Unfortunately, most of us have at some point had a pair of poor quality troublesome birding binoculars that got fogged up. Maybe some of you are still using them.
Like you, I have also endured bad experiences with poor quality binoculars, especially during my vacations in Costa Rica many years ago. Every time I stepped out of the air-conditioned cabin to birdwatch from the hot, humid patio, my binoculars would fog up inside, and it wouldn’t help much to repeatedly clean the outer lenses. I was forced to wait several minutes to a few hours for the optics to clear. This was not a successful way to enjoy bird watching!
Subjecting your binoculars to rapid changes in temperature with medium to high humidity levels can cause internal condensation that is caused by moisture entering 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 is rolled down and the chilled binoculars come out, all bets on quality bird watching or wildlife viewing are off.
If conditions are warm and humid enough, it is even possible that mold will eventually grow between the optics, rendering your binoculars useless.
Fortunately for us, the optics industry has gone high-tech since our childhood days and condensation on interior lenses can be a problem of the past. Today’s high-quality binoculars are purged with nitrogen gas or argon gas. Hermetically sealed binoculars that are gas purged will prevent moisture from entering the barrels and between the optics.
What does this actually mean and how does the gas purge prevent internal condensation from the binoculars?
Oxygen is removed from the barrels and therefore from between the optics during the manufacturing process and nitrogen gas or argon gas is used instead. These gases are stable (inert) and do not react easily with other elements. This feature is what keeps condensation out of the internal optics.
Nitrogen Purge – A lower cost gas to create, use, and manipulate during the binocular manufacturing process that offers good fog-proof protection.
Argon Purge – A more expensive mist protection method. Argon molecules are larger than nitrogen molecules and are therefore less likely to leak past the O-rings after the binoculars experience a sharp drop. Argon purging is one of the highest quality internal fog and water test methods available.
High-quality Vortex fog-proof binoculars are manufactured using the gas purge technique. Some of the nitrogen purged models are Vanquish, Raptor, and Crossfire II. Argon purged models that offer superior fog and waterproof performance include the Diamondback, Talon HD, and Viper HD binoculars.
For successful and enjoyable sports viewing and birding, it is important to have the highest quality optics that your budget allows. Focusing your eyes on the birds is what your birding efforts are all about. Don’t take chances with low-quality binoculars.