Subject matter happens to be one of my favourite "croon" songs;
especially by Sinatra.

On Fri, 22 Feb 2002 06:57:18 +1100, David Strike
<[log in to unmask]> wrote:

to my earlier response:

> > Just because this housing is digital doesn't mean it's not a housing
> > just like any other. Your former Nik V is a housing (forgive me if I'm
> > trying to teach my proverbial grandmother to suck eggs) but I've yet
> > to meet an u/w photog who has need of defogger for their
> > housing/waterproof (??? <BWG>) camera.
>
> Possibly because the glass covering the lens of the Nik V is a sealed unit
> with no moisture present inside it - as can be the case with an open
> housing.

Lenses are lenses and, I rather suspect, *all* (at least self
respecting) lenses are sealed otherwise above water users would have
*huge* problems virtually every day, I described one such example in
my last post. Indeed the tolerances within lens arrays would make
atmospheric disturbance highly undesirable.

Now, if you use a housed lens it is "protected" by the camera. In your
case I suspect that it is a fixed (rather than exchangeable) lens and
therefore protected by the camera even more so. Does this make sense?
I hasten to say that my point is that my description might be suspect.

I'm assuming that your "fog problem" is either on the surface of the
front port of your lens or the surface of the interior of your housing
port, or both. I would not expect it to occur at the other end of your
lens where it meets the camera body however, if it does, you really do
have a serious problem. All the evidence points away from that, thankfully.

I still consider that proper management technique of temperature,
ambient vis a vis subsurface, should deal with the problem.

As a side note: I consider that a photograph depends not on the box
(camera). It depends on the tolerances of the glass in the lens and,
in our case, the tolerances of the glass of the housing port, and then
on the intolerances of the idiot pressing the shutter button. :-7

That said, I am MOST, ABSOLUTELY, HUGELY, reluctant to smear bits of
grease (of whatever persuasion) on any of these glass surfaces for
those very reasons. Well, at least the first two of them anyway. ;)

Incidentally, if you decide to take your camera system into the
welcome confines of the airconditioning in a hermetically sealed box,
having done what you want to it in ambient temperature, and then
return it to that ambient temperature the next morning (or whenever),
why, the dreaded "Fogging Factor" does not make an appearance.

Provided the Tupperware box did not get compromised.

Provided the ambient temp at re-emergence of the camera system is not
hugely different to what it was.

HOWEVER, Crusty's post:

> This discussion regarding fog control in housings has been most
> interesting!  Having wrestled with the problem on several U/W digital
> cameras there is a small but important fact that has a significant
> impact on anti fog cause and control.  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!
(snip)

throws a large wrench into the works of my thinking. I have never
experienced a digital unnawata (apart from Roger's digital video which
might not present the same problems and of which he has never
complained). Well, in this regard anyway. ;)

That's a new, and most intriguing, one to me and I stand, well, at the
very least "properly advised". It's also one that has not come up (to
my knowledge) on the specialist lists, at least the major one of which
I know that Crusty is a member (albeit rare contributor, regrettably).
Digital photography is a hot topic there, much discussed, and this
does not appear to have surfaced.

I'm not in the least, here, saying that Crusty is wrong, far from it.

Crusty, perhaps you might like to voice that question there? It's not
my place to really, I don't (yet) own one and obviously different
cameras have different battery temperatures, which opens up another
can of worms for those interested in this.

My head, yet again, hurts already. :)

Cheers,

Christian