View Full Version : How do you stop your scope from fogging up?

01-13-2008, 07:04 PM
I have had a few issues recentley with shooting in cool, wet or foggy conditions when my scope fogs up. No doubt I have breathed on the scope and such, but even when out hunting, I have gone to look through the scope and it has fogged up. (only externaly, not on the inside lenses). What do you do to stop them fogging without altering the quality optics?
I would like to stop my Zeiss scope from fogging without screwing up the great Zeiss optics.

01-13-2008, 07:42 PM
one trick is to keep it in constant temperature...

Lets say you're hunting and it's cold outside, keep the gun outside in between hunts, bringing it in and out will surely fog it up.

If your outside and it's cold, and wet don't cover it up with anything like a hat or glove or anything. Keeping it a constant temperature is the key.

Also, this really isn't centerfire benchrest topic, so in order to stay on toic, the Factory / Hybrid guys might have more advice for you as well.

01-13-2008, 08:19 PM
pbike, the last time I had this problem ,and what made me post was when I was in a competition. It started raining just before my relay and the scope got covered as the wind was blowing the rain about. A rain drop was just where the crosshair was and when I wiped it, it made the image look like I was looking through a coke bottle. When I eventualy wiped it down, whenever I accidently breathed on the scope, it would fog up.(this was a Leupold BR scope)I have another Bushnell scope with "rainguard" and the water just beads up and falls off. I was wondering if Benchresters use any sort of thing to act like this?

Victor N TN
01-13-2008, 08:27 PM
Swimmers use stuff called "Cat Crap" to keep their goggles from fogging. Go to your local sporting goods store or back packing store. They probably have other products that work also.

I hope this helps.

01-13-2008, 09:13 PM
"Cat Crap" such a lovely sounding name for some goo to put on the lense of your favourite scope. I have seen it around somewhere and will give it a go to see how it goes for me.

01-13-2008, 09:15 PM
A trick that I learned years ago is to use clear lotion rubbed onto the lens really good. It stops the fogging very well.--Mike Ezell

J. Valentine
01-13-2008, 09:50 PM
In the good old days when people went to drive in movies we used to cut a potato and rub it on the inside of the windscreen to stop it fogging up due to the interior body heat if you get my drift.
Would rub it on and let it dry a bit then slightly polish it off with a soft rag.
Seemed to work ok from what I can remember.
Don't know if it can hurt a scope lense coating though.

01-13-2008, 10:23 PM
Clarity Fog Eliminator available at Amazon: http://www.amazon.com/Clarity%C2%AE-Fog-Eliminator-2-3-packs/dp/B00069DN86/ref=pd_sim_hpc_title_3 or try EK's Cat Crap: http://www.sunglassesgiant.com/catcrap.html

01-13-2008, 10:31 PM
In the past I've used Birchwood Casey lens cleaner .

I have a free sample of Fog Tech to check out now -thanks guys. http://motosolutions.com/cindex.html

Shooting a Benchrest match in quite cold weather in Canada this stuff works.

I would call or email Zeiss and see what they recomend.


01-13-2008, 10:44 PM
Clean (wipe on/wipe off) the lenses with a very very small dab of "Foamy".

Try it out on a foggy bathroom mirror first if you must....

01-13-2008, 10:53 PM
"Before going outside, put the lens in a ziplock bag and leave it outside till the body temperature of the gear changes to the outside temperature. When it does, take it out and use it, this way it will not fog up because there is no sudden change (to the gear) temperature wise." It's worth a try.

Larry Elliott
01-13-2008, 11:22 PM
Another place to check might be a motorcycle shop to see if they have anything to keep helmet face shields or eyeglasses from fogging up in humid conditions. I had some stuff many years ago that I can't remember the name of (and it'd likely be different in Oz anyway) that worked like a charm. I've heard that there are a few motorcyclists down under :D so it might be worth a try.

01-13-2008, 11:29 PM
While we are talking about cat crap, clear lotion, and potato juice, why not try what snorklers and skin divers do, spit on it!


01-14-2008, 12:58 AM
It was at a motorcycle shop today that I saw the Cat Crap. I,m not sure if it will have any adverse effect on expensive scope optical coatings.

01-14-2008, 01:14 AM
Many years ago when the first Weaver T-10's came out I bought one and went to the scope repair shop to set up the A.O. on their test target. The old guy cleaned the lens and set it in the holder.
I focused that scope and set it up parallax free on the test target. The tech touched his nose -then the front lens and walked away saying "Check it now. " You could not see anything on that lens but there was a 1/2" of movement now.

I would check this carefully and make sure that what ever you use does not damage the lens coating.


01-14-2008, 07:46 PM
The external surfaces of your scope are subject to fogging anytime the temperature of the lens falls below the dewpoint temperature of the air. If the scope is warm it will not externally fog up. If the scope is 50 degrees and some 55 degree dewpoint air blows in it will condense on the lens surface. The dewpoint of the air you exhale may be around 90 degrees or so.

J. Valentine
01-16-2008, 12:55 AM
There is some comercial products that you can use we used it in the Military but I can not remember any brand names. The thing that would concern me is to make sure any product you buy is safe for scope lense systems.
You dont want anything attacking the lense seals.

01-16-2008, 01:15 AM
Well, what I will do with my good scopes is not put on any anti fogging potions unless I hear from the manufacturers that it is OK. I will just have to leave it in the back of the car with the tail gate open to even out the temperature between relays. I think that what I have been doing is putting the scope caps on and stuffing it inside the gun case between relays.

John Kielly
01-16-2008, 01:39 AM
I think that what I have been doing is putting the scope caps on and stuffing it inside the gun case between relays.
That reminds me of what's is sometimes a real issue when you travel around all over the country. The foam in gun boxes sometimes takes up quite a bit of moisture which is only to happy to precipitate on any cool surface given the right circumstances - like leaving it in a cold car overnight.

I've seen rifle actions covered with surface rust from an injudicious overnight storage.

I regularly toss my foam into a dryer with a few towels to drive the moisture out.

01-16-2008, 10:14 AM
While hunting Canada with a very nice 6.5-284 built by MWEzell I couldn't keep my binocs or scope free from fog due to the low temperature. For the binocs, I kept them inside my coat, therefore warm, that helped with the binocs. For the scope I used two methods...first was to put one of those single-use Hot Hands in my scope cap...that kept the occular warm and fog free, the other, and perhaps slightly obscure way, was to rub the side of my nose, and use your skin's natural oil as a coating. Worked in a pinch, but the handwarmer trick was the best.


01-16-2008, 02:40 PM
Rain-x anti fog is available at auto parts stores and even keeps the bathroom mirror fog free after a long hot shower. Unbelievable stuff.

Big Caliber
02-02-2008, 06:18 PM
Snorklers use this in Hawaii... Johnson's Baby Shampoo. Just apply a thin coat to the lens and let it dry to a haze. Then wipe it off with a lens cloth. Oh, it HAS to be Johnson's baby shampoo, the other brands don't seem to work. Happy scoping.

02-02-2008, 07:00 PM
I use Bushnell Elite 3200 and 4200 scopes with Rainguard. I know that this doesn't solve the problem with your Zeiss but you may want to take a look at the latest scopes from Bushnell, I have a 4200 6-24 with side focus that optic wise I will put up against anyones scope. As of March 2008 they have a 6500 series (6-30 magnification) and if they are as good as the 4200 series they will be the new standard for the dollar value.

02-03-2008, 02:23 AM
Drover, due to the very poor warranty service I have had in Australia with my previous 4200 series scopes, I will not buy another Bushnell or Tasco scope. I have decided that I will try using spit on the lenses as I dont want to risk the lenses of my good scopes with other unknown chemicals.

02-03-2008, 10:28 AM
I have read quite a few comments on Bushnell's poor warranty service on various sites but have never experienced it myself. My only use of their warranty service was when I sent in a pair of garage sale purchased binoculars that needed repair they promptly replaced them with a new pair, so in my limited experience I was satisfied.

I have been running B&L 3000 & 4000 and Bushnell Elite 3200 & 4200 series scopes for the last 10 years and have yet to have one fail. I also have a dozen or so Leupold varmint and competition scopes so I am not locked into any one manufacturer, rather I just feel that at this point Bushnell has some real advantages considering pricing and features, particularly when it comes to the rainguard and their pricing.
If I someday have a repair issue then my opinon of them may change but I have had repair issues with Leupold and I still use them.

chuck furniss
02-03-2008, 12:54 PM
Fog Zero. I sell this at my store,it works,I use it on all my optics as well as my eye glasses. Safe for coated lenses and plastics.
Beware of raingaurd and similar products as they contian strong solvents.
Web site is www.fogzero,com.

Fred J
02-03-2008, 01:14 PM
Can't get the site to open

02-03-2008, 02:15 PM
try this site.http://www.1888fogzero.com/

02-04-2008, 02:30 AM
Drover, the poor warranty service I have had from Bushnell has been here in Australia, where Tasco does their warranty work. I have spoken to a few people here who have said forget about sending any sort of (Tasco or Bushnell) warranty work to Tasco in Australia. It might be different in USA.

Chuck Furniss, this fog zero looks like something to try. I dont know if I will put it on the lense of my Zeiss scopes or my new Swarovski Z6i. I will trial it on some of my lesser scopes, but would be interested to here from Zeiss or Swaro if they condemn or condone it on their coatings.

Tony Z
02-04-2008, 07:58 AM
Shoerooter, i would have thought the only problem you would be having with scopes down your way would be all that coal dust coating the lenses:D.
A simple answer to your fogging problems is to just move on back to North Queensland:cool:
How did that bolt work out in your FS rifle?
Take care.
Tony Z.

02-05-2008, 02:24 AM
Tony, the bolt worked out well. Thanks for that.
I moved down here as I wanted to get away from the rain and I heard there was a drought down here. It has done nothing but rain since I moved here.