On Thursday, May 02, 2002 at 12:22, Thomas Bryhn
<olympus@xxxxxxxxxxxxxxx>
wrote re "Re: [OM] Bryhn Chart method of F280" saying:
> At 20:30 01.05.02, Tom Trottier wrote:
>
> >I disagree. I suggest the ratio is always set by the flash-subject
> >distance, since the flash amount is constant.
>
> We don't disagree, but you simply state the obvious. The question is how do
> you decide the required fill-in-ratio without careful metering first, and
> how do you know what *exposure* the camera will choose (even though this
> will not affect the ratio)?
What's "required" can be predetermined, e.g., always 1:2 or 1:4. Or,
as you seem to suggest, you can meter similar surfaces in the
shadows and in the highlights and decide how much extra exposure the
shadows deserve.
I just predetermine.
> The camera will meter like an OM-2, except that you'll have an
> additional lightsource that can't be seen in the viewfinder. If
> you're able to judge and control this within 1/3 stop even when
> the background and subject have different brightness, then I'm
> very impressed. But as always, just continue to do whatever works
> for *you*.
If the background and subject have identical lighting, than the F280
will not only fill in the shadows, but brighten the subject vs the
background. (This also depends on how close the background is to the
flash compared to the subject to flash distance.)
With some tests, you can judge what fill ratio will have what effect,
and therefore choose your distance according to the effect you want.
Using the 3T or 4T's auto exposure in this situation will average
between the subject and background, but the center weighting will
usually pull it towards the subject exposure.
With manual metering, you need to do the calcs in your head,
underexposing a little to compensate for the extra light.
The easy way is to use auto exposure for many subjects, but for
caucasian faces, you may just want to use the indicated manual
exposure since you want the face to be brighter than an 18 0rey
card.
Great chart, Tom
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