BINOCULARS
Binoculars are essential boating and camping equipment. On the
water you need them to identify aids to navigation (bouys), other boats,
obstructions in the water, lighthouses, towers, etc. Camping and
hiking you need them to identify landmarks, flora and fauna. Binoculars
are indispensable for bird watchers; without them you would not be able
to see a tiny bird some distance away or identify it. There are two
types of binoculars, roof and porro prism types. The lens in roof
binoculars are in line whereas they are offset in porro prism
binoculars; generally porro prism binoculars are optically superior to
roof binoculars.
The quality of the lens and their coating (s?) is very important.
BaK-4 prisms are made of the best optical glass. The glass needs to be
coated to reduce reduce reflections. All of the binoculars on
www.mountains-and-seas.com use BaK-4 prisms and have multi-coated lenses
and all but the Pentax 7X50 marine binoculars with a built-in compass
are porro prism type.
Numbers are associated with binoculars, e.g., 7X50, 8X42, etc.
The first number indicates the degree of magnification, e.g., in 7X50
binoculars the object appears seven times closer than it does to the
naked eye. The second refers to the diameter of the forward looking
lens in millimeters, in this example 50 millimeters. Increasing the
magnification would seem desirable; however, higher magnification limits
the field of vision and tends to make it dimmer. Also it is hard to
hold binoculars with higher magnification steady enough to avoid a
blurred image. A 7X50 binocular is ideal on the water and is standard
in navies & militaries.
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