I previously asked a generic question regarding the means of
calculating
proper flash exposures. The responses I got were quite helpful
(thanks John
Doris, William).
But, now I'm having a problem because my flash unit's
(Vivitar 283)
exposure calculation chart doesn't list the film speed I need to
shoot at. It
only goes up to ISO 400.
Here is precisely what I'm attempting to do - - - I'm trying
to do a
full roll of triple exposures. The actual film speed is ISO
200. For all 3
exposures to be equally emphasized the normal calculation would
be
[3(exposures) x 200(actual ISO)] = 600. However, I wish to
emphasize the last
(3rd) exposure. Thus, I've already shot the first 2 exposures at
ISO 640 -
this was done with existing light, so no flash problems.
However, as I wish
to set the 3rd exposure at ISO 500, I'm unable to determine the
proper F-
stop/distance-to-subject for the aformentioned reason. Any
suggestions on how
to derive the proper settings?
Ted.
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|