a 6.5˚ field-of-view appearsto have a
65˚ range; qualifying itas a wide angle
instrument. The greater the apparent
angle-of-view, the easier itis for you to
pinpointand track your subject. The
Canon binocular line offersmodels with
apparentangles-of-view that range from
45˚ to 67˚.
Differences in brightness
The brightnessof an image is associated
with the amountof incidental light that
isreflected bythe lens. Uncoated lenses
can reflectaway as much as 8% of
incoming lightper lens element —
resulting in a dim image. For thisreason
Canon employsSuper Spectra Multi
Coating to enhance brightness.
Since manythings contribute to the
brightnessof an image, be sure to
consider the following factorsasyou
compare binoculars:
Exitpupil diameter
The size ofthe image that emerges at
the binocular’seyepiece impacts image
brightness. In dimlylit settings, a large
exitpupil, for example 4.2mm found on
the 10x42LIS WP, deliversbrighter
results. For daytime viewing, binoculars
with exitpupil sizes between 2.5 and
3mm are often sufficient.
Objective elementdiameter
Thisrefers to the front lens element
measured in mm. Allthings being equal,
the larger the lensin front of the
binocular, the more lightit can take in
and the brighter the viewing image will
be. The 18x50 ISAW and 15x50 IS AW
have the largestobjective lenses in
Canon’sbinocular lineup.
Twilightcoefficient
One difficultywith using traditional
numericalratings to determine a
binocular’ssuitability for low-light
viewing isthat higher magnification
binoculars, even those with smaller exit
pupilsize or “relative brightness” ratings,
can often revealbetter detail in low light
because oftheir higher magnification.
TwilightCoefficient or Twilight Factor
accountsfor the magnifying power of a
pair ofbinoculars, and can be a useful
rating—especiallyif viewing at dawn or
dusk, or deep shade viewing conditions.
Judging quality
When evaluating binocularsbrands and
models, here are few thingsto look for:
Alignment
Ifthe parallel tubes of the binocular are
outof alignment due to a manufacturing
defector accident, you’ll see two similar
butseparate images. There is no way to
repair thisproblem and it renders the
binocular virtuallyuseless.
Color
Focusthe binocular on a white object.
Checktwo things: first, that the white
objectappears a faithful white tone
Canon’sSuper Spectra Multi Coating
Narrowfield- of-view
a. Real field-of-view: 6.5˚b. Apparent
angle-of-view: 65˚
c. Field-of-view at
1,000 yards: 340.6 feet
Looking through a 10x42L ISWP binoculars
ata subject 1,000 yardsaway
Wide field- of-view
13
Find the binoculars that fit your needs.Waterproof and all weather
Severalmodels in the Canon binocular
line are waterproofor water-resistant.
Designed to be used outdoorsand on the
water, these modelsare built to withstand
a broad range ofconditions including
rain, humidityand more. The new Canon
10x42LIS WP offers Canon’s highest
standard ofwaterproof performance—it
can be completelysubmerged.
Lead-free optics
Canon usesenvironmentally friendly
lead-free glassin its optical systems.
Thiscreates the high-quality
performance you demand from your
binocular while protecting the
environmentfrom unnecessary harm.
The importance of objective
lens diameter
Binocularsare described by the power
oftheir magnification (18x, 15x, 12x,
etc.) combined with the diameter oftheir
objective lenses(50mm, 42mm, 36mm,
etc.) The greater the magnification power,
the larger your viewing subjectwill appear
in the objective lensas you look through
the binoculars.
For instance, ifyou use the 10x42L IS WP
to tracka subject 100 yards away, it
appearsto be the same size as a subject
located just10 yards away seen without
binoculars. Allthings being equal, the
larger the diameter ofthe objective lens,
the more lightit can admit for brighter,
more detailed images. So binocularslike
the 10x42LIS WP, 18x50 ISAW and
15x50 ISAW produce particularly bright,
clear images.
The key to Field-of-View
The field-of-view isthe area you see when
you lookthrough the binocular. The higher
the magnification power, the narrower the
field-of-view. The apparentangle-of-view
isthe product of the magnification times
the realfield-of-view. So in the case of the
10x42LIS WP, the 10xmagnification with
100 yardsaway
with the naked
eye.
10 yardsaway with
the naked eye. With a 10xmagnification binocular,
the hotair balloon 100 yardsaway
will seem asif it were 10 yardsaway.
When bright....
When dark....
Viewer’spupil
diameteris 3.0mm.
Pupil dilates
aswide as 7.0mm.