On Friday, February 22, 2002 1:02 AM, Crusty Russ wrote:

(snip)
>  The primary difference between
> analog (film) and digital cameras, with regards to fogging, is heat.
> The digi cameras produce a tremendous amount of heat.  As the
> hi-capacity batteries discharge while powering the internal electronics,
> storage media, and particularly the screen!

Mate!  I'd never even considered that!   :-)

(snip)
> I use the anti lens fog that came with both my cameras along with a thin
> folded piece of a feminine napkin cut to fit into the bottom of the
> housing.  The highly absorbent napkin will often control mini floods and
> I believe help reduce the fog problem.

That's a great idea and one that I'll try out tomorrow.

>Silica gel packets are
> problematic in that they are minimally effective when exposed to a high
> humidity marine environment.  I recall reading about techniques to dry
> out the gel but none of those proved practical in most tropical
> locations or while on a boat.  In any case, I recall that the packets
> become saturated almost as quickly as they are dried out when exposed to
> high humidity, probably rendering them ineffective even by their brief
> exposure to the environment when installing them in a camera.

And I'll forget the idea of silica gel!  :-)

> I claim no expertise in this matter, only sharing my efforts as one of
> the 'million monkeys at the keyboard' attempting to hammer out a
> Shakespearean folio.  :-)  However, I think a key component to the fog
> problem that must be accounted for in any solution is the heat produced
> by a digi camera's normal operation.

External fogging of the lens has always been a problem - especially when
going from air-conditioned comfort into a warm, humid atmosphere.  But it's
one that's easily resolved.  And because the inner eye of the lens is within
the body of the housing and not exposed directly to temperature
fluctuations, it's never seemed to be an issue with conventional cameras on
land - and never a problem U/W.

But it's been bloody frustrating over the past couple of weeks when - not
having paid enough attention to the proper application of the de-fogging
solution, (as per the housing's instructions!) - during the latter part of
the dive, I've noticed a thin film of fog appearing on portions of the
inside of the housing lens.  (The dreaded "F" word was my first thought!)
:-)

Thanks for that information, Crusty.  It's encouraged me to pay more
attention to the housing's accompanying instructions; provided me with some
ideas for reducing moisture build-up; and removed the fear that I had that
the housing was providing a less than perfect seal!  :-)

Strike