There are a boatload of binoculars on the market these days, and making sense of the myriad claims, hype and gobbledygook terminology that fills the manufacturers' literature can be a bear. However, understanding just a few key terms and concepts and what's behind some of the buzzwords will help you find the best glass for your money.

Take the time to learn binocular terminology; it can mean the difference between a wise purchase and a wasted one.

A conventional binocular description--10x42, let's say--includes the magnification and the objective lens diameter in millimeters. Most optics makers say magnification is not as important as clarity, resolution and lens quality, because magnification is irrelevant if the optics are so dim that you can't see through them. True enough, but the whole point of having binoculars is to make far away things look closer, and the more magnification, the closer objects appear.

So first choose a magnification that meets your needs, then shop for the best optical quality you can afford. The higher the magnification, the better quality optical glass you'll need because all optical systems get dimmer as magnification increases. The only way to offset this is with high-grade lenses and prisms that allow superior light transmission.

On the objective lens side, bigger is better. The larger opening not only lets in more light and brightens your image but it also supports higher magnifications. Twenty years ago 7x40 was about as high as you could go. Today, technical advances in lens quality make 10x40 binoculars indispensable field tools. And premium optics makers such as Leica, Zeiss, and Swarovski are even offering crystal-view 10x32 glasses.

Given equal magnification and objective lens size, the sharpness, brightness and resolution of the image you see through two different binoculars depends on the optical quality of the glass. In a nutshell: The higher the grade of glass, the more expensive it is.

Binocular housings contain two glass objects inside: lenses and prisms. Lenses are round, flat pieces of glass stacked at the eyepiece and the objective end. Prisms are funny-shaped glass chunks that bounce light around to give you usable magnification, focal length and a right-side-up image.

Beyond these preliminary definitions things get pretty technical pretty quick, and--unfortunately--some of it you need to know.

Consider prisms. There are two basic types: Porro prisms, which are offset and route light at 90-degree angles; and roof prisms, which are overlapped and route light at more acute angles and are lightweight and compact. Porro-prism binoculars have the classic "stepped" offset look; roof-prism binoculars are slim and sleek with a straight-tube.

There are two types of roof prisms: Pechan (smaller) and Abbe-Koenig (larger). Pechan prisms have a mirror-type surface that inherently loses 4 to 6 percent of available light, so they are used in ultra-compact designs not intended for low-light conditions. Larger Abbe-Koenig roof prisms are employed in mid- and full-size instruments where twilight viewing is a factor.