10x20 is the same as saying 2x magnification? Frequently when we go buy Binoculars or see some on Amazon.com, it says 10x20 or 7x50. Does 10x20 not mean 10x magnification but 2x? That number comes from 20 / 10. So 7x50 is 7x (by 50 / 7)... and 10x20 is actually 10x20mm? Are those the focal length of the eyepiece versus the object lens, so whatever they are, a division can give the real magnification power?
By the way, is the 10x magnification actually 3.3x width and 3.3x height? (making it 10x for area of an object) That's because if I see a house far away being a height of say, 1cm, then I use a binoculars that says 10x magnification and the house doesn't look like 10cm tall... at most it looks like 2cm or 3cm tall. So that's why I really wonder how the "10x" comes from.