Many customers use their binoculars to extend
their personal security zone, because they allow
for viewing possible danger before it is close
up. But, of course binoculars are also just
for fun or sport! To help you choose the best
binoculars for your purpose, we start out with
general recommendations. Then, we go into more
details as you read. So, if you don't want to
delve into the details of optics and confusing
specifics, you can stop reading at any time.
Opticians have a technical
way of saying the above. Their terminology is...
It depends on what you want to view...
Binoculars to keep in the car:
In your vehicle, you probably would rather have
a compact set of binoculars that you can fit into
the console, door bin or glove box. Again, consider
the distance you will want to view at. In my experience,
I like to look at things far off like mountain
tops, across a lake, boats on the lake or an airplane.
That distance is so far off it's considered infinity.
But, I might also want to see up on a building
or bridge top, which is closer but still could
be 500-1,000 yards, so again - infinity as far
as binoculars are concerned. So, look for COMPACTS
with as long a range as you think you might use.
For long distance you want high magnification,
and that is the first number on the left side
of the "X" in binocular specs. 8X
may be OK but 10X
will give even more clarity at distance. But,
if you're looking closer up, any general purpose
compact binoculars may suit you and 8X would be
fine for you.
How to remember this: For seeing far away, get
a high number before the X: 10X40
is better than 8X40
in this case.
Birding and wildlife: 8x40,
8x42 or if you have a steady hold, can tolerate
wobble or have a tripod 10x40, 10x42 and roof
prism. (You can read more about roof prism binoculars
below.) Again, if it's damp or rainy where you
go birding, look for fogproof and perhaps even
Star gazing and astronomy without a tripod:
If you want to go without a tripod, binoculars
are really only good for looking at sections of
the sky, such as a star field or a constellation.
(If you want to view a planet, you will need a
tripod and a scope so skip to the next paragraph)
.So, you actually don't need a lot of magnification
and 7X, 8X or whatever will do. Don't go higher
than 10X or the picture will become very wobbly
because your muscle movements will make the view
With tripod, you can go for the higher magnifications
like 12X through 16X. A zoom like 10-22X50 would
As far as lens size goes, get X50 or higher.
The higher the better. But, remember you have
to carry your binoculars and X60 is heavier than
Out on the boat: For marine
binoculars, you most definitely want waterproofing
Here you're worried about the wobble thing, because
the boat bobs around in the water and even with
a tripod you will see wobble in the images. This
is why 7X50 or some other 7X binocular is usually
recommended. A 7x50 with a big exit pupil of 7
or more has always been the most recommended marine
binocular. (Find out more about exit pupil measurements
View my kids in the soccer game or out
in the yard: 8x40, 8x42 is probably fine.
You don't care if you enlarge every hair on their
head. You just need a boost in enlargement so
you can view your kids or the players out there
in general. But, you do want to see a wide Field
of View, no doubt. More about FOV later on.
The 8X part of the the mearurement,you will remember,
tells you enlargement or magnification and will
make things 8 times bigger. Additionally, if the
lighting is good, you don't need the bigger lenses
so even X21 and up are on the small size but will
probably work fine. If you are watching play by
play and really into the kids competitive sports,
and will be looking for longer than a few glances,
you can go for bigger lenses such as the X42.
Stadium sports: 8x40, 8x42.
Same as above. Zoom might be nice though, if you
want to zoom in on someone in the stands, so something
or 8-10x42 would be useful in this case. Remember
the zoom spec is the range of numbers on the left
side of the X.
Hiking: compacts such as an
8x25, 10x25. You don't get a very big lens with
compacts, but they are not a lot of weight to
carry around either. So, that's your trade off
when choosing binoculars for hiking.
Surveillance and Home Security: Check out binoculars
that have a lens on the larger size, which is
or larger in their rating. Here's why...
Many of our customers say they want to be able
to check out what's going on out in the street
in front of their homes. For example, the last
time I used my binoculars it was to look outside
from my bedroom window and find out what was going
on inside a car that was parked out in the street
in front of my house at 2 a.m. The street is about
50 yards from my bedroom window. How far is the
street from your window? 25 or 50 yards?
Also, for surveillance consider your typical
lighting conditions. I usually only want to check
things out with binoculars when it's dark or dusk
out. In this case, I need a large lens that will
capture more light. Also, I might want Night Vision
Since X40 and higher designates a larger lens
size, that's what to get in this case.
For surveillance around your property, buy binoculars
that end in X40
or larger. That's on the large end of lens sizes/diameters
for binoculars. For example, 8X40
or some other high number like X50
. If you can get the higher number, the better.
binoculars would be nice but
it's not required in this case.
How to remember this: For surveillance and low
light, get a high number after the X because that
is the lens size. 8X50
is better than 8X40
in this case.
Hunting: 8x40, 8x42 or if you
have a steady hold, can tolperate wobble or have
a tripod 10x40, 10x42 and roof prism. (You can
read more about roof prism binoculars below.)
Is it damp out on the trails? Does it rain? If
you're not in the desert, you want your binoculars
to be waterproof or at least fogproof.
How to remember this: When hunting, if you are
looking for game or varmints far off like 500-1,000
yards out there, get a high number before the
X: 10X40 is better than 8X4. But, if you are in
the woods or looking across a field, just to see
what's up (and your rifle scope will do the rest)
you can use a lower magnification, so 8X may do
it for your.
Also, go light, because you have to carry everything!
That means you may want a big lens but don't want
to carry a humongous set of binoculars. So, get
around X20 to X40 for daytime.
But, if you're hunting at dusk, you will need
up around X50 or greater and will have to deal
with the added size and weight.
With tripod, you can go for the higher magnifications
like 12X through 16X. A zoom like 10-22X50 would
Want more details? You've come to the
do binocular specs work?
typical binocular is labeled with two numbers,
for example 8x40, or 7x35
etc. A few binoculars use three numbers as in
10-22x50. These are zoom
does the first number in a binocular mean, such
as the 8 in 8x40?
first number - the 8 - is the magnification. That's
how many times the image is enlarged over normal
when you look through the binocular. 8 means the
image will look 8 times larger or 8 times closer
than it really is. An 8x50, 8x40, 8x20 all have
a magnification of 8.
What about something like 8-24X25?
Since the number on the left is the magnification,
the binoculars go from 8 to 10. These are zoom
binoculars.You can change the magnification
from 8x up to 24x.
Here are some interesting things about magnification.
As the magnification goes up, the image brightness
goes down, field of view (the amount of territory
seen through the binocular) goes down and, just
as importantly, image steadiness also goes down.
More about all these other specs later. However,
it's important to know that bigger numbers are
not always better due to the trade offs inherent
in optics. For example, take wobbliness, which
occurs when the spec is 10X or higher. The image
wobbles because a binocular magnifies not only
the image, but also your muscle movements and
you might even see the image jump each time
your heart beats. That is why, most people find
that a 10X binocular is about as high as they
can go without a support or tripod.
does the second number in a binocular mean, such
as the 40 in 8x40?
second number tells how big the lens is. It measures
the diameter (width) of each front lens in millimeters.
This number directly affects brightness and sharpness.
An 8x40, then, will produce a brighter
and sharper image than an 8x25, even though both
enlarge the image an identical eight times. The
larger front lenses in the 8x40 also let
in wider beams of light as it enters the eyepieces
(see exit pupil below for more on this
topic). This makes it more comfortable to view
with an 8x40 than an 8x25.
On the other hand, the larger front lenses
in the 8x40 binocular
also make the 8x40 bigger and heavier than the
8x25 binocular. An 8x25 may not
be optically as good as an 8x40,
but its smaller size can make it easier to carry
or store. You may want to make sure your binoculars
are not too heavy or big. Or, size may not be
a consideration you are worried about.
The technical term for this number is the Objective.
Why call it that? Because it refers to the front
lens and, that is the lens that forms the image
of the object. So, it's about the object
about Field of View?
of View (FOV) is the amount of territory you see
when you look through the binocular. Imagine a
fence 1000 yards away. If a binocular has a Field
of View of 372 feet at 1000 yards, you will see
372 feet of the fence. If the Field of View is
250 feet at 1000 yards, you will 250 feet of fence.
Field of View depends on magnification and
also the binocular's eyepiece. Generally, when
you get more magnification, you will get less
Field of View. This means that 10x will show
more details on the fence at 1000 yards than
8x will show, but 10x will not show you as wide
a section of fence.
What about eyepiece design and Field of View?
Wide-angle eyepieces will increase Field of
View, if they are of good optical quality. However,
they are pricey and can also cause the image
to be less sharp.
In short, Field of View isn't one of the binocular
specification numbers as in 8X42. But, you can
get more Field of View if you get a bigger magnification
or a wide angle eyepiece.
- Exit Pupil in a binocular
is how big a beam of light comes in through the
eyepieces. This is measured in millimeters. You
can see the exit pupil by holding the binocular
out at arms length, so that you can see a circle
of light in each eyepiece.
If you want to calculate the size of the exit
pupil, divide the first binocular number into
the second binocular number. A 10x50, 7x35,
and 8x40 all have an exit pupil equal to 5 millimeters.
Exit pupil generally tells you what the image
brightness will be. Binoculars with larger exit
pupils give brighter images in dimmer light.
For normal daylight viewing, an exit pupil of
2.5 or 3 is fine. For low light surveillance,
stargazing and astronomy, an exit pupil of 5-7mm
The biggest exit pupil that your eye can handle
is actually 7. So, your eye can't really use
anything larger, but keep reading for other
interesting aspects of what your eye can do
with a bigger exit pupil.
Also, the exit pupil measurement doesn't take
into account the effects of lens coatings and
optical quality, so it doesn't give you the
whole story regarding how good an image you
can see with a particular set of binoculars.
But, consider this! A larger exit pupil is
easier to keep centered in your eye, so this
ishelpful when it is difficult to hold a binocular
steady, as on the deck of a moving boat! That's
why a 7x50 with an exit pupil of 7+ has always
been the typical recommended marine binocular.
- Relative brightness (RE)
is another general guide to image brightness,
because it is really just the exit pupil squared.
This means that binoculars with an exit pupil
of 5mm will have an RE of 25. It's just another
way of measuring the exit pupil.
about Twilight Factor?
you are going to be using your binoculars a lot
at dusk or in low light, such as dark cloudy days,
the Twilight Factor will tell you how much detail
you will mostl likely be able to see. It's the
square root of magnification times the objective.
Therefore, a 10x40 has a Twilight Factor of 20.
Remember that these measurements: exit pupil,
relative brightness and twilight factor
are really rough measurements and they do not
tell you about quality that can be due to special
lens coatings, type of glass and other manufacturing
techniquest that make a premium grade binocular
superior to lower grade models.
binocular specs include prism. What is
a prism, a binocular would produce an upside down
image. Binoculars have either porro prism or roof
Porro prism is one of the
most efficient, least expensive and earliest
types of of prism developed for optical
instruments. However, a porro prism is larger
and bulkier prism than a roof prism, which was
developed later on. Because of the weight, the
body of a porro prism binocular will also tend
to be more bulky.
You can always recognize a porro prism binocular
by its shape. In this case the eyepiece and
the front lens are always offset and are never
in a straight line. Optically, however, a porro
prism is very efficient.
Since is less expensive to make a porro prism
than a good roof prism, a good quality porro
prism binocular is every bit as good optically
as a quality roof prism at a much lower cost.
If you want to get the most optics for your
dollar, especially in a binocular under $200,
a porro prism is your best option.
Roof prism is smaller and it's shaped
like a little hut or roof. Its main advantage
of is its size and shape. Since roof prism is
smaller and more compact than porro prism, it
can be installed in a much more compact housing.
This makes the binocular easier to handle for
You can tell a roof prism binocular by its
shape. The eyepiece and the front lens are always
in a straight line or straight tube.
Roof prisms are more expensive to make to the
same optical standards as good porro prisms.
Another interesting factoid: Not all roof prisms
are made the same or of the same quality. Some
are phase corrected and these are the sharpest.
Others may have silver coated mirrors, and these
are brightest. And, some are aligned better
A good roof prism binocular is actually more
rugged and smoother to focus than an average
porro prism binocular, because the roof prism
is contained in its own cage and its focus mechanism
is usually inside the binocular instead of on
about optical glass grades like Bak4 or
quality binoculars use Bak4. Only inexpensive
binoculars use the lower quality BK7 grade
- Lens coatings are chemical coatings
on the lenses in a binocular to make images brighter.
Whenever light goes through a lens, a little bit
of light is lost. Some light gets reflected and
some of it gets absorbed by the lens. To minimize
loss due to reflected light, special lens coatings
are applied. There are three types of lens coatings:
(1) Fully Coated Lenses, (2) Multi-Coated Lenses,
and (3) Fully Multi-Coated Lenses.
Fully Coated lenses coated were the
earliest lens coatings and these are now the
least efficient. The coating is a single layer
of magnesium fluoride, and it is found only
on inexpensive binoculars. These lenses will
not produce images as bright as multi-coated
Multi-coated lenses in handheld
binoculars have severak layers of special chemicals.
The multi-layered coating allows the maximum
amount of light to pass through the lens. A
multi-coated binocular may have some lenses
coated and others not, but it will always be
brighter than a "fully coated" binocular.
A Fully Multi-coated binocular
produces the brightest image of an ycoating
system. All quality binoculars are fully multi-coated.
- Center Focus Binoculars use
a single wheel to focus on objects. It can focus
on objects both very close and far away, making
it the most versatile and commonly used focusing
system in a binocular.
- Iindividual Eyepiece Focus (IF)
Binoculars require you to focus each eyepiece
when looking at an object, but once focused for
your eyes, objects from 40 yards away to infinity
are always in focus and require no additional
focusing. This is a great system for medium range
and long range objects, but it is not well suited
for close in work. IF binoculars are most
commonly found in marine binoculars and
- Focus Free is an economy
version of an IE focus binocular, but the eyepieces
are locked and set at the factory and cannot be
adjusted. This means that you can never focus
on objects closer than forty yards away and it
also means that the binocular cannot be adjusted
for differences in strength between your right
eye and left eye. This is a serious shortcoming
for most people, since most have one eye a bit
stronger than the other.
- The diopter adjustment on
a binocular allows you to compensate for differences
in strength between you right and left eye. Since
most people have one eye stronger than the other,
this is a feature found on all binoculars
except for "focus free" models.
is the diopter adjustment on a binocular located?
diopter adjustment has been traditionally
located on the right eyepiece, but many models
today use a separate wheel or a locking mechanism
on the center focus knob.
- Interpupillary Distance is
the distance between the pupil of the eyes. All
binoculars can be opened wider or closed
tighter to accommodate different widths, though
people with very small faces or people with very
large faces may still have trouble finding a binocular
that will fit them.
- Minimum Focus or Close
Focus is the nearest distance at which a binocular
will focus on an object. A binocular will not
focus on an object that is any closer. This feature
is important for some uses, such as birding.
- Eye Relief is the maximum
distance your eye can be from the eyepiece and
still see the entire field of view. If your eye
is farther back than this distance, you will see
a reduced field of view. This is a concern if
you wear eyeblasses when looking through a binocular,
because eyeglasses alwyas prevent your eyes from
getting right up close to the eyepieces.
The minimum recommended Eye Relief is generally
14 or 15mm. However, if you have eyeglasses with
thick glass lenses, you should get 17-20 mm.
the eyecups on a binocular be in the "up"
position or "down" position when using eyeglasses
with a binocular?
the eyecups in the "down" position when
wearing eyeglasses and in the "up" position when
not wearing eyeglasses. (Older style binoculars
have rubber fold down eyecups, but most modern
binoculars "twist up" or "pull up" style eyecups.)
much weight in a binocular is too much to carry
aournd the neck?
over 35 ounces is too much to comfortably carry
around the neck. A weight less than 30 ounces
is much better. If your current binocular seems
too heavy to carry comfortably, you might want
to get a binocular harness that is designed to
support the weight on your shoulders instead of
- A fogproof binocular is one that
is guaranteed by the manufacturer not to fog up
due to moisture inside the binocular (any binocular
can fog up on the outside). A binocular is made
fogproof by filling it with nitrogen. Other labels
such as water-resistant, climate-proof, rain-proof
are not a guarantee of waterproofing.
- If you are using a binocular around
water or will be using it under harsh conditions,
waterproofing is a must. Even for more casual
use, though, a waterproof binocular is a better
sealed binocular and less likely to develop problems
with dirt and dust entering the binocular.
- An armored binocular is a binocular
with a body that is covered by rubber or another
synthetic material. Armoring protects it from
scratches, makes it more comfortable to hold and
also "quiets" the binocular when it accidentally
rattles against something (so you don't scare
the animals away). Armoring does not make a binocular
- You can mount a binocular to a tripod
if it is listed as tripod adaptable or
if it is threaded for a tripod adapter. If it
is listed as tripod adaptable, you may
still need to purchase a tripod adapter, though
a few large binoculars may have this accessory
Where is the tripod socket located on a tripod
is usually located at the front of the center
hinge where the binoculars fold. It is often hidden
under a cap.
When should I attach a binocular to a tripod?
time you have a binocular magnification over 10x
or 12x, you should attach a binocular to a tripod
to steady the image. Also, heavy binoculars with
a last number of 70 mm or more usually need a
tripod to support the weight.