> Am I correct in saying Spot Fill Flash isn't
> possible?
The camera can't _automatically_ balance ambient light
and flash when using the spot meter, because the meter
only sees the main subject. Setting the correct exposure
for the background becomes your responsibility.
> Besides, what -is- spot fill flash -- I would
> have thought it let me expose a spot area using
> fill flash with the rest of the scene exposed
> by ambient light.
You could just meter the background manually, put the spot
on the main subject, and shoot. The camera will adjust flash
output to give correct exposure to whatever is under the
spot, but if the background is close enough to receive
illumination from the flash you'll have to compensate for
that yourself to prevent overexposure.
Spot flash is useful when you can't (or don't want to) balance
the background with the flash. It causes the camera to ignore
the background altogether. If you want balanced flash, switch
to matrix metering and let the camera see the background.
-Don
