SPOTTING SCOPE
An optical instrument used to view distant objects primarily
on land.
Coated Optics
Coatings on lens surfaces reduce light loss and glare due to
reflection, resulting in a brighter, higher-contrast image
with reduced eyestrain. Bushnell spotting scopes are coated
with a microscopic film of magnesium fluoride. More coating
leads to better light transmission.
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TYPES OF COATING |
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Coated - A single layer
on at least one lens.
Fully-Coated - A single
layer on all air-to-glass surfaces.
Multi-Coated - Multiple
layers on at least one lens and all surfaces are coated at
least once.
Fully Multi-Coated -
Multiple layers on all
air-to-glass surfaces. |
Exit Pupil
The exit pupil refers to the size of the column of light that
exits a spotting scope. The larger the exit pupil, the
brighter the image. To determine the size, divide the
objective lens diameter by the power (a 15x45 model has an
exit pupil, or useable light, of 3mm).
Eye Relief
The distance a spotting scope can be held away from the eye
and still present the full field of view. Extended or long eye
relief reduces eyestrain and is ideal for eyeglass wearers.
Field of View (F.O.V.)
Field of view is the side-to-side measurement of the circular
viewing field or subject area. It is defined by the width in
feet or meters of the area visible at 1000 yards or meters. A
wide field of view is better for following fast-moving action
or scanning for wildlife. Generally, the higher the
magnification, the narrower the field of view.
FOLDED LIGHT PATH
A combination optical configuration using lenses and mirrors
to create a total scope length much shorter than the total
focal length of the system. This provides a compact design
yielding long focal length performance.
Magnification (Power)
Spotting scopes are often referred to by two numbers separated
by an "x". For example: 15-45x60. The first number is the
power or magnification of the spotting scope. With a 15-45x60
variable power spotting scope, the object being viewed appears
to be 15-45 times closer than you would see it with the
unaided eye.
Multi-position eyepiece
Bushnell's exclusive multi-position eye-piece is available on
our 78-7350 and 78-7360 Spacemaster® models. This
revolutionary eyepiece features an infinite number of viewing
positions between straight-thru and 90 degrees-providing
flexibility for viewing comfortably in any situation.
Near or Close Focus
The closest you can be to an object and maintain visual
clarity.
Objective Lens Size
The second number in the formula: (15-45x60) is the diameter
of the objective or front lens. The larger the objective lens,
the more light that enters the spotting scope, and the
brighter the image.
Prism Glass
Most optical prisms are made from borosilicate (BK-7) glass or
barium crown (BAK-4) glass. BAK-4 is higher quality glass
yielding brighter images and high edge sharpness.
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PRISM SYSTEMS |
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The
prism system turns what would be an upside-down image
right-side up.
Roof Prism System - The
prisms overlap closely, allowing the objective lenses to
line up directly with the eyepiece. The result is a slim,
streamlined shape in which the lenses and prisms that
magnify and correct the image are in a straight line.
Porro Prism System - The
objective or front lens is offset from the eyepiece. Porro
prisms provide greater depth perception and generally
offer a wider field of view. |
RAINGUARD®
Our exclusive, patent-pending, hydrophobic (water-repellent)
coating on which condensation from rain, fog or snow forms in
much smaller droplets than on standard coatings. Smaller
droplets scatter less light which results in increased light
transmission and a clearer image.
Resolution
Resolution, or definition, is the ability of a spotting scope
to distinguish fine detail and retain clarity.
 Waterproof/Fogproof
Some scopes are sealed with o-rings and are nitrogen-purged
for waterproof and fogproof protection. These models are able
to withstand complete immersion and remain dry inside. |
