What Do the Numbers Mean on Binoculars?

When you need to bring a distant object or person up close for identification or simply to have a better look, binoculars are the way to go. With a price range from about $10 to well over $1,000, binoculars come in various sizes and magnification powers. But what do those numbers on binoculars mean? It's actually quite simple and once you understand, you'll be in better shape to make a wise purchase.

First Number

When a binocular notes it is a 7x25, 8x40 or 10x50, the "7," "8" or "10" refers to the magnification power.

Magnification

The first number, the magnification, tells how many times larger the image will be seen as.

Shake

The higher the magnification power, the larger the image but the smaller the field of view. Also, it is harder to hold a binocular steady at higher magnification.

Second Number

For binoculars that are 7x25, 8x40 or 10x50, the "25," "40" or "50" is the measurement in millimeters of the objective lens.

Size

Because it is the measurement of the objective lens glass, the second number also determines the size of the binoculars.

Light Gathering

The larger the objective lens, indicated by a larger second number, also allows more light to be gathered and may result in a brighter image.