A few thoughts and hints to help you choose a binocular most appropriate for your purpose. Binoculars are for the most part interchangeable for various uses.
However it makes no sense for a hunter who has his binoculars hanging from his neck
all day to buy more weight than needed. The same could be said for tourists and hikers.
On the other hand boaters could use a larger and heavier binocular such as 10x50 because the boat does the carrying. Also for the boater a waterproof binocular is a good
consideration. Also if you go to a 10 power binocular a little extra weight helps steady
the instrument. It does not take much movement at 10 power to loose the object of vision.
Birders for the most part prefer 8x40-42 or 10x40 without much weight. Here a low light capability would be important because birds are most active in early and late hours when light conditions are less than ideal.
For viewing of sporting events your main consideration is field of vision, that is the width in feet of your view at 1000 yards.
Again, most binoculars could be used in almost all situations, some are just better suited
to certain tasks. If you want your binoculars to fill more than one need a midsize in 8x40
should cover most uses.
Binoculars is one area where the axiom you get what you pay for is consistently true. Premium binoculars are a combination of features and quality built in by the manufacturer. Keep in mind all binoculars are not the same. A set of 8x40 could vary in price from $25.00 to $1500.00. Quality is the difference.
Now a few words about binocular terms and numbers. Technical information is not always the best indicator of binoculars use but is helpful in selecting them. Lets start with a pair of binoculars with the numbers 8x40x135. The 8 is the magnification factor meaning the objects is 8 times the size compared to the naked eye. The 40 is the diameter of the objective lens (the large one on the front). The 135 would be the width in feet of the scene viewed at 1000 yards.
TERMS:
Alignment: The precise positioning of the machinery and optic by the manufacturer.
Dealignment: The destruction of precise positioning usually caused by jarring i.e. dropping.
Coatings: These are thin layers of substances baked onto the polished optics to reduce
reflections and increase light transmission.
Diooptic correction: The mechanical adjustment of the instrument to different
individual users sight.
Individual Ocular Adjustment: Focuses each eyepiece separately
Interior Focusing: Lenses dont move, found only in quality binoculars
Resolution: the ability of instrument to distinguish detail at a distance.
Eye piece for eyeglass wearers: Generally a fold down rubber stand off to maintain
correct eye and ocular lens separation. Eye glass wearers simply fold them down to maintain this relationship.
Field of vision: The width of view at 1000 yards
Occular: The lens closest to the eye
Exit pupil: A function of the objective lens in MM divided by the magnification factor
Low light or twilight performance: A desirable feature in most cases, but not an over
all indicator of quality.
Wide Angle Binoculars: Binoculars are designated wide angle when the field of view
is at least 60 degrees. (one degree = 52.5 feet at 1000 yards).
