What is the exit pupil in binoculars?

The exit pupil is the diameter of the light beam that exits the eyepiece. A larger exit pupil allows more light to reach your eyes, resulting in brighter images, especially in low-light conditions like dawn or dusk.For example, saxon 8x42 precision binoculars have an exit pupil of 5.25mm (42 ÷ 8 = 5.25), influencing image brightness, especially in low-light conditions.