/A PHOTOGRAPH BY TODD MCLELLAN/
↓ THINCOMEG APARTS^
DISASSEMBLY REPORTNUMBER
OF PARTS:172
16 July/August 2019 _ PopularMechanics.comBinoculars
MODEL:
MAVEN BPRODUCED:
USATIME TO
DISASSEMBLE:
2 HOURS,
5 MINUTESHOW YOUR WORLD WORKS
NOTES:Whether you’re gazing up at the stars through a telescope or sighting a bird
with a trusty pair of binocs, whoever made your glass put a lot of thought into how
to gather light and hold tight to it. This is why telescopes, primarily used when
it’s dark out, have such big objective lenses. Inside a pair of binoculars—really,
a joined set of telescopes, allowing for the sense of depth that comes from two-
eyed vision—light passes through multiple lenses and prisms to be magnified,
oriented, and shaped. Every time light strikes a surface, some of it is lost.
According to Maven’s Brendon Weaver, the cheap binoculars you grew up with
might transmit 75 percent of the light that enters all the way to your eye. For these
binoculars, that number is upward of 90 percent. In fact, the v iew is so shar p that
particularly on field-flattening models, which have extra optical elements that
keep the view sharp even at the very edges of the lens, people can get motion sick
while panning around: The light is so perfectly refined it’s overwhelming for a
brain used to dealing with two measly human eyes.THE WOODS
You’re out with a friend, walking in
the woods, the rubber armor (11) on
the magnesium barrels (9) of your
binoculars tapping lightly against
your chest with each step. Then you
hear it: a repeated, scratchy, beggar-
ing call. Almost like a witch’s cackle.
Somewhere above you. You freeze,
take the lens caps (2, 13) off the
binoculars, and raise them to your
eyes. You scan the trees, and when
you find what you’re looking for, you
quietly hand the binoculars over to
your chum.THE ADJUSTMENTS
Unlike you, your friend doesn’t wear
glasses, so she twists the eyecups
(3) to their deepest depth. That way,
when the binoculars rest against her
face, the ocular lenses (4) are about
as far from her eyes as they were
from yours when the binoculars
were resting against your glasses.
Then she pivots the hinge (8) so
the barrels align with her eyes, and
twists the focus wheel (5) to clearup the image. She starts to sight the
binoculars where you were looking,
but something is still a little off, so
she makes an adjustment for the
difference between her eyes: First,
she covers the barrel with the diop-
ter ring (1) and brings one eye into
focus with the focus wheel. Then
she covers the second barrel and
uses the diopter to focus the other
eye—it adjusts lenses inside only
one barrel, so now the two barrels
are focused slightly differently,
to match the difference in acuity
between her eyes. Now when she
uses the focus wheel again—it’s con-
nected through a series of gears (7)
and pi ns (10) to the optical elements
in both barrels—both eyes w ill get a
sharp image. She retrains her sights
on the source of the sound.THE LIGHT
Light bounces off the trees and
enters the binoculars’ objective
lenses (12). (The objective and ocu-
lar lenses are actually sets of lenses,
with each element performing afunction like magnification, color
correction, or sharpening.) After the
objectives, the image of the trees is
magnified, but also inverted, so it
continues to the binoculars’ roof
prisms, named for the 90-degree
angle formed by two of their faces
(like a gable roof). In passing
through this pair’s Abbe-Koenig
prism assemblies (6), the image is
righted with a minimal number of
“bounces,” meaning minimal light
loss. (An Abbe-Koenig prism also
ejects light on the same a xis it came
in on, so the binoculars can have a
better form factor than older, wider
pairs that have the ocular lens offset
from the objective.) The light from
the trees then passes through the
ocular lens set, out the eyepieces,
and, finally, enters her eye, and she
gasps at what she sees: two pileated
woodpecker chicks sitting in a hol-
low in the tree, yawping at their
mom, who sounds a higher and
calmer chirp, more laugh than
cackle, and gives her babies some
food. —Kevin Dupzyk