Objective Lens

The objective lenses are at the front end of the binocular. The width of the objective lens relates to the second number in the binoculars description. e.g. a 10×42 binocular has a pair of objective lenses that each measure 42mm in diameter.

Larger objective lenses give better light transmission and allow for a brighter picture. A larger objective lens will allow the binoculars to be used in lower light conditions.