A Binocular Buyers Quick Guide

August 17th, 2008 by admin

-->

What Do You Need To Know about binoculars?

Binoculars are very popular optical instruments with a multitude of potential applications. Choosing the right pair to suit your requirements is essential. With so many manufacturers and different types of binoculars, the choice can be bewildering. They range from opera glasses to astronomical instruments with many options in between.

There are binoculars suitable for use at sea, for watching sports, hunting, Bird Watching Binoculars, you name it. They come in waterproof, compact, night vision and as well as the traditional optical models, there are the increasingly popular digital and camera binoculars.

Technical points

You need to understand some terminology associated with binoculars. This will be helpful in choosing the right pair for your needs. In ads for binoculars, you will see two figures separated by x, for example, 10×42. What does this mean for you?

The first figure, in this case 10, is the degree of magnification or how large objects will look compared to their appearance with the naked eye. The second figure tells us that the lenses are 42mm in diameter. The larger this is, the more light is allowed into the binoculars, which effects the potential quality of the images produced.

The field of view is another important factor, being the amount of territory that you see when you are look through the binocular. This is determined two things, the magnification and the eyepiece design.

The exit pupil in a binocular is the actual width of the beam of light that leaves the eyepieces and is measured in millimetres. To see an exit pupil all you need to do is hold the binocular at arms length and you will see a circle of light in each eyepiece. This circle is the exit pupil, and to calculate the exact size of the exit pupil, you simply divide the second binocular number by the first binocular number.

In our example from above, 10×42 gives an exit pupil of 4.2mm. This is important for two reasons. First, a larger exit pupil makes it easier to keep centred on the eye. This is an advantage if for instance, you are on the moving deck of a boat, or if you are following fast moving action at a sports event. Secondly, the size of the exit pupil gives us some indication of how well the binoculars will perform in low light conditions. There is a mathematical formula for this but we don’t want to go there.

When we move into the realm of digital and camera binoculars, other factors come into play such as image stabilization. That is beyond the scope of this article but there is more information available on this site and links to other resources.

The Choice is Yours

Buying binoculars, especially for the first time can be daunting. I hope this has been of some help in deciding which factors are important to you. There is enough choice out there to enable anybody to find something to suit their needs and budget.