Anti fog on housing lens reducing fog

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Bubbletrubble

Agree with you on the "Don't use defog" inside the housing - but I've found when putting a camera in and closing housing in an aircon cooled room (or car) - and then heading into warmer humid air or water, it would fog up the inside of the housing - subsequently I now make sure the camera/open housing is at least allowed to warm up to ambient before closing housing.

I have had similar experiences as Wantonmien. If you keep the camera in AC and open and close it there, you should be fine.

You get fogging issues with cameras if the air inside the housing is warmer than the water you dive in. So if you are diving in 80 degree water and it is 94 degrees outside and you open the camera and dive. The air in the camera will drop down to 80 degrees. Cool air does not hold as much moisture and the moisture in the air condenses on the housing creating "fog".

If you want to open the camera between dives, the only option you have that will work is using dessicant packets.
@PatW: I agree with your reasoning, although I believe you misunderstood what Wantonmien was saying. Wantonmien said that when he assembles his camera + UW housing in an A/C room and then splashes into warm water (77°F or warmer) then he experiences condensation inside the case. In his example, the temperature inside the case is colder than the ambient temp outside the case.
@Wantonmien: You know, I don't normally have a problem trapping air into the UW housing that's colder than the temperature of the water. Bottom temps where I dive are usually in the 50-65°F range. Perhaps this is a case of different practices for different diving conditions.

As PatW stated, in order for condensation to occur inside an UW housing, there needs to be a source of water vapor (humid air inside housing) and a temperature gradient (between air inside housing and water/air outside of housing). In general terms, warmer air has a greater capacity to support water vapor than colder air.
Scenario #1: When the skin of a container is cooled to a temperature below that of the dew point of air inside the container, condensation occurs on the inside of the walls of the container.
Scenario #2: Alternatively, if something inside the container (camera) heats up and there's cold air with some water vapor surrounding the camera inside the UW housing, condensation can occur on the camera itself. It can look like the camera is "sweating."

OK, so let's see why assembling the camera + UW housing in an A/C room works for me. Cold, dehumidified air = low water vapor inside housing. Since water bottom temps are in the 50s-60s (°F), having that cold A/C air inside the housing decreases the temperature gradient between outside and inside the housing. In this way, I avoid the condensation that occurs in Scenario #1.

Without doing any tests, I can't be sure why assembling the camera + UW housing in an A/C room didn't work for you. After all, cold, dehumidified air = low water vapor inside housing. However, a significant difference is that water bottom temps are higher than 77°F (25°C). I suppose that it's possible that condensation forms on the camera itself (inside the housing) as it heats up - Scenario #2. What happens if you assemble the camera + UW housing in an A/C room and then don't turn on the camera at all? I suspect that you might not see condensation on the camera or on the inside walls of the UW housing. I'd be really interested in finding out what happens. In any case, decreasing the temperature gradient between outside the case and inside the case is a good thing. Eliminate the temp gradient and you eliminate condensation problems.

Let me know if you can do the above experiment. I'm pretty curious about the results.
 
Another factor to toss into the mixture is to keep the housing out of the sun and tropical heat.

Direct sunlight for only a few minutes is cooking that camera in a sealed housing.
Put it in the ocean after that and you may get condensation.

If possible keep the camera/housing in a beverage cooler as they are insulated and keep the heat out to a good degree.
 
Another factor to toss into the mixture is to keep the housing out of the sun and tropical heat.

Direct sunlight for only a few minutes is cooking that camera in a sealed housing.
Put it in the ocean after that and you may get condensation.

If possible keep the camera/housing in a beverage cooler as they are insulated and keep the heat out to a good degree.

On our boat they have a big like plastic tub to float your cameras in..

And thanks everyone for your help!!! :D
 
I concur with the silica packets, but I usually don't pay for them. The wife has quite the shoe fetish and I just take the little ones that come in the shoe boxes. They work great, and they're free...sort of!
 
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I concur with the silica packets, but I usually don't pay for them. The wife has quite the shoe fetish and I just take the little ones that come in the shoe boxes. They work great, and they're free...sort of!

Wait you can use the ones in a shoe box?? cause my mom has tons of those!!! yes i love free stuff!!!!!! xD :D
 
I've been using them for years, and they work fine for me. 1 or 2 in the corners of the housing seem to work like a charm.
 
I've been using them for years, and they work fine for me. 1 or 2 in the corners of the housing seem to work like a charm.

Thanks i will try it!!
 
Wantonmien[/B]: You know, I don't normally have a problem trapping air into the UW housing that's colder than the temperature of the water. Bottom temps where I dive are usually in the 50-65°F range. Perhaps this is a case of different practices for different diving conditions.

Bubbletrouble, for sure we can blame it on differences in environmental conditions and humidity, as for sure in places such as Ozzie GBR, Philippines islands & Taiwan I've walked out of Air conditoned cold rooms, and sunglasses and camera lens have steamed up instantly - until they have warmed up to ambient temps, ditto with camera lens ~ moisture source of course being from the very humid air.

First time I ever had inner of closed housing (with camera inside but not switched on) fogging up was on the Ozzie GBR, and it wasn't until a couple of months later in Philippines that a DM pointed out to me that before placing air con 'cold' camera in air con 'cold' housing - it was better to get both into the ambient temperatures and leave the housing open (with open sides facing up into sun) for a few minutes, and leave camera to warm up at same time. Since I have followed that advise, I've not had fogging inside the housing.

Temperatures in locations I had 'fogging' inside housing were typically -

Air Con room/car - 22~25°C (71~77°F)
Ambient Air 30~38°C (85~100°F)
Water Temps typically - 28~30°C (82~85°F)
Humidity ... Can only say very high, probably approaching 100 %

PS - I think I did the degrees °C to °F right - in which case I shudder to think of the low temps you dive in 10~18°C (50-65°F) - :shakehead: that to me would be like an ice bath !!

Cheers
 
I found this site silicagelpacketsforcoins.com. Has anybody used them before. You can get 50 packs for about $10 with free shipping. Looks like a pretty good deal.
 
I bought some silica packets, they are in small plastic bags instead of paper bags, do I need to cut the plastic bags to allow the moisture to be absorbed by the silica or just leave it as it is?
 
https://www.shearwater.com/products/swift/

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