what do numbers on binoculars mean
All binoculars will have two numbers to designate them, such as 10x50. This means a binocular with 10 times magnification and 50mm objective lenses (the big ones!). Common sizes are 8x42, 10x50, 20x60, 15x70, etc. Optical glass is generally BAK4 or BAK7 standard, BAK4 is denser and gives superior vision.