why settle for a single power when you can have three or more? Some
manufacturers make two- and even three-lens magnifiers*, after all.
The idea is attractive. You can use the lenses singly or in
combination. The result? A whole smorgasbord of powers, and all for
half the price of a single Hastings triplet lens. You'll always be
able to match the exact power to each job. This sounds pretty good,
doesn't it? But is it? In a word: No. I suppose there may be an
exception somewhere, but every two- and three-lens magnifier I've
tried to date has been a disappointment. Color fringing. Distortion.
Blurry images. Not quite ready for prime time, in short. If you really
need (or want) magnifiers of two different powers, I'm afraid you'll
have to buy two single-power hand lenses.
Now, supposing I've sold you on the idea of taking a hand lens with
you on your next paddling trip, where can you buy one? You may get
lucky. You may find a good-quality lens in a local outfitter or hobby
shop. But you most likely won't. That's not a problem. You'll find all
the selection you could want in the catalogs of scientific and
forestry supply houses like Edmund Scientific and the Ben Meadows
Company. Study the catalogs, and then order the lens that looks right
for you. Just be sure that you can return it if it proves
unsatisfactory. Even simple optical instruments are complex things.
Sometimes the best manufacturers miss a defective lens element or a
poorly-aligned case.
Once you're satisfied with the lens you've purchased, it's time to
go exploring. And, if there are any children in your life, why not
invite them along? In fact, if they're old enough to trust with small
objects, consider getting them inexpensive, good-quality hand lenses
of their own. (Attach brightly colored lanyards to the cases, however,
so that a "lost" lens can be found easily and returned to its owner.)
Kids love magnifiers. There are few better ways to encourage their
natural curiosity.
With magnifier in hand, the wilderness begins at your own skin.
Everywhere you turn, you'll see familiar things in a new light. Start
by holding your lens close (1"-2") to your eye, and then bring both
eye and lens down to your subject. Compare different fabrics,
different woods, even different papers. Look at the leaves and stems
of your houseplants. Have you found a book louse in your library? Give
it a stay of execution while you examine it from head to abdomen. Can
you see the rust-red spots? When you're done, consider leaving it as
bait to attract a spider-like pseudoscorpion—another subject for
your lens, and an even more interesting one!
Out-of-doors and on the water, you'll find that the immense,
microscopic wilderness you've been exploring suddenly gets even
bigger. Check out the sand grains on the beach, as I did. In spring
and early summer, look for black fly larvae in small streams. If you
find them attached to a flat rock near the surface, you can watch
their delicate cephalic fans strain food from the rushing water.
Search the stream bottom for the improbable sand-and-stick tubes that
caddisfly larvae call home.
Ashore, at any time from late spring through autumn, examine the
caps, gills, and stalks of forest
mushrooms. See if you can identify the incisor marks left by
hungry mice and voles. (But DON'T assume that you can eat what they
can! That could be your last mistake.) And in winter, when ice has
silenced all the streams and you'd think that insects of any sort
would be long gone, keep your eyes open for tiny, primitive
springtails ("snow fleas"), swarming like a sooty smudge on the
surface of the drifting snow. The long, forked "spring tail" is worth
a look, but you'd better be quick. These lively creatures don't hold
still for long, and they can leap a foot or more with each bound.
That's it. You've got the idea by now. To someone with a hand lens,
there's a wildlife park in each square foot of stream bottom, and a
wilderness in every brush pile. Be sure to use a notebook to record
your discoveries, though—and remember, "Small is beautiful!"
* Don't confuse a three-lens magnifier with a triplet.
A triplet is a single lens with three elements. A three-lens
magnifier, on the other hand, has three individual pivoting lenses.
Copyright © 2000 by Verloren Hoop Productions. All rights reserved.