The listed magnification power (the first number in the formula) indicates how many times larger an image appears through the ocular lenses than it does with an unaided eye. In the case of the formula 7×50, a pair of binoculars with this magnification would produce an image that is 7 times larger than what you would see with your eyes alone.

A pair of 7×50 binoculars will magnify 7 times and employ objective lenses of 50mm diameter. These binoculars will provide an exit pupil of 2.5mm (objective lens divided by magnification). An exit pupil of this size provides plenty of daylight power with decent cloudy or late-afternoon visibility.