Enrique asked:
>>>>>- - I always have thought that the main fill-in flash use was to
provide some light for a subject against a very bright background. If
you do that in Auto, the averaged meter reading may not ask for
flash... Should I assume TTL is of no use there? (subject will come
out dark, background bright)>>>>>
First of all, I'm not an expert on this. I have NOT shot transparencies
using TTL to acquire first hand experience. That said, he goes, based on
the T32 manual and the book I mentioned 2 days ago.
No, the book does NOT mention using TTL to fill faces in daylight. In fact
my OM-2 isn't smart enough to recognize a back lit face from a front lit
one.
What the book does recommend is using MANUAL flash pops to do fill flash for
faces. Naturally, since we're talking about manual flash, we're talking
about a *single* shooting distance to match the background exposure. And we
need a big whollop of flash exposure from a T32. Here are my notes for full
sun, from a table in the book. The Guide Numbers quote values at ASA (EI)
100.
== FULL SUN ==
Shadows are Distinct
--
Kodacolor 100, with correct exposure in full sunlight, the manual exposure
of 1/60th @ f 22, (for the background). [Remember, the sunny 16 rule
suggests 1/125 at f/16. An electronic flash on a TTL equipt OM-2 or OM-PC
will not "sync" at that speed. It will only expose one half of the frame by
flash at 1/125. So you have to use the sync speed of 1/60th and stop down
to f/22, possibly using the 50mm f/3.5 macro for example, stopped all of the
way down, which incidently is not the sharpest aperture. Anyway....]
============== 1:1 ratio ================
Without the zoom adapter, using a T-32 at full, manual power, the
calculation is:
104 = GN in feet
so 104/22 = 4.7 feet
Lenses: 28 and up
(The book points out that we "think" of this as a 1:1 ratio but the ratio is
calculated based on the indoor flash values which assume reflective white
walls and an 8 foot reflective ceiling, typical in America for example. In
reality, we're talking about using the flash as *fill*, outdoors, so our
calculated "correct" flash exposure is slightly on the underexposure side.
That is, since we don't get the flash bouncing off those reflective room
boundaries, we don't really get as much light as the scales tell us. That's
why the 1:1 ratio, normally undesired because the flash is too bright, is
about right, according to the author. Anyway....)
============== 2:1 ratio ================
Without the zoom adapter, using a T-32 at full, manual power,
6.5 feet (but the flash is underexposed 1 full stop)
Lenses: 28 and up
So, there it is. Using a manual flash firing, there is exactly one shooting
distance in full sunlight. Notice that in full sun, we are shooting a
subject from 4.7 feet away with the full power of a T-32. This is not gonna
make you a popular guy. Also note that a smaller flash, like the popular
T-20 doesn't have a chance!
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