How to Keep Binoculars from Fogging Up

Binoculars are by far the most versatile optics for outdoor applications. They make a handy companion for outdoor enthusiasts who enjoy spending quality time outdoors. Whether your hobby entails hunting, birding, wildlife watching, ocean viewing, astronomy, hiking, camping or any other activity, a good pair of binoculars is an important item to have.

However, binoculars have the problem of fogging up which can interfere with the clarity of your views. The fog build up can be on the interior sides of the lenses or the exterior side. No matter where the fog builds up, it will reduce visibility and cause problems for your outdoor activity.

Why Do Binoculars Fog Up?

Buildup of fog in binoculars occurs when condensation of water vapor takes place. The moisture droplets in the air condense whenever you move the binoculars in two different locations where there is large gradient in temperature and humidity levels.

Additionally, the fog can form on the lenses when you hold the binoculars in in front of your eyes for a prolonged period of time or breathe cold air on the lenses. This results to formation of a thin layer of water droplets on the lenses.

It is annoying when this occurs and you will want to know how to keep binoculars from fogging up to have a clear field of you. You can wipe the lenses clean if the fog is on the exterior surface only. However, if the fog builds up on the interior side of the lenses, it can be a big headache.

You will have to dry the moisture inside the binoculars fully and this can take some time. Besides, entry of moisture inside the binoculars can be detrimental to the optics inside.

How to Prevent Build Up of Fog Inside Binoculars

Given the danger of condensation taking place inside the binocular’s lenses, it is important to take extreme caution to ensure that it doesn’t happen.

The simplest and most common way to prevent internal build up of fog in binoculars is to purchase a model that is rated to be fully waterproof and fog resistant. The binoculars should have a certain level on IPX rating with the IPX-7 rating being the best.

Binoculars with an IPX-7 water resistance rating are fully waterproof and dustproof as well. Additionally, the it is best to pick a pair that is filled with inert gas preferably argon or nitrogen. This helps prevent moisture contamination and subsequent buildup of fog both on the surface and interior side of the lenses.

How to Make Binoculars Fog Free

If the binoculars you are using are not fully waterproof and fog proof, you can make them fog-free by following these easy steps.

1) Store the Binoculars in a Dry Place

When you are not using the binoculars, make sure that you stow them in a place that is dry and moisture-free. You should put them in an airtight box. If you live in a place where the temperature and humidity levels keep fluctuating, it is best to invest in a desiccant and put it together with binoculars in an air-sealed box.

The desiccant will absorb the moisture both in the box and on the exterior surface of the binoculars and alleviate the chances of the binoculars fogging up.

2) Use an Anti-Fog Product when Cleaning the Binocular’s Lenses

Whenever you are cleaning the binocular’s lenses, try and use an anti-fog agent together with the cleaning solution. Anti-fog products come in different forms from drops, sprays, wipes and much more.

If it is hard for you to access an anti-fog product, you can use your saliva. There is a compound in human saliva that helps reduce fogging of glass surfaces.

3) Temperature Adjustments

Leaving the binoculars to adapt naturally to your local temperate and humidity levels can help counter fog buildup. To achieve this, you should leave the device in a location where it is exposed to the outside weather conditions for about 30-60 minutes.

4) Use the Binoculars in Favorable Weather

While this can be difficult, using binoculars in dry weather only can keep the lenses fog free. Weather changes happen when we least expect it and when that occurs when you are out in the field, try and not use the binoculars.

5) Avoid Large Temperature Differences

If there occurs a large difference in the level of humidity and temperatures, the binoculars will fog up instantly. However, if the changes in temperature are negligible, no moisture will condense on the binoculars.

If you are outdoors and the temperatures change abruptly and become too low, you can put the binoculars inside your pockets where they will be closer to your body. The warmth your body generates can help prevent condensation from taking place.

6) Dry the Binoculars

If there happens to be moisture on the inside of the lenses, knowing how to keep binoculars from fogging up will not only provide clear views but also safeguard the interior optics from damage. In such an event, you must dry the moisture fully or binoculars will continue to fog up all the time. You can try to leave it for a while for the moisture to escape or put it in a bowl of rice and leave it for about 1 day.

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Benefits of Buying Water and Fog Proof Binoculars


Fog proof binoculars tend to offer greater durability than normal binoculars. They are fully sealed and filled with gas to ensure that no moisture damage happens.


When the binoculars are built to be fully waterproof and fog proof, it will never allow water, dust and fog to get inside the optics. This saves you the hassle of having to clean the fog every now and then.

All-Weather Reliability

Binoculars that are fully waterproof and fog proof are ideal for use in any environment. You can use them when it is raining heavily and it won’t get damaged. Besides, the binoculars can accidentally fall in water and stay undamaged. It will also be convenient to use the binoculars when the temperatures change rapidly and with a large gradient when you are out in the field.

Value for Money

While fog proof and waterproof binoculars are costlier, they are certainly worth the cost. Thanks to their durable construction and all-weather performance, you will be able to get many years of use. They also require little to no maintenance which helps save on cost in the long run.

Final Thoughts

If you are a serious outdoorsy kind of person, it is wise to invest in binoculars that are fully waterproof and fog resistant. If the pair that you own is not fog proof or water resistant, we hope that we have answered you question on how to keep binoculars from fogging up.

Follow the easy steps listed above and you will always have clear and fog-free binoculars for your outdoor expeditions.