Binoculars.org

A binoculars field of view (FOV) is the distance seen from left to right when looking through the binoculars.  Magnification and field of view work opposite each other in binoculars.  The more you magnify, the smaller the viewing area around the subject, while lower magnifications yield larger fields of view.  Some applications are best suited for lower magnification with wider views of the surroundings.  Field of view is an important factor to consider when selecting a binocular.

Measuring a Binoculars Field of View

You can measure a binoculars field of view in two ways - linear feet at 1000 yards or angular degrees.  The more popular measurement is feet at 1000 yards and is attributed on nearly all binoculars.  To get a visual on how this works, I like to use the ’never ending fence scenario’ -

Let’s use a 8×42 binocular that measures 330 ft. @ 1000 YardsImagine you are standing in a field and 1000 yards away from you is a fence.  This fence is infinitely wide from left to right.  When you look through the binoculars at this fence, you will see 330 feet of that fence without moving the binoculars.  Obviously if you wanted to see more of the fence, you would simply pan from side to side.  Field of view is the measurement of the distance seen from left to right through the binoculars.

Another way to measure field of view is in angular degrees.  This same 8×42 binocular for example may measure 6.3 Degrees for its field of view.  One degree of angle is equal to 52.5 feet at 1000 yards.  You can easily convert Feet at 1000 Yards to Angular FOV by dividing.  In this case, 330 feet divided by 52.5 = 6.28  It is common to simply round to 6.3  You can also convert from Angular FOV to Linear FOV with multiplication.  6.3 x 52.5 = 330.75

Remember - when selecting a binocular, “more is better” is not the case with magnification.  The more you magnify, the less stable your images will be in your view and the smaller your field of view.  Most experts agree that binoculars with 8x or 10x magnification are the best choices for almost all uses.  Maybe that’s why you see so many 8x and 10x power binoculars?  What good is it to be so highly magnified that you can hardly view the image comfortably.