The F-280's advantage is that it can sync at all shutter speeds with the
OM-4T(i), OM-3T(i), and OM-77(Plastic). This makes it the absolute best for fill
flash in bright sunlight. Compared to the T-32 GN of 32M (104 ft.) the F-280's
GN of 28M (91 ft.) in normal TTL mode is only slightly less, however some
believe the flash anaemic. The bottom line: If you own a T-32 you should only
consider the F-280 if daylight fill flash is important to you. Since the F-280
only works (in all modes) with a small number of Oly's and has received a
reputation as underpowered, you can get near mint used examples for relatively
little gelt (I picked one up for $105).
The Shipman book has this to say:
Olympus developed a novel electronic flash, the F280, which is the electronic
equivalent of an FP flashbulb. The F280 has two modes. It can fire in a single
short-duration burst, the same as conventional electronic flash. This mode is
used with X-sync shutter speed or slower.
Or, the F280 can "spread out" the light to occupy a longer time, such as 1/40
second -- which is called Super FP mode. In this mode, the flash tube does not
emit light continuously. It is pulsed on and off, 20,000 per second. To the
film, it appears to be continuous light.
The total amount of light produced in the two modes is about the same. As an
analogy, the single-burst mode can be thought of as a dollar bill while the
Super FP mode is like 100 pennies. (I agree here with Shipman that the total
amount of light produced is about the same, but the effective amount of exposure
in FP mode is highly dependant on the shutter speed in use. The long duration
ensures that during the shutter's entire travel, the same amount of light is
seen, but the portion of the 1/40 second flash that reaches the film at 1/2000
is much less than at 1/25. Therefore, the fill flash effectiveness and working
range varies greatly throughout the shutter speed range. With the very short
flash durations of conventional flash, the entire energy output always occurs
within the longer duration of the fully-open FP shutter. Here syncing refers to
the firing of the flash during the time when the entire film frame is exposed.
Syncing in Super FP really emulates the old flash photo technique of holding
open the shutter and then firing of a bulb or flash powder. The upshot of all
this is that you must be aware that you get less fill flash at higher shutter
speeds and you should have a thought process like-- I want more effective fill
flash therefore I need a slower shutter speed, and therefore I need a smaller
aperture. So remember, F280 fill flash, while superior, is not 100% automatic
and does not take the photographer's input out of the exposure decision! Another
way to think of it is, the meter will properly expose the scene, but the ratio
of ambient to fill flash will differ based on shutter speed, e.g. slower speed=
more fill)
With the F280 in Super FP mode, there is no upper limit to the shutter speed
except what is available on the camera. You can use 1/2000 second, for example.
At shutter speeds of X-sync or slower, the super FP mode has no advantage over
conventional single-burst mode. Either may be used...(actually, it DOES have the
DISADVANTAGE of not stopping motion)
With ordinary flash, if the ambient light is bright there may be two images of a
moving subject. One is sharp image produced by the short duration flash. The
other, a ghost image may be blurred. Using a faster shutter speed with the Super
FP flash will prevent the ghost image (BUT THE FLASH WILL NOT FREEZE MOTION! In
fact, you can use the F280 to properly fill flash outdoors while panning a
moving object and you'll retain the backgroung motion blur WHEN SHOOTING AT SLOW
SHUTTER SPEEDS.) There is only a single exposure made by the ambient light
augmented by the long-duration light from the flash. By choosing shutter speed,
you can control image blur of the moving object.
Another advantage is automatic flash fill in daylight. In TTL automatic mode,
the sensor in the camera body measures both light from the flash and ambient
light. It ends the exposure when sufficient light has been measured. At
distances normally used for people pictures, the F280 does not overwhelm the
daylight exposure. The result is that the F280 fills the shadows automatically,
without any figuring or calculations. It will also improve exposure of a subject
against a bright background.
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