On Fri, 22 Feb 2002 10:59:23 -0500, Timothy Doty
<[log in to unmask]> wrote:
Subject:

Christian Gerzner wrote:

> > > 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)

Actually I didn't, *I* learnt from that, Crusty wrote it. :)
(snip)

> Hi all!  Well we all seem to agree heat is a problem, but how to control
> it!  Go back to you Open Water class and thing of your camera housing as an
> exposure suit for your camera.  Like a dry suit it keeps your camera dry,
> and warm.  Some UW housings insulate better than other(a bad thing).  I had
> opportunity to talk to a guy that took his new digital camera to the
> Arctics and in 32 degree water his camera would shut down in the middle of
> a dive because it would overheat.  He showed me some of the pics from the
> trip and if you looked at the pics in the order they where taken then you
> could see it overheat as the pics became distorted.  This was a few years
> ago when UW digital camera where a new thing and housings just weren't up
> to par, still...  Keeping the camera off when it doesn't need to be on,
> especially on the boat should help.  If your on a boat between dives turn
> the camera off and let it soak in the camera bucket.  If your more skilled
> than I and don't need the LCD to line up a pic you can turn that off too(as
> someone already mentioned).  Turn off the flash and get an external flash.
> Only use as large a battery as needed, a larger capacity battery contains
> more energy, therefore more heat potential.  Diving in cold water help
> too...

I've had a little think about all of this, about what happens to the
above water digitals that I've been using for, oh, three or so years
now. These are "corporate" cameras and therefore at the high end of
the market. The first one was capable of reproducing at least an A6
size image in print (4 x 6" approx) while the brand spanking new one
can easily do the same for an A4 image (8.26 x 11.7"). This camera
requires prodigious amounts of memory to do this. No it's not the same
as on the web/your monitor, that requires just 72 dots per inch (more
correctly pixels per inch) whereas a *printed* image requires a
minimum of 300 dpi at the size that the image is to be printed at.

Phew, thereby endeth the lesson. :7

Both the corporate cameras (thankfully) are capable of using good old
AA batteries, available everywhere in whatever permutation you want
(alkaline, NiCad, NiMh, whatever) and I personally strongly believe
that this is a decided advantage. If the camera you're considering
requires some fancy battery, I'd look elsewhere. There are a *lot* of
pro-sumer cameras out there now (admittedly few come with housings) so
an easy, simple, battery system should not be a big ask.

So to the use of these things unnawata: I'd guess that Crusty's
example is that his shipmate was using an acrylic housing a la Ikelite
(they make great gear and their service is nothing less than
legendary) vis a vis Crusty's aluminium housing which, if I read the
inference correctly, acted like a heat sink.

As he also correctly says the digitals require prodigious amounts of
power which is as much evident above water as below. So, I never use
the back screen except on command (*my* distinct advantage is that
both "mine" are true SLR's, I can see what I'm gonna get "through the
lens") and, in the case of "my" Olympus cameras, they go into "sleep
mode" after, oh, thirty seconds? Probably less actually and that is
sometimes frustrating such that if I'm working in a dynamic
environment I have to give consideration to this.

But it's useful unnawata, there the "dynamic environment" happens when
you come across, say, a bunch of clownfish in an anemone, when you'll
want to shoot as quickly as you can, previously mostly restricted by
the speed at which your strobe/s can recharge. Regardless, that's a
given with strobe/s on digital housings.

Today? It's all gone pear shaped. Today I believe that only Ikelite
makes a dedicated digital u/w strobe. Even then, it may not work on
some systems. Of course, all of this will change "real soon now"; I
can't imagine that the likes of subtronic are not hard at work
adapting their systems.

Then Strike wrote:

> So far the only setting that I've changed on the menu is the flash - and
> I've moved that to low.  But I think that I may start experimenting next
> with the ISO settings and gradually work my way up to 400 just to see what
> difference that makes?  (At least with digital the cost of film is
> eliminated!)  :-)

You're using (I believe?) the built-in flash which, on *any* u/w
camera system, is problematical in the extreme. It's too, much too,
close to the lens. It creates backscatter big-time and you can't avoid
that with such a close, and close up, flash.

Yep, the digitals have the ability to change their ISO setting and
both "mine" have this but, to the little that I have experimented with
this above water (and I have a digital, dedicated, strobe, $AU1400,
Phew) for these cameras and don't use the built-in one at all this seems
to make precious little difference. FWTIW, I really don't know.
Regardless, u/w you're going to lose those colours without artificial
light, the laws of light don't vary just because you're shooting
digital. :(

What does, or in my perception seems to, vary, is that super-saturated
colours of the likes of Fuji Velvia 50 cannot be replicated (yet) and
(this is a very positive "and") the extreme grain of those same films
is not required because, but of course, we are now talking in pixels,
and only pixels. So, does it follow that Velvia style supersaturation
is only the province of (still) extremely expensive digitals such as
the top-of-the-line Canons, Kyoceras, Nikons, Olympics etc which are
capable of storing so many more "pixels per inch" than the more
consumer orientated models?

I rather think that jury is well and truly out to lunch and likely to
remain so for the significant future. :)

Incidentally, proper management of re-chargeable batteries is getting
increasingly important and I can't emphasise that enough. Your
common-or-garden battery charger available from the likes of Dick
Smith, Radio Shack etc simply is not good enough and, before anyone
tells me that NiMh's do not carry a memory, no, that is technically
incorrect. Even the charger supplied with "my" you-beaut Olympus is a
"dumb" charger and if you are (and I am, in this case at least) as
dumb then you need something better such as a, well, non-dumb charger.

My choice here (more importantly that of the U/W Photography mob) is Ansmann:

http://www.nexusamerica.com/main.html (me mate Woody Mayhew in the States)
http://www.ansmann.de/ansmann1.html (Germany, can't remember whether
there's an English page)

For the Aussies amongst us, yes, there's an Aussie representative.
I've been in touch with them and they're, uhhhhh, not exactly
efficient? Forthcoming? Their web page seriously, errrmmmm, sucks?
Can't remember who they are but if you must, I'll find out again.

Cheers,

Christian