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A Beginner’s Guide to Choosing Binoculars

Today binoculars are not merely sight extending gadgets or just simply a staple for tourists. These little power machines have evolved to suit specific needs and specific interests. With binoculars being tailor-made for astronomical purposes, bird watching, hunting, observing marine life, and other outdoor pursuits, it becomes all the more important to identify and narrow down on individual requirements.

Once you are clear on what you need, the next step is knowing the basics, what they mean and a successful selection of the pair meant for you. To help you make the correct buying decision, let us take a look at the meaning of some of the specifications in detail.

Celestron Binoculars


Magnification & Field of View – The very first numerals you will come across while looking for a pair of binoculars will be in its model number, like for example 9×45. The first digit refers to the power of magnification. The lower the magnification the wider will be the field of view resulting in more accurate viewing of fast-moving objects. Higher magnification with comparatively narrower field of view, on the other hand, lets you view the finer details of a scene.

While the second digit indicates the aperture size or the diameter of the front lens, also known as the objective lens, in millimeters. It is the size of the lens that determines its light gathering ability. The bigger the diameter, the clearer will be the view. And unlike lower magnification, a large aperture size means a wide angle view. Having a clear foresight of the purpose of the binoculars before making the purchase is a must.

Relative Brightness Index (RBI) – The RBI is a measure of brightness and can be calculated by squaring off the exit pupil. An exit pupil is calculated by dividing the power or magnification with the diameter. The digit received as a result is then squared off to get the index. An RBI of 25 and above is ideal and even favorable for low light conditions. The larger the exit pupil the brighter will be the viewing experience. Also, note that the exit pupil should be in accordance with the human eye pupil. It should not be less than 2mm and not more than 7mm.

Shape – Binoculars come in two shapes: Porro Prism and Roof Prism. The porro prism is the classic binocular shape everyone is familiar with while the roof prism is an evolved and a much more recent form. Due to no fuss designing, the porro prism binoculars, with offset prisms, are able to provide brighter, and in depth view while being easy on the pocket. The roof prism binoculars, with overlapping prisms, are more durable, compact, stylish and cost a little more than their traditional counterparts.

Enjoy your outdoor experiences better with just the right pair of binoculars. Doing some research can save your time and money, giving you just what you want. We, at Ryda, house an extensive collection of binoculars by renowned brands such as Nikon, Pentax, Bushnell, Olympus and many more. One look at the inventory will make you want to own one.

Hope the information listed guides you to the perfect pair of binoculars for you. What all you look for while buying one? Let us know in the comments below.

Happy Watching!

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One thought on “A Beginner’s Guide to Choosing Binoculars”

  1. I am amateur bird watchers and have been using a Nikon PROSTAFF 10×42 Binoculars that is old but fairly sufficient. I have researched for the right binocular and found what I need. The clarity is amazing and the ability of this binocular to allow you to view your objects at the low light of sunrise and sunset is fantastic. I am absolutely thrilled!

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