Scope fog
 

I was reading another post and someone was saying that their scopes never fogged. That reminded me:
Every one of my scopes have fogged at one time or another. I see manufacturers talk about waterproof, shockproof and fogproof. All of my Nikon's, Bushnells and my one Leopold fogs up from my warm breath on a cold day.

WHY???

RE: Scope fog
 

The change in the ambiant temperature of the glass and the warmth of your breath causes external condensation on the lenses.... But when a manufacturer speaks of fogproof, that is referring to the internal glass... The glass inside the scope will not fog due to temperature change or condensation because the scope is nitrogen gas , or Argon gas , purged and sealed with multiple O-rings and seals at any place where the scope has a joint or connection to the outside.

So every scope can fog on the outside glass due to your breath, but that has nothing to do with claims of being fogproof.

MET

RE: Scope fog
 

Very well explained by Michael T. The Rainguard feature on certain Bushy scopes helps a lot in that regard. Some other scopes have similar coatings or, in the Leuppy line, screw on pretective lens' that will help. Just try to not exhale directly towards the eyepiece whwnever possible.

RE: Scope fog
 

Thanks guys. I was unaware that teh manufacturer claims were referring to the inside of the scope not fogging.
That being said what do you guys do to help prevent the fogging on the outside. I seem to recall that when i was younger and did a lot of skiing i could put something on my goggles to stop them from fogging. Is there something we can put on the scope lense that would work and be safe for the lense?

RE: Scope fog
 

Some companies ( not scope companies ) make anti fog sprays or creams, but the best way is to not breath directly on the lenses. If you are looking through the scope at an animal, in cold weather, breath through your nose, and train yourself to do so every time.

MET

RE: Scope fog
 

Yea, the outer fogging is common. If one fogs on the inside, and some how clears up, its still a lost cause. They will contiune to do so.

RE: Scope fog
 

an excellent post.....well done.

RE: Scope fog
 

Vapordog - you da man.
If yo can find it, a good product for anti fogging your scope lens is called scope dope. It comes in a little orange plastic container. Its almost like a wax for glass. It works great on scopes, binos, spotting scopes, even eyeglasses.

RE: Scope fog
 

RAIN -X Anti Fog does pretty well.

RE: Scope fog
 

Thanks Swampy.
I was just going to ask about the Rain-X since I already have some for the car.

In addition to preventative products and thoughtful breathing practices, I recommend keeping a clean dry soft cloth handy to wipe fog off if it does happen. It may save you a lost shot, and you really don't want to use your finger or a dirty glove if you can help it.

RE: Scope fog
 

Are you guys afraid of putting Rain-x on your scope? Has anyone already done this?

Tom

RE: Scope fog
 

Be careful with Rain X. Its good stuff for car. But it may damage the seals in the scope. I'm not sure what is in it.

RE: Scope fog
 

Butler Creek scope caps are cheap/easy insurance...........

RE: Scope fog
 

I have heard, from others, that Rain-X and scopes should not be mixed. Never tried it myself. I have used a spray called Parker's Perfect that seemed to work o.k...not great but o.k.

RE: Scope fog
 

Im having flashbacks to last day of the 2005 buck season. Blue ball cold that morn and I see a 6 point trotting across the other side of the holler...first thing I do is get excited and breath on my scope..lol. Thankfully the deer wasnt moving fast and the fog left quickly and there was t'loin on the stove in the cabin that night.

RE: Scope fog
 

Use to be a common thing to have a scope fog up internally, especially "if" you hunted in freezeing/thawing weather. Just hunting all day out in freezing weather and then bringing your rifle into a warmer tent would sometimes do it.

I can remember leaving my rifle out in the cold for entire hunts, rather than take a chance on my scope fogging.

I was spending a lot of time hunting in weather like that, so i started testing my new scopes by putting them in the freezer for a day or two. Then i'd put them in a pan of warm water and look for bubbles rising. It i saw the teltale bubbles rising, i knew that scope wasn't going on my rifles, untill it took a trip back to the factory.

These days scopes are sealed up much better than the older scopes were. With modern O-rings ect., it's got a lot easier on the scope mfg-ures...

A friend wrote an article on Mueller scopes, and while he was doing so, i suggested he give it the freezer/warm water test. I told him i wouldn'twant one on a gun of mine, "if" it couldn't pass that test.He took the challenge and froze the scope. A day later it went into a pan of warm water, and no bubbles came up.

Use to be, cheap scope= a scope that fogged! Not any more...

DM