In article , C.H.Ling <chling@xxxxxxxxxxxxxx> wrote
>
>Below 1/60s reflect from film, above 1/60s reflect from shutter curtain.
>
Its not quite as binary as that CH. At 1/60s around half the exposure
is metered from the shutter curtain and half from the film.
Consider what happens as the shutter opens - the meter starts
integrating reflected light as the first blind traverses across the
film. At first all of the light is reflected from the blind, half way
open it is reflected from the blind and the film, and finally when fully
open all the metered light is reflected off the film. A short time
after the blind is fully open, enough light will have been metered to
trigger the trailing blind release - ending the exposure to each part of
the film as it traverses the focal plane.
At 1/125s around 75 0s metered from the blind and 25 0.000000rom the film.
At 1/30s around 250s metered from the blind and 75 0.000000rom the film.
The actual ratios are a bit different, because the blind travels across
the focal plane in less than 1/60s, but you should be able to see the
principle - the transition from metering on the film to metering on the
blind is gradual, not as sudden as you seem to indicate.
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's pissed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)
< 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 >
|