Fog Prevention-Is It Possible?

[Markie Madden]

I'm putting this here because I imagine it is a pretty basic question that you get asked time and time again.

I sometimes get the chance to sneak out and get some shots of animals or birds. I usually put my camera onto my mono or tripod while still in the house, turn it on, and take off the lens cap. If the -pod has been folded down, I'll adjust it for my height as well. Then I'll step outside.

This has been a problem lately as it's been extremely hot as well as humid outside, and it's nice and cool in the house. So my lens fogs up. Is there anything I could put on it, like Rain X anti fog, that will help reduce this? Or would that be damaging to the lens?

 

[jsecordphoto]

Do not put rain x on your lens. Sometimes when out photographing at night condensation starts to form on my lens, I just wrap a hand warmer around it with a rubber band. They do make products specifically for this, but I find it way cheaper to just use hand warmers

 

[Markie Madden]

Would that help in my situation? Going from cool to hot?

 

[Designer]

Would that help in my situation? Going from cool to hot?

The reason it fogs over (condenses moisture) is because it is going from cool and dry to warm and humid. Your camera and lens became cool by being in the A/C. By allowing a bit of time for the camera and lens to come up to outside temperature, it will not condense moisture. If you are at home and it's not raining, you can set your rig out on the deck half an hour or so before you expect any animals to appear.

 

[TCampbell]

There's nothing you (as a consumer) can apply because unless you're using weather-sealed lenses, the lenses can still fog on the inside and there's no way for you to apply any coatings to the insides of your lens elements (not without voiding the warranty). Some lenses have coatings that help resist fogging.

But ultimately fog (condensation) forms because the camera is colder than the "dew point". The amount of moisture that the air can hold is based on the temperature and pressure of that air. This is why it's called "relative" humidity and not just "humidity". As the air temperature drops (or pressure drops) the air can't hold as much water and some water will condense and fall out of the air.

Take a cold glass out of the refrigerator and you'll notice the sweat building up on the glass surface. It only does that because the temperature of the glass is COLDER than the "dew point" temperature. If the glass had come out of a warm oven then condensation wouldn't form on the glass even if it was forming on everything else around you.

The point... is that if you don't store the camera in a cold environment (any environment colder than the dew point temperature) then it won't fog up on you.

Is there a place in your home that is not air-conditioned (or that the AC doesn't work very well?) If so, that might be a better place to store the camera when not in use.

We have a similar problem in astronomy (telescope optics fog up) except for us it's because the night time temperatures (when we are using the telescopes) are falling and the dew is forming on every surface (not just our telescopes). To fight off the dew, we use dew-heaters (warming straps that wrap around the telescopes to keep the optics warmer than the dew point so that moisture cannot condense on them.)

There is something you can do if you know you plan to go out shooting... IF you have a safe place outside your home (a non air-conditioned space... such as a garage) then you can keep the camera in a sealed bag, but put it in the warm environment. Since it's in a sealed bag, moist air cannot get in... and the camera inside will slow warm up to the temperature of the warm room. Now you can unseal the bag and start using the camera without fear of things fogging up (you might have to put the camera out perhaps as much as an hour early ... but even 30 minutes would be a big help.)

 

[Markie Madden]

Thank you, I understand now. I don't really have a safe place outside, except my laundry room which is at the head of the carport and is not air conditioned. But I'm currently running the dryer out there and it's roughly the same temp as the surface of Mercury, so I wasn't sure if it would make it too hot if I did that.

But I do have a bathroom (it butts up to the afore mentioned laundry room and in fact used to be the laundry room), and it does not have a vent in it. But it also contains the hot water heater (I shudder to think of storing any electronics in there!), but I'll try setting the camera there for a while and see if it improves.

I've also noticed the same thing with our telescope, but of course it's easier to set those up beforehand. Around here, you never know when the birds or animals might make an appearance!

 

[Designer]

You need to keep it away from the dryer exhaust, steam, bathrooms, or any place that is hot and humid. Extended exposure to such an environment could lead to other problems.

Short answer is; when you take it outside, just wait a bit for the temperature to equalize. I wouldn't even wipe the lens, just wait a while for the condensation to disappear.

 

[philsphoto]

Agree with Bryston. Camera needs to acclimate to the conditions. So like from condo to beach, camera should be in its bag outside in the hotter and more humid environment before you try and use it.


Sent by Phil s Photography Weddings Engagements Portraits from my iPhone using Tapatalk

 

[sashbar]

Put your camera in a sealed plastic bag and leave it in the trunk of your car for an hour prior to shooting, if it is safe in your area.

 

[dennybeall]

Another trick that works well is to consider that a cooler will keep the cold out just as well as in so you can put the camera in a cooler so it doesn't get so cold.