December 9, 2010

Binoculars (III/V) – diameter

There are four important numbers associated with any pair of binoculars: magnification, diameter, field of view, and price.


The second number “50” written on a pair of binoculars is the diameter of the objective lens. This number is more physics than practicality but in a nut shell the larger the diameter the more light enters the binocular producing a crisper, brighter image. For a more in depth description click here. Most bird watching binoculars run 30-50mm. The downside of a larger diameter is heavier, often more expensive binoculars.


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