What To Know When Buying Binoculars
Author: Chuck Fitzgerald
We are asked nearly every day: "What are your best binoculars?"
And every day we answer: "How do you plan on using them?" We are
not trying to be evasive with our answer, but the truth of the
matter is – the best binoculars for one purpose may be the worse
binoculars for another. We want you to Get It Right The First
Time.
Understanding your application is paramount in determining
the best fit – for you.
Although there are many other specifications and qualities
which determine the usefulness of binoculars, we will discuss in this article
the primary characteristics for determining the best fit for your application.
But before we show you the list, we should go over some basic terminology. What
do the numbers on binoculars mean?
All sporting optics (binoculars, spotting scopes, night
vision goggles, etc.) use the same nomenclature to describe important features.
As an example, a pair of binoculars may have 10x42mm listed as a technical
specification. But what does this mean?
The "10" refers to the magnification power of the binoculars
– that is – objects viewed will appear to be 10 times closer than when they are
viewed by the naked eye. The second number in our example is "42mm." This refers
to the diameter, in millimeters, of the objective lenses on the binoculars. The
objective lenses are located on the end of the binoculars furthest away from
your eye when viewing. As with the aperture of a camera lens, the size of
objective lens determines the amount of light that can enter your binoculars.
If your binoculars are going to be used during low light
(hunting and astronomy are good examples) you had better have large objective
lenses.
Another important number describing binoculars is called
field-of-view. A field-of-view of 390' indicates that the width of the sight
picture is 390 feet at a distance of 1000 yards. Field-of-view is determined by
magnification and the focal lengths of the objective and eyepiece lenses. More
magnification always means less field-of-view.
This specification is sometimes expressed in degrees. A
field-of-view of 6.5 degrees equates to 341' (6.5 times 52.5 equals 341). How
well your binoculars will serve you in low light conditions is described as
Twilight Performance. Although many things, such as overall design and quality
of glass impact this specification, magnification and objective lens diameter
are the chief components.
A quick way to determine the Twilight Performance of
binoculars is to multiply the magnification power (first number) times the
objective lens diameter (second number). The higher the result, the better the
Twilight Performance. As an example, 10x42mm binoculars will have better
Twilight Performance than 8x50mm binoculars (420 versus 400).
Now that we understand some basic terminology, here is “What to
Know When Buying Binoculars."
* While compact binoculars weigh as little as a pound, by
using them you will undoubtedly sacrifice performance. If performance is your
main consideration, full sized binoculars are preferred. Anything weighing over
about 1.5 pounds will get heavy fairly fast. Use a binocular support system to
evenly distribute the weight across your shoulders instead of using a strap
around your neck.
* The amount of light available while using your binoculars
will determine –more than any other consideration – which binoculars are best
for you. Low light uses such as hunting, birding and astronomy require larger
objective lenses.
* The distance you will be from the object you view will
determine the magnification power required in a pair of binoculars. If your
application is bird watching, theater or sporting events, a low powered
binocular will suffice in most cases. But if you're into astronomy, you'll need
a high powered pair.
* The minimum focal point in binocular terminology refers to
how near an object can be to you and be still be viewed in focus. This tends to
be important for birding but not so important for most other uses.
* Binoculars with a magnification power greater than 10x (and
without a stability feature) will be difficult to hold steady. This becomes
important when viewing the night sky or distant mountains. A tripod may be a
good thing to have if you’re using binoculars with high magnification.
* Using your binoculars outdoors will usually subject them to
moisture. Waterproof binoculars are preferred for all marine, hunting, birding
and other nature related activities.
* The greater the magnification, the narrower the
field-of-view. If field-of-view is important to you, don't purchase the most
powerful binoculars you can find. This becomes very important when viewing
objects that move quickly such as antelope, race horses, shooting stars or race
cars.
* As with almost everything else in life, with binoculars you
get what you pay for. There are binoculars that cost under $10 and others which
cost in excess of $2,500. My experience says you will need to spend at least
$250 for a pair of binoculars worth having.
* There is no such thing as “one-size-fits-all” when it comes
to sporting optics. If you have multiple uses for binoculars, you will most
likely end up with multiple pairs of them – and that’s O.K.
Your understanding of these few simple tips will not only help
you in acquiring the correct binoculars for your application,
but they will also help you with successful viewing – no matter
what you’re looking at. Use this information and you’ll Get It
Right The First Time. Get Outdoors!
About the author:
Chuck Fitzgerald is Owner and President of Phoenix, Arizona
based BackCountry Toys, an online store providing backcountry
specialty gear and educational information to outdoor
enthusiasts. Visit www.BackCountryToys.com to receive the free
newsletter "FreshAir” or call (800) 316-9055.
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