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There are two main numbers on all binoculars. The first number indicates the power or the magnification vs. the naked eye. The second number refers to the diameter of the objective or front lens in millimeters. The higher the first number, the higher power or more magnification. The larger the second number, the larger the opening for light to enter the binocular.
There are three measurements of quality in binoculars: lens and prism optical quality, mechanical and alignment quality and design quality. The best quality binoculars, such as PENTAX, use photographic quality lenses, multi-layer optical coatings, and high-density BaK-4 prisms. This insures the brightest, highest contrast and sharpest image possible. PENTAX uses the strongest, lightest materials; oversized bearing surfaces on moving parts; and the highest precision manufacturing to achieve superlative mechanical quality and alignment. PENTAX makes over thirty-one different models of binoculars and monoculars in seven different designs!
Binocular designs fall in two broad categories; roof prism and porro prism. Historically, porro prisms were the first types of binoculars, but they had some design limitations. Roof prisms were developed because the new design made it possible to build smaller and lighter binoculars. Here is a look at the advantages and disadvantages of porro prism vs. roof prism design.
Porro prism Advantages:
Less expensive, excellent optical quality and in most cases, they can gather more light.
Disadvantages:
Less compact, more awkward to hold for long periods, generally less rugged than roof prisms.
Roof prism Advantages:
More compact than comparable porro prism model and usually easier to hold for long periods. Roof prism binoculars are manufactured to closer optical and mechanical tolerances making them more rugged than comparable quality porro prism binoculars. Another important feature of the roof prism design is the ability to make this binocular weather-resistant and waterproof.
Disadvantages:
Can be slightly higher priced.
PENTAX rates their products by the "Japanese Industrial Standard" (JIS). Ratings are established through tests to prove protection against the ingress of water. While we call instruments "waterproof" and "weather-resistant," it is important to understand that there are degrees to which an instrument is "waterproof." The classifications range from one to eight. Eight is the highest level of water protection. Here is a breakdown of the classification system and where PENTAX binoculars fall:
UCF WR Class 4:Splash-proof from any direction
DCF HR Class 5: Jet-proof from any direction
DCF WP Class 6: Watertight submersible to 1 meter
PIF Class 7: Submersible to 1/2 atmosphere (16.5 feet) Class 8: Products designed specifically for underwater use such as an underwater camera. To make a binocular weather-resistant, special "O" rings are used in constructing the binocular to keep water from entering the instrument. To make a binocular waterproof, "O" rings are used in a special internal design that allows the binocular to be totally sealed. The binocular is then filled with nitrogen which makes it waterproof and submergible. Weather-resistant and waterproof binoculars are also "fogproof."
What bino is best for me?"
Several companies market inexpensive binoculars that are "focus free." That is, they have no focus adjustment, and the makers claim that they are always in focus. In truth, they are hardly ever in focus. The focus on these models is permanently locked at just short of infinity. To view anything that is not at exactly that distance, the viewer's eyes must shift focus. This constant focusing causes eye strain and often makes it impossible to get a clear view. This design also is useless for close-in viewing (frequently done by birders) at distances shorter than 40 or 50 feet. PENTAX does not make a focus free binocular (we prefer to have our instruments focus exactly on the object being viewed), but the focus on all PCF III models can be locked for convenience. We consider focus free a negative feature, as it is not an advantage for the binocular user. It has no place in high quality binoculars. |
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