Shawn Wright wrote:
><On 20 Jul 98 at 6:30, VELUWEH@xxxxxxxxxx wrote:
>> Shawn Wright wrote:
>>
>> >I'd have to say that Hans view
>> >doesn't *sound* correct either, according to my understanding of the
>> >F280. If the 3-Ti could turn off the flash in FP mode, as it does in
>> TTL
>> >mode at 1/60 or less, this would result in part of the frame receiving
>> >*no* flash exposure if the shutter is above 1/60 (why else would one
>> >use FP mode). It's my understanding that the whole point of FP is that
>> >the flash consists of many short bursts such that they appear as a
>> >continuous light source to the film, even at 1/2000 sec. Cutting off
>> >the flash (as TTL does) would reduce the FP mode to TTL-equivalent, and
>> >its inherent limitation of approx 1/60 max shutter speed.
>> >That said, I suppose this must mean that the 4-Ti /F-280 must calculate
>> >the required FP flash intensity/shutter speed prior to exposure, since
>> >varying *either* of these values during exposure would also result in
>> >uneven exposure across the film plane. (again assuming shutter speed
>> >above 1/60) Which explains why the 4Ti *cannot* vary the shutter speed
>> >during exposure.
>>
>> The camera *can* control the Super FP flash duration. The duration,
>> which seems to be related to the flash burst frequency, can vary when
>> controled from an OM-4Ti or OM-3Ti between 1/25 and 1/50 of a second;
>> when controled by an OM-707 it can be between 1/30 and 1/70 (this is
>> related to the faster shutter of the OM-707). So "cutting off" the FP
>> flash wouldn't have the unwanted effect that part of the film doesn't
>> get any flash, but changing the frequency (flash burst) would result in
>> uneven exposure. After re-reading the FP-FAQ at
>>
>But at these speeds, it is simply quenching the flash as it does with any T
>series flash, so FP mode isn't an advantage (it just wastes batteries...).
It is not clear what "these speeds" Shawn is referring to, but IMO the most
important thing about the Super FP mode on
the F280 is synchnizing at high shutter speeds. It is daylight fill that this
Super FP flash on the F280 is designed
for. Since I have both the OM-4T and the F280, I am in the process of testing
my own method of using the F280. I have
already tried a few shots in the manual mode on the OM-4T by setting the
shutter speed so as to expose for the very
bright area of the frame which has a foreground in the shadow. The Oly
brochures for the OM-3Ti and the OM-4Ti in
Japanese have several illustrations of how the Super FP mode would be useful.
Most of these are very bright backlit
situations. Only one involves the shutter speed of 1/60 sec which shows the
motion of one hand on a guitar with Super
FP flashes. It gives a photo of the same setup showing the frozen motion of the
hand with normal flash.
The most dramatic example is one of a man who throws a crescent wrench up in
the air. With normal flash, his hand is
blurred but no wrench in visible in the picture. With normal flash in order to
get synchnization in daylight, you need
to stop down. This picture has a lot of background clearly. On the other
hand, with super FP flash, you open up the
aperture to get high shutter speeds. With the super FP mode and auto mode on
the 4T at 1/2000 sec, you can see clearly
the wrench in the air. The hand motion and the wrench are frozen. The
background is blurred because the aperture is
wide open.
This seems to be also a good illustration of how high shutter speeds are needed.
Tomoko Yamamoto
Photographer, Composer, Soprano
mailto:tomokoy@xxxxxxxxx
Home Page: http://www.charm.net/~tomokoy/
Olympus Classifieds: http://ep.com/ep/csp.html?csp=1130
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