The best description that i have found for Super FP flash is in Olympus
Vision Age issue # 6, which goes into more detail than the flash manual.
There, the flash duration is described both as 1/25 sec. and 40 milliseconds.
( A 'regular' flash unit gives a flash of 1 millisecond ) Also, I have a
Modern Photography article from Oct 1986 that introduces the OM-77AF camera,
and in that article it references Modern's August 1986 issue (pg. 82) for a
full discussion of the F280 flash; in case anyone has access to that issue.
Vision Age also mentions that the OM-4Ti's OTF metering system detemines the
actual exposure, and so, the camera is reading the subject brightness. This
reflected brightness is both the natural light, and the FP flash, so the
camera just meters the reflected light and selects the proper shutter speed,
and in this case, the natural and flash light are taken together, and so, are
balanced. The real value of a daylight Super FP flash used as a fill flash,
is, of course, you can select an aperture of say, 2.8 and a shutter speed of
1/100 or even 1/2000 and throw the background completely out of focus, and
hence, your subject will appear to 'pop' out of the background. With a nornal
flash sync speed of 1/60 sec, a daylight fill shot would force you to use an
F16 or F22 aperture on a sunny day.
George S.
frieder.faig@xxxxxxxxxxxxxxxxxxxxxxxxx writes:
The FP flash needs to fire contnious from the start of the first curtain to
the arrivial
of the second cutain: -> "fire time" = curtain time + exposure time.
For 1/2000 sec: minimum fire time = 13.5ms + 0.5ms = 14 ms (~ 1/70sec)
For 1/500 sec: minimum fire time = 13.5ms + 2ms = 15.5 ms (~ 1/65 sec)
For 1/60 sec: minimum fire time = 13.5ms + 16.7ms = 30.2 ms (~ 1/33
sec)
For 1/30 sec: minimum fire time = 13.5ms + 33.3ms = 46.5 ms (~ 1/22
sec)
I ignore the need for some security ms to compensate for timing overlaps to
assure
the whole image is covered with the flash. So a flash duration of 1/25 is
necessay to
cover safely 1/60sec exposure time, and almost 1/30sec of exposure time.
Another interesting calculation:
46.5 ms /14 ms = 3.32
80 flashes * 3.32 = 265 flashes
So I guess it is only the flash duration, which saves the energy of the
capacitor,
and that 1/50-1/25 sec is only a rough approximation. ... well I´m only
guessing!
Frieder Faig
P.S: Still having a F280 for red eye control but no 4T/Ti.
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