Bennett begins her lengthy article by explaining how binoculars work. There are two main styles: Galilean, which uses a concave lens at the eyepiece, and prism, which uses a convex lens at the eyepiece. The plus side to this convex eyepiece lens is that it allows for a wider field of vision. The downside to the use of this convex lens is that it inverts the image, so it needs to be re-inverted with mirrors before it reaches the eye. Within the prism category are two sub-categories:
Next Bennett's article provides a glossary of terms to inform users. First she explains magnification and objective lens size. These two numbers together are the numbers shown with a product name, such as Swarovski EL 10x32 or Nikon Monarch 3 8x42. By reading and understanding these numbers, a customer can get a very good idea of the size, the power, and the relative brightness of the pair they are considering. Next, Bennett defines other important terms such as exit pupil, field of view, close focus, diopter, eye relief, and interpupilary distance. She also explains the defect of chromatic aberration. This can sometimes occur when a lens refracts different wavelengths of light (colors) to different focal points. It makes the image look washed out and fuzzy. To compensate for chromatic aberration, many manufacturer's use extra-low dispersion glass (ED glass) which is constructed in a way that focuses different wavelengths to the same point. This results in a clear and color correct image. This type of glass is expensive and is usually found only on high end models. Both of the highest scoring products in Bennet's comparison review use ED glass, and both of these pairs won awards for their crisp and colorful images.
Lastly, Bennett walks readers through possible uses for binoculars and explains which types function best for different purposes. She notes the features to look for and then recommends the models she tested that fit into these categories. Popular uses for magnifiers are bird watching, hunting and wildlife viewing, marine trips, hiking and backpacking, star gazing and astronomy, and concert viewing. Bennett notes that some uses require certain features to function well, and she lists what those considerations are. For instance, a large objective lens is necessary for star gazing, which happens at night in the dark, since the larger the lens the more light can enter.
This Buying Guide has been published in tandem with a hands-on review of thirteen top models. This full review compares each model against one another and includes a write-up of each pair. Reference OutdoorGearLab's site for more information on what makes the best pair and which models took home awards.
OutdoorGearLab, LLC is based in Cheyenne, Wyoming, and is a free resource dedicated to helping consumers make informed purchasing decisions about outdoor gear when shopping online. The site, www.outdoorgearlab.com, contains comparison reviews of outdoor apparel and equipment, and complimentary buying advice guides for each category. The test team performs tests of gear, comparing products against one another in real world applications, and publishes their findings in written essays. Each product is scored across a range of weighted metrics, ranked against its competitors, and awards are given to the deserving models. Readers can then find the best possible product with minimal time invested in personal research. These reviews will inform anyone who participates in activities such as backpacking, hiking, camping, hunting, bird watching, running, swimming, and cycling.