I'm preparing to photograph in ~50F water (10C) and worried about my housing fogging. What steps should I take to prevent or minimize it?

 

The humidity where I’m diving is 94% and the dew point is 50F (10C). I can’t do much about the humidity where I will be staying (hardly have electricity), but I could leave my housing open in the car the night before so it stays cold and then close it up in the morning. Any other suggestions for preventing fogging? Silica gel packets are an option too.

 

Side Note: While I can put my housing together the night before, I will have to open it once or two a day to replace camera batteries.

 

 

Edited October 7, 20241 yr by brightnight

Chris is a whizz at humidity/fogging issues and I'm sure will chip-in.

 

What's the air temperature?

 

Based on my own experience, I reckon leaving the housing closed up (not open) overnight in the normal ambient temperature is usually the way to go. 

During a typical dive I expect the air temperature to be 40-50F (4.4-10C) but I will be in the water (shallow) as long as possible, from morning until dark. 

 

At the coldest the air temp will be 30F (-1 C) at night and 52 F (10C) during the day.

Seal it in the AC car when possible. Maybe have someone blow in dry tank air with a nozzle as you seal it if fogging becomes a problem. 

 

I dive in similar conditions often (50f water and humid boat cabin when i seal) and never have trouble with fogging. I do vacuum seal the housing which may also help.

24 minutes ago, brightnight said:

I expect the air temperature to be 40-50F (4.4-10C) but I will be in the water (shallow) as long as possible, from morning until dark. 

 

Woah, you are one tough, dude! Good luck with that. I had to put a jumper on to even read that.

 

I'm off to the Red Sea fairly soon: 28C degrees.... 😎 

Here are some tips to reduce the chance of fogging. The first two are generally the most significant:

 

1. If possible, seal cool, dry air inside the housing (such as from an air conditioner).

2. If you have a vacuum system, the more air you vacuum out, the lower the chance of fogging.

3. When opening up the housing to change batteries, make sure no drops of water fall in. 

4. When the housing is out of the water, don't let it heat up in the sun.

5. Silica gel packets can help but in my experience are less significant than some of these other things.

 

Since it sounds like the air temperature will never be much warmer than the water temperature, I doubt you will have fogging issues if you follow a few of these tips. The biggest risk of fogging comes when the housing is filled with humid air that is significantly warmer than the water. 

Edited October 8, 20241 yr by Isaac Szabo

Air from a scuba tank is very dry and if you blow some in as you seal up it will help. Have a clean lint free microfibre cloth to wipe drops from the o-ring when you open it to stop them getting in the housing.  Closing it up in the coldest air will have the lowest moisture content.  If the air temperature is less than the water temperature the housing won't fog as long as long as no liquid water is trapped.  The key is that cold air holds less moisture than warmer air before it starts to condense.

 

Leaving the housing in the sun only causes a problem if there are liquid water drops inside - trapped by the o-ring.

On 10/11/2024 at 2:13 AM, Chris Ross said:

Leaving the housing in the sun only causes a problem if there are liquid water drops inside - trapped by the o-ring.

 

I have seen it cause fogging in other circumstances. Most recently with Nauticam optics like the WWL-1 and EMWL. After they have heated up in the sun they can develop internal fogging when you take them into cold water. It can take quite a while for the fogging to clear (30 minutes or more). 

 

I think I have also experienced this kind of fogging with regular wide angle lenses and dome ports, but it has been quite a while ago, so the details are not clear in my memory. 

1 hour ago, Isaac Szabo said:

 

I have seen it cause fogging in other circumstances. Most recently with Nauticam optics like the WWL-1 and EMWL. After they have heated up in the sun they can develop internal fogging when you take them into cold water. It can take quite a while for the fogging to clear (30 minutes or more). 

 

I think I have also experienced this kind of fogging with regular wide angle lenses and dome ports, but it has been quite a while ago, so the details are not clear in my memory. 

Yes but this can only happen if there is water inside to vapourise.  Heat causes water to evaporate, not condense.  If it was just humidity then you would expect fogging when it was already cold.

40 minutes ago, Chris Ross said:

Yes but this can only happen if there is water inside to vapourise.  Heat causes water to evaporate, not condense.  If it was just humidity then you would expect fogging when it was already cold.

 

Yeah Chris I don't know exactly why this happens. I'm just relaying that it has happened to me a couple times and to one or two other people I know. Sealed Nauticam optics, heated up in the sun, fogged inside when taken into cold water. Same Nauticam optics have not fogged if kept covered/shaded from the sun before taken into cold water.