DV Info Net

DV Info Net (https://www.dvinfo.net/forum/)
-   Open DV Discussion (https://www.dvinfo.net/forum/open-dv-discussion/)
-   -   exposure question (https://www.dvinfo.net/forum/open-dv-discussion/15204-exposure-question.html)

Glen Irvine September 30th, 2003 09:24 PM

exposure question
 
Okay, here goes. The last couple of days I've had the fortune to
sit by the Birkenhead River and watch what is supposed to be one
the largest returns of sockeye salmon in the recordable past...
quite amazing really.

So I took the XL1-S down and decided I should do a little project.
I'm shooting glowing red salmon in a greenish water with a touch
of glare so I put on a polarizer. My zebra stripes are set to 100.
In order to get a good exposure on the fish themselves I
invariably end up with stripes showing on the river rocks and on
the fish's dorsal fins as they run up on the gravel. The days have
been very bright so the sun just glares of the fish skin. Problem is
that if I dial down to get rid of the stripes the exposure on the fish
under the water's surface is very dark.

I guess this is the general question....if the footage was
hypothetically for broadcast, how much damage have I done to
myself by allowing the exposure to exceed the max (i.e. the zebra
stripes to show ). Just as an aside, if I run the camera in
automatic mode the zebras show as well so the camera is
allowing overexposure. How would you camera guys with much
more experience than me handle this? Should I just go for
exposure on the fish and disregard the zebra stripes.....
find some sort of happy medium...or avoid the zebras stripes like
the plague and accept a slighly darker image of the fish. Any
comments would be greatly appreciated.

One last question.....the polarizer cuts down the glare and
seems to sharpen the image, but does it also increase the
contrast (i.e. difference between light and dark areas )?

As always, thanks for your help.

Glen Irvine ( peacefully sitting by the river watching the fish )

Jeff Donald October 1st, 2003 12:10 AM

Set the camera to -3db gain, use ND filters, Pol and wait for a cloudy day or shoot early in the morning or late in the afternoon. Never shoot mid-day. Light is too harsh and flat.

Glen Irvine October 1st, 2003 12:21 AM

Jeff,

Nice photos on your site. I set my camera gain at -3 as a matter
of course. I understand the comment about shooting early or late
or in cloudy weather, but the thing is, the fish absolutely light up
color wise in the more intense light (not to mention the beautiful
colors in the river). I'm trying not to sacrifice this; is it just a
compromise I'm forced to make?

Thanks for the input. Glen

Rob Lohman October 6th, 2003 06:36 AM

From your description the problem you are having is just too
high a contrast ratio. So the tip from Jeff does the trick indeed.
Although I haven't got any experience with this myself a silk
over the are you are shooting might help as well if you can set
that up.

Stephen Schleicher October 6th, 2003 10:56 AM

Diffusion
 
Rob beat me too it. I was going to suggest a large silk over the area. Westscotts Scrim Jim is pretty large and if you can suspend or mount the frame over the river (especially the area you are shooting) it might do the trick.


All times are GMT -6. The time now is 03:05 AM.

DV Info Net -- Real Names, Real People, Real Info!
1998-2024 The Digital Video Information Network