The objective lens diameter specifies how much light can enter the optics. This makes it a key factor in an instrument’s performance, for example, in twilight. The bigger the objective lens diameter, the more light the objective lens can capture. The darker the surroundings, the larger the objective lens diameter needs to be. Check the precise product name as the number after the ‘x’ specifies the objective lens diameter in millimeters. For example, a device with the suffix 10x42 has an objective lens with a diameter of 42 mm.
The large field of view and optics providing edge-to-edge sharpness make the EL 8.5x42 binoculars versatile to use. The 4.9-mm exit pupils also produce bright images in poor light conditions.