Field of view is the amount of area that can be viewed through binoculars. The amount of area is the total left-right footage seen by your eyes through the binoculars.
The binoculars field of view is normally stamped on the binoculars and is typically expressed as “360FT/1000YD”. Which is read as “The field of view for these binoculars is 360 feet wide at a distance of 1000 yards”.
This means if your target was centered 1000 yards away, you would be able to also view 180 feet of terrain on both the left and right side of that target. Or if you were just scanning the terrain, you would be able to observe 360 feet of coverage at any given moment.
Better quality binoculars tend to have a field of view between 315 and 390 feet at 1000 yards. Those are general guidelines, but will satisfy field of view requirements for birding, hunting, marine activities, and most spectator sports.
Linear and Angular Field Of View.
Both of these readings will result in the same measurement at your target distance of 1000 yards.
Linear field of view is most commonly used as it is expressed in feet and yards in a factual statement (330FT/1000YD). That expression can be quickly understood to mean that at 1000 yards your will see 330 feet of left-right terrain with the binoculars.
The angular field of view is expressed in degrees. As an example, a reading of 6.3 degrees means that the view from the binoculars will expand outward 6.3 degrees from each of your eyes.
Conversion to either linear or angular field of view is done with the factor of one degree being equal to 52.5 feet.
Angular degrees of 6.3 will convert to 330.75 feet (6.3 degrees X 52.5 = 330.75 feet).
Linear feet of 330.75 will convert to 6.3 degrees (330.75 feet / 52.5 = 6.3 degrees).
Magnification Versus Field Of View.
The magnification and the field of view are two binocular features that work in opposition to each other. In general, the more powerful binoculars (12 X 50) will have a smaller field of view (290FT/1000YD), while less powerful binoculars (8 X 42) will typically have a wider field of view (380FT/1000YD).
Most binoculars tend to fall into either the 8X or the 10X magnification ranges because at higher power binoculars often have poorer quality images and smaller fields of view.
The most common linear/angular fields of view binoculars are between 6.0 degrees/315 feet and 7.5 degrees/390 feet. Wide angle binoculars begin at 8.0 degrees/420 feet and work upward.