1. Binoculars, field glasses or binocular telescopes are a pair of identical or mirror-symmetrical
telescopes mounted side-by-side and aligned to point accurately in the same direction,
allowing the viewer to use both eyes (binocular vision) when viewing distant objects. Most
are sized to be held using both hands, although sizes vary widely from opera glasses to large
pedestal mounted military models. Many different abbreviations are used for binoculars,
including glasses, nocks, oculars', binos and bins.
Unlike a (monocular) telescope, binoculars give users a three-dimensional image: for nearer
objects the two views, presented to each of the viewer's eyes from slightly different
viewpoints, produce a merged view with an impression of depth.
Binoculars to be used to view objects that are not at a fixed distance must have a focusing
arrangement which changes the distance between ocular and objective lenses. Traditionally,
two different arrangements have been used to provide focus. Binoculars with "independent
focus" require the two telescopes to be focused independently by adjusting each eyepiece.
Binoculars designed for heavy field use, such as military applications, traditionally have used
independent focusing. Because general users find it more convenient to focus both tubes
with one adjustment action, a second type of binoculars incorporates "central focusing",
which involves rotation of a central focusing wheel to adjust both tubes together. In
addition, one of the two eyepieces can be further adjusted to compensate for differences
between the viewer's eyes (usually by rotating the eyepiece in its mount). Because the focal
change effected by the adjustable eyepiece can be measured in the customary unit of
refractive power, the diopter, the adjustable eyepiece itself is often called a "diopter". Once
this adjustment has been made for a given viewer, the binoculars can be refocused on an
object at a different distance by using the focusing wheel to move both tubes together
without eyepiece readjustment. Most modern binoculars are also adjustable via a hinged
construction that enables the distance between the two telescope halves to be adjusted to
accommodate viewers with different eye separation. Most are optimized for the
interpupillary distance (typically 56mm) for adults.
There are "focus-free" or "fixed-focus" binoculars that have no focusing mechanism. They
are designed to have a fixed depth of field from a relatively close distance to infinity, having
a large hyper focal distance. These are considered to be compromise designs, suited for
convenience, but not well suited for work that falls outside their designed range.
Some binoculars have adjustable magnification, zoom binoculars, intended to give the user
the flexibility of having a single pair of binoculars with a wide range of magnifications,
usually by moving a "zoom" lever. This is accomplished by a complex series of adjusting
lenses similar to a zoom camera lens. These designs are noted to be a compromise and even
a gimmick since they add bulk, complexity and fragility to the binocular. The complex optical
path also leads to a narrow field of view and a large drop in brightness at high zoom. Models
also have to match the magnification for both eyes throughout the zoom range and hold
collimation to avoid eye strain and fatigue.
Night glasses are telescopes or binoculars with a large diameter objective. Large lenses can
gather and concentrate light, thus intensifying light with purely optical means and enabling
the user to see better in the dark than with the naked eye alone. Often night glasses also

2. have a fairly large exit pupil of 7 mm or more to let all gathered light into the user's eye.
However, many people can't take advantage of this because of the limited dilation of the
human pupil. To overcome this, soldiers were sometimes issued atropine eye drops to dilate
pupils. Before the introduction of image intensifiers, night glasses were the only method of
night vision, and thus were widely utilized, especially at sea. Second World War era night
glasses usually had a lens diameter of 56 mm or more with magnification of seven or eight.
Major drawbacks of night glasses are their large size and weight.
Digital camera binoculars are binoculars with digital camera capabilities. In these, the digital
binocular camera is situated on top and takes a photograph or a video of the view that is
seen through the binoculars. There is an LCD screen, either flat or flip-up, which allows the
users to frame the picture or video to be taken and review it afterward; the flip-up version is
generally the more convenient one.
Given the differences between the human eye and the camera lens, it is necessary to keep in
mind that the photographed or recorded view may not be exactly as the one seen through
the digital camera binocular eye-piece. The photo and video quality depends on how basic
or advanced the digital camera binoculars are, specifically on what the magnification is as
well as the size of the lens. These two factors are indicated by the binocular numbers, for
instance 8 by 42, where 8 is the magnification and 42 is the lens size. The larger the lens size,
the better the image. In advanced digital camera binoculars, the binocular numbers are large
and the photographs taken are good enough to be printed out.
Many binoculars with digital cameras only have limited storage space on their internal
memory. Once this memory gets full, if the digital camera binocular is to be used again, the
photographs and videos taken have to be either deleted or transferred elsewhere. They can
be downloaded onto a computer or stored on memory cards or on external memory drives.
In some cases, they can even be directly emailed or sent to an online photo site.
Usually, all digital camera binoculars come with image manipulation software that allows
users to re-size and adjust the downloaded photographs. Other general accessories can
include AAA batteries, USB cable, neck strap and tripod mounts. The last is particularly
useful for avoiding the pitfalls of handheld tremors in photographs and videos. Some digital
camera binoculars models have fold-down rubber eye-cups to make viewing easier for
people who wear glasses.
Binoculars with digital camera are popular with hikers, bird-watchers, nature researchers
and sports enthusiasts, among others. The basic, inexpensive digital camera binoculars,
however, are not well-suited for any in-depth observation. For serious study, it is necessary
to get the advanced digital camera binocular models that come with special close-focus and
magnification capabilities. Bird-watchers can train such models on birds, zoom in, and
capture specific bird behaviors instantly. Sports enthusiasts too can follow the action closely
and preserve the memorable moments.

3. Be it a concert, the Kentucky Derby, a political rally, football game or the opera, binoculars
can come in handy for just about any occasion where getting a closer view of an event is
needed. For these kinds of events, compact binoculars are ideal – small, robust, and
designed to fit into a handbag or jacket pocket. Compact binoculars are unobtrusive and
low-key, and do not need to be as robust or specialized as their hunting, birding or marine
cousins - although the basic principles behind them remain the same.
Like every other pair of binoculars, spectator binoculars consist of two identical, mirror-
symmetrical telescopes placed side-by-side and aligned together. This arrangement grants
observers an incredible depth of field and magnification while retaining the eye’s ability to
see objects in three dimensions, something which a monocular telescope is unable to do.
For most people, a pair of wide angle compact binoculars with magnifications levels that
range from 6x to 7x and objective lens sizes ranging from 25mm to 40mm should suffice.
Binoculars in this size range are normally lightweight, stable and easy to hold over long
periods of time. If you know you are likely to be seated, a set of binoculars with a
magnification of 10x will provide a crisp, close-up image of what you are trying to view. Try
not to go above 10x, as it will cause the image to suffer.
As you become more advanced and familiar with the use and handling of compact
binoculars you can begin to worry about things like magnification compared to objective
lens size. Objective lens size is a fairly simple choice to make - the larger the lens, the more
light will be collected and the sharper the final image will be. However, large lenses also
tends to lead to bulkier construction, and can be less manageable.
The best advice when buying compact binoculars is to use your own common sense and
judgment – how far away will you be from the stage or whatever you plan to look at? In a
standard concert hall, 10 x magnifications will probably be overkill. But if you were stood at
the back of the crowd at, say, President Osama's inauguration, then you may need the boost
to the viewing distance that a larger pair of binoculars can provide. If you pick a fairly mid-
powered pair of compact binoculars, the chances are that they will serve you well enough in
any given day-to-day situation.
Image-stabilized binoculars are binoculars that have a mechanism for decreasing the
apparent motion of the view due to binocular movement.
Image stabilized binoculars are designed to minimize image shaking in hand-held binoculars.
Higher power binoculars bring the image closer, but the image shift is also greater with even
smaller movement of your hands. Image stabilization technology in binoculars ensures
instant adjustment of the image to compensate for the motion. Major brands making image
stabilized binoculars include are Canon, Fujinon, Nikon, Carl Zeiss, and Bushnell.
Several different mechanisms have been used for image stabilization.
Binoculars with digital camera are the in thing as they can be used to take good pictures of
the objects that you are viewing. This helps as that will mean that you have the best of the
both the worlds. You get a good pair of binoculars as well you can have the best of the

4. pictures of the view that you were enjoying. That said there a few things that you need look
for the digital camera binoculars so that you derive the maximum benefit.
Digital camera binoculars have the optical zoom as well as the interpolation zoom. The
interpolation zoom is kind of a hypothetical zoom which assumes the image that you will see
and then gives you the result. The other one is the optical zoom which gives the actual zoom
of the binoculars and the camera that you will be able to view.
Always when reading the specifications of the binoculars with the built in digital camera you
can make sure that you have the optical zoom in mind. That way you can always get the
good digital binoculars or as people call it the dig bins.
Resolution of the camera is very important and that will mean that you be very careful about
what the specifications say. The digital cameras with low VGA are not very good. The low
VGA implies that you have the cameras with 1 mega pixel or less. That will not be very good
for picture quality but will be good for sending pictures via email.
Ideally you should be able to take small video clips using the digital camera. That will mean
that the digital camera that comes along with binoculars should have that capability to
replay the clips. A lot of binoculars come with the instant replay feature. Those binoculars
with instant replay feature are very good for seeing what you have shot and give you an
instant idea of the picture video quality. The best way to view these is to have the LCD
screen. Therefore now there are binoculars with LCD screens on them.
Another feature that should be there is the tripod adaptability. Taking pictures using the
tripod is a must so that you have the best of the pictures without the shakiness of the hand.
Make sure that those binoculars that you buy have a magnification of 8 or more. In fact
more is also not desirable as then binoculars can become heavy. Less is not desirable as then
you will not have good image quality.
Always make sure that the binoculars having a digital camera have a memory slot for an SD
card or MMC card. Most digital cameras with binoculars have the best the slot for the same
but again it is always better to make sure that it has one. Otherwise most of the inbuilt
memory is for 300 pictures approximately and then you will have to delete those or transfer
those to the PC.