The diopter adjustment makes up for differences in clarity between your eyes.

Diopter Adjustment: The diopter is an adjustable ring that is usually located near the right eyecup.

Extend the eye cups if you aren’t wearing glasses and keep them collapsed if you are wearing glasses.

Eye Cups: The eye cups are located on the end of the binoculars you look through.

You’ll need to adjust focus when looking at objects at different distances. Rotating this ring brings objects into focus.

Focus Ring: The focus ring is located between the two barrels.

Here are some other parts of binoculars you should know. By having two tubes, instead of one, we increase the amount of area we are able to see, which is the main advantage of binoculars over monoculars. A set of prisms solves this issue by reversing the image. Binoculars are basically just two of those telescopes. Those two lenses are called the objective and ocular lens, more on those in the section, “What do numbers on binoculars mean?”But as you look through it, you’ll notice that the image you’re seeing is upside down. If you take two converging lenses and put them on either end of a tube you’ll have a crude telescope. The same lens shape is used for magnifying glasses. These lenses are called converging lenses because the light converges in the middle and this light bending characteristic causes objects to appear larger when you look through them. Binocular lenses are thicker in the middle and taper out to a thinner edge, which bends light toward the middle. Backyard Bird Lover Backyard Bird Lover Binocular Anatomyīinoculars have three main parts: the objective lens, prisms and the ocular lens. What do the numbers on binoculars mean? By the end of this article you’ll fully understand binocular specs and anatomy, so you can choose the best binoculars for you. These different models have numbers like 10×42 and 15×56.

If you’re in the market for a set of binoculars, you’ll notice there are many options, even for the same model. Binoculars with a field of view 390 feet at 1,000 yards or above are generally considered wide field.We may earn revenue from the products available on this page and participate in affiliate programs. A typical 8x42 binocular has a field of view around 340 feet at 1,000 yards or 6.5 angular degrees. There are a few positive viewing points regarding a wide field of view: It’s easier to aim and stay on a moving subject, therefore binoculars with a wide field are generally preferred by birdwatchers. Likewise, dividing the linear field of view by 52.5 will give you the angular measurement. Thus, if you know the angular field of view in degrees, multiplying that number by 52.5 will give you the linear field of view of feet at 1,000 yards. You can easily convert from one measurement to the other by knowing that one angular degree is equivalent to 52.5 feet. Optical Field of View is the actual distance across your viewing field (left to right) when looking through a binocular or spotting scope. It can be measured in two different ways: linear feet at 1,000 yards (also known as True Field of View) and angular degrees (or Apparent Field of View). This is why spotting scopes must always be mounted on a tripod higher magnification makes them impractical to hold in your hands. Most individuals are fine with 6x and 8x, fewer can hold a 10x steady, but binoculars over 12x should probably be mounted on a tripod. This can have a critical impact on your ability to discern detail. Sure, objects will appear larger (closer to you), but high magnification binoculars are generally less easy to hold steady. However, a binocular with higher magnification doesn’t necessarily translate to a better view. In everyday vernacular, adding power to something is generally deemed a desirable thing. It’s somewhat regrettable in optical jargon that “power” is synonymous with magnification.

Examples would be 15-45圆0 and 20-60x80, the two most popular spotting scope configurations. Zoom magnification is expressed as two numbers from lowest to highest power. However, nearly all spotting scopes (but only a minority of binoculars) have variable magnification, more commonly called zoom. These are considered fixed magnification because they have a single power. Magnification is the first number indicated in a binocular specification, e.g., 6x32, 8x42, and 10x50. Thus, an 8x42 binocular magnifies your view eight times. Magnification, or “power” as it’s sometimes referred to, is a number indicating how much larger an object appears when viewing it through the optic versus the naked eye. Whether you’re considering the purchase of a binocular or a spotting scope, you’ll want to know the optical device’s magnification.

Binocular numbers meaning