Understanding Fog Proof Binoculars: Nitrogen Purged Vs Argon Purged

Unfortunately, most of us at some point have owned a pair of troublesome low-quality bird watching binoculars that fogged up. Perhaps some of you are still using them.

Like you, I’ve also endured bad experiences with low-grade binoculars, most notably during my vacation to Costa Rica many years ago. Each time I left the air-conditioned cabin for bird watching from the warm and humid patio, my binoculars would fog up on the inside – and no amount of repeatedly wiping the outer lenses would help. I was forced to wait several minutes to a few hours for the optics to clear up. This was not a successful way to enjoy birding!

Subjecting your binoculars to quick changes of temperature with medium to high humidity levels can cause internal condensation which is caused by moisture getting inside your binoculars. This is the sign of an air leak. Condensation can also occur when trying to use binoculars while viewing from an air-conditioned car on a very hot day. Once the window goes down and the cooled binoculars come out, all bets for quality bird watching or viewing wildlife are off.

If conditions are warm and humid enough, it is even possible for mold to eventually grow between the optics – making your binoculars useless.

Fortunately for us the optics industry has gone high-tech since our childhood days and interior lens condensation can be a problem of the past. Today’s high-quality binoculars are nitrogen gas or argon gas purged. Tightly sealed binoculars that are gas purged will keep moisture from getting inside the barrels and between the optics.

What does this really mean and how does gas purging prevent the internal condensation of binoculars?

Oxygen is removed from the barrels and therefore from in between the optics during the manufacturing process and either nitrogen gas or argon gas is used in its place. These gases are stable (inert) and don’t easily react with other elements. This characteristic is what keeps condensation off of the internal optics.

Nitrogen purging – a lower costing gas to create, use and manipulate during the binocular manufacturing process which offers good fog proof protection.

Argon purging – a more expensive fog proofing method. Argon molecules are larger than nitrogen molecules and thus less likely to leak out beyond the O-ring seals after the binoculars experience a hard fall. Argon purging is one of the highest quality water proof and internal fog proof methods available.

High-quality Vortex fog proof binoculars are manufactured using the gas purging technique. Some of the nitrogen purged models are the Vanquish, Raptor and Crossfire II. The argon purged models offering superior fog proof and water proof performance include the Diamondback, Talon HD and the Viper HD binoculars.

For successful and enjoyable sports viewing and bird watching it is important to have the highest quality optics that your budget will allow. Focusing your eyes on birds is what your bird watching endeavors are all about. Don’t take a chance with low-quality binoculars.

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