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Phil Horbury

Any help would be much appreciated!

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Hi Guys,

 

My name's Phil and I'm a recently started videographer working in The Maldives in North Male Atoll. I use a Sony HDR-HC5 with an Ikelite housing, Epoque 67mm WA and Adobe Premier for all Post-Pro. All going well so far but in the last few weeks I've noticed that no matter what pre and post dive prep I go through (O-Ring maintenance, sorting my housing properly, cleaning, ensuring a bone-dry housing etc etc).........

 

After maybe 25 minutes on a dive I am getting a small patch of fog (condensation, I would presume?) on the inner lense of the housing - not good at all as I'm sure everone would agree. The thing is, I'm racking my brain, trying everything but no joy. If I don't secure all the footage I need within 25 mins - well, it's curtains for the dive.

 

I'm pretty new to the position and am sure there's some "schoolboy error" I'm committing - can someone run through the things that are absolute neccessities in terms of kit prep and what are the no-no's too? I'm sure there's something I'm either not doing that I should, or the reverse! If you could give me some advice on cleaning and stowing, or just some tricks to stop this I'd be so pleased.

 

Thanks, from a desperate rookie........!!

Phil Horbury

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Hi Phil,

 

The key to a lot of this is assembling the rig (sealing the housing) in an environment that is dry. Cold air has a lower saturation vapor pressure and will therefore generally be drier than warm air. If you seal cool dry air in the housing, then warm it up, you will have no problems with fogging as the air will will be absorbing all the humidity it can (as a matter of fact, as the temperature increases, the relative humidity will drop if no additional water vapor is added). If you seal the housing in a warmer environment with slightly higher humidity, then as you cool it (without adding water vapor) the relative humidity inside begins to increase and as you approach the saturation pressure, the water vapor will begin to condense on the inside of the housing.

 

I only have a lil compact digicam setup, but did have some problems with fogging. Until recently I had managed to control fogging in it pretty well (recently I've been having problems with my WA conversion lens fogging up) through just silica gel packs and keeping the rig away from direct sunlight.

 

My current setup routine consists in sealing the housing in a the dryest environment I can find. Usually at home or in my office, the night before when it's cooler and as far away from the humidity as I can get. I've seen recomendations for asembling in an air conditioned house or car (so that the camera and all the air in the housing is cool and dry), but neither one is really an option for me. When I put the housing together, I also fill the empty space within the housing with as many silica gel packs as I can fit without stuffing them in. Up until the dive, I keep the rig in the coolest place I can find and out of direct sunlight.

 

As for my latest problem, with the WA lens foging up, it has only been occurring recently. I'm guessing because it's almost summer here and getting rather warm topside and the water in central Chile is still pretty cool (about 15 deg C). So I figure that the rig is warming up while on the boat and then when I get in the cool water, and the lens cools, the moisture condenses and fogs up the lens (usually after about 10 minutes or so - similar to what's happening to you taking into account the smaller volume of my setup). It was suggested to me (by another Wetpixel member) that I fill a small cooler with seawater from the dive site and leave my assembled rig in that for as long as I can before the dive in order for all the innerds of the rig to equalize to the temperature to the water. I haven't tried this yet, but it sounds reasonable. I even have a cooler with a small refrigeration unit that plugs into the 12V current provided by a cigarrete lighter on my boat. Next time out, I'm going to fill that with seawater, drop my rig in and plug it in during the ride out to the site.

 

I've even thought about leaving all the pieces (camera without battery & battery door open, WA lens, and open housing) in a ziploc bag or large tupperware with some large silica gel packs in my fridge overnight in order to purge all the water vapor from it before putting it all together.

 

Hope some of this helps at least give you some ideas to finding a solution that works for you. Good luck.

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Hi Phil,

 

I dive an Ike housed G9 and even with two silca gel packs the glass port can often fog. I have eliminated fogging now by flooding the housing with clean dry breathing gas. To do this I use either an 'air gun' attached to the inflator hose or when my dive kit isn't readily available an unused 0.4 litre AP Valves 'suicide bottle' and short length of hose.

 

HTH, Tim

Edited by Timmoranuk

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Phil,

 

The problem with plastic housings is that platics and glass have different temp coeffs. That leads to that the fog ends of exactly at the place you do want, the glass lens.

How can you get rid of this?

Either by getting very dry air into the Housing before closing it. This you can do either by closing the Housing in an Aircon environment. The other a bit trickier solution is to use the dry air of compressed air. Fill up a plastic bag with compressed air, out of the dive bottle. Then place the Housing inside the plastic bag and close it.

The second type of solution is to add something that sucks up the extra humidity, Silica Gel bags.

 

/Erik

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Or just get an aluminum housing. A much better conductor of heat. For condensation to occur you must also have a sufficient temperature differential inside/outside the housing. Temperature is equalized much faster with aluminum vs polycarbonate or acrylic, thus greatly reducing the chance of condensation.

Edited by jcclink

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That is true. Aluminium Housings have less visible problems.

Alu leads temp better than glass, therefore the condensation water does not end up on the glass.

Plastics is basically a thermal isolator and glass is better. This leads to that the condense water ends up on the glass.

 

/Erik

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Phil

 

I experienced a similar fogging problem that you described and my solution to lens fogging is to use a hair dryer set at the lowest warm setting to dry the camera, lens, and housing as I proceed to close the housing. I have an Ikelite housing for my Canon 5D camera and since using a hair dryer during closure of the housing with camera in it I have not had any fogging. I generally dive Bonaire, St. Lucia, etc. I also place a descant unit in the housing which generally lasts 4 to 5 days.

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