I'm planning to shoot hummers later this month.
One of the ways to stop wing motion is to use very bright fast flash. I'm NOT
going to use TTL (cost and nonpredictability). I have four optically slaved
Vivitar 283's with VP1's. Each 283 is powerful flash (GN 120 feet), but the
trick is to use all of them in manual mode at a fraction of its power (1/8th or
1/16th), because that yields a very short flash (on the order of 1/8000th
second or faster). Overall brightness is achieved by using multiple flash units
(and the more the merrier) very close to the subject (2 feet).
The camera lens will be stopped down to about f/32 (for depth of field) using
ISO 100 film, and I'll try to shade the subject from direct sunlight, in order
to reduce ghosting. I'm shooting with an OM-4 synced at 1/60s.
My question is whether I can supplement the 283's with slaved T20's or T32's.
The problem is that if any of the flashes have a longer duration, the edges of
the wings will be blurred. On the T32 in particular, there is a manual setting
that uses 1/4 power. The question is: how long is that flash duration? I've
looked in manuals, Olympus source books and the web but cannot find any such
info. The nominal flash duration of the T32 is states as "1/50.000~1/1000 sec",
but that says nothing about how to predict/control the duration.
I know I can get an even shorter flash duration out of the T32 or T20 by using
it in auto mode. By varying the distance of the flash to the subject, I can
control how much light any single isolated unit would put out. But when there
are multiple flashes being used, I'm less sure of how predictably the auto
works. Ideally I'd like to see a graph for the T32 with millisecs on the
horizontal axis, and power on the vertical axis. Any way to get that info?
BTW I do have a basic flash meter.
Any advice here?
BTW here is some excellent background info on shooting hummers:
http://www.rpphoto.com/howto/hummer/humguide1.htm
--
Matt BenDaniel
matt@xxxxxxxxxxxx
http://starmatt.com
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