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Old August 6th 04, 07:12 PM
Al Denelsbeck
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"Justin F. Knotzke" wrote in
:

quote who= Alan Browne /:
Justin F. Knotzke wrote:

for the background, close the aperture by 1-2 stops and increase
flash by 1.5 stops. I'll probably darken out some buildings and
backgrounds but my subjects should come out better and not look like
Casper's cousins.


If you increase the flash you will whiten them out and kill any
color they are wearing... esp. on slide film.


But wouldn't the descreased exposure compensate for that?



Depends on how exactly you're determining exposure.

If you're metering from ambient conditions with the intent of
dragging the shutter for those nice blurs, and the flash is TTL, then no
flash compensation should be needed. You still have to be careful and meter
the sky, to make sure it isn't overexposing at your camera settings, which
will blow out the film, and the flash will only pile on top of this.

If you're determining flash exposure by hand, remember that exposure
is cumulative. In other words, the flash by itself might be fine, and the
long exposure by itself might be fine, but the two together may equal
blowouts. So anything light colored that gets exposed by the flash, in an
area of the film already exposed by the sky, will go absolutely nuclear.

Once you pass the limits of the film, nothing you can do will bring
it back. You can't increase the flash to make the overexposure "even"
across the board - the film is already saturated. All you'll do is saturate
those areas that hadn't been. You have to drop overall exposure down to the
film limits, and this means decreasing both ambient exposure and flash.

It's much the same as a double-exposure. In order not to overexpose
the film, you decrease each exposure by a stop or so, because they'll pile
on top of one another. You're doing the same thing here - consider the
ambient blur exposure, and the flash going off, two separate exposures.
It's up to you to judge the conditions to know how they'll combine -
obviously the sky is a problem. So is anything white against white in the
two (good luck judging where the white helmet of a cyclist is gonna fall as
they race past you! ;-)). Very tricky, and I agree with the others that a
dark background is going to be your best bet.

Good luck with it! Get it right and the pics should be excellent!


- Al.

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