Re: Preventing Lens Condensation

E

ectobuilder

Veteran
Re: Preventing Lens Condensation

I was filming from a very cold environment to a warm environment and my lens fogged up tremendously as I transitioned from low to high temperature. Is there anything I can do to prevent this?
 
I don't have a ton of experience with this but i can tell you for my loupe on a cold day used to get fogged up while i used it so i got some scuba defogger and put that on there. It needs to be re-applied every few months but it worked fairly well for my purposes. I would give this a try but only on a UV filter that you aren't super worried about losing.
 
What I do is I try to have the camera or lens in it's case in the cold temperature and leave the stuff in there for a 1/2 hour. Then when you take it out it will be fine, same thing going inside to where it's warm. Have the unit in a sealed case, even a plastic bag, and let the temperature change happen with it in there and you won't get condensation.

I would not apply chemicals to the lens because I'd be chicken that it would do something with the coatings.
 
ectobuilder said:
I was filming from a very cold environment to a warm environment and my lens fogged up tremendously as I transitioned from low to high temperature. Is there anything I can do to prevent this?
Click to expand...

Prevent the laws of physics? I hope not! :D

What's causing this is the amount of water vapor in the air. At cold temperatures air can hold very little water. At warm temperatures is can hold huge amounts. When you bring a cold object into warm air, the air in a immediate vicinity of the cold object cools and suddenly finds itself holding more water vapor than it can handle. So the water vapor has to come out -- it condenses onto the surface of the cold object. Or... it just condenses (forms a cloud). Yep, this is the same basic reason clouds form.

You can avoid this in a few ways. Two come to the top of my head right away. First, warm the camera up before bringing it into the warm air. Seal it in a bag while in the cold environment (the cold air you seal in with it will also be very dry), bring the bag containing the camera into the warm environment, and wait for the camera to come to temperature. This works, I've done it a lot.

Second, make sure the warm environment is also very dry. Dew point of the warm air has to be lower than the air temperature of the cold environment. Then there's not enough moisture in the warm air to condense out. This would also work, but unless you're in the desert it's largely impractical.
 
Pre Warming is key.

Often done with a car heater or maybe take your lenses into the toilet and get them under the hand dryer, basically my standard practice in swimming pools, gyms and the like.

S
 
As everyone else has pointed out, it's the warm air causing condensation as it hits the cold glass. The best thing is to just not plan on shooting anything for an hour after being in the cold all day. Less time if you've just popped out into the cold and back. If you really have to shoot indoors right after being in the cold there's a few strategies you can try.
1. Keep a second camera setup stored indoors. I did this a few times when I used to shoot winter events that had awards given out indoors. Obviously it won't work if you don't have two sets of gear and a secure place to keep them.
2. Wait. Keep the camera bag closed and let it slowly change temperature without exposing it to the warmer (and usually moister) air, thus avoiding condensation.
3. Plan ahead. Bring the camera in well ahead of needing to shoot so you can take advantage of option #2 and not need to take the camera out.
4. Heat it up! Blast it with warm DRY air to get the temperature the same as what you're shooting. This is probably the least recommended way as lenses have many elements inside making it difficult to warm up quickly without causing condensation somewhere else inside the lens. There's also the chance that rapidly warming could cause damage from expansion/contraction when warm and cold parts expand at different rates. This would be a last ditch method if the shot is more valuable than your gear.
 
I carry one or two 1 gallon ziplock bags in my camera bag. While out in the cold put the camera with lens mounted in one of the bags. Once inside take the ziplock bag with camera out of the bag and hold it in close to your body, moving it around until it no longer feels "cold".

Depending on camera size, inside temp in the room, this may only take about 15 minutes or so. Do a "practice run" and see how it works with your gear.

Ziplock bags are also great equipment insurance if you get caught in heavy rain. A camera bag can get soaked all the way through in short order.
 
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