Values for Apparent Field of View
With the conventional method used previously, the apparent field of view was calculated by multiplying the real field of view by the binocular magnification. After revision, Nikon's figures are now based on the ISO 14132-1:2002 standard, and obtained by the following formula:
tan ω' = Γ x tan ω
Apparent field of view:2ω'
Real field of view:2ω
For example, the apparent field of view of 8x binoculars with an 8.8° real field of view is as follows:
- 2ω' = 2 x tan-1 (Γ x tan ω)
= 2 x tan-1 (8 x tan 4.4°)
Referring to the ISO 14132-2:2002 standard that was established at the same time as the abovementioned ISO 14132-1:2002, binoculars that provide an apparent field of view over 60° are considered wide-viewfield binoculars.