Greetings Mike
> This subject has probably been thrashed at this point, but I'm
> still confused. If the purpose of 3DMBFF is to balance flash
> light with ambient light, then what's the point in using it?
The point of using the flash during daylight conditions
("synchro-sunlight") is to reduce the range of brightness levels in
the scene to fit into the capabilities of the film.
3D MSBFF is designed to give (what the designers believe to be) just
the amount of flash required for the subject relative to the other
brightness levels in the scene, so that the camera "balances"
the ambient light in the background with the flash illuminated
foreground. The flash is not exactly the same level as the ambient
light as this would look very unnatural.
"Fill flash"( as in centre-weighted or spot) is not balanced because
the fill compensation level is only relative to the brightness level
that you specifically meter.
For example with a backlit portrait you have 2 options:
i) With balanced fill flash, you meter for the bright background
(using matrix metering) and the flash illuminates the foreground for
a "natural" effect, so the entire scene is recorded faithfully.
ii) With fill flash (say spot) you can meter only the foreground
subject and the flash output will be relative to the ambient light
level on the foreground subject only. The background will be grossly
overexposed!
Generally you want between 1(ratio = 1:2) and 2 (1:4) stops less
flash light than ambient light for a "natural" effect. Any less flash
and the flash is hardly having any effect at all. Any more and the
flash becomes overpowering and the whole scene looks very unnatural.
Hope this answers your question.
Regards
Anthony
[EMAIL PROTECTED]
