How to prevent binoculars from fogging up

how to prevent binoculars from fogging up

Binoculars are often fogging up when there is a difference of temperature from indoors to outdoors, as when taking your binoculars outside on cold-like temperatures (e.g. from 25*C to 0*C). This is a common issue which glass-wearer people may have to deal with.

How to prevent binoculars from fogging up? There are several ways to do it, the first thing is to expose your binoculars to smaller differences of temperature to avoid fogging up, to wipe the outer lenses with a cloth when this happens or to apply a special gel or product on the lenses which allow your binoculars to decreases the fog condensation.

But thinking about how binoculars will fog up, there are two types of fogging or condensations which can occur to binoculars when you expose them to different temperatures: The outer fogging or the inside fogging.

In this topic, I want to explore with you different types of fogging on binoculars, how to prevent that and if there is any way to minimize or completely avoid the condensation inside the binoculars. I would recommend you to keep reading.

How to prevent binoculars from fogging up

The car windshield, your glasses if you wear any, your camera lenses, binoculars or even your home window, when all those are subject to a major difference of temperatures, the glass is getting blurry, or how the popular terms sais, fogging up.

The condensation is a natural process and more humidity is in the air, the chances for the binoculars or any other glass objects to fog up is higher.

There are a few ways to avoid this, if possible the first one is to take the binoculars through a slow-cooling or warming process with smaller differences of temperatures. This is not very practical as there are not many ways you can do it, and although you do this, remember that the body temperature of the binoculars will pressure the change a bit harder due to the density or material the binoculars are manufactured.

Some special fog-resistant glass may exist on the market which contains a special layer which reduces the amount of fogging can happen to the binoculars.

But furthermore, we all tend to do one thing: to wipe the blurry lenses and to continue using the binoculars. Is that a bad or a good thing?

Wiping the condensation when this happens

It’s an okay thing to do. Just keep in mind that the fogged glass is actually water and when you quickly wipe the binoculars, this is not getting cleaned, therefore, a bit of mess may become present on the binoculars glass and spread on the surface.

The first thing I would recommend when you are wiping the fogged binoculars is not to give a quick wipe but to clean the glass properly as you are doing it when this is dirty – in this way you ensure the binoculars glass will remain clean.

In general, when you perform this, the binoculars tend not to fog up anymore because of the level of humidity present on the glass surface, but not always the case. If this happens again, repeat the process.

Applying special gels or products on binocular lenses to avoid fogging up

Anti-fog treatment is largely available on the market but beware of what you are buying – although the anti-fog treatment can drastically decrease the level of misting on the outer lenses of your binoculars, this tends not to last very long, and will not have any effect for the inside condensation (wherever is the case).

One another thing to keep in mind is the product you are using – as many as large is the internet, some of the products can do more harm than good to the binoculars glass and this can void the warranty. Research first if you are intending to buy any anti-mist treatment for your binoculars.

Aforementioned does not must be a specific product “Your binoculars the perfect anti-mist treatment), is, in general, the same products which can be applied to eye-glasses or anything else to avoid misting up.

The outer condensation on the binoculars

This is the most common form of misting or condensation on the binoculars – when the ocular lens or eyepiece is getting misted or fogged on the outside, and there is no damage done to the binoculars.

Following the above advice is the best way to ensure that your binoculars are remaining mist-free and for those to ensure the best quality of observations.

The condensation occurring inside the binoculars

This is the worst part when some of the binoculars will form condensation inside. In this case, there is not much you can do, just to wait for the binoculars to clear up.

Beware, and I advise you to be very careful if the binoculars are misting on the inside, because the performance of the binoculars is diminished in time as mould or fungus can grow inside the binoculars, as long as there are the main elements for this to happen: warm temperature, humidity and oxygen.

The best way you can avoid this is in fact to have a pair of binoculars which is waterproof, weatherproof and fog-proof. Shortly? Nitrogen-purged binoculars.

When the binoculars are nitrogen-purged, all the humidity is removed from inside the binoculars when they are assembled, nitrogen-dry gas is purged inside and the binoculars are sealed with an O-ring rubber. The binoculars will NOT fog on the inside anymore which drastically improve the quality of the binoculars and the longevity of them.

The advantages of a nitrogen-gas binoculars.

I have a pair of binoculars, Nikon 7S 10×42 which I always keep them in the car wherever I go. During cold weather, the temperature of the binoculars will match the outside temperature (as the car is parked into a garage). When I drive and warm up the car, the binoculars are fogging up. This is not a good practice if the binoculars are not fog-proof or nitrogen-purged as misting can happen inside the binoculars, but for my Nikon model, is not the case, therefore, after a thousand or more times where the condensation occurred, the binoculars quality remains the same – I wanted to point this out as if the binoculars were not fog-proofed and nitrogen-gas purged, long-time would be gone since I would have to change the binoculars as damage already may occur.

If you want you can read of our other article “why are binoculars filled with nitrogen gas?” for more information.

Conclusion of how to prevent binoculars from fogging up.

Condensation / fogging / misting on the binoculars glass, either on the outer side or the inside, is a common fact which can be avoided in certain situations, while in some other situations cannot be avoided.

This is not something to worry too much about it but beware of storing the binoculars for a longer period of time, in special in places where is a major difference of temperature between day and night or high humidity. I would recommend you to store them in a vacuum-sealed bag to avoid as much as the possible the above problems.

If often condensation on the inside of binoculars occurs, there can be formed drops of water, dripping on the inside glass or fungus/mould, where any of these can impact negatively the quality of the binoculars. If you may think any of those happened, I would say for you to send the binoculars to a specialized shop for a full-clean-up.

In the situation of where yet you do not have any pair of binoculars and you want to buy something, I strongly recommend you to look for anything to be “nitrogen-purged” to avoid all the problems of inside condensation.

Did you know that condensation can also happen on the armour body of the binoculars and the rubber (if this is armoured with rubber) can degrade in time?

Thank you for reading this post to the end and I hope you keep your binoculars safe. For now, I have to say goodbye and take care!

Gabriel Mihalcea

Passionate about binoculars, photography and blogging with years experience behind, I love to split my time and observe the beauty of this world with different eyes.

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