Barry,
The F280 can work at 1/250 because the flash duration is long enough
(actually multiple flashes) to be useful.
The Kalimar flash is like any other standard flash. When you reduce power
to 1/16 (or 1/4, or 1/2, or 1/8 or anything less than full power) what is
happening is that the flash duration is shortened. (See Michael O'Carrigan's
post on the Vivitar 3500).
Let's say your flash puts out full power and the flash duration is 1/1000
sec. When the flash is set to 1/16 the flash duration may be 1/15000 sec.
That's how the flash has variable output, by changing flash duration. Same
thing would happen in auto mode, whether TTL or using the sensor on the
flash. Look at your specs on the Kalimar (or T32, or F280, or any flash
that has published specs and has auto capabilities). Flash duration will be
listed as 1/1000, or something similar, to a range of 1/40,000 or similar.
By reducing flash duration is how auto flashes have variable output. Full
is the max range, real short is close up or light subject.
Before thyristors came into use with older flashes, the output was still
variable, but wasted. Recycle time was a constant 3-15 seconds. With
thyristors, unused output can saved and used for next flash with much faster
recycle time. Again, see 3500 post.
Hope this helps.
Brian P. Huber
bphuber@xxxxxxxxxx
Troy, OH
-----Original Message-----
From: owner-olympus@xxxxxxxxxxxxxxx [mailto:owner-olympus@xxxxxxxxxxxxxxx]
On Behalf Of Barry B. Bean
Sent: Monday, June 14, 1999 9:31 AM
To: Zuiko-holics Anonymous
Subject: [OM] F280 vs 3rd party Fill Flash
I'm waiting on my F280 manual to arrive from Olympus, but in the
meantime, maybe someone can tell me the difference between a synced
F280 flash at, say, 1/250 and my 3rd party (Kalimar) 1/16 fill flash
at the same speed? Presumably, since there's enough light for the
camera to be shooting at 1/250, both flashes are fulfilling the same
function, right? And either way, my Om-4T will be using its OTF
metering and close the shutter when enough light has registered,
right?
On another note, I've gotten so comfortable with my tilting flash
head that the F280's fixed angle head is a decided handicap. I wish
Olympus had designed their flash with a tilt head.
BBB
-
B.B. Bean - Have horn, will travel
bbbean@xxxxxxxxxxxxxx
Peach Orchard, MO
http://www.beancotton.com/bbbean.shtml
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