December 10, 2010

Binoculars (IV/V) – field of view

There are four important numbers associated with a pair of binocular that you will need to know: magnification, diameter, field of view, and price.

The field of view is a number (not always written on the binocular) that is the width across that you can see at 1000 yards distance. This is best conceptualized by imagining that you are looking at a fence that runs right to left and is 1000 yards away. With a FOV of 200 feet you can see fewer fence posts than with a FOV of 400 feet. FOV is important for bird watchers when trying to find a tiny duck in the ocean or follow a darting warbler in the tree top. It is easier to locate small or fast moving birds through a larger sized field of view. You will sometimes have to look at the fine print to determine a specific pair of binoculars FOV but a good rule of thumb is about 350’ at 1000 yards. You will also find that binoculars with lower magnification may have a larger a FOV and be easier for the beginner bird watcher.


For example view this scene through three different FOVs.
Field of View

  





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is an educator, bird watcher, and writer fascinated by the intersections of place, people, nature, and culture. He works for Mass Audubon and lives in the heart of Massachusetts. For questions or comments please contact: alexanderjosephdunn@gmail.com

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