What do the numbers on binoculars mean?

The numbers on binoculars refer to their magnification power and the size of the objective lens. The first number (e.g., 8x) indicates the amount by which the binoculars magnify an image. In this case, the object will appear eight times closer than it would to the naked eye. A higher magnification number means a closer view but can also result in a narrower field of view. The second number (e.g., 42mm) signifies the diameter of the objective lens in millimeters. A larger objective lens allows more light to enter, resulting in brighter and clearer images, especially in low-light conditions. However, it also implies larger, heavier, and potentially less portable binoculars. Therefore, while choosing binoculars, one should consider the optimal balance between desired magnification and portability.