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[at-l] Here's the cut and pasted text from the site...Binoculars
- Subject: [at-l] Here's the cut and pasted text from the site...Binoculars
- From: Trailmixup@aol.com
- Date: Wed, 28 Jun 2000 22:10:36 EDT
Binocular Buying Guide
What the numbers mean
Numbers are used to indicate binocular specifications, for example 7x42. The
first number is the magnification. This number tells you how many times
larger or nearer an object will appear when viewed through the binocular.
Seven times larger than with the naked eye in our example. The second number
indicates the diameter of the objective lenses in millimeters. The objective
lenses are the large lenses at the front of the binocular. The larger the
objective lens diameter the more light it can transmit back to the eye.
Higher numbers don't necessarily mean better binoculars. Magnification and
light gathering power should be determined by your application. Not by the
"Bigger is Better" rule.
Field of View
The width of the area seen through the binoculars at a specified distance is
the field of view. It is usually expressed in meters at 1,000 meters.
Generally the lower the magnification the wider the field of view. Binoculars
with a wide field of view make it easier to scan large areas or follow a
moving object.
Exit Pupil
The exit pupil is the bright circle of light that appears in the rear
(ocular) lens when the binocular is held away from the eye. The diameter of
the exit pupil in millimeters is equal to the front (objective) lens diameter
divided by the magnification. 6mm in our example above. All other things
being equal, the higher the number he brighter the binocular.
Eye Relief
The eye relief determines how far your eye can be from the eyepiece while
still allowing a full field of view through the binocular. This is important
to eyeglass wearers. Look for a High Eye Relief design if you plan to wear
glasses while using your binoculars.
Design Types
There are two basic design types of binoculars: Porro Prism and Roof Prism.
Porro prism binoculars are the conventional type with large lenses in the
front and small lenses in the back. The front and rear lenses are offset.
Roof prism binoculars are designed with both sets of lenses aligned in the
same tube, like two telescopes side by side.Porro prism binoculars are
generally brighter and less expensive. Roof prism designs are more costly but
usually less susceptible to damage from rough handling.
Focusing
Center and Individual are the two focusing systems commonly found in
binoculars. Center focus binoculars are equipped with a center mounted wheel
that simuntaneously focuses both tubes. Individual focus binoculars have
individual adjustment rings on each eyepiece. This allows separate focusing
of each tube. This system is popular in Military and Marine binoculars.
Quality center focus binoculars provide some type of diopter adjustment to
compensate for the small difference between the viewers right and left eyes.
Minimum Focus Distance is also a consideration in binocular selection. A
close focusing binocular allows you to view objects closer in in sharp
detail.
Armoring
Armored binoculars are covered with a rubber or polyurethane material that
makes them more resistant to impact damage and scratches. The armoring helps
eliminate disturbing noise caused by contact with metal objects. Most armored
models are easier to grip and provide better resistance to the elements.
Check the specifications if water proofing/resistance is important. Water
resistant models are not damaged by humidity or light rain. Water proof
binoculars can actually be submerged without damage.
Compact Binoculars
Compact models are smaller and lighter than conventional binoculars. A
lightweight roof prism design allows some 8x and 10x models to be easily
carried in a pocket. This is a considerable advantage for hikers, sports
enthusiasts, or anyone desiring good performance in a small package.
Selecting the Right Binocular
Choosing the right binoculars for you is not a difficult task. Some factors
to consider are magnification, brightness, size/weight, exposure to the
elements, and price. First decide what your primary use will be. If you are
viewing at long distances or want to see greater detail you may want to
select a binocular with a 10x or greater magnification. For moderate
distances a 7x or 8x may be more useful. A higher magnification binocular is
usually larger and heavier and sometimes less bright. Lower magnification
models tend to have a wider field of view and make it easier to keep an
object in view while in motion, on a rocking boat for example. Look for a
large objective lens if you work in low light, as in viewing at dawn or dusk.
Larger binoculars are generally easier to hold steady and offer a brighter
image than compact binoculars. They are however, less convenient and heavier.
Your primary use will determine the best balance of these factors. You may
find that your needs are so diverse you need more than one pair. Remember
when considering price, you are investing in a quality optical instrument
that will give you many years of viewing pleasure.
<A
HREF="http://www.binoware.com/cgi-bin/perlshop.cgi?ACTION=ENTER_SHOP&THISPAGE=
buyers.html&ORDER_ID=!ORDERID!">Click here: The Binocular Warehouse : Quality
binoculars at discount prices</A>
Trailmixup
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