Posts belonging to Category 'Technical'

What do binocular numbers mean?

I asked this question in a hurry. We were at the airport waiting to fly to Peru, our once in a lifetime trip was planned to the last detail. I had forgotten to sort out binoculars for our stay on an oxbow lake in the Amazon. With so much variety I had to understand what […]


How To Use Binoculars With Glasses: Eye-relief & Eye-cups Explained

A question I often get asked is: How to use binoculars with glasses?, or If I wear eyeglasses, do I need to buy special binoculars? Unfortunately the answer is not just clear cut and I will try and explain as best I can: It often depends on why you wear glasses: If you wear glasses […]


Ocular Lens Size in Binoculars

The size of the ocular lenses on binoculars is something that is almost never considered when buyers decide as to which is best. However apart from measuring them yourselves there is actually very little way of knowing what size oculars a particular model has. This is because very few brands actually publish this information and […]


Binoculars 101: Magnification, Stability, Field of View & Brightness

How a Binoculars Magnification affects your Viewing Experience In this article I’m going to discuss magnification and in particular how a binoculars power (magnification) impacts your experience whilst using it. Please note: For the purpose of this document, I’ll be using the terms power and magnification interchangeably. Size of the Binocular When considering a binoculars […]


How Different Configurations Affect a Binocular

10x42, 8x42, 8x32, 10x26… What is right for me? I often get asked questions in relation to the different configurations of a binocular and which one is the best for a particular use or uses. So I thought I would put this document together that goes through the major binocular configurations and explains each of […]


Extra Low Dispersion Glass (ED Glass)

In recent years we have seen a huge increase in the amount of binoculars that use ED Glass (Extra Low Dispersion Glass) in their lenses. What used to be found only on a few of the very top end “super” binoculars, is now quite common and is used on a whole range of binoculars, even […]


Phase Correction in Binoculars

Phase Correction on Binoculars After the light travels through the objective lenses on a roof prism binocular, it then reflects off the surfaces of the prism. These multiple internal reflections on the prism and because of a phenomenon known as Brewster’s or the polarization angle, cause the light to become partly polarized and the light […]


Anti-Reflection Lens Coatings on Binoculars

In binoculars, anti-reflection coatings are mainly designed to assist with light transmission thus helping to produce a brighter image with better contrast. These days almost all good quality binoculars some sort of these coatings applied to at least some of the air to glass surfaces of their lenses. These anti-reflection coatings are often made up […]


Apochromatic (APO) Lenses in Binoculars

Recently I have seen as well as reviewed and tested more and more top end binoculars that use Apochromatic lenses (APO) and whilst some manufacturers mention that their products have an APO optical system, very few (if any) go on to explain exactly what it is and what it does. So with this in mind […]