--- Bob Turner <[EMAIL PROTECTED]> wrote:
> Hi Folks,
>
> A request for some advice :
>
> We will be having our annual stock check over the
> next few days and I have
> been asked to record some of the functions within
> the factory.
>
> I'll be using the 550EX flash under indoor sodium
> lighting, is there
> anything I should be cautious of, or any particular
> filters I need to use
> on my lens?
>
> My preferable lens will be the 28-135 IS mounted on
> a 50e.
If you really want to try to balance flash and ambient
in this situation, the only way to do it is with
complementary filters. i.e, an orange filter on the
flash to make it's light match the sodium, and a blue
filter on the lens to compensate. But I'm afraid I
have no idea how much filtration would be necessary.
Sodium vapor lights put out virtually light in the
blue spectrum at all, so I think you'd need huge
amounts of filtration to shoot on daylight film.
Tungsten film would be better, but would still require
some filtration, I think. In the end, the level of
light reaching the film would be very low, which
causes it's own problems.
My approach would probably be to minimize the
contribution of ambient light, so the exposure is
primarily made by the flash. I'd go for the highest
shutter speed you can manage to reduce ambient light
exposure. The 28-135 isn't very fast, though, so that
might limit you a bit. Stay as close to your subjects
as possible.
The backgrounds will probably still be very orange,
but I don't think there's much you can do about that.
At least it won't look as bad as the green backgrounds
you get with mercury vapor lights.
HTH.
=====
Bob Meyer
Life is uncertain. Eat dessert first.
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