What does it all mean? Below are examples of typical binoculars purchased based on use. If the terminology is not familiar use the binoculars glossary for clarification. If you have any additional questions please contact us.
|Marine||Any Waterproof Model with a large objective diameter, and Rubber Armor, 7X50, 7X42, 8X42 & 10X42|
|Concerts/Sports||5X25 & 8X25 Xtra-Wide Angle, All 7X35, 10X50 & 12X50 for stadiumsTheater 4X30, 7X18 & 7X21 Compacts, Any Zoom or Wide Angle model|
|Astronomy||Any 10X42, 10X50 & 12X50 with Tripod adapter|
|Hunting||All Rubber Armored, Waterproof and Fog proof Models, 7X To10X Models. For general hunting, 12X or16X for distant Game/Varmints, Compacts fit in a pocket for hunters on the move.|
|Birding/Marine||8X42 is the Standard, For details in smaller species at a distance, Compacts with a 30mm or greater objective, any binocular with Long Eye Relief and good Close Focusing Ability.|
Binoculars Glossary (courtesy Swarovski binoculars)
|A shock absorbing cover on the optical instrument made of a rubber or polyurethane shell|
|Measuzres how bright an image appears through binoculars or spotting scope. The more light that is let in through the instrument, the brighter the image appears. Brightness is determined by three elements: the power, size of objective lens and coatings. Fully multi-coated optics can increase relative brightness by more than 50 percent.|
|Both binocular eyepieces are focused at the same time by a center wheel or lever. This is the best and fastest method.|
|Coatings on the optical
elements (lenses and prisms) of optical instruments help
to reduce light loss and glare from reflection and contrast.
There are various types of coatings offered by different
companies, including coatings that block ultraviolet light.
It is generally acknowledged that fully multi-coated is
the best. Here are some types you will encounter:
Coated Optics. Coating on one side of the objective lens system, one side of the ocular lens system, and the long side of the prism.
Fully Coated. Coating on both sides of the objective lens system, both sides of the ocular lens system, and the long side of the prism.
Fully Multicoated Fully coated optics on all air-to-air glass surfaces with one or more additional chemical coatings.
|Depth of Field|
|Refers to the distance seen near to far through a binocular or spotting scope. A generous depth of field assists when trying to locate close-at-hand subjects, such as a bird in a maze of branches. Generally, binoculars with lower magnifications offer greater depth of field, and a wider field of view than binoculars with higher magnification.|
|Eyesight adjustment collar found on the right or left eyepieces of binoculars, allows user to adjust for variances in vision between their right and left eyes.|
|Also known as the ocular, the lenses closest to your eyes. The eyepieces serve as the magnifying lenses and consist of multiple optical elements.|
|A function of optical design, this is the distance a binocular or scope can be held away from the eye and still present the full field of view. Long eye relief (16mm to 20mm) is especially useful for those who wear glasses. Some manufacturers also provide adjustable eyecups that accommodate both eyeglass and non-eyeglass wearers.|
|The exit pupil is the diameter of the beam of light that passes through the binocular into your eyes. Larger exit pupils are more advantageous in low light conditions. To calculate what the exit pupil of a binocular is, divide the objective diameter or lens size of the binocular by the magnification. Using this formula, a 7x42 binocular has an exit pupil of 6mm (42 divided by 7). Exit pupils larger than 7mm are of no benefit because the pupil of the human eye never gets larger than that.|
|Field of View|
|The field of view is the width of an area you can see at 1,000 yards. Most binoculars have the field of view indicated on them. You can measure field of view in degrees or feet. Each degree equals 52.5 feet of width at 1,000 yards. So, a binocular that indicates an eight-degree field of view has a 420-foot field of view at 1,000 yards (8 x 52.5 = 420).|
|Each eyepiece must be adjusted to bring an object into focus.|
|The closest you can be to an object while still maintaining visual clarity. Also called close focus.|
|The front lens of a binocular, or the farthest from your eye.|
|Objective Lens Size|
|Measured in millimeters, the diameter is always printed along with the magnification on a binocular. In a 10x42 binocular, the second number, 42, indicates that the objective lens' diameter is 42mm. The larger the number, the more light gathered and the brighter the image, an important feature in lower light conditions.|
|Focus is fixed by the manufacturer to the optimum point, usually 50 to 75 feet. This feature is not found in premium optics.|
|The amount of magnification. In a 10x42 binocular, the first number, 10, refers to the fact that you will be magnifying an object ten times closer than the naked eye.|
|The ability of a binocular or spotting scope to distinguish fine detail, probably as important as magnification.|
|Optical instruments that are sealed against dust, pollen and moisture. A very few superior binoculars and spotting scopes are waterproof / submersible - as opposed to water resistant, weather resistant and splash proof - and are able to withstand complete immersion and remain dry inside.|