Go Pro Fogging

[AggieDad]

Heading to Roatan next week and my buddy and I both have Go Pro Hero 2 and the flat port with red filters but we have been told there is a fogging problem. I am at a loss to explain this because the case is so tiny AND if one used the same precautions i.e. not opening the case in the boat but only in an air conditioned room...why would it fog? If so what are some fixes?

 

[JamesK]

I have never had any of mine fog. However, friends have. No clue why as we did not do anything different, that I know of. GoPro does make anti fog inserts that go inside your housing. They should be available anywhere GoPros are sold.

---------- Post added April 29th, 2012 at 09:56 PM ----------

Anti-Fog Inserts - GoPro Official Store: Wearable Digital Cameras for Sports

 

[Marty Cerven]

The GoPro doesn't have much room in the housing but it can generate quite a bit of heat and if you use the LCD it will generate even more heat. It doesnt take long for the little amount of air in the housing to heat up enough to cause condensation. The Hero2 does get much warmer the the original HD hero so it will also be more prone to fogging. It may not happen but I would rather ensure it doesn't then take the un-needed risk of losing all my footage to fogging.

The air conditioned room may work for you but a better option is to close the housing with the air conditioner blowing directly into the housing.

You can also use air from your scuba tank by filing a plastic bag with the air and closing the housing whilst inside the bag. This air is very cool and dry and if done properly there wont be enough moisture in the housing to cause condensation.

Either or the other 2 methods should work but the air tank will be much more reliable, but either method will fail the moment you open the housing to open air for any reason.

The other option is to use desiccant packs, the GoPro anti fog inserts or anything similar. Make sure they aren't saturated and most of these can be heated in an oven to un-saturate them. This is the Method I use with some desiccant packs I bought from a dive shop but when using the LCD the only ones I found small enough where the GoPro ones. The advantage of this method is that you will get away with opening the case to change batteries or memory cards but you still need to avoid any un-needed exposure to open air to avoid the desiccant getting saturated.

 

[dfx]

The GoPro doesn't have much room in the housing but it can generate quite a bit of heat and if you use the LCD it will generate even more heat. It doesnt take long for the little amount of air in the housing to heat up enough to cause condensation. The Hero2 does get much warmer the the original HD hero so it will also be more prone to fogging.

Huh. Wouldn't heat reduce fogging? Warmer air can dissolve moisture better, so it has less reason to condensate.

 

[Marty Cerven]

Huh. Wouldn't heat reduce fogging? Warmer air can dissolve moisture better, so it has less reason to condensate.

When warm moist air comes in contact with a cold surface, the water held in the air as vapor condenses into tiny liquid drops as it cools against the surface. This water then turns to fog due to the heat in the housing so you need to reduce the water content inside the housing to avoid these droplets forming in the first place.

Its more of an issue in either cold water temperatures or very humid climates but with the GoPro generating a rather large amount of heat this will easily warm the air temperature inside the housing well above that of the water outside. This will cause condensation to form, using cool very dry scuba tank air is a great way to ensure this doesn't happen as the air is very dry and even heated up doesn't have enough moisture to do this. The same with desiccant which once installed in the housing it will absorb all the moisture inside the housing which also prevents the same issue.

 

[billwil]

Marty, I think what dfx was (correctly) pointing out was that warmer air has the capability to "hold" more moisture before it condenses. You're tips are excellent because they close the case with cool, dry air. As you (also correctly) pointed out, this greatly decreses the chance of condensation (because the air when closed both had less capacity for holding moisture AND actually had less moisture). Once closed, the heat from the camera shouldn't have any effect on condensation; that is simply an equation of the amount of moisture in the air and the temperature of the surface of the housing. Then again...what do I know?

Again, excellent suggestions for people having this issue...I'll certainly keep them in mind (I've been only using desiccant packs...not tank air). Thanks.

 

[Marty Cerven]

What DFX said is correct that warm air will hold more moisture but the thing that causes the condensation or fogging is the temperature difference between the inside and outside of the housing, the heating of the air inside the housing causes the temperature difference and therefore the condensation. This is also why setting up your housing in a cool air conditioned room will reduce the chance of fogging as the cooler air has less moisture in it to begin with so a bigger temperature difference may be needed to cause the condensation. Because there is not much air inside the housing it heats up pretty quickly and why its more of an issue then with a larger camera that has more air in the housing.

To ensure it doesn't happen at all you need to reduce either the moisture content of the air in the housing or stop this air from heating up relative to the temperature outside of it. Seeing the camera is generating its own heat and going from air to water will most likely caused a temperature difference you need to reduce the moisture content so that it cant form condensation once its heated or the outside temperature drops.

Where Im from in Melbourne Australia we get the famous 4 seasons in a day with huge shifts in temperatures, a strong northerly wind can reach temperatures up to our record of 49.9c and a wind shift to the south can easily drop this to below 20c. Water temp varies from 21c mid summer to about 9c mid winter so quite regularly there is more then 20c difference between air and sea temps here.

This is why I always use anti fogging methods since my first gopro test dives all fogged up. Since that day I bought some desiccant packs from a dive shop and never had any issues, only other time I got fogging was when I had dog cam running and he walked through a cold stream of about 8c water temp. I had no desiccant in the housing and it fogged up instantly as soon as it went into the water, this reinforced my anti fogging practices and Ive had no issue since.

I don't use the scuba air method but I have a few friends that do in the same conditions and they have also been fog free this way. I'm far from an expert myself lol but have a bit of experience with these cams and have read much about this issue and just go by these basic rules.

 

[dfx]

When warm moist air comes in contact with a cold surface, the water held in the air as vapor condenses into tiny liquid drops as it cools against the surface. This water then turns to fog due to the heat in the housing so you need to reduce the water content inside the housing to avoid these droplets forming in the first place.

Correct, but here's the thing: the air inside the camera case isn't "warm and moist". It is whatever it was when the case was closed, which is the same no matter how much heat the camera generates. Only after the case has been closed (and the air has been trapped) the air will heat up from the camera. No moisture is added. In such a scenario, increased temperature will decrease the relative humidity of the air, in other words the air will become warmer and drier, which will increase its capability to evaporate any potential water drops. This is also why AC'd air is drier: cooling down the air will make a lot of the water vapour condensate, so after it warms back up to the temperature it had before there's less moisture in the air (lower relative humidity) than it had before. Warm it up even more and it becomes even drier, which is why I'm pretty sure that a camera generating a lot of heat is actually beneficial towards fogging issues.

 

[mattpatton]

I went to the auto store down the street and got a double pack of RainEx. One pack was RainEx original, and the other was "RainEx Anti-Fog" for the inside of car windshields. We used the Mako flat lense, treated the inside with the anti-fog and the outside with the original. Worked like a charm! No fogging on a 1-hour long dive with the Hero2 in 62 degree water.

Video for reference.

 

[rha600]

Heading to Roatan next week and my buddy and I both have Go Pro Hero 2 and the flat port with red filters but we have been told there is a fogging problem. I am at a loss to explain this because the case is so tiny AND if one used the same precautions i.e. not opening the case in the boat but only in an air conditioned room...why would it fog? If so what are some fixes?

There is your problem.

I do "regular" photography and anytime you take a camera of any kind from a cool air conditioned room out into a hot humid environment outside it's going to fog.

I would suggest, before heading out, set the camera, with the case open outside and let it warm up so that both are equal to the temperature of the outside. If you want, you can probably bring it inside just before closing it up to get some lower humid air inside but honestly, I wouldn't bother.

I've done it this way with everything from my DSLRs taking photos on land to my still cameras with underwater cases and I never have a problem with fogging when doing it that way. If I forget and take the camera from the cool air conditioned area, straight outside I get fog 100% of the time.