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[OM] Why Minolta FP flash is so much stronger than OM

Subject: [OM] Why Minolta FP flash is so much stronger than OM
From: "Paul D. Farrar" <farrar@xxxxxxxxxxxx>
Date: Fri, 17 Dec 1999 18:25:35 -0600
The reason Minolta's FP flashes are so much more powerful (even usable) is
the camera's high X-sync speed. Even though the FP works above the X speed,
the faster shutter alows more efficient use of the energy storage capacity.
The reason is that the FP flash must be on for all times any part of the
shutter is open. This time is at least X+S, where X is the travel time (and
X-sync speed) and S is the shutter speed. Since any part of the film will
only see FP flash for S, the maximum possible efficiency of an FP flash is
E=S/(X+S). For S=X, E=1/2;
for S=X/2, E=1/3; etc. At 1/500s, on OM (X-sync=1/60s) can have a maximum
efficiency of 1/9, but a Minolta(X-sync=1/250s) can have 1/3. So at that
speed, Minolta can have triple the flash from the same storage capacity.

Another way of looking at it is that the Minolta exposure takes less time,
so the FP flash can be more intense.

Paul Farrar


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