Let's do an easy one, today.

Some people believe that rubber armoring makes a binocular waterproof or that a binocular needs to be rubber armored to be waterproof. Myth or fact?

Let's look at a couple of binoculars.

First,the Leica Ultravid BL 8x20 binocular. The Leica BL series of binocular is a leatherette covered binocular, not a rubber armored binocular. "Leatherette" is the old fashioned, textured coating that used to be the standard covering on binoculars before rubber armoring became popular. A quick check of the specs shows that the Leica BL is, in fact, waterproof, just like the rubber armored version, Leica Ultravid 8x20 BR binocular.

Let's look at another classic,the Nikon Astro Luxe 18x70 binocular. Like the Ultravid BL, the Nikon is also leatherette covered, not armored and, like the Ultravid BL, it is also fully waterproof.

Okay, myth busted. What's going on?

To make a binocular waterproof it must be sealed internally with O-rings, then all the air removed (air contains water vapor). This is done by forcing nitrogen gas into the binocular (nitrogen gas contains no water vapor) to replace all the air. This process is called nitrogen purging. Simply covering the binocular with rubber doesn't get the job done.

So why armor a binocular? Rubber armoring serves several purposes. It makes a binocular easier to grip (depending on the texture of the armoring)and it also makes a binocular more comfortable to hold in cold weather. Rubber armoring, as you might expect, also protects the binocular from scratches and dings. Lastly, rubber armoring "quiets" a binocular; a rubber armored binocular will not make as much noise when it bangs against another object such as a camera or rifle. This is important for applications requiring an observer to closely approach wildlife.