Underwater Experience with S40 and WP-DC300

[cesarini]

In absence of a dedicated topic on underwater usage of Canon cameras, I'd like to collect experiences with S40 and its waterproof case WP-DC300.
My major problem is fogging.
I mediterranean sea, below aroound 12 meters temperature of water drops down to 15-17 °C so causing fogging inside the case. I tried with antifogging liquid, but no info from Canon how to use it (Canon on its site suggest the use of silikagel bags).
I tried with air conditioning of car. It reduced the problem, but it still exists.
Does anyone knows other practical suggestions?

Finally few words about maximum depth of WP-DC300:
this week I have carried my camera at -36 in the first immersion and -39.2 meters in the second one.
In both cases - apart from fogging - I didn't experience any problems. Only at -39.2m I have noticed some little drops inside the case, but I don't know if it was due to fogging or due to initial leakage.

[FLL Diver]

I use the DC-WP700 case and I haven't had any problem with fogging as I don't run into the temperature swings you are experiencing. Here in Florida I haven't had more than a 16°F swing in air to bottom temp (8-9°C), with most in the 5-6°F range.

Looking at my log book I've even been fortunate enough to dive in water warmer than the air temperature during what passes for winter here. :)

However to help keep fogging to a minimum, I do keep the housing in a shaded water bucket until it's time to hit the water. I also do use a gel pack to keep moisture down inside the case.

Perhaps a slower descent may also help?

Marc

[cesarini]

Thanks for the suggestion of gel pack. Yesterday a friend of mine gave me one of these very rare objects and I'll try it in next dive.

I improved the situation with the following procedure:
1) I have applied on both camera optics and case glass (inside side) the antifogging liquid as uniformly as possible
2) I left the liquid to dry
3) during the tranfer to the diving center, I sealed the camera into the case with the air coming from the car air conditioning system.
...The result was no fog! :)
However I'm not yet completely satisfied of focusing level, which seems more degraded underwater than in air.
Did anyone experienced the same degradation?

p.s. I'd like to place a picture, but I do not know if it is possible and how to do it.