John Asked:

I buying drugs online have a pair that says they are 8 x 21 and field 7 but i have no idea what that binocular ratings means?

Reply:

8 refers to the power of the binocular ratings. They bring objects 8 times closer. 21 refers to the diameter of the objective lens in mm. 7 refers to the field of view in degrees. It is common currently to express field of view in feet per 1000 yards. 7 degrees is about equal to 365 ft at 1000 yards more or less. That is about average.

 

Super Astronomical Zoom Binocular Telescope 15 180X100
Super Astronomical Zoom Binocular Telescope 15 180X100
Paypal   US $72.16
Zhumell Tacyon 25x100 Astronomical Binoculars with Aluminum Carrying Case
Zhumell Tacyon 25x100 Astronomical Binoculars with Aluminum Carrying Case
Paypal   US $225.00
Zhumell 20x80mm SuperGiant Astronomical Binoculars
Zhumell 20x80mm SuperGiant Astronomical Binoculars
Paypal   US $43.00