I bought a cheap pair of 8x binos at Wal-mart for dashboard use. They will ride around a lot and be used a little. Anyway, I used them this evening to check out a small herd of deer in a field at about 200-300 yards. It was a little dark, but it still didn't seem like they provided the 8x as advertised. My Nikon 10x50s give a much better image, of course, but more importantly, seem to provide a heck of a lot more magnification.
Basically, is there any way to 'prove' the power of a optics? Would comparing them to a riflescope set on 8x be a valid comparison?