Hi publin,
Almost right.
Except that 4.99 x 16 is about 79.8 degrees not 7.98 degrees AFOV apparent field of view simple calculation. True AFOV less.
The 4.99 degrees or more accurately 5.0 degrees is the claimed actual field.
Much better not to use a calculator and do the sum in ones head, or long hand on the back of an envelope
If the information is correct, then Jason was a U.S. firm that coined the phrase 'Autofocus Binocular'. Whether
Jason, Steiner or someone else first came up with this untruth (lie) I don't know.
Jason may have been bought by Bushnell.
Jason also seemed to have pushed toggle focus binoculars. All the toggle focus binoculars I have used are poor. Too fast and imprecise focus, and mechanically poor.
So it doesn't surprise me if the field marked is deliberately inflated.
But if I have Jason's history wrong, I apologise, as I have no direct knowledge of the firm.
The binocular could even be Japanese or maybe Korean, Hong Kong, Macau.
Probably O.K. but cheap.
And the markings deliberately wrong.
The dubious makers will put what ever one wants on the binocular.
The internet is awash with fakes, scams and shams.
B.