At 10:51 3/25/02, you wrote:
Actually, at a shutter speed of 1/250, wouldn't each point on the
film be exposed for precisely 1/250 of a second? Otherwise, the
effective shutter speed would be something else, in this example,
1/1000.
Walt Wayman
Clarification: "1/4th of that" refers to 1/4th of a 1/60th shutter curtain
travel time which works out to 1/250th. For an exposure of 1/250th with
focal plane shutter curtains that require 1/60th second to traverse the
entire film gate, the slit will be about 1/4th the width of the film gate.
Mea Culpa for imprecision/ambiguity in how I phrased it.
In reality, the OM shutter curtains must be a bit faster than that . . .
likely about 1/80th or 1/90th second . . . so X-sync at 1/60th shutter
speed will work properly with at least a little bit of time with the film
gate entirely open. In the OM's, the slit width at 1/250th would have to
be closer to 1/3rd the width of the film gate. Someone such as John H. or
Clint would likely know exactly how fast the curtains are supposed to be
and the exact slit width for a shutter speed can be worked out from there.
-- John
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|