Frequently Asked Questions
We carry a large variety of items from different brands. We have compiled
this page from questions that your questions have asked us in the past, and we
hope this may help you out a bit in picking the best products that will fit your
needs.
Binoculars:
Binoculars are some of the world's most common and frequently used optical tools.
A binocular consists of two optical systems mounted side by side, joined by a hinge,
and aligned to point accurately in the same direction, to be viewed through each of
the viewer's eyes. Binoculars have many uses, and once you own a good pair of binoculars,
you find more and more uses for them over time. Some of the most common include astronomy
binoculars, bird watching binoculars, hunting binoculars, marine binoculars, military
binoculars, sports binoculars, and theatrical binoculars (aka opera glasses).
The following basic definitions will show what the various features of binoculars mean.
Magnification (Power):
Binoculars are frequently described with two numbers, separated by "x". For
example, 8x25 or 10x50 binoculars. The first number represents the power, or
magnification of a binocular. With the 8x25 binocular, the viewed object will
appear eight times closer than it does if viewed with the naked eye. With the
10x50 binocular, the object viewed appears ten times closer.
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Objective Lens (Aperture):
The objective lens size is the second number in this formula, and it represents
the diameter of the front lens. The larger the objective lens is, the more light
will enter the binocular and the brighter its images will become.
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Prism Types:
The binocular prism system shrinks the size needed to keep a long optical path
and turns what would have been an upside-down image, right-side-up. Two main
prism system types are roof and porro.
* Roof prism binoculars have close overlapping prisms, which helps the objective
lenses to line up directly with the eyepiece. This results in a slender
streamlined shape, where the lenses and prisms are in a straight line. Roof
prism binoculars are more compact and rugged than an equivalent porro model.
* Porro prism binoculars make the objective or front lens offset from its
eyepiece. The porro prisms provide more depth perception and often a wider field
of view as well. Since its design is both simple and efficient, some of the best
values can be found with a porro design.
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Prism Glass:
Typically, the optical prisms are made from either borosilicate (BK-7) glass or
barium crown (BaK-4) glass. BaK-4 prism glass is considered the higher quality
glass, bringing brighter images with a sharper focus.
[back to binoculars section]
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Exit Pupil:
The size of the circle of light visible at the eyepiece of a binocular is
referred to as the exit pupil. The larger the exit pupil, the brighter the
viewed image can become. To find out the exit pupil, simply divide the objective
lens diameter of a binocular by its power. For example, an 8x32 binocular would
have an exit pupil of (32 divided by 8) 4mm.
[back to binoculars section]
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Diopter Adjustment:
The diopter adjustment is a fine focus adjustment ring that's usually located
around one eyepiece of the binoculars. It's there to compensate for any vision
differences between the right and left eye. Just turn the ring slowly to tune
the binoculars to your own two eyes.
[back to binoculars section]
[back to top]
Eye Relief:
The eye relief of a binocular measures how far an object can be held away from
the eye, but still be present in the full field of view. Binoculars with
extended or long eye relief reduce the strain on your eyes. If you wear
eyeglasses and/or spend long periods of time with your binoculars, a greater eye
relief will literally provide relief for your eyes.
[back to binoculars section]
[back to top]
Field of View (F.O.V.):
A binocular's field of view is the side-to-side measurement of the subject area
or the circular viewing field. It's defined by the width, in feet or meters, of
the area visible at the distance of 1000 yards or meters. Wide-angle binoculars
feature a wide field of view and are better for following action. For the most
part, the higher a binocular's magnification, the narrower its field of view
becomes. When you can see something specific too up-close, you simply won't be
able to view as much around it.
[back to binoculars section]
[back to top]
Durability:
There are binoculars which are o-ring sealed and nitrogen-purged for total
waterproof and fogproof protection. Such models can even be put under water, but
will remain dry on the inside. The interior lens surfaces won't fog up due to
rapid temperature or humidity changes. Rubber armor is another efficient way to
provide durability for your binoculars, and it has a few additional benefits.
For one, the comfortable gripping surface makes these binoculars easier to hold
onto. Also, it muffles the sound of any non-rubber objects bumping against it,
which keeps it from spooking wildlife.
[back to binoculars section]
[back to top]
Coating Types:
Coatings of the lens surface reduce the loss of light and minimize glare due to
reflection. This results in a brighter image that has higher contrast and less
eye strain. There are four basic types of lens coating.
* Coated - one layer of coating on at least one lens surface
* Fully Coated - one layer of coating on all air-to-glass lens surfaces
* Multi-Coated - multiple layers of coating on at least one lens surface
* Fully Multi-Coated - multiple layers of coating on all air-to-glass lens
surfaces
*Phase coating (aka Phase-corrected prism coating) and dielectric prism coating - effective techniques implemented recently (since 2005) for reducing reflections. Phase coated prisms improve the brightness and quality of their more basic anti-reflective (AR) coatings. Most of the time, phase corrected prisms work together with their already fully multi-coated lenses.
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Digital Cameras:
Similar to the standard film camera, digital imaging technology also uses a lens
to focus the image on a focal plane. As the film camera relies on a film to
capture the image, the digital equipment relies on a sensor. When the light
strikes an array of picture elements commonly referred to as pixels, which make
up the sensor, it is converted to a current that is then passed onto a digital
or A-D converter. From the A-D converter, algorithms are then applied to the
data, converting it to a digitized image file. Digital equipment is more
convenient and produces better quality than its predecessor, and most of the
latest models are also easier to use. Talk about a winning combination! The
following basic definitions will show what the various features of digital
cameras mean.
Digital Image Sensors:
Digital Imaging Sensors are silicon chips which contain rows of millions of tiny
photo diodes. These diodes convert light into an electronic signal. CCD and CMOS
are two types of sensors commonly used to capture images in digital cameras and
other digital equipment. Both can produce excellent results.
* CCD (Charge Coupled Device) is a sensor type generally used in the full-size
Instant Replay and the Outdoor Cameras.
* CMOS (Complementary Metal-Oxide Semiconductor) is a sensor type used in the
compact Instant Replay and in the Image View models of digital equipment.
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Pixels and Megapixels:
Pixels are the tiny squares of color, somewhat like the dots on a newspaper
photograph or grains on a photographic print, which combine together to make up
a digital image. The higher the pixel count, the higher the photographic
resolution, and the better the image quality. Of course, as image quality
increases, the size it takes up in storage also increases. One Megapixel (MP)
means one million pixels.
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Interpolation:
Interpolation is a method of increasing the number of pixels in an image after
it has been photographed. The pixels actually captured by the sensor of your
digital equipment are rapidly analyzed by software that creates and adds new
similar pixels to the photo file. Some optical images provide the user with
options for higher interpolated resolution settings, but all specifications are
listed at the true pixel count of the digital sensor, not an artificially
inflated count. In other words, there are many new digital cameras which help
increase the quality and zoom-ability of an already taken image.
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Resolution and File Size:
The total pixel count needed to make a digital photo is the primary factor that
will decide the resolution, or ability to reproduce fine detail. More pixels
simply mean a higher resolution, which also means a larger storage area for the
digital data file.
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File Compression & Quality :
In addition to high and low resolution settings, many digital cameras will give
the user options for selecting the Quality, or percentage of jpeg file
compression that is applied to photos that are stored in memory. Higher quality
settings use less compression, but take up more storage space. Before you play
with compression, make sure to keep a copy of the original. Then do some old
fashioned trial and error – 95%? 90%? 80%? Some photos will become more compact
but won’t lose any quality, while other photos will start losing quite a bit of
quality – just try the different compressions and let your eyes decide!
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Storage: Digital “Film”:
Storage cards are small removable “flash” memory devices which are used to hold
a digital camera’s image data. These cards reduce or eliminate the need for
high-capacity internal memory of a digital device. The vast majority of the
digital imaging optics has a storage card slot. The two most common types of
cards currently used in digital equipment are the SD (Secure Digital) and the CF
(Compact Flash) cards.
Cameras with USB Mass Storage don’t need a driver for Windows 2000/SP. When you
connect the camera to your PC, it will automatically be identified as a new
“Removable Disk”, just as if it were or an external zip drive or hard drive.
Your photo files get stored in a folder on this “Drive/Disk”. This data can be
copied or moved to the location of your choice, including your PC of course, or
it can be opened directly from the camera within your photo software. Most
digital equipment, especially the kind that connects to your PC, comes with
appropriate software already included with the purchase.
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Flash Memory:
Flash memory is a “non-volatile” kind of memory, which means it can retain the
photo files and user settings, even if the power source is removed for a long
period of time. Many cameras have electronic components to preserve the memory
contents for a few minutes, allowing a bit of time to change batteries. However,
it is always a good idea to download your latest photos onto your computer
before changing batteries or storing the camera away for several weeks.
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Focus Systems:
One of the three main methods of focusing is typically used in digital cameras.
Digital equipment can use the Fixed Focus, Auto Focus or Manual Focus system.
Fixed Focus: The lens is fixed in place, and optimized for maximum depth of
field (zone of apparent focus). Works well for distant subjects such as
spectator sports (but lacks close focus capability), and rapidly moving subjects
it may sometimes be difficult to maintain focus with other systems. (All Image
View models and Compact Instant Replay, 110718 has dual zone near/far focus)
Auto Focus: Electronics calculate the distance to the subject based on contrast
detection or by an infrared beam, then a motor rotates the lens to the
appropriate focus position. (Outdoor Cameras)
Manual Focus: Allows the user to freely set focus, usually by rotating a knob or
the lens barrel. Requires more user interaction, but often yields the sharpest
results, and allows the user to determine and quickly change the primary subject
of interest. (Full size Instant Replay and 11-8000 Digital Monocular)
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Camera Settings:
The “default” automatic setting on digital cameras work fine in most situations,
but some cameras will also let the user override “auto” and adjust one or more
of the following if necessary or preferred:
EV (Exposure Value): also known as exposure compensation. Allows setting
deliberate under or over exposure by a fine amount, such as “+1.5 EV” (one and a
half steps overexposed)
ISO (Sensitivity): As with film, low ISO numbers (100-200) will produce the
highest quality but require the most light. Higher ISO settings will allow
photos in low light without flash, or faster shutter speeds to stop action, but
with increasingly noticeable digital “noise”.
Scene Presets: Some cameras let the user select from several preprogrammed “scenes”, which
optimize internal camera settings (aperture, shutter speed, point of focus,
light metering) for common types of subjects or situations, most commonly:
Landscape, Sports/Action, Portrait, and Night Scene.
White Balance: Auto white balance electronics identify a white reference point
(wall, clouds, etc) in a scene and apply overall color correction if needed, so
the whites retain a neutral appearance. If this produces poor results, user
presets for daylight, cloudy, tungsten and fluorescent bulb lighting are often
available.
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Special Features:
Self Timer-when this feature is selected, the photo is taken following a short
delay after the shutter button is pressed. Used to prevent camera shake, or to
include yourself in the photo.
Sequential Shot – shoots a quick burst of multiple frames (usually 3-5 in a
row), to increase chances of capturing the peak of the action.
Macro Focus – a close focus setting that allows the user to fill the frame with
a small object, often only a few inches from the lens
Movie Mode – allows the camera to shoot and playback short video or “movie”
clips. These are usually stored in the common “avi” format, and can be played
back on any computer with Windows Media Player, QuickTime, or other widely
available software.
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Waterproof and Weatherproof:
The Bushnell Outdoor Camera is designed to be water resistant, or
“weatherproof”. This means that it will not be damaged by rain (short of a
monsoon!) or accidental splashes of water at the lake. It is not intended to be
fully submerged in water or used by divers, but will withstand conditions
commonly encountered by campers, hikers and other outdoor enthusiasts who may be
reluctant to risk an expensive “chrome” camera on their outing. The Outdoor
camera is also shock resistant and features rubber grips for secure handling.
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Magnifiers:
Do you need to examine something detailed, well, in detail? Reading some small
print before you sign it, or just trying to make it easier for yourself to
read a small-printed book? Perhaps you’re trying to get a closer look at a
catalog or a photo album? Either way, what you’ll need is a good magnifier
to help make it all easier on your eyes. Magnifiers can have other uses as
well – use it at school, home, office, or take it with you wherever you go.
The following basic definitions will show what the various features of
magnifiers mean.
Magnification (Power):
Just as many other optical devices, a magnifier has a magnification
rating which is followed by “x”. For example, 2x or 3x magnifiers.
The 2x magnifier means it will show you things twice as large as
they would normally appear, and the 3x magnifier means it will
enlarge the images by three times.
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Spot Lens (Another Power):
Some magnifiers also have a spot lens, which is an additional
smaller magnifier, usually located inside the first magnifier.
The spot lens always has a higher power than the general
magnifier, for when you encounter extra tiny print or extra
tiny details.
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Dimensions:
The dimensions of a magnifier are simply its size. The
height, length and width determine a magnifier’s dimensions.
In some cases it’s only height and length because the width
is relatively thin with many magnifiers. Some people consider
the smaller ones more portable and convenient. Others consider
the larger ones more comfortable for long-term use. It’s often
a good idea to purchase more than one magnifier if you have
more than one different use for the magnifiers to fulfill.
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Weight:
The weight of a magnifier is just that – how much it weighs.
Some people prefer lighter magnifiers for portability.
Others need to use their magnifiers to see a larger area so
they go with the heavier ones. Much like the dimensions, it’s
about preference as well as about what you’ll be using your
magnifier for and whether you’ll be using the magnifier for
long periods of time.
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Monoculars:
Monoculars are some of the world's most common and frequently
used optical tools. A monocular consists of one optical tube, to
be viewed through one of the viewer's eyes. Monoculars have many
uses, and once you own a good monocular or two, you find more and
more uses for them over time. Some of the most common include
astronomy monoculars, bird watching monoculars, hunting monoculars,
marine monoculars, military monoculars, sports monoculars, and
theatrical monoculars (aka opera monoculars). The following basic
definitions will show what the various features of monoculars mean.
Magnification (Power):
Monoculars are frequently described with two numbers, separated
by "x". For example, 8x25 or 10x50 monoculars. The first number
represents the power, or magnification of a monocular. With the
8x25 monocular, the viewed object will appear eight times closer
than it does if viewed with the naked eye. With the 10x50
monocular, the object viewed appears ten times closer.
[back to monocular section]
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Objective Lens (Aperture):
The objective lens size is the second number in this formula,
and it represents the diameter of the front lens. The larger the
objective lens is, the more light will enter the monocular and
the brighter its images will become.
[back to monocular section]
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Prism Types:
The monocular prism system shrinks the size needed to keep
a long optical path and turns what would have been an upside-down
image, right-side-up. Two main prism system types are roof and porro.
* Roof prism monoculars have close overlapping prisms, which helps
the objective lenses to line up directly with the eyepiece. This
results in a slender streamlined shape, where the lenses and prisms
are in a straight line. Roof prism monoculars are more compact and
rugged than an equivalent porro model.
* Porro prism monoculars make the objective or front lens offset from
its eyepiece. The porro prisms provide more depth perception and often
a wider field of view as well. Since its design is both simple and
efficient, some of the best values can be found with a porro design.
[back to monocular section]
[back to top]
Prism Glass:
Typically, the optical prisms are made from either borosilicate
(BK-7) glass or barium crown (BaK-4) glass. BaK-4 prism glass is
considered the higher quality glass, bringing brighter images
with a sharper focus.
[back to monocular section]
[back to top]
Exit Pupil:
The size of the circle of light visible at the eyepiece of a
monocular is referred to as the exit pupil. The larger the
exit pupil, the brighter the viewed image can become. To find
out the exit pupil, simply divide the objective lens diameter of
a monocular by its power. For example, an 8x32 monocular would
have an exit pupil of (32 divided by 8) 4mm.
[back to monocular section]
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Diopter Adjustment:
The diopter adjustment is a fine focus adjustment ring that's
usually located around one eyepiece of the monoculars. It's there
to compensate for any vision differences between the right and
left eye. Just turn the ring slowly to tune the monoculars to
your own two eyes.
[back to monocular section]
[back to top]
Eye Relief:
The eye relief of a monocular measures how far an object can
be held away from the eye, but still be present in the full
field of view. Monoculars with extended or long eye relief
reduce the strain on your eyes. If you wear eyeglasses and/or
spend long periods of time with your monoculars, a greater eye
relief will literally provide relief for your eyes.
[back to monocular section]
[back to top]
Field of View (F.O.V.):
A monocular's field of view is the side-to-side measurement
of the subject area or the circular viewing field. It's defined
by the width, in feet or meters, of the area visible at the distance
of 1000 yards or meters. Wide-angle monoculars feature a wide field
of view and are better for following action. For the most part, the
higher a monocular's magnification, the narrower its field of view
becomes. When you can see something specific too up-close, you simply
won't be able to view as much around it.
[back to monocular section]
[back to top]
Durability:
There are monoculars which are o-ring sealed and nitrogen-purged
for total waterproof and fogproof protection. Such models can even
be put under water, but will remain dry on the inside. The interior
lens surfaces won't fog up due to rapid temperature or humidity changes.
Rubber armor is another efficient way to provide durability for your
monoculars, and it has a few additional benefits. For one, the comfortable
gripping surface makes these monoculars easier to hold onto. Also, it
muffles the sound of any non-rubber objects bumping against it, which
keeps it from spooking wildlife.
[back to monocular section]
[back to top]
Coating Types:
Coatings of the lens surface reduce the loss of light and minimize
glare due to reflection. This results in a brighter image that has
higher contrast and less eye strain. There are four basic types of
lens coating.
* Coated - one layer of coating on at least one lens surface
* Fully Coated - one layer of coating on all air-to-glass lens surfaces
* Multi-Coated - multiple layers of coating on at least one lens surface
* Fully Multi-Coated - multiple layers of coating on all air-to-glass lens surfaces
* Phase coating (aka Phase-corrected prism coating) and dielectric prism coating - effective techniques implemented recently (since 2005) for reducing reflections. Phase coated prisms improve the brightness and quality of their more basic anti-reflective (AR) coatings. Most of the time, phase corrected prisms work together with their already fully multi-coated lenses.
[back to monocular section]
[back to top]
Radar Detectors:
Radar guns operate by transmitting radio waves at certain
frequencies which reflect off objects (your vehicle) and are then picked
up by the radar gun's receiving section. When radar waves reflect off
a moving target, a measurable frequency shift occurs. The radar unit
converts this shift into miles per hour to determine the target's speed.
For example, a target is 1 mile away this second, and the next second
it registers as 1.01 miles away. So, 0.01 x 60 (seconds) x 60 (minutes) =
36 miles per hour – the target is moving away from the radar gun at the
speed of 36 miles per hour. This is, of course, a rather simplified example.
Also, the distance is checked (and re-checked) by the radar gun more than once
per second, but the basic principle of a radar gun works along those lines.
A radar detector is a radio receiver tuned to specific frequencies used by
police radar. In other words, a radar detector is a device that can look for
these radio waves in different specific directions. Radar detectors are
extremely sensitive – they have to be, and are often able to hear radar waves
from over a mile away, far beyond the range at which radar can clock a vehicle's
speed. In evaluating a radar detector, the two most important performance criteria
are sensitivity and selectivity. Sensitivity is a measure of a unit’s detection
range. Selectivity refers to a unit's ability to reject non-police microwave
signals and is an important feature because of the many sources of "electronic
pollution". Automatic door openers and some burglar alarms operate on X-band,
which is a police band. A radar detector cannot tell if a store is opening a
door or a police officer is checking speed. In older times, electronic pollution
used to be a much larger problem, but as the radar detectors became more sensitive
and accurate, the problems diminished significantly. The following basic
definitions will show what the various features of radar detectors mean.
Series (Radar and Laser):
A laser speed gun’s waves transmit short bursts of invisible light which
bounce off a target vehicle and return to the laser gun. By timing the outgoing
and return trips of the light bursts, it can compute the target's speed.
The laser's biggest selling point is its narrow beam-only about three feet wide
at a distance of 1,000 feet - a feature that provides nearly foolproof target
identification. In comparison, the beam of a radar is about 250 feet wide at 1,000 feet.
Laser guns must be used from stationary position and are most effective at short range,
usually when targeting traffic at 600 to 1,200 feet.
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360 Degree Detection:
Most laser radar detectors have this feature now-a-days, and are simply
able to detect the radar gun’s waves, regardless of whether the police are
in front of you, behind you, or at any angle.
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Bands (X, K, Ka, Ku, etc):
The X band is one of the most frequent frequencies, no pun intended. It used
to be the only radar gun frequency until the mid 1970’s when the K band was
introduced. There’s also Stalker and BEE which are covered by wideband radar
detectors, and the Superwideband covers a larger band of wavelengths. To make
it simple, -- sounds are actually waves. These very tiny waves are not heard
by human ears, and are measured in tens of thousands of gigahertz
(1 GHz = 1,000,000,000 Hz) (10,000 GHz = 10,000,000,000,000 Hz). Easy to
understand why they’re referred to as MICRO waves and why humans can’t hear them.
Different wave bands, or frequencies, can be used for a multitude of purposes,
which is why a radar detector needs to be quite sensitive to specific radar gun
frequencies, so that it doesn’t bother you for most other electronic devices.
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VG-2:
A Radar Detector Detector (RDD) is a microwave receiver used by police to
detect signals radiated by the local oscillator (A circuit inside the detector)
of a radar detector. The trade name of the commonly used RDD manufactured is
Interceptor VG-2, most often just referred to as VG-2. Simply put, you know they’re
clocking you but thanks to the Interceptor VG-2, they don’t know you know – they
don’t know if you have a radar detector.
NOTE: It is the responsibility of the individual radar detector owner to know and
understand the laws in his or her area regarding the legality of the use of radar
detector features.
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Radar Guns:
Radar guns operate by transmitting radio waves at certain frequencies
which reflect off objects (your vehicle) and are then picked up by the radar gun's
receiving section. When radar waves reflect off a moving target, a measurable
frequency shift occurs. The radar unit converts this shift into miles per hour to
determine the target's speed. For example, a target is 1 mile away this second,
and the next second it registers as 1.01 miles away. So, 0.01 x 60 (seconds) x 60 (
minutes) = 36 miles per hour – the target is moving away from the radar gun at the
speed of 36 miles per hour. This is, of course, a rather simplified example. Also,
the distance is checked (and re-checked) by the radar gun more than once per second,
but the basic principle of a radar gun works along those lines. The following basic
definitions will show what the various features of radar guns mean.
Accuracy:
The accuracy of a radar gun is simply how accurately it can tell the speed
of the target you’re measuring. Most modern radar guns available to the public
have an accuracy rating of +/-1 mph at +/- 2 degrees of being directly behind
or directly in front of the target. As you get more “to the side” of the
target, your readout gets less accurate.
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Readout:
A radar gun’s readout can be in MPH (miles per hour) and/or KPH (kilometers per hour).
There are radar guns which have both. There are also radar gun kits which come
with large readout displays, for more viewing convenience.
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Range:
The range of a radar gun is simply the minimum speed to maximum speed which it detects.
For example, if the target is moving less than 6 miles per hour, most radar guns may
not detect it. Alternatively, if the target is moving over 200 miles per hour, most
radar guns would give an incorrect reading.
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Modes:
* The Trigger Mode is a common radar gun feature where you press the trigger and watch the readout.
* The Continuous Mode is only available in a few radar guns, and it’s a feature that enables
you to take readings without constantly holding onto the radar gun.
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Range Finders:
A laser range finder is a distance measuring instrument used to
calculate the distance to targeted objects. The accuracy of a laser rangefinder
is normally +/- 1 yard, and the distance is displayed instantly on a built-in
LCD (Liquid Crystal Display) screen. These laser range finders have many uses,
golf being one of the most frequent but certainly not the only one. Wherever
large distances between you and another target need to be measured, a laser
range finder will save quite a bit of time and hassle. The following basic
definitions will show what the various features of range finders mean.
Magnification (Power):
Range Finders, like many optical devices, are frequently described with two numbers,
separated by "x". For example, 4x20 or 7x40 range finders. The first number represents
the power, or magnification of a range finder. With the 4x20 range finder, the
viewed object will appear four times closer than it does if viewed with the naked eye.
With the 7x40 binocular, the object viewed appears seven times closer.
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Objective Lens (Aperture):
The objective lens size is the second number in this formula, and it
represents the diameter of the front lens. The larger the objective lens is,
the more light will enter the binocular and the brighter its images will become.
[back to range finders section]
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Field of View (F.O.V.):
A range finder's field of view is the side-to-side measurement of the subject area
or the circular viewing field. It's defined by the width, in feet or meters, of the
area visible at the distance of 1000 yards or meters. For the most part, the higher a
rangefinder's magnification, the narrower its field of view becomes. When you can see
something specific too up-close, you simply won't be able to view as much around it.
[back to range finders section]
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Targeting Modes:
Some range finders feature selective targeting modes to help detect more specific targets.
* STANDARD WITH AUTOMATIC SCAN is a range finder mode that will scan across the course while
viewing a continuously updated LCD display of the distance between you and your target.
* BULLSEYE is a range finder mode geared for close-range use, acquiring the distances of small
targets and game without accidentally picking up background target distances. When more than one
object is acquired by the range finder, the closer of the two objects is shown on the LCD display.
* BRUSH ignores the foreground, such as brush trees and bushes, boulders and tree branches. This
range finder mode provides distances on the LCD display to background objects only.
* PIN SEEKER is a range finder mode designed exclusively for golf, with the bottom of the cup in mind.
This mode allows easy acquisition of the flag without inadvertently capturing background target distances.
When more than one object is acquired, the closer of the two objects is shown on the LCD display.
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Measuring Range:
A range finder’s measuring range is the range between the smallest and the largest distance
the range finder can detect. For example, most rangefinders will not find a target that’s only
ten feet ahead or over fifteen hundred feet in the distance. This is a general range and does
not represent any specific range finder, check the specific rangefinder’s information for its
range capabilities.
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Max Distance:
The maximum distance is simply the farthest distance a range finder can detect the target.
Most of the time, a lighter object can be seen from farther away by the laser range finder,
while a darker one can not. Also, since it’s not a night vision device, a regular range
finder cannot see in total darkness.
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Rifle Scopes:
Rifle Scopes are some of the world's most common and frequently used optical tools. A rifle scope
consists of two optical systems mounted side by side, joined by a hinge, and aligned to point
accurately in the same direction, to be viewed through each of the viewer's eyes. Rifle Scopes
have many uses, and once you own a good pair of rifle scopes, you find more and more uses for them
over time. Some of the most common include astronomy rifle scopes, bird watching rifle scopes,
hunting rifle scopes, marine rifle scopes, military rifle scopes, sports rifle scopes, and
theatrical rifle scopes (aka opera glasses). The following basic definitions will show what the
various features of rifle scopes mean.
Magnification (Power):
Rifle Scopes are frequently described with two numbers, separated by "x". For example,
4x32 or 3-9x32 riflescopes. The first number represents the power, or magnification of
a rifle scope. With the 4x32 rifle scope, the viewed object will appear four times
closer than it does if viewed with the naked eye. With the 3-9x32 rifle scope, the
object viewed can appear from three to nine times closer.
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Objective Lens (Aperture):
The objective lens size is the second number in this formula, and it represents
the diameter of the riflescope’s front lens. The larger the objective lens is,
the more light will enter the rifle scope and the brighter its images will become.
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Exit Pupil:
The size of the circle of light visible at the eyepiece of a rifle scope is
referred to as the exit pupil. The larger the exit pupil, the brighter the viewed
image can become. To find out the exit pupil, simply divide the objective lens
diameter of a rifle scope by its power. For example, a 4x32 rifle scope would
have an exit pupil of (32 divided by 4) 8mm.
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Eye Relief:
The eye relief of a rifle scope measures how far an object can be held away
from the eye, but still be present in the full field of view. Rifle Scopes with
extended or long eye relief reduce the strain on your eyes. If you wear eyeglasses
and/or spend long periods of time with your rifle scopes, a greater eye relief
will literally provide relief for your eyes.
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Field of View (F.O.V.):
A rifle scope's field of view is the side-to-side measurement of the subject
area or the circular viewing field. It's defined by the width, in feet or meters,
of the area visible at the distance of 1000 yards or meters. When you can see
something specific too up-close, you simply won't be able to view as much around it.
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Parallax:
The parallax is a condition that occurs when the image of the target is not focused
precisely on the reticle plane. Parallax of a rifle scope is visible as an apparent
movement between the reticle and the target when the shooter moves their head or,
in extreme cases, as an out-of-focus image. Some of the more modern riflescopes are
factory designed to be parallax free at 100 yards, and some even at 50 yards.
Scopes of 11x or more generally have an adjustable objective to help adjust for parallax.
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Adjustments (Windage and Elevation):
The windage and elevation are a rifle scope’s precision adjustments that affect accuracy.
Windage is the horizontal (left-to-right) adjustment, usually the side turret of the scope.
Elevation is the vertical (up-and-down) adjustment, usually the top turret of the scope.
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Reticles:
A riflescope’s reticle is the crosshair or pattern placed on the eye of the scope, which
establishes the weapon’s position on the target. Some of the reticle types include Multi-X,
Circle-X, Mil FireFly, M.O.A. and Mil Dot. The choice of reticle generally depends on the scope,
the weapon, the game, and of course, the personal preference of the user.
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Durability:
There are rifle scopes which are o-ring sealed and nitrogen-purged for total waterproof and
fogproof protection. Such models can even be put under water, but will remain dry on the inside.
The interior lens surfaces won't fog up due to rapid temperature or humidity changes. Rubber armor
is another efficient way to provide durability for your rifle scopes, and it has a few additional
benefits. For one, the comfortable gripping surface makes these rifle scopes easier to hold onto.
Also, it muffles the sound of any non-rubber objects bumping against it, which keeps it from spooking
wildlife.
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Coating Types:
Coatings of the lens surface reduce the loss of light and minimize glare due to reflection.
This results in a brighter image that has higher contrast and less eye strain. There are
four basic types of lens coating.
* Coated - one layer of coating on at least one lens surface
* Fully Coated - one layer of coating on all air-to-glass lens surfaces
* Multi-Coated - multiple layers of coating on at least one lens surface
* Fully Multi-Coated - multiple layers of coating on all air-to-glass lens surfaces
* Phase coating (aka Phase-corrected prism coating) and dielectric prism coating - effective techniques implemented recently (since 2005) for reducing reflections. Phase coated prisms improve the brightness and quality of their more basic anti-reflective (AR) coatings. Most of the time, phase corrected prisms work together with their already fully multi-coated lenses.
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Spotting Scopes:
The spotting scope is a high-powered compact optical instrument that’s used to view
distant objects. The two main categories are scopes used to view Earth objects and scopes
used to view into space - terrestrial spotting scopes and astronomical telescopes.
Spotting Scopes and Monoculars are made to bring far-away land based objects closer to the
viewer. Usually, a spotting scope offers more of a stable foundation than a binocular,
with the high magnification of a telescope. There are many different spotting scopes,
ideally suited for different activities like long distance bird and whale watching,
telephotography, nature studies, scenic observation, beginning astronomy, surveillance
and more. The following basic definitions will show what the various features of spottingscopes
mean.
Magnification (Power):
Spotting Scopes are frequently described with two numbers, separated by "x".
For example, 15-45x60 spotting scope. The first number represents the power,
or magnification of a spotting scope. With the 15-45x60 variable power spotting
scope, the viewed object will appear fifteen to forty five times closer than
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Objective Lens (Aperture):
The objective lens size is the second number in this formula, and it
represents the diameter of the objective or front lens. The larger the objective
lens is, the more light will enter the spotting scope and the brighter
its images will become.
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Prism Types:
The spotting scope prism system shrinks the size needed to keep a long
optical path and turns what would have been an upside-down image,
right-side-up. Two main prism system types are roof and porro.
* Roof prism spotting scopes have close overlapping prisms, which helps the objective
lenses to line up directly with the eyepiece. This results in a slender streamlined
shape, where the lenses and prisms are in a straight line. Roof prism spotting
scopes are more compact and rugged than an equivalent porro model.
* Porro prism spotting scopes make the objective or front lens offset from its eyepiece.
The porro prisms provide more depth perception and often a wider field of view as well.
Since its design is both simple and efficient, some of the best values can be found
with a porro design.
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Prism Glass:
Typically, the optical prisms are made from either borosilicate (BK-7) glass or
barium crown (BaK-4) glass. BaK-4 prism glass is considered the higher quality
glass, bringing brighter images with a sharper focus.
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Exit Pupil:
The size of the circle of light visible at the eyepiece of a spotting scope is
referred to as the exit pupil. The larger the exit pupil, the brighter the viewed
image can become. To find out the exit pupil, simply divide the objective lens
diameter of a spotting scope by its power. For example, a 15x60 spotting scope
model would have an exit pupil of (60 divided by 15) 4mm.
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Near or Close Focus:
The Near or Close Focus is a measurement of how close you can get to an object
while still retaining visual clarity and quality. A better Close Focus allows the
spotting scope to have more flexibility in viewing the objects comfortably in
virtually any situation.
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Eye Relief:
The eye relief of a spotting scope measures how far an object can be held away
from the eye, but still be present in the full field of view. Spotting Scopes
with extended or long eye relief reduce the strain on your eyes. If you wear
eyeglasses and/or spend long periods of time with your scopes, a greater eye
relief will literally provide relief for your eyes.
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Field of View (F.O.V.):
A spotting scope’s field of view is the side-to-side measurement of the
subject area or the circular viewing field. It's defined by the width, in feet
or meters, of the area visible at the distance of 1000 yards or meters. The
spotting scopes that feature a wide field of view are better for following
action or a moving object. For the most part, the higher a spotting scope's
magnification, the narrower its field of view becomes. When you can see
something specific too up-close, you simply won't be able to view as much
around it.
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Durability:
There are spotting scopes which are o-ring sealed and nitrogen-purged for total
waterproof and fogproof protection. Such models can even be put under water,
but will remain dry on the inside. The interior lens surfaces won't fog up
due to rapid temperature or humidity changes.
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Coating Types:
Coatings of the lens surface reduce the loss of light and minimize glare
due to reflection. This results in a brighter image that has higher contrast
and less eye strain. There are four basic types of lens coating.
* Coated - one layer of coating on at least one lens surface
* Fully Coated - one layer of coating on all air-to-glass lens surfaces
* Multi-Coated - multiple layers of coating on at least one lens surface
* Fully Multi-Coated - multiple layers of coating on all air-to-glass lens surfaces
* Phase coating (aka Phase-corrected prism coating) and dielectric prism coating - effective techniques implemented recently (since 2005) for reducing reflections. Phase coated prisms improve the brightness and quality of their more basic anti-reflective (AR) coatings. Most of the time, phase corrected prisms work together with their already fully multi-coated lenses.
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Resolution:
The definition or resolution of a spotting scope is simply its ability to show
fine detail and retain image clarity at the same time.
it does if viewed with the naked eye.
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Telescopes:
The word “telescope” comes from the Greek “tele” which means “far”, and “skopein”
which means to look or see. Telescopos literally means “far-seeing”, and in modern
times refers to optical telescopes. An optical telescope is a tool used to view
objects located at very far distances. These devices work by using one or more
curved optical elements, such as lenses or mirrors. They gather light or other
electromagnetic radiation, and bring that radiation or light into focus, so that
distant images can be viewed, photographed and studied. The two main categories are
scopes used to view Earth objects and scopes used to view into space - terrestrial
spotting scopes and astronomical telescopes. The following basic definitions will
show what the various features of telescopes mean.
Magnification (Power):
Telescopes are frequently described with two numbers, separated by "x". For example:
100x5. The first number represents the power, or magnification of a telescope. With the
100x5 telescope, the viewed object will appear one hundred times closer than it does if
viewed with the naked eye. A telescope’s magnification is calculated by dividing its focal
length by the focal length of the eyepiece being used on this telescope. For example, a
500mm telescope that uses a 5mm eyepiece would have the magnification of 100x. This way,
a telescope can provide nearly any magnification required, depending on the focal length
of the eyepiece being used. Because many objects in the sky are rather large as it is,
magnification that’s too high isn’t usually necessary. To make dim objects appear brighter
and sharper focus, you’d need a telescope that gathers lots of light. The scope’s
magnification or power contributes to the overall bulk and size of that telescope. A higher
power simply requires greater physical size of the objective lens being used.
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Objective Lens (Aperture):
The objective lens size is the second number in this formula, and it represents the
diameter of the objective lens or mirror. The larger the objective lens is, the more
light will enter the binocular and the brighter its images will become. The telescope’s
objective lens size, or aperture, limits the amount of power that can be effectively
used. When the magnification of an object increases, the brightness of the image diminishes.
This is like bringing your hand closer to your eyes to view the details of your palm – once
your hand is too close, it covers all the light and all you see is darkness. Peek-a-boo!
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Types of Telescopes:
Telescopes are generally one of the three types of optical systems: Refractor, Reflector,
and Maksutov-Cassegrain.
* The Refractor telescope is an optical system that uses a series of glass lenses to bend or refract
the light from a distant object in a way that it can be focused to a point and magnified by the
eyepiece. Made popular by Galileo in the 17th century, it’s also sometimes called a Galilean Refractor.
* The Reflector telescope is an optical system that utilizes a primary mirror to reflect light
\from a distant object in a way that it can be focused to a point and magnified by an eyepiece.
Made popular by Sir Isaac Newton in the 17th century, it’s also sometimes called a Newtonian Reflector.
* The Maksutov-Cassegrain telescope is a design that uses a curved lens element together with a
primary mirror that’s spherically curved in a similar way. This optical system configuration of a
telescope provides quality sharp images in a compact folded-light path package. The entire system
can now give a focal length much greater than the optical tube body length itself.
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Types of Lenses:
The two most frequently used telescope lens types are Barlow Lens and Erecting Lens. The Barlow
Lens is an auxiliary “helper-lens” that raises the power by a certain factor. For example, a
2x Barlow doubles the magnification of a telescope. Erecting Lenses are used with a refractor
telescope for viewing terrestrial land-based objects, and it turns the normally upside-down
image provided by a telescope, right-side-up.
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Finderscope:
On many of the astronomical telescopes, a lower powered Finderscope with
a wide field of view, allows users to quickly find the object they want to see
with a high-magnification main telescope. The finderscopes can be optical
or red dot.
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Focal Length:
The Focal Length of a telescope is the measured light path of the optical system,
which is usually also the Tube Length. A telescope’s focal length is typically
measured in millimeters.
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Focusing Knob:
The telescope’s focusing knob controls the focusing system. It allows for smooth
movement of the eyepiece, which results in sharp and precise images.
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Resolution:
The resolution, or definition of a telescope is simply its ability to show fine
detail and retain image clarity at the same time.
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Telescope Selection:
During telescope selection, it’s important to keep in mind which target
objects you intend to view, as well as your experience level. Most of the
night sky objects need to be viewed by a telescope that has as much
aperture, or power, as possible. But remember that as the size of the objective
lens or mirror increases, so does the size of the telescope. It’s a good idea to
select a telescope that isn’t too heavy for you to manage, and isn’t too
complicated for you to set up. Last but not least, make sure you have an idea
of whether your telescope will need to be portable, or whether it’s rarely
going to be moved.
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Types of Mounts:
The two three most frequently used types of telescope mounts are
Altitude-Azimuth (or Altaz) mount, the Equatorial Mount, and the Tripod Mount.
* Ideal for beginner astronomers, the Altaz mounts are the easiest to maneuver. They
come complete with either manual control or a motor drive that lets you follow an
object’s movement across the night sky. Altaz mounts move up-down and left-right.
* The Equatorial Mounts are more suited for the more experienced astronomers. It’s
an advanced telescope mount that’s tilted to compensate for rotation of the Earth.
* A Tripod Mount can become a steady platform for the telescope to be used virtually
hands-free. Because telescopes have such powerful magnification, even the smallest
shaking motion can be enough to move the telescope from its target. Tripods have
three adjustable legs which allow the telescope to be used even when the ground is uneven.
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Night Vision:
Night Vision technology enables you to see objects clearly at night or in darkened areas, at distances of up to
several hundred yards, in the absence of any artificial light. People, buildings, vehicles and details of the
landscape viewed through modern Night Vision Binoculars, Night Vision Monoculars, Night Vision Goggles or any other
night vision devices appear almost as if illuminated, while the same objects viewed with a naked eye would appear
only as indistinct shadows or won't be visible at all.
In order to better understand how most night vision technology works, compare a night vision device to a very
special video camera with an extremely high sensitivity to light. All night vision systems provide the viewer with
electronically enhanced viewing. When you use a night vision scope, you are not actually viewing the scene before
you, but instead you are viewing an enhanced video image of that scene.
Magnification (Power):
Just as most other optics, night vision devices are frequently described with two numbers, separated by "x".
The 1.5x20 Night Vision Goggles and the 4x60 Night Vision Binoculars are two such examples. The first number
represents the power, or magnification of a binocular. With the 4x60 night vision binocular, the viewed object will
appear four times closer than it does if viewed with the naked eye. With the 1.5x20 night vision goggles, the object
viewed appears one and a half times closer.
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Objective Lens (Aperture):
The objective lens size is the second number in this formula, and it represents the diameter of the front lens.
Normally, the larger the objective lens is, the more light will enter the optical and the brighter its images will
become. However, with night vision devices, an image intensifier tube’s function is far more responsible for making
the imagery brighter.
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Prism Types:
The night vision binocular prism system, much like a regular binocular’s, shrinks the size needed to keep a
long optical path and turns what would have been an upside-down image, right-side-up. Two main prism system types
are roof and porro.
* Roof prism night vision binoculars have close overlapping prisms, which helps the objective lenses to line up
directly with the eyepiece. This results in a slender streamlined shape, where the lenses and prisms are in a
straight line. Roof prism binoculars are more compact and rugged than an equivalent porro model.
* Porro prism night vision binoculars make the objective or front lens offset from its eyepiece. The porro prisms
provide more depth perception and often a wider field of view as well. Since its design is both simple and
efficient, some of the best values can be found with a porro design.
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Prism Glass:
Typically, the optical prisms are made from either borosilicate (BK-7) glass or barium crown (BaK-4) glass.
BaK-4 prism glass is considered the higher quality glass, bringing brighter images with a sharper focus.
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Exit Pupil:
The size of the circle of light visible at the eyepiece of a night vision device is referred to as the exit
pupil. With most optical devices – the larger the exit pupil, the brighter the viewed image can become – but with
night vision devices, that brightness is only part of the initial image, not the enhanced image. It’s still up to
the image intensifier tube to enhance the darkened view. To find out the exit pupil, simply divide the objective
lens diameter of a night vision device by its power. For example, a 4x60 night vision binocular would have an exit
pupil of (60 divided by 4) 15mm.
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Diopter Adjustment:
The diopter adjustment is a fine focus adjustment ring that's usually located around one eyepiece of the night
vision optical device. It's there to compensate for any vision differences between the right and left eye. Just turn
the ring slowly to tune the night vision device to your own two eyes.
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Eye Relief:
The eye relief of a night vision binocular measures how far an object can be held away from the eye, but still
be present in the full field of view. Night vision binoculars with extended or long eye relief reduce the strain on
your eyes. If you wear eyeglasses and/or spend long periods of time with your night vision binoculars, night vision
goggles or other night vision devices, a greater eye relief will literally provide relief for your eyes.
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Field of View (F.O.V.):
The field of view of a night vision device, much like with other optical equipment, is the side-to-side
measurement of the subject area or the circular viewing field. It's defined by the width, in feet or meters, of the
area visible at the distance of 1000 yards or meters. For the most part, the higher a night vision optical device’s
magnification, the narrower its field of view becomes. When you can see something specific too up-close, you simply
won't be able to view as much around it.
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Automatic Brightness Control (ABC):
Automatic Brightness Control in a night vision device is an electronic feature that automatically reduces
voltage to the micro channel plate to keep the image intensifier's brightness within optimal limits and protect the
tube. As the result of this image would get brighter and then, after a momentary delay, suddenly dim to a constant
level during the rapidly changing conditions from low-light to high-light. In other words, if it suddenly becomes
too bright, the sudden light change will not harm you or the optics, thanks to automatic brightness control. Note
that there can also be dirt or debris between the lenses, which can prevent optimal clarity and should be removed by
careful cleaning if the system designed with interchangeable optics.
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Bright - Source Protection (BSP):
A night vision device’s electronic function reduces the voltage sent to the photo cathode when the night
vision device is exposed to bright light sources such as room lights or car lights. BSP protects the image tube from
damage and enhances its life; however, it also has the disadvantage of lowering resolution when functioning. In
other words, this also protects you and your night vision optic from sudden bright lights, but when its functioning
it reduces the quality of the image.
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Generation (Image Intensifier Tubes):
The heart of any night vision system is an Image Intensifier Tube, sometimes referred to as the night vision
device’s Generation. Image intensifier tubes basically consist of a photo cathode which converts light images to
electron images (which, in turn can be amplified), and a micro channel plate (in the 2nd and 3rd generations), which
converts the flow of electrons back to a light image.
Generation 0 - Typically uses an S-1 photo cathode with peek responses in the blue-green region (with
photosensitivity of 60 mA/Im), electrostatic inversion, and electron acceleration to achieve gain. Consequently,
Gen 0 tubes are characterized by the presence of geometric distortion and need for active infrared illumination.
Generation I - Typically uses an S-20 photo cathode (with photosensitivity of 180 - 200 mA/Im), electrostatic
inversion, and electron acceleration to achieve gain. Consequently, Gen I was the first passive image intensifier.
Gen I is characterized by geometric distortion, weak performance at low light levels, and blooming. Expected
lifespan is 1500 hours.
Generation II - Usually an S-25 (extended red) photo cathode with photosensitivity of 240 + mA/Im and a micro
channel plate to achieve gain. Gen 2 tubes can be found with either electrostatic or fiber-optic inversion. Gen II
tubes provide satisfactory performance at low light levels and exhibit low distortion. Expected lifespan is 2500
hours.
Generation III - Uses gallium-arsenide for the photo cathode and micro channel plate for gain. The micro channel
plate is also coated with an ion barrier film to increase tube life. The generation 3 tube produces more than 800
mA/Im in the 450 to 950 manometer (near infrared) region of the spectrum. Gen III provides very good to excellent
low-light -level performance, long tube life. Expected lifespan is 10,000 hours.
Most consumers feel that a night vision device wont last long based on the tube lifespan, but in reality, if a night
vision device is being operated for 100 hours per YEAR, then this is considered A LOT of usage. At 100 hours per
year a Generation 2 device would last for 25 years and a Generation 3 device would last 100 years.
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Micro channel Plate (MCP):
The MCP is a metal-coated glass disk that multiplies the electrons produced by the photo cathode. A Micro
channel Plate is found only in Gen II and Gen III systems. These devices normally have anywhere from 2 to 6 million
holes (or channels) in them. MCPs eliminate the distortion characteristic of Gen 0 and Gen I systems. The number of
holes in the MCP is a major factor in determining resolution.
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Photo Cathode:
The photo cathode consists of the input wavelengths of the intensifier that absorbs light energy and in turn
releases energy in the form of an electron image. The type of material used is a distinguishing characteristic of
the different night vision device generations of image intensifiers. In other words, this is the part that processes
the image electronically and makes the electronic image brighter.
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Durability:
There are night vision optics which are o-ring sealed and nitrogen-purged for total waterproof and fogproof
protection. Such models can even be put under water, but will remain dry on the inside. The interior lens surfaces
won't fog up due to rapid temperature or humidity changes. Rubber armor is another efficient way to provide
durability as well as some additional benefits for your night vision binoculars, night vision monoculars, night
vision goggles, night vision rifle scopes, and other night vision devices. For one, the comfortable gripping surface
makes these night vision devices easier to hold onto. Also, it muffles the sound of any non-rubber objects bumping
against it, which keeps it from spooking wildlife.
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Coating Types:
Coatings of the lens surface reduce the loss of light and minimize glare due to reflection. This results in a
brighter image that has higher contrast and less eye strain. There are four basic types of lens coating.
*Coated - one layer of coating on at least one lens surface
*Fully Coated - one layer of coating on all air-to-glass lens surfaces
*Multi-Coated - multiple layers of coating on at least one lens surface
*Fully Multi-Coated - multiple layers of coating on all air-to-glass lens surfaces
* Phase coating (aka Phase-corrected prism coating) and dielectric prism coating - effective techniques implemented recently (since 2005) for reducing reflections. Phase coated prisms improve the brightness and quality of their more basic anti-reflective (AR) coatings. Most of the time, phase corrected prisms work together with their already fully multi-coated lenses.
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