I use aircon to avoid fog

This is my spin on avoiding fog/condensation on the inside of your housing. Please let me know if you think im confused.

I believe, despite what many say, that assembling your gear in an air conditioned environment is a good option.

As far as i know condensation is created when air cools. Cool air hold less water then warm air. This is why dew happens of an evening.

So... if you get your gear together in aircon(in temps lower then those expected in the water) the air should only warm. As the air gets warmer it will only get dryer. no fog!

sorry if this has been said before....new to the forum.

Cheers

on top of that, air conditioners usually dry the air which i think also helps.

Air conditioning has always worked for me. It's not the cool temperature of the air but the lack of humidity in the air that you are interested in when assembling your camera and housing.

bah.. a teabag or two works cracking (i do find PG pyramids the best!)!! better than the other sachets!! And i have never been lucky enough to stay in those nice gucci places with aircon to find out! hehe.. no bitterness!

a teabag or two works cracking

And just think -- free ice tea if you happen to flood your housing during a cold water dive!

The way i did it, when i had a poly housing, was use the massive supply of cold, dry air that u have strapped to ur back!

If say u have to change a battery or card between dives and are in a humid environment, on a boat, get a tank slightly hissing that cold dry air and try if u can to hand seal the housing around it. Hard to get the air to go into the housing but better than nothing and worked for me!

Olly

What do You think about the silica gel?

What do You think about the silica gel?

I have been keeping a couple of pouches in the bottom of my housing and I have had not any problems...

What is condensation:

The two - for Photographers - important parameters regarding condensation/fogging are:

1° percentage of humidity in the air inside the housing/camera

2° temperature difference between the inside and the outside the housing

As more dry the air is, as wider the temperature difference can be before condensation/fogging will occur

So:

Eliminating the temperature difference will reduce condensation

Filling the housing (and camera body) with dry air will reduce condensation

Who to?

1° transport and store your camera in a hard/soft cooler, with the camera wrapped in a thick, fluffy towel to protect her from sunlight/heat

2° You may fill the hard cooler with seawater and change this frequently to have it the same temp as the sea

3° load and close your housing inside a airconditioned but not cold room the evening before and/or use dry air from a tank

4. having stiff temp drops below the termocline(s) you have to work with dry air and maybe additionally silica gel bags / moisture munchers

What NOT to do:

1° open the housing on the boat if not absolutely necessary (f.e. no card, battery empty, wrong lens, etc.)

2. leave the camera in a boat rinse tank, she will bang around, hit other cameras and flood sooner or later

3. have the camera banging around your personal cooler/bucket, try to block the camera that she can't move

4° trap edge/border of the silicia gel bag between the housing/o-ring, triple check before you close

5° have the moisture muncher tubes rolling around the housing, they may roll on the wrong place and block a button/function

6° loading the camera with sweaty/wet/humid hands, doing it in a a/c'd room should avoid that

Moisture munchers / silicia gel bags

I personally don't find them very helpful and don't use them anymore. They may work under special circumstances like diving in very cold water,

termocline issues and strong variations of temperature.

I use (and respect) my rules above and never have problems with fogging/condensation.

Chris

Good writeup Chris. Essentially, if you want to learn more about this, learn more about DEWPOINT of air and how it is affected by temperature. Any time you "hit" the dewpoint of the air in your housing, it will go from water vapor to liquid water aka condensation.

Cheers

James

Thanks for your credits James! :-)

Here a articel about the dewpoint: http://en.wikipedia.org/wiki/Dew_point

Chris

Just read this thread.. I'm not to up on the physics of the whole thing, but I can speak from experience. I quite regularly do shoots in heated swimming pools in an outdoor environment, i.e air temperature (and so inside the camera housing temperature) can be low, 6-10 degrees celcius on occasion, and the water temperature is high'ish (I think both pools are about 30 degress C). Condensation will still occur if you don't do something about the humidity within the housing, i.e. being a lower temperature then the water is not going to protect you.

I get around this by blowing hot air into the housing and onto the glass of the dome port, this drys out the air, and also brings the internal temperature of the housing and the glass up to similar temperature to the pool, to avoid the temperature difference.

Just read this thread.. I'm not to up on the physics of the whole thing, but I can speak from experience. I quite regularly do shoots in heated swimming pools in an outdoor environment, i.e air temperature (and so inside the camera housing temperature) can be low, 6-10 degrees celcius on occasion, and the water temperature is high'ish (I think both pools are about 30 degress C). Condensation will still occur if you don't do something about the humidity within the housing, i.e. being a lower temperature then the water is not going to protect you.

 

I get around this by blowing hot air into the housing and onto the glass of the dome port, this drys out the air, and also brings the internal temperature of the housing and the glass up to similar temperature to the pool, to avoid the temperature difference.

I agree about the hot air. I have had good results by gently blowing warm air into the housing using a hair dryer on a low setting.

Bottom line: no water vapor, no condensation. Air conditioners dehydrate air. Scuba tank air is dry air.

NEVER take a bare camera from an A/C room outside when in the humid tropics. Always put the camera into the housing inside the room, or wrap it in a plastic bag and keep it there until the camera warms to ambient temperature. If you fog your camera, there will be water trapped in nooks and crannies that can cause condensation later. If you ever fog your camera, keep it inside an A/C room for a least several hours, use the hair dryer to gently warm the camera, and keep your fingers crossed.

Pieces of women's panty liners in the housing can save you from a minor leak! The modified cellulose absorbs many times its weight in water.

If you use silica gel packs or the like, you must regenerate them before you use them! They don't keep working forever.