In article <31620436.667B@oes.orst.edu>, brownt@oes.orst.edu says...

>I have a Nikon FA and a Sunpak 433D flash. I am new to TTL flash having
>"graduated" from the Nikkormat camera era with manual flash. As I
>understand TTL, the camera will sense the amount of light hitting the
>film plane and adjust the exposure accordingly. I was shooting some
>Fujichrome 400 film recently and when the flash was aimed directly at
>the subject, the TTL system worked fine. All pictures were properly
>exposed. When using bounce flash, however, all prints were at least >one or two stops underexposed. here is the question:
>Does TTL only work with flash directly on the subject?

No - I suspect there was just not enough flash power for the aperture
and distance used (bounce, even off a white ceiling at normal height,
takes many times more flash power than direct flash). The TTL meter
has no way of "knowing" where the light source is coming from.

>Perhaps I had my automatic settings on the camera wrong. I can't
>remember if I had the camera in full program mode or aperature or
>shutter priority.

Or Manual - it doesn't matter.

>Any suggestions would be helpful. I would like to use bounce flash >more often, but only if I can get proper exposure.

You may need a bigger flash, if you cannot use wider apertures
and/or faster film.
Hope This Helps