Fog Proof and Waterproof Binoculars: What You Need to Know

In recent years, the market has seen binoculars of different sizes and shapes that offer unique features. Now the average outdoorsman can enjoy using decent binoculars without breaking the bank. One of such features you would often see on binoculars specifications is the waterproof and fog proof feature.

Today, let’s look more into these features and see what exactly they actually mean.

Waterproof Binoculars

` Waterproof simply means to prevent water from entering something. So, when binoculars are fully waterproof means they are completely sealed internally to prevent water from entering them. To accomplish this, a method called O-ring sealing is employed.

Fog Proof and Waterproof Binoculars

When binoculars are O-ring sealed, there is an air and watertight barrier between chassis, lenses and focusing mechanism of the binocular.

When binoculars are waterproof, they prevent moisture, dust, and debris from entering and damaging the binoculars internally.

Do I Need My Binoculars to be Waterproof?

Yes. You need waterproof binoculars for a couple of reasons. Even if you think you might be using your binos on sunny days only. but there are a couple of reasons why you should still get binoculars that are waterproof.

Firstly, having binoculars that are waterproof prevent water from entering and also block dust or debris from going inside the interior to block your view.  This is necessary especially in dusty and dry environments to help you enjoy using your binoculars for a longer time.

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Secondly, even if you don’t intend to take your binoculars out in the rain. There is still mist in the air due to rapid changes in temperature. This can cause moisture to built up inside the binocular. Therefore to prevent mist from entering the interior of your device, it is advisable to get a pair that is waterproof.

Thirdly, to prevent fungus and molds growth inside the interior of the binoculars,  its best to fully seal them to inhibit these bacterias growth.

Are All Binoculars Waterproof?

Sadly, the answer is no. Not all binoculars are waterproof. You will find some of the very cheap binoculars are not waterproof in any way and if you purchase them, you then have the responsibility to ensure water does not enter them.

However, almost all fog proof binoculars are somehow waterproof because the gases often used to prevent fogging in binoculars are Argon or Nitrogen and to keep either of these gases inside the binocular, the interior is sealed. Therefore, fog proof binoculars are waterproofed but not all waterproof binoculars are fog proof.

Fog Proof Binoculars

In high humidity environments, when you subject any optical device to rapidly changing temperatures, the lenses turn to fog up. This makes viewing through your binoculars not so pleasant.

So in order to prevent this from happening, manufacturers use either Nitrogen or Argon gas to purge the binoculars. These are the common gases used. There are others which are less popular. These gases have no moisture content and therefore do not cause condensation inside the optical device.

The oxygen is removed from the binocular and replace with the inert gas( argon or nitrogen). when this is done, the gas is sealed inside and that is why I earlier on said all fog proof binoculars are also waterproof but not all waterproof binoculars are fog proof.

These days, you can get affordable binoculars that are both waterproof and fog proof.

Nitrogen or Argon: The Debate of Which is Better

There is currently a debate on which of the two gases gives better fogging protection. Some people argued that Argon gas is better than the Nitrogen gas in terms of fog proofing because Argon gas contains larger molecules and therefore can sustain its attributes over the broader temperature range and has more resistance to diffusion or leakage.

While on the other hand, others claimed that there is no difference between them as both are dry gases. Since the atmosphere is about 78% Nitrogen gas, it is as good as the Argon gas.

Advantages of Waterproof and Fog Proof Binoculars

Fog proof and waterproof binoculars have great advantages over those that are not. some of the good reasons why you should consider them are below

  • They last longer: When the optics are tightly sealed internally to prevent moisture, dust, and debris from entering them, these kinds of binoculars last longer than their non-proof counterparts. Wear and tear are reduced significantly.
  • The extra cost is worth it: In the market, you would realize that waterproof and fog proof binoculars cost extra cash. You might be wondering whether they are worth it. I will say definitely. Having your peace of mind while using them in bad weather conditions is worth the extra cash.
  • Better Construction: greater attention is given to these kinds of binoculars during construction to ensure they are actually water and fog proof. Therefore making them better quality.


JIS Waterproof Scale
The JIS (Japanese Industrial Standards) uses a 0 to 8 scale to rate how watertight a device is and is probably the one that gets used the most, for a very wide range of products:

  • JIS Class 0: The device is not protected
  • JIS Class 1: Device has protection against vertically falling water drops
  • JIS Class 2: Protection against vertically falling water drops when enclosure is tilted up to 15%
  • JIS Class 3: Protected against spraying water – Water sprayed at any angle up to 60º on either side of the vertical shall have no harmful effects
  • JIS Class 4: Fully protected against splashing water
  • JIS Class 5: Protected against water jets – Water projected in jets from any direction against the enclosure shall have no harmful effects.
  • JIS Class 6: Watertight – Having no entry of water into inside by receiving direct jet of water from any direction.
  • JIS Class 7: The device remains dry after temporary immersion in water
  • JIS Class 8: The device remains dry during continuous immersion in water

Applications  of Fog Proof and Waterproof  Binoculars

Waterproof and fog proof binoculars can be used for every application. I can’t even tell a scenario where they are not needed. Here are the most popular applications of these devices.

  • General Use
  • Marine
  • Rainy and high humidity environments
  • Dry and Sandy environments

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