Alan Browne wrote:
David Farber wrote:
I was wondering about how fill flash affects the existing light. Of
course it will take the shadows and lighten them up a bit, but what
about the parts of the picture that are correctly exposed by the
existing light? I mean the light emanating from the flash (attached
to the hot shoe) does not just go to the shadows. Wouldn't the areas
not in shadow then be overexposed by a half stop? My fill flash
photographs (from print film) have been coming out nicely but this
conundrum has me scratching my head. On second thought, should I be
using some ratio method to compensate for the existing light
exposure or is that not how it's done? I'm using a Minolta Maxxum 7
with a 3600HS flash unit.

For the sake of fill flash, don't worry about it. Yes, they are
additive.

The Maxxum 7 has TTL-OTF metering for the flash. That is to say,
light coming off of the subject bounces off of the film into some
sensors at the bottom of the mirror box. When the flash return is
adequate the flash is stopped.

Assuming you are shooting in A-mode or P mode, the camera will
determine the shutter speed (and the aperture for P mode too) based
on the available light and the fact that the flash is on.

If the subject is that famous neutral grey of 12%, then simply set the
flash compensation wheel to -1, -1.5, -2 depending on how much fill
you need. For a lighter subject offset that setting to the positive;
darker offset further negative. (This applies for both the flash and
the available light compensations).

When you depress the shutter, the camera will set the shutter speed
(assuming A-mode) for the ambient light. Since you set a compensation
for the flash (above) that will quench the flash when that level of
flash return is received. For the balance of the exposure period, it
will be ambient based on the shutter speed. (Same for P-mode, but the
aperture is also chosen; opposite for Speed (and mind sync and other
limitations).

See the manual as well (I have a Maxxum 9 and Maxxum 7D; not the 7).
They explain this in some detail.

Hi Alan,

I've discovered that when you're in "A" mode (and I can only speak for what
the Maxxum 7 does), the selected exposure seems to ignore the ambient light.
For example, in a scene where f./8 @ 1/30th of a second would be the proper
exposure, the camera will recognize that the flash is enabled and then might
choose an exposure of f/8 @ 1/125 of a second. This pretty much decides for
you that the flash is going to be the main light instead of the fill light.
That is why I like to meter the scene in "M" manual mode so I'll know the
exposure will be correct with the given ambient light.

Thanks for your reply.
--
David Farber
L.A., CA