How to avoid condensation inside housing in hot humid weather?

Well, I'm not expert, but I've used EWA Marine bag for a compact camera while kayaking. I remember that for proper use these bags must be pumped with some air via small valve (of pneumatic matress resemblance). By the way, that single element was the main weakness of the bag - easy to open accidentally.  Some extra protection needed.

What is important here: I've discovered qucikly that blowing air by yourself into the bag gives a lot of condensation if you don't use dessicator inside. So I've bought rubber ball for blowing dust and used it as a small pump. It worked, but in your case I would probably use both it AND dessicator. Note, the ball must be relatively big one or have an inlet one-direction valve in the rear end to work effectively. Your soft-casing is bigger than mine was...

-J.

A/C also acts as a dehumidifier.  I long used to close up my gopros and my slr rigs in the A/C room, and never expose to the 100% humidity outside.  It worked fine, though became a hassle.  On the liveaboard boats, not practical, and I found no bad came of doing it all on the camera table.   It had the humidity, but not the temp shift you warn of.

Anilao, earlier this year, was land based.   Every morning and every lunch, everyone did their thing in the 20 person station camera room, then took it out to the boats.  Not a concern.   But you don't want to open it outside, just after leaving the cooled room.

PHXAZCRAIG wrote:

That makes sense - seal it in A/C, then get it up to temperature before diving.

By the way, I almost booked a week in Anilao this December. Felt nervous about both water temps and being in the Phillipines, but ultimately had to hold off for health reasons. Would love to know more about it. I'm trying to get in another 56 dives between now and July, probably in the Caribbean (for affordability).

Anilao is a pretty cheap place to crank out 30-36 dives on a 10 day booking.  (4 per day)  I think the resort part was ~2500 and the airfare around 1400RT, but that was EVA's premium economy.   Straight up coach would have been under 1000.

My wife still logs, so I could find the temp range in May, but most of the time it was marginally necessary to wear the wetsuits for warmth.  Some spots definitely cooler with some unexpected thermoclines.  But bigger reason you need to wetsuit up is you're often planted on the sand next to the target, and there's definitely jelly stuff in the streaming current.  Ankles and wrists get it.

I thought bay waters meant trivial diving, but it's really tidal flows.   About 1 dive each day could have strong to mildly ridiculous current, and not in a predictable way.  That translated into moderately advanced diving conditions.   Not the best place for a new macro diver.  And there can be a fatigue factor with 9 days of it.   Downside to land based is the time you spend on the little boats going out and back twice a day.   But the subject density is ridiculous.

Anilao is pretty isolated from the nonsense with the new regime.  2-3 hour ride from the airport.  The resorts are all built along a steep slope - just ten years ago you had to take a boat to get to the resorts.  Generally an all inclusive approach - too hard to get to anything else.

I was with Blue Water, who uses Crystal Blue.  They have an excellent resident pro.  The dive boats take 3-4 divers plus the guide, though there can obviously be multiple boats from the various resorts at a given site.  But rarely a crowd.

Cayman Aggressor would be my next choice for high dive density.   ~3k for a week charter with 27 dive slots.  Never gets old floating along Bloody Bay Wall.

Ha!

ive felt with this issue for 20 years and heard many different solutions. None of which seem to work reliably with plastic housings.

the best answer is never take your housing into the air conditioning. Leave your camera outside and assemble outside. Thus seems to work best. Nothing seems to work all the time.

the best solution is to make sure your housing is metal and glass.

Allen Murray wrote:

Yes, the A/C dehumidifies first, then cools. I don't want the camera and inside of the case cold necessarily, I want the air inside the case to have a very low moisture content.

Did you happen to know thoise two depend on each other. It's very, very basic physics.

Master of the Universe wrote:

Allen Murray wrote:

Yes, the A/C dehumidifies first, then cools. I don't want the camera and inside of the case cold necessarily, I want the air inside the case to have a very low moisture content.

Did you happen to know thoise two depend on each other. It's very, very basic physics.

Are you saying hot and dry air is impossible?

Barmaglot_07 wrote:

Julian500 wrote:

Are you saying hot and dry air is impossible?

In areas where one would be using an underwater camera housing, hot and dry air, while not impossible, is highly unlikely.

this thread seems at risk of dick waving, but

close housing in A/C'd room.   Take housing to back to dive boat.

In pretty short order, you have a housing with hot dry air.

Barmaglot_07 wrote:

Not what I meant and you know it but....

Frankly I have no idea what the point of your or Master's posts were.   They don't help the OP's query very much.

I don't know how much more prevalent this problem is with plastic.   I have taken both the AC only and outdoor only routes.   The only time I've been bit is when I try to take the camera out of my cabin to get top side pics.

Condensation in underwater cameras housings.

There are many posts on this subject with only bits of information that don't always seems to add up or is just a bit bitty. So I hope this helps.. This generally applies If the housing "does not" have "dry" air inside, and has a higher humidity level, i.e particularly a issue in the tropics.

POLY carbonate housings often have more front port glass fogging issues than aluminium housings, the poly case doesn't condense much moisture onto its inner surfaces as it a poor conductor of heat, the inner surface inside the housing therefore remains warmer and any moisture that is present inside, doesn't readily condense on the housing walls, resulting in more vapour staying air borne longer which finds it way to the glass port. The glass port generally being the coldest surface, the moisture condenses, similar to your windows at home.

A METAL housing inner surface temperature is normally cooler as the case conducts heat way into the cold water, and the inner surface temperature is therefore much closer to the cooler water temperature, (i.e water cooled) then acts like a "moisture sponge" so to speak, moisture condenses on the housing sides, this may not be visible, resulting in less moisture being "air borne", (air is now a bit dryer) resulting in less moisture vapour reaching the glass port window, therefore less fogging issues. This process has a similar effect as putting silica gel packs inside the housing to help soak up vapour.

In either housing type, a hot camera, heating up the inside of the housing can in some circumstances re-evaporate some moisture, that is (if any) off the case inner sides to some degree.

So if a glass port is clear with the camera off, Turning on the camera in some circumstances can cause fogging to occur.

As you dive deeper the water temperature often cools and you can find fogging occurs more at depth and can also clear nearer the surface.

The answer to all these issues is to have dry air inside your housing at all times.

Ways to achieve this is to always assemble camera in a air conditioned room. Carefully blow dive cylinder dry air into housing as you close it, or put open prepared camera housing in large plastic bag and fill with dive cylinder dry air, and close it whilst in the dry atmosphere. Least reliable is using silica gel packs inside the housing.

If you would like to know about the physics, google "dew point" and "relative humidity".

To help you with this, remember these following points..
Water condenses on a glass port when the RH reaches 100% at that point.
An air conditioned room may have a RH of about 40%.When vapour condenses on a glass surface, it has reached its dew point temperature.
Dew point of dry dive air is in the minus figures. i.e Extremely dry.

As an example: An aircon room at 25 degrees, with RH=40% has a dew point of 10 degrees. Seal up the camera and trap this air inside, and condensation will not occur on the port until the water temp reaches 10 degrees. This is always going to stop fogging in the above example.

Andy Willett

this was a 3 year old thread revived.

With the ILCs, I don't think it comes up-  too much air to heat.   And since nearly all of us have moved to vacuum systems, less air and moisture anyway.