Calculation Involved In Magnification And Aperture Of Binocular

Sitting on a beach and wondering about nature will definitely tempt a person to have a closer look at the sun and the boats that are far away. Binoculars are a great tool to enjoy the glimpse of the objects that are far away.

Though they are used to provide a great treat to the eyes, they are used by more professionals to aid them in their work. Astronomers, hunters, military people use it in their profession. Whatever may be the use, one must understand that purchasing the best binocular is important. I found some great binoculars here. Check it to enjoy purchasing the best.

It is important to take note of the specifications before purchasing them. Binoculars come with a specification like “a x b”. Where ‘ a’ represents magnification and ‘b’ represents aperture. These are mere numbers for most of the people who use it. But, it is important to understand how these numbers are derived.


  • Get to know the focal length of the binocular tube. Though this is not provided on the body of the binocular, it can be found on the manufacturer’s
  • In a similar manner, find out the focal length of the eyepiece.
  • You will have two numbers, now; divide the focal length of the binocular tube by that of the eyepiece. The value that is obtained by dividing them is the magnification value (a). This value defines how large the object will be when viewed through the binocular.


This is calculated by measuring the diameter of the objective lens (b).

Though these are the two important measurements, various other measurements are calculated based on these two values.

So, when you see a specification say, 12×50 on binocular, remember that the first number 12 is obtained by dividing the focal length of the binocular tube and that of the eyepiece. The second number 50 is the diameter of the objective lens.

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