On Fri, 26 Dec 2003 03:23:03 GMT, "Marvin Hlavac" wrote:

because the areas that look white are supposed to be beautifully light green
fresh color of X-mas moss. I tried to play with WhiteBalance setting on the
camera but I obviously don't know what I'm doing :-(

That's not a white-balance problem. It is simply a case of the
highlights being "blown out". In other words, the camera metered
the light at a darker spot in the tank, and so the brighter areas
ended up being too bright. A lot of times I find that in aquarium
shots, the range of dark shadows and extremely bright highlights is
more than the camera can handle. It's usually better to end up with a
darker shot, to avoid blowing out the highlights. The shadows end up
being too dark, but that can often be corrected afterwards in your
image editing software. Blown out highlights can't be fixed, since
there is nothing but white pixels saved by the camera. With the dark
shadows, there is often enough detail to fix it.

Many digital cameras have several metering modes. Usually they have a
"spot" metering, where the metering is done from the very center of
the shot. In that mode, I will usually put the center spot on an area
that is the brightest, hold the shutter button part-way down, which
locks the focus and exposure on most cameras, then re-frame the
picture as desired, and push the button the rest of the way to take
the shot.

Another common mode is a "center weighted" where the camera takes the
exposure reading from a wider area around the center point. This mode
is more likely to pick a setting that will avoid some of the blown out
highlights.

And finally, most cameras have an "exposure compensation" setting.
All this does is to tell the camera (take your exposure reading, and
make it x.xx darker or x.xx brighter. If I see that the highlights
were blown out on a shot, I'd retake the shot with a -1 exposure
compensation.




Chuck Gadd
http://www.csd.net/~cgadd/aqua