While there are many models of binoculars on the market, not all are equal. In addition to the differences in magnification and the diameter of the outer lens, which affects the overall brightness of the image, the quality of the glass used to build the binoculars will greatly affect the image clarity. Generally, companies that make camera lenses also build top-notch binoculars.
Looking through a pair of Leica binoculars, even their entry level 10x25 model ($749, 2010 prices), is the equivalent of feeling like your eyes have moved to the image, instead of feeling like you are viewing the image through a lens. Leica's top-end binoculars, like the 10x42 Ultravid ($2199, 2010 prices), are an investment that yields stunning optical clarity, ensuring no eye fatigue even while looking through the binoculars for extended periods. Leica is a German company that is best known for rangefinder cameras, but they introduced their first pair of binoculars in 1907.
Renowned for its quality, Carl Zeiss glass is the choice of many professional photographers. Founded in Germany in 1846, Zeiss has a long history in developing top-end optics for medical and industrial uses, in addition to photography and sport optics. Zeiss's Advanced Optics System improves optical performance while reducing weight by making the lenses thinner in the center. Zeiss's Victory FL line uses fluoride-containing glasses to maximize performance in their 10x42 ($2299, 2010 prices). The Victory RF system improves on the FL series by using a laser rangefinder system, which is why the 10x45 ($2999, 2010 prices), got an Editors Choice Award from Outdoor Life.
Swarovski is an Austrian company that rivals the German powerhouses, Zeiss and Leica, for optical quality. While Daniel Swarovski started as a maker of stunning crystal stones, Wilhelm Swarovski, the son of Daniel founded Swarovski Optik in 1949 because of his passion for astronomy. The top-end EL series incorporates fluoride high-definition field-flattener lenses to minimize chromatic aberrations and create a virtually flat image with no edge distortion. The 8.5x42 EL ($2339, 2010 prices), is a popular choice among birders and hunters for its clarity and function.