ray_moth@xxxxxxxxx writes:
<< colour film may not support the reciprocity rule: 1 step increase in
f-stop = 1 step decrease in exposure time, and vice versa. >>
Ray,
I have just started using Delta100 and Delta400 B&W films (partly after
some discussion with Russ Gorman another list member) and while perusing the
Ilford literature I checked the reciprocity correction graphs for the films.
(http://www.ilford.com/html/us_english/bw.html) The interesting part is just
how soon you need to start correcting for reciprocity even with the higher
speed B&W films. The Delta400 for example needs to be corrected starting at
exposures of 1/2sec. At 30seconds the corrected value is 155 seconds! Even
with Delta3200 being faster, you might imagine it would be better but it has
the exact same correction factor. The OM would have to have its correction
dial set to a bit more than 2 stops. No wonder the OM's excell for low light
since at least they can time out to those long exposures if a correction is
dialed in.
Regards,
>>Tim Hughes<<
>>HI100@xxxxxxx<<
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