Swarovski Optik BTX eyepiece module

The objective lens diameter specifies the amount of light that can enter the optical device. This makes it a key factor in an instrument's performance, for example, at dusk. The larger the objective lens diameter, the more light it can capture. The darker the environment, the larger the objective lens diameter you'll need. Check the exact 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.

Variable magnification allows you to flexibly adjust the magnification within a specific range. Unlike fixed magnification, it allows you to zoom from the lowest to the highest value. However, as the magnification increases, the field of view, i.e., the section of the image, decreases. Check the exact product name, as the number preceding the "x" indicates the magnification. For example, 30-70x95 is a device with variable magnification, from 30x to 70x.